What happened at Fukushima Daiichi during the Japan earthquake?

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SteveElbows said:
As I had previously gone on about suppression chamber water temperature increases at reactor 2, I think I should mention that the temperatures stopped increasing and started to go back down, with the peak on September 25th. The only exception is the suppression chamber gas temperature, which continues to rise at a rate of approx 1 degree C per day.
... and #2 torus B radiation still slightly rising, with increased, but very slightly falling torus B radiation.
 
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zapperzero said:
http://www.meti.go.jp/english/earthquake/nuclear/iaea/pdf/20110911/chapter2.pdf

pp 203

Samples taken on June 20 in multiple locations, all approximately 500 meters away from reactor site, show Uranium, Plutonium, Americium and Curium.

EDIT: I don't remember seeing this in the first report to IAEA

Wasn't the first report done before June?

Anyway here is the press release & documents that were released at the time the soil analysis was first published:

http://www.tepco.co.jp/en/press/corp-com/release/11061105-e.html
 
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http://www3.nhk.or.jp/news/genpatsu-fukushima/20111002/index.html Tepco's internal investigation committee is preparing an interim report into the accident. According to the draft report, the explosion at unit 2 was not a hydrogen explosion. Whereas the damage at unit 4 and unit 2 occurred almost at the same time, the seismometer readings show only one hydrogen explosion which is thought to be the one which occurred at unit 4. The pressure in unit 2's suppression chamber dropped suddenly and it is thought that, for some reason, the suppression chamber was damaged.
 
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tsutsuji said:
http://www3.nhk.or.jp/news/genpatsu-fukushima/20111002/index.html Tepco's internal investigation committee is preparing an interim report into the accident. According to the draft report, the explosion at unit 2 was not a hydrogen explosion. Whereas the damage at unit 4 and unit 2 occurred almost at the same time, the seismometer readings show only one hydrogen explosion which is thought to be the one which occurred at unit 4. The pressure in unit 2's suppression chamber dropped suddenly and it is thought that, for some reason, the suppression chamber was damaged.

What else could sound like an explosion, manage to break containment but not be an explosion? Any word on that?
 
zapperzero said:
What else could sound like an explosion, manage to break containment but not be an explosion? Any word on that?

I guess that what Tepco is saying now is that the sound belongs to unit 4, not unit 2. I can't find more details about what is believed to have caused the containment failure.

Subsequent analysis of the data led the company to conclude that an explosion had occurred at the No. 4 reactor, but it "erroneously recognized" that something akin to an explosion had possibly taken place at the No. 2 unit, according to the report.
http://mdn.mainichi.jp/mdnnews/news/20111002p2g00m0dm083000c.html

http://www.nikkansports.com/general/news/f-gn-tp0-20111002-844020.html According to the records of solar-powered seismometer(s), explosion happened only once on 15 March at 06:12 AM. It is inferred that it is the explosion at unit 4. The reason why no hydrogen explosion occurred at unit 2 is that, by chance, [unit 2's] blowout panel was removed by unit 1's explosion, enabling the hydrogen gas to be released to the outside.
 
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""What else could sound like an explosion, manage to break containment but not be an explosion? ...""

a severe "water hammer" in a big vessel like a torus

as cautioned in those ORNL reports that used Brown's Ferry design as example.
Setup for water hammer is venting steam via too few safety valves, driving water in one region of torus up to saturation temperature...
 
jim hardy said:
""What else could sound like an explosion, manage to break containment but not be an explosion? ...""

a severe "water hammer" in a big vessel like a torus

as cautioned in those ORNL reports that used Brown's Ferry design as example.
Setup for water hammer is venting steam via too few safety valves, driving water in one region of torus up to saturation temperature...

yep. i read those too. i was wondering if tepco had a theory of their own.
 
http://www.aesj.or.jp/information/fnpp201103/chousacom/gb/gbcom_fukuichikamera20111003.pdf An Analysis of Fukuichi live camera as displayed on . It concludes that it is a valuable tool providing confirmation of a number of events such as venting - if not during the night - and that it is a lesson worth learning at other plants.
 
