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Fukushima Daiichi Nuclear Accident – 26 March status

This post provides an update to the various situation summaries at Fukushima Daiichi. Please switch to using this post for comments on the latest status reports and news to  hand (the old one is now out of date). For general comments on, use the FD Open Thread #2, and for analysis of the event with respect to future lessons for nuclear power, use this post. Full situation summaries from TEPCO, FEPC and JAIF are given at the bottom of this report.

This is a dramatic before and after photo of the Fukushima Daiichi plant. Click on the image to see more b/a images of the earthquake/tsunami damaged Sendai region (controlled with a swipe tool).

Below is a very brief summary of some key events of the last few days, since the previous status report:

1. There has been concern about salt accumulation in reactor vessels 1-3 (as steam evaporates the injected sea water, the salt is left behind, and if concentrations build to beyond the saturation point, it will begin to deposit and potentially insulate the fuel assemblies). However, NEI now reports the following welcome news:

Fresh water is being injected into the reactor pressure vessel at reactor 3 at Fukushima Daiichi nuclear power plant, Japan’s Nuclear and Industrial Safety Agency said.

TEPCO said that radioactive materials discovered at the reactor 3 turbine building possibly came from water from the reactor system, not the spent fuel pool. TEPCO made that statement after collecting samples of contaminated water in the reactor 3 turbine building and conducting a gamma-emitting nuclide analysis of the sample. The reactor pressure and drywell pressure at reactor 3 remained stable on Friday, leading TEPCO to believe that “the reactor pressure vessel is not seriously damaged.

Cooling efforts at Reactor 1 already had switched back to fresh water cooling. Reactor 2 is still being injected with seawater, but is expected to switch to fresh water soon.

The temperature at the bottom head of the reactor pressure vessels are now 149 C (unit 1), 104 C (unit 2) and 111 C (unit 3) — detailed data in reports below.

2. TEPCO Workers laying cables in the turbine hall of unit 3 stood in ankle-deep stagnant water and their feet were irradiated with beta rays (~180 mSv dose), with shallow burns, after ignoring their dosiometer warnings. They have since been hospitalised. Details in the reports below. 17 personnel have now received doses of >100 mSv, but none >250 mSv — the dose allowed by authorities in the current situation.

3. Water spraying continues on spent fuel ponds 2, 3 and 4, to ensure the uranium fuel rods remain covered. The temperature in unit 2 pool was recently measured at 52 C (see detailed data below).

4. On radiation: levels around the plant perimeter are relatively low and steadily decreasing. Levels of I-131 in drinking water supplies in Tokyo are now below regulated limits and restrictions have been lifted. The IAEA radiation monitoring data, at a distance of 34 to 62 km from Fukushima Daiichi, showed very low levels. To quote:

On 25th March, the IAEA radiation monitoring team made additional measurements at distances from 34 to 62 km from the Fukushima nuclear power plant. At these locations, the dose rate ranged from 0.73 to 8.8 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.07 to 0.96 Megabecquerel per square metre.

5. World Nuclear News provides a new summary: Fukushima Daiichi two weeks on. To quote:

Investigations are now underway into the unexpectedly high level of contamination in the water, particularly as the basement of the turbine building is not a recognised radiation area. One theory is that there is a leak from the reactor circuit, but pressures in the reactor vessel indicate this must be elsewhere in the loop.

Despite this disappointment, steady progress continues to be made on site. Instrumentation is being recovered at units 1, 2 and 4 and lights are on in the control rooms of units 1 and 3. Power connections have reached all the units and checks are underway before normal systems can be re-energised. The shared pond for used fuel pond has now been reconnected.

Here are some interesting photographs from inside the buildings, taken on 23 March by by the Operational Safety Inspector.

6. Geoff Russell (a regular BNC author on food and climate change issues) has a really good piece, reflecting on many of the issues discussed here over the last few weeks. His original title was: Japanese nukes … good news in a bleak landscape.

Some useful technical details are available from NISA Major Parameters 1800 March 25, and the NISA summary conditions report for each reactor (click on the diagram below to access the PDF):

Below is a situation update of the Fukushima Daiichi site, from TEPCO Washington office:

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(1) Result of the investigation on highly radiated workers.

Below are the investigation results of their working environment. Radiation dose rate of surface of the water is approximately 400 mSv/h. Result of gamma-ray nuclide analyses based on sampling of the stagnant water on the basement floor of the turbine building of Unit 1 of Fukushima Dai-ichi Nuclear Power Station. We are assessing radiation dose of 2 worker’s leg skin by beta ray. This incident would be caused because the workers regarded radiation dose of working area as low from survey result of radiation dose on March 23, it was about 0.5 mSv/hr at 5:00 and no major water puddle there. Workers continued working without recognizing change of work environment although their APD were alarming during the work TEPCO has thoroughly instructed its employees and contractor workers to pay attention to the alarm of their APD and evacuate when necessary.

Regarding this event, Fukushima Labor Bureau gave TEPCO verbal instructions. After summerising lessons learned and future measures to this event, TEPCO will report related government ministries and agencies to make sure radiation control thoroughly.

(2) High radiation water may come from the unit 3 reactor, not spent fuel pool.

As for the leakage of radioactive materials at Unit 3 turbine building, we assume the water came from the reactor. We collected sample of the contaminated water in the turbine building of Unit 3 and conducted the gamma-emitting nuclide analysis. We confirmed the following nuclides with short half-life.

Nuclides              half-life (days)     density (bq/cubic centimeter)

Iodine 131              8.06                              1.2 x 10E6

Cesium 136          13.16                             2.3 x 10E4

Barium 140            12.75                            5.2 x 10E4

There are 148 fuel rods with less than one year of cooling period in the spent fuel pool at Unit 3. Those fuel rods were transferred to the spent fuel pool between Jun 23 and 28, 2010 having had more than 200 days of cooling period. Nuclides with short half-life had sufficient time for decay in the spent fuel pool, so it seems possible that the contaminated water in the turbine building is from the reactor.

We do not deny possibility that there might be certain damage to the reactor of Unit 3. Even should that be the case, as plant parameters such as the reactor pressure and D/W pressure is stable , we presume that RPV is not seriously damaged.

We are injecting seawater and from the night of March 25, fresh water into the reactor. The water turns into steam and comes out from the reactor vessel through the SRV, then depressurized at the suppression chamber and condensed to water. This flow of water is cooling the reactor. Having experienced fluctuations of temperature and pressure, the containment function might be loosened somewhere. In any event, the above is a possibility, not yet confirmed.

(3) Water injection into the pools and the reactors.

Unit 1: Sea water injection into the reactor pressure vessel, from 3:37 pm on March 25th, we have started to inject fresh water into it.

Unit 2: From 10:30 am on March 25th, seawater injection through Fuel Pool Cooling and Filtering System (FPC) was started. This finished at 0:19 pm.

Unit 3 From 5:35 am on March 24th, seawater injection through Fuel Pool Cooling and Filtering System (FPC) was started and finished at 4:05 pm.

Spraying at the spent fuel pool by Kawasaki City Fire Department was carried out from 1:28 pm to 4:00 pm on March 25th.

Unit 4: From 2:35 pm on March 24th, spraying water by the concrete pumping vehicle was conducted and ended at approximately 5:30 pm on the same day.

From 6:05 am on March 25th, seawater injection through Fuel Pool Cooling and Filtering System (FPC) was started and finished at 10:20 am.

