Fukushima Daiichi nuclear disaster

[Open Sauce]

How much of that is the weight of fuel? .

See link I posted. Fissile wt% = 1.7% U235 for a BWR.

 

[Open Sauce]

Do the high levels in reactors 1,2 and 3 mean that vital work can't take place, thereby prolonging the leaks? Or do they have robots to do the jobs the humans can't?

Until last week, I don't think we had any idea how bad the operating conditions were, now it is emerging. They barely had access to control room and when they did there were no lights. Lighting is being restored. It seems many of the instruments are inoperative or unreliable. I don't know what the usual situation is, but given they cannot determine where leaks are, what radioactivity is in certain places then much of the instrumentation is dead or non-existent. Everything they are doing seems to be ad-hoc and little seems to be working so I doubt there is much automation they already have and so any robots will need to be brought in and adapted.

 

[laptop]

Or do they have robots to do the jobs the humans can't?

Maybe one or two: New Scientist reported the first going in on 17/18 March.

However:

Monirobo weighs some 600 kilos and is limited to a speed of 2.4 kilometres per hour. It has to carry heavy shielding because many electronics, especially cameras, are highly vulnerable to the effects of radiation.

 

[elbows]

Looks like they finally managed to do something about the leak into the sea.

http://english.kyodonews.jp/news/2011/04/83381.html

The outflow of highly radioactive water into the Pacific Ocean from the crippled Fukushima Daiichi nuclear power plant has stopped after the injection of a chemical agent, Tokyo Electric Power Co. said Wednesday.

In a bid to stem the leak, the utility, known as TEPCO, injected 1,500 liters of ''water glass,'' or sodium silicate, and another agent near a seaside pit where the highly radioactive water had been seeping through.

The nuclear plant has been severely damaged by the March 11 mega earthquake and ensuing tsunami.

 

[mincepie]

Do the high levels in reactors 1,2 and 3 mean that vital work can't take place, thereby prolonging the leaks? Or do they have robots to do the jobs the humans can't?

They said this a few days ago:

A Tepco executive said yesterday he isn’t optimistic about the prospect of containing damage at the Fukushima Dai-Ichi nuclear power plant’s No. 3 reactor.

“I don’t know if we can ever enter the No. 3 reactor building again,” Hikaru Kuroda, the company’s chief of nuclear facility management, said at a press conference.

 

[Dr Jon]

See link I posted. Fissile wt% = 1.7% U235 for a BWR.

I gather that the 1.7% refers to the enrichment of the fuel by weight; that is the % of fissile Uranium-235 the (Uranium Oxide) fuel contains. The remainder would be U-238.

There's some interesting info here:
Nuclear Fuel Fabrication

Reactor 3 was using MOX:

Mixed oxide (MOX) fuel elements, as assigned in the reactor 3 power station of Fukushima I, do not only contain uranium, but also some percent plutonium as fuel. In the enterprise of the reactor plutonium is always formed from the uranium, so also pure uranium fuel elements contain plutonium after some time. However, in a reactor, which is loaded with MOX fuel elements, the core contains two- to five-times as much plutonium as a reactor core containing uranium and operating for a considerable time. In addition, the core contains much higher portions of transuranic elements after some time of operation such as neptunium, americium and curium.
During a core meltdown also larger quantities of these materials are set free and can enter the environment. Like uranium, also plutonium, neptunium, americium and curium are present as dust particles or are bound to dust particles.

All these materials are only set free to a considerable extent from the melt at temperatures well above 2,000 °C. The differences between an uranium nucleus and a MOX core play a rather small role for a core meltdown accident regarding the effects on the environment according to the BfS.

This Mixed oxide fuel (MOX) page suggests that there is 7% Plutonium (as PuO2) in MOX fuel.

I'm still no nearer to having a definite figure for the weight of fuel in a fuel assembly. If the 273kg quoted earlier is the total weight of the assembly, including Zirconium cladding, rivets, bolts, etc. then I would guess that we're looking at something like 200kg for the fuel alone. This would make my earlier calculations quite scary, IF my assumptions are correct - which is unlikely. As I have said, there are all kinds of complicating factors in this and, as Laptop pointed out, disagreements over how toxic Plutonium actually is.

I find it depressingly tragic to note that over 3 weeks have passed and we are still no closer to resolving this emergency. The nuclear genie is out of the bottle and seems determined to give our asses a kicking. If any good comes from this, it will likely be a reassessment of our concepts of safety, risk and responsibility.

