10+ days of crisis at the Fukushima Daiichi nuclear power plant – 22 March 2010

Update: Detailed graphical status report on each reactor unit is available. Here is the picture for Unit 2 — click on the figure to access the PDF for all units.

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Yes, it really has been that long. So what happened during those 10+ days? For a long answer, look back over the daily posts on this blog, which also has plenty of links to more off-site information. For the short-hand version, I offer you this excellent graphic produced by the Wall Street Journal:

Credit: Wall Street Journal: http://goo.gl/E9YuA

Things continue to develop slowly, but I think now towards an inevitable conclusion — barring any sudden turn of events, a cold shutdown (reactor temperature below 100C) should be achieved in units 1 to 3 within the next week (or two?). The other priority is to get the spent fuel storage sufficiently covered with water to make them approachable (and ideally to get AC power systems restored to these ponds, as has been the case already for units 5 and 6). The clean up, diagnostics, and ultimate decommissioning of Fukushima Daiichi, of course, will take months and years to complete.

What is the latest news?

First, there is a new estimate of the tsunami damage. According to the NEI:

TEPCO believes the tsunami that inundated the Fukushima Daiichi site was 14 meters high, the network said. The design basis tsunami for the site was 5.7 meters, and the reactors and backup power sources were located 10 to 13 meters above sea level. The company reported that the maximum earthquake for which the Fukushima Daiichi plants were designed was magnitude 8. The quake that struck March 11 was magnitude 9.

Second, the IAEA reports elevated levels of radioactivity in the sea water off the coast of these reactors. That is hardly surprising, given that contaminated cooling water would gradually drain off the site — and remember, it is very easy with modern instruments to detect radioactivity in even trace amounts. These reported amounts (see table) are clearly significantly elevated around the plant — but the ocean is rather large, and so the principle of disperse and dilute also applies.

I’m reminded of a quote from James Lovelock in “The Vanishing Face of Gaia” (2008):

In July 2007 an earthquake in Japan shook a nuclear power station enough to cause an automatic shutdown ; the quake was of sufficient severity-over six on the Richter scale-to cause significant structural damage in an average town. The only “nuclear” consequence was the fall of a barrell from a stack of low-level waste that allowed the leak of about 90,000 becquerels of radioactivity. This made front page news in Australia, where it was said that the leak posed a radiation threat to the Sea of Japan.The truth is that about 90,000 becquerels is just twice the amount of natural radioactivity, mostly in the form of potassium, which you and I carry in our bodies. In other words, if we accept this hysterical conclusion, two swimmers in the Sea of Japan would make a radiation threat.

For further details on radiation trends in Japan, read this from WNN. In short, levels are hovering at or just above background levels in most surrounding prefectures, but are elevated in some parts of Fukushima. However, the World Health Organisation:

… backed the Japanese authorities, saying “These recommendations are in line with those based on accepted public health expertise.”

Below is a detailed situation summary of the Fukushima Daiichi site, passed to me by a colleague:

(1) Radioactivity was detected in the sea close to Fukushima-Daiichi. On March 21, TEPCO detected radioactivity in the nearby sea at Fukushima-Daiichi nuclear power station (NPS). TEPCO notified this measurement result to NISA and Fukushima prefecture. TEPCO continues sampling survey at Fukushima-Daiichi NPS, and also at Fukushima-Daini NPS in order to evaluate diffusion from the Fukushima-Daiichi. Though people do not drink seawater directly, TEPCO thinks it important to see how far these radioactivity spread in the sea to assess impact to human body.


Normal values of radioactivity are mostly below detection level, except for tritium. (detection level of Co-60 is 0.02Bq/ml) Also, samples of soil in the station have been sent to JAEA (Japan Atomic Energy Agency).

(2) Seawater injection to the spent fuel pool at Fukushima-Daiichi unit 2. This continues, with seawater injected through Fuel Pool Cooling and Cleanup System (FPC) piping. A temporary tank filled with seawater was connected to FPC, and a pump truck send seawater to the tank, then fire engine pump was used to inject seawater to the pool. Although the water level in the pool is not confirmed, judging from the total amount of injected seawater, 40 tons, it is assumed that the level increased about 30 cm after this operation.

(3) Brown smoke was observed from unit 3 reactor building. At around 3:55 pm on March 21, a TEPCO employee confirmed light gray smoke arising from the southeast side of the rooftop of the Unit 3 building. Workers were told to evacuate. It is observed the smoke has decreased and died out at 6:02pm. TEPCO continues to monitor the site’s immediate surroundings. There was no work and no explosive sound at the time of discovery.

(4) Smoke from unit 2 reactor building (as of 9:00pm, March 21). TEPCO’s unit operator found new smoke spewing from mountain side of unit 2 reactor building around 6:20 pm, which was different smoke from blow-out panel on the sea side. There was no explosive sound heard at the time. At 7:10 pm, TEPCO instructed workers at unit 1 – 4 to evacuate into the building. Evacuation was confirmed at 8:30 pm.

(Note: Since there was another smoke found from unit 3 at 1:55pm and evacuation was completed at that time, no workers were remained at the units when smoke found at unit 2.)

TEPCO assumes the smoke is something like vapor, but are still investigating the cause of this smoke with monitoring plant parameters.

Radiation level near the Gate of Fukushima-Daiichi NPS increased at the time of smoke, then decreased to prior level.

5:40 pm 494 μSv/hr

6:10 pm 1,256 μSv/hr

6:20 pm 1,428 μSv/hr

6:30 pm 1,932 μSv/hr

8:00 pm 493.5 μSv/hr

As a result of smoke from unit 2 and 3, scheduled water cannon spraying operations for March 21 were postponed.

(5) Power supply restoration at unit 2 (as of 5:00 pm, March 21). Power cables have been connected to the main power center (existing plant equipment) and confirmed as properly functioning. Presently, soundness tests of the equipment are underway. A pump motor, which is used to inject water to spent fuel pool, has been identified as needing to be replaced.

Similar power connections have been made to reactors 5 and 6 and a diesel generator is providing power to a cooling pump for the used fuel pools. Power cable is being laid to reactor 4, and power is expected to be restored to reactors 3 and 4 by Tuesday.

Kyodo News now reports that all 6 units are connected to external power, and control room power and lighting is about to be restored.

The water-spraying mission for the No. 4 reactor, meanwhile, was joined by trucks with a concrete squeeze pump and a 50-meter arm confirmed to be capable of pouring water from a higher point after trial runs.

With the new pump trucks arriving, the pumping rates for water spraying has increased to 160 tonnes per hour through a 58 metre flexible boom via remote control.

Here is the latest FEPC status report:

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  • Radiation Levels
    • At 04:30PM (JST) on March 21, radiation level outside main office building (approximately 1,640 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 2,015 micro Sv/hour.
    • At 06:30PM on March 21, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 1,932 micro Sv/hour.
    • Measurement results of ambient dose rate around Fukushima Nuclear Power Station announced at 1:00PM and 4:00PM on March 21 are shown in the attached two PDF files respectively.
    • For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
  • Fukushima Daiichi Unit 1 reactor
    • At 2:25PM on March 21, pressure inside the reactor core: 0.198MPa.
    • At 2:25PM on March 21, water level inside the reactor core: 1.75 meters below the top of the fuel rods.
    • At 2:25PM on March 21, pressure inside the primary containment vessel: 0.16MPaabs.
    • As of 4:00PM on March 21, the injection of seawater into the reactor core continues.
    • As of 7:00PM on March 21, external power generation is connected and the functionality of the electric devices is being checked.
  • Fukushima Daiichi Unit 2 reactor
    • At 2:25PM on March 21, pressure inside the reactor core: -0.023MPa.
    • At 2:25PM on March 21, water level inside the reactor core: 1.35 meters below the top of the fuel rods.
    • At 2:25PM on March 21, pressure inside the primary containment vessel: 0.12MPaabs.
    • At 2:25PM on March 21, the temperature of the spent fuel pool: 122.0 degrees Fahrenheit.
    • At 6:22PM on March 21, steam was emitted from the secondary containment building. (Under investigation)
    • As of 4:00PM on March 21, the injection of seawater into the reactor core continues.
    • As of 7:00PM on March 21, external power generation is connected and the functionality of the electric devices is being checked.
  • Fukushima Daiichi Unit 3 reactor
    • At 9:30PM on March 20, the Tokyo Fire Department began to shoot water aimed at the spent fuel pool, continuously until 3:58AM on March 21 (roughly 1,137 tons in total).
    • At 12:25PM on March 21, pressure inside the reactor core: -0.083MPa.
    • At 12:25PM on March 21, water level inside the reactor core: 1.6 meters below the top of the fuel rods.
    • At 12:25PM on March 21, pressure inside the primary containment vessel: 0.120MPaabs.
    • At 3:55PM on March 21, gray smoke was emitted from the secondary containment building.
    • At 4:49PM on March 21, the gray smoke changed to white smoke, but the volume of the smoke was unchanged.
    • At 6:02PM on March 21, it was confirmed that the emission of smoke had ceased.
    • As of 4:00PM on March 21, the injection of seawater into the reactor core continues.
    • As of 7:00PM on March 20, about 3,742 tons of water in total has been shot to the spent fuel storage pool.
    • As of 7:00PM on March 21, activities for connecting an external power supply are underway.
  • Fukushima Daiichi Unit 4 reactor
    • At 6:22PM on March 20, 10 Self Defense Force vehicles began to shoot water aimed at the spent fuel pool, until 7:43PM (roughly 81 tons in total).
    • At 6:37AM on March 21, 12 Self Defense Force vehicles and TEPCO began to shoot water aimed at the spent fuel pool, until 8:41AM (in total about 91 tons). TEPCO used one high pressure water cannon supplied by the US Army.
    • As of 7:00PM on March 21, roughly 83 tons of water in total has been shot to the spent fuel storage pool.
    • As of 7:00PM on March 21, activities for connecting an external power supply are underway.
  • Fukushima Daiichi Unit 5 reactor
    • At 4:00PM on March 21, the temperature of the spent fuel pool: 108.1 degrees Fahrenheit.
    • As of 7:00PM on March 21, external power generation is connected and the functionality of the electric devices is being checked.
  • Fukushima Daiichi Unit 6 reactor
    • At 7:27PM on March 20: cold shutdown
    • At 4:00PM on March 21, the temperature of the spent fuel pool: 96.8 degrees Fahrenheit.
    • As of 7:00PM on March 21, external power generation is connected and the functionality of the electric devices is being checked.
  • Fukushima Daiichi Common Spent Fuel Pool
    • From 10:37AM to 3:30PM on March 21, roughly 130 tons of water in total has been injected into the spent fuel storage pool.

Our official sources are:

  • Office of The Prime Minister of Japan
  • Nuclear and Industrial Safety Agency (NISA)
  • Tokyo Electric Power Company (TEPCO) Press Releases
  • Ministry of Education, Culture, Sports, Science and Technology (MEXT)

And, to wrap up this report, the the Japan Atomic Industrial Forum has provided their 19th reactor-by-reactor status update (19:00 March 22):

I’ll probably only do a detailed report once every few days now, as things are no longer changing quickly, and we have other issues to start exploring. There’s another reason too — I’m exhausted!

 

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391 Comments

  1. “Tokyo (CNN) — Reactors 1 and 2 at Japan’s earthquake-stricken Fukushima Daiichi nuclear power plant suffered more damage from seawater than originally believed and will take more time to repair, the plant’s owner said Tuesday.”

    [link deleted -did not support above statement. Please re-submit with the correct link]
    What is the current best-case definition of “repair”?

    –bks

  2. TEPCO believes the tsunami that inundated the Fukushima Daiichi site was 14 meters high, the network said. The design basis tsunami for the site was 5.7 meters, and the reactors and backup power sources were located 10 to 13 meters above sea level. The company reported that the maximum earthquake for which the Fukushima Daiichi plants were designed was magnitude 8. The quake that struck March 11 was magnitude 9.

    This leaves a rather different impression regarding the design. Early reports seemed to imply that the emergency generators had been foolishly built without protection from a tsunami. This update suggests that they were clearly positioned with a tsunami in mind. Just not one this big.

  3. Reports that during the periods of grey smoke yesterday/today, site radiation levels spiked to nearly 2000milliSV and personnel were of course withdrawn. When the smoke went away, levels dropped somewhat.

    The BBC reported Tepco as speculating the smoke might be from “oil” left by damaged equipment and that the very high rad levels are from a wind change.

    I think the only real explanation is that the fuel is moving/settling as the structures are collapsing/warping.

    IIRC, the World Trade Centre Towers were discovered to have an expansion rate problem in the steel re-enforcement of the concrete.

  4. The seawater reference has made me do a fun calculation.

    Chernobyl released an estimated 14 EBq of radioactivity.

    The worlds oceans contain a lot of uranium and potassium-40 and other isotopes which are radioactive.

    The worlds oceans contain about 15000 EBq of radioactivity.

    The world’s oceans contain a THOUSAND Chernobyls worth of radiation.

    Think about that next time you go to the beach!

  5. I suspect in the coming weeks as the facts, and not the hype, becomes known a lot people will be increasingly coming to the realization that this event speaks in favor of nuclear power, not against.

    More than a few people have changed their stance from against or neutral to *pro* nuclear due to Fukushima:

    “Why Fukushima made me stop worrying and love nuclear power”
    George Monbiot, # guardian.co.uk, Monday 21 March 2011 19.43 GMT

    Article excerpt:
    “A crappy old plant with inadequate safety features was hit by a monster earthquake and a vast tsunami. The electricity supply failed, knocking out the cooling system. The reactors began to explode and melt down. The disaster exposed a familiar legacy of poor design and corner-cutting. Yet, as far as we know, no one has yet received a lethal dose of radiation.

    Some greens have wildly exaggerated the dangers of radioactive pollution. For a clearer view, look at the graphic published by xkcd.com. It shows that the average total dose from the Three Mile Island disaster for someone living within 10 miles of the plant was one 625th of the maximum yearly amount permitted for US radiation workers. This, in turn, is half of the lowest one-year dose clearly linked to an increased cancer risk, which, in its turn, is one 80th of an invariably fatal exposure. I’m not proposing complacency here. I am proposing perspective.”

    ParetoJ

  6. I tried to post this in a previous thread but I guess the discussion has now moved here

    This follows a prior discussion regarding these thermal images

    https://lh3.googleusercontent.com/-7nl69Z9ja64/TYeY3KBTWyI/AAAAAAAAA8c/jd7CCYy8bW4/s1600/heatAll.jpg
    https://lh3.googleusercontent.com/-igGlJ5nIl3A/TYeaSWrOc9I/AAAAAAAAA8k/cMF1N9ReFuw/s1600/Fukushima_hoch_DW__1340857z.jpg

    red_blue:
    “Image of reactor 1 is somewhat disconcerting, because the peak heat areas appear to be above the reactor pressure vessel proper and not the SFP. This could indicate leaks around the top shields or their circumferencial support plugs, but is inconclusive”

    @red_ blue

    regarding n.1, I have also read that
    ” TEPCO executive vice president, Sakae Muto, said the core of reactor No.1 was now a worry with its temperature at 380-390 Celsius (715-735 Fahrenheit).
    “We need to strive to bring that down a bit,” Muto told a news conference, adding that the reactor was built to run at a temperature of 302 C (575 F).
    http://ca.reuters.com/article/topNews/idCATRE72A0SS20110322?pageNumber=1&virtualBrandChannel=0

  7. Reports that during the periods of grey smoke yesterday/today, site radiation levels spiked to nearly 2000milliSV and personnel were of course withdrawn. When the smoke went away, levels dropped somewhat.

    It would be interesting to note where this claimed 2,000 mSv/h was measured and who is the source. All correct site measurements have been done in uSv/h and there was no such spike today or yesterday in TEPCO’s own measurements. The latest data they have posted is 2300 JST (so 1.5 hours old) from the main gate, which is 235.9 uSv/h. The highest spike today was 472.7 uSv/h at 1930 JST.

    Last time the mobile unit measure radiation at the high dose rate area (closest temporary monitoring station to the reactors, 500 m distance) north of the office building was yesterday at 1630 JST at which time it was 2015.0 uSv/h.

    I think what could be going on is that media monitoring these readings doesn’t understand that the highest measurements from the plant area come from this car that drives between several stations (during the last days only between the main gate and north of the office building) and the difference between the 500 m and 1,000 m measuring stations is one order of magnitude (250 -> 2,500 uSv/h). There is no concern when the car moves from the gate to the north of the office building, you would expect the measurement to increase by x 10 each time the car moves.

  8. All correct site measurements have been done in uSv/h…

    Referring to the standard monitoring system including the car, measurements done by patrols engaged in spray operations or other work have been in the mSv/h range (such as readings taken less than 50 m from the reactor buildings on the west reactor service road).

    …you would expect the measurement to increase by x 10 each time the car moves.

    Of course, when the car moves back to the main gate from the north of the office building, the dose rate it measures drops to 1/10, but that’s never “newsworthy”.

  9. I would like to comment on the table Barry has provided above on the radioisotopes in the seawater around the crippled reactors. The one isotope that raises questions is I-132. The half-life of this isotope is only 2.3 hrs. There could not have been any of this left in the fuel. I was initially worried this could indicate fission still occuring in the reactors, but I-132 is being produced by the parent isotope Te-132 which has a half-life of 76.9 hrs, so just over 3 half-lives. I-132 should be approaching equilibrium with Te-132, which means the activity of both are roughly equal, i.e. as much I-132 is being produced from Te-132 as is decaying away. If the Te-132 activity was also measured it would allay any concerns fission is still occuring in the reactors, but the decay chain mechanism is the most likely.

    http://www.wolframalpha.com/entities/isotopes/iodine_132/pt/h5/gx/

  10. nmsalgueiro writes, referring to our host,

    Your cover of this whole affair has been incredible

    I agree — except for a stylistic nitpick. What Barry has been has been credible. That is why more than half the site’s hits have come in the last ten days.

    And come to think of it — who was so desperate to deny me my victory in the million-hit-prediction pool that they triggered that earthquake?

  11. regarding n.1, I have also read that
    ” TEPCO executive vice president, Sakae Muto, said the core of reactor No.1 was now a worry with its temperature at 380-390 Celsius (715-735 Fahrenheit).
    “We need to strive to bring that down a bit,” Muto told a news conference, adding that the reactor was built to run at a temperature of 302 C (575 F).

    That temperature alone should not be a big problem as long as the pressure stays within limits (it’s currently about 1/20 of operating pressure). Also, you would not expect amounts detectable by IR imaging of that temperature to radiate from the thick concrete upper shield (or actually several layers of shield slabs), not even if the reactor was operating.

    I think the most reasonable explanation for that temperature reading at that exact spot is that some equipment (most likely parts of the crane) have fallen there and then the roof remains have fallen on top of it, creating kind of a “tent structure”, where the collapsed roof remains are highest at that spot (which is also shifted a little to the west from the center of the reactor pressure vessel top). Any heat buildup under the collapsed roof would concentrate on the highest spots of the collapsed structure geometry. Alternatively, temperature differences can come from variations of thickness of remaining roof material.

    Remember that at reactor building 1, the roof top collapsed as a whole on top of the refueling floor, while in buildings 3 and 4 the roof panels were blown completely off and the steel grid structure remained somewhat erect (building 4 almost completely erect and building 3 partially collapsed, but not down to the refueling floor level).

  12. If there’s a thousand times more radioactivity in the oceans than Chernobyl released, how does that sound like Chernobyl released a lot of radiation if you are not an unreasonable person?

    What is the total amount of radioactivity in Bq that was released by Fukushima?

  13. David Martin, on 23 March 2011 at 3:08 AM said:

    CNN are reporting at 16:30 GMT that damage to reactors 1 & 2 from seawater corrosion is much more extensive than they had thought.

    I raised this concern here when I first learned they were injecting seawater into the core. Hot salt water is very corrosive. The heat exchangers and pumps were designed for using de-ionized water. There are going to be many leaks as they circulate this salt water through the system to restore normal cooling. The pumps are likely to seize up. Replacing the pumps and/or heat exchangers will be problematic as they will have radioactive material deposited on them.

    Do you have a link for this report?

  14. ‘Earlier Tuesday, Tokyo Electric Vice President Sakae Muto said the No. 1 and No. 2 reactors at the plant suffered more damage from seawater than originally believed and will take more time to repair.

    The tsunami that followed the 9.0-magnitude earthquake March 11 damaged electrical components and coolant pumps in units No. 1 and 2. Those are two of the three units now believed to have suffered damage to their reactor cores, Muto said.

    Reactor No. 2 suffered more damage than No. 1, and the earliest those parts can be replaced is Wednesday, Muto said. The cause of the damage was unclear, but seawater was pumped in previously to cool the reactors as an emergency measure after the earthquake.’

    http://edition.cnn.com/2011/WORLD/asiapcf/03/22/japan.nuclear.reactors/index.html?hpt=T2

  15. The oceans are huge. One thousand is not that many. Fukushima is nowhere near the league of Chernobyl.

    David Martin, I would say that damage to the equipment, like pumps and other machines, may be more extensive than they thought. The reactors themselves are intact, inside their containment and pressure vessels. So to me this means we have to be patient while they replace damaged ancillary equipment.

  16. TEPCO said emergency generators were located 10 to 13 meters above sea level. They also said that damage due to sea water is more extensive than originally estimated.

    Even if the generators were not flooded there was still a problem with sea water wetting any electrical equipment in lower locations. Unlike fresh pure water, the sea water is far more conductive to electricity, hence any electrical equipment wetted with sea water is prone to short circuit and failure, therefore, the electric back up system would most likely fail anyway. Electrical control wiring and electric control equipment is especially sensitive to moisture. Minor failure in electric control system can disable power circuits. The problems in control wiring are very difficult and time consuming to find. No doubt there are serious problems with electric system because it took 8 days to bring in power, they say from 1.5 km away, and restore equipment to working condition and it is not all done yet. Once more, there is evidence that electric back up system is not reliable source of power for emergency reactor cooling.
    This did not have to happen if steam driven turbo pumps were used for emergency cooling, utilizing steam from reactor itself. As it stands, the anti nuclear crowd will point out the lack of cooling incident is Fukushima for a long time to come

  17. seamus, on 23 March 2011 at 3:43 AM said:

    The reactors themselves are intact, inside their containment and pressure vessels.

    I would say that is incorrect. There is damage. The extent and how much radioactivity may be leaking out is not known. The main source of radioactivity has been from pressure release from the primary containment. This has decreased and hasn’t been done recently, but there are other sources of radioactive release. The SFPs being a primary suspect. See the latest JAIF reactor report.

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300796691P.pdf

  18. Another report of interest is JAIF earthquake report No. 23. Tokyo Fire Department has sprayed 3 times the pool capacity of unit 3 SFP. The water is leaking out and going somewhere, probably the ocean. Unless their aim is very bad and they don’t correct it. That they haven’t had to spray as much at unit 4 SFP also indicates they have a serious leak in the pool of unit 3.

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300796691P.pdf

  19. The water is leaking out and going somewhere, probably the ocean. Unless their aim is very bad and they don’t correct it.

    At least the videos of the first spraying operations with the ARFF vehicles showed that clearly a large portion of the water was falling outside of the entire reactor building. Even assuming they had improved this (by higher pump power and/or clearing rubble to position the vehicles closer), it would be reasonable to assume that 1/3 of the water getting to the pool is probably the upper limit of their effectiveness.

    The concrete pouring vehicle is an entirely different animal, with which almost 100% accuracy to a target the size of the pool even from the level of the damaged roof should be expected.

    The ARFF vehicles are designed to fight fires resulting from aircraft accidents and typically spray at distances of less than 10 m against a target that is at the same level (not 30 m higher) with clear line of sight and good illumination even during night and heavy fog/rain etc. Some of them carry airframe penetration nozzles, which are only usable when the vehicle is within about 3 meters from a crashed aircraft.

    The remotely operated concrete pour vehicle is designed and operated at these heights and higher, with accuracies of less than meter for where the pour must land.

    It’s important to keep in mind the limitations of equipment not designed for this kind of work and personnel who have no experience or training for anything like this. Aiming even the standard ARFF spray accurately from inside the vehicle against a target at the same level and of the shape and size they are trained with, is quite difficult due to the showers created.

    They often have to operate them in bursts. First spray some and then look where it lands, correct, spray again, etc. until continuous spray can be maintained. In this case they had very little in terms of gauging effectiveness or in aiming so that most of the flow would land on the pool.

  20. There has likely been some damage to the exposed fuel rods in the cores (probably the main source of radionuclides), but as far as we know, the reactor vessels are intact, and the torus on #2 has been damaged.

    The reason they didn’t spray water on #4 was because there was still some water in the pool (despite irresponsible speculation otherwise), and the SFP at #3 was more urgent. And just because they sprayed more water than capacity on #3 doesn’t necessarily mean there’s a leak. Quite possibly a lot of it didn’t get in the pool, there’s a lot of debris up there. There’s no clear indication of leaks in any of the SFPs. There’s been speculation, but no solid evidence. Without circulation, it seems that evaporation alone is enough to reduce the water level significantly over days. Now that the situation at #3 has improved, they are indeed turning their attention to the SFP at #4.

  21. One reason I suspect a leak in SFP 3 is that the heat of the fuel in SFP 4 is higher, so evaporation should have been higher in 4, but they concentrated on 3. Maybe there was more sloshing in unit 3 that decreased the level, so there are other mechanisms.

  22. Mattias Svensson says,

    Where can I find a heat chart? What I mean is when you shut down a reactor how much heat is left after lets say a week

    There’s one in Luke Weston’s recent guest posting here.

    Fission fragments produce little heat per decay, i.e., the sum of such a decay’s beta-ray and gamma-ray energies is small, compared to the energy of the alpha-decay of a fuel nucleus that captures a neutron but does not fission. The fastest-decaying of these that I know of is curium-242, half-life a little over 160 days if I recall, and so for the first few weeks it is reasonably accurate to include only beta-decay energy in the residual power calculation.

    This being so, you can use the Untermeyer and Weill rule for that. It says the post-fission-shutdown power ‘t’ seconds after fission stops, as a fraction of average fission power during a run time of ‘T_0′ seconds, is


    0.1*
    (
    (t+10)^(-0.2) - (t+10+T_0)^(-0.2)
    - 0.87*
    (
    (t+20000000)^(-0.2) - (t+20000000+T_0)^(-0.2)

    )
    )

    At 10.5 days, I get this working out as 0.0029. At 12 hours after the earthquake, which I seem to recall is about when the batteries ran out, it was 0.0083.

    That is why improvised emergency cooling measures are working better now.

    (Anyone going to the Darlington public hearings? Would you like me to go?)

  23. The above information shows both reator 2 and 3 having neagative core pressures and both have a portion of their fuel rods uncovered. Reactor 2 core has negative 0.023 MPa (negative 3.34 psi) and reator 3 core has negative 0.083 MPa (negative 12.0 psi). With a negative 12 psi the water would be boiling around 140 degrees F and to get such a low pressure it seems to me there would need to be significant cooling/condensation in the process. Even when the power generation system is working normally is it possible to have -12 psi at the condensor end of the turbine, much less in the reator core? Would someone explain? Thanks.