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Here is the latest FEPC status report:

  • Radiation Levels
    • At 7:00PM (JST) on March 25, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 199.5 micro Sv/hour.
    • Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on March 25 are shown in the attached PDF file. English version is available at:    http://www.mext.go.jp/english/radioactivity_level/detail/1303962.htm
    • 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 11:00AM on March 25, activities for the injection of freshwater in place of seawater into the reactor core started and at 3:37PM, the injection of freshwater into the reactor core started.
    • At 2:00PM on March 25, pressure inside the reactor core: 0.342MPa.
    • At 2:00PM on March 25, water level inside the reactor core: 1.65 meters below the top of the fuel rods.
    • At 2:00PM on March 25, pressure inside the primary containment vessel: 0.280MPaabs.
  • Fukushima Daiichi Unit 2 reactor
    • At 10:00AM on March 25, the temperature of the spent fuel pool: 82.4 degrees Fahrenheit.
    • At 10:30AM on March25,　TEPCO began to inject seawater into the spent fuel pool via cooling and purification line, until at 12:19PM (approximately 38 tons in total).
    • At 11:00AM on March 25, activities for the injection of freshwater in place of seawater into the reactor core started.
    • At 2:00PM on March 25, pressure inside the reactor core: -0.016MPa.
    • At 2:00PM on March 25, water level inside the reactor core: 1.4 meters below the top of the fuel rods.
    • At 2:00PM on March 25, pressure inside the primary containment vessel: 0.12MPaabs.
    • As of 7:00PM on March 25, approximately 96 tons of water in total has been injected into the spent fuel storage pool.
    • As of 7:00PM on March 25, external power generation is connected and the functionality of the electric devices is being checked.
    • As of 7:30PM on March 25, the injection of seawater into the reactor core continues.
  • Fukushima Daiichi Unit 3 reactor
    • At 11:00AM on March 25, activities for the injection of freshwater in place of seawater into the reactor core started and at 6:02PM, the injection of freshwater into the reactor core started.
    • At 1:28PM on March 25, Kawasaki City Fire Department began to shoot water aimed at the spent fuel pool until 4:00PM (approximately 450 tons in total).
    • At 2:00PM on March 25, pressure inside the reactor core: 0.038MPa.
    • At 2:00PM on March 25, pressure inside the primary containment vessel: 0.1089MPaabs.
    • At 2:10PM on March 25, water level inside the reactor core: 1.9 meters below the top of the fuel rods.
    • As of 7:00PM on March 25, approximately 4,497 tons of water in total has been shot to the spent fuel storage pool.
  • Fukushima Daiichi Unit 4 reactor
    • At 6:05AM on March25, TEPCO began to inject seawater into the spent fuel pool via cooling and purification line, until at 10:20APM.
    • At 7:05PM on March 25, TEPCO began to shoot water aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete.
    • As of 7:00PM on March 25, approximately 685 tons of water in total has been shot to the spent fuel storage pool.
    • As of 7:00PM on March 25, external power generation is connected and the functionality of the electric devices is being checked.
  • Fukushima Daiichi Unit 5 reactor
    • At 3:00PM on March 25, the temperature of the spent fuel pool: 98.4 degrees Fahrenheit.
    • At 3:00PM on March 25, the temperature of the water in the reactor core: 129.0 degrees Fahrenheit.
  • Fukushima Daiichi Unit 6 reactor
    • At 3:00PM on March 25, the temperature of the spent fuel pool: 69.8 degrees Fahrenheit.
  • Fukushima Daiichi Common Spent Fuel Pool
    • As of 7:00PM on March 25, approximately 130 tons of water in total has been injected to the spent fuel storage pool.

——————————

Finally, the latest Japan Atomic Industrial Forum summary table (21:00 March 25):

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.

259 replies on “Fukushima Daiichi Nuclear Accident – 26 March status”

Really good report, Barry.
But I’m missing your points about the reports, you should put it, they were very useful.

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Why not just concrete the whole thing? Can anyone confirm the following comment (found on http://www.facebook.com/note.php?created&&note_id=204623026234158&id=96699782061 ),
“Unfortunately, you can’t entomb live/melting reactors—-they would have to explode/burn off a large amount of material before they could bury the rest without a criticality. For example, clean up crews at Chernobyl stated at least 70% of it’s reactor had vaporized before entombment(contrary to official reports).”

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sidd,
Forget about Cs138. Cs137 has a 30 year half life and is therefore quite useful for calibrating area monitors.

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The Main Stream Media in the USA has been “Having a Cow” over the workers exposed to radioactive water who were sent to hospitals.

I am much relieved to hear that their dose was ~180 mSv of Beta radiation (hence not a deep dose). Such a dose might produce symptoms similar to what I got from UV exposure last week but is orders of magnitude short of being life threatening as the MSM wants us to believe.

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Best case, when will they stop venting radionuclides directly to the environment? [deleted un-supported personal opinion. Re-submit with refs/links.]
–bks

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Guy Jean, the Facebook link is now obsolete.

Concreting the whole thing would be a very bad idea:

1) It would prevent any sort of cooling. The casing would most likely crack and leak

2) It would prevent all investigations, lesson-learning and dismantling

3) The resulting “monument” would be a major emotional landmark for the anti-nuke community

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bks, your question is interesting from two perspectives.

Firstly, a best case answer is not really going to be much use for any real world problem. The best case answer to the question “what will happen if I run a red light” is “nothing”. The worst case involves collisions, possible hazardous material leaks, fires, deaths, court action, financial loss and prison time.

So, the best case is some kind of continuing reduction, as each source is diagnosed and halted. How long is a piece of string?

The second issue I have with the question is the lack of consideration of effects.

Parallel questions could be:
“What are the probable health effects due to known releases thus far?”, or
“How much of (name one or more radionuclides) has been emitted so far to (air/water/soil) (on/off) site?”, or
“How long is it estimated that known pollutants from (power station/ tsunami/ other cause) continue to pose a health threat at the boundary of the power station site?

The answers to these questions will quite likely be sought by those why seek to return to the devastated regions, up and down the east coast of Japan. The answer to the question you posed will not help people facing this type of quandary.

Come to think of it, I wonder whether known releases, radioactive or otherwise, could be expected to cause adverse health effects beyond the site perimeter. Or 10km distant and, if so, whether this is likely to still be the case in 1 month? 1 year?

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sidd, neutron irradiation of salt that produced Cl-38 would also produce Na-24, which isn’t mentioned. So I don’t think this is the answer. Perhaps more information will become available over the weekend.

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John, I haven’t seen any radiation / radionuclide detection numbers that would cause adverse health effects at the plant perimeter, or further afield. Based on total likely exposure, that is, rather than briefly elevated rates.

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Thanks, Joffan. My thoughts entirely. There was a hint of exceedance of allowable limits but with probable zero health effects re the outfall canal, but it appeared to me that the I131 would quickly decay and the other two species reported would simply and quickly be diluted to below detectable levels, provided of course that the emissions ceased.

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That Geoff Russell article you’re recommending is excellent!

The question I’m asking any media contacts I have is why were they not providing “balance” by reporting at least some part of this perspective instead of what we all saw? I remind them of their decades of insisting on providing “balance” by publishing the views of the climate science deniers all this time and even now.

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Following the arguments of Prof Wade Allison based on the evidence of H&N data and on medical therapy techniques, I am persuaded there is no increased cancer risk from radiation exposure to anyone unless they suffer a dose of at least 100mSv in a period of less than one month.

So right now there might be a few of the workers who face an increase of a fraction of a percent in their cancer risk. No-one else.

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Yes,the Geoff Russell article in The Punch was quite useful.

But of course he just had to squeeze in a bit of the vegan propaganda.

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Barry, as usual, a very informative factual summary.

I thought Geoff Russell’s piece was masterful and am quite prepared to accept his statistics relating to meat eating, despite being a carnivore myself and despite having made my living in the field of farm animal husbandry. Podargus sniffs out vegan propaganda, but I hope that his statement doesn’t imply that he thinks that Geoff is actually telling lies over the meat-associated bowel cancer statistics.