 

[elbows]

Some sort of belated, half-hearted evacuation of certain people from Iitate village due to start in a week. Better than nothing but still a disgrace.

http://www3.nhk.or.jp/daily/english/06_20.html

 

[two sheds]

Just came across an interesting quote from Richard Feynman: "For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled".

He said it about the Challenger Space Shuttle Accident, and was being quoted in reference to biofuels but it also seems very pertinent here.

 

[Dr Jon]

It just keeps getting worse:

Fragments of incredibly dangerous nuclear fuel were blown out of the reactors "up to one mile from the units," and then simply bulldozed over to protect workers on site, according to the NRC report
...
U.S. engineers now worry that the enormous amount of water is actually weakening the containment vessels, making them more vulnerable to possible ruptures

Japan Nuclear Plant Is Far From Stable: U.S. Report

Fukushima: A Nuclear Threat to Japan, the U.S. and the World

 

[elbows]

Thanks for the links. I sure wish I could see the NRC report for myself.

Here is the NYTimes article that is the public source for the info in the NRC report, there is a bit more detail but still not enough:

http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html?_r=1&hp

I cant claim that this stuff makes me feel like things are getting worse, simply because I already presume a lot of these things are bad. I mean lets look again at what we have seen for ourselves.

Reactors:

Unit 1's building does not look all that bad really, but we saw an explosion, and the reactor data thats been published hints that perhaps the core is in a right mess there, and the NRC mentions bad restrictions in the ability of water to flow through the reactor core. (although this may have been somewhat improved by switching to fresh water). The latest data I saw continued to show one reactor pressure reading reaching silly levels, and this is also the reactor where they are doing the nitrogen injetion to prevent hydrogen explosions first.

Unit 2 didnt give us much in the way of visual clues as to its state, but it has been the source of scary news about suppression chamber failure, and more recently has given us much news of exceedingly contaminated water. Reactor data is most notable for showing the lack of pressure at various places in the reactor.

Unit 3 gave us the most 'impressive' explosion, photos and video of the building show it to be in awful shape, and sometimes some very dodgy smoke has emerged from this building. MOX fuel automatically ratchets up the concern levels, whether justified or not. Like reactor 2, reactor data is mostly notable for the low pressure readings.

Fuel Pools:

We have heard precious little about Unit 1's fuel pool, and its impossible to judge whether this is a good sign or a bad sign. A reading for the level of water at this fuelpool has been available since around 27th of march, and if its at all accurate then the water level is extremely stable there, but no temperature data is available. Maybe this pool is fine, at least compared to the others.

Unit 2's fuel pool is also something we havent heard too much about, and as with unit 1 the relative lack of apparent building damage at the level where the fuel pool likely is may be an indicator that its not in too bad a shape, but its not safe to assume this with a great degree of certainty. Water level data has been available since 26th of march and its been quite a bit higher than levels at unit 1,but it fluctuates a lot more. Temperature data has been available since 21st march and its also fluctuated a lot, and is likely a fair bit igher than they would like, at anything from 46 to 72 degrees C, even getting as low as 28 degrees C once, but generally on the high side of that range recently.

Unit 3's building looks like such a mess that I worry about its fuel pool. Its hard to see much on photos because of all the mangled building debris, but it could be bad. I dont think any water level or temperature data has been made available at all, apart from maybe once or twice when they were using heat detection equipment on overhead drones or helicopters to estimate how various reactors and fuel pools were doing, and that was quite some time ago now. Given the various smokey emissions from reactor 3 at various times, and the attention they have paid to spraying the pool area of this building on many days, we may further be forgiven for assuming the worst about this one, but I've seen no useful estimates of the state this pool is thought to be in.

Unit 4's pool gets most of the attention because it is pretty safely presumed that this pool caused the explosion at unit 4. I dont think we got to see footage of this explosion, but subsequent photos and video show that the building is a fair mess. Of all the different reactors & pools where we havent been given much detailed info about the state of things, I think this one pisses me off the most. I can see why it can be hard for them to actually go and see whats happening at the various reactors, and unit 4's pool is clearly bad enough that they couldnt get real close to it. But they have paid a lot of attention to dealing with this pool, they have lots of footage of it, there were contradictions between public statements by US officials and Japanese ones in terms of whether there was any water in the pool at all at one point. For a while there were temperature readings but they havent been available for many days now. There are water level readings which suggest that maybe it does still resemble a pool. although I wouldnt bet my life on it. And I get annoyed when I look at photos and video because some people with certain knowledge should actually be able to pinpoint the height and location of the pool relative to the walls of the building, and could judge whether any of the damage lower down some parts of the walls of reactor 4 matches the fuel pool location and hints at bad damage. But I've not seen any such analysis, rather there are some people who should know what they are talking about and go on about the green crane, but as mentioned in a previous post Im not sure they have actually got it right at all. eg has the crane actually fallen from where it is supposed to be? Im not sure that it has, but a proper scale drawing of the reactor ought to make it possible to find out relatively easily, if only this info was readily available.

