Sunday, March 13, 2011

For Those Concerned About the Japanese Nuclear Reactors

Update: More updates and links at Brave New Climate

Brave New Climate has a number of posts that explain the situation

Josef Oehmen on the situation

I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
Barry Brook on the situation earlier

Here is a précis of the situation as I understand it:

1. There is no credible risk of a serious accident. All reactors responded by insertion of control rods to shut down their nuclear reactions. Thus, power levels in all cases dropped quickly to about 5% of maximum output, and the nuclear chain reaction ceased (i.e., all units are subcritical).

Note: I judge the situation would currently be rated INES Level 4: Accident with local consequences on the international nuclear event scale. Update: This level has been confirmed by WNN (5:50 GMT).

2. The concern is providing emergency cooling water to the reactor cores to remove decay heat from the fuel rods. This residual heat comes from the fission products, and will be persistent, but diminishes rapidly over time (i.e., most decay heat occurs over minutes and hours, with cold shutdown within a few days).

3. At one plant, the 40-year old Fukushima Daiichi (unit #1 opened in 1971), the backup diesel generators supply power to the core cooling system failed (apparently due to damage from the tsunami). This allowed pressure to build up in at least one of the reactors cores to about 50% higher than normal (unit 1), and requires venting of very mildly radioactive steam (contains trace levels of tritium). Some discussion here.

Eli recommends you go there and read.

197 comments:

Neven said...

Here is a précis

Shouldn't that be a 'praisee'?

No Win No Fee said...

I keep hearing the word meltdown more and more in the news...

jyyh said...

yes, the reporting is quite inaccurate. f.e. been hearing of exposed/non-exposed MOX/regular rods/cores in 1/2/3 reactors and anyway Fukushima 1 insides are not in a pretty shape after that explosion with 1tn reinforced concrete slabs flying for 100m. but the upside is it will be noticed in pacific isles (or where the wind blows) if this is downplayed.

Steve Bloom said...

As someone with a relevant background, when I first heard "meltdown" being flung about I thought of rather worse circumstances than the ones that prevail.

Eli, note that in these circumstances there's a big, big difference betwwen new fuel and old fuel. There's a reason why spent fuel rods have to be cooled continually. If one of those reactors has an older core that even at this late date goes uncovered for a few hours (maybe less, maybe more, depending on core age, and a relatively fresh core indeed may be out or nearly out of the woods by now), that's trouble in Sendai city, and I mean with a capital T (well, S, but the important thing is how you get the answer).

Bear in mind also that the nuclear industry is very PR-conscious everywhere it exists (some, not me, but perhaps Eli, might say prone to cover-ups) and that we're talking Japan here, a culture wherein the careful avoidance of public embarrassment is a fine art.

Steve Bloom said...

This from the Beeb just now causes me to wonder where exactly the hydrogen for the explosion came from if there's no vessel breach:

"A second explosion has hit the nuclear plant in Japan which was damaged in Friday's earthquake, but officials said it had resisted the blast.

"TV footage showed smoke rising from Fukushima plant's reactor 3, a day after an explosion hit reactor 1.

"Japan's nuclear safety agency said the blast was believed to have been caused by the build-up of hydrogen.

"However, the agency said it could not confirm whether there had been an uncontrolled leak of radioactivity."

Something sounds fishy.

Steve Bloom said...

Via a comment at BNC, video of the recent explosion. Not so small. Probably still not a spot on a vessel, but the pipe connections are rather more delicate. And that hydrogen got into the containment from *somewhere*.

David B. Benson said...

I think I answered for myself all the explict and implict questions in prior comments. This was accomplished by reading all three of the Sendai threads on Brave New Climate.

John said...

Here's a good article from Thomas Maugh of the Los Angeles Times. We have been very critical of reporters for their coverage of global warming. Now it's time to give credit to a reporter who does a good job.

Marion Delgado said...

Screw that. They're insane shills for nukes, and always have been.

pointer said...

That L.A. Times article was extremely good. I read through the Brave New Climate piece and thought it was too cheery. And there's been some meaningful pushback in the BNC thread on the piece. See especially the "debunking" at http://tinyurl.com/69bykgd. I am a little concerned that the blogger at BNC completely minimises the role of renewables in forming a climate-change solution elsewhere on his site. It's all nuclear, as far as he's concerned. Even if you're not anti-nukes, that's a strong opinion requiring strong evidence.

At this point, there are so many unknowns, it's hard avoiding getting slapped around by all the competing agendas in the blogosphere.

Neven said...

My problem with nuclear (and the BNC blog by extension) is:

a) the centralized power generation aspect of it. I'm more a fan of decentralized power, literally and figuratively speaking.
b) the idea that we must keep powering society as it currently is, very wasteful, centred around an economy that must grow forever.
c) Jevons paradox.