If one new case of bowel cancer in Australia is diagnosed per 1000 head of population and most diagnoses are made in people aged over 65, this knowledge wouldn’t stop me eating meat. We all need to die of something specific now that doctors don’t accept that old age itself is a sufficient reason. Dementia and strokes and their associated mental or physical protracted decay are more alarming prospects for most.

It has been suggested here previously that a worst case nuclear accident could lead to as many as 50000 extra deaths, presumably spread over a 30 year period. If my grasp of the facts is reasonably correct, this represents less than one tenth of those associated with bowel cancer in Australia. A Chernobyl-type accident in Australia (which DV82XL deemed to be worst case for all practical purposes) and which probably, at most, was responsible for 5000 extra deaths (discounting unnecessary -with hindsight- abortions) would have less than 1% of the bowel cancer effect while a Fukushima event would have none.

At present, radiophobia rules. It seems that, until Radiation Protection Boards are prepared to re-evaluate their standards, based as they currently are on LNT theory and a huge margin of “safety”, in the light of post Chernobyl studies, radiophobia will continue to remain powerful.

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Question: Salts diisolved in sea water will obviously concentrate in the reactor core, as steam is produced and vented to the suppression pool. The main effect of moving from seawater injection to freshwater injection would seem to be that the salinity of the water in the core will stabilize rather than increase. Is there anything else? How salty are the cores at present? Are there any advantages to seawater injection (besides the availability of supply)?

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Question: What is the path of water delivered for cooling to the spent fuel ponds and to the reactors, once it leaves those sites?

Some fraction is vented as steam, which then condenses or drifts offsite.

Presumably, most of it flows into drainage pipes, perhaps after making its way into the basement. From there, the pipes likely empty into the sea.

Or is much of the water soaking into the ground underneath and beside the buildings’ foundations?

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fyi (I’d posted this on other threads, not realizing this one was here at the time, so just an fyi)

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)

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@Guy Jean, on 26 March 2011 at 3:04 PM

Even if entombed in concrete, I believe re-criticality would be extremely unlikely, and perhaps almost impossible. Criticality requires a certain geometry – and the water acts as a moderator to help reflect neutrons back into the fuel to promote criticality. As you lose geometry and water, you lose the likelyhood of criticality also. Besides, it would be difficult to entomb themm, and far better to bring these reactors under control if possible so we can learn from what happened.

Also – Chernobyl can’t even be compared to these reactors – it was a vastly different design. It had a massive explosion in the core itself, and for all intents and purposes no containment building or vessel. Part of the core was vaporized in the explosion, and rather than water as a moderator, it primarily used graphite, which was set on fire by the explosion – all of this spread contamination (and actual chunks and bits of fuel!) around the site, and served to pump a large amount of radiation up high into the atmosphere.

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@gallopingcamel, on 26 March 2011 at 3:56 PM

Galloping, I might be wrong, but as best I understand it, the dosimeters on their chests probably read 170-180 mSv. Not enough to cause any symptoms or likely even any increased risk of cancer. Meanwhile, they were apparently standing in that water for just under an hour – and the water read 400 mSv/hr. Which implies a dose to the feet/lower legs of a little less than 400 mSv. Obviously that’s a LOT higher than the 170 mSv, but I don’t think there would be any problems expected from it.

It seems that skin erethema (reddening) probably doesn’t occur before about 6 Sv (6000 mSv – some sources say as ow as 2 Sv), and skin burns probably don’t occur until closer to 20 Sv (20000 mSv). So this sounds to me that there is a good chance they don’t wind up with any symptoms – if the reported dose rate of that water was 400 mSv/hr (and was beta + gamma, not just gamma), and there weren’t significantly hotter spots in the water. In other words, I’m still just speculating based on the info available, but from that, it does sound promising. Let’s keep our fingers crossed!

We were speculating on this issue also over on the 10+ day thread, and I posted a little info on skin effects there if you are interested. https://bravenewclimate.com/2011/03/23/fukushima-10-days-crisis-22-march/

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re post by: John Bennetts, on 26 March 2011 at 4:44 PM said:

Come to think of it, I wonder whether known releases, radioactive or otherwise, could be expected to cause adverse health effects beyond the site perimeter. Or 10km distant and, if so, whether this is likely to still be the case in 1 month? 1 year?

John, for whatever it’s worth – I have no idea if the rad releases to date (or even if one exrapolated reasonably for another week or two into the future) would add up to anything significant.

What I am sure of, however, is that they’ll be running the numbers for lifetime worst case total pathway exposures before long, if they aren’t already. Not just short term, but calculations that take into account every mode of exposure that could possibly contribute (plume, cloud shine, ground shine, ingestion, etc), for each radionuclide that has been detected, based on as many of the various samples that have been taken at all the different distances, and for each age group (infant, children, adults, pregnant women). That gets projected to what total lifetime would result, and which group is the limiting group (e.g., highest total dose rate or most susceptible – virtually always winds up being infant/cow/milk as the limiting pathway).

Anyhow, point is that they’ll almost certainly calculate it out not just for a month or a year, but for lifetime ‘worst case’ doses – and that includes assumptions such as the person was standing outside the entire time, drinking and eating only the most contaminated foodstuff/liquid, and so on.

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@rationaldebate
The workers did get a skin erethema in fact the National Institute of Radiological Sciences, where they received specialized treatment, said the two were exposed to 2 to 6 sieverts of radiation below their ankles

You may argue that’s just a alpha radiation with effects localized to skin only

gallopingcame was referring to beta radiation only

www3.nhk.or.jp/daily/english/26_03.html
http://english.kyodonews.jp/news/2011/03/81122.html

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amac78, on 26 March 2011 at 8:15 PM said
“… is much of the water soaking into the ground underneath and beside the buildings’ foundations?”

The flow rates required for cooling are of the order of hundreds of tonnes per day. Seepage into the foundations, assuming that a pathway exists, is likely to be at least two orders of magnitude lower than the cooling water flow; probably even less. Remember that seepage so close to the shoreline probably relies on discharge to the ocean, so there is little practical difference between discharge via drains and seepage via groundwater paths.

Essentially, it appears to be a fair bet that if cooling water finds its way out of containment, it will exit via the outfall canal. Indeed, announcements today suggest that, in order to minimise radiation levels, this may be intentional.

NB: Conjecture on my part is based on the statement “TEPCO took immediate action to drain off this water since current situation would cause delay in recovery work. (11:35, March 26)”, cited above.

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John Bennetts, thanks for the response to my query.

> The flow rates required for cooling are of the order of hundreds of tonnes per day.

My understanding is that “bleed [steam] and feed [sea/fresh water]” is still the main strategy for cooling the cores. It seems unlikely to me that you mean that hundreds of tonnes of water are being bled off each day as steam.

[I suspect this has been covered in a prior thread, thus, apologies. Hard for a lay person to keep things straight.]

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amac78:

I may have this wrong, so take care.

My recollection is that waste heat at the condenser is disposed of via cooling water, to the outfall canal. The flow rates for this would be very high indeed – thousands of litres per second for a 6-unit station.

I was factoring back to get a rough guesstimate (ie rougher than a normal guesstimate), and with one eye on the apparent water flows via fire trucks, water bombing and so forth. Hence hundreds of tonnes per day, probably per unit, but that will provide an indication.

My main point was that that the water table would be quite high, owing to proximity to the ocean. Thus, additional water entering the foundations will have to be almost immediately discharged and there is really only one way out – the ocean.

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And more:
Hopefully, cooling water losses via steam will cease pretty soon, as things cool to below 100C. Figures provided at the top of this thread seem to indicate that most, if not all, cores are below 212F/100C and typical unit cooling water flows are in the range of 100 – 200 tonnes per day.