 

[nick h.]

I know this is hardly a constructive or sensible question - but if the worst case scenario comes to pass, what might the effects be in Japan and around the world?

 

[Dr Jon]

Nuclear crisis man-made

Kojiro Irikura, an honorary professor of seismology at Kyoto University who was on the committee drawing up quake resistance guidelines for nuclear plants in September 2006, said that the Fukushima plant lacked effective "multiple protections" at some key facilities.

Another committee member and nuclear plant expert, Kunihiko Takeda of Chubu University, criticized the government for not demanding that power companies be prepared for natural disasters, in particular tsunami like the massive waves that knocked out the critical cooling systems at three of the six nuclear reactors at the No. 1 plant

Which resonates with my earlier comments.

I know this is hardly a constructive or sensible question - but if the worst case scenario comes to pass, what might the effects be in Japan and around the world?

I said in this post:

Chernobyl involved 1 reactor and 150 tonnes of Uranium.
Here we have 4 reactors and nearly 1200 tonnes of Uranium, Plutonium and who knows what.

So a rough guess at the worst case, based on the tonnage of radioactive material involved, would be Chernobyl x 8.

I also see from this report that other nuclear power plants are susceptible to similar problems in the event of prolonged power outages:

The SOARCA program, which the agency initiated in 2006, focused on two plants: Surry in Virginia and Peach Bottom in Pennsylvania. Coincidentally, Peach Bottom is a Mark I boiling water reactor (BWR) like Fukushima Daiichi reactors 1 through 4.

One of the hypothetical accidents that the SOARCA program analyzed was a station blackout at Peach Bottom where the plant failed to recover power before the backup batteries ran out—the very situation that occurred at Fukushima. That analysis would be extremely useful to understand what happened at Fukushima. However, the NRC has withheld nearly all documents related to SOARCA from the public.

"Don't worry, it can't happen here, blah, blah...."

 

[Dr Jon]

Latest report from Arnie Gundersen:
Closing Ranks: The NRC, the Nuclear Industry, and TEPCo. Are Limiting the Flow of Information

 

[ATOMIC SUPLEX]

There is certaily no panic here in Tokyo despite the constant updates. Its almost as if most people have accepted / gotten bored of it. The people who ran away have come back.

 

[elbows]

Cryptome have some new pics:

http://cryptome.org/eyeball/daiichi-npp4/daiichi-photos4.htm

The last few pictures certainly seem to confirm my previous thoughts on Arnie Gundersons video about 'these boxes are the fuel racks' - the video did not show fuel racks at all, he was wrong. The little boxes were actually part of the green cranes railings. I may be wrong, but have a look for yourself and tell me what you think.

 

[elbows]

Confirmation that the suspicions some have had for weeks now are shared by the powers that be:

http://www.nytimes.com/2011/04/07/world/asia/07japan.html

WASHINGTON — The United States Nuclear Regulatory Commission said Wednesday that some of the core of a stricken Japanese reactor had probably leaked from its steel pressure vessel into the bottom of the containment structure, implying that the damage was even worse than previously thought.

The Nuclear Regulatory Commission’s statement regarded unit No. 2, and the agency underscored that its interpretation was speculative and based on high radiation readings that Tokyo Electric had found in the lower part of unit No. 2’s primary containment structure, called the drywell. The statement said that the commission “does not believe that the reactor vessel has given way, and we do believe practically all of the core remains in the vessel.”

 

[elbows]

Regarding the NRC stuff, here is the congressmans website which includes links to copies of a few emails from the NRC.

http://markey.house.gov/index.php?option=com_content&task=view&id=4293&Itemid=176

Based on radiation readings in the drywell and the torus (3340 rem/hour and 91 rem/hour, respectively), the NRC staff speculates that part of the Unit 2 core may be out of the reactor pressure vessel and may be in the lower space of the drywell. Lower radiation readings in the torus suggest that there is not core material in the torus.

I find that very interesting, not least because I have been asking for some time what the high radiation dose readings at unit 1's torus(suppression chamber) might mean. Using the logic they have employed to describe the possible situation at reactor 2, I could conclude that the high radiation levels in unit 1s torus may mean that part of the core of unit 1 has gone into the torus?

 

[xes]

Cryptome have some new pics:

http://cryptome.org/eyeball/daiichi-npp4/daiichi-photos4.htm

The last few pictures certainly seem to confirm my previous thoughts on Arnie Gundersons video about 'these boxes are the fuel racks' - the video did not show fuel racks at all, he was wrong. The little boxes were actually part of the green cranes railings. I may be wrong, but have a look for yourself and tell me what you think.

Not sure what I'm looking at, but that barge has a footy field on it, by the looks of things. Also, did I get cancer by looking at the pics with the dudes in the chem suits?

 

[Greebo]

That (moving back to somewhere which might not be safe to stay longterm) is IMHO to be expected. Okay, so you've got an increased probability of getting cancer (of some type or other), but so what? You're going to die of something and better cancer than, say, Alzheimer's.

In theory you could move away, and start again, but moving far away enough to get just a bit safer is expensive, and anyway it's hard to leave all your friends, family & memories behind. So, for a lot of people, staying more or less where they are is going to be easier.

Did I mention that human beings aren't terribly good at assessing risk to themselves?

 

[Dr Jon]

Cryptome have some new pics:
...

They also have that NRC report. (PDF)

There's a good collection of expert analysis from The Bulletin of the Atomic Scientists

 

[elbows]

They also have that NRC report. (PDF)

There's a good collection of expert analysis from The Bulletin of the Atomic Scientists

Thanks, I was hoping they would get hold of that document and release it. It wasnt quite as detailed as I had hoped, but interesting anyway.

As for the Bulletin of the Atomic Scientists, any article in particular you recommend? The titles dont inspire me all that much, gives the impression it covers important but dull stuff with an emphasis on learning the lessons for the future, and Im more interested in the exact state of the reactors & fuel pools right now, any ideas?

 

[elbows]

Latest report from Arnie Gundersen:
Closing Ranks: The NRC, the Nuclear Industry, and TEPCo. Are Limiting the Flow of Information

A very interesting video. But Im getting a bit annoyed with a small portion of the stuff he says. He is a good communicator, but why is he saying in this video that 'the NRC believes that plutonium was ejected several miles away from the reactor'? Thats not what they said in this document. They said that fuel particulates may have been ejected from pools 3 or 4, based on things such as neutron emitters found up to 1 mile from the unit. So they arent mentioning plutonium by name, 1 mile is not several miles, and they arent actually making any claims as to exactly how far the fuel may have been ejected, only that they have evidence for it up to 1 mile away so far. These may be relatively minor differences, but it still means I have to go and double-check the sources for everything he says, which rather defeats the point of having someone who can explain the detail in a clear way, if they arent being completely accurate when relaying such detail then their use to me is diminished.

 

[elbows]

I hope the new earthquake does not end up causing problems at another nuclear plant:

Onagawa nuclear plant loses part of outside power
Japan's nuclear agency says the quake on Thursday night disabled 2 out of the 3 outside power lines used at the Onagawa nuclear power plant in Miyagi Prefecture.

The Nuclear and Industrial Safety Agency says the plant has been using outside power lines to cool its nuclear fuel rods since the March 11th quake. The agency says after Thursday's quake, the plant is using only one remaining power line.

The agency says there is no change in radiation levels around the plant as of just after midnight Thursday. The agency is trying to confirm the current status at the plant.
Friday, April 08, 2011 01:30 +0900 (JST)

http://www3.nhk.or.jp/daily/english/08_04.html

 

[elbows]

The latest IAEA update includes info on various nuclear facilities in Japan in light of the earthquake that happened some hours ago. I had previously read a computer-translated version of the press release from the Japanese authorities that included exactly the same information, but I was not going to post anything about it until I'd seen a proper enligh translation:

Fukushima Daiichi Nuclear Power Plant
NISA confirms that no changes have been observed at the on-site radiation monitoring posts. The injection of water into the reactor pressure vessels of Units 1, 2 and 3 was not interrupted.

Fukushima Daini Nuclear Power Plant
NISA confirms that no changes have been observed of the readings at the on-site radiation monitoring posts.

Onagawa Nuclear Power Plant
All reactors have been in cold shutdown since the 11 March earthquake.

NISA has confirmed that two out of the three lines supplying off-site power to the site were lost following the 7 April earthquake. Off-site power continues to be supplied through the third line.

Cooling of the spent fuel pool was temporarily lost, but has subsequently been restored.

No change has been observed in the readings from the on-site radiation monitoring post. The status of the plant is currently being checked.

Tokai Daini Nuclear Power Plant
Tokai Daini nuclear power plant remains in cold shutdown since the 11 March earthquake. No abnormality has been observed.

Higashidori Nuclear Power Plant
NISA has confirmed that the Higashidori NPP was shutdown and in a maintenance outage at the time of the 7 April earthquake. Off-site power has been lost. Emergency power supply to the site is operating. All the fuel had been removed from the reactor core and stored in the spent fuel pool. Cooling of the spent fuel pool is operational.

Tomari Nuclear Power Plant (in Hokkaido)
At the time of the 7 April earthquake Tomari Unit 1 and Unit 2 were in operation. Following the 7 April earthquake, the Hokkaido Electric Power Company reduced the generating power to 90% of capacity.

Rokkasho Reprocessing Plant
NISA confirms that Rokkasho Reprocessing Plant and uranium enrichment facility lost off-site power. Emergency power supply to the site is operating.

Taken from the 17:30 UTC April 7th update thats available here: http://www.iaea.org/newscenter/news/tsunamiupdate01.html

 

[elbows]

I found this article about how many cancer deaths Chernobyl may really have caused to be very informative:

http://allthingsnuclear.org/post/4406180702/how-many-cancers-did-chernobyl-really-cause

I've no way to know if they've got this right but for those looking for some hint as to the scale of radiation-related illnesses and deaths its a start.

 

[elbows]

An old film about Fukushima which is visually interesting in many places and also gives some sense of the scale and complexity of a nuclear reactor, especially the footage filmed during its construction.

 

[story]

elbows, when they get round to making the inevitable documentary about all this, they'll only have to look at this thread to get all the pointers and sources they need.

Whenever I talk to anyone about it, I seem to be far better informed and also less panicked than others, and that's cos I've been getting almost all my info from this thread.

Many thanks to all, most especially elbows.

 

[elbows]

Cheers

Report on what happened at some of the other nuclear facilities in Japan as a result of yesterdays quake:

http://english.kyodonews.jp/news/2011/04/84063.html

Radioactive water spilled from pools holding spent nuclear fuel rods at the Onagawa power plant in Miyagi Prefecture following the strong earthquake late Thursday, the nuclear safety agency said Friday.

At the crisis-hit Fukushima Daiichi nuclear power plant or at another plant in Fukushima Prefecture, meanwhile, no new problems have surfaced since the magnitude 7.1 aftershock of the deadly March 11 quake.

While the spent fuel pools at the Onagawa plant and the Higashidori nuclear power station in Aomori Prefecture, both operated by Tohoku Electric Power Co., lost their cooling functions for 20 to 80 minutes after the quake, the temperature hardly rose, the Nuclear and Industrial Safety Agency said.

A small amount of contaminated water spilled on the floor was observed inside the buildings at all three reactors at the Onagawa plant, which has suspended operations since the mega earthquake and tsunami last month, according to the agency.

In all, water spilled or leaked at eight sections of the plant as a result of the 11:32 p.m. quake, according to Tohoku Electric.

More info in the full story, sounds like some of the locations got grid power back overnight.

A video of someone driving round inside the exclusion zone:

 

[elbows]

The latest reactor data, only available in Japanese so far, shows pressure still rising from one reading inside reactor 1. And the CAMS monitoring system that shows dose rate inside the drywell of unit 1 has risen hugely sometime between midday on the 7th (where it was 31.7Sv/h) to a staggering 100Sv/h at midnight on the 8th. Dose rate in the torus has decreased very slightly in the same time period, as it has been doing on and off for a while now.

 

[laptop]

I found this article about how many cancer deaths Chernobyl may really have caused to be very informative:

http://allthingsnuclear.org/post/4406180702/how-many-cancers-did-chernobyl-really-cause

I've no way to know if they've got this right but for those looking for some hint as to the scale of radiation-related illnesses and deaths its a start.

I've not checked the arithmetic, or looked for other estimates of radiation dose/response: but that looks like a very reasonable. non-alarmist estimate.

The lowest estimates are obtained by looking only at the most highly exposed people. This shows why that's cheating:

Other very low estimates out there assume that below some threshhold dose radiation has no effect, or event (to confuse things) that very low doses prevent cancer. (Paging Jazzz... no, new thread for that.)

Some of the higher estimates are based on the suggestion by Bertell et al that radiation causes increases in non-cancer diseases, the evidence for which is, er, sparse.