  24. @cyril “Chernobyl released 14 EBq of radioactivity” is a misleading statement. The satement is basically saying that at the moment of release, there were 14 x 10^18 radioactive decays per second. But most of those decays are from Xenon, Krypton, and Iodine with half lives of hours to weeks. Within a few hours, the decay rate might be down to half that rate. Since the actual process of release was sustained for many hours, what does this even mean? Are two significant digits (14) even warranted? Comparing that radiation level to that in the oceans is meaningless. By the time Chernobyl-sourced radiation made it into the ocean, its decay rate was probably down by at least 2 orders of magnitude. Today, the contribution to the world’s radioactivity of Chernobyl is probably nearer to a millionth of the radioactivity in the oceans than it is to a thousandth.

  25. Hi!

    A lot of not so smart people fled Tokyo immediately by plane. I read that an international flight from Tokyo to America will expose them to roughly 50-100 microsievert, making the radiation from the trip much higher than the radiation in Tokyo.

    I am now wondering how high the radiation is from x-ray and security checks at the airports? Could you help?

  26. G.R.L. Cowan, hydrogen energy fan until ~1996, on 23 March 2011 at 5:21 AM said:

    Fission fragments produce little heat per decay

    Technically you are talking about fission products. The fission fragments are what are produced at the moment of scission, even before the release of neutrons. These fragments have a kinetic energy of around 190 Mev. That is where most of the energy is released in the fission process. Alpha decay has an energy of around 5 Mev and the beta/gamma decay that happens later is in the 100s of kev range. But there are a lot of them for each fission as the products go down the decay chain to stable isotopes. Did my thesis on predicting fission fragment yield, so that is why I’m nitpicking. ;)

    http://www.nucleonica.net/forum/showthread.php?173-Fission-fragments-versus-fission-products-what-is-the-difference

    A proposal for using fission fragments directly.

    http://en.wikipedia.org/wiki/Fission-fragment_rocket

    There is also a reactor “design” with 90 % efficiency

    http://en.wikipedia.org/wiki/Fission_fragment_reactor

  27. What makes no sense to me is that the last temperature reported for pool #4 was 84 degrees C on the 14th, and there were various reports of it boiling, yet based on the infrared it’s claimed pool #4 was only 42 degrees C on the 20th. According to the IAEA and other sources, the decay heat in pool #4 is close to 2 MW, with 1331 assemblies versus a decay heat of 0.25MW and 514 assemblies in pool #3. Yet the infra red shows pool #3 at 62C, and that’s where the bulk of the spraying is going. How likely is it that the SFP would drop 40C spontaneously, especially when it’s the one with by far the most decay heat? If it’s dry, why isn’t it hotter on the infra red? If it’s wet, what’s keeping it cool?

  28. With all the news focused on the fear coming from low levels of radiation to the public here is one news paper article that uses actual data from Nuclear bomb survivors to show Radiation Doserates actually increasing their lifespan and health. http://www.nationalpost.com/todays-paper/Reactor+victims+will+benefit+studies+show/4480863/story.html

    Radiation Hormesis also demonstrated by the medical profession in Japan and supported by technical papers provides support for this from the medical cancer treatment side. this link covers the basics and gives reference to the studies supporting it.
    http://www.angelfire.com/mo/radioadaptive/inthorm.html

  29. Lessons learned from TMI and Chernobyl were actually enacted by the industry. This is the next level of enlightenment for public safety in my opinion.

    Some national nuclear safety agencies have already reacted even before IAEA guidance to make preliminary inquiries to their supervised nuclear energy companies about at least the following issues:
    – review of design environmental threats and protection measures
    – SBO scenarios and extended accident management (beyond DBA) guidance in place
    – backup electricity sources, offsite and onsite
    – backup coolant sources, offsite and onsite
    – interfacing with offsite rescue services, such as the general fire brigade, army and portable electricity generation

    Preliminary reports about these issues will probably be release much sooner than even a preliminary accident investigation report to the still ongoing situation in Fukushima.

  30. “The clean up, diagnostics, and ultimate decommissioning of Fukushima Daiichi, of course, will take months and years to complete”.

    Analysis of TMI bottom vessel steel took more than 10 years…

    I think generally there is under evaluation of the true impact of this issue.
    I. E. the explosion in building 3 was great, probably with damage of the pool with fuel…

    We have no data of Sv values on the vertical of buildings.

    You Barry are exhausted, I truly understand you. But the fuel is not exhausted, it will work each day, 24 hours per day, for many, many years.

    Ciao from Italy

  31. Barry/David evening,

    The issues seem to be alot less than early on in the event. They can logically deal with them as reported or occur now. Final details will take months to come out in factual reports. Facts as known currently, this situation seems to be stabilizing. But maybe that’s purely on my opinion.

    Factual impacts and challenges yet seen will be eventually disclosed, unless they involve security effects. Lessons learned will be enacted by the industry, that I am sure of.

    It’s actually good to see preliminary figures on beyond the concurrent design basis events that occurred published.

    I was somewhat aware of how far this pushed some of them. But without technical documentation to support, was not going to comment.

    I also know that doesn’t make people feel good, but it seems to appear the design margins to address the assumed values were conservative and prudent.

    Lessons learned from TMI and Chernobyl were actually enacted by the industry. This is the next level of enlightenment for public safety in my opinion.

  32. “For the short-hand version, I offer you this excellent graphic produced by the _Wall Street Journal_”

    Edward Tufte (author of _The Visual Display of Quantitative Information_ and many other incisive works on presentation graphics) would tear that to pieces for its sloppiness.

    For one thing, it glaringly and inaccurately depicts the hydrogen explosions as “burst” symbols with a radiation hazard icon inside of the burst.

    Thereby implying to the casual or scientifically illiterate reader that a nuclear explosion had occurred, instead of a chemical explosion.

    There are about a half dozen other obvious lapses of informationally precise presentation in just that one page. And I’m not even by any means a specialist in that discipline.

  33. G.R.L. Cowan, on 23 March 2011 at 2:28 AM said:[...]

    There was a lot of traffic at The Oil Drum during the DH debacle for the same reason. Everyone else was babbling about the oilcano.

  34. Just looked at Rod Adams “Atomin Insights” blog.
    Several days ago, he posted on this blog a topic called “Stop Worrying about Spent Fuel Ponds, Zirconium tubes do not burn”, which was cited by Barry Brooks.

    This topic and associated comments have been deleted from “Atomic Insights”. The only thing I can find is:

    http://theenergycollective.com/rodadams/53997/stop-worrying-about-spent-fuel-pool-fires-zirconium-tubes-do-not-burn

    There you find the following:

    Stop Worrying About ‘Spent’ Fuel Pool Fires. Zirconium Tubes Do Not Burn
    Tags: earthquakeEnergyjapannuclearNuclear Powerzirconium

    comments Posted March 20, 2011 by Rod Adams

    The contents of this post were incorrect. I acknowledge the error and apologize.

  35. Some further updates:

    (1) Atmospheric Radioactivity in Fukushima-Diichi site area TEPCO has reported NISA and Fukushima prefecture on detection of atmospheric radioactivity in Fukushima-Daiichi NPS. TEPCO sampled air on March 19, 20 and 21, then identified radioactivity exceeded the limit for radioactive workers (Japanese law stipulates limit of atmospheric radioactivity concentration for three months average not exceeding 50 mSv even if workers breath this air one year)
    Iodine-131 concentration was relatively high, 2.30 times of the limit for March 20 sample and 1.52 times for March 21.
    Normal radioactive plume discharge concentration is 5 x 10E -6 Bq/cm3 for Iodine-131. (this value is equivalent to 1mSv if breath the air one year.) We believe this level of radioactive concentration is not an immediate danger, but we will continue to monitor atmospheric radioactivity and workers have already equipped with charcoal mask.

    (2) Result of additional radioactive material survey in the seawater around Fukushima-Daiichi NPS On March 21st 2011, radioactive materials were detected from the seawater around the discharge canal (south) of Fukushima Daiichi Nuclear Power Station.
    TEPCO had conducted re-sampling survey in the wide range of area to examine the effect of radioactive materials in the seawater. Details are as follows;

    (3) Off-Site Power restoration status as of 11:00pm March 22nd

    The power restoration work was started around 8:00 am. All the cable installment tasks have been completed by the morning of March 22nd (between 8:00 am and 10:30 am). The soundness test is still under progress. It is difficult for us at this moment to clearly decide when the work will be completed.

    Current status:
    (Unit 1/2)
    Reestablishment of power cable to the existing receiving equipment in Unit 2 building has been completed. Soundness test of the equipment and facilities inside Unit 2 building is under progress. As such, the main control room and other equipment inside have not yet been energized.

    (Unit 3/4)
    “Connection” of power cable to the temporary receiving equipment on the site has been completed.
    At 10:35 am, tests to energize between the temporary receiving equipment and the existing receiving equipment in Unit 4 have been completed. Currently the test has been conducted for the equipment at load side.
    Unit 3 main control room recovered power for lighting at 10:43 pm on March 22. The power has not been supplied to equipment in the building.

    (Unit 5/6)
    Reestablishment of power to the existing receiving equipment in Unit 5 and 6 buildings has been completed. The central control center and Residual Heat Removal system which is necessary to cool the reactor are being energized.

    (4)Water spray to 1F-4 spent fuel pool using concrete pumping vehicle.
    A concrete pumping vehicle sprayed 150ton seawater to spent fuel pool at unit 4, from 5:17 pm to 8:30 pm on March 22. TEPCO has decided to use this concrete pump for spent fuel cooling on March 18, since then we trained workers for the operation as well as to bring the vehicle to the power station under the severe road conditions due to the quake.
    The radiation level around the site was 3.0 – 10.0 mSv/hr.
    Though we think the concrete pumping vehicle is very effective, we will continue to take all measures to conduct the restoration work with the cooperation of organizations involved.
    A camera was set at the end of the water spray arm. We will assess the status of the pool after the spray this time when we retrieve the camera.

    This vehicle is designed to inject concrete at high elevation.
    – Width of the vehicle: approximately 2.5m
    – Length of the vehicle: approximately 15m
    – Weight of the vehicle: approximately 55 tons
    – Length of the arm: approximately 58m
    – Discharge rate: approximately 0 to 160 tons per hour
    – Manufacturer: Putzmeister (Germany)

  36. “Second, the IAEA reports elevated levels of radioactivity in the sea water off the coast of these reactors. That is hardly surprising, given that contaminated cooling water would gradually drain off the site — and remember, it is very easy with modern instruments to detect radioactivity in even trace amounts. These reported amounts (see table) are clearly significantly elevated around the plant — but the ocean is rather large, and so the principle of disperse and dilute also applies.” Barry Brook.

    So “the principle of disperse and dilute also applies”. What kind of scientific proof are you showing to asseverate this fact? That radioactivity dilutes harmlessly in seawater. Because I haven’t seen a link in the text to prove this fact. You censored my previous post (not very polite, by the way) cause I didn’t put links to prove my opinion, so it’s fair you show me now yours.

    “At 2:30 p.m. Monday, TEPCO collected 500 milliliters of seawater at a point 100 meters south of the outlet, from which waste liquid is drained into the sea.
    A total of 5.066 becquerel of iodine-131 per milliliter was detected, a level 126.7 times more than the yearly limit a person can safely ingest as set by the Nuclear Reactor Regulation Law.
    If a person ingested two liters of water at this level of contamination over a three-day period, it would be equivalent to being exposed to an annual dose of radiation according to government-set safety standards, the Nuclear and Industrial Safety Agency said.”
    DAILY YOMIURI ONLINE
    http://www.yomiuri.co.jp/dy/national/T110322004914.htm

    126.7 times the yearly limit is way far of dilution of radioactivity, and add this to tainted vegetables, milk, tap water, dust and rain and I can assure you are going to receive a fair amount of radiation if you stay at Fukushima and surroundings.

    I’m going to trust every advocate of nuclear safety at Fukushima if he drinks two litres of that water and eats vegetables and food from there. And I want videotaped proof. :)

    As far as I know, not even a high rank government official has put a foot (not to say a Minister or the Prime Minister) on the zone, so I presume it must not be a safe place at all.

    Respect “the principle of disperse and dilute also applies”, here it goes a proof that it doesn’t:
    “”These aren’t levels of contamination that pose an immediate impact,” said Junko Matsubara, former professor at Yokohama City University. “Should the current level of concentration continue, however, consuming contaminated marine products could have an impact on the health.””
    DAILY YOMIURI ONLINE
    http://www.yomiuri.co.jp/dy/national/T110322004914.htm

    Also,
    “What general advice can be given to food consumers and producers in the event of a nuclear emergency?
    Many other short-, medium- and long-term actions need to be considered in areas confirmed to be seriously contaminated, such as: [...] avoid fishing.”
    WORLD HEALTH ORGANIZATION
    http://www.who.int/hac/crises/jpn/faqs/en/index7.html

    There is something funny about how the Japanese government try to downplay the risks of radioactivity:
    “Radioactive materials that exceeded regulation levels have been found in seawater around the endangered Fukushima nuclear plant, but government officials offered reassurances Tuesday they will not have an immediate effect on people’s health.”
    THE JAPAN TIMES ONLINE
    http://search.japantimes.co.jp/cgi-bin/nn20110323a2.html

    So, the regulation levels have been excedeed but there is not an inmediate effect on people’s health. Why the reason of putting a safety level in the first place if it doesn’t matter when it’s surpassed? Cancel the levels! You are safe even it’s surpassed by 127 times! The Japanese government keeps you saying that everything is ok in spite of radioactive food, radioactive tap water, radioactive seawater, radioactive dust, and radioactive rain/snow.

    It’s a pity people use common sense and don’t trust the government:
    – “Evacuees forced out of their homes by the March 11 earthquake and tsunami have begun a fresh exodus to escape the threat of radioactive fallout from the crippled Fukushima No. 1 nuclear power plant.
    At least 21,000 people had left evacuation centers for other prefectures as of Saturday, according to a count by The Asahi Shimbun. Most of the evacuees are from Fukushima Prefecture.”
    THE ASAHI SHIMBUN
    http://www.asahi.com/english/TKY201103210075.html
    – “The institute has been inundated with inquiries on radiation exposure.
    More than 1,000 people had called by Saturday, tying up all six telephone lines. Callers included people living in the Kanto region.”
    THE ASAHI SHIMBUN
    http://www.asahi.com/english/TKY201103210086.html

    Even the medical proffesion is running away:
    – “About one-third of the hospital’s 108 doctors and 730 nurses are absent. Many of them are believed to have left the city to avoid possible exposure to radiation.”
    THE ASAHI SHIMBUN
    http://www.asahi.com/english/TKY201103210084.html

    Finally, the geniuses at the government are doubting if put a ban on seafood at the zone.
    “”Given the current situation, I cannot rule out any possibility (including a ban on seafood), but it is not necessary at the moment,” Edano said. “But it is necessary to collect data from a wider range and firmly continue to have experts analyze them.””
    THE JAPAN TIMES ONLINE
    http://search.japantimes.co.jp/cgi-bin/nn20110323a2.html

  37. Pingback: Some reader comments, reverse chrono order, Part-1. | World's Only Rational Man

  38. William Fairholm, thanks for the link about possible sources of leaks from the SFPs. The March 19 post by Dave Lochbaum has some interesting information about how reactor to pool transfers work. He says “In addition, reports from Japan say that the spent fuel pool at reactor Unit 4 is leaking, which further increases the need for additional water.” But the only other reports of this that I can find are articles quoting Lochbaum. For example: “David Lochbaum… suspects water is leaking out of the No. 4 spent fuel pool through a seal that, because of the loss of power, is no longer water tight.” http://www.energycentral.com/generationstorage/nuclear/news/en/19271506/Expert-Browns-Ferry-vulnerable-to-leak-like-Japan-plant

    Maybe we’ll find out when the pools are topped off and it’s safer to get in there and see what’s going on.

  39. “NEWS ADVISORY: No. 2 reactor power repair work halted, 500 millisievert per hr radiation found” 11:13 23 March (JST)

    If confirmed, this measurement is the highest spot radiation field dose rate measurement to date for the entire crisis. On the other hand, encountering higher radiation fields inside the reactor and auxiliary buildings should be expected considering all that has happened there. Reactor 2 is also the one where containment damage (at least for the pressure suppression pool) is suspected with supporting evidence, since over a week ago.

  40. So, the regulation levels have been excedeed but there is not an inmediate effect on people’s health. Why the reason of putting a safety level in the first place if it doesn’t matter when it’s surpassed?

    Industrial work safety, food safety, chemical safety and other similar safety regulatory systems work on principles of reducing risks to as low levels as practicable and usually contain high safety margings. The idea is that if there is any exceedance of a norm, there will be sufficient time and other protective measures in place to correct the defiency, _before_ any health effects come observable.

    In the case of radiation and especially radionuclide contamination, these safety margings are much higher than in many other fields, for various reasons, such as:

    – The most likely effects of radiation is increase of cancer risk, which takes years to many decades to manifest itself and diagnostically is from very difficult to completely impossible to attribute to any given carcinogen at the time of diagnosis, which means, that when the effects are actually realized, it’s too late to do anything about it.

    – The risk estimates of extremely low doses (less than the variability of background/natural radiation, which in itself is over 100 times) are based on an untested and untestable theory, which is essentially the worst case estimate used instead of actual knowledge of harmfull effects.

    – Hysteria: Because below extremely huge and always fatal doses, it’s impossible to detect radiation by human senses, and consequently radiation as a health risk is a big uknown to the general population, creating much irrational fear of the uknown.

  41. @Red_Blue.
    I was reading your and Barrys comments on previous posts, something on your opnion changed since that?
    Is the situation under control? I don’t mean: Everything is okay, and this kind of stuff, but it can’t get worst than it was, right? Sorry about my poor grammar, my main language is japanese.

  42. Yohak, why the fuss?

    There is no need for your long-winded rant. Not only was it unwarranted [excessive language deleted] it also ignores basic truths.

    Firstly, to demand that a reference be provided to support the notion that 500ml of water, when mixed with the waters of an ocean, actually dilutes! I am shocked! Indeed, once the dilution factor achieves 128, then all reported isotope concentrations will be below the reporting limit, ie of no interest to the regulatory authorities. So what’s there to worry about?

    At that point, your own concerns will become baseless. As per the table at the head of this thread, three limits have been exceeded and publicly reported.

    With a half-life of 8 days, the offending isotope will naturally decay by a further factor of 128 in 7*8 = 56 days, after which time you can be doubly assured that no nasty exceedances remain. I have no doubt that assessment of the real world impacts will be reviewed and assessed and talked about for some time to come, but the fact remains, that once the waters have been diluted in the Pacific, there will be no cause for further alarm. There will be no ongoing public health threat and there will be no threat to the food chain.

    The only threats after dilution will be those which arise due to incomplete dilution, eg possible uptake in molluscs of certain species, or in aquatic vegetation, and even these will dissipate rapidly with time. I am sure that there are many suitably qualified people who will be involved in ensuring that hypothetical secondary effects are assessed and monitored and that, where doubt exists, actions such as bans on fishing are put in place.

    You have added precisely nought to the process of rational assessment, review and response which will ensure that the community’s health will not be damaged through these releases.

    Finally, where are your manners? Barry brought these figures to your notice. He explained why he was confident that they would not be of lasting concern. Without Barry’s open and frank attitude, you would not even know that the isotopes had been released. [excessive language deleted]

  43. To the Moderator:

    My contribution, above, includes some content which breaches the rules of fair play on this site.
    Sorry for that… delete as appropriate.

    I tend to get stroppy when confronted by [excessive language deleted] outbursts. Perhaps I am human. For this, I apologise.
    MODERATOR
    Just a little trimming needed. :)

  44. @Red_Blue.
    I was reading your and Barrys comments on previous posts, something on your opnion changed since that?

    I’m not sure which comments you are referring to. I’ve been cautiously optimistic for almost a week now due to the last major releases of activity on March 16th (with the explosion in unit 4). I think the most likely juncture in this accident development was with those hydrogen explosions obliterating the last barrier (secondary containment) between the cores/spent fuel pools and the environment.

    Most SBO, cooling failure, containment failure scenarios end with the hydrogen burn in the secondary containment and the core release fraction (outside of the reactor building) not going up after that. These scenarios assume almost total core melt and reactor pressure vessel failure and do not account for controlled pressure release to prevent PRV or containment vessel failure. Also, these scenarios have a timeframe of about battery life + 7 hours (or in our case 15 hours since SBO), so they are not applicable to the timeframes we have seen in Fukushima.

    We don’t yet know enough about the status of the cores to preclude the situation worsening, but it seems now much less likely than a few days after the quake.

    Is the situation under control?

    In my opinion it’s not yet completely under control, because the cooling of the cores and SFPs is still being maintained by ad hoc extended accident management efforts with completely uknown and unmodelled long term effectiveness.

    I think one key problem is the usage of salt water in the PRV. I have seen saturation calculations (which are based on the boil off rates with the assumed decay heat values) that after about 1.5-2 weeks of pumping in seawater, natrium cloride (sea salt) concentrations will reach solidification fractions and further pumping will be impossible until temperatures and pressures will reach PRV failure levels.

    As don’t know yet how much outflow there has been or what the condition of the cores are, assessing the salt water concentration risk is very difficult.

    Other possible problems are associated with reactor equipment damaged by the initial quake and tsunami as well as the hydrogen explosions, venting of very high pressure steam to the reactor building (possible damage to the air conditioning system ducts, if they have not been reinforced like in the US plants), leakage of seawater from the SFP and reactor cooling operations, etc.

    So in summary, it could get quite a bit worse than today with all radiation measurements trending down (no further major releases for several days), but the probability is decreasing with every day there is active and well coordinated work onsite to bring things under control.

    We might be able to make better risk evaluations when the control rooms of reactors 1&2 and 3&4 are fully functional with (undamaged) all of the standard and backup instrumentation available.

    My understanding is that the remote consoles used for the last week lacked displays for much of the critical data, for reasons unknown. TEPCO has recently reported recovery of PRV temperature readings for example, which is good news for properly adjusting their seawater injection flows (which they have already done also).

  45. An fascinating quote: ” You can’t reason someone out of a position they didn’t reason themselves into.”

    The fascinating thing is it seems to apply to many sides of this discussion.

  46. Quotes from the latest update from JAIF, discussing some of the issues I just mentioned:

    􀁺 TEPCO will conduct test operation for pumps, which are to inject water into the reactor at unit-3. External AC power to the main control room of Unit-3 became available at 13:43 of March 22. (10:55, March 23)
    􀁺 Nuclear and Industrial Safety Agency announced in its news briefing held around 10:00 AM on March 23 that the core temperature exceed design value of 302℃ and reached almost 400℃ at Unit-1. Core cooling function was enhanced through increasing number of injection lines, given this situation. (10:55, March 23)
    􀁺 The work to recover external AC power for units-1, 2, 3 and 4 of Fukushima Daiichi nuclear power station is in progress. External AC power to the main control room of unit-3 became available at 13:43 of March 22. Now the lights are working in the room and working condition has been improved. Unit-3 is the first unit that external AC power became available among four units which are in severe condition. TEPCO will provide eternal AC power to systems for cooling the reactor and the suppression pool after checking availability of these systems at unit-3. Also the work to connect AC power line to distribution panels for Unit-1, 2 and 4 was accomplished. However, pumps of Unit-1 and 2 for cooling were covered by seawater and maintenance work is necessary for these pumps. (04:15, March 23)
    􀁺 The Ministry of Education, Culture, Sports, Science and Technology will expand the area for monitoring radioactive nuclides in seawater to 30km, offshore, given the situation that seawater sample collected surrounding area contains radioactive nuclides in excess of the legal standards. (04:15, March 23)
    􀁺 Most meters and gages have been unavailable in the power station since station blackout occurred after the earthquake. Meanwhile, temperature instrument to measure surface of the reactor of unit-1, 2, and 3 was restored and becomes available. (04:15, March 23)

  47. @Red_Blue
    Thanks a lot, seriously, I was really worried about the situation, half of my family still 40km from Daichii Plant.
    NHK reports are driving people (without base knowledge about the problem) crazy, and they sound like TEPCO isn’t capable to hold on the situation.
    Again, thank you for clarifying all those situation!

  48. At UTC-5 away from the scene, I’ve been pulling for the engineers and technicians at Fukushima Daiichi.

    One concern voiced here by several has been that the use of seawater for reactor or SFP cooling is undesirable due to precipitation, corrosion and damage to components. If this is a significant danger to the overall effort, can someone please explain why fresh water supplies are not being used? Are the volumes required too large to truck in? Is well water unavailable or also a bad choice?

  49. DrD, on 23 March 2011 at 3:40 PM — I certainly don’t know by this time. At the beginning seawater was probably all that was available. Seawater obviously remains convenient. I’m sure the nuclear operators are aware of the salt buildup problem and switch to fresh water before that adds to the difficulties.

  50. Thanks a lot, seriously, I was really worried about the situation, half of my family still 40km from Daichii Plant.

    Just to make it clear, if my family was there, I would make what ever arrangements were necessary in advance to get them out even if there were no nuclear plant issues, because of the overall situation.

    The actual decission to leave on the other hand should be based on credible information and evaluation of the risks and costs of self evacuation compared to the risks of staying. The risk of leaving could be serious due to road conditions and aftershocks (like last night) alone.

    It’s interesting to note that there is a small region nort west of the plant about 30-40 km away, where the dose rate has been above levels for sheltering in place (staying inside), but apparently the government has not decided to extend the sheltering area towards this direction on the account of most people self evacuating this low population rural area.

    Your family members should have a reasonable amount of time available to leave, if they are 40 km away from the plant and with some means of transport (to a local evacuation center at least) available, because it will take several hours of any possible fallout to reach them, should a major new release of radionuclides take place at the plant.

  51. @Red-Blue 2:55 PM ” I think one key problem is the usage of salt water in the PRV.”

    I agree that this may be a potential key problem. It depends on the details of how sea water injection into the reactors has been managed, and details of the reactor pressure vessel which I don’t have.

    I think that sea water is injected into the RPV for cooling core decay heat by generating steam. The steam is vented. Sea water contains about 3.5 wt% salts, mainly NaCl, but many others too. Over time, the sea salts can be concentrated in the sea water that remains in the PRV. At some point, the salt concentration gets so high that salts precipitate as solids possibly plugging PRV internals and fuel assemblies . My back of envelope estimate is 35-50% salt would be the saturated solution at high temperatures.
    If the managed sea water injection into the PRV by both venting steam and also pressuring out some concentrated sea water, it would be possible to keep salt concentrations below saturation. This would involve the release of some radioactive water.
    Does anybody know how they are managing sea water injection into the PRV’s?

  52. MODERATOR
    I have been away for several hours and standards are already slipping. Now I am back!
    Several comments have been deleted because they were unsupported hearsay designed to alarm people.
    BNC is a science blog – please support your comments with references/links.
    Incivility/rudeness/ad homs have also started to creep back – they will not be tolerated on BNC.

  53. Pingback: alQpr » Blog Archive » Don’t Stop Darlington

  54. Does anybody know how they are managing sea water injection into the PRV’s?

    I haven’t read any word about any pumps or other methods of removing liquid water from the reactors being used.

    The quickest access that comes to mind for draining some of the RPV inventory is through the reactor water cleanup system, but I have no idea how hard tapping that line for a new connection and a pump would be in the accident conditions. Probably not very easy. Incidentally, this system could be also used to remove trace amounts of sodium cloride and other salts and impurities from the water, if it had power and was otherwise in working condition.

    They probably have spent the manpower and other resources elsewhere. The seawater cooling was most certainly intended as a stopgap until normal cooling systems can be brought back online.