So… water in and water out. Not much steam any more.

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re post by Monica, on 26 March 2011 at 9:55 PM said:

@rationaldebate
The workers did get a skin erethema in fact the National Institute of Radiological Sciences, where they received specialized treatment, said the two were exposed to 2 to 6 sieverts of radiation below their ankles. You may argue that’s just a alpha radiation with effects localized to skin only

gallopingcame was referring to beta radiation only
www3.nhk.or.jp/daily/english/26_03.html
http://english.kyodonews.jp/news/2011/03/81122.html

Hi Monica,
The various reports out there vary widely in terms of what they report on this incident, including the 2-6 Sv you note, and that they actually HAVE burns – all the way down to just that they were decontaminated and sent to the hospital in case they had beta burns.

alpha particles are stopped by the dead layer of your skin – they wouldn’t have alpha burns or erethema. It takes beta or gamma to cause that. The 2-6 Sv seems to have only shown up in one or two reports, with the majority indicating a much lower likely dose – and the 2-6 doesn’t match well with the reported surface dose rate of the water either. It is also a huge range for a supposedly suspected dose. It does, however, conveniently happen to match the lowest dose at which beta burns might occur (although a number of sources would say it takes more on the order of 20 Sv for burns). This makes me suspicious that translation difficulties or misunderstanding led to the few reports of this as the supposed actual exposure, when what was meant was that’s the dose at which beta burns might occur.

Obviously I don’t KNOW that – but the point is that it is anything but clear at this point, and that high dose doesn’t seem to match the other reported facts or the majority of reports.

I’m not sure where you get that GallopingCamel was referring to a beta dose with the 170 mSv either. That’s not been reported anywhere and it wasn’t in the linked report you gave either. The most likely source of that reading is the dosimeters that they were wearing, and that would be either gamma, or gamma + beta.

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I wonder what the total number of 6+ aftershocks the plant has seen? If there were any 7+ magnitude aftershocks? (on the Moment Magnitude or Richter scale that is, not meaning the Japanese scale – because I’d like to be able to know using the same basic scale as the primary 8.9 or 9.0 EQ was reported on)

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@Monica – just an example of why I say reporting on the dose to the worker’s legs is “all over the map” – World Nuclear News’ report:

Three contractors were installing cables in the first floor and 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.

http://www.world-nuclear-news.org/RS_Exposures_and_progress_at_Fukushima_Daiichi_240311.html

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(ops moderator I will report my comment with the right names..)

@rational debate

gallopingcamel’s comment was, I quote
“I am much relieved to hear that their dose was ~180 mSv of Beta radiation”
I don’t know what his source his, I was just pointing out he made a specific reference to beta, since your initial reply was to him

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http://www.smh.com.au/world/more-damage-revealed-at-fukushima-20110326-1cazz.html

“Tokyo
March 27, 2011

NEW signs have emerged that parts of the crippled Fukushima Daiichi nuclear plant are so damaged and contaminated that it will be even harder to bring the plant under control soon.

At the same time, Japanese officials began encouraging people to evacuate a larger band of territory around the complex.

Radiation levels in seawater inside the quake-damaged reactors may be rising, Japan’s nuclear watchdog said yesterday. Speaking to a national audience at a news conference on Friday night, two weeks after the magnitude 9.0 earthquake and the devastating tsunami that followed it, Prime Minister Naoto Kan dodged a reporter’s question about whether the government was ordering a full evacuation, saying officials were simply following the recommendation of the Japan Nuclear Safety Commission.

Authorities said that they would now assist people who want to leave the area from 20 to 30 kilometres outside the plant, and that they were now encouraging ”voluntary evacuation” from the area. “

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Monica/Rational Debate,
The 170 mSv to the skin is way too low of a skin dose equivalent to cause erythema. Transient erythema, minor skin reddening, has a threshold in the range of 1-2 Sv. Remember, this is shallow dose equivalent, or dose to the skin, not to be confused with whole body, or deep dose. So at 0.4 Sv/h surface dose rate of the water, they could have received a dose capable of transient erythema in 2-3 hours. As Rational points out, this dose is not from alphas, which cannot irradiate the living cells of the skin when in contact with the skin surface due to 100% absorption in the dead skin cells. As for health impacts off-site, there are no data anywhere that support any increase cancer in persons receiving less than 0.1-0.2 Sv to the whole body. Based on levels reported, it is highly unlikely that this dose range will be reached among members of the public. So any increased ‘risk’ of cancer will be based on extrapolations based on the LNT modes. Purely hypothetical. The more likely outcome is no adverse health effects.

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Wait:
> John Bennetts, on 26 March 2011 at 10:34 PM said: “Figures provided at the top of this thread seem to indicate that most, if not all, cores are below 212F/100C”

What’s your source for this belief?

The figures at the top of the thread say:

“temperature at the bottom head of the reactor pressure vessels are now 149 C (unit 1), 104 C (unit 2) and 111 C (unit 3) …”

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Joffan, appealing to the xkcd chart, damage to health to a population will occur at 10 microsieverts/hour for one year (87 millisieverts) so I do not understand your comments above, as the readings at the perimeter are 20 times that level, and stations 32 and 33 (MEXT data) 30 km away are at 3 to 10 times that level.

Plus we do not have data for the period following the major releases after the hydrogen explosions.

–bks

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@Hank:
You are correct. My apologies.

Unit 5 is the only one reported to have core temp below boiling. Unit 6, I suspect, is also cool.

In my haste, I confused rod pool temps and core temps.

So, while core temps are trending downwards, Units 1 to 3 are still just above 100C.

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> core … below boiling

These are pressure vessels under pressure; boiling would be rather higher than 100C.

The bottom head is not the core; the bottom head is the base of the pressure vessel.

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I don’t mean to nitpick, it makes a big difference which core (which kind of fuel) and which openings are being used to pump water in and take water and steam out of each reactor — and what the temperature of the return water is. If they’re flooding sea water through and letting the overflow back into the ocean, that’s very different than if they’re circulating water and steam through the cooling torus or the turbine loop, maybe filtering crap out of it, and returning that still relatively warm water to the reactor. Details matter enormously. If anyone has them, pointer welcome.

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Hank Roberts, on 27 March 2011 at 12:04 AM said:

>>At the same time, Japanese officials began >>encouraging people to evacuate a larger band of >>territory around the complex.

Monitoring post 83 at the 20 km boundary to the Northwest is at 82 microSieverts and at monitoring post 82 at 30 km to the Northwest is at 49 microSieverts. A few km either side and the levels drop into the single digits.

So there are some hotspots with radiation levels about 1/4 of what the levels are at the plant boundary out to 30km.

Click to access 1304318_2619.pdf

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Hank Roberts, on 27 March 2011 at 1:15 AM said:

> core … below boiling

These are pressure vessels under pressure; boiling would be rather higher than 100C.

The bottom head is not the core; the bottom head is the base of the pressure vessel.

—

Has anyone seen actual pressure readings? The official Japanese charts I’ve seen merely state the pressure as “stable” or “rising” or “lowering”. None of these charts gives us any indication of actual pressure reading, therefor actual boiling points for the coolant. I know from designing race car engines that coolant pressure greatly impacts the boiling point and cooling system. I can only imagine the impact on a nuclear reactor cooling system. Can any of you experts be sure that they have the pressure required to keep the coolant from boiling at this or that stated temp? It seems you are missing a key element – actual system pressure. Another thought that comes to mind is, if the coolant is boiling would that constant expansion of the boiling water keep pressures erroneously stable despite the constant slow leaking of coolant (if such a leak is present).

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We must be skeptical of all information that Tepco is feeding the government agencies, both statistical, and operational. They seem to have a pattern of secrecy and misconduct developing that is anything but trustworthy.

—–

Government spokesman Yukio Edano urged Tokyo Electric Power Co. to be more transparent, two days after two workers at the tsunami-damaged Fukushima Dai-ichi plant suffered skin burns when they stepped in water that was 10,000 times more radioactive than levels normally found near the reactors.

“We strongly urge TEPCO to provide information to the government more promptly,” Edano said.

The Nuclear and Industrial Safety Agency, or NISA, said TEPCO was aware there was high radiation in the air at one of the plant’s six units several days before the accident. And the two workers injured were wearing boots that only came up to their ankles — hardly high enough to protect their legs, agency spokesman Hidehiko Nishiyama said.

“Regardless of whether there was an awareness of high radioactivity in the stagnant water, there were problems in the way work was conducted,” Nishiyama said.

NISA warned TEPCO to improve and ensure workers’ safety, and TEPCO has taken measures to that effect, Nishiyama said, without elaborating.

TEPCO spokesman Hajime Motojuku declined to comment.

http://www.ajc.com/business/japans-government-criticizes-nuke-886410.html

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Has anyone seen actual pressure readings?

NISA, IAEA and JAIF all report the actual pressures, but since the gauge pressures of reactors 2 and 3 read negative values (under atmospheric pressure), these are consider unreliable.

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As I understand it: at the present time, the cores of units 1, 2, and 3 are somewhat above 100C, and under pressure (thus, not boiling).

Decay is continuing in the fuel rods, at much lower levels than on March 11th, and at levels that decrease slightly each day. Still, that’s enough to generate some megawatts worth of heat, per reactor core.

“Stability” means this excess heat is removed at about the same rate that it is produced.

This removal can be through —

(1) bleeding off water (flashes to steam) and sending it to the torus — as long as there’s a way to cool the torus

(2) bleeding off water (flashes to steam) and venting it, so that it condenses onsite or disperses. This requires injection of water (sea or fresh) to make up for what’s lost.

(3) pumping core water through a circuit that includes a heat-exchanger, as long as there’s fluid to be cooled (e.g. seawater).

(4) leaking of core water into the building housing the reactor (as long as it is drained, and as long as the core is replenished by injection of replacement water).

(5) black body radiation (unlikely to account for much heat).

As far as I know, AC pumps haven’t yet been started.

What is the major pathway for removal of heat from the fuelled cores, at present?

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Mr. Shelby writes:
“Has anyone seen actual pressure readings? ”

Please see http://www.jaif.or.jp/english/index.php where periodic status reports may be found. In particular, on the 26th

Daichi

Reactor 1:

Water level
26th 09:30: (A) -1650mm (B) -1600mm

Reactor pressure
26th 05:00 (A) 0.353MPaG, (B) 0.360MPaG
26th 09:30 (A) 0.376MPaG, (B) 0.360MPaG

CV pressure
26th 05:00 0.270MPaabs
26th 09:30 0.270MPaabs

Reactor 2

Water level
-1100mm

Reactor Pressure
26th 10:40 A)-0.014MPaG B)-0.016MpaG

CV Pressure
26th 10:40 0.115MPaabs

Reactor 3

Water Level
26th 10:00 A) -1800mm, B) -2300mm

Reactor Pressure
26th 10:00 A)0.038MPaG B)-0.101MPaG

CV Pressure
26th 1000 0.1066MPaabs

Please do thech the previous reports, but if If I recall correctly,:

Reactor 1 has been holding pressure, water levels have been recently rising.

Reactor 2 pressure and CV pressures have been roughly at atmosphere for a while, water levels rising.

Reactor 3 had a pressure excursion, and has now returned to atmospheric, water levels very low, cannot seem to be raised.

sidd

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Joffan wrote:

John, I haven’t seen any radiation / radionuclide detection numbers that would cause adverse health effects at the plant perimeter, or further afield. Based on total likely exposure, that is, rather than briefly elevated rates.

Tap water samples in Litate (40 km from plant): 965 bq/kg Iodine-131 (three times the government safety limit, nine times the limit for infants).

Soil samples in Litate: 163,000 bq/kg Cs-137 (1,630 times the normal level). “Based on a rough estimate, a person standing on soil with 163,000 Bq/kg of cesium-137 would receive about 150 millisieverts per year of radiation … well above US EPA standard of 50 millisieverts per year.”

There are four towns located within 20 km “hard” evacuation zone: Namie, Futaba, Okuma, Naraha (and sampling has been minimal in these locations). While it’s still too early to tell, concerns and risks abound for many residents in these regions: “‘We’ve heard that it could be years, maybe even tens of years before we are allowed back,’ Imura says. ‘It’s possible that Namie will cease to exist.'”

Keep in mind too … radiation has been blowing offshore (away from land) for much of this time period. The radiation risk from this accident could have been far worse (and we still have high levels and little control over the situation). The damaged fuel in the reactors could take months to years to cool. We have a good guess of contamination levels in coolant water at the power plants, and much of this is heading right back to the ocean.

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right, EL, the radiation “could” have been worst, the core “could” have melted, the whole plant “could” have been destroyed. anything, or quite anything, could have happened, from smallpox to asteroid rain.
but actually the core did not melt, the winds did not blow to land, the plane is still there, reasonably stable and cooling slowly.
the problem (a very big one, as far as I can think) is quite ALL that actually *happened* outside the nuclear plant (devastation, pollution, death, plague, power shortages, orphans, chemical waste spread everywhere, starvation, cold, ravaged nature and landscape, count it if you can) looks as it was happened in other planet, or in a very remote time.
of course, this is a discussion focused only on Fukushima accident and its aftermath, but just giving a look to the average media one can see that the only news from Japan are about the reactor, and grossly inaccurate news indeed (this morning the italian TV news were blabbering about a “really serious situation in Fukushima, quite out of control, with an increasing count of exxxxtreme dangerous radiation”….).

good luck that Libyan war started, otherwise the level of media BS would reach unprecedented records….

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bks, please note that these reported rates will not be sustained for a year. Or even a month. And note my other observation, due to Prof Allison; that from the known recovery rates of patients undergoing radiotherapy, the human body recovers from subcritical radiation damage within a month (more probably two weeks) and none of these integrated rates will deliver 100mSv within a month.

“Integrated” here does not mean “take the highest rate and multiply it by the number of hours in a month”, either. Worst-case thinking may be interesting for eliminating scenarios but it does not model reality.

I can phrase it another way: why do you choose to extrapolate a year’s worth of values? Why a year? Why worst-case all the hours of that year?

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EL – first, thanks for the links. Don’t you just wish some of these stories gave us onward links so we could look at (say) the values for soil samples they took at all six locations?

On iodine-131 in tap water: call me back when the levels have stayed that high for a week. On towns in the evacuation zone: people’s speculations and fears are not evidence for actual radiation health effects. On 150mSv pey year: = 12mSv per month; no health effect (p46).

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Joffan, xkcd and all U.S. agencies talk about yearly doses as does the nuclear industry. I am quite aware that the effects of dosage is statistical and time-dependent. But I would bet my car that Berkeley is not the *worst case*. It’s just the only place that’s doing the monitoring correctly. What we should be looking at is data like this from Sendai and Tokyo. Then we could talk intelligently. You go to science with the data you have, not the data you wish you have.

Also, how do you know what the future holds?

–bks
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This is an update thread – your conversation is on the wrong thread – please move to Open Thread or Preliminary Lessons from Fukushima.learned.

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[…] Fukushima Daiichi Nuclear Accident – 26 March status (via BraveNewClimate) Published March 27, 2011 Uncategorized Leave a Comment This post provides an update to the various situation summaries at Fukushima Daiichi. Please switch to using this post for comments on the latest status reports and news to  hand (the old one is now out of date). For general comments on, use the FD Open Thread, and for analysis of the event with respect to future lessons for nuclear power, use this post. Full situation summaries from TEPCO, FEPC and JAIF are given at the bottom of this report. Th … Read More […]

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@EL, on 27 March 2011 at 5:55 AM said:

>>Soil samples in Litate:

We know that US DOE did high resolution aerial radiation measurement and turned it over to the Japanese Government.

http://blog.energy.gov/content/situation-japan

We can speculate that the Japanese Officials are either randomly sampling according to a grid pattern or they are using the high resolution aerial surveys to pinpoint potential problem areas.

The fact that they have 5 sampling points to the northwest that are maybe 1 km apart leads me to ‘suspect’ they are pinpointing.

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Joffan wrote:

EL – first, thanks for the links. Don’t you just wish some of these stories gave us onward links so we could look at (say) the values for soil samples they took at all six locations?

What makes you think they aren’t providing these sample results:

Click to access 1304097_2410.pdf

There is some really incredible research on radiation sampling from IAEA, US, French groups, NGOs, health and science ministries, oceanographers, sanitation and municipal government agencies, food safety, and other local health authorities on the ground (and in the water) in Japan. It’s probably one of the more pressing issues going on at the moment (beyond controlling the situation at the power plants). We have sustained readings for this area of 105 – 170 microsieverts over the last five days. Most of this quadrant of Japan will be an active research zone for some time, and will be gone over with a fine tooth comb as accident investigations proceed and scientists descend on what is likely to be viewed as one of the great radiological experiments of the 21st century (even though we are only a decade in). Arguing that people aren’t doing the work, or are biased in selectively sampling only highly contaminated areas is absurd.

The latest DOE data from overflights shows directionality for many of these plumes over land, and this is what we are seeing on the ground at most local sampling results. Radiation doesn’t just sit in one place either, I’m pretty sure you know this. It decays into different constituents, and it travels up and down the food chain and bio-accumulates in the environment. You can point to individual sample readings and say gamma readings will be negligible over time (and you’d be correct). But there are many other ways that less penetrating, long lived (300 years) and high energy ionizing particles can get into your body, and pose additional risks to public health (large and small). For a country that gets most of its nutritional needs from the ocean and from crops grown on land, dispersing highly radioactive water into the ocean, failing to contain dangerous radioactive gases carried on the wind, and having four broken down reactors sitting on the beach for a period of years (if not decades) doesn’t sound like something to minimize (or otherwise disregard). With respect to radiation impacts to the environment, we are far more likely be at the beginning of this unfolding drama rather than the end. And if it proves to be inconsequential, I will be the first to visit Fukushima for the delectable farm fresh produce, and depart out of Noda (when the re-build) for the daily catch.
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This thread is for updates on the situation at Fukushima. Please move this conversation to Open Thread or Preliminary lessons learned for Fukushima.
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Issues raised by EL.

At 5:55am this morning, EL stated “Soil samples in Litate: … “Based on a rough estimate, a person standing on soil with 163,000 Bq/kg of cesium-137 would receive about 150 millisieverts per year of radiation … well above US EPA standard of 50 millisieverts per year”.”

I am not familiar with the specific guideline to which EL refers, or why he has selected an annualised dose rate rather than something closer to days or, perhaps, weeks. By so doing, EL has embedded an implicit assumption that, once the emissions have ceased, the radiation levels will not decay with time. This appears to be excessively conservative, or alarmist.

One comparison is the USEPA 4-day limit quoted by US DOE at http://blog.energy.gov/content/situation-japan above. The 4-day limit is 1000 mRem before public health actions are warranted; ie 10mS/day, if my maths are correct.

The 365 day rate quoted by EL works out at 0.5 mS/d; ie one twentieth of the USEPA trigger level.

Further. Prof Alison Wade, in the slide show also cited above by Joffan and found at http://www.physics.ox.ac.uk/nuclearsafety/webpptMay07.pdf provides cogent analysis indicating that exposure of “…100mS gives no increased risk of cancer death over 40 years…”.

This equates to about ten days’ exposure at the rates presented by EL, which are themselves selected from a report which includes a range of readings fors and times. It is perhaps reasonable to assume that nobody will sit at the worst location for 10 days, without spending at least some of their time in other, less radiated, locations.

For these reasons, I conclude that EL’s contribution is a worst case interpretation and an unreasonable extrapolation over time (a year) of data which represents only a point in time.

This has the result of presenting as dangerous and requiring a public health response, as situation which is not outside the relevant EPA guidelines and which is not so high as to warrant a community health response.

This type of exaggeration of the actual risks is unfortunate ecause it delays actions which will lead to rebuilding of communities and relationships, which instill fear and even panic in the population at large, which cause increased but useless expense to the community via excessive responses and, eventually, do actual harm to those Japanese citizens who are most in need of good, realistic advice, emotional support and physical assistance to get their lives back in order.

Scaremongering actually adds to their pain, no matter how well intentioned or mistaken.
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THIS SUBJECT IS OFF TOPIC . WARNINGS OF DELETION HAVE BEEN GIVEN IF THE TOPIC IS NOT MOVED TO Open Thread or Preliminary lessons learned… Prefer Open Thread.

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EL, on 27 March 2011 at 9:45 AM said:

>> Arguing that people aren’t doing the work, or are >>biased in selectively sampling only highly >>contaminated areas is absurd.

http://news.sciencemag.org/scienceinsider/2011/03/japan-soil-measurements-surprisingly.html

Meanwhile, on Wednesday the Japanese science ministry began to report measurements of cesium-137 in upland soil around the plant. The levels are highest from two points northeast of the plant, ranging from 8690 becquerels/kilogram to a high of 163,000 Bq/kg measured on 20 March from a point in Iitate about 40 kilometers northwest of the Fukushima plant…….the highest cesium-137 levels in some villages near Chernobyl were 5 million Bq/m2. .

No selective sampling, the Japanese Government is actively seeking out areas that may be a problem. It’s a mountainous area, mountains can act and do act like funnels.

.

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re post by: Shelby, on 27 March 2011 at 1:54 AM said:

None of these charts gives us any indication of actual pressure reading, therefor actual boiling points for the coolant. I know from designing race car engines that coolant pressure greatly impacts the boiling point and cooling system. I can only imagine the impact on a nuclear reactor cooling system. Can any of you experts be sure that they have the pressure required to keep the coolant from boiling at this or that stated temp? It seems you are missing a key element – actual system pressure.

Shelby, there is no ‘impact on a nuclear reactor cooling system’ to imagine. The relationship of temperature, pressure, and boiling point of water is the same no matter what the application – race cars or nuclear reactors. It’s simple physics.

Both Reactor Pressure Vessel and Containment Vessel pressures have been being reported. I don’t recall exactly which reports, but they’ve been there regularly, check TEPCO, JAIC, and NISA reports.

Also, they aren’t trying to avoid boiling. Remember, these are boiling water reactors. They are designed with the full intention that there is boiling going on in there, pretty much all of the time. Yes, it is at a higher pressure, and therefor temperature than the pot on your stove, that’s how they get the best scenario for turning massive turbines and generating electricity.

Now they’re trying to balance the various factors involved to keep the core from damage (e.g., not too hot, pressure not too high, no sudden major bursts of steam or other transients, etc), while minimizing onsite dose rates, and minimizing environmental releases. Boiling is expected.

You went on to say:

Another thought that comes to mind is, if the coolant is boiling would that constant expansion of the boiling water keep pressures erroneously stable despite the constant slow leaking of coolant (if such a leak is present).

In short, no. They know how much make-up water is being added to the system – that means that much is being off gassed or vented, one way or another. There is no way to get ‘erroneously stable’ pressure readings, unless the reading instrumentation itself is broken and then typically you either get a fixed reading that doesn’t change, or a zero reading, or a null reading. Right now they’re balancing input vs. output.

There may be leaks they aren’t aware of, which just means that what would be released to cool the reactor is in small part coming out somewhere they’re not aware of right now, but that doesn’t give erroneous pressure readings. The pressure is the pressure, and they pretty much know how much they’re putting in, which means they also know how much is coming out one way or another.

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EL, thanks for the data link. I wasn’t implying that the data didn’t exist; just that the news articles never seem to link to it.

This kind of upland deposition of caesium, by rain-out, can actually persist a long time. Upland areas of the UK are still monitored from Chernobyl fall-out., and sheep grazed on a some farms are checked for radioactivity levels before being released for sale.

As I have already expressed, I don’t see the evidence for harm from these levels, even though they are presented as scarily large and use specious multipliers on “normal levels”.

Some radionuclides bioaccumulate – some don’t.

“four broken down reactors sitting on the beach for a period of years” will make no difference to the local environment. Reactors in cold shutdown have no emissions.

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Numbers, from 24 March 2011
http://www.world-nuclear-news.org/RS_Exposures_and_progress_at_Fukushima_Daiichi_240311.html

“Tepco noted that the temperature of the containment vessel of unit 1 had built to some 400ºC, compared to a design value of only 138ºC. However, the strength of the component is such that it can withstand the stresses this imposes, said Tepco, and its structural integrity is expected to be maintained. “There is no substantial problem regarding the containment vessel’s structural soundness under conditions of pressure 300 kPa and temperature 400ºC.””

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re post by: sidd, on 27 March 2011 at 3:24 AM said:

Rational Debate kindly provided the link:
http://www.tepco.co.jp/en/press/corp-com/release/11032605-e.html

I find it troubling that I-132, I-133, Ru-105, Te-129 are detected. These have very short half lives, and must have been recently created. Daini is seeing I-132 as well.

Hi Sidd,

Are you sure you’re not confusing the far right column which lists limits with what was detected? For Dai-ichi they’re showing no detection of I-132 & 1-133 & Te-129.

For the Ru-105, not sure off the top of my head where it’s coming from, but don’t forget activation products and decay chains. (if you figure it out, post please, I probably won’t dig it out myself – not sure off the top of my head what activated Zr or Mo products would be expected, etc.)

I-132 actually wouldn’t be surprising if they’d found it. It’s the decay product of Te-132 which has a half life of 3.2 days. The Te-129 also wouldn’t be surprising if found, but it would be associated with Te-129m, with a half life of 34 days – and which I think has a 2/3rds chance, roughly, of converting to the much shorter half lifed Te-129. So neither one of those would be particularly surprising, I don’t think.

At Dai-ini they are showing some 1-132, a tiny bit above the minimum detection limit, and far below the quantity allowed for normal workers. Ru-105 wasn’t found one day, and was barely above minimally detectable limits the second day.

Te-129 was picked up slightly above minimum detection limits, both Te-129 & Te-129m. Both far below permissible limits. They didn’t pick up any I-133.

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The daily airborne emissions from this site are running around 10**17th bequerels just from iodine 131, according to the Austrian radiation monitors.
That indicates massive exposed fuel boiling off volatiles. As plenty of water has been pumped , there is clearly a loss of integrity, in the spent fuel pools or the reactor vessels or both.
The discussion about the reactor status is consequently somewhat peripheral. It is imperative that the source of this plume be located and then neutralized quickly, else the region will be burdened with centuries worth of radioactive legacy from cesium 137 and similar longer lived isotopes.
It is stunning to see that this national catastrophe is being fought by a pickup crew of contract workers and fire department draftees.
Japan has plenty of resources, why are they not getting used?

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re post by: bks, on 27 March 2011 at 12:10 AM said:

Joffan, appealing to the xkcd chart, damage to health to a population will occur at 10 microsieverts/hour for one year (87 millisieverts) so I do not understand your comments above, as the readings at the perimeter are 20 times that level, and stations 32 and 33 (MEXT data) 30 km away are at 3 to 10 times that level.

Plus we do not have data for the period following the major releases after the hydrogen explosions.

bks, as others have already stated I believe, those levels are transient. Not fixed. Most of the measured dose rate is being carried past those points in the atmosphere – and they are both decaying rapidly, and also being dispersed into the atmosphere. Many of the radioactive isotopes that are contributing to those dose rates have very short half lives. As a result, the more time that goes by, and the faster or more turbulent the wind, basically the faster those levels decline. So you can’t take readings like these and then just multiply them out as if the dose rate remained the same. If you do, you’ll almost certainly be over estimating the actual dose by literally orders of magnitude.
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MODERATOR
Prof Brook stated on this post:

This post provides an update to the various situation summaries at Fukushima Daiichi. Please switch to using this post for comments on the latest status reports and news to hand (the old one is now out of date). For general comments on, use the FD Open Thread, and for analysis of the event with respect to future lessons for nuclear power, use this post.(Preliminary lessons from Fukushima)

The up-date thread is being choked by the conversation regarding radiation levels etc. This can put off those reading the blog for real up-dates of the on ground situation.
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[deleted. Wrong thread. Several warnings have been given to all on this conversation.(see previous Moderator comment) Please move to Open Thread Fukushima]

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The first report i have seen about levels at Daichi Reactor 2

http://www.asahi.com/english/TKY201103260218.html

apparently TEPCO measured 500 millisieverts per hour in the basement of the turbine building for the No. 2 reactor six days ago, but did not see fit to share.

and unfortunately, according to

http://www.asahi.com/english/TKY201103260217.html

“The radiation found in the water has forced Tokyo Electric Power Co., the plant operator, to call a halt to efforts to install electrical cables to the reactors.”

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re post by: John Bennetts, on 26 March 2011 at 11:15 PM

John, thanks for the link to the earthquake aftershock video. That’s incredible, and you almost need to be able to play it slow motion.

I still wonder just how many of those aftershocks have had major ground movements at Dai-ichi itself.

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To the MODERATOR or Barry – I’m sorry, I was just working down thru the thread, and hadn’t gotten to the point of the first moderator warning yet. Consequently posted a few comments that were off topic, without realizing that they had been declared so. It’s far too easy in these things to not see warnings of this nature until after one has already posted. Just the nature of the blogging/bulletin board beast. Anyhow, I’ve seen the warnings now and won’t post any further replies to other’s earlier comments on that issue.

I just wanted to let you know that now I have seen the MODERATOR warnings, and that I wasn’t ignoring the warnings, I just hadn’t gotten down to them yet when I made those posts.
MODERATOR
Thanks RD -we actually thought that was probably the case with you, as you are usually only too happy to comly with the requests we make in this regard. Sorry we had to delete your comment (we know you put a lot of effort into them)- but we had to make a stand somewhere:)
Hope you had kept a copy as previously suggested. We appreciate your input.

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I think the following is the Japanese version of the results for the water at all 4 units, the levels for unit 2 look stupidly high to me and seem to be generating breaking news headlines as we speak.

Click to access 20110327001-4.pdf

(english version wasnt available to the time Im writing this comment)

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Re: criticality and geometry

Last time a random fuel configuration created a critical event was in Gabon, Africa, a couple million years ago.

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Since I am not a nuclear engineer, the concentration of radioactive I-131 in Unit 3 turbine bdlg water measured as 1.2×10^6 Bq/cm3 is not understandable to me. I have done the conversion to grams I-131 per liter and got 0.26 x10^-6 g/l or 0.3 parts per billion by weight.

The equation is: Bq = (m x Na x ln2)/ (ma x t1/2)

where: Bq is number of radioactive disintegrations per sec in the sample; m is the amount of radioactive element in grams; Na is Avogadro’s number 6.02 x 10^23, ma is the molecular weight of the radioactive element; and t1/2 is the half-life in seconds.

For the Unit 3 water reported by Barry above I-131 had 1.2 x 10^6 Bq/cm3 or 1.2 x 10^9 disintegrations/sec-liter. I-131 has a molecular weight ma of 130.9 and a t1/2 half-life of 8.02 years or 6.96 x 10^5 secs.

Plug those into the equation and you get m = 0.26 x 10^-6 or 0.26 micro-grams per liter, about 0.3 parts per billion I-131. Not highly concentrated.

When dealing with short lived radioactive isotopes, people commonly think that they must have just recently been made. Of course that’s not true. Eight days from when that sample was analyzed it would then contain 0.13 x 10^-6 g/l I-131. You cannot tell from an analysis, just how recently a radioactive element was made.
MODERATOR
Please move this conversation to Open Thread.

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Workers evacuated. Radiation levels 10 million times normal. ~ 10 Sieverts.

http://www.bbc.co.uk/news/world-asia-pacific-12872707
MODERATOR
Wrong information given by commenter.
Chrisma – please ensure your comments are correct as misleading information may give cause for concern to those reading these updates. Normally this would have been deleted but you have been corrected in the comments above.

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“Leaking water at reactor 2 has been measured at 1,000 millisieverts/hour – 10 million times higher than when the plant is operating normally”

1 sievert. Not 10 sieverts.

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Workers evacuated. Radiation levels 10 million times normal. ~ 10 Sieverts.

The linked article does not support Chrisma’s assertion. The rate mentioned in the article is 1 sievert.

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[deleted. Wrong thread. Please re-post on Open Thread Fukushima. See Moderator/Prof Brook’s notes on the material for this topic.]

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MODERATOR – TO REPEAT WHAT WAS POSTED EARLIER
(Off topic comments will be deleted. They have strayed again.)
Prof Brook stated on this post:

This post provides an update to the various situation summaries at Fukushima Daiichi. Please switch to using this post for comments on the latest status reports and news to hand (the old one is now out of date). For general comments on, use the FD Open Thread, and for analysis of the event with respect to future lessons for nuclear power, use this post.(Preliminary lessons from Fukushima)

The up-date thread is being choked by the conversation regarding radiation levels etc. This can put off those reading the blog for real up-dates of the on ground situation.
Please move the conversation to Open Thread. Further comments on this topic will be deleted and you will be asked to re-post in the correct thread (we have no facility to switch comments between threads)

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@ Leo Hansen 3:40 PM Moderator: I thought this discussion was about the current status of the Fukushima plant. Barry has the recent reactor 3 water analysis at the top of this column. I am only commenting on his reported concentration of 1.2 x 10^6 Bq/cm3 and putting his reported number in units that ordinary people can understan so that have a clearer understanding of the current situation.
MODERATOR
There is some overlap, and it is subjective, but the up-date post is read by the general public wanting to know the latest situation at the plant and long-winded discussions on subjects such as these tend to clog the thread and make it less accessible/more rambling to most. Many other comments regarding this topic are on the Open Thread Fukushima so yours would be a welcome and useful addition there. Thank you for your time and efforts – it is unfortunate that we do not have the ability to switch between posts.

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re post by: etudiant, on 27 March 2011 at 12:30 PM said:

etudiant, I would say that the dose rates, air samples, etc., around the Fukushima Dai-ichi site and surrounding countryside are far more meaningful and relevant than any estimates from Austrian monitoring equipment.

As plenty of water has been pumped , there is clearly a loss of integrity, in the spent fuel pools or the reactor vessels or both.

They’ve been venting steam to cool the reactors. That’s a far cry from a loss of containment integrity. I’m not saying that there isn’t a breach, I’m just saying that at this point, I don’t think anyone knows, and it isn’t reasonable to jump to conclusions. I think it’s also pretty obvious that they’re doing their darnedest to get things back under control so they don’t have to keep venting, and can get all releases stopped. Sensationalism over the situation and how bad it might be etc., won’t speed things up, it just adds to a lot of unnecessary panic that is already out there.

It is stunning to see that this national catastrophe is being fought by a pickup crew of contract workers and fire department draftees.
Japan has plenty of resources, why are they not getting used?

Why do you assume that they aren’t? Who is better qualified to make the connections and run fire engine pumper trucks? If those contractor workers regularly work nuclear power facilities, especially if they have experience with high level radiation areas as some outage contractors here in the USA do, then they’re the best suited to do this work. Same thing if they happen to be particularly good with electrical work, or piping or what have you. Not to mention that they are having to limit total doses to workers – so you can’t just take the same people and keep them working at the plant the entire time.

I see no reason what-so-ever to assume that the firemen and contract workers are anything other than some of the top folks that Japan has to deal with this, for the aspects that they are working on.

Not to mention that so far entire towns and much of their population have been wiped off the face of the earth, roads demolished along with every aspect of infrastructure, over 10,000 people confirmed dead and another 15,000 or more missing – in many regards the nuclear situation pales compared to the overall situation – and Japan has to devote a massive amount of their resources and expertize trying to deal with the devastation wrought by the earthquake and tsunami, not just the nuclear power station situation.

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MODERATOR?? Request for clarification please…. I think I just blew it with my replly to “etudiant” at 4:54, but I’m not honestly sure.

I mean, it’s not strictly tech/mech plant status – but on a plant status thread like this, is a single reply to someone else’s post ok, so long as it doesn’t turn into a running debate?

If not, how should we handle something like that? Post a reply here to the person stating only that we’re replying over on the open thread?

I’m just not sure how you folks prefer for this sort of thing to be handled or just where the line is for this thread, so to speak…
MODERATOR
It is a bit of a fine line and often a subjective decision, but probably the best response would be that anything borderline that get’s into long, detailed, technical discussion that progresses to take over the thread completely should go on the Open Thread. I will double check with Barry about this.

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[comment deleted. Wrong thread. Please re-post in the Open Thread Fukushima – see Prof Brook’s instructions at the top of this post and comments from the moderator down thread.]

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re comment by Moderator to me:

MODERATOR Thanks RD -we actually thought that was probably the case with you, as you are usually only too happy to comly with the requests we make in this regard.

Yes, I’m more than happy to comply with any of your requests. Hey, it’s your blog! :0) That, and you folks seem quite reasonable too.

Sorry we had to delete your comment (we know you put a lot of effort into them)- but we had to make a stand somewhere:)
Hope you had kept a copy as previously suggested. We appreciate your input.

No problem, I understand. I confess I don’t usually keep copies – but I’ve seen you folks suggest it several times, so that’s my own fault. It’s just awkward, especially if bouncing between threads. I’m not certain, but I may have lucked out this time – I had the thread open on two tabs, one to read, the other to post from… and so I think I may have that comment from the one tab that I hadn’t refreshed yet, ironically enough. Also, thank you for the compliments, they’re much appreciated!!

Kudo’s to you folks for the great work you do here!

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‘Leaking water at reactor 2 has been measured at 1,000 millisieverts/hour – 10 million times higher than when the plant is operating normally.

“We are examining the cause of this, but no work is being done there because of the high level of radiation,” said a spokesman for the plant’s operator Tokyo Electric Power Co (Tepco).

“High levels of caesium and other substances are being detected, which usually should not be found in reactor water. There is a high possibility that fuel rods are being damaged,” the spokesman added.’

http://www.bbc.co.uk/news/world-asia-pacific-12872707

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I should have added the headline for the BBC story:

‘Japan nuclear: Workers evacuated as radiation soars’

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