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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”

@Shelby:

I’m actually surprised there hasn’t been more of these events given, the seriousness of the situation, the stress the workers have been under and length (2 wks) this has been going on. Tepco managers seems to be doing a good job of limiting exposure given all they have to deal with.

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I have said it before and I’ll say it again, I think they will have to flush most of this radioactive water out to sea given the volumes involved. The normal way to remove radioactive material from water is to use ion exchange resins to remove the radioactive isotopes. These are used in normal operation to remove the small amount of radioactive material (neutron induced and fission products) that is mobilized. Whether the resins could handle this load is not even relevant, because they would be swamped by the seawater. Evaporation followed by burial somewhere? That would be much worse, even if possible. Dilution, dilution, dilution is the only solution.

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The water analysis certainly speaks of fuel damage somewhere, with a path to release. I guess the fisison products are more mobile because they’ve broken free of the stable oxide that the fuel itself is in – assuming that the absence of actinides in the TEPCO analysis summary means they weren’t present in meaningful quantities. Which perhaps implies a cladding failure but not wholesale fuel rod burn/collapse – jumping quite a long way on not much information.

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@Joffan,

Yes they should be able to detect any actinides in their sample, so the lack is encouraging. That doesn’t mean there aren’t fuel pellets that have accumulated at the bottom of the reactor. Oxides of the actinides have low or essentially zero solubility in water (from my CRC handbook). There may be some chlorides formed given the heat and salt water and they have some solubility, but I don’t know how likely that is.

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Cited again, here is the specific report of nuclides found in the water. Nuclear export with the Times reports that high levels of radioactive cobalt and molybdenum point to long standing corrosion problems at the plant (and concerns with the extended use of sea water): “Both materials typically occur not because of fission but because of routine corrosion in a reactor and its associated piping over the course of many years of use.”

The fact of the matter, we wouldn’t be talking about any of this (including additional concerns about reactor containment) had these workers (subcontracted and poorly trained by TEPCO) not stuck their feet in the water.

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Hank Roberts, on 26 March 2011 at 3:24 AM said:

bioaccumulation

I assume that was a reference to my assertion about dilution. I didn’t say it was a good solution, I just don’t know what else they are going to do. I hope they come up with one, but I can’t see what it is going to be.

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EL, we might still have been talking about this even with better training of the affected workers. The radioactive water was still there, and once the workers’ dosimeters were checked as OK (which they were), the response team would have had to find the cause.

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I must say that I’m astonished that 2 weeks out, there is still not someone in the nuclear industry running an active blog/timely of breaking reports. It’s crazy that we have to go out and forage google for stories than bring them back here and post them. It’s a very arcane way to build a data/timeline in the 21rst century. I’m grateful to have this blog comments section to share links and opinions, but the BNC blog itself is not a timely source of data / timeline / reports. Back to foraging Google I go……

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Why are all my comments awaiting moderation before they get posted? Are you really that afraid of my brain? Stop this nonsense.
MODERATOR
You are on moderation because of various violations of the commenting rules. One of your posts held overnight for moderation has already been edited for linking to an article which did not support your personal opinion/unsupported hearsay.]

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Regarding the common spent fuel pool, with the reported 73℃ temp on March 24th that I thought worthy of mention, and news that they had turned on the cooling system around the same time. Well it is down to 53℃ as of 15:20 March 25th according to the box on the bottom right corner of the first page of this status report:

Click to access en20110325-5-3.pdf

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@Steve Elbows

I find that results for Cl-38 very puzzling in that report you linked to. The activity is very high, but the only way to get Cl-38 is from the neutron activation of Cl-37 (nat. abundance of 24.5%). The half-life is 37.4 min. so it would have to of been recently produced, which would mean there is nuclear fission producing neutrons going on in that reactor as we speak.

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William Fairholm, on 26 March 2011 at 7:30 AM said:

@Steve Elbows

I find that results for Cl-38 very puzzling in that report you linked to. The activity is very high, but the only way to get Cl-38 is from the neutron activation of Cl-37 (nat. abundance of 24.5%). The half-life is 37.4 min. so it would have to of been recently produced, which would mean there is nuclear fission producing neutrons going on in that reactor as we speak.

—-

Perhaps we should return to the ignored question of where those 13 neutron beams observed by TEPCO came from?