    It seems there is still have huge demand/supply disparity of clean or even fresh (low salt) water if they have really injected seawater to cool the external spent fuel storage pond, since decontaminating that will be costly and some damage to fuel rods and equipment might be expected.

    Since the water treatment facilities are not designed to work with seawater, any large quantity/reservoir of plant process water tainted with seawater added, is going to further complicate any cleanup effort later. Which means, the would not be doing that if there were any other water sources than seawater available in quantity.

  55. Much talk about the salt in the seawater, but what about other debris such as sand, shells, rocks, and other minerals; what could their effect be on nozzles, valves, pumps, seals, or other parts in the cooling system once it is brought back online?

  56. Is this to reading at 20km be believed? If so, please put into context.

    http://e.nikkei.com/e/fr/tnks/Nni20110322D22JF571.htm

    At least it has a rather big error in geography. It mentions Namie as the point of measure, but Namie is 10 km north of Fukushima Daiichi, not 20 km. It is indeed 20 km north of Fukushima Daini though.

    Considering that the highest dose rates measured outside of the 30 km perimeter have been 170 uSv/h (although about a week ago) and that the measurement point 46 actually 20 km away from Daiichi (and about 12 km north west of Namie) read 18 uSv/h at 1110 JST yesterday (a value between most other stations and the previous peak dose rate measuring points further north west), this new 160 uSv/h reading at Namie is not such a clear outlier.

    This is a dose rate that would usually require sheltering in place. Namie has been evacuated, so there should not be any concern for the general population and the emergency workers would be able to work there for about a month before exceeding even their normal (not extended rescue work) yearly doses.

  57. [unsupported hearsay. re-submit with reference/link please]

    just kidding ;-)
    MODERATOR
    re previous post:
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  58. Does the update from JAIF discredit the report from Kyodo news agency earlier of readings of 500 milliSv/hr?

    On CNN tv, although not yet on their website so no link, reports of black/grey smoke from No3 at 7.45 GMTWeds 23rd

  59. Recent private advice I have received is that almost all measured off-site contamination is I-131, so is a short-term (few weeks) and localised issue.

    That’s an interesting suggestion and compares as follows to fallout measurements collected from the highest fallout prefectures by MEXT (as of yesterday and I’m assuming these are peak values):
    Ibaraki, I-131: 85,000 MBq/km^2, Cs-137: 12,000 MBq/km^2, ratio 14% Cs
    Tokyo, I-131: 32,000 MBq/km^2, Cs-137: 5,300 MBq/km^2, ratio 16% Cs
    Saitama, I-131: 22,000 MBq/km^2, Cs-137: 1,600 MBq/km^2, ratio 7% Cs
    Tochigi, I-131: 25,000 MBq/km^2, Cs-137: 440 MBq/km^2, ratio 2% Cs

    So there is much variablity, but for total activity I-131 seems to be quite dominant. The I-131 related equivalent doses and protection factors are lower than Cs-137, sometimes by a factor of 10 though.

  60. Another comment from a friend of mine:

    A guy on the Energyfromthorium blog has just suggested that water radiolysis might be responsible for the explosions at Japan’s nuclear plants. To me it makes a lot more sense than does assuming that zirconium cladding though out the whole facility has gotten hot enough to chemically react with water.

    I’ve ball-parked the amount (cubic meters STP) of hydrogen that would be produced via radiolysis from the energy emitted by the fuel of a shut-down 2.2 GWth reactor as a function of time after shutdown assuming 1) a g factor of 0.5 molecule H2/100 ev and 2) that 10 % of the total energy reaches water:

    hrs joules heat cubic meters
    0.28 4.93E+10 6
    2.8 3.11E+11 36
    27.8 1.74E+12 202
    278 7.97E+12 927

  61. Does the update from JAIF discredit the report from Kyodo news agency earlier of readings of 500 milliSv/hr?

    Which update? There was no followup for the 500 mSv/h story from Kyodo, such as from where it was measured from. I don’t think JAIF has been keeping track of radiation measurements from the operational area within reach of the reactor buildings. The earlier confirmed peak was 400 mSv/h (don’t recall which day, but probably the first weekend).

    When workers return to spaces inside the reactor buildings and auxiliary buldings to do work, they could encounter higher radiation fields than ever before, if they happen to open doors leading to rooms with high levels of suspended particles, that then become airborne again with new airflow.

    At that time you usually don’t have time to stick around to take more accurate measurements or identify with accuracy where the radiation is coming from, but the priority is to evacuate the immediate surroundings ASAP.

  62. Kyodo expands on the today’s smoke story with worker evacuation and preliminary radiation data:

    Black smoke has been seen rising from the No. 3 reactor at Japan’s stricken nuclear power station, its operator Tokyo Electric Power Co. said Wednesday.

    TEPCO said workers evacuated from the Fukushima Daiichi plant’s No. 3 and No. 4 reactors after the smoke that was first reported around 4:20 p.m.

    It said no blaze was seen and that no other details are available yet.
    – –
    NEWS ADVISORY: No major change in radiation level at plant after black smoke: agency (17:18)

    MODERATOR
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  63. “It seems there is still have huge demand/supply disparity of clean or even fresh (low salt) water if they have really injected seawater to cool the external spent fuel storage pond, since decontaminating that will be costly and some damage to fuel rods and equipment might be expected.”

    One thing I have wondered since the beginning of this accident: since it was surely known to all of the nuclear engineers involved in design that, in the event of a complete loss of all normal core cooling mechanisms, the temperature and pressure would inevitably rise, and the pressure would eventually need to be regulated by venting steam to the outside in order to avoid failing the containment, then why not store a very large supply of reasonably fresh water on site for emergency use?

    Emergency cooling water needn’t be as pure as cooling water normally used in the core, and if that emergency water was stored well above the level of the reactor core, then gravity alone could be used to feed additional water into the cooling systems.

    An easily available backup supply of fresh water might have bought much needed time for the operators in this accident, time during which decay heat would be steadily dropping, just as it is now.

    Such a plan might have been quite expensive to implement, I suppose, but might have avoided the need to inject salt water into the system, with all the attendant risks.

    The CANDU reactors use very expensive heavy water in their cores, and so are able to use unenriched uranium as fuel. The heavy water is regarded as a one time expense.

  64. @David Kahana: what you write is correct, regarding the construction of a large clean water reservoir, but I wonder how it would be possible to keep it intact from a 10 meter wave and, even so, how use it with the pumps out of order.
    I don’t believe the engineers underestimate the quake or the tsunami (otherwise we would not have now a practically undamaged primary protection vessel): Japan suffered simply a really overdisized quake+tsunami, one you can seee once in a thousand years.
    and nevertheless the plant response has been superb, though not perfect, and all the damage resulted, as far as now, in some very stinky, very annoying end very quick dissolving farts.

  65. NEWS ADVISORY: No major change in radiation level at plant after black smoke: agency (17:18)

    It appears there has been a significant change about three hours JST before this “news advisory”. Whether that qualifies as “major” is another question though. The dose rate measured at the main gate jumped over 96 % in 20 minutes to 435.0 uSv/h, only to fall to a level of about 20 % higher half an hour later. Wind 1.6 m/s from east south east (from the “general direction” of the reactors).

    Source: TEPCO (sorry, only Japanese table)

  66. Radiation release modelers, who use the CTBTO measuring stations and their derived fallout dispersion models as well as national weather observations from different countries, have come to widely different initial conclusions about the released radioactive isotopes. Their systems and methods are designed to detect undeclared nuclear tests and calculate their yields and types of devices used.

    Usually they use the detected isotopes to confirm that a test has actually taken place and then the weather data (and seismic data) to ascertain where it has happened. What they are doing now, is runnig their models “backwards”, to come to a calculation of what kind of a release at a certainly known point in time and space would result in the detection of the given isotopes at the measuring stations.

    The most alarmist view is probably expressed by the Austrian Division for Data, Methods and Modelling Central Institute for Meteorology and Geodynamics of Wien raport:

    The total 4-day emission of 4×10^17 Bq is on the order of 20% of the total emissions of Iodine-131 that occurred during the Chernobyl accident.
    – –
    Taking this together, the source terms would be about 3×10^15 Bq during the first two days, and 3×10^16 during the second two-day period. In sum, this could amount to about 50% of the Chernobyl source term of Cesium-137.

    More caution is expressed in an earlier Science Magazine online article:

    “The wind is blowing everything out to sea, so they’ve been lucky so far,” says Andreas Stohl of the Norwegian Institute for Air Research.
    – –
    Based on the radionuclide data he has received so far, he believes none of the Fukushima reactors has experienced a full meltdown. Most of what has been detected have been volatile isotopes, including iodine, cesium, and xenon. A meltdown would have added less volatile elements to the mix, such as zirconium and barium, and these haven’t been detected in large quantities.

    Because of the source term uncertainties, all the dispersion models can do is give “qualitative advice on where the plume is going,” says Stohl.

  67. Okay, sorry for the confusion, I should have put qualifiers on those Bq figures.

    Let me try again. Radioactive decays:

    Chernobyl at peak release (1986) estimate 14 EBq
    Worlds oceans (continuously, always): 15000 EBq
    Chernobyl today: Maybe less than 0.1 EBq? Anyone know?
    Fukushima: 0.0003 EBq according to these rough assumptions:

    http://transport.nilu.no/products/fukushima

    Is this correct, 50000 times less peak release than Chernobyl at peak? Anyone has other estimates?

  68. re post by: William Fairholm, on 23 March 2011 at 4:20 AM said:

    Tokyo Fire Department has sprayed 3 times the pool capacity of unit 3 SFP. The water is leaking out and going somewhere, probably the ocean. Unless their aim is very bad and they don’t correct it. That they haven’t had to spray as much at unit 4 SFP also indicates they have a serious leak in the pool of unit 3.

    That would be the first thought that many would have, a reasonable one, and perhaps the conservatively safe conclusion although for whatever reason Jaczko appeared to disagree. Keep in mind, however, that we don’t know that either actually has a leak, let alone to what extent. Unless I’ve missed some instrumentation readings or something that way which clearly shows water depth for each pool anyhow.

    There is bound to be some percentage, I’d suspect even with excellent aim, some fairly large percentage that never makes it to the pools because of wind scatter, evaporation, plus every time they stop and start a stream, far more is lost than if it is one continuous stream, etc. But even if we assume that all of the stream makes it to the pools, we’ve no way to know if the added water isn’t just overflowing from the top – we don’t actually know how full or empty either of the pools were before they began spraying. Or for that matter just how full or empty either one is even now.

    So I’m thinking that all we really know is how much they’ve pumped out of each truck in the direction of each pool.

  69. Matt L, on 23 March 2011 at 8:36 PM said:

    >>>For goodness sake, that didn’t work….
    Just search for “Emergency work continues at Fukushima nuclear plant” on YT
    Or put watch?v=_YclU4_5Mdk in the address bar.>>>

    Too bad they took down the video, all you had to do was click on the youtube icon and go directly to the site and it worked just fine.

  70. @ Mattias
    It may be a mis-translation from the Japanese – it has happened before.
    However according to one of the charts(supplied by Prof Brook) posted on the BNC “Why I chose to stay in Tokyo”
    “No clinical conditions recognised for levels under 200millisieverts(full body exposure).”
    So I think you should supply a reference for the assertion that it would affect the thyroid.

  71. Pingback: 10+ days of crisis at the Fukushima Daiichi nuclear power plant – 22 March 2010 « BraveNewClimate

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  75. JohnG, on 23 March 2011 at 8:02 PM said:

    Guys, can anyone take a pic of this pic of no. 3 – it looks like there is a cement mixer in the lower right hand part of the image, perhaps two (one facing towards camera). Why would that be there, if that’s what it is? Given the fact that they have the cement pump there now, it seems quite a coincidence:

    When we pumped concrete at our place a couple of years ago, the pumps attached to a “socket” on the concrete mixer truck; rather than the concrete being poured into a hopper over an auger which is what I’ve seen more often. Or they may also need to pour some quickset to affect repairs to fuel pools.

  76. Folks..I think we should show a little more respect to regulatory safety limits rather than ‘manage’ or discount their relevance or credibility..its confusing to non experts reading this thread and might have some unintended and unfortunate side-effects..

  77. re various posts regarding dose limits, exceeding dose limits, etc. such as:

    So, the regulation levels have been excedeed but there is not an inmediate effect on people’s health. Why the reason of putting a safety level in the first place if it doesn’t matter when it’s surpassed?

    Please take a look at this paper – it gives a bit of history for how we’ve gotten into this situation where dose limits are almost certainly set far too low, including what some of the factors of conservatism are, and at what levels we actually can begin to correlate health effects to some sort of dose. I suspect the facts will shock some people.

    http://www.tinyvital.com/Misc/NukeLinearDoseEffectRelationship.htm

    People also have to understand what the limits actually are, in other words, what they are limiting, before flying off the handle. They are trying to limit your total annual dose through that particular pathway. ANNUAL dose. So if it’s an iodine limit for iodine in milk, then they assume you drink milk containing that limit amount EVERY DAY AT THAT LEVEL FOR AN ENTIRE YEAR. To set that limit, they most likely assume not only that you drink milk with that amount of activity every day for a year, but that your entire fluid intake every day is 100% milk (e.g., no other beverage or water, just milk – similarly, good chance that at the same time, the ‘safe limit’ set for iodine in water assumed you drank nothing but water every day for an entire year, and so on).

    Is there any chance that folks will be drinking sea water? NO. (well, ok, maybe a few swallows accidently by a few people at the beach this summer) But they’re checking it as if it were drinking water if I understand correctly. As to say, iodine levels in milk – I don’t recall what the actually level was, but say it was the one that was 126 times the limit – is there any chance that anyone will be drinking milk with that level of contamination for any length of time? No, because they’re already halting sales and checking to see that milk being sold isn’t contaminated. So even if you drank some of that milk with the higher level, at the levels they’ve found, it’s nowhere near high enough to equal what you’d get if you drank milk that was just at the limit, every day, for an entire year.

    There are so many factors thrown in to be super super safe just in case minuscule levels might perhaps maybe increase the chances of cancer 20 years down the road by even half a percent in a tiny percentage of the population so exposed…

    Anyhow, the paper is a useful one to read, and I think will help folks understand far better than I’m doing in this post.

  78. > they most likely assume … that your entire fluid
    > intake every day is 100% milk .. at the same time,
    > the ‘safe limit’ set for iodine in water assumed you
    > drank nothing but water

    [Citation needed]

    Personal observation — people who assume safety limits are nonsense often aren’t careful to follow them. I’ve seen this lead to sloppy handling of formaldehyde, mercury, pesticides, lead, and various other things, by people who were certain the rules couldn’t be necessary because they felt fine.

  79. BerGonella, on 23 March 2011 at 7:31 PM said:

    Japan suffered simply a really overdisized quake+tsunami, one you can seee once in a thousand years.

    While the earthquake was in the once in a thousand year category, the tsunami was not. Japan has suffered several larger tsunamis in just the last 100 yrs. The efficiency with which earthquake energy is converted into tsunami energy/wave height varies dramatically. See for instance the Hokkaido Tsunami of July 12, 1993, which was caused by a magnitude 7.8 earthquake.

    http://nctr.pmel.noaa.gov/okushiri_devastation.html

    For Nuclear Power Stations and for people in general it is the tsunami that causes the most damage and must be planned for.

  80. re post by: Red_Blue, on 23 March 2011 at 6:53 PM said:

    When workers return to spaces inside the reactor buildings and auxiliary buldings to do work, they could encounter higher radiation fields than ever before, if they happen to open doors leading to rooms with high levels of suspended particles, that then become airborne again with new airflow.

    At that time you usually don’t have time to stick around to take more accurate measurements or identify with accuracy where the radiation is coming from, but the priority is to evacuate the immediate surroundings ASAP.

    Red_Blue, from the way this is written it’s not clear if you were meaning just higher fields from kicked up particulates, or if you were referring to two scenarios that could account for higher fields (I assume the later, but just trying to clarify): 1) coming on an unexpectedly higher exposure rate because of shine penetrating into an area or originating in an area from facility damage, holes in walls, leaks, etc. which wouldn’t be at all surprising – actually it would be surprising if they weren’t encountering some of this, and/or 2) particulates being kicked up…

  81. I’m not sure that the frequency of equivalent height tsunami in Japan as a whole is the relevant metric.
    For instance in Hokkaido the sea floor may lead to very different affects than around Fukushima.
    The last tsunami this powerful in this particular area was around 1,000 years ago, so it seems to me that that may be the sense in which this is referred to a once in a thousand year event, although I would agree that that may put too optimistic a gloss on it.

  82. Hank, I agree that regulatory limits should be taken seriously, and I think the Japanese authorities are acting and giving advice based on those limits. But the point to address for us, with our luxury of distance, is whether there has been a health impact from the radioactive releases as they actually are. And to do that, some additional analysis of the reasons and assumptioins behind the regulations may be necessary. Unfortunately these are rarely easy to find, so we have to re-construct them to some extent. Rational Debate has not really done that, either, but their post is a start along that line, as I read it.

    For myself, I’d expect that the limits on milk would reflect the idea that the environment from which the milk was produced is also producing all your other food, and the remainder of your intake is also affected (although due to bioconcentration not as much as milk). I don’t know if the idea is that it is a continuing source or one-off contamination; in any case, such calculations are often based (like the nuclear worker exposure) on a years accumulation, which in itself is not rational, from the evidence of patients recovery (about two weeks) from radiotherapy.

  83. re post by: Red_Blue, on 23 March 2011 at 7:38 PM said:

    NEWS ADVISORY: No major change in radiation level at plant after black smoke: agency (17:18)

    It appears there has been a significant change about three hours JST before this “news advisory”. Whether that qualifies as “major” is another question though. The dose rate measured at the main gate jumped over 96 % in 20 minutes to 435.0 uSv/h, only to fall to a level of about 20 % higher half an hour later. Wind 1.6 m/s from east south east (from the “general direction” of the reactors).

    Source: TEPCO (sorry, only Japanese table)

    Anyone who wants to see an english version might want to try google translate – formatting is a bit wonky for me using firefox, but it may come out better with other browsers, or on different screen resolutions, etc. If you just see “Translating” but no table of data, click on that blue translating and give it a moment or two….

    http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=ja&tl=en&u=http%3A%2F%2Fwww.tepco.co.jp%2Fnu%2Fmonitoring%2F11032307.pdf

  84. Rational Debate, on 23 March 2011 at 9:37 PM said:

    There is bound to be some percentage, I’d suspect even with excellent aim, some fairly large percentage that never makes it to the pools because of wind scatter, evaporation, plus every time they stop and start a stream, far more is lost than if it is one continuous stream, etc.

    I’ve posted several reasons to suspect a leak in SPF 3. Look back at several of my posts on the matter. They continue to spray water into it, including today. I’m not saying a leak is confirmed, but that it seems to be a likely interpretation of their actions.

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300850463P.pdf

  85. I’ve managed to pull the data for the Google translation:
    Page 1
    Measured by monitoring car status – Exhibit Fukushima Daiichi Nuclear Power Station
    Sun Measurement: March 23
    Measurement time
    Measurement Location
    Γ-ray
    Neutron radiation
    Wind direction
    Wind speed (m / s)
    3:00 pm
    Portal
    265.4 μSv / h 0.01 μSv / h under
    Northeast
    1.6
    50 minutes at 2:00 pm
    Portal
    267.8 μSv / h 0.01 μSv / h under
    East-southeast
    1.7
    2 at 1:40 pm
    Portal
    309.7 μSv / h 0.01 μSv / h under
    East-southeast
    1.6
    2:30 pm
    Portal
    288.7 μSv / h 0.01 μSv / h under
    East
    0.9
    20 minutes at 2:00 pm
    Portal
    435.0 μSv / h 0.01 μSv / h under
    East-southeast
    1.6
    10 minutes at 2:00 pm
    Portal
    231.1 μSv / h 0.01 μSv / h under
    Northeast
    1.0
    2:00 pm
    Portal
    222.4 μSv / h 0.01 μSv / h under
    North
    1.4
    50 mins 1:00 pm
    Portal
    222.7 μSv / h 0.01 μSv / h under
    Northwest
    1.2
    At 1:40 pm
    Portal
    223.7 μSv / h 0.01 μSv / h under
    Northeast
    1.3
    1:30 pm
    Portal
    224.1 μSv / h 0.01 μSv / h under
    North
    1.5
    At 1:20 pm
    Portal
    225.7 μSv / h 0.01 μSv / h under
    North
    2.0
    1:10 pm
    Portal
    224.8 μSv / h 0.01 μSv / h under
    East-southeast
    1.9
    1:00 pm
    Portal
    225.4 μSv / h 0.01 μSv / h under
    East
    1.2
    50 mins 0:00 pm
    Portal
    224.8 μSv / h 0.01 μSv / h under
    East
    1.4
    0 at 1:40 pm
    Portal
    224.7 μSv / h 0.01 μSv / h under
    West-northwest
    1.5
    12:30 pm
    Portal
    224.9 μSv / h 0.01 μSv / h under
    West
    1.6
    20:00 pm minutes
    Portal
    224.8 μSv / h 0.01 μSv / h under
    West
    1.6
    10:00 pm minutes
    Portal
    226.0 μSv / h 0.01 μSv / h under
    North-northeast
    2.6
    12:00 noon
    Portal
    225.2 μSv / h 0.01 μSv / h under
    North-northwest
    1.6
    At 11:50 am
    Portal
    226.3 μSv / h 0.01 μSv / h under
    North
    1.5
    11 at 1:40 am
    Portal
    225.7 μSv / h 0.01 μSv / h under
    North
    2.2
    11:30 am
    Portal
    226.3 μSv / h 0.01 μSv / h under
    North-northeast
    2.1
    Minutes 20:11 am
    Portal
    226.8 μSv / h 0.01 μSv / h under
    North-northeast
    2.5
    Minutes 10:11 am
    Portal
    226.8 μSv / h 0.01 μSv / h under
    North
    2.6
    11:00 am
    Portal
    227.0 μSv / h 0.01 μSv / h under
    North-northwest
    3.0
    10:00 50 mins
    Portal
    227.2 μSv / h 0.01 μSv / h under
    North
    3.1
    At 10:40 am
    Portal
    227.1 μSv / h 0.01 μSv / h under
    North-northwest
    2.9
    10:30 am
    Portal
    227.3 μSv / h 0.01 μSv / h under
    North
    2.9
    Minutes 20:10 am
    Portal
    227.2 μSv / h 0.01 μSv / h under
    North-northeast
    3.1
    At 10 am
    Portal
    227.7 μSv / h 0.01 μSv / h under
    North
    2.7
    10:00 am
    Portal
    211.4 μSv / h 0.01 μSv / h under
    North
    2.6
    At 9:50 am
    Portal
    227.6 μSv / h 0.01 μSv / h under
    North-northeast
    3.1
    9 at 1:40 am
    Portal
    228.6 μSv / h 0.01 μSv / h under
    North-northeast
    2.5
    9:30 am
    Portal
    226.9 μSv / h 0.01 μSv / h under
    North
    3.4
    At 9:20 am
    Portal
    227.6 μSv / h 0.01 μSv / h under
    North
    2.9
    Minutes 10:09 am
    Portal
    228.7 μSv / h 0.01 μSv / h under
    North-northeast
    3.3
    9:00 am
    Portal
    229.1 μSv / h 0.01 μSv / h under
    North
    3.5
    At 8:50 am
    Portal
    229.1 μSv / h 0.01 μSv / h under
    North-northwest
    3.1
    40 minutes at 8:00 am
    Portal
    229.1 μSv / h 0.01 μSv / h under
    North-northwest
    4.4
    8:30 am
    Portal
    229.4 μSv / h 0.01 μSv / h under
    North-northwest
    3.9
    20 minutes at 8:00 am
    Portal
    229.2 μSv / h 0.01 μSv / h under
    North-northwest
    3.5
    Minutes 10:08 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North
    3.2
    8:00 am
    Portal
    229.4 μSv / h 0.01 μSv / h under
    North
    3.1
    7:00 AM 50 minutes
    Portal
    229.3 μSv / h 0.01 μSv / h under
    North
    2.5
    7 at 1:40 am
    Portal
    229.0 μSv / h 0.01 μSv / h under
    North
    3.0
    7:30 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North-northwest
    2.8
    Minutes 20:07 am
    Portal
    229.3 μSv / h 0.01 μSv / h under
    North-northwest
    2.6
    Minutes 10:07 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North-northwest
    2.4
    7:00 am
    Portal
    229.3 μSv / h 0.01 μSv / h under
    North-northwest
    2.7
    50 minutes at 6:00 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North-northwest
    2.1
    6 at 1:40 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    Northwest
    2.4
    6:30 am
    Portal
    229.6 μSv / h 0.01 μSv / h under
    North-northwest
    2.7
    At 6:20 am
    Portal
    229.4 μSv / h 0.01 μSv / h under
    Northwest
    2.6
    At 6:10 am
    Portal
    229.6 μSv / h 0.01 μSv / h under
    North-northwest
    2.5
    6:00 am
    Portal
    229.6 μSv / h 0.01 μSv / h under
    North-northwest
    2.5
    At 5:50 am
    Portal
    229.7 μSv / h 0.01 μSv / h under
    Northwest
    2.4
    5 at 1:40 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North-northwest
    2.2
    5:30 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    Northwest
    2.1
    5:20 am
    Portal
    229.6 μSv / h 0.01 μSv / h under
    North-northwest
    2.2
    Minutes 10:05 am
    Portal
    229.3 μSv / h 0.01 μSv / h under
    North
    1.8
    Page 2
    Measurement time
    Measurement Location
    Γ-ray
    Neutron radiation
    Wind direction
    Wind speed (m / s)
    5:00 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North
    2.1
    At 4:50 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North
    2.1
    4 at 1:40 am
    Portal
    229.5 μSv / h 0.01 μSv / h under
    North-northwest
    1.8
    4:30 am
    Portal
    229.3 μSv / h 0.01 μSv / h under
    Northwest
    1.7
    Minutes 20:04 am
    Portal
    229.4 μSv / h 0.01 μSv / h under
    North-northwest
    2.4
    Minutes 10:04 am
    Portal
    229.1 μSv / h 0.01 μSv / h under
    Northwest
    2.1
    4:00 am
    Portal
    229.1 μSv / h 0.01 μSv / h under
    North
    2.1
    3:00 AM 50 minutes
    Portal
    229.0 μSv / h 0.01 μSv / h under
    Northwest
    2.2
    At 1:40 am
    Portal
    228.8 μSv / h 0.01 μSv / h under
    North
    2.6
    3:30 am
    Portal
    228.8 μSv / h 0.01 μSv / h under
    North-northwest
    2.3
    Minutes 20:03 am
    Portal
    228.7 μSv / h 0.01 μSv / h under
    North-northwest
    2.3
    At 3:10 am
    Portal
    228.5 μSv / h 0.01 μSv / h under
    North
    2.2
    3:00 am
    Portal
    227.6 μSv / h 0.01 μSv / h under
    North-northwest
    2.9
    50 minutes at 2:00 am
    Portal
    227.3 μSv / h 0.01 μSv / h under
    Northwest
    3.1
    2 at 1:40 am
    Portal
    227.2 μSv / h 0.01 μSv / h under
    North
    3.0
    2:30 am
    Portal
    227.1 μSv / h 0.01 μSv / h under
    North
    2.9
    Minutes 20:02 am
    Portal
    227.1 μSv / h 0.01 μSv / h under
    Northwest
    2.8
    Minutes 10:02 am
    Portal
    226.9 μSv / h 0.01 μSv / h under
    North
    2.8
    2:00 am
    Portal
    226.7 μSv / h 0.01 μSv / h under
    North
    3.2
    1:00 AM 50 minutes
    Portal
    226.7 μSv / h 0.01 μSv / h under
    North
    3.3
    At 1:40 am
    Portal
    226.8 μSv / h 0.01 μSv / h under
    North-northwest
    3.4
    1:30 am
    Portal
    226.8 μSv / h 0.01 μSv / h under
    North-northwest
    4.2
    At 1:20 am
    Portal
    227.2 μSv / h 0.01 μSv / h under
    North-northwest
    6.0
    1:10 am
    Portal
    227.4 μSv / h 0.01 μSv / h under
    Northeast
    6.5
    1:00 am
    Portal
    227.5 μSv / h 0.01 μSv / h under
    North
    2.4
    50 minutes midnight
    Portal
    229.4 μSv / h 0.01 μSv / h under
    Northeast
    5.5
    0 at 1:40 am
    Portal
    230.1 μSv / h 0.01 μSv / h under
    Northwest
    2.5
    12:30 am
    Portal
    231.6 μSv / h 0.01 μSv / h under
    West
    4.3
    20:00 am-minute
    Portal
    232.3 μSv / h 0.01 μSv / h under
    North-northwest
    2.6
    Minutes 10:00 am
    Portal
    233.3 μSv / h 0.01 μSv / h under
    Northwest
    1.8
    12:00 midnight
    Portal
    233.4 μSv / h 0.01 μSv / h under
    Northwest
    1.8

  86. Just speculating on water issues that others have brought up. First, for the idea of trucking in fresh water – I doubt they could bring in enough volume, but am not at all certain of that. Even so, I gather that getting through on the roads can still be quite difficult – recall the report saying that they had decided to use the concrete pumper on the 18th, but road conditions and training delayed getting the truck there until today… no idea how much of that delay was roads.