And oh yeah, sometimes something awful happens, like a huge earthquake+tsunami or a terrorist attack, making nuclear power very expensive. But this isn't even my main objection. Small fast breeder reactors which can be developed quickly? Sure, why not?

With regards to the situation in Japan, official statements and press coverage: after having recently translated a French documentary on the 10 biggest environmental disasters ever and the way press, corporations and politicians handled those (such as Chernobyl of course and Minamata, to name a Japanese example; let's not forget the BP oil spill) makes me extremely wary.

Either way, it is impossible to tell if this incident is a nuclear disaster or not (for now). But nuclear opponents and proponents are showing their flying colours nevertheless, which is interesting to watch in itself.

Martin Vermeer said...

The LA Times article was OK, but already the lede shows up another journalistic malpractice:

They are pumping seawater laced with boron, to absorb radioactive emissions,

No my friend. Boron absorbs neutrons. Who wrote the lede (the article itself is correct on this)?

Sigh.

Marion Delgado said...

Martin Vermeer, how is that journalistic malpractice? Neutrons are radioactive emission.

Marion Delgado said...

Eli, why on Earth are you pushing these bastards? What, exactly, is this "But you will know more about nuclear power plants after reading it than all journalists on this planet put together." contributing, again?

Marion Delgado said...

Finally, "Update: This level has been confirmed by WNN (5:50 GMT)." - confirmed by the World Nuclear Association (that's what the WNN is)? Why wouldn't a nuclear industry association - and that's all that it is - confirm the most optimistic reports and evaluations?

http://www.sourcewatch.org/index.php?title=World_Nuclear_Association#Articles_and_resources

This is churnalism pure and simple - press releases from the nuclear power industry passed off as news.

J Bowers said...

Oehmen's piece is receiving a lot of flak with a number of supposed errors being pointed out. If his dad had written the article that would have been better, but I'm afraid it's getting precisely the criticism that I, for one, dole out to denialists and their "experts".

@ Steve Bloom. The hydrogen coolant for the turbine stators has been suggested here and there, as the source of hydrogen.

Anonymous said...

Martin, I thought (perhaps erroneously it seems) that neutron emission was classed as radioactive decay, since the (fast) neutron has the potential to ionise a target material.

Cymraeg llygoden

J Bowers said...

Sir John Beddington was just interviewed on BBC news, and an expert panel (nuclear experts, academics, etc) that he arranged over the weekend concluded that even if a worst case scenario occurred it would be absolutely nothing resembling Chernobyl, with any radiation release lasting roughly an hour reaching around 500 metres up. Chernobyl lasted weeks or months, and reached tens of thousands of metres into the air.

(copied from wrong thread)

Tim Worstall said...

And that hydrogen got into the containment from *somewhere*.

Sure, Fred Hoyle was wrong, it doesn't simply pop into existence.

That "where" would be from inside the reactor though. Water level falls, hot Zr plus water gives you H2 and O. As the pressure rises, you vent some of this. Giving a little boost in radiation (mainly N16 which decays to O16 in about 5 seconds) and a tiny tad of contaminants outside the containment vessel.

If you vent directly to atmosphere you get that radiation outside: if into the gap between the two buildings, the H2 builds up and can explode. You then of course get radiation outside but not so much. And maybe it won't explode?

BTW, the reported radiation levels just as Fukushima 1 went bang were of the level of a 20 banana a day habit for a year. And fell rapidly (that N16 thing).

Anonymous said...

I don't know what Oehmen means by 'under control'. The last I heard 2 nuclear reactors have been destroyed. Sea water is being pumped into them. The U.S. has flown in emergency supplies of 'coolant'. I assume that means boric acid to 'cool' the nuclear reactions, not water to quench the heat, and also absorb neutrons. The Japanese government has reported significant amounts of radiation being released. Some people have been hospitalized.

The second reactor exploded a couple of hours. While this is an ordinary physical exploded, and a nuclear explosion is not a possibility, the Japanese have been hoping like hell to avoid it.

There was a lot of talk on the cited web pages above about 'risk assessment' and why was this high for nuclear plants. Nobody seemed to know why. The reason is because a nuclear power plant that becomes unusable is a loss of ~$1billion. New nuclear power plants have not been built in the U.S. since 3 Mile Island. Previously the bankers had been told that the risk of a nuclear plant accident was 1 in 10 million years.