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http://www3.nhk.or.jp/news/genpatsu-fukushima/20111006/index.html A worker in his fifties who had been working for 46 days at Fukushima Daiichi, installing water treatment tanks, died on 6 October. He was taken to hospital on 5 October after feeling unwell during the morning assembly. According to Tepco, his radiation record being 2.02 mSv, it is difficult to think that radiation is the cause.
 
tsutsuji said:
http://www3.nhk.or.jp/news/genpatsu-fukushima/20111006/index.html A worker in his fifties who had been working for 46 days at Fukushima Daiichi, installing water treatment tanks, died on 6 October. He was taken to hospital on 5 October after feeling unwell during the morning assembly. According to Tepco, his radiation record being 2.02 mSv, it is difficult to think that radiation is the cause.

wrong link ?
 
tsutsuji said:
This was the general link for 6 October 2011, with the latest written article always on top. The direct link to the first article of the day is not provided (or I might not be good enough at finding it) until a second Fukushima Daiichi article is written during the same day. Here is the direct link : http://www3.nhk.or.jp/news/genpatsu-fukushima/20111006/1530_sagyoinshibo.html

http://www.google.com/hostednews/afp/article/ALeqM5gb7WCiUprUN0gRImtSYgz5Y8mm6w?docId=CNG.ba491593e56407f3b61e1ba743a820a0.4a1

http://www.ibtimes.com/articles/226528/20111006/japan-fukushima-nuclear-plant-radiation-death.htm
 
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http://www3.nhk.or.jp/news/genpatsu-fukushima/20111007/1600_osensui.html Tepco has received approval from surrounding municipalities and fishing cooperatives to perform the spreading of the water from units 5 and 6 after it is purified. The stored quantity has reached 17,000 tons or 90% of the storing capacity of the temporary tanks and the megafloat. Starting on 7 October at 02:00 PM, the water will be desalinated, cesium contamination will be brought to seaside resort standard level, and the spreading will be done at a 100 tons / day flow rate over a 1,200,000 m² area.
 
http://www3.nhk.or.jp/news/genpatsu-fukushima/20111008/1300_hx_kaishi.html Tepco is starting to extract the hydrogen from the unit 1 pipe on midday, 8 October, using nitrogen and a special low static electricity hose.
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111008_04-e.pdf page 2: "After the operation, we confirmed increase in hydrogen concentration, and so we are planning to do the replacement work again tomorrow".
http://www.yomiuri.co.jp/science/news/20111008-OYT1T00755.htm As a result of the nitrogen injection, the hydrogen concentration dropped from 63% to below 0.1%, but it rose to 3.9% again one or two hours later.

http://www.tepco.co.jp/en/news/110311/index-e.html new videos showing upper parts of units 1,2,3.
 
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tsutsuji said:
http://www3.nhk.or.jp/news/genpatsu...ould nullify any claims of a 'cold shutdown'.
 
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TEPCO says the hydrogen may have redistributed internally

http://www3.nhk.or.jp/daily/english/09_10.html
 
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LabratSR said:
TEPCO says the hydrogen may have redistributed internally

http://www3.nhk.or.jp/daily/english/09_10.html

That would imply the nitrogen purging was not very effective.
Given the severe constraints that TEPCO's people are working under, with very limited access to the reactor plumbing, they may be given the benefit of the doubt, but either the purging was a dud or the reactors are still emitting hydrogen.
Neither is reassuring and both may be true.
 
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LabratSR said:
More photos released

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111008_02-e.pdf

Direct link to the hi-res photo of U3 top: http://www.tepco.co.jp/en/news/110311/images/111008_05.jpg

The position of the fuel crane is still unknown. I think it must be under the overhead crane - I see no other place for it.

etudiant said:
Most interesting and very provocative information.
What is the source of this hydrogen?