    Have been listening to NHK Tv a fair amount the last few days, however, and they report massive problems throughout the area getting water for people both because of supply problems and road problems. Also problems at least in some areas with large trucks literally running out of gas/diesel on the roads and winding up blocking the roads because they’re having such troubles getting petrol also. Add to that reports of suppliers/vendors/drivers refusing to go to areas that are still well outside of the exclusion zone for fear of radiation…

    As to the idea of an uphill gravity fed storage pond – keep in mind that you’d have to be able to site one safely, both in terms of any reasonable volume, but also such that it wouldn’t be a flood risk for the power station below in case of, ya, earthquake, or dam break, or terrorist attack, etc. Then as others have mentioned I believe, whatever caused a loss of both off site power and diesel generator power is awfully likely to rupture any supply pipes that you’d have going from the pond down into the plant…

    I suspect this is one of those ideas that sounds good, but just doesn’t cut it from a number of standpoints once the engineering/design begins to be seriously considered.

  87. Anyone have any theories on what keeps smoking on 3? My guess is debris falls into the pool, perhaps on exposed rods and goes up in smoke? assumption based upon the massive damage to the roof and walls of that building… can’t seem to come up with any other logical reason why that building would smoke from time to time, and it sure does seem as though this is smoke and not just steam that the media has been calling smoke ias has been seen in the past…

  88. re post by: Hank Roberts, on 24 March 2011 at 12:06 AM said:

    > they most likely assume … that your entire fluid
    > intake every day is 100% milk .. at the same time,
    > the ‘safe limit’ set for iodine in water assumed you
    > drank nothing but water

    [Citation needed]

    I don’t have one handy – which is why I said “most likely” because I have seen and dealt with these calculations in the USA, and although years ago done complete pathway exposure analysis to determine the most at risk and the most exposed hypothetical member of the public, etc. It appears that at least for some of these limits, Japan’s are even lower than ours, and ours are extremely conservatively safe.

    Personal observation — people who assume safety limits are nonsense often aren’t careful to follow them. I’ve seen this lead to sloppy handling of formaldehyde, mercury, pesticides, lead, and various other things, by people who were certain the rules couldn’t be necessary because they felt fine.

    NO ONE should EVER assume that safety level are nonesense, and that wasn’t at all what I was trying toconvey. I was trying, perhaps not very well, to give at least the beginning of an understanding for what these safety limits are based on, and why it does make sense and is not unreasonable for the Japanese Government to say that eating or drinking certain foodstuff that are above the ‘safety limits’ is not harmful at this time, or statements to that effect.

    Why it is reasonable in this case to actually trust that what the government is telling you is safe, really is. In other words, Hank, why it seems to me that people ought to follow the Japanese Government’s safety directions as they are given for each situation.

  89. Neutron beam observed 13 times at crippled Fukushima nuke plant

    TOKYO, March 23, Kyodo
    Tokyo Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of the Fukushima Daiichi nuclear plant after it was crippled by the massive March 11 quake-tsunami disaster.
    TEPCO, the operator of the nuclear plant, said the neutron beam measured about 1.5 kilometers southwest of the plant’s No. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour and that this is not a dangerous level.
    The utility firm said it will measure uranium and plutonium, which could emit a neutron beam, as well.

    http://english.kyodonews.jp/news/2011/03/80539.html

  90. David Martin, on 24 March 2011 at 12:54 AM said:

    I’m not sure that the frequency of equivalent height tsunami in Japan as a whole is the relevant metric.

    There are NPS all around Japan. I don’t know if the design criteria has been different for those areas that have been subjected to historic tsunamis, but I would sure hope so.

  91. What I am trying somewhat clumsily to express is that they may be running the risks for a specific location to come up with ‘once in a thousand year’ characterisations.
    When you have 54 reactors at several sites though the more relevant metric would seem to be a much larger area, possibly the whole or most of Japan.

  92. > they most likely assume … that your entire fluid
    > intake every day is 100% milk .. at the same time,
    > the ‘safe limit’ set for iodine in water assumed you
    > drank nothing but water

    [Citation needed]

    I mean, I’m assuming that you want a clickable link? In general, tho, ICRP 30, 10 CRF 20, and several textbooks – for example I imagine that the book “Introduction to health physics” by Herman Cember, Thomas Edward Johnson probably covers it reasonably well, although this is a newer edition than when Cember was one of the key texts back years ago.

  93. This is an interesting list of the largest Tsunamis, of which Japan has more than it’s fair share:

    http://en.wikipedia.org/wiki/Historic_tsunamis#1933:_Showa_Sanriku.2C_Japan_.28.E6.98.AD.E5.92.8C.E4.B8.89.E9.99.B8.E5.9C.B0.E9.9C.87.29

    It was a sobering read for me. If the data is accurate this was not a once in a thousand year even, or even once in a hundred year event. It would take some study of where they occurred and where the nuclear plants are sited.

  94. Rational, no one person drinks entirely milk _and_ entirely water–agreed. Not sure what point you’re trying to make about that. The limits are per isotope, not per all isotopes combined for one person.

  95. In case it hasn’t already been posted or some folks didn’t catch it, here is an interview with a radiation epidemiologist & Health Physics Society member (e.g., radiological safety) he’s from Vanderbilt University, regarding the potential health effects & how much to worry or not worry about radiation levels & contamination being seen both onsite & offsite at Fukushimi from a few days ago, 3/20/11. http://www.youtube.com/watch?v=uvT5EDU5vTc&feature=email

  96. NR99, on 24 March 2011 at 2:38 AM said:
    This is an interesting list of the largest Tsunamis, of which Japan has more than it’s fair share:

    Yes I almost linked to this article, but I was trying to find a link with just Japanese tsunamis and so just linked to a recent large tsunami. Japan is the most tsunami prone area in the world. They even get hit by tsunamis that are created on the other side of the Pacific on a regular basis, though they are no where near as big as locally generated ones. Very appropriate that we are using the Japanese word for this phenomenon.

  97. William,

    It would be interesting to read the Tsunami analysis associated with the plant site surveys and filings.

    I came to two conclusions, strictly from the Wikipedia article….

    1. The existing 5.7 meter Fukushima wall is “not tall enough”.

    2. No conceivable wall is tall enough :-(

    There were reports in that link talking about Tsunamis up to 300 feet tall, and several at 100 foot.

    I copied below the 1933 Tsunami discussion, where a 10 meter wall was built that stopped the 1960 Chilean event but failed in this recent event. That 10 meter wall was the largest I could find in a quick search last night.

    It’s a daunting challenge. It may be a risk Japan cannot mitigate but I am a lay person so I mention this just for further research. And that’s why I think the site surveys would be interesting reading…

    This was discussed in the other discussion thread but since it was brought up here….

    “1933: Showa Sanriku, Japan (昭和三陸地震)
    Main article: 1933 Sanriku earthquake
    On March 3, 1933, the Sanriku coast of northeastern Honshū, Japan which had already suffered a devastating tsunami in 1896 (see above) was again stuck by tsunami waves as a result of an offshore magnitude 8.1 earthquake. The quake destroyed about 5,000 homes and killed 3,068 people, the vast majority as a result of tsunami waves. Especially hard hit was the coastal village of Taro (now part of Miyako city) in Iwate Prefecture, which lost 42% of its total population and 98% of its buildings. Taro is now protected by an enormous tsunami wall, currently 10 meters in height and over 2 kilometers long. The original wall, constructed in 1958, saved Taro from destruction of the 1960 Chilean tsunami (see below). However it failed to protect Taro from the 2011 Tōhoku earthquake and tsunami which inundated the village with 12-15 meters of water.[22]”
    MODERATOR
    This post and others about the tsumai really belongs in the Open Thread.This occurred overnight (in Australia). However, as I am unable to switch them to the other thread I would have to delete several by various people and that seems unfair given that there was no moderation overnight advising them to switch threads. This is a warning to all commenters,however, if it happens again I will delete all such comments and
    you will have to re-post.PLEASE SWITCH TO THE OPEN THREAD FOR THESE DISCUSSIONS ON TSUNAMI FREQUENCY/HEIGHT ETC.

  98. This was the impressive one:
    ‘Tsunamis were the main cause of death for Japan’s worst-ever volcanic disaster, due to an eruption of Mount Unzen in Nagasaki Prefecture, Kyūshū, Japan. It began towards the end of 1791 as a series of earthquakes on the western flank of Mount Unzen which gradually moved towards Fugen-daké, one of Mount Unzen’s peaks. In February 1792, Fugen-daké started to erupt, triggering a lava flow which continued for two months. Meanwhile, the earthquakes continued, shifting nearer to the city of Shimabara. On the night of 21 May, two large earthquakes were followed by a collapse of the eastern flank of Mount Unzen’s Mayuyama dome, causing an avalanche which swept through Shimabara and into Ariake Bay, triggering a tsunami. It is not known to this day whether the collapse occurred as a result of an eruption of the dome or as a result of the earthquakes. The tsunami struck Higo Province on the other side of Ariake Bay before bouncing back and hitting Shimabara again. Out of an estimated total of 15,000 fatalities, around 5,000 is thought to have been killed by the landslide, around 5,000 by the tsunami across the bay in Higo Province, and a further 5,000 by the tsunami returning to strike Shimabara. The waves reached a height of 330 ft, classing this tsunami as a small megatsunami.’

    Perhaps the best you can try for in those sort of circumstances is some kind of relatively graceful failure.
    With a lot of these events though some level of radioactive release as long as it does not reach excessive proportions is really the least of your worries though.
    The death toll from this tsunami looks like being 22,000 or so, so radioactive releases are likely to have minimal consequences comparatively.

  99. 1) coming on an unexpectedly higher exposure rate because of shine penetrating into an area or originating in an area from facility damage, holes in walls, leaks, etc. which wouldn’t be at all surprising – actually it would be surprising if they weren’t encountering some of this, and/or 2) particulates being kicked up…

    I would expect particulate migration to be a more significant threat and the simple reason is that your dosimeter is going to give a laud audible alert (and here I assume that the point man in every team is wearing one of the electronic plan personnel dosimeters, even if rest of the team has only rescue worker color badges) once the dose rate exceeds the preset alert level, which will happen immediately from direct gamma from a high radiation room. So you will then have the ability to back down righ away and avoid further high dose.

    But it at the moment of opening the door, there was a slight overpressure and you got sprayed with high activity particles, now you will be “lit like a christmas tree” so to speak and backing down no longer will help enough, instead you must get your suit surfaces and especially boots decontaminated with a water spray ASAP to get the dose rate down.

    That’s why you’re supposed to scan (closely) around the seals with a GM or proportional counter before opening any door. Proper airlocks also have pressure gauges and measurement ports with valves that you can use to check the atmosphere on the other side before entering. There aren’t many of those in a normal plant though.

  100. Regarding the radiation data from the site. What I really want to know is why they have stopped measuring data at the office site. This was the location which provided a lot of data between the 17th and 21st of March, and values there were always much higher than at the gate, I presume in large part because this location is only 0.5km from reactors, as opposed to the gate which is around 1km away.

    Anyway there have been no published measurements from this location since 16:10 JST on the 21st, when the reading there had got down to 2015 microsieverts/h. The general pattern from this location was of declining levels, down from 3786 at 09:30 on the 17th for example, but with occasional spikes which caused this declining trend to be less rapid than it looked like it would have been.

    When they switched locations it looks very much like it may have been in response to the black smoke evacuation event, and the location they switched to saw rapidly fluctuating levels when readings started coming from there, some half an hour after readings from the office building ceased, before returning to the steady decline that has often been the norm for readings at various points at the plant. This makes me very curious at to what the levels at the office site would have been around that time, or at any time since.

  101. When a full analysis of this event is made, there will have to be consideration of what happened at the other nuclear power stations that were hit by the tsunami. From the map of Japan provided at the end of the JAIF reactor status reports, there were 14 nuclear reactors, hit by the tsunami. Eleven were operating at the time of the quake.

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300882515P.pdf

    We already know that Fukushima Dai-ni suffered similar problems with their backup power and/or pumps. Three of their reactors have received an INES rating of 3. They did not lose outside power and were therefore able to deal with any problems they had. Why did Dai-ichi lose outside power while Dai-ni did not? The tsunami height and earthquake distance were similar. Was this the result of Dai-ni being more recent and therefore site selection more strict, outside power lines more robust or just luck?

    Now Onagawa was much closer to the earthquake and suffered no ill effects (except a turbine fire, see wiki article). This seems to have been helped by site selection as the plant is built at a higher elevation and has hills behind it that would stop the tsunami from coming around from behind. The transmission lines also go up the hills behind the plant and would have been protected from the tsunami. (The height measurement were linked to by someone on a previous day. I am assuming that is true).

    http://en.wikipedia.org/wiki/Onagawa_Nuclear_Power_Plant

    Now was this site selection done for the purpose of protecting against a tsunami or for other reasons (e.g. not useful for other purposes) or both. If the latter then site selection could be considered somewhat “lucky”. Again this station is newer than Fukushima Dai-ichi and would have had stricter criteria.

    The same chain of reasoning applies to the one reactor at Tokai Dai-ni.

    To sum up this event will have to be analysed, not just with what happened, but what reasonable probability was there for many more reactors being in a similar situation to those at Fukushima Dai-ichi. It seems to me that site selection, station design and “luck”, good and bad have resulted in the current situation. For example it was lucky that the 3 reactors that were not running were at Fukushima Dai-ichi. It was unlucky that unit 1 there was just about to be decommissioned, but the earthquake struck before it could be.

  102. Oh and just to clarify which sites and data I was talking about, at the following site that Im sure many of you are already aware of due to its nice graphs, the location I am moaning about not getting data on anymore is described here as ‘North Building’, and the values we are getting recently are from ‘Plant Main Gate’. The little spike you see on 21st at Plant Main Gate is what I would love to have seen from North Building.

    Can anybody say more about the neutron beam stuff which as far as I know so far has only been discussed in one Kyodo news story?

  103. Oh and just to clarify which sites and data I was talking about, at the following site that Im sure many of you are already aware of due to its nice graphs, the location I am moaning about not getting data on anymore is described here as ‘North Building’, and the values we are getting recently are from ‘Plant Main Gate’. The little spike you see on 21st at Plant Main Gate is what I would love to have seen from North Building.

    That data comes from a mobile unit (a car) and it moves irregularily between locations that at one point used to be associated with the fixed monitoring posts (since these were out of power for a while at the start of the crisis), but later have moved between locations closer to the reactors. The fixed monitoring posts are all at the plant perimeter.

    There has also been some confusion in the media and other sources between the named locations of where the car has been.

    Actually, the “North Building” means _north of_ the main administrative/office building. Also, when referring to gates, there are 2 gates, the main gate which is south west and the west gate which is west of the reactors.

    Please find the locations (within about 50 m) of where the measurements of last days have been taken on Google Map:

    Main gate
    North of office building

  104. Steve Elbows, on 24 March 2011 at 4:25 AM said:

    Can anybody say more about the neutron beam stuff which as far as I know so far has only been discussed in one Kyodo news story?

    I think the Kyodo article you referred to is this one.

    http://english.kyodonews.jp/news/2011/03/80539.html

    I do not understand this article. The only thing that could be emitting neutrons would be from the spontaneous fission of plutonium 240. See neutrons per gram in wiki article. That would indicate that some plutonium has been released. That should be easy to determine. The alpha radiation would be much, much, much higher from this source. Dangerously high.

  105. I do not understand this article. The only thing that could be emitting neutrons would be from the spontaneous fission of plutonium 240.

    There are also other nuclides with small spontaneous fission rates. Cf-152 actually has much higher spontaneous fission than plutonium, but is only a result of a very long decay chain of U-238 (that goes through Pu-140 as well).

    IAEA has not measure alpha decays with their istruments spesifically designed for it, but so far TEPCO has not reported any attempted alpha measurements from the site. The monitoring car has a neutron counter, but its reading has been converted to 0.01 uSv/h for every measurement, which I believe is consistent with neutron flux from outer space at ground level. Or it could mean that the detection limit is that much and they list it as the upper bound.

    I’m not sure what the Kyodo story is sourcing, it could be that they mean an increase of 0.01-0.02 uSv/h (or rather 10-20 nGy/h) from the detection level of background, or they may refer to these measurements directly.

    I don’t think those are conclusive either way, at least not until we get more data about what exactly was measured and where.

  106. OK, so Tepco’s latest press release (110323e3.pdf) shows some tellurium detected.

    http://www.osti.gov/bridge/product.biblio.jsp?osti_id=6188157
    “Fission product release tests at Oak Ridge National Laboratory (ORNL) have provided new experimental data that help characterize the behavior of tellurium under severe light-water reactor (LWR) accident conditions. The release of tellurium from the fuel rods is dependent upon the rate and extent of cladding oxidation. Tellurium has been found to be considerably retained by metallic Zircaloy cladding at test temperatures up to 1975/sup 0/C. The results indicate that the tellurium is bound by the Zircaloy cladding as zirconium telluride, but once the available zirconium metal is oxidized by the steam, tellurium is released in favor of continued zirconium oxide formation. The collection behavior of the released tellurium indicates that it is probably released from the fuel rods as SnTe and CsTe, rather than as elemental tellurium.”

  107. re post by: Red_Blue, on 24 March 2011 at 4:16 AM

    You are absolutely right of course. I wasn’t thinking beyond the ‘what could cause workers to run into unexpectedly higher dose rates’ side of things – and obviously just as you explained that ain’t the half of it, and getting painted so to speak with particulates that you have to get off quickly would be the far more serious situation.

  108. I realize that this is a day old but I haven’t seen any mention of it on this site

    He gave no more details, but a TEPCO executive vice president, Sakae Muto, said the core of reactor No.1 was now a worry with its temperature at 380-390 Celsius (715-735 Fahrenheit).

    “We need to strive to bring that down a bit,” Muto told a news conference, adding that the reactor was built to run at a temperature of 302 C (575 F).

    http://wallstreetpit.com/68105-fukushimas-reactor-1-core-reaches-400-degrees-celsius

    This retired chemical engineer went to his trusty Perry’s steam tables and determined that this means the equilibrium pressure inside the reactor is > than the critical pressure of steam (from memory ~375 C and 220 bar). Design operating conditions are stated to be 302 deg C which is ~170 bar (2500 psi).

    If the reported 400 deg C temp is correct I have to ask how they are injecting water against an internal pressure > 3000 psi and what is the design pressure for the reactor in the first place?

  109. What I can’t get my mind around is the ECCS loss in unit’s 1 & 3. In both, iirc, ECCS was lost roughly an hour after the tsunami, while it performed for a few days at unit 2 (which I would have thought more likely).

    The scientificamerican article someone else linked to above hypothesized that it failed because the reactor pressure vessel internal pressure got too high. I’m having a hard time buying that, but don’t have the BWR systems background to know.

    Can anyone here with some knowledge of the system speculate on what could cause the ECCS failure? The high pressure injection system and/or residual heat removal both should have worked for awhile from decay heat steam pressure alone…

    So – any knowledge of just what max pressure they are likely to function up to? Plus, mechanism that could cause a pressure increase that way in just an hour??
    – and how long should ECCS be able to function in a scrammed reactor before the water temp becomes too high for them to be useful any more? I would have thought that would be a day or two at least, wouldn’t it?

    Info on these issues? Thoughts? Speculation?

  110. I has been 45 years, but as I recall, above the critical point there are no liquid or vapour phases so the fuel bundles are not partially submerged in water. Rather, they 100% immersed in a super critical fluid.

  111. Red_Blue, on 24 March 2011 at 5:38 AM said:

    which I believe is consistent with neutron flux from outer space at ground level.

    I thought of that, but then they would measure it everywhere. At sealevel the neutron component of cosmic rays is getting low. I tried looking for an article on how it varies with altitude. The reference I found was to 1964 and not on line. Doesn’t really matter. If an actinide was the source, the alpha radiation would be much higher. All the actinides would move together, so doesn’t really matter what would be producing spontaneous fission neutrons. I choose Pu 240, because there is a lot of it in used fuel and it has a “short” Sf half-life. Still doesn’t make sense to me.

  112. re post by: Hank Roberts, on 24 March 2011 at 6:11 AM

    Hi Hank,

    No, hadn’t searched specifically at NRC, just googled in general a bit where of course I got loads of worthless or basic stuff but little that was technical enough. You’re right I ought to try NRC.

    I was hoping that someone here might know enough to help me understand the system interplay better specifically under the Fukushima conditions. The high pressure systems would be first line of defense (unless I”m missing something, which is entirely possible), and have what appears to be a major discrepancy between rapid (~1 hr.) failures at both until 1 & 3, where it seems to have lasted a few days in unit 2…. so I’ve really been scratching my head over just what could account for the difference there.

    The difference in loss of offsite power between Dai-ini and Dai-ichi, that I can easily envision being a function of transmission system failures that might have had everything to do with the quake and/or tsunami and little or nothing to do with the plants themselves – and it may turn out to be far harder to pin down whether any changes in the incoming lines, transformers, etc. could have avoided the failure. Obviously it has to be looked into rigorously even so. But even if there is loss of offsite power, they should have been able to fall back to the ECCS…

    So right or wrong I’m stuck at that point, wanting to understand that system a little better along with ideally getting some input on possible causes of failure in the high pressure turbine run side of the ECCS from folks who know the systems a bit.

  113. I thought of that, but then they would measure it everywhere. At sealevel the neutron component of cosmic rays is getting low.

    I think they are measuring it everywhere, just that because it hasn’t changed anywhere else (or inside the plant perimeter, at least until now), it has not been reported.

    The perimeter fixed sensors also have neutron counters, but these might be either not detecting any or alternatively the neutron counters are offline. I believe they are still operating on battery power. Recently TEPCO has only releases the numbers from MP4, which is about 500 north of the “west gate” and read about 10 uSv/h. So if there were any neutron emissions barely detectable somewhere much closer to the reactors, none would be detected here. The neutron detection value is listed as “–” as well as wind direction and speed data, indicating that it’s not available for unknown reasons.

    If an actinide was the source, the alpha radiation would be much higher.

    That’s the problem, we have not heard of anything about any alpha measurements, either from TEPCO or anyone else from the plant area. So we cannot state, that because there has been no high alpha counts, there could not be neutrons from plutonium or other fuel pellet heavy elements.

  114. Red_Blue, on 24 March 2011 at 7:11 AM said:

    That’s the problem, we have not heard of anything about any alpha measurements

    I guess I should have been clearer. They are measuring ionizing radiation levels. With a measureable neutron level from sponateous fission the level from the alpha radiation would be very high. They do not have to specifically look for it.

  115. Red_Blue, I think the present MP-4 readings you are looking at might be from the other nuclear plant, Daini.

    Readings at Daiichi are still coming from the gatepost, 216.6 uSv/h at 03:00

    And thanks very much for your earlier post in answer to my monitoring point questions. I was mostly wondering what lies behind the decision to start publishing data from a different location, eg why does the car move location, is it by choice of because some parts of site get evacuated, has some monitoring equipment broken, or some other explanation.

    And thanks to everyone for the thoughts on the neutron stuff, I guess we need more information.

  116. “DOE/NNSA release rad data from Japan

    The Dept. of Energy and its sub-unit, the National Nuclear Security Administration, have released their first batch of data from radiation monitoring around the Fukushima Daiichi nuclear power plant in Japan. It’s presented via a series of slides on the agency’s web site. Here’s the link.

    “Since arriving in Japan, NNSA teams have collected and analyzed data gathered from more than 40 hours of flights aboard Department of Defense aircraft and thousands of ground monitoring points,” the press statement said.

    Info on the DOE slides said that nearly all the elevated radiation reading were within a 25 mile radius of the Daiichi plant site. It also said all readings in this plot were below 0.03 rem per hour, which was characterized as a low level.

    “Measurements also show an area of greater radiation extending northwest from the accident. This area may be of interest to public safety officials and responders,” DOE said.”

    –> from http://blogs.knoxnews.com/munger/2011/03/doe-releases-rad-data-from-jap.html

  117. I must amend that statement of mine, since alpha particles only travel a few centimeters in air, they could be measuring neutrons and not be close enough to measure alphas.

    Alpha decay also releases gamma rays (for some decay products they may be slightly delayed though), which are measured, but with simple GM gamma counters you have no way of telling which decay mode it came from. You need a properly calibrated proportional gas counter and some IC logic to do that with any reasonable accuracy (uranium decay gamma energy in the 6 MeV range and plutonium 5 MeV range). The other choice is measuring the alpha particles directly, but this requires spesifically designed thin receiver elements and very close measuring distances from the source material.

    Red_Blue, I think the present MP-4 readings you are looking at might be from the other nuclear plant, Daini.

    You are correct, I totally missed that, the header clearly reads “Fukushima Dai-ini nuclear power station radiation monitoring results”. Sorry. I hate it when they build two plants and then name them with numbers. Usually you give numbers to the reactor units, not to entire power plants built 10 km apart. My appologies.

    I’ve seen some people attempt to avoid the confusion by talking about Fukushima I-1 for example (plant one, reactor one).

  118. re post by Barry Brook, on 23 March 2011 at 12:24 PM

    Barry posted an update, and in it they mentioned that they had attached a camera to the end of the arm on the concrete pumper and they would assess some pool aspects once they finished water injection and retrieved the camera….

    I’ve been meaning to ask ever since then, why in the world didn’t they rig co-ax from the camera into the truck cab so they could see things in real time and not have to wait to play back after the fact?