When the banks found out that the risk of accident to $1billion was considerably higher, they lost interest in nuclear power. Now the U. S. government has promised to guarantee the loans and to also pick up any incidental costs for an accident, like blowing radiation all over the East Coast. (Which didn't happen at 3 mile Island because a technician randomly or accidentally pushed in water about 10 minutes before 'meltdown'.)
If I'm way in error on this, I'd like to be corrected. As it is, I think there's little prospect for more nuclear power in the near future. I think the huge subsidies we've given nukes for 50 years are enough; I don't want more taxpayer money dumped into. When we don't even have a place to put the spent fuel rods. They are in 'your back yard'.

Snow Bunny

badger badger badger said...

Could the H2 be coming from coolant water being broken up by radiation? A couple of careers ago working with cyclotrons I had to bleed that off from the water cooling lines.

Anonymous said...

The brave new climate article is helpful, but not without it's own problems. Most importantly, the Fukushima reactors do not appear to have core catchers. This is apparent from the figures. (Indeed, they don't seem to have been invented till the late 70's, although a retrofit is not totally impossible.)

That makes keeping the core within the pressure vessel rather more important.

Martin Vermeer said...

Marion, fast neutrons are weakly ionizing (mainly, by bumping protons which are strongly ionizing) and decay within fifteen minutes, but that was not the reason boron was used. So, generalizing to 'radiactive emissions' was grossly misleading: boron isn't even effective against any other forms of radiation...

The article text gets it right. Seems that those that can, write articles, those that cannot, ledes :-(

Neven said...

Eli, I think your spam filter got my carrot. It wasn't the best thing I have ever written, so you could leave it there. I just thought I'd share my opinion on nuclear power with the world and express my interest at how everyone is showing their nuclear colours.

badger badger badger said...

Marion's got it right. BNC looks like a nuke PR site with AGW as a sideline/rationalization. And events have already passed by the warm-and-fuzzy-bunny posts linked.

Chenobyl it ain't, but jeez.

Anonymous said...

Snow Bunny says:

Nothing is "under control" in the Japanese nuclear plants. 2, now 3, power plants are toast. You don't dump sea water on a reactor if things are under control. Radiation has been released, some U.S. Navy men are being treated.

The site you refer to is an elementary description of a power plant. Obviously the participants aren't full of knowledge. Nobody could answer Hank Robert's question why was 'coolant' being flown in by the U.S. Coolant in this context is neutron absorbing material to decrease nuclear reactions, probably boric acid. Obviously nobody is flying in water when the sea is a few feet away.

The nuclear power industry has suffered a massive setback (Switzerland just put all its plant approvals on hold, for example.) Expect oodles of 'think pieces' proving nuclear is as cuddly as a panda bear.

Anonymous said...

It's all provisional of course, but here is what looks like the latest TEPCO update on the Japanese reactor situations (courtesy of Barry's BNC):

http://www.jaif.or.jp/english/news/2011/110314fukushima_event-status-1.pdf

Cymraeg llygoden

J Bowers said...

As far as I've read, the radiation dosage for those affected is equivalent to eating 20 bananas a day for a year. A pricked finger gets written into the First Aid log just as much as a decapitation.

The Guardian had a live Q&A qith some experts today. It's worth a read of the comments for their responses to questions. For instance...

"profgerrythomas
14 March 2011 1:43PM
@dawnmacbean
Yes individuals do react to radiation in different ways. Would you refuse to have an X-ray (dental or otherwise) or a CT scan? We all expose ourselves to radiation for medical purposes - in reality the amount of radiation that has currently been released is lower than what we use for medical purposes. There is no conspiracy here - the facts are the facts.

profgerrythomas
14 March 2011 1:57PM
@assaultedpeanut
There has been very little release of radiation and there is unlikely to be a significant release. My advice would be not to worry. You are lucky because in Japan you eat a diet that is rich in iodine - this would protect you from the worst possible effects. I would not advise you to do anything further unless instructed by your government or medical authorities. I am afraid there is far too much scaremongering!"

http://www.guardian.co.uk/environment/blog/2011/mar/14/nuclearpower-natural-disasters

J Bowers said...

Tim Worstall has a post up:

http://timworstall.com/2011/03/14/the-guardian-editorial-using-fukushima-to-tell-us-all-how-dangerous-nuclear-is/

He concludes...

"So, we’ve just had the fifth worst earthquake in the past century, the 7th worst we have on record, a 30 foot wall of water sweeping in at 500 miles an hour and the worst part of the nuclear power system is that if you were standing right there, right at the plant, you might get the same radiation dose as a fruitarian?

And you want to use this to tell us that nuclear power is dangerous?

I’ve got bells on the other one which will jingle if you pull it."

dhogaza said...

Martin Veemer:

"The article text gets it right. Seems that those that can, write articles, those that cannot, ledes :-("

Google "copy editor". Who do you think misspelled "lead" in the first place? :) :)

dhogaza said...

Tim Worstall:

"That "where" would be from inside the reactor though. Water level falls, hot Zr plus water gives you H2 and O. As the pressure rises, you vent some of this."

Your story is more or less what the NYTimes was reporting. Pump in sea water, it's hot enough to boil off, there's hydrogen being generated by the core (though they mentioned the fuel pellets cracking from the heating after being uncovered for a period) and this along with steam was released into the building surrounding the containment vessel when the containment vessel was vented due to high pressure, where it mixed with oxygen and was set off by some source and blew the top off of the main building (which isn't meant to be any sort of containment structure).

dhogaza said...

jyyh:

"yes, the reporting is quite inaccurate. f.e. been hearing of exposed/non-exposed MOX/regular rods/cores in 1/2/3 reactors and anyway Fukushima 1 insides are not in a pretty shape after that explosion with 1tn reinforced concrete slabs flying for 100m."

The reporting seems fairly accurate, as I've been seeing direct quotes from the operating company, government officials, etc that reflect exactly the same confusion as is being reported. It's pretty obvious it's not clear what's going on inside the worst reactor, at least, and apparently there's confusion over the term "partial melt-down" as well (the NYTimes today reported on two different definitions being used, though it's not clear that the more generic definition is actually used in the industry, or only in popular usage).

Also it's been reported today that one valve used to flood the worst reactor broke earlier Monday Japan time, and that it took some hours to repair it, and during that period of time they were unable to introduce more seawater into the containment vessel, leading to more fuel pellets being uncovered as the water in the vessel boiled off (leading to more venting of the containment vessel, presumably).

I think it's obvious that it's not going to be another Chernobyl - these reactors have proper containment vessels, at least. But the worst-off reactor might well be another TMI, and it's not out of the question that all three will be. In other words ... expensive, but not deadly.

dhogaza said...

This, from Reuters, seems reasonable.

silence said...

So it looks like things were worse than previously announced:
> The plant’s operator, Tokyo Electric Power, said late
> Monday that repeated efforts to inject seawater into
> the reactor had failed, causing water levels inside
> the reactor’s containment vessel to fall and exposing
> its fuel rods. After what at first appeared to be a
> successful bid to refill the vessel, water levels again
> dwindled, this time to critical levels, exposing the
> rods almost completely, company executives said.

Without cooling, the containment vessel won't contain, and:
> The more time that passes with fuel rods uncovered by
> water and the pressure inside the containment vessel
> unvented, the greater the risk that the containment
> vessel will crack or explode, creating a potentially
> catastrophic release of radioactive material into the
> atmosphere
Given the way the nuclear industry lies, this kind of announcement means that a large-scale release of radiation is very likely in the near future.

Anonymous said...

the nuclear fuel rods are covered with zirconium cladding. When temperatures become hot, the zirconium catches fire and oxidizes, taking the oxygen from water or steam and releasing H2 to venting.

The hydrogen comes from water.

Many other nasty things happen as the core melts more. Radioactive caesium has been detected some distance away by now.

Snow Bunny
http://www.nap.edu/openbook.php?record_id=11263&page=39

seamus said...

jyyh, the top section of these buildings are sheet metal, not concrete, and are not part of the containment.

Snow Bunny: "Radiation has been released, some U.S. Navy men are being treated." So far, small amounts of low-level radiation have been released. Apparently not enough to cause serious health concerns.

I agree that BNC has been working a little too hard to downplay the seriousness of this event. But jebus, look at some of the media outlets, giving a totally fact-check-free platform for supposed "nuclear experts" and their agenda.

It's too bad there's so much irrational fear of nuclear energy. Maybe if there was a less hysterical reaction to TMI for instance, we might have already made some progress in rolling out new reactor designs with built-in passive safety. That is, designs where there's no chance of overheating even if, as in the 40-year-old Fukushima units, the coolant pumps are disabled.

Renewables are awesome, but there's no way they can provide nearly enough electricity for increasing population and growing demand.

Generation IV reactors

How do fast breeder reactors differ from regular nuclear power plants?

(I am an independent-minded, concerned lay person. Concerned about climate disruption and what that will do to our biosphere and our society. I have no connections to any energy companies or related organizations. Politically, I'm a die-hard moderate.)

Steve Bloom said...

dhogaza, worse things very much can still happen. The age of those cores may make all the difference. That there's control of the venting is good, but no panacea given all the other variables. Having too vent at all is trouble, since too much of it will uncover the top of the core. Not enough and there's the prospect of a hydrogen explosion inside a vessel. The vessel itself would probably survive that but the weak