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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!

 

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

391 replies on “10+ days of crisis at the Fukushima Daiichi nuclear power plant – 22 March 2010”

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

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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.

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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

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> 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:

Click to access BWR_Safety_Design.pdf

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

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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.

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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. ….

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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

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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?

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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…

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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]

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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.

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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.

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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

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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).

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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?

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@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?

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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.

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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

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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.

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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

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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.

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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.

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[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.

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Red_Blue
I OWE YOU AN APOLOGY.
I re-read your original comment and you did include the quotes about no real risk to health.
VERY SORRY – BOWS LOW:)

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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.

Click to access en20110324-2-1.pdf

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

Click to access en20110324-1-1.pdf

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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.

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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

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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?

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@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

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@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.

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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

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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.

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@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.

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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.

Click to access ENGNEWS01_1300968438P.pdf

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@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!

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@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.

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@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.

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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%:

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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.

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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:

Further technical information on Fukushima reactors

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

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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”

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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

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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.

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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

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@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.

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@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.

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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.

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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.

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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?

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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.

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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.

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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.

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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?

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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?

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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.

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@ 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.

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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.

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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.

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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.

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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.

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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

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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.

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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?

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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.

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> 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.

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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.

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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?

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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

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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.

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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

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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

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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”

Click to access 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

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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/

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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

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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??

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> 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. …”

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I posted this earlier but it bears repeating:

“The review of selected accidents which resulted in severe consequences shows that most of them could have been avoided; lack of regulations, contempt for rules, human failure and insufficient training have been identified as frequent initiating parameters.”

Radiation Accidents (J.C. Nénot)
Radiat Prot Dosimetry (1996) 68 (1-2): 111-118.
http://rpd.oxfordjournals.org/content/68/1-2/111.short

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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….”

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