    For that matter, does anyone know if the radiation levels high enough to disrupt a small remote control craft? If not, why in the world haven’t they used something like a hobbiest’s remote control helicopter, or one of the newer small surveillance aircrafts such as: http://www.youtube.com/watch?v=9eA1XY__AdQ&feature=player_embedded

    (if you think that’s kewl and could be useful, check out the hummingbird camera: http://www.physorg.com/news/2011-02-robot-hummingbird-flight-video.html that puppy could be flow thru some awfully small spots and still be able to literally get a birds eye view of the condition of various areas)

    It seems something like these would have been ideal early to assess the SFPs’ condition, along with any other part of the facility they could manage to fly the thing into. Heck, attach a long string with a small weight at the bottom, and a lightweight thermometer, and they could have not only seen the area up as close as desired, but also hovered over the non-existent roof and lowered down so the string went in the pool to measure the depth, and the thermometer pick up the temps…. or even perhaps other instrumention if lightweight enough that the aircraft could support it. Something like this would have at least been worth a try I would think — worst case, you lose the aircraft.

    Obviously I have no clue what sort of dose rates start significantly interfering with radio signals, however – and this seems like such a simple idea that I suppose the most likely answer is that it’s not possible under the conditions… but then you never know what gets overlooked or not thought of in emergency times either…

  119. @David Kahana: what you write is correct, regarding the construction
    of a large clean water reservoir, but I wonder how it would be
    possible to keep it intact from a 10 meter wave and, even so, how use
    it with the pumps out of order.

    @Bergonella

    You are of course absolutely right, destruction of any such reservoir
    by a 14m (!!) tsunami wave, such as was experienced in this case,
    would be a major concern, and of course even larger waves are
    possible. The whole structure and all the necessary piping would have
    to be earthquake hardened and protected to whatever degree possible
    against tsunami. My idea was: place the reservoir well above the
    reactor vessel, say 10m-20m, so that sufficient hydrostatic pressure
    for low pressure water injection into the core would exist even in a
    station blackout, thus no need for mobile power generators for as long
    as the extra cooling water lasts.

    I agree that the plant response has been good, given the severity of
    the event. The operators were dealt a very bad hand.

    As to the idea of an uphill gravity fed storage pond – keep in mind
    that you’d have to be able to site one safely, both in terms of any
    reasonable volume, but also such that it wouldn’t be a flood risk for
    the power station below in case of, ya, earthquake, or dam break, or
    terrorist attack, etc. Then as others have mentioned I believe,
    whatever caused a loss of both off site power and diesel generator
    power is awfully likely to rupture any supply pipes that you’d have
    going from the pond down into the plant…

    I suspect this is one of those ideas that sounds good, but just
    doesn’t cut it from a number of standpoints once the
    engineering/design begins to be seriously considered.

    @RationalDebate:

    All good points and they are well taken. However, I did a little
    research and found that in some ABWR designs that have been proposed,
    passive, gravity driven core cooling systems are in fact
    incorporated. Extra coolant water is placed into large pools inside
    the primary containment and above the level of the core. The primary
    containment structure is also far larger and more robust than the Mark
    I on these pretty old GE/Hitachi units.

    Variations of a passive safety containment for a BWR
    with active and passive safety systems

    However this is a design proposal, and I don’t know to what extent
    such modifications have been implemented in the newer reactors in
    Japan’s fleet.

  120. i-Robot is missing some great PR here.

    http://www.irobot.com/gi/ground/

    They should be air-freighting in a couple dozen of these.
    Plenty of RC helos control without radio. They use pulsed IR. I’m amazed at the sensitivity of my home theater receiver to it’s remote control. Point the remote at the opposite wall and runs the receiver.

  121. A number of posters have pointed out that radiolysis of water by radiation from fuel rod assembly also generates H2. This H2 generation mechanism is in addition to any H2 produced from zirconium cladding oxidation by steam. (fuelfiz 22 Mar 11:32 AM, CyrilR 22 Mar 8:16 PM, Barry Brook 23 Mar 6:30 PM).

    In Reactors 1-3, venting of steam containing H2 from the RPV to the primary containment on to the reactor building interior is a possible source of H2 for explosions in Reactor building 1 & 3. In these building, H2 generated from fuel assemblies in the SFP could also contribute some H2.

    The 548 fuel assemblies in Reactor 4 were removed on Nov 30 2010 and put into the R4 SFP along with 783 older fuel assemblies. Since there were no fuel assemblies in reactor 4, the H2 for the March 15 6:00AM building 4 explosion must have come from the SFP (or have been ducted into building 4 from Reactor 3, which I believe is highly unlikely).

    To understand H2 explosions in R3 and R4 buildings, there are several sources of information:

    1) “Light Water Reactor Hydrogen Manual” NUREG/CR-2726, which is a very complete discussion of how H2 can be generated including Zr oxidation by steam and also by radiolysis (among others). See http://www.nrc.gov/reading-rm/doc-collections/nuregs/contract/cr2726/

    2) BWR Mark 1 building dimensions from “Boiling Water Reactor Power Plants Sept 2007” http://www.ansn-jp.org/jneslibrary/npp2.pdf

    3) My post on fuel assemblies and Zr oxidation reactions BNC Leo Hansen 22 Mar 8:32 AM.

    The first question is about how much H2 is needed for reactor building explosion. Assuming the explosion takes in the open top space of the reactor building between the reactor fueling floor and SFP and the roof. I estimate this space as 48m by 48m by 15m high or 34,600 m3. At 60F this air space has about 1460 kg-mols of air.

    H2 has flammability limits of 4 to 75% by volume. From what I can read, truly explosive mixtures are in 6-10% range, with some quoting 18%.This whole volume doesn’t need to be filled with H2, as only maybe 1/3rd of the volume could be explosive and be detonated by a static spark.

    Lets assume the whole volume 34,600 m3 is at 10% H2: 146 kg-mols H2 or 290 kg H2. If this was at 4% H2, that’s about 120 kg H2. So we need probably somewhere in the range of 100-300 kg of H2 for a really big explosion.

    In my 22 Mar 8:32AM post, steam oxidation of 1 kg Zr makes 0.044 kg H2. A fuel assembly contains about 40 kg Zr. So for 100-300 kg H2, that’s 2270 to 6820 kg Zr or 57 to 170 total assemblies 100% oxidized. There were 548 “new” spent assemblies added to the pool on Nov 30 2010 added to the 783 already there. It does seem possible that the Zr cladding could (under the right circumstances of low level boiling water and extremely hot exposed fuel assemblies) could generate enough H2.

    Now lets look at H2 generation by radiolysis. In the “Light Water Reactor Hydrogen Manual” Chapter 2.1.4 Radiolysis of water we find Table 2-1.

    CONSERVATIVE CALCULATION OF RADIOLYSIS YIELD AND
    RATE FOR A 3300 MW(t) REACTOR WITH G(H2 )’f = 1.0
    Time after Integrated Radiolysis Yield and Rate with
    Shutdown Decay Energy G(H2 )’f = 1.0 for a 3300 MW Reactor

    Seconds cumulative kg H2
    10E2 4
    10E3 17
    10E4 110
    10E5 548
    10E6 2400

    If we scale this H2 production by radiolysis for R2 to 4 of ~2380 MW(t), we can derive the following equation for cumulative H2 production since reactor shutdown.
    At time 10E(t) seconds after shutdown, cumulative H2 production is ~ 10E(0.5x(t-1))

    For reactor 4, assuming a shutdown on Nov 25 with fuel assemblies transferred to the SFP on Nov 30, then on the Mar 11 earthquake there have been 107 days or 9.24 x10^6 secs or t=6.96. Cumulative H2 production from the 548 new assemblies was 955 kg. Note that all this H2 would have been swept away by the building ventilation by Mar 11.

    For reactor 4, on Mar 15, the day of the R4 building explosion, there were 112 days or 9.68×10^6 secs or t= 6.99. Cumulative H2 production was 984 kg. This is just 984-955 = 29 kg of H2 produced by radolysis from March 11 to March 15.

    I conclude that H2 production by radiolysis from R4 SFP did occur and contributed H2 to the open volume, but was far too small to have caused the R4 building explosion of March 15.

    Note that Table 2-1 is using a very conservative Gxf of 1.0, while Barry Brook post used a Gxf of 0.5 x 0.1 = 0.05, or 20 times less. His post indicates that at 278 hours (10E6 secs) the cumulative H2 production was 927 m3 or 82 kg compared to Table 2-1 of 1600 kg (when scaled down from 3300 MWt to 2200 MWt, a factor of ~20 less as would be expected from the different Gxf used.

  122. Pingback: Top Posts — WordPress.com

  123. Mea Culpa! I should have checked my equation against the table values before publishing. My equation has a mistake in it! The equation should be:

    At time 10E(t) seconds after shutdown, cumulative H2 production is 0.72x 10E(0.70x(t-1.2))

    NOT At time 10E(t) seconds after shutdown, cumulative H2 production is ~ 10E(0.5x(t-1))

    The 0.5 came from 0.72 x 0.70 . The 0.72 should not have been in the exponent.

    At 107 days, cumulative H2 production with the revised equation is 7750 kg. At 112 days the cum H2 production with the revised equation is 8135 kg. So the 5 day production of H2 was 8135-7750 = 385 kg.

    If the conservative Gxf = 1 is used, then radiolysis might have generated enough H2. If Barry Brook’s value of Gxf = 0.5×0.1 =0.05 is used, then h2 production would have been 385×0.05 = 19 kg and radiolysis would not be a factor.

    I’m afraid that I’ve left this clear as mud (which is about where the whole situation is now).

  124. David Kahana, on 24 March 2011 at 10:00 AM

    First, I can’t get over the tsunami size either!! I’m sure you’ve watched some of the video of that monster coming into different harbors/towns….. its essentially unimaginable, and the destruction left behind, those killed and still missing!!! It puts all the media circus over these reactors to shame for not focusing more where things are so dire. What is even more staggering is finding out that there have been bigger tsunamis… and even megatsunamis (100+ or even 200+ METERS???!!!) We even had one with Mt. Saint Helens volcano eruption in a lake right near it.

    Anyhow, on the reservoir & reactor design thing – David, my apologies – we got into discussing Fukushima design & possible gravity fed water reserves, and it just didn’t occur to me that you might not be aware of more current designs. I was just focusing on what actually happened, and your suggestions of how designers from back then might have done things differently.

    The units we’ve been discussing are called Generation II reactors, and the Fukushima Dai-ichi ones are one of the very earliest, Mark 1’s.

    Most plants operating out there now around the world are more current, considered to be significantly safer, especially since most have a large containment building rather than the Mark I containment vessel – although they’re still Gen. IIs.

    There are still a number similar to Fukushima out there operating tho. The design basis was for a 40 yr. lifespan, and many (most?) with intensive inspections for any possibly problematic issues, are passing and getting 10 to 20 year license extensions. I think that says a lot right there about the quality of design all things considered.

    There are also some Gen IIIs already built and operating – including a few in Japan. So there are at least a few Gen III designs that have been licensed (which is a nation by nation affair), and that have already been built and are operating. Other Gen III designs are close to being licensed or in various stages of the process.

    Gen IIIs are also often referred to as “inherently safe” or “advanced” reactors (although the latter moniker seems to be more and more reserved for the Gen IV’s – which are for the most part still theoretical and/or design stage, not yet prime time) – or as you already discovered, ‘passive’ reactors or similar terms. Anyhow, Gen III’s are thought to be far safer than the already proven safe Gen II’s, by typically at least an order of magnitude. In no small part because they have emergency cooling designs that don’t require intervention, pumps, diesel generators, and so on. While this varies from design to design, for the most part they also have few parts/valves, less overall piping — less complexity, so less that could fail or cause problems.

    There are also a number of ‘small’ and/or ‘mini’ and ‘micro’ reactor designs out there now too. I think most, maybe all of those, are still not quite to the commercial stage yet although they are close. There may be a very few that have working plants out there, I just don’t recall offhand.

    Anyhow, you may have a lot of fun looking into some of these. They’re pretty intriguing.

    Regardless, our cooling water makeup discussion was for the most part already to some extent outdated, or specific to the already built and long operating facilities that have similar design to these quite old Fukushima reactors, and maybe from the standpoint of whether it will turn out that any retrofits along these lines would be useful for them. But the newer Gen IIIs at least are already far ahead of the game in this regard at least as best I know.

    Here are a few links along these lines:

    General BWR Systems Overview (Gen II mainly, if I recall correctly) http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

    I don’t know just how they’d classify EBR-II – it’s been around for ages, I actually toured in many years ago and was tempted by their offer
    to come work or do post doc there. Would have been rolling in data they already had, could have written papers out the wazoo, intriguing as all heck, but it’s very cold up there in Idaho & in the middle of nowhere! They actually TRIED to get it to overheat a couple of times, reactor said ‘no way, won’t do it.’ http://www.anl.gov/Media_Center/logos20-1/passive01.htm

    Here’s an article that gives a decent overview of the different advanced reactor design, and if I recall correctly also compares safety between Gen II’s & III’s http://www.world-nuclear.org/info/inf08.html

    And here’s one on “small” reactors: http://www.world-nuclear.org/info/inf33.html

    I’m pretty sure that same site has another page on micro’s or mini’s or whatever they’re calling the sizes that are smaller than ‘small,’ but I don’t have a link handy.

    Have fun!!

  125. Let me make one comment about the media. Have you noticed that whenever the media reports on something that is in your field or area of expertise that they always get important things wrong and many times come to the wrong conclusion? Why then listen to them for other things. They are just as wrong about those as well.

  126. Can anyone comment on whether the concerns raised in this article are valid?

    http://www.nytimes.com/2011/03/24/world/asia/24nuclear.html?_r=1&hp

    We’ve got at least 10 days to two weeks of potential drama before you can declare the accident over,” said Michael Friedlander, who worked as a nuclear plant operator for 13 years.

    Western nuclear engineers have become increasingly concerned about a separate problem that may be putting pressure on the Japanese technicians to work faster: salt buildup inside the reactors, which could cause them to heat up more and, in the worst case, cause the uranium to melt, releasing a range of radioactive material.

  127. Can someone comment (or link) the safety features of spent fuel handling for Gen III reactors?

    I understand that the spent fuel pool is not located immediately above the primary containment like the Fukushima plants, but what about cooling? Do the pools use passive cooling like their reactors?

  128. (1) Plant Status as of March 23
    – Water Spray to Spent Fuel Pool
    Unit 3: 11:00-13:20, 35 ton using Fire Truck, Water spray by Hyper Rescue Squad was cancelled due to the smoke from unit 3 reactor building.
    Unit 4: 10:00-13:02, 130 ton using Concrete Pump
    – Power Supply
    Unit 1: Receiving power from unit 2 bus, conducting electrical equipment inspection.
    Unit 2: Completed off-site power recovery work, conducting electrical equipment inspection.
    Unit 3: Main control room lighted (22:46, March 22)
    Unit 4: Completed off-site power recovery work, conducting electrical equipment inspection.
    Unit 5,6: Complete switching to off-site power.
    – Other
    Unit 3: Black smoke appeared from unit 3 at 16:20. Personnel tried to confirm the smoke using search light during the night, but it was difficult to confirm whether still smoke exists or not.
    Reserving water in the make-up water (MUW) tank for preparation of inject fresh water into the RPV. Though test run of the MUW pump was planned in the evening of March 23, it was postponed due to the smoke.
    Unit 5: RHR seawater tripped at 17:20. This happened when operator switched temporary pump power supply. We are planning to start a stand by unit in the morning of March 24. From the trend of the reactor water temperature, we believe that we can keep Unit 5 in cold shutdown for the time being.

    (2) Result of Atmospheric Radioactive Monitoring sampled on March 22

    On March 23, we conducted nuclide analysis of radioactive materials contained in the air which were collected on March 22 at Fukushima Daiichi Nuclear Power Station. Radioactive materials were detected again as shown in the attachment. We reported the result to NISA (Nuclear and Industry Safety Agency) as well as to Fukushima Prefecture.

    (3) Integrity assessment of RPV and PCV at measured temperature Temperature at unit 1 RPV and PCV were higher than design temperature for these. But we assume the RPV and PCV could maintain structural integrity under the current condition.
    – RPV: Nozzle and Bottom temperature were slightly higher than the design temperature of 302C. Considering internal pressure of RPV and hydraulic head pressure (20m), stress is estimated to be 5 MPa. The yield stress of RPV at 400C is 466 MPa and this is greater than 5MPa.
    – PCV: D/W temperature was 390-400 C, greater than PCV design temperature, 139 C. Considering D/W internal pressure 0.3MPa and deadweight, stress intensity is estimated to be 67MPa for D/W and 74 MPa for S/C. Since extrapolated yield stress is 150 MPa, we assume structural integrity of the PCV is maintained under the current stress of 67 and 74 MPa.

  129. “Steam rising from 4 reactors at Fukushima plant
    An NHK helicopter crew has confirmed what appears to be steam rising from No. 1, 2, 3 and 4 reactor buildings at the troubled Fukushima Daiichi nuclear power plant.
    This is the first time that steam has been seen coming out of the No.1 reactor.
    The helicopter crew was filming from a location more than 30 kilometers from the plant shortly before 7:00 AM on Thursday.
    The Tokyo Electric Power Company says that black smoke seen rising from the No.3 reactor building on Wednesday was no longer visible as of 6:00 AM Thursday.”

    Thursday, March 24, 2011 09:31 +0900 (JST)
    http://www3.nhk.or.jp/nhkworld/index.html

  130. The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
    As of 10:00AM (EST), March 23, 2011
    • Radiation Levels
    o At 6:30PM (JST) on March 23, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 249 micro Sv/hour.
    o Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on March 23 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1303962.htm
    o For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
    • Fukushima Daiichi Unit 1 reactor
    o At 2:33AM on March 23, amount of seawater injection has increased by using water supply system in addition to water extinction system (from 2 cubic meter per hour to 18 cubic meter per hour).
    o At 2:00PM on March 23, pressure inside the reactor core: 0.376MPa.
    o At 2:00PM on March 23, water level inside the reactor core: 1.7 meters below the top of the fuel rods.
    o At 2:00PM on March 23, pressure inside the primary containment vessel: 0.345MPaabs.
    o As of 2:00PM on March 23, the injection of seawater into the reactor core continues.
    o As of 7:00PM on March 23, external power generation is connected through Unit 2 and the functionality of the electric devices is being checked.
    • Fukushima Daiichi Unit 2 reactor
    o At 4:07PM on March 22, TEPCO began to inject seawater into the spent fuel storage pool, until 5:01PM (approximately 18 tons in total)
    o At 4:20AM on March 23, the temperature of the spent fuel pool: 123.8 degrees Fahrenheit.
    o At 2:00PM on March 23, pressure inside the reactor core: -0.036MPa.
    o At 2:00PM on March 23, water level inside the reactor core: 1.25 meters below the top of the fuel rods.
    o At 2:00PM on March 23, pressure inside the primary containment vessel: 0.11MPaabs.
    o As of 2:00PM on March 23, the injection of seawater into the reactor core continues.
    o As of 7:00PM on March 23, approximately 58 tons of water in total has been injected into the spent fuel storage pool.
    o As of 7:00PM on March 23, external power generation is connected and the functionality of the electric devices is being checked.
    • Fukushima Daiichi Unit 3 reactor
    o At 10:46PM on March 22, lighting was restored in the Central Control Room.
    o At 9:10AM on March 23, pressure inside the reactor core: -0.104MPa.
    o At 9:10AM on March 23, water level inside the reactor core: 1.8 meters below the top of the fuel rods.
    o At 9:10AM on March 23, pressure inside the primary containment vessel: 0.1MPaabs.
    o At 11:00AM on March 23, TEPCO began to inject water into the spent fuel pool, until 1:20PM (approximately 35 tons in total).
    o At 4:20PM on March 23, black smoke was emitted from the secondary containment building. (Under investigation)
    o As of 2:00PM on March 23, the injection of seawater into the reactor core continues.
    o As of 7:00PM on March 23, approximately 3,927 tons of water in total has been shot to the spent fuel storage pool.
    • Fukushima Daiichi Unit 4 reactor
    o At 5:17PM on March 22, TEPCO began to shoot water aimed at the spent fuel pool, until 8:32PM, with a specialized vehicle normally used for pumping concrete (approximately 150 tons in total).
    o At 10:00AM on March 23, TEPCO began to shoot water aimed at the spent fuel pool, until 1:02PM, with a specialized vehicle normally used for pumping concrete (approximately 130 tons in total).
    o As of 7:00PM on March 23, approximately 535 tons of water in total has been shot to the spent fuel storage pool.
    o As of 7:00PM on March 23, external power generation is connected and the functionality of the electric devices is being checked.
    • Fukushima Daiichi Unit 5 reactor
    o At 7:41PM on March 22, it was confirmed that power supply was completely switched form diesel generator to external power.
    o At 2:00PM on March 23, the temperature of the spent fuel pool: 102.2 degrees Fahrenheit.
    • Fukushima Daiichi Unit 6 reactor
    o At 7:41PM on March 22, it was confirmed that power supply was completely switched form diesel generator to external power.
    o At 2:00PM on March 23, the temperature of the spent fuel pool: 67.1 degrees Fahrenheit.

  131. Ken F, on 24 March 2011 at 12:00 PM said:

    Can anyone comment on whether the concerns raised in this article are valid?

    Some of their concerns have been mentioned here. This is going to be a big mess to clean up. The article seems to be fairly balanced. They are emphasizing the negative, but those concerns have to be dealt with. I think they are going to have to flush a lot more of this out into the ocean. People are not going to like that, but I can see no other way to deal with the large volumes of radioactive water.

  132. Look at this picture of building 3, where is the SFP?

    That is a stunning image….. I see nothing mechanical or identifiable.

    Researcher Gerhard Wotawa of the Vienna-based Central Institute for Meteorology and Geodynamics says that the radiation released from the Fukushima power plant has been about the same as the radiation released in Ukraine’s Chernobyl nuclear accident in 1986 – but with an important difference.

    “Chernobyl did not lie close to the Pacific Ocean and the wind did not go into the ocean in that direction,” said Wotawa.

    That, Wotowa says, has limited the harmful effects of the radiation leaks. He also notes that there has not been a major explosion at the Fukushima power plant. But he warns that high levels of radioactive cesium remain a concern.

    http://www.voanews.com/english/news/asia/Experts-Cite-Improvements-and-Dangers-at-Crippled-Japanese-Nuclear-Reactor-118543829.html

  133. Look at this picture of building 3, where is the SFP?

    This picture was apparently taken from north west, so the pool is then towards the opposite side of the building. It would not be visible even if the building was otherwise intact, but the closest wall to the photographer removed.

    Researcher Gerhard Wotawa of the Vienna-based Central Institute for Meteorology and Geodynamics says that the radiation released from the Fukushima power plant has been about the same as the radiation released in Ukraine’s Chernobyl nuclear accident in 1986…

    So, it appears Dr. Wotawa is revising his already exceedingly high estimates even higher. The first estimate was for 20-50 % of Cs-137 and 20% of I-131, which add up to 70% as the upper bound.

    He also doesn’t seem to be that interested in making the point (directly to the media or even in his “press release”) that a lot of other nuclides were released in the Chernobyl accident and Cs and I were only 3% of the total according to his numbers. Also, stating that it has been “about the same” would in my opinion require qualifications that he means the activity, not equivalent doses or anything comparable to health effects or the need for protection measures.

  134. Can anyone comment on whether the concerns raised in this article are valid?

    They have basically been bleeding off steam from the reactor pressure vessel to the torus for the last 12 days (if safety systems are operating correctly), so there is a great deal of radioactive water in the suppression pool. Radiation levels in the turbine room of reactor 2 are reported at 500 millisieverts. You can’t do much in that environment with radiation levels so high.

    http://english.kyodonews.jp/news/2011/03/80532.html

  135. Pingback: Where’s the nuclear Armageddon we were promised? « politichix

  136. > an air sampling and rain water sampling station
    That’s good info

    From the above Kyodonews link:

    “While the maximum vessel temperature set by the reactors’ designers is 302 C degrees, the surface temperature of the No. 1 reactor vessel briefly topped 400 C and dropped to about 350 C by noon, and that of the No. 3 reactor vessel stood at about 305 C, the agency said….TEPCO increased the amount of seawater injected into the No. 1 reactor by nine times to help cool it down.”


    More detail here than I’ve seen elsewhere on the valves and plumbing generally:
    http://www.ansn-jp.org/jneslibrary/BWR_Safety_Design.pdf

    hat tip to: http://www.hubberts-arms.org/index.php?PHPSESSID=c93e43e73924452b6adcb9a4c154e1ea&topic=5303.msg51167#msg51167

  137. New Problems Arise…….

    Richard T. Lahey Jr., who was General Electric’s chief of safety research for boiling-water reactors when the company installed them at the Fukushima Daiichi plant, said that as seawater was pumped into the reactors and boiled away, it left more and more salt behind.

    He estimates that 57,000 pounds of salt have accumulated in Reactor No. 1 and 99,000 pounds apiece in Reactors No. 2 and 3, which are larger.

    The big question is how much of that salt is still mixed with water and how much now forms a crust on the uranium fuel rods.

    Crusts insulate the rods from the water and allow them to heat up. If the crusts are thick enough, they can block water from circulating between the fuel rods. As the rods heat up, their zirconium cladding can rupture, which releases gaseous radioactive iodine inside, and may even cause the uranium to melt and release much more radioactive material.

    http://www.nytimes.com/2011/03/24/world/asia/24nuclear.html?partner=rss&emc=rss

  138. DIscussion here well worth reading; it’s a General Electric blog I stumbled on via Google just now:

    http://www.gereports.com/the-mark-i-containment-system-in-bwr-reactors/

    On the page see also in the sidebar:
    How it Works: White Paper on Mark I Containment A new report has just been developed on the Mark I containment design that is in use at the Fukushima Daiichi nuclear power plant….

    Mark I Containment Facts & The New York Times We’d like to set the record straight concerning misleading comparisons between GE’s boiling water reactor (BWR) design and that of a pressurized water reactor (PWR). ….

    Setting the Record Straight on Mark I Containment History We address several incorrect claims made about the Mark I containment system design at the Fukushima Daiichi Power Plant. ….

  139. Please explain what this means?
    Does it indicate re-criticality?

    Neutron beam observed 13 times
    Kyodo News

    Tokyo Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of its crippled Fukushima No. 1 nuclear plant.

    Tepco said the neutron beam measured about 1.5 km southwest of the plant’s Nos. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour. This is not a dangerous level of radiation, it added.

    The utility said it will also measure uranium and plutonium, which could emit a neutron beam.

    In the 1999 criticality accident at a nuclear fuel processing plant run by JCO Co. in Tokai, Ibaraki Prefecture, uranium broke apart continually in nuclear fission, causing a massive amount of neutron beams.

    In the latest case at the Fukushima No. 1 plant, a criticality accident has yet to happen.

    But the measured neutron beam may be evidence that uranium and plutonium leaked from the plant’s nuclear reactors and spent nuclear fuel have discharged a small amount of neutron beams via fission.

    http://search.japantimes.co.jp/cgi-bin/nn20110324a6.html

  140. Barry, thanks for the updates!

    Ok, how are we getting negative pressure in the RPV’s, with the top 1/2 to 1/3rd still uncovered?

    I wonder why they didn’t bring in more than one of the concrete trucks – and why they have the one pumping to unit 4 SFP, if unit 3 (reactor and/or SFP) is the greater concern?

    Also, at some point the updates or reports had an estimated fuel damage percentage for I think at least 2 of the reactors… I would have thought that they’d have run calc’s based on the rad mix being seen and been able to estimate damage – so I’m wondering why they’ve stopped including those figures (maybe because who could tell how much damage came from which core and/or pool?)

    Are there some smaller steam vents open on the system, or should there only be venting when they’ve done the major pressure releases?

  141. Shelby: a quick search reveals that seawater is ~3.5% salt, by weight, and saturation at 100ºC is about 39%. So you’d need about 90% of the injected seawater to boil off before you hit saturation & started getting serious precipitation problems (although the local concentration around the fuel rods, where boiling is occurring, may be high enough to cause some precipitation).
    That’s not considering the volume of water that was already in the reactor, though.

    Does anyone know the quantities of seawater injected? Is it a significant amount, compared to the amount of water the reactor normally holds?

    The report posted by Barry above mentions figures of 2m3 per hour, increasing to 18m3/hr as they bring other cooling pumps online.

    I imagine that as soon as they get the chance, they’ll start flushing the reactor with fresh water to reduce any salt build-up, but then they’ll have to find somewhere to store what is now probably radioactive saltwater…

  142. Bern

    It would seem to me that Richard T. Lahey Jr., who was General Electric’s chief of safety research for boiling-water reactors when the company installed them at the Fukushima Daiichi plant, would have made his best accurate calculations before being interviewed by the NY Times?

    [deleted comment on the motives of a person. Violates BNC comment policy]

  143. Nuclear Safety Commission has produced this map predicting the thyroid dose for a hypothetical person staying outside day and nite near the plant since March 12th to March 24th based on the SPEEDI network of radiation sensors (and most likely also data from mobile sensors also). The dose lines starting from red close to the plant and extending to yellow about 10 km south east of Fukushima City (line number 5) read as follows:
    1: 10,000 mSv
    2: 5,000 mSv
    3: 1,000 mSv
    4: 500 mSv
    5: 100 mSv

    Since these are thyroid doses, converted to whole body doses they would be 1/20 of these numbers. NSC also estimates that protection factors in the region from staying inside range from 1/4 to 1/10 depending on building type.

    Remember that while there have not been evaquation in the 20-30 km zone even to the direction of the heaviest fallout (nort west), people from these rural areas have self evacuated to a large extent.

  144. would have thought that they’d have run calc’s based on the rad mix being seen and been able to estimate damage – so I’m wondering why they’ve stopped including those figures (maybe because who could tell how much damage came from which core and/or pool?)

    Controls against any fuel damage in normal plant operations is carried out by sampling the coolant water. This will give you pretty quickly a good idea of how many of the rods have suffered damage and also to what extent (maximum temperatures). I guess these samples were obtainable at the early phase of the crisis, but could be impossible to obtain now with the radiation levels even in the auxiliary buildings.

    I think they will start to worry about sampling various waters and pipes when they can get the cooling situation properly under control.

  145. Upthread earlier to day, I asked about these pressure and temperature readings.

    If the temperature in the RPV is 400 C then the pressure in the vessel is > 200 – 250 bar (3000 – 3800 psi) and the fluid in the vessel is super critical. It is neither liquid or vapour. Although the temp and pressure are considerably above the design of 300 C and 170 bar they have calculated that the vessel is in no danger from this over pressuring.

    Presumably they have added a lot of seawater to the RPV to get 50 – 100,000 lbs of salt accumulated in each reactor. I am sure somebody can do the math.

    What I don’t know is how the salt behaves in water in the super critical range. It might stay in solution and blow down when they release steam to the torus.

    All of my experience is on metallurgical waste heat boilers at much lower temperatures and pressure (650 psi). Could one of the ex nuke plant guys please comment on my assessment.

    Thanks

    E

  146. Does anyone know the quantities of seawater injected? Is it a significant amount, compared to the amount of water the reactor normally holds?

    Injection rates have not been published until yesterday, but TEPCO should have them. Calculations have been done based on estimated decay heat (how much water is needed to be added to account for boiling).

    With different assumptions people have come to different figures, but one calculation I did assuming 15 C seawater temperature and one of the 2,381 MWt reactors 10 days after shutdown was about 160 m^3 per day. That’s a substantial amount of water, 6.7 m^3/h It’s also between the rates they have adjusted the water flow recently (2-11 m^3/h).

  147. If the temperature in the RPV is 400 C then the pressure in the vessel is > 200 – 250 bar (3000 – 3800 psi) and the fluid in the vessel is super critical.The published pressures in the vessels are a lot less than that. See the graphic at the top. For instance, for reactor 1 the higher value is 0.328 MPa = 3.28 bar = 48 psi. Can someone explain this conflict?

  148. @Red_Blue
    That chart helps make sense of Edano’s statement yesterday. NHK quotes him (http://www3.nhk.or.jp/daily/english/23_35.html) as saying doses outside the 30km zone could be as high as 100mSv in 24 hours. This must be a misquote, but over 100mSv thyroid dose in the last week for the people 30 -40 km Northwest of the plant seems possible given that map.

    Still can’t find anything on wether the evacuation zone is the circle shown on MEXT maps, or is based on measured radiation levels. Those 30km Northwest locations like Tsushima have consistently shown levels higher than those only a few km from the NPP. Could this be because they are on top of a mountain range and the reactor vent stacks are quite tall?

  149. The design pressure of R1 PRV is 1250 psig (~300C steam). As you increase the pressure beyond that, you reach a point that the weak point on the vessel or nozzle ruptures. No way ever, not even close for 3200 psig 373C critical.

  150. DIscussion here well worth reading; it’s a General Electric blog I stumbled on via Google just now:

    http://www.gereports.com/the-mark-i-containment-system-in-bwr-reactors/

    On the page see also in the sidebar:
How it Works: White Paper on Mark I Containment A new report has just been developed on the Mark I containment design that is in use at the Fukushima Daiichi nuclear power plant….

    These are pretty interesting documents (particularly the GE white paper, and the NEI report on Mark I containment). They describe the containment system very well as I understand it. But one thing they don’t describe: how hydrogen gas made its way into the operating floor of the secondary containment building of 1 and 3 (above the primary containment vessel). They talk about wetwell and drywell boundaries, and they also talk about hardened vents, installed after the original design and construction of these reactors (and how these carry steam, residual heat, and pressure “outside the reactor building”). Maybe this has been talked about elsewhere on the site, but I think there is some speculation that a flange and rubber seal on the removable head of the primary containment vessel failed under pressure (which was at twice the design tolerance), and released hydrogen gas to the operating floor of the reactor building (which then exploded and damaged the upper floors and spent fuel pools of buildings 1 and 3). This is consistent with a “pipe break in the reactor coolant system,” which they list as a possible concern indicated by the rise of pressure in the primary containment structure of 1 and 3, but would contradict the claim of GE and NEI that “”The Mark I containment vessels appeared to have held pressure to well above the design pressure.”

    These are probably thoughts for another thread (and another time), but I thought I would put them out there if anybody is interested. This scenario is described in the following video by a Japanese engineer involved with the design of the containment structure of Reactor #4 at Fukushima Daiichi (which was shut down for inspection and repairs). He has since become an outspoken critic of the power plants at Daiichi, so you should keep that in mind if you decide to watch the video (which has simultaneous translation):

    http://www.ustream.tv/recorded/13410573

  151. Can someone explain this conflict?

    The reactor is no longer in a closed system.

    Where is the 6.7m^3/h of water going after boiling?

    Through the SRV to the pressure suppression pool (and when venting is done, through the vent lines of the pressure suppression pool or the drywell to the secondary containment ventilation ducting, or if TEPCO had installed the direct venting modification, directly to the stack bypassing the standby gas treatment system).

    Still can’t find anything on wether the evacuation zone is the circle shown on MEXT maps, or is based on measured radiation levels.

    The only official data is the geographical distance from the two plants (for evacuation).

    { The government advice about staying inside is getting more convoluted, now they’re saying things along the line of “you are fine outside of 30 km, with no health effects, but if you are still concerned and wish to reduce your exposure even further, then you can do as follows…” and then “you chould stay inside “downwind”” without specifying any distances or wind directions. There are also suggestions along the same lines for not going outside during rain (even while at the same time stating that there is no health risk whatsoever, if you go outside during rain, just that if you are concerned, then don’t go outside during rain!).
    I’m not so sure this will be successful as a communication strategy in the long run. But explaining why this makes (at least some) sense to the Japanese would be a long story about national identity. Basically, while the government concedes that it is unable to allay the radiation fears of the population, it still tries to be helpful and giving out instructions that will make people feel better, even if it will not actually help them in any practical scientifically supportable way.} PLEASE SUPPLY REFERENCES/LINKS TO THIS COMMENT.

    I hope that explanation helps.

    MODERATOR
    TO GIVE THE COMMENTERS SOME IDEA OF WHAT WE ARE MODERATING,THE STATEMENT {IN BRACKETS}IN THIS COMMENT IS THE KIND OF UNSUPPORTED HEARSAY AND PERSONAL OPINION WE WOULD NORMALLY DELETE AS IT IS NOT BACKED UP BY ANY REFERENCES/LINKS. WE ARE NOT DELETING OPINION/APPRAISAL ON WORKS/REFERENCES THAT HAVE BEEN GIVEN ATTRIBUTION.

  152. This is good news. Very short-lived reading. BTW 210 becquerels doesn’t sound very much to me. Can anyone on the blogcomment on that? Also is the safe level reasonable or overly cautious.Though I suppose it is better to err on the side of caution.

    “After widespread alarm a day earlier when radioactive iodine above the safe level for infants was discovered in the capital’s tap water, officials said it had dropped back to non-dangerous levels.

    In one Tokyo ward, Katsushika, a water sample that was taken on Tuesday and publicized on Wednesday had contained more than double the legal limit for infants, at 210 becquerels per kilogram.

    But the level fell back to 79 in a test Thursday, a Tokyo official told AFP. The upper limits are 100 becquerels for infants and 300 for older people.”

    http://www.dailytelegraph.com.au/news/breaking-news/light-back-on-at-fukushima-reactor-as-radiation-in-tokyo-water-subsides/story-e6freuz9-1226027563385

  153. Oh – I see the level is per kilogram(of bodyweight?)

    No, it’s per kilogram of water, which is one liter. Radionuclide contamination by activity is given per volume or weight and due to foodstuffs being usually weighted, it’s given in kg. Since most consumable liquids are water by majority of concentration, these figures are often converted back to volumes.

    100 Bq if I-131 in kg of water is a very low level of activity, but in line with IAEA/FAO/WHO recommendations. Some countries have higher limits than that (like 500 Bq for example), but as has been discussed before, these values are based on extremely conservative calculations designed avoid dose increases less than natural (or “normal”) doses in completely hypothetical scenarios where someone would drink water with that level of contanimation as their only fluid intake for a year. For iodine, that would essentially require a new nuclear plant disaster every month due to the short half life of the key iodine isotopes.

  154. IN THIS COMMENT IS THE KIND OF UNSUPPORTED HEARSAY AND PERSONAL OPINION WE WOULD NORMALLY DELETE AS IT IS NOT BACKED UP BY ANY REFERENCES/LINKS.

    Edano’s statements to the effect (that concerned people downwind should stay inside) were already sourced in English by NHK and Kyodo News.

    The suggestion not to go outside during rain, even when there is no danger, comes from PM Kan’s office.
    MODERATOR
    Thank you for the links – that is all we ask for to avoid moderation of this category of comments.

  155. [deleted for personal attribution of person's motives]
    “no risk to human health” and

    “These are precautionary measures. Even if you don’t take these measures, it doesn’t impose any threat on your health”

    Please give us the complete report not your edited version of it.

    QUOTE
    “To people living in Tohoku and Kanto regions — There is no risk to human health, even if it rains. Please rest assured.

    Higher-than-normal levels of radiation could be detected in rain, but it would contain only a small amount of radioactive substances which do not affect health at all. The levels wouldn’t go beyond the average of natural radiation dose. If you are concerned, please follow these instructions.

    1. Wait inside until the rain stops unless it is an emergency.
    2. Make sure of covering up hair and skin as much as possible
    3. There is no problem even if your clothes or skin is exposed to rain. If you are still concerned, wash it carefully with running water.

    These are precautionery measures. Even if you don’t take these measures, It doesn’t impose any threat on your health”
    http://www.kantei.go.jp/foreign/incident/index.html.

  156. Two developments regarding spent fuel pools:

    A temperature reading for unit 4 fuel pool was shown on official statistics. Temperature was shown as 100 degrees C (!) at 02:40 JST 24th. However a subsequent release of data for 11:00 JST shows ‘Incorrect Indication’ instead of a temperature.

    Water injection into unit 3 fuel pool is now said to be done via the ‘cooling and purification line’, both on March 23rd and March 24th.

    http://www.nisa.meti.go.jp/english/files/en20110324-2-1.pdf

    Previous report that showed 100C temp for unit 4 spent fuel pool:

    http://www.nisa.meti.go.jp/english/files/en20110324-1-1.pdf

  157. I wonder why the japanese authorities should release data and brief worldwide about an incident which is – for the moment being, and for most of its evolutions – limited to a very local scenario.
    sorry for uttering an opinion, but I can assume that even as a mere opinion it could be well supported by history and data we collected up to now.
    such a behaviour can be annoying, but I cannot see anything suspicious or malicious about it.

  158. Does this indicate there has been some fission occurring outside the containment vessel? The press has really shied away from this report (you have to dig to find it in a handful of sources) and no one here seems to want to address the question either. What could cause 13 neutron beams to be observed from 1.2km away?

    Neutron beam observed 13 times
    Kyodo News

    Tokyo Electric Power Co. said Wednesday it has observed a neutron beam, a kind of radioactive ray, 13 times on the premises of its crippled Fukushima No. 1 nuclear plant.

    Tepco said the neutron beam measured about 1.5 km southwest of the plant’s Nos. 1 and 2 reactors over three days from March 13 and is equivalent to 0.01 to 0.02 microsieverts per hour. This is not a dangerous level of radiation, it added.

    The utility said it will also measure uranium and plutonium, which could emit a neutron beam.

    In the 1999 criticality accident at a nuclear fuel processing plant run by JCO Co. in Tokai, Ibaraki Prefecture, uranium broke apart continually in nuclear fission, causing a massive amount of neutron beams.

    In the latest case at the Fukushima No. 1 plant, a criticality accident has yet to happen.

    But the measured neutron beam may be evidence that uranium and plutonium leaked from the plant’s nuclear reactors and spent nuclear fuel have discharged a small amount of neutron beams via fission.

    http://search.japantimes.co.jp/cgi-bin/nn20110324a6.html

  159. BerGonella, on 24 March 2011 at 9:34 PM said:

    I wonder why the japanese authorities should release data and brief worldwide

    Well, I think you would agree they have an obligation to release data and information to their own people, and the world would get it as a by-product. Also, they have obligation to deliver timely information on there types of nuclear events to the IAEA. I don’t know what point you are trying to make. Information should be hidden?

  160. @Red_Blue 24 Mar 4:52PM

    Where is the 6.7m^3/h of water going after boiling?

    Through the SRV to the pressure suppression pool (and when venting is done, through the vent lines of the pressure suppression pool or the drywell to the secondary containment ventilation ducting, or if TEPCO had installed the direct venting modification, directly to the stack bypassing the standby gas treatment system).

    Thank you for answering so clearly. I’m now marginally better informed than I was a week ago
    .
    If I may impose further;
    Is it likely that the secondary containment ventilation survived the hydrogen explosions which destroyed much of the secondary containment?
    Is the vaporized water re-condensing in the ventilation system or stack and that is why we’re not seeing clouds of vapor?
    Has the suppression pool lost it’s ability to condense the reactor vessel steam. Has it heated to near pressure vessel temperature?
    Would this gaseous water get scrubbed of radionuclides in the suppression pool? Are there still active noble gasses in this material?

    These answers may be obvious to one better informed. To me, not so much so.
    Thank you

  161. @William Falhorn,

    Information should be hidden?

    absolutely not, sorry for my bad wording.
    it does not seems to me (though not qualified enough to be sure of it) that any essential information or data has been kept hidden or secret, at the same time I can see the lack of fine detail about the situation and its managing procedures.
    in short: this is a big trouble in a very troubled local and national scenario, and maybe it is simply not possible to present more detailed data, maybe for lack of time, maybe for lack of data itself (damaged or destroyed measuring devices in some not reachable places, perhaps)

    sorry again.

  162. Gerald, on 24 March 2011 at 7:06 PM said:

    There is a report of neutron radiation emission.

    This was discussed earlier on this thread. The levels are very low and may even be very close to the natural background produced by cosmic rays. There are some neutrons produced by the spontaneous fission of Plutonium 240, which if this is the source of the neutrons would indicate some fuel has been emitted from somewhere, reactor or spent fuel. This could be checked if a gamma spectrum was taken, as the alpha particle decay of Pu 240 is 200 million times higher that the spontaneous fission. Gamma rays are emitted during both fission and alpha decay. If they got close enough they could measure the alpha decay directly. This should be easily verified or totally disproven. I would hope they would have investigated this as fuel emission is very serious and would indicate much higher damage than suspected. I doubt this because then there would be much more of the volatile fission products emitted. Until further information this is just a puzzling report, which is already second hand.

    http://en.wikipedia.org/wiki/Spontaneous_fission

  163. All the ‘defense in depth’ backup systems to keep nuclear reactors and fuel storage pools cool seem to depend on cooling pumps driven by electric motors. Electricity to operate these pumps is to be supplied by the station’s turbines, from the grid, by diesel generators or by batteries.

    However electric supply lines, motors, control systems and generators are all easily damaged by seawater. Repairs to these components are likely to be complex and time-consuming after they have been immersed in seawater, mud and debris.

    Diesels on the other hand are not so sensitive. The engines can probably run fully submerged for some time, as long as air intakes, exhaust and fuel supplies are placed high enough to stay above water level.

    If just one backup system were to use pumps driven directly by diesel engines, by shaft, belt or chain, wouldn’t this add considerably to the overall safety?

    Frank Kandrnal made a similar point on 23 March in this thread, and suggested using steam from residual heat to drive turbines to power the pumps. However diesel engines are likely to be more robust and easier to replace, bringing in spare engine units by helicopter if necessary.

  164. @raynerpitt

    From the nature article I linked to above the steam from the reactor was used to drive the pump. This would only provide a few hours of pumping I would think. Long term they need a sourcre of power.

  165. Reports I’ve seen saying that workers have been exposed to 170 mSv of radiation seem to be incorrect. I could not see how they would know the dose to their feet as their doseometers would not be close to their feet. I found a primary document and the rate their feet was subjected to is known. Actually dosage would be dependant on how long they stayed in the water, minus any protection factor of their boots. Or they may have taken that into account when they calculated the dose rate. They were exposed to a dose rate of 170mSv/hr
    to 180mSv/hr. Some got on the skin of their feet, maybe when they were taking off their boots. Can’t tell from this information what their actual absorbtion was, but there may be radiation burns on there feet, so that is serious.

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300968438P.pdf

  166. @William Fairholm:
    With the deference due from a non-engineer, isn’t the pumping stopping if you are using steam from the reactor a self-correcting problem?
    If the reactor cools down enough so that the steam stops, well and good.
    If it starts heating up to much, then the steam should resume and so should the cooling.
    No doubt I am missing something!

  167. @David Martin:

    I am not an engineer, but at some point I would think the head of steam would not be enough to efficiently run the pumps. I do not know the details, so cannot comment directly, but they obviously needed power from somewhere else at some point, so I will leave it at just that.

  168. @Hank Roberts:
    Did you actually look at the results you get form your suggested search terms?
    I am aware that there may well have been something on the subject in the vast mass of information on the accident posted here, and many thanks for the first link your search terms throw up narrowing that down to 677 comments.
    That is of somewhat limited utility however.
    If you want to know why I suggest you look in the Library of Congress.

  169. Re: Ms. Perps and Red_Blue, discussion of I-131 in Tokyo water supply (comments of 24 March 2011 at 4:53 PM ff) —

    I tried doing some arithmetic to convert 200 Bq/litre of I-131 into lifetime cancer risk. For I-131, the concern is about thyroid cancer.

    The calculations (with links to sources) are in this comment on the latest Open Thread.

    Conclusion (tentative): The lifetime risk of thyroid cancer for a Tokyo infant might be 0.90%. A month’s ingestion of water containing this level of I-131 might elevate that risk to 1.04%:

  170. Why does the IAEA update table not include reactor temps? There is not even a field that says N/A if the temp readings are for some reason not available. Also the pressure readings are just listed in vague terms like stable or rising. That could mean almost anything. Just seems like they are not getting nor providing real data about the reactor temps or pressures.

    http://www.slideshare.net/iaea/table-summary-of-reactor-unit-status-at-of-24-march0600-utc

  171. David, the steam pumps work while there’s a cold pool of water in the torus — steam pushes hot water out of the reactor, that bubbles down into the torus and condenses; water circulates from there back up into the reactor. When the torus heats up to boiling, the pump doesn’t work. I skimmed the results, these may help (it’s got a description of how it works)
    http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/193.html

    “Figure 3.193-2
    ASSESSMENT

    Pressure Suppression Design: The pressure suppression chamber, or torus, in a BWR Mark I containment, is a steel pressure vessel in the shape of a torus below and encircling the primary containment drywell, which contains the reactor vessel and recirculation system pumps and piping (Figure 3.193-1). In the event of a LOCA, steam released into the drywell airspace is forced through (typically) eight large vent pipes to the suppression chamber. The vent pipes exhaust into a large ring-shaped continuous vent header within the torus. The header is connected to a set of downcomer pipes, which extend into the suppression pool water, and end about four feet below the water surface (Figure 3.193-2). The steam is condensed in the suppression pool water, greatly limiting the peak containment pressure.”

    (that works until the water in the suppression pool boils, then it doesn’t work any longer)

    and generally:
    http://bravenewclimate.com/2011/03/14/fukushima-more-technical-info/

    that thread gives you more search terms like “jet pump” that lead to more info when added to the first search

  172. William Fairholm, on 25 March 2011 at 12:48 AM said:

    Earlier Gerald linked to a Nature article that gave an explaination of the initial events that lead to the problems at the reactors. It mentioned that early on Unit 1 cooling system had sprung a leak. I had not seen this before. Does anyone have a direct reference for this information.

    http://www.nature.com/news/2011/110322/full/471417a.html

    Elevated pressure readings inside the primary containment structure has to come from somewhere?

    http://www.world-nuclear-news.org/RS_Massive_earthquake_hits_Japan_1103111.html

    Reactor #1: “an increase in reactor containment pressure was noted around 6pm, and “assumed to be caused by leakage of reactor coolant in the reactor containment”

  173. re post by: William Fairholm, on 25 March 2011 at 1:27 AM said:

    William, it sounds as if they knew these folks were working in pooled contaminated water – I can’t speak for Japanese protocols, but I can tell you that in the US in that sort of situation, there would be dosimetry inside the boots on these workers. Similarly, if workers will be handing something that might cause high level extremity exposure to the hands, then they’ll have dosimetry inside the gloves. Or if some situation warrants it, on top of the head even.

    Also – even in accident situations, if the dosimeter available is on the chest, but the exposure is to the feet, then you can calculate an estimated exposure to the extremities based on the dosimeter reading.

    Consider also that the primary risk from high levels of radiation exposure are to the internal organs and bone marrow. The faster the organ’s cells are dividing, the more likely they are to be damaged – that is why the first serious damage from very high doses is to the GI tract mucosal lining. The slower the tissue divides, the less harm is done.

    You can get very high doses to the extremities, relative to the trunk of the body, without any real harm. If there are burns on their feet, I would think it is entirely possible to be thermal rather than radiation burns.

    Folks here might find it interesting to know that the original ‘dose limit’ (this long before nuclear power, for researchers) was the erethemya dose. That was the point at which a researchers skin started turning red (usually the hand or hands). Then you were to stop working until the red went away, and back to it you went.

    According to the history article I’ve linked to below, they calibrated x-ray tubes by putting a hand in front of it and seeing how long an exposure was needed to turn the skin red (about 600 R). The dose needed to cause third degree burns starts at about 2000 R. In other words, very roughly speaking, 6 Sieverts or 6000 mSi, and 20 Si or 20,000 mSi.

    http://www.google.com/url?sa=t&source=web&cd=3&ved=0CCEQFjAC&url=http%3A%2F%2Flibrary.lanl.gov%2Fcgi-bin%2Fgetfile%3F23-04.pdf&rct=j&q=history%20(radiation%20or%20radiological)%20%22erethema%20dose%22&ei=162LTfybO4HItwe8tO3xDQ&usg=AFQjCNG0b_XgxTINT3XBjDy9WS20_hekmQ&cad=rja

  174. Thanks, EL. I wasn’t reading their reports that early. I may even have read it somewhere, but in the mass of information, it didn’t click. Seeing it on a timeline makes it easier to understand what was going on.

  175. Regarding recent oficial updates about the common spent fuel pool. Pool was around 57 degrees C at 13:15 on March 23rd. Power became available at that location today, and cooling was started at 18:05 March 24th. Temperature of pool water at 18:40 on 24th said to be 73 degrees C! Hope the cooling works, any ideas as to why the temperature is so high now compared to recent days?

    Source of info is http://www.nisa.meti.go.jp/english/files/en20110325-1-1.pdf

  176. @Rational Debate,

    Thanks, I thought they could have calculated the dose from a chest dosimeter. Didn’t know they would have put them in the gloves and boots. There seems to be a safety problem. These workers were standing in the water for three hrs. I would think they would have measured the activity of the water, before doing work. I guess in the rush and given the tiredness of the crews they are taking risks.

    http://www.iaea.org/newscenter/news/tsunamiupdate01.html

    I don’t think you can say it was a thermal burn. The water would not be thermally hot or they wouldn’t be there, especially for that long.

  177. @Steve Elbows

    March 21 – 61℃
    March 23 – 57℃
    March 24 – 73℃
    The power was started to be supplied (15:37 March 24th) and cooling was also started.(18:05 March 24th)

    Something is very odd when you start cooling and the temperature goes up. Don’t know what to make of this. They have already added and could still add water. Maybe that is why the temperature is going up? They haven’t been adding water recently? If that’s the case, I’m sure they can add water and bring the temperature down.

  178. OK, no time after starting cooling to actually bring the temperature down. Maybe they didn’t want to add any more water especially seawater and are going to let the cooling system control the temperature from now on.

  179. Confusion reigns regarding the exposure to the 2 workers.

    Were they working in water? Did they happen to step in some? Was the exposure quoted for whole body, or extremities or feet or lower legs, or skin only? Was the water hot? Were they concerned about inflammation, or were there burns, or was it all precautionary? Was the hospitalization to calm the fears of the workers themselves? Or to help protect the company against any future claims of negligence or negative media stories? Who the heck knows.

    This sort of stuff gets VERY frustrating – and I’m certain that the translation from Japanese to English is adding to the confusion.

    Video of one Japanese official (TEPCO? NISA? I’m sorry, I’ve lost the page), made it sound as if they weren’t working in pooled water, but stepped in some, and that article said that they were sent to the hospital because direct contact of radiation on skin may cause inflammation (um, only if you add a LOT of qualifiers, much of the time zero inflammation would be expected).

    TEPCO just says the skin was contaminated:

    3 workers …..were exposed to the radiation dose of more than 170 mSv. 2 out of 3 are being transferred to the hospital as it was confirmed that their leg skin were contaminated

    Meanwhile, according to this article: http://www.world-nuclear-news.org/RS_Exposures_and_progress_at_Fukushima_Daiichi_240311.html

    basement of the turbine building of unit 3, having to standing in water that resulted in exposures of around 170 millisieverts to the skin on their legs.

    But Kyodo says ( http://english.kyodonews.jp/news/2011/03/80849.html ):

    exposed to radiation amounting to 173 to 180 millisieverts. Two of them were hospitalized due to possible burns to their feet,

    So who the heck knows what the situation is, other than it doesn’t sound as if they got anything greater than 180mSv to the whole body and possibly quite a bit less if the dose reported was actually to the extremity or skin.

  180. considering that 180 mSv are not enough for case skin burning or irritation, while 73°C hot water can cause severe damage to the skin even in very short time , could it be a combination of the two factors?
    i mean, burns from heat and medium to high radiation reading, not necessarily consequent each other?

  181. re post by: William Fairholm, on 25 March 2011 at 8:19 AM said:

    William, & Steve, at some point in the last few days, maybe the 23rd?, they sprayed sea water into the common pool. That has to be factored in. Plus, for the temp after they started ‘cooling’ on the 24th – before I drew any conclusions that way I would want to see the temp reading right before they started. In other words, I’ll bet you that temps were rising, so they sprayed or added some sea water to cool it until power was restored, then power was restored, and the temp you’re seeing from only 21/2 hours after they got electricity back, is just reflecting the temp of the pool immediately before they had power – where the lower temp on the 23rd was reflecting the results of the spraying they did.

  182. re post by: William Fairholm, on 25 March 2011 at 8:23 AM said:

    OK, no time after starting cooling to actually bring the temperature down. Maybe they didn’t want to add any more water especially seawater and are going to let the cooling system control the temperature from now on.

    They would DEFINITELY not want to add more sea water if at all possible. SFP water is some of the cleanest, most pure water you can find anywhere. The water is just crystal clear – so clear that you can’t believe you are looking at the top of fuel rods 30 feet below water. So clear that it is literally difficult to pick out the water line around the edge of the pool. It is kept that clean so that there aren’t minerals or dirt/dust that could get activated by the radiation from the fuel rods. In other words, you minimize the amount of both radiation and contamination you have to deal with that way.

    People joke about it all the time, the ‘blue glow,’ but the Cherenkov radiation is incredibly beautiful, especially if there is a lot of it. Photos don’t begin to convey it…

    If you haven’t already, use google or bing or something and look for photos of nuclear spent fuel pools. Often glare on the lens makes the water look a bit less clear than it really is, but some photos do a decent job at least of giving you some idea, especially if you have a person in the photo so you have some size reference. Think about the clearest ocean water or lake water you’ve seen… typically it’s really clear if you can see something 4 or 5 feet into it. SFP’s, 30 feet and it might as well be nothing between you and what you are looking at, other than of course the refraction shift.

    That’s why so many people were surprised to hear that they’d added any sea water, if the temps in the pool weren’t very high – and the reported temps just didn’t seem that high. Speculation, perhaps an overabundance of caution considering everything that is going on – or worries about ‘what if something happened so we couldn’t get access to it at all for a few days?’ or something like that.

  183. re post by: William Fairholm, on 25 March 2011 at 8:02 AM said:

    Thanks, I thought they could have calculated the dose from a chest dosimeter. Didn’t know they would have put them in the gloves and boots. There seems to be a safety problem. These workers were standing in the water for three hrs. I would think they would have measured the activity of the water, before doing work. I guess in the rush and given the tiredness of the crews they are taking risks.

    http://www.iaea.org/newscenter/news/tsunamiupdate01.html

    I don’t think you can say it was a thermal burn. The water would not be thermally hot or they wouldn’t be there, especially for that long.

    Hi William,

    I hadn’t seen your post when I did mine about ‘confusion reigns’ – so add your IAEA report to the list of somewhat contradictory reports on the issue.

    We just don’t have enough facts – or maybe I ought to say, until we can figure out who’s ‘facts’ are right, and who’s aren’t, we don’t have enough to figure out just what happened here.

    The doses may have come off of dosimetry at chest level, or been calculated from it – just no way to tell.

    Until we know better, I’d withhold any judgment about safety problems or errors. If they knew the workers would be standing in water for 3 hours, someone almost certainly would have checked it first. Its so difficult to say in situations like this, however. Errors do happen of course, they’re human and in a nasty situation trying to work as rapidly as can safely be done.

  184. re post by:

    re post by: BerGonella, on 25 March 2011 at 8:44 AM said:

    considering that 180 mSv are not enough for case skin burning or irritation, while 73°C hot water can cause severe damage to the skin even in very short time , could it be a combination of the two factors?
    i mean, burns from heat and medium to high radiation reading, not necessarily consequent each other?

    Ok, so we don’t really know what happened here or if these workers even got burns, but speaking hypothetically…. Anytime a biological system is exposed to an insult serious enough to cause damage, it can be harder for that system to withstand a concurrent or immediately subsequent insult that is also severe enough to cause damage… so, if I understand your question correctly, then yes, I would think if they’ve got burns it is possible that both things contributed. That said, if the levels of each were too low to seriously harm the skin individually (even if not to the point of burns), then, no, I wouldn’t think it likely that the two together would make any difference.

    I’ve got to either look it up online or pull out one of my old reference books/materials – but I don’t think that radiation burns could even show up this quickly. Erethema, sure, but burns? Meaning, burns but the whole body dose is only 170 mSv when the exposure isn’t from a point source, but a pool of water? I am NOT at all certain of this, but from the first I’ve had this niggling in the back of my brain on this issue.

    On the other hand, if they got the water on their skin, then I wonder if there might not have been a chemical in the water that caused skin irritation (or even burns)… Although I don’t know if that’s a credible supposition either – would any chemical irritants be in the turbine building… or have a pathway from a storage location into the turbine building basement where this occurred…

    Meanwhile, why the heck haven’t we seen any updates on the workers who’ve been injured from the quake, then the tsunami, then the explosions? I mean, TEPCO keeps them listed in terms of the initial injuries, but has anyone seen updates on their conditions? Like the one who was clutching his left chest, or the two who had problems right off being in respirators in the control room, and so on?

  185. Rational Debate:

    I have been around spent fuel ponds and I worked at the research reactor at McMaster, Hamilton, Ontario. Cherenkov radiation is incredibly beautiful. There you can look down at the reactor as it is operating under its shielding water. Even more intense than spent fuel. Yes everything in a reactor uses very pure water. That they had to add seawater must have gone against every instinct they had. Regarding the workers exposed to radiation, I tried to post what you just said. We don’t know enough. No point speculating. My internet went down, so I went and had supper. Back for a while to check up, but I think I’ll go do something else and check back tomorrow to see what else has happened.

  186. @ Rational Debate
    what I was thinking is that their can have being burned by hot (over 50°C water starts to get very dangerous for the skin) salt water, and at the same time they were receiving 170+ mSv. I didn’t want to suggest that radiations worsened the burns, or that the burns somehow weakened skin defences, just that the two facts (burns and radiation exposure) happened in the same time, pushing the physicians to think that the burns were consequence of the exposure.
    I can imagine that 170 mSv very hardly can damage skin, not to say to the extent of burning it, I have no experience of it but this is a very easy to check condition. meanwhile, I had several not too good experience with hot water, like the 99% or more of human beings…

    I beg your pardon, I’m not native english speaking, neither had I studied english, and sometimes I get somehow unclear.

  187. re post by: David B. Benson, on 25 March 2011 at 10:16 AM said:

    Rational Debate, on 25 March 2011 at 9:56 AM — If the common SFP was indunated by the tsunami, then adding more seawater for cooling was probably sensible?

    Hi David,

    I wouldn’t assume that any of the tsunami water got into the common SFP. I suppose it is possible, but I haven’t read of any structural damage to that building, let alone anything serious enough to allow tsunami water into the SFP.

    Even if it had gotten some tsunami water in it, I would think that they would want to avoid adding more if possible. Of course it is all a matter of degree and relative risk, which will vary some depending on who is deciding just what the risks of each scenario are and so on… Obviously they thought it worth spraying/adding sea water that one time, but I’d think they’d work hard to avoid adding more.

  188. re post by: William Fairholm, on 25 March 2011 at 10:25 AM said:

    I have been around spent fuel ponds and I worked at the research reactor at McMaster, Hamilton, Ontario. Cherenkov radiation is incredibly beautiful. There you can look down at the reactor as it is operating under its shielding water. Even more intense than spent fuel.

    It really is, isn’t it?? One of those things that is almost impossible to describe – and all the more awesome when one thinks about how it’s generated, isn’t it? I wish everyone could see it at least once. I’m envious of you seeing it with the research reactor that way. I’ve been around an open pool research reactor years ago, but not while it was operating, so it was just a pool of very very clear water.

    Yes everything in a reactor uses very pure water. That they had to add seawater must have gone against every instinct they had.

    My thoughts exactly.

    I keep being mentally pulled back into thinking about how these workers must feel – at least the ones who normally worked there… I mean, at least in the USA, for decades now nuclear facilities for the most part are extremely clean. Most workers take a great deal of pride being associated with them. So these poor folks, they’re used to going to work every day at this great clean extremely powerful facility, that they take pride in operating safely and producing something so valuable for society (electricity!)… and now presto, the next thing you know it’s a nightmare with holes in the buildings, roofs blown off, high rad levels to worry about, with tsunami debris all over the place too, ancillary facilities just gone…. on top of the horror of all of the quake & tsunami caused utter destruction all around them up and down the entire northern coast. And how many actually lost family or close friends to the tsunami? It’s just unimaginable.

  189. re post by: BerGonella, on 25 March 2011 at 10:38 AM said:

    just that the two facts (burns and radiation exposure) happened in the same time, pushing the physicians to think that the burns were consequence of the exposure.

    Oh! I see what you were asking now. Yes, I would suspect that sort of situation to be entirely possible. At least in the US, and I would imagine in most (all?) countries, most doctors, even excellent ones, have virtually no experience with radiation and little understanding of what is involved.

    Many years ago one of my professors told a story – one of his friends/co-workers cut his hand pretty badly and needed it cleaned and stitched up. The way he injured it got a little radioactive contamination in the wound or on the hand. Not enough to even worry about, beyond of course washing it off. But the cut needed prompt attention.

    They went to the emergency room, thinking this was a simple thing, it was just a cut, even if one that definitely needed stitches. The doctor comes to see it, and they explain what happened.

    The doctor walks off and doesn’t come back for a short time. They figure ok, he had to go get some supplies to do the stitches, or had a patient come in with some more pressing problem.

    Then a short time later, they see the doctor, consulting with a few other doctors – apparently a pretty animated discussion, and the doctors kept looking over at them with very concerned looks on their faces.

    Finally my professor went over to find out what in the world was going on.

    The doctors had decided to amputate the hand, because of the radiation, and they were debating how to best go about doing it!!!

    I don’t recall now if they went elsewhere to get the stitches or talked some sense into the doctors – but this was a very small amount of radiation that wasn’t dangerous to anyone by any stretch of the imagination, and both the prof & the guy with the cut hand were experts in dealing with radiation.

    As to that 170 mSv dose – we really just have to wait and see if that was the dose shown by dosimetry worn at the chest, or if that was the dose to the extremities. If it was chest, then the dose to the feet could have been much higher. No idea off the top of my head if it would be possible under those circumstances for there to be contaminated water that would give a high enough dose for burns at the feet but be 170 mSv at the chest… keep in mind also that if it was 170 mSv at the chest, that dose almost certainly includes dose that came from other sources than the water also. Even if it was just walking from outside to get to the turbine building.

    I beg your pardon, I’m not native english speaking, neither had I studied english, and sometimes I get somehow unclear.

    English is my first language, and *I* manage to not be clear at times too. You are doing great.

  190. Rational Debate, on 25 March 2011 at 8:36 AM said:

    Confusion reigns regarding the exposure to the 2 workers.

    Were they working in water? Did they happen to step in some? Was the exposure quoted for whole body, or extremities or feet or lower legs, or skin only? Was the water hot? Were they concerned about inflammation, or were there burns, or was it all precautionary? Was the hospitalization to calm the fears of the workers themselves? Or to help protect the company against any future claims of negligence or negative media stories? Who the heck knows.

    This sort of stuff gets VERY frustrating – and I’m certain that the translation from Japanese to English is adding to the confusion.

    They were working in standing water laying electrical cables under reactor #3 turbine building, and the water spilled over the top of their boots and came into direct contact with their skin causing beta burns. Precautions to protect their health were taken.

    http://english.kyodonews.jp/news/2011/03/80799.html

    http://news.yahoo.com/s/ap/as_japan_earthquake

    It’s Japan (and a different media culture) … they aren’t as obsessed as we are with every little nuance, tidbit of political intrigue, assigning responsibility, angles, ideological posturing, and all the rest.

  191. Steve Elbows wrote:

    “Can anybody say more about the neutron beam stuff which as far as I know so far has only been discussed in one Kyodo news story?

    I always found this statement a little troubling and difficult to integrate. It appeared for several days in status updates from official accounts. Nobody in the press has followed up on it. Regarding Reactor 4 Spent Fuel Pool: “renewed nuclear chain reaction feared at spent-fuel storage pool.”

    http://english.kyodonews.jp/news/2011/03/80227.html

  192. EL, on 25 March 2011 at 12:38 PM said:
    “They were working in standing water laying electrical cables under reactor #3 turbine building, and the water spilled over the top of their boots and came into direct contact with their skin causing beta burns”

    Well, that puts that one to bed. Direct contact with a beta emitter would cause burns. That is a lot of water they were standing in. I don’t think a dosimeter even one in their boots would be calibrated for that type of contact.

  193. The Asia Sentinel as posted an article on the website called the The Roots of Fukushima
    http://www.asiasentinel.com/index.php?option=com_content&task=view&id=3083&Itemid=227

    Includes the following quote from Chiro Okuba, lifetime Toshiba engineer:

    “We didn’t take a tsunami into account” in planning for an emergency, says Okubo, who spent his career with Toshiba, one of Japan’s principal nuclear power constructors. Only when he was near retirement, he says, did he hear some concerns being raised about impact of a tsunami on nuclear plant safety.”

    It then goes on to the following conclusion:
    “That is a strange lapse. When the plant was being designed and built in the late 1960s, the famous Chilean Earthquake in 1960 was fresh in people’s mind. It was the largest earthquake of the 20th century, measuring 9.5 on the Richter scale. It set off a huge trans-Pacific tsunami that hit northeastern Japan, same area as this month’s quake, killing 195 people.

    The first unit was built by the American company General Electric, which pioneered the type of power plant known as a boiling-water reactor. Later units were built by Toshiba and Hitachi but using American plans. “We just copied the US blueprints,” says Okuba, without trying to adapt them to conditions specific to Japan.”

    The early designs presumably did not factor in a tsunami, since such an event is not widely feared in the US except in Hawaii, where there are no nuclear power plants. Early American designs were sited inland, and even today only two plants are sited on the Pacific coast in California.”

    Wonder what the coments from the posters here is to this type of reporting?

  194. Rational Debate, on 25 March 2011 at 11:30 AM said:

    I’ve been around an open pool research reactor years ago, but not while it was operating

    Suposedly with the lights turned off, you could easily read by the Cherenkov radiation at the McMaster reactor. Never saw it with the lights off, but all the water around the reactor was glowing brightly.

  195. > Kyodonews … renewed chain reaction

    I think they’re presenting stuff in chronological order. Google the phrase quoted– that story is identibal back to March 17th. Likely they just add a bit of news to the bottom of each paragraph each day. Can’t imagine what else this could mean.

  196. John Smith, on 25 March 2011 at 2:44 PM said:

    The Asia Sentinel as posted an article …. Wonder what the coments from the posters here is to this type of reporting?

    Hi John,

    To answer your question, I wouldn’t put much stock in it. It sounds very much as if it is trying to sensationalize things, capitalize on people’s desire to have someone to blame, right or wrong, whenever disaster strikes.

    Why do I say that? Because right off the bat the site has a 5 meter tsunami wall. If the design didn’t consider tsunami, where’d the wall come from?

    Note also the article says:

    The early designs presumably did not factor in a tsunami, since such an event is not widely feared in the US…

    This sounds like nothing more than sheer speculation to me. It would tweak my interest slightly, in that sure, I’d be curious to know just what the initial designs actually did or didn’t consider this way. But anything short of someone actually reviewing the relevant design documents including the siting evaluation, specs, etc., and I’m not buying it.

  197. re post by: William Fairholm, on 25 March 2011 at 2:46 PM

    I’m impressed!! Wouldn’t that be something?! I’m assuming that the reactor was one you could run continuously for a little while, not a one shot at a time sort of thing?

  198. Ok, with only a little quick checking (e.g., no in depth research, so tentative), it seems that any beta ‘burns’ couldn’t possibly have manifested yet. It appears that some itching and redness might appear a few hours after the exposure – burns (blistering, peeling, ulceration, etc) take quite a bit longer.

    I probably shouldn’t even be speculating, but I’m guessing that they were rightly concerned about the possibility of beta burns, and sent them for decontamination. But that there weren’t any actual burns. Hopefully none will develop either. If they did have burns, then to me it sounds as if they would have to be thermal or chemical.

    The following from the US Center for Disease Control:

    CRI can
    occur with radiation doses as low as 2 Gray (Gy) or 200 rads2 and the severity of CRI symptoms will
    increase with increasing doses. Most cases of CRI have occurred when people inadvertently came in
    contact with unsecured radiation sources from food irradiators, radiotherapy equipment, or well depth
    gauges. In addition, cases of CRI have occurred in people who were overexposed to x-radiation from
    fluoroscopy units.

    Early signs and symptoms of CRI are itching, tingling, or a transient erythema or edema without a history
    of exposure to heat or caustic chemicals. Exposure to radiation can damage the basal cell layer of the skin
    and result in inflammation, erythema, and dry or moist desquamation. In addition, radiation damage to
    hair follicles can cause epilation. Transient and inconsistent erythema (associated with itching) can occur within a few hours of exposure and be followed by a latent, symptom-free phase lasting from a few days to several weeks. After the latent phase, intense reddening, blistering, and ulceration of the irradiated….

    If the exposition to beta radiation is intense, the beta burns may first manifest in 24–48 hours by itching and/or burning sensation that last for one or two days, sometimes accompanied by hyperaemia. After 1-3 weeks burn symptoms appear; erythema, increased skin pigmentation (dark colored patches and raised areas), followed by epilation and skin lesions. Erythema occurs after 5–15 Gy, dry desquamation after 17 Gy, and bullous epidermitis after 72 Gy.[3] Chronic radiation keratosis may develop after higher doses. Primary erythema lasting more than 72 hours is an indication of injury severe enough to cause chronic radiation dermatitis. Edema of dermal papillae, if present within 48 hours since the exposition, is followed by transepidermal necrosis. After higher doses, the malpighian layer cells die within 24 hours; lower doses may take 10–14 days to show dead cells….. (link at the bottom of this post as it’s very long)

    ~~~~~

    and this is wikipedia (which I always take with a huge grain of salt, link at end of post):

    * In first degree beta burns the damage is largely limited to epidermis. Dry or wet desquamation occurs; dry scabs are formed, then heal rapidly, leaving a depigmented area surrounded with irregular area of increased pigmentation. The skin pigmentation returns to normal within several weeks.
    * Second degree beta burns lead to formation of blisters.
    * Third and fourth degree beta burns result in deeper, wet ulcerated lesions, which heal with routine medical care after covering themselves with dry scab. In case of heavy tissue damage, ulcerated necrotic dermatitis may occur. Pigmentation may return to normal within several months after wound healing.[3]….

    The acute dose-dependent effects of beta radiation on skin are as follows:[9]
    0–6 Gy no acute effect
    6–20 Gy moderate early erythema
    20–40 Gy early erythema in 24 hours, skin breakdown in 2 weeks
    40–100 Gy severe erythema in less than 24 hours
    100–150 Gy severe erythema in less than 4 hours, skin breakdown in 1-2 weeks
    150–1000 Gy blistering immediate or up to 1 day

    According to other source:[10]
    2–6 Gy transient erythema 2–24 h
    3–5 Gy dry desquamation in 3–6 weeks
    3–4 Gy temporary epilation in 3 weeks
    10–15 Gy erythema 18–20 days
    15–20 Gy moist desquamation
    25 Gy ulceration with slow healing
    30–50 Gy blistering, necrosis in 3 weeks
    100 Gy blistering, necrosis in 1-3 weeks

    As shown, the dose thresholds for symptoms vary by source and even individually. In practice, determining the exact dose tends to be difficult… ”

    http://docs.google.com/viewer?a=v&q=cache:ScyCAliyXmEJ:www.ametsoc.org/stationscientist/documents/criphysicianfactsheet.pdf+time+to+onset+of+erethema+from+beta+radiation&hl=en&gl=us&pid=bl&srcid=ADGEESjosi3CFQw5vtblyAWN57IyJhTCfSW3qoKvftM90FSTKRLJfhkuYCJFoBAT-HtLtQpwytrxVJaVgY1Pncw6e_f1B6IMcVwSzzDwRWf8ZcY0H_TxBIoZ08dZuQB-IgvgIAT9OSJ6&sig=AHIEtbS8BnJupASys3PPDzjTTATpilaugQ

    http://www.google.com/url?url=http://en.wikipedia.org/wiki/Radiation_burn%23Beta_burns&rct=j&q=radiation+beta+burns&usg=AFQjCNGTplDUc2q_Vw_hXShq8BHw-Fb8qw&sa=X&ei=ljuMTfrnLcmTtweXu-GqDQ&ved=0CCUQygQwAA&cad=rja

  199. TEPCO believes the tsunami that inundated the Fukushima Daiichi site was 14 meters high, the network said. The design basis tsunami for the site was 5.7 meters, and the reactors and backup power sources were located 10 to 13 meters above sea level. The company reported that the maximum earthquake for which the Fukushima Daiichi plants were designed was magnitude 8. The quake that struck March 11 was magnitude 9.

    I think there is some inconsistency here in the observations made by TEPCO and those made by the Japanese Meterological Agency (which measures and provides real time monitoring for tsunamis). There are three ways of measuring the height of tsunami waves:

    1) height at the shore (wave height).
    2) depth of water above sea level (buoy height at sea).
    3) highest elevation at maximum inundation distance (run up height).

    Wave height (1) and run-up height (3) are two different things. And both are impacted by different characteristics of the ocean floor, coastline, and dry land grade (as much as the energy contained in the wave). When creating a sea wall as a defense against a tsunami wave, it seems one is most concerned with the wave height (or even perhaps buoy height if the water is deep enough). TEPCO appears to have given us the run up height, or the elevation of the wave above sea level at the maximum inundation distance (which is different from the two other measures). If the ocean floor is deep near the shore, the wave will have a high velocity, and will travel farther up the shore. If it the ocean floor is shallow, the wave will decrease in velocity, and not travel as far. It’s possible that a 6.5 meter sea wall can contain a wave that would travel to a much greater height in it’s run up elevation? A wave on shore is also not nearly as high as a wave in deeper water (where a sea wall may be placed). Anybody handy in doing some advanced wave and shoreline calculations. Tsunami is a Japanese word, after all, they should be pretty good at these things. Basically, I’m looking at the Japanese Meterological Agency measurements, and realizing that something doesn’t add up?

    http://www.jma.go.jp/en/tsunami/observation_04_20110313180559.html

    Nothing has been documented greater than 7.3 meters yet. We’ll have to keep an eye out and see if these numbers are updated.

  200. Japanese nuclear safety officials said Friday that they suspect that the reactor core at one unit of the troubled Fukushima Dai-ichi nuclear power plant may have breached, raising the possibility of more severe contamination to the environment.

    “It is possible that somewhere at the reactor may have been damaged,” said Hidehiko Nishiyama, a spokesman for the nuclear safety agency. But he added that “our data suggest the reactor retains certain containment functions,” implying that the damage may have occurred in Unit 3’s reactor core but that it was limited.

    Operators stopped work Friday at units 1 through 3 to check on radiation levels.

    More at:
    http://www.cbsnews.com/stories/2011/03/24/501364/main20047058.shtml?tag=stack

  201. I assume the levels of radiation in the water the workers stepped in is stupidly high and is the cause for renewed concerns about reactor 3 containment?

    “The company says 3.9 million becquerels of radioactive substances per cubic centimeter were detected in the water that the workers were standing in. That is 10,000 times higher than levels of the water inside a nuclear reactor in operation.

    The level of radioactive cerium-144 was 2.2 million becquerels. Also, 1.2 million becquerels of iodine-131 was measured. These substances are generated during nuclear fission inside a reactor.”

    http://www3.nhk.or.jp/daily/english/25_10.html

  202. Note that strong worries about containment in reactor 3 have already been raised yesterday (March 24th 0.00 am Japan time) by the French “institut de radioprotection et de sécurité nucléaire”

    http://www.irsn.fr/FR/Actualites_presse/Actualites/Documents/IRSN_Seisme-Japon_Point-situation-24032011-08h.pdf

    (my unprofessional translation) :

    “Important smoke emissions have been noticed on this reactor. The IRSN is working on an analysis of potential causes of a breach of confinement at reactor 3. One of the hypotheses in consideration is the eventuality of a breach of the pressure vessel followed by an interaction between corium and concrete at the bottom of the secondary confinement”.

    According to the French journalist Sylvestre Huet, “According to an engineer at the IRSN, this “hypothesis” must be understood as an anticipation of situation worsening”

    http://sciences.blogs.liberation.fr/home/2011/03/fukukshima-danger-accru-au-r%C3%A9acteur-3-%C3%A9vacuation-sur-30-km.html

  203. Alain, on 25 March 2011 at 8:37 PM said:

    Note that strong worries about containment in reactor 3 have already been raised yesterday (March 24th 0.00 am Japan time) by the French “institut de radioprotection et de sécurité nucléaire”

    Integrity of the reactor vessels of units 1-3 has been listed as unknown for at least a week on the JAIF reactor status reports. Damage has been listed as suspected on unit 2 primary containment for just as long. They have had various descriptions of the containment on unit 3, including the odd ‘Might be “Not damaged”‘ It is currently listed as Not Damaged. So damage has been suspected, but not confirmed for a long time. Now hopefully they are starting to get better instrumentation and Unit 3 containment may go back to damage suspected or confirmed. I await developments, but was not surprised that there may be some failure of the containment system.

    JAIF reports can be found at: http://www.jaif.or.jp/english/

  204. A slightly more elaborated report on the event…

    Three workers were in the ankle-deep water Thursday and were carrying dosemeters. But they ignored the high-radiation warnings of the devices and continue repair work in the soaked basement of the No. 3 reactor’s turbine building, officials of Tokyo Electric Power Co., the plant operator, said.

    The water was about 15 centimeters deep, officials said.

    “I thought (the dosemeter) was out of order,” one of the workers was quoted as saying. The radioactivity level had been low in the basement before.

    Two of the workers were rushed to a hospital in Fukushima city Thursday. They were taken Friday to the National Institute of Radiological Sciences in Chiba for examinations and treatment for – possible beta ray radiation burns – below their knees.

    According to TEPCO and the Nuclear and Industrial Safety Agency (NISA), the water was found with 3.9 million becquerels of radioactive substances per cubic centimeter, about 10,000 times the level of water used to cool reactor cores.

    Cobalt-60, iodine-131, cesium-137 and other substances, which do not normally exist in cooling water, were detected, the officials said.

    http://www.asahi.com/english/TKY201103250202.html

  205. That’s not just beta sources then. That’s direct contact with anything water-soluble out of the core that’s washed down to the basement–cobalt 60 is a gamma source.

    Crap. Nobody told these guys that if they think the dosimeter is out of order they should leave the area first and check that??

  206. > cerium-144

    Not good. I wonder if vented steam condensing inside the building could have carried this up then down to the basement.

    http://www.nature.com/nature/journal/v211/n5054/abs/2111179a0.html

    “CERIUM-144 is a high yield (approx 5 per cent) product of nuclear fission that can be readily detected in debris from fission reactions. From about the first to the fourth year after fission, cerium-144 contributes most to total radioactivity1. Because each nuclear disintegration of cerium-144 and its daughter praseodymium-144 can result in deposition of the effective equivalent of more than 6 MeV in bone2, cerium-144 ranks among the more hazardous fission products. …”

  207. Argh. http://www3.nhk.or.jp/daily/english/25_29.html

    “… the water sample indicated it is highly likely the leak comes from the reactor itself, not from the pool storing spent nuclear fuel.
    … it is highly possible that radioactive materials are leaking from somewhere in the reactor.
    … high levels of radiation have been measured at reactors No. 1 and 2, and speculates there may also be leakage from them. Cooling operations using seawater are continuing at the reactors….”

  208. @Shelby:

    I’m actually surprised there hasn’t been more of these events given, the seriousness of the situation, the stress the workers have been under and length (2 wks) this has been going on. Tepco managers seems to be doing a good job of limiting exposure given all they have to deal with.

  209. I have said it before and I’ll say it again, I think they will have to flush most of this radioactive water out to sea given the volumes involved. The normal way to remove radioactive material from water is to use ion exchange resins to remove the radioactive isotopes. These are used in normal operation to remove the small amount of radioactive material (neutron induced and fission products) that is mobilized. Whether the resins could handle this load is not even relevant, because they would be swamped by the seawater. Evaporation followed by burial somewhere? That would be much worse, even if possible. Dilution, dilution, dilution is the only solution.

  210. The water analysis certainly speaks of fuel damage somewhere, with a path to release. I guess the fisison products are more mobile because they’ve broken free of the stable oxide that the fuel itself is in – assuming that the absence of actinides in the TEPCO analysis summary means they weren’t present in meaningful quantities. Which perhaps implies a cladding failure but not wholesale fuel rod burn/collapse – jumping quite a long way on not much information.

  211. @Joffan,

    Yes they should be able to detect any actinides in their sample, so the lack is encouraging. That doesn’t mean there aren’t fuel pellets that have accumulated at the bottom of the reactor. Oxides of the actinides have low or essentially zero solubility in water (from my CRC handbook). There may be some chlorides formed given the heat and salt water and they have some solubility, but I don’t know how likely that is.

  212. Cited again, here is the specific report of nuclides found in the water. Nuclear export with the Times reports that high levels of radioactive cobalt and molybdenum point to long standing corrosion problems at the plant (and concerns with the extended use of sea water): “Both materials typically occur not because of fission but because of routine corrosion in a reactor and its associated piping over the course of many years of use.”

    The fact of the matter, we wouldn’t be talking about any of this (including additional concerns about reactor containment) had these workers (subcontracted and poorly trained by TEPCO) not stuck their feet in the water.

  213. Hank Roberts, on 26 March 2011 at 3:24 AM said:

    bioaccumulation

    I assume that was a reference to my assertion about dilution. I didn’t say it was a good solution, I just don’t know what else they are going to do. I hope they come up with one, but I can’t see what it is going to be.

  214. EL, we might still have been talking about this even with better training of the affected workers. The radioactive water was still there, and once the workers’ dosimeters were checked as OK (which they were), the response team would have had to find the cause.

  215. I must say that I’m astonished that 2 weeks out, there is still not someone in the nuclear industry running an active blog/timely of breaking reports. It’s crazy that we have to go out and forage google for stories than bring them back here and post them. It’s a very arcane way to build a data/timeline in the 21rst century. I’m grateful to have this blog comments section to share links and opinions, but the BNC blog itself is not a timely source of data / timeline / reports. Back to foraging Google I go……

  216. Why are all my comments awaiting moderation before they get posted? Are you really that afraid of my brain? Stop this nonsense.
    MODERATOR
    You are on moderation because of various violations of the commenting rules. One of your posts held overnight for moderation has already been edited for linking to an article which did not support your personal opinion/unsupported hearsay.]

  217. @Steve Elbows

    I find that results for Cl-38 very puzzling in that report you linked to. The activity is very high, but the only way to get Cl-38 is from the neutron activation of Cl-37 (nat. abundance of 24.5%). The half-life is 37.4 min. so it would have to of been recently produced, which would mean there is nuclear fission producing neutrons going on in that reactor as we speak.

  218. William Fairholm, on 26 March 2011 at 7:30 AM said:

    @Steve Elbows

    I find that results for Cl-38 very puzzling in that report you linked to. The activity is very high, but the only way to get Cl-38 is from the neutron activation of Cl-37 (nat. abundance of 24.5%). The half-life is 37.4 min. so it would have to of been recently produced, which would mean there is nuclear fission producing neutrons going on in that reactor as we speak.

    —-

    Perhaps we should return to the ignored question of where those 13 neutron beams observed by TEPCO came from?

  219. @Steve Elbows

    I see how we differ. The 19s is for a metastable state above the ground sate. I don’t know what percentage of each state is produced in nuclear fission, but the 19s state would be gone before it could be measured outside the reactor.

  220. William Fairholm, on 26 March 2011 at 8:07 AM said:

    Regardless, the presence of Cl-38 is very concerning as there is only one conclusion. Nuclear fission is occuring in this reactor.

    ———

    Perhaps we should return to the ignored question of where those 13 neutron beams observed by TEPCO actually came from?

  221. Concerns about Reactor No. 3 have surfaced before. Japanese officials said nine days ago that the reactor vessel may have been damaged.

    Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, mentioned damage to the reactor vessel on Friday as a possible explanation of how water in the adjacent containment building had become so radioactive.[deleted unsupported hearsay presented as fact - link supplied did not contain this information] http://www.nytimes.com/2011/03/26/world/asia/26japan.html?hp

  222. The only thing that could produce As-74 by neutron activation is Ge-73 (7.76% nat. abundance) which has a fairly large neutron cross-section of 14 barns. But where would germanium come from? It isn’t in stainless steel is it? Or any other reactor component.

  223. I spent many years as a process troubleshooter in the petroleum industry. I learned that when faced with analytical results that seemed unusual, you always had to suspect the lab results too.

    A second or a third sample is called for in those cases. Even then, lab methods can have interferences, and we would have to submit a standard sample to see what the lab would say.

    Maybe nuclear analytical methods are much better, but when faced with unusual results, don’t jump to conclusions, instead recheck.

  224. @Leo Hansen

    Yes, I agree. Just this was so odd. And it would seem they were looking for Cl-38 activity unless there is some automatic software that is converting gamma ray energies into assigned nuclei which got confused. But I agree it must be checked. By the way, here is a better mass yield curve which shows how little atomic mass 74 is produced in fission. It is off the logarithmic chart.

    http://www.science.uwaterloo.ca/~cchieh/cact/nuctek/fissionyield.html

  225. Pingback: Fukushima Daiichi Nuclear Accident – 26 March status « BraveNewClimate

  226. @Joshua

    Cs-134 from thermal neutron fission of Pu-239, and Pu239 will always be present at some level in a LWR due to neutrons on fertile U-238.

    Mo-99 from thermal U235 fission: direct yield of 7.7×10-4, accumulated yield of 6.1×10^-2.

    So Tc-99m from Mo-99 beta decay: 65.9 hrs: invented at BNL, where I work, sometimes :)

    The Technetium-99m Generator

  227. @Rational Debate

    Thanks for your great summary of the variety of reactor designs, I’m working my way through the links and indeed having fun learning about all the different designs!

    I’m a theoretical physicist, mostly a particle physicist but with some training in nuclear physics, and I have not much experience with nuclear reactors, beyond knowing some of the general principles on which they operate, and having seen the insides of research reactors. So terms like Gen I,II,III,IV were opaque to me, and the state of the power generation industry and plans for the future were unknown to me. So I found your post a very useful intro.

    I may get back to you with some questions in a more appropriate thread.

  228. re post by: David Kahana, on 26 March 2011 at 4:28 PM:

    You are certainly welcome David! I’m glad my post was useful – and especially that you are having fun checking out the various designs and so on. I know it’s something that I’ve always been intrigued by myself and have kept an eye on over the years. :0)

    I’ll be happy to answer anything I’m able to. Right now, it would seem that the “open thread” is one where almost anything can be discussed. http://bravenewclimate.com/2011/03/21/fukushima-open-discussion/#comment-121156

  229. Well, this isn’t sounding good… kyodo news has a scrolling banner “news advisory” saying ‘High radiation suspends work to fix Fukushima plant’s No. 1 reactor” http://english.kyodonews.jp/news/japan_nuclear_crisis/

    JAIF’s latest update, meanwhile, includes the following two items. I’ve added bold to the second part, which would seem to indicate that they’ve given up restoring normal cooling systems to any of the units… I’m sure there will be more news forthcoming, and hopefully this is just something temporary (report no. 30 http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301116660P.pdf )

    ** It is found that water accumulated at the basement of the turbine building of
    unit-1and 3 contains radioactive material 10,000 times as much as it in water
    in reactor at normal operation. TEPCO took immediate action to drain off
    this water since current situation would cause delay in recovery work. (11:35, March 26)

    **Fukushima Daiichi nuclear power station has been in serious condition since
    some units lost cooling function. TEPCO is trying to recover components for
    cooling that should be driven by external AC power. However, working
    condition in high radiation area is so bad and there is no prospect of
    accomplishing the work for this recovery.
    (05:15, March 26)

  230. David Kahana, on 26 March 2011 at 4:31 PM said:

    The Cl-38 seems crazy.

    The more I think about it the crazier it seems. The neutron cross-section of Cl-37 is 430 millibarns, which isn’t small, but isn’t large either. To work back from the observed activity, through the delay before measurement, through the transport mechanisms, to the neutron flux that would produce this activity, to the fission rate that would produce this neutron flux, would be very complex and fraught with uncertainties. Much easier to get another “confirming” measurement, done very carefully, to see if this is a real problem.

  231. One of the frustrating things about the situation in Japan is that we get reports that suggest that alarming things are happening in Japan, like the Cl-38 activity which suggest fission continuing in the core and the observation of neutron flux in areas around the plant which suggests there is Pu-240 that has escaped, but then no follow up reports. These would be serious problems if true. You would think they would follow up and find out if these are true problems. But then nothing follows. Maybe they find there are no problems and so no need to report a non-problem, but it is frustrating to be left hanging with no further information.

  232. @Rational Debate

    There are no elements let alone reactor components that could be a source other than Cl-37. You would have to get into two or more neutrons being absorbed. Not going to happen, especially versa the Cl-37 we all ready know is there. Either bad measurement or fission was active in the core shortly before the the water was released to the turbine building.

  233. From the latest JAIF earthquake report:
    “high radiation level in the water was also found in the basement of the turbine building of Unit 1, 2 and 3. The level of radiation on the surface of water was more than 1000 millisieverts (mSv) per hour in Unit-2, 60mSv in Unit-1, 750mSv in Unit-3. NISA officials believe the contaminated water likely came from the reactor rather than the spent fuel pool because the radionuclide detected contained in the fuel and some had short half-lives. TEPCO took immediate action to drain off the water because current situation would cause delay in recovery work. TEPCO already started draining off the water in Unit-1, and also preparing or considering drain off the water in Unit-2 and -3. The water would be sent to
    condensers in the turbine building.”

    http://www.jaif.or.jp/english/aij/member/2011/earthquakereport32.pdf

    Wow. Those are very high levels. Where are the condensers and how much water can they store there? This has to eventually go to the sea as more water continues to leak. Must be lots of damage to the fuel.

  234. From the lastet JAIF reactor status report, the temperature of the SFP 2 is high. 71℃ (26th 21:00)
    70℃ (27th 05:00)

    http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1301210659P.pdf

    They must not have any cooling going on and are adding water to make up for evaporation. They also list the temperature of SFP 4 as being immeasurable since the 24th, 11:00. No note on SFP 3 temperature. Last information on saw on SFP 1, the temperature was around 50℃ and that was for several days. SFPs 5 and 6 are fine.

  235. Exposure levels have been estimated for those workers who received large doses of radiation. From the IAEA report “the level of local exposure to the workers legs was estimated to be between 2 and 6 sieverts.” Those are definitely radiation burns. How they go from local exposure to whole body dose I don’t know how to calculate, but I would think they have exceeded the 250mSv they are allowed to receive even in this emergency situation, especially given that they were also receiving a whole body dose from that water they were standing in. I would expect long term health consequences for these workers.

    http://www.iaea.org/newscenter/news/tsunamiupdate01.html

  236. Whoah, William Fairholm — you’re leaping from a couple of facts quoted then making statements: A quoted “‘estimated to be between 2 and 6 sieverts'” then a leap into opinion phrased as fact: “Those are definitely” then speculation: ‘I don’t know how to calculate but would think” and “I would expect” — and earlier “they must not have any cooling ….”

    Can you give some basis for these beliefs? They don’t follow clearly from the bit of fact you give first.

  237. @Hank Roberts

    I used definetly radiation burns, because they are estimating the exposure to their legs from the damage done to them or that is my reading of this report. I emphasied that because there was earlier speculation on hot water burns. Levels of 170 mSv exposure were reported for these workers which I take to be from their dosimeters. Adding the direct contact exposure to their legs at such a high level, I think it is reasonable to get to near or above 250 mSv total exposure without doing the full analysis. I think this is less speculative than that on a lot of the information we have been receiving, but that is my reasoning and you may disagree with it .

  238. re posts by, 1st one: William Fairholm, on 28 March 2011 at 1:33 AM said:

    ….

    “the level of local exposure to the workers legs was estimated to be between 2 and 6 sieverts.” Those are definitely radiation burns.

    No, they’re not definitely radiation burns. If they had erethema, it could also be from water temperature or from chemicals in the water – it could even be from a reaction by the skin to harsh detergents that are often used to wash anti-contamination garments which were then brought into close contact with the skin when the anti-c’s got wet. We’ve seen that before – it can be very surprising what can cause even very nasty looking bright red skin.

    It also very much sounds as if they are estimating the dose from how the skin looked – a mistake, because as noted, too many other things can cause skin reddening too. It also doesn’t fit with the reported surface dose rate of the water.

    So we have a number of factors here that don’t match up. That means that actions should have been taken, rapidly to try to clear up some of the key factors. In other words, a couple of samples of the water that are then analyzed thoroughly.

    Even if we take the new reports of the water, it was 750 – which still doesn’t give a high enough dose. So, we don’t know. They might, they may have better information by now, but it wasn’t released in this report. We still have no idea if there are any radiation burns.

    but I would think they have exceeded the 250mSv they are allowed to receive even in this emergency situation, especially given that they were also receiving a whole body dose from that water they were standing in. I would expect long term health consequences for these workers.

    The whole body dose was recorded by the dosimeters, and was 170-180 mSv. They may do more detailed dose reconstructions if they can, and that may increase it some, but I see no reason to assume that it was over 250 – let alone that it was high enough to expect any health effects unless you are meaning a possible (not certain) calculated incremental increase in cancer risk many years down the road. That, possibly. Any immediate health effects? Very unlikely if chest dosimeters readings were 170 mSv.
    MODERATOR
    This conversation is starting to ramble off topic. Please continue this discussion on Fukushima Open Thread 2 or the posts will be deleted and you will be asked to re-post.

  239. @Rational Debate

    I’m glad you think your assessment is better than the “National Institute of Radiological Sciences in the Chiba Prefecture” mentioned in the item, but let me be sceptical of your expertise and conclusion especially since you didn’t examine them or know the circumstances of their assessment and treatment. I will take their assessment as given until different information arises. The long term consequences that I know of are mainly increased cancer risk, but I didn’t exclude any other, because I haven’t read extensively on the matter. We can quibble over what their total exposure is, I wasn’t trying to make that definitive, just a best guess.
    MODERATOR
    This conversation is drifting away from this thread and into the Open Thread arena. Please switch to Fukushima Open Thread 2 to continue discussion.

  240. William Fairholm, you’re mixing up direct quotes with statements of belief.

    Please stop doing this. Cite your sources, quote them directly, use quotation marks around the quotes.

    Put “I think” or ‘In my opinion” before other statements.

    This is an exact quote with enough context to understand it:

    “For two of the three workers, significant skin contamination over their legs was confirmed. The Japanese authorities have stated that during medical examinations carried out at the National Institute of Radiological Sciences in the Chiba Prefecture, the level of local exposure to the workers’ legs was estimated to be between 2 and 6 sieverts.”
    From:
    http://www.iaea.org/newscenter/news/tsunamiupdate01.html

    Everything else is speculation.

  241. @Hank Roberts

    Maybe as matter of style I chould use longer quotes, but I have used quote marks, and I thought the reference was obvious in context. I assume that people have read the link and are following the context, but I could see as people dip in and out of these thread, they may not see that.

  242. Early I made a statement that they were not cooling SFP 2. Although I believe that was correct, I decided to look back at all the temperature records in the last 25 JAIF reactor status reports. This seems to be a temporary condition. They may have had to turn it off for a while for some reason. I shouldn’t have stated they had to add water. They seemed to have turned it back on given the last temperature reading. Here is the record for the Temperature of Unit 2 SFP.

    Temp. Date/time
    67℃ (27th 09:00)
    70℃ (27th 05:00)
    71℃ (26th 21:00)
    57℃ (26th 13:00)
    57℃ (26th 9:30)
    52℃ (25th 23:00)
    50℃ (25th 18:00)
    28℃ (25th 10:00)
    28℃ (25th 06:00)
    40℃ (24th 17:00)
    45℃ (24th 13:00)
    52℃ (24th 01:00)
    51℃ (23rd 04:20)
    51℃ (22nd 23:00) 22nd 16:07-17:01 Water injection to SFP was conducted (about 18 tons).
    53℃ (22nd 11:20)
    51℃ (22nd 06:00)
    50℃ (21st 14:25)

    On the March 20 22:00 report the following first appears in red:
    “20t 15:05, operation of seawater injection to the spent fuel pool was conducted”
    They do not attach a date to this event in the log, but since it first appeared in the report of this day, I assume this is the date it occurred. This is separate from the adding of water on the 22nd, which I believe is fresh water.

    Sources found at http://www.jaif.or.jp/english/

    While doing this I also compiled information on Units 5 & 6.

    Temperature of Unit 5 & 6 SFPs
    Unit 5 Unit 6 Date/time
    37.8℃ 21.0℃ (27th 14:00)
    34.6℃ 20.5℃ (27th 06:00)
    43.7℃ 29.0℃ (26th 11:00)
    42.8℃ 30.0℃ (26th 14:00)
    43.7℃ 29.0℃ (26th 11:00)
    42.3℃ 27.0℃ (26th 06:00)
    38.8℃ 23.8℃ (25th 20:00)
    37.9℃ 22.0℃ (25th 18:00)
    39.5℃ (25th 10:00)
    49.3℃ 20.0℃* (25th 06:00)
    50.9℃ (25th 01:00)
    49.0℃ (24th 17:00)
    47.7℃ 27.0℃ (24th 13:00)
    45.1℃ 23.5℃ (24th 05:00)
    42.6℃ (23rd 22:00)
    41.1℃ 19.0℃ (23rd 18:00)
    39.0℃ 19.5℃ (23rd 14:00)
    39.0℃ 20.0℃ (23rd 12:00)
    37.8℃ 20.0℃ (23rd 09:00)
    36.6℃ 21.0℃ (23rd 06:00)
    34.2℃ 24.5℃ (23rd 00:00)
    33.5℃ 27.5℃ (22nd 17:00)
    37.5℃ 25.0℃ (22nd 11:00)
    37.4℃ 23.5℃ (22nd 08:00)
    35.8℃ 30.0℃ (22nd 01:00)
    42.3℃ 36.5℃ (21st 17:00)
    42.3℃ 36.0℃ (21st 16:00)
    39.5℃ 32.0℃ (21st 05:00)
    35.1℃ 28.0℃ (20th 16:00)
    36.1℃ 36.5℃ (20th 09:00)
    40.1℃ 52.0℃ (20th 03:00)
    67.6℃ 65.0℃ (18th 22:00)
    65.5℃ 62.0℃ (18th 15:00)
    65.9℃ 63.0℃ (18th 08:00)
    * Average of two different numbers on two consecutive reports, 19.5℃ and 20.5℃

    They do not list temperatures for Unit 1, but I’ve seen numbers elsewhere of around 50℃, a few days ago. I could track it down if people are interested, I posted the link earlier.

    For Unit 4 they list “Unmesurable (since 14th 04:08)” or later reports “(24th 11:00) (immeasurable)”

    For Unit 3 SFP, I didn’t see any mention of temperature, but I might have missed one.

  243. Shelby, on 27 March 2011 at 11:34 PM said:

    William
    I keep bringing up the 13 neutron beams that Tepco reported observing from 1.5km away (starting on March 13th) to support your fission concerns. The report was a blip on the screen then it was erased from the news cycle with no real explanation. My understanding is only fission can cause neutron beams of that size

    Sorry Shelby, I`ve been distracted by other matters. I have dealth with this earlier. Starting at William Fairholm, on 24 March 2011 at 5:00 AM said:

    Let me be clear, the issue of neutron counts outside the reactor is a different concern, than if there is induced fission going on inside the reactor. You could not have enough fissile material in one place with a moderator around it to produce induced fission outside the reactor. Just the very low level of neutrons detected would preclude that possibility. The level is so low it may be from cosmic rays. These are less frequent the higher the energy. So even if the levels are above the usual cosmic ray background, they may just have measured a particularly energetic event. To confirm actinides outside the reactor they have to measure them. I would suspect the spontaneous fission of Pu-240 as the only likely candidate. Large amounts made during reactor operation and a significant spontaneous fission rate. If they had gamma spectrometers, they could detect the associated gammas with the alpha decay of Pu-240, which is millions of times higher than the Sf rate. If they got close enough they could measure the alpha decay directly. (only a few centimetres in air). Look back for references I`ve made for this.

  244. The latest IAEA report:

    “IAEA Briefing on Fukushima Nuclear Accident (27 March 2011, 13:30 UTC)
    1. Current Situation

    The situation at the Fukushima Daiichi plant remains very serious.

    The restoration of off-site power continues and lighting is now available in the central control rooms of Units 1, 2 and 3. Also, fresh water is now being injected into the Reactor Pressure Vessels (RPVs) of all three Units.

    Radiation measurements in the containment vessels and suppression chambers of Units 1, 2 and 3 continued to decrease. White “smoke” continued to be emitted from Units 1 to 4.

    Pressure in the RPV showed a slight increase at Unit 1 and was stable at Units 2 and 3, possibly indicating that there has been no major breach in the pressure vessels.

    At Unit 1, the temperature measured at the bottom of the RPV fell slightly to 142 °C. At Unit 2, the temperature at the bottom of the RPV fell to 97 °C from 100 °C reported in the Update provided yesterday. Pumping of water from the turbine hall basement to the condenser is in progress with a view to allowing power restoration activities to continue.

    At Unit 3, plans are being made to pump water from the turbine building to the main condenser but the method has not yet been decided. This should reduce the radiation levels in the turbine building and reduce the risk of contamination of workers in the turbine building restoring equipment.

    No notable change has been reported in the condition of Unit 4.

    Water is still being added to the spent fuel pools of Units 1 to 4 and efforts continue to restore normal cooling functions.

    Units 5 and 6 remain in cold shutdown.”

    http://www.iaea.org/newscenter/news/tsunamiupdate01.html
    MODERATOR
    William – you should probably move this up-to-date information to the later up-date Fukushima thread for 26th March. Unfortunately we don’t have the facility to move comments between threads so you will have to cut and paste yourself.

  245. The more I think about it the crazier it seems. The neutron cross-section of Cl-37 is 430 millibarns, which isn’t small, but isn’t large either.

    You’re right, the cross-section is not especially large, and if the Cl-38 were produced by neutron activation of the salt in the seawater by some ongoing fission in the reactor, then I don’t see how it can be there without also seeing Na-24, with half-life of 11 hrs, and probably many other activities from other impurities in the seawater, too.

    To say they’ve got Cl-38 definitively, they need to observe a beta endpoint energy pretty near to the maximum, 4916 keV, as well as the two characteristic Ar-38 gammas at 1642 and 2167 keV, and these in the right relative ratio.

    The activity level they report is very high, in the MBq range, so I imagine if they have a large enough sample of the water then they can definitely see the two gamma energies very well. But I suppose it still may take a little counting to get a firm fix on the beta endpoint, since the beta energy spectrum drops pretty quicky near the max.

    I tried to think of some route, to get either excited Ar-38, or Cl-38 alone, but I can’t come up with anything plausible with single neutrons at thermal fission energies, nothing with any cross-section to speak of: eg the (n,3n) reaction on Ar-40, which is about 1% in air, has a cross-section in the microbarn range. You’ld need 3 GeV protons on U or Pb to get even a few millibarn cross-section for producing Cl-38. And those kinds of energies are out of the question, of course, they’ld have to be from cosmic rays.

    I haven’t seen Cl-38 mentioned in the later analyses of this water, and I notice that they do mention some other isotopes that went away on more careful analysis.

    So I think you’re right, it was likely a case of a measurement error of some kind.
    MODERATOR
    This over night discussion is becoming rambling and threatens to clog up the update thread. Please move it to the Fukushima Open Thread 2.

  246. @Linus
    Basically the same radioisotopes are produced in the fission of Pu and U fission, in somewhat different proportions. Strontium isn’t volitile like Cesium and especially Iodine, so it is harder to mobilize. I would think they would be looking for it though.

  247. @nkinnear

    Ok, I didn’t remember that, but given that, I would still think they would be looking for it in their water samples, given the importance of this isotope in long term hazard analysis. They may have to do some radiochemistry to separate it from all the other radioisotopes, so that would take longer. It is really only through bioaccumulation and ingestion that it would be a real problem, so maybe they are putting off that analysis. It would be interesting to know if it was present, but not that important to know right now. Eventually yes.

  248. To the World, From Fukushima, Japan

    I live in Fukushima-City, Fukushima where is 50 km from Fukushima-Daiichi Nuclear Plant. After the explosion, we have spent One Month and many people, who have no money to escape, have lived with toil and tears. Also, we are very scared because more terrible accident waiting to happen, like Chain Reaction and hydrovolcanic explosion.
    Why we are scared is that TEPCO and the government is not working to help our life and to combat environmental pollution. They are only suppressing information about the situation of the Fukushima-Daiichi Plant. Even the prime minister of Japan, Naoto Kan, say nothing to us. Additionaly, people who lives in Tokyo, capital city of Japan, does not have demonstration against this serious situation, so people living in Fukushima don’t know what to do.
    The environmental pollution effects our jobs since there are endless rumors about radioactivity. if this goes on, we will run out of energy and die.

    Please HELP US.

    Nobuhiro Miyagi

    960-8061 Satsuki-cho, Fukushima-city, Fukushima, Japan.
    nobuclare@gmail.com

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