Maybe they've tried to remove the hydrogen from the piping only, not from the whole PCV? The replacement of the whole inner atmosphere would be a bit longer work (it's a similar problem as the desalination of SFPs).
 
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http://www3.nhk.or.jp/news/genpatsu-fukushima/20111009/0630_steam.html [about the last released videos] Steam is not seen from the upper parts of units 2 and 3. According to Tepco, the quantity of steam is decreasing due to the temperatures surrounding the reactors being below 100°C. The video of unit 1 shows the collapsed roof, and does not reveal what happened below the roof. The video of unit 2 does not show any large damage. The blue coloured partitioning screen where equipment used during periodic inspections is stored, is visible. The video of unit 3 shows debris. Tepco has also released a picture of the central control room of units 1 and 2, where a pink coloured sheet protects from radiations [ http://www.tepco.co.jp/en/news/110311/images/111008_07.jpg ]. At present the maximum radiation in the control room is 0.01 mSv/h. Employees go there to check temperatures, pressures, water levels, etc.

Rive said:
The replacement of the whole inner atmosphere would be a bit longer work (it's a similar problem as the desalination of SFPs).
My understanding is that the replacement of the whole inner atmosphere is what they plan to do. For that purpose they needed to cut the pipe. Before cutting the pipe they needed to check the presence of flammable gasses. Then they found the hydrogen. As shown on the last released diagram : http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111008_01-e.pdf the valve between the PCV and the pipe is presently closed.

http://www.asahi.com/national/update/1009/TKY201110090343.html The pipe cutting work has started on 9 October after confirming that the hydrogen concentration is below 1%. Because the hydrogen concentration was close to 4% on 8 October, the cutting work had been delayed.

http://www.jiji.com/jc/c?g=soc_30&k=2011100900214 Hydrogen extraction was performed again on 9 October, and completed in the evening. Some pipe cutting work was also performed. Hydrogen concentration had been brought to below 1%.
 
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Anyone want to field some conjecture as to why a second worker dropped dead under similar circumstances with that other fella who came down with acute leukemia? Tepco has ruled out strenuous working conditions (he worked for just 3 hours a day), and has his cumulative exposure at just over 2 millSv.

We all aren't privy to the baseline health of these subcontracted employees prior to their foray at the plant, and it seems more likely that these deaths would be caused by either overwork or a pre-existing medical condition, but this dropping-dead business by nameless trenchworkers hired by subcontractors - after just brief stints on site - is starting to seem suspicious to me.

Guess my specific question is this - assuming these deaths are radiation related with tepco keeping it under wraps, is there a possible source of neutron exposure at certain areas of the site, or would that be out of the realm of possibility?
 
intric8 said:
Guess my specific question is this - assuming these deaths are radiation related with tepco keeping it under wraps, is there a possible source of neutron exposure at certain areas of the site, or would that be out of the realm of possibility?

Recriticality is possible, highly unlikely. But this person did not even go near the reactors themselves.

What's more likely is tyvek+gasmask+stress=heart failure - it is a possibility even in "healthy" individuals.

Also, there are very many people on site. Thousands at anyone time; the turnover is also high, most stay on for a month or two, then take other jobs.
 
intric8 said:
... this dropping-dead business ...
Every stressful jobs has similar statistics. Even sport is similar. There are usually two to five football players every year who just suddenly dies.

Of course, we cannot rule out that there is something more in it...

intric8 said:
... is there a possible source of neutron exposure at certain areas of the site, or would that be out of the realm of possibility?
Right now, there is no way to go close enough to the possible neutron sources (cores and fuel pools) (and the neutron emission of those possible sources is on dangerous level only in special circumstances).
 
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Rive said:
Every stressful jobs has similar statistics. Even sport is similar. There are usually two to five football players every year who just suddenly dies.

Of course, we cannot rule out that there is something more in it...


Right now, there is no way to go close enough to the possible neutron sources (cores and fuel pools) (and the neutron emission of those possible sources is on dangerous level only in special circumstances).

Entirely agree with Rive on this.
Afaik, there is no graceful, just drop dead option from massively excess radiation exposure, just a very messy and painful physical breakdown.
 
So I guess we all agree on two points:


First - it isn't very likely that the radiation did kill anyone yet (not speaking for coming decades, though)

Second - that pile of rubble of a plant is killing workers, just not through radiation. But what does the actual cause matter to the end result?
 
clancy688 said:
So I guess we all agree on two points:


First - it isn't very likely that the radiation did kill anyone yet (not speaking for coming decades, though)

Second - that pile of rubble of a plant is killing workers, just not through radiation. But what does the actual cause matter to the end result?

I value human life very much and do take any death no matter what the cause seriously, but if you look at the stats on any contstruction project or just plant operation... death and injuries are part of the operations.. that's why companies carry workers compensation and liability insurance... when you study the causes of these incidents, it is generally found that a large % are due to an employee not following directions/regulations.. (not all.. some are just accidents.. some are compaines taking short cuts...) all and all the numbers I have seen reported are quite small in relation to the number of employees/turnover of employees.. and the unknown physical hazards conditions of the work environment (excluding the radiation).
I do believe some on the thread are trying to make the situtation seem as it is something that the reports do not support.. I suggest that they do a comparison to a facility that is none nuclear and has simialar number of employees and hazardous working conditions.

Anyone out there in the insurance industrie? ... as the projected number of deaths and injuries are part of the equation that is used to charge the "premuim" on a construction project of a building. Equate it to the higher preceved risk of those under 25 driving... if you use a car its a known fact that some will be in an accident and some will lose their life.

Companies in the US carry what is called "Experience Modification" it is a calculation of past performance that insurance companies use to asses the risk value of a company.. the lower the mod the lower the premium.. and usually the better their saftey program is or inforced.

So I guess the question is "we know that the employees are put in a dangerous enviroment,(they also are not being forced to be there) but what is the solution... do not attempt to do anything at the plant? ie.. just walk away? That would be the same logic as everyone park your cars!

I do believe some here just can't wait for bad news, so they can TEPCO bash.

Edit: General info not referring to clancy, glad to see clancy's acknowlegement that it's not likly to be rad related.
 
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intric8 said:
Anyone want to field some conjecture as to why a second worker dropped dead under similar circumstances with that other fella who came down with acute leukemia? Tepco has ruled out strenuous working conditions (he worked for just 3 hours a day), and has his cumulative exposure at just over 2 millSv.

We all aren't privy to the baseline health of these subcontracted employees prior to their foray at the plant, and it seems more likely that these deaths would be caused by either overwork or a pre-existing medical condition, but this dropping-dead business by nameless trenchworkers hired by subcontractors - after just brief stints on site - is starting to seem suspicious to me.

Guess my specific question is this - assuming these deaths are radiation related with tepco keeping it under wraps, is there a possible source of neutron exposure at certain areas of the site, or would that be out of the realm of possibility?
Please substantiate claims regarding the circumstances of the workers' deaths, and please provide the evidence or citations of nameless trenchworkers dropping dead. Leukemia develops over time. One doesn't just come down with it.

WSJ said:
Tepco said only that a male worker in his 50s became ill during a meeting Wednesday morning, before his shift started. He was taken to a hospital immediately, and died the next morning.
http://online.wsj.com/article/SB10001424052970203388804576616154250660860.html

It is not clear the cause of death.

It would seem unlikely a neutron source - spent fuel or transuranics undergoing spontaneous fission would be located outside of containment.
 
Astronuc said:
It would seem unlikely a neutron source - spent fuel or transuranics undergoing spontaneous fission would be located outside of containment.

Surely in respect of Fukushima 1;2 and 3 the term 'containment' is no longer applicable ,it does not hold water
 

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