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@Steve Elbows

I see how we differ. The 19s is for a metastable state above the ground sate. I don’t know what percentage of each state is produced in nuclear fission, but the 19s state would be gone before it could be measured outside the reactor.

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William Fairholm, on 26 March 2011 at 8:07 AM said:

Regardless, the presence of Cl-38 is very concerning as there is only one conclusion. Nuclear fission is occuring in this reactor.

———

Perhaps we should return to the ignored question of where those 13 neutron beams observed by TEPCO actually came from?

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Concerns about Reactor No. 3 have surfaced before. Japanese officials said nine days ago that the reactor vessel may have been damaged.

Hidehiko Nishiyama, deputy director-general of the Japan Nuclear and Industrial Safety Agency, mentioned damage to the reactor vessel on Friday as a possible explanation of how water in the adjacent containment building had become so radioactive.[deleted unsupported hearsay presented as fact – link supplied did not contain this information] http://www.nytimes.com/2011/03/26/world/asia/26japan.html?hp

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The only thing that could produce As-74 by neutron activation is Ge-73 (7.76% nat. abundance) which has a fairly large neutron cross-section of 14 barns. But where would germanium come from? It isn’t in stainless steel is it? Or any other reactor component.

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I spent many years as a process troubleshooter in the petroleum industry. I learned that when faced with analytical results that seemed unusual, you always had to suspect the lab results too.

A second or a third sample is called for in those cases. Even then, lab methods can have interferences, and we would have to submit a standard sample to see what the lab would say.

Maybe nuclear analytical methods are much better, but when faced with unusual results, don’t jump to conclusions, instead recheck.

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@Leo Hansen

Yes, I agree. Just this was so odd. And it would seem they were looking for Cl-38 activity unless there is some automatic software that is converting gamma ray energies into assigned nuclei which got confused. But I agree it must be checked. By the way, here is a better mass yield curve which shows how little atomic mass 74 is produced in fission. It is off the logarithmic chart.

http://www.science.uwaterloo.ca/~cchieh/cact/nuctek/fissionyield.html

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@Joshua

Cs-134 from thermal neutron fission of Pu-239, and Pu239 will always be present at some level in a LWR due to neutrons on fertile U-238.

Mo-99 from thermal U235 fission: direct yield of 7.7×10-4, accumulated yield of 6.1×10^-2.

So Tc-99m from Mo-99 beta decay: 65.9 hrs: invented at BNL, where I work, sometimes :)

The Technetium-99m Generator

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@Rational Debate

Thanks for your great summary of the variety of reactor designs, I’m working my way through the links and indeed having fun learning about all the different designs!

I’m a theoretical physicist, mostly a particle physicist but with some training in nuclear physics, and I have not much experience with nuclear reactors, beyond knowing some of the general principles on which they operate, and having seen the insides of research reactors. So terms like Gen I,II,III,IV were opaque to me, and the state of the power generation industry and plans for the future were unknown to me. So I found your post a very useful intro.

I may get back to you with some questions in a more appropriate thread.

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re post by: David Kahana, on 26 March 2011 at 4:28 PM:

You are certainly welcome David! I’m glad my post was useful – and especially that you are having fun checking out the various designs and so on. I know it’s something that I’ve always been intrigued by myself and have kept an eye on over the years. :0)

I’ll be happy to answer anything I’m able to. Right now, it would seem that the “open thread” is one where almost anything can be discussed. https://bravenewclimate.com/2011/03/21/fukushima-open-discussion/#comment-121156

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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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David Kahana, on 26 March 2011 at 4:31 PM said:

The Cl-38 seems crazy.

The more I think about it the crazier it seems. The neutron cross-section of Cl-37 is 430 millibarns, which isn’t small, but isn’t large either. To work back from the observed activity, through the delay before measurement, through the transport mechanisms, to the neutron flux that would produce this activity, to the fission rate that would produce this neutron flux, would be very complex and fraught with uncertainties. Much easier to get another “confirming” measurement, done very carefully, to see if this is a real problem.

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One of the frustrating things about the situation in Japan is that we get reports that suggest that alarming things are happening in Japan, like the Cl-38 activity which suggest fission continuing in the core and the observation of neutron flux in areas around the plant which suggests there is Pu-240 that has escaped, but then no follow up reports. These would be serious problems if true. You would think they would follow up and find out if these are true problems. But then nothing follows. Maybe they find there are no problems and so no need to report a non-problem, but it is frustrating to be left hanging with no further information.

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re the Cl-38…. I don’t’ know off the top of my head, and assuming that there is Cl-38 – are you folks considering all the various decay chains from activated corrosion products, radiochemistry, etc?

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@Rational Debate

There are no elements let alone reactor components that could be a source other than Cl-37. You would have to get into two or more neutrons being absorbed. Not going to happen, especially versa the Cl-37 we all ready know is there. Either bad measurement or fission was active in the core shortly before the the water was released to the turbine building.

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William

I keep bringing up the 13 neutron beams that Tepco reported observing from 1.5km away (starting on March 13th) to support your fission concerns. The report was a blip on the screen then it was erased from the news cycle with no real explanation. My understanding is only fission can cause neutron beams of that size?

Comments? Anyone?

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

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From the latest JAIF earthquake report:
“high radiation level in the water was also found in the basement of the turbine building of Unit 1, 2 and 3. The level of radiation on the surface of water was more than 1000 millisieverts (mSv) per hour in Unit-2, 60mSv in Unit-1, 750mSv in Unit-3. NISA officials believe the contaminated water likely came from the reactor rather than the spent fuel pool because the radionuclide detected contained in the fuel and some had short half-lives. TEPCO took immediate action to drain off the water because current situation would cause delay in recovery work. TEPCO already started draining off the water in Unit-1, and also preparing or considering drain off the water in Unit-2 and -3. The water would be sent to
condensers in the turbine building.”

Click to access earthquakereport32.pdf

Wow. Those are very high levels. Where are the condensers and how much water can they store there? This has to eventually go to the sea as more water continues to leak. Must be lots of damage to the fuel.

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From the lastet JAIF reactor status report, the temperature of the SFP 2 is high. 71℃ (26th 21:00)
70℃ (27th 05:00)

Click to access ENGNEWS01_1301210659P.pdf

They must not have any cooling going on and are adding water to make up for evaporation. They also list the temperature of SFP 4 as being immeasurable since the 24th, 11:00. No note on SFP 3 temperature. Last information on saw on SFP 1, the temperature was around 50℃ and that was for several days. SFPs 5 and 6 are fine.

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Exposure levels have been estimated for those workers who received large doses of radiation. From the IAEA report “the level of local exposure to the workers legs was estimated to be between 2 and 6 sieverts.” Those are definitely radiation burns. How they go from local exposure to whole body dose I don’t know how to calculate, but I would think they have exceeded the 250mSv they are allowed to receive even in this emergency situation, especially given that they were also receiving a whole body dose from that water they were standing in. I would expect long term health consequences for these workers.

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

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Whoah, William Fairholm — you’re leaping from a couple of facts quoted then making statements: A quoted “‘estimated to be between 2 and 6 sieverts'” then a leap into opinion phrased as fact: “Those are definitely” then speculation: ‘I don’t know how to calculate but would think” and “I would expect” — and earlier “they must not have any cooling ….”

Can you give some basis for these beliefs? They don’t follow clearly from the bit of fact you give first.

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@Hank Roberts

I used definetly radiation burns, because they are estimating the exposure to their legs from the damage done to them or that is my reading of this report. I emphasied that because there was earlier speculation on hot water burns. Levels of 170 mSv exposure were reported for these workers which I take to be from their dosimeters. Adding the direct contact exposure to their legs at such a high level, I think it is reasonable to get to near or above 250 mSv total exposure without doing the full analysis. I think this is less speculative than that on a lot of the information we have been receiving, but that is my reasoning and you may disagree with it .

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re posts by, 1st one: William Fairholm, on 28 March 2011 at 1:33 AM said:

….

“the level of local exposure to the workers legs was estimated to be between 2 and 6 sieverts.” Those are definitely radiation burns.

No, they’re not definitely radiation burns. If they had erethema, it could also be from water temperature or from chemicals in the water – it could even be from a reaction by the skin to harsh detergents that are often used to wash anti-contamination garments which were then brought into close contact with the skin when the anti-c’s got wet. We’ve seen that before – it can be very surprising what can cause even very nasty looking bright red skin.

It also very much sounds as if they are estimating the dose from how the skin looked – a mistake, because as noted, too many other things can cause skin reddening too. It also doesn’t fit with the reported surface dose rate of the water.

So we have a number of factors here that don’t match up. That means that actions should have been taken, rapidly to try to clear up some of the key factors. In other words, a couple of samples of the water that are then analyzed thoroughly.

Even if we take the new reports of the water, it was 750 – which still doesn’t give a high enough dose. So, we don’t know. They might, they may have better information by now, but it wasn’t released in this report. We still have no idea if there are any radiation burns.

but I would think they have exceeded the 250mSv they are allowed to receive even in this emergency situation, especially given that they were also receiving a whole body dose from that water they were standing in. I would expect long term health consequences for these workers.

The whole body dose was recorded by the dosimeters, and was 170-180 mSv. They may do more detailed dose reconstructions if they can, and that may increase it some, but I see no reason to assume that it was over 250 – let alone that it was high enough to expect any health effects unless you are meaning a possible (not certain) calculated incremental increase in cancer risk many years down the road. That, possibly. Any immediate health effects? Very unlikely if chest dosimeters readings were 170 mSv.
MODERATOR
This conversation is starting to ramble off topic. Please continue this discussion on Fukushima Open Thread 2 or the posts will be deleted and you will be asked to re-post.

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@William – erethema from radiation doesn’t look any different than erethema from chemicals, allergies, hot water, etc.

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@Rational Debate

I’m glad you think your assessment is better than the “National Institute of Radiological Sciences in the Chiba Prefecture” mentioned in the item, but let me be sceptical of your expertise and conclusion especially since you didn’t examine them or know the circumstances of their assessment and treatment. I will take their assessment as given until different information arises. The long term consequences that I know of are mainly increased cancer risk, but I didn’t exclude any other, because I haven’t read extensively on the matter. We can quibble over what their total exposure is, I wasn’t trying to make that definitive, just a best guess.
MODERATOR
This conversation is drifting away from this thread and into the Open Thread arena. Please switch to Fukushima Open Thread 2 to continue discussion.

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William Fairholm, you’re mixing up direct quotes with statements of belief.

Please stop doing this. Cite your sources, quote them directly, use quotation marks around the quotes.

Put “I think” or ‘In my opinion” before other statements.

This is an exact quote with enough context to understand it:

“For two of the three workers, significant skin contamination over their legs was confirmed. The Japanese authorities have stated that during medical examinations carried out at the National Institute of Radiological Sciences in the Chiba Prefecture, the level of local exposure to the workers’ legs was estimated to be between 2 and 6 sieverts.”
From:
http://www.iaea.org/newscenter/news/tsunamiupdate01.html

Everything else is speculation.

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@Hank Roberts

Maybe as matter of style I chould use longer quotes, but I have used quote marks, and I thought the reference was obvious in context. I assume that people have read the link and are following the context, but I could see as people dip in and out of these thread, they may not see that.

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Early I made a statement that they were not cooling SFP 2. Although I believe that was correct, I decided to look back at all the temperature records in the last 25 JAIF reactor status reports. This seems to be a temporary condition. They may have had to turn it off for a while for some reason. I shouldn’t have stated they had to add water. They seemed to have turned it back on given the last temperature reading. Here is the record for the Temperature of Unit 2 SFP.

Temp. Date/time
67℃ (27th 09:00)
70℃ (27th 05:00)
71℃ (26th 21:00)
57℃ (26th 13:00)
57℃ (26th 9:30)
52℃ (25th 23:00)
50℃ (25th 18:00)
28℃ (25th 10:00)
28℃ (25th 06:00)
40℃ (24th 17:00)
45℃ (24th 13:00)
52℃ (24th 01:00)
51℃ (23rd 04:20)
51℃ (22nd 23:00) 22nd 16:07-17:01 Water injection to SFP was conducted (about 18 tons).
53℃ (22nd 11:20)
51℃ (22nd 06:00)
50℃ (21st 14:25)

On the March 20 22:00 report the following first appears in red:
“20t 15:05, operation of seawater injection to the spent fuel pool was conducted”
They do not attach a date to this event in the log, but since it first appeared in the report of this day, I assume this is the date it occurred. This is separate from the adding of water on the 22nd, which I believe is fresh water.

Sources found at http://www.jaif.or.jp/english/

While doing this I also compiled information on Units 5 & 6.

Temperature of Unit 5 & 6 SFPs
Unit 5 Unit 6 Date/time
37.8℃ 21.0℃ (27th 14:00)
34.6℃ 20.5℃ (27th 06:00)
43.7℃ 29.0℃ (26th 11:00)
42.8℃ 30.0℃ (26th 14:00)
43.7℃ 29.0℃ (26th 11:00)
42.3℃ 27.0℃ (26th 06:00)
38.8℃ 23.8℃ (25th 20:00)
37.9℃ 22.0℃ (25th 18:00)
39.5℃ (25th 10:00)
49.3℃ 20.0℃* (25th 06:00)
50.9℃ (25th 01:00)
49.0℃ (24th 17:00)
47.7℃ 27.0℃ (24th 13:00)
45.1℃ 23.5℃ (24th 05:00)
42.6℃ (23rd 22:00)
41.1℃ 19.0℃ (23rd 18:00)
39.0℃ 19.5℃ (23rd 14:00)
39.0℃ 20.0℃ (23rd 12:00)
37.8℃ 20.0℃ (23rd 09:00)
36.6℃ 21.0℃ (23rd 06:00)
34.2℃ 24.5℃ (23rd 00:00)
33.5℃ 27.5℃ (22nd 17:00)
37.5℃ 25.0℃ (22nd 11:00)
37.4℃ 23.5℃ (22nd 08:00)
35.8℃ 30.0℃ (22nd 01:00)
42.3℃ 36.5℃ (21st 17:00)
42.3℃ 36.0℃ (21st 16:00)
39.5℃ 32.0℃ (21st 05:00)
35.1℃ 28.0℃ (20th 16:00)
36.1℃ 36.5℃ (20th 09:00)
40.1℃ 52.0℃ (20th 03:00)
67.6℃ 65.0℃ (18th 22:00)
65.5℃ 62.0℃ (18th 15:00)
65.9℃ 63.0℃ (18th 08:00)
* Average of two different numbers on two consecutive reports, 19.5℃ and 20.5℃

They do not list temperatures for Unit 1, but I’ve seen numbers elsewhere of around 50℃, a few days ago. I could track it down if people are interested, I posted the link earlier.

For Unit 4 they list “Unmesurable (since 14th 04:08)” or later reports “(24th 11:00) (immeasurable)”

For Unit 3 SFP, I didn’t see any mention of temperature, but I might have missed one.

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Shelby, on 27 March 2011 at 11:34 PM said:

William
I keep bringing up the 13 neutron beams that Tepco reported observing from 1.5km away (starting on March 13th) to support your fission concerns. The report was a blip on the screen then it was erased from the news cycle with no real explanation. My understanding is only fission can cause neutron beams of that size

Sorry Shelby, I`ve been distracted by other matters. I have dealth with this earlier. Starting at William Fairholm, on 24 March 2011 at 5:00 AM said:

Let me be clear, the issue of neutron counts outside the reactor is a different concern, than if there is induced fission going on inside the reactor. You could not have enough fissile material in one place with a moderator around it to produce induced fission outside the reactor. Just the very low level of neutrons detected would preclude that possibility. The level is so low it may be from cosmic rays. These are less frequent the higher the energy. So even if the levels are above the usual cosmic ray background, they may just have measured a particularly energetic event. To confirm actinides outside the reactor they have to measure them. I would suspect the spontaneous fission of Pu-240 as the only likely candidate. Large amounts made during reactor operation and a significant spontaneous fission rate. If they had gamma spectrometers, they could detect the associated gammas with the alpha decay of Pu-240, which is millions of times higher than the Sf rate. If they got close enough they could measure the alpha decay directly. (only a few centimetres in air). Look back for references I`ve made for this.

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The latest IAEA report:

“IAEA Briefing on Fukushima Nuclear Accident (27 March 2011, 13:30 UTC)
1. Current Situation

The situation at the Fukushima Daiichi plant remains very serious.

The restoration of off-site power continues and lighting is now available in the central control rooms of Units 1, 2 and 3. Also, fresh water is now being injected into the Reactor Pressure Vessels (RPVs) of all three Units.

Radiation measurements in the containment vessels and suppression chambers of Units 1, 2 and 3 continued to decrease. White “smoke” continued to be emitted from Units 1 to 4.

Pressure in the RPV showed a slight increase at Unit 1 and was stable at Units 2 and 3, possibly indicating that there has been no major breach in the pressure vessels.

At Unit 1, the temperature measured at the bottom of the RPV fell slightly to 142 °C. At Unit 2, the temperature at the bottom of the RPV fell to 97 °C from 100 °C reported in the Update provided yesterday. Pumping of water from the turbine hall basement to the condenser is in progress with a view to allowing power restoration activities to continue.

At Unit 3, plans are being made to pump water from the turbine building to the main condenser but the method has not yet been decided. This should reduce the radiation levels in the turbine building and reduce the risk of contamination of workers in the turbine building restoring equipment.

No notable change has been reported in the condition of Unit 4.

Water is still being added to the spent fuel pools of Units 1 to 4 and efforts continue to restore normal cooling functions.

Units 5 and 6 remain in cold shutdown.”

http://www.iaea.org/newscenter/news/tsunamiupdate01.html
MODERATOR
William – you should probably move this up-to-date information to the later up-date Fukushima thread for 26th March. Unfortunately we don’t have the facility to move comments between threads so you will have to cut and paste yourself.

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The more I think about it the crazier it seems. The neutron cross-section of Cl-37 is 430 millibarns, which isn’t small, but isn’t large either.

You’re right, the cross-section is not especially large, and if the Cl-38 were produced by neutron activation of the salt in the seawater by some ongoing fission in the reactor, then I don’t see how it can be there without also seeing Na-24, with half-life of 11 hrs, and probably many other activities from other impurities in the seawater, too.

To say they’ve got Cl-38 definitively, they need to observe a beta endpoint energy pretty near to the maximum, 4916 keV, as well as the two characteristic Ar-38 gammas at 1642 and 2167 keV, and these in the right relative ratio.

The activity level they report is very high, in the MBq range, so I imagine if they have a large enough sample of the water then they can definitely see the two gamma energies very well. But I suppose it still may take a little counting to get a firm fix on the beta endpoint, since the beta energy spectrum drops pretty quicky near the max.

I tried to think of some route, to get either excited Ar-38, or Cl-38 alone, but I can’t come up with anything plausible with single neutrons at thermal fission energies, nothing with any cross-section to speak of: eg the (n,3n) reaction on Ar-40, which is about 1% in air, has a cross-section in the microbarn range. You’ld need 3 GeV protons on U or Pb to get even a few millibarn cross-section for producing Cl-38. And those kinds of energies are out of the question, of course, they’ld have to be from cosmic rays.

I haven’t seen Cl-38 mentioned in the later analyses of this water, and I notice that they do mention some other isotopes that went away on more careful analysis.

So I think you’re right, it was likely a case of a measurement error of some kind.
MODERATOR
This over night discussion is becoming rambling and threatens to clog up the update thread. Please move it to the Fukushima Open Thread 2.

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@Linus
Basically the same radioisotopes are produced in the fission of Pu and U fission, in somewhat different proportions. Strontium isn’t volitile like Cesium and especially Iodine, so it is harder to mobilize. I would think they would be looking for it though.

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RE: Sr-90. I assume that they are determining the various radioisotopes through their gamma emissions. Sr-90 is a pure beta emitter, so it would not be detected that way.

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@nkinnear

Ok, I didn’t remember that, but given that, I would still think they would be looking for it in their water samples, given the importance of this isotope in long term hazard analysis. They may have to do some radiochemistry to separate it from all the other radioisotopes, so that would take longer. It is really only through bioaccumulation and ingestion that it would be a real problem, so maybe they are putting off that analysis. It would be interesting to know if it was present, but not that important to know right now. Eventually yes.

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To the World, From Fukushima, Japan

I live in Fukushima-City, Fukushima where is 50 km from Fukushima-Daiichi Nuclear Plant. After the explosion, we have spent One Month and many people, who have no money to escape, have lived with toil and tears. Also, we are very scared because more terrible accident waiting to happen, like Chain Reaction and hydrovolcanic explosion.
Why we are scared is that TEPCO and the government is not working to help our life and to combat environmental pollution. They are only suppressing information about the situation of the Fukushima-Daiichi Plant. Even the prime minister of Japan, Naoto Kan, say nothing to us. Additionaly, people who lives in Tokyo, capital city of Japan, does not have demonstration against this serious situation, so people living in Fukushima don’t know what to do.
The environmental pollution effects our jobs since there are endless rumors about radioactivity. if this goes on, we will run out of energy and die.

Please HELP US.

Nobuhiro Miyagi

960-8061 Satsuki-cho, Fukushima-city, Fukushima, Japan.
nobuclare@gmail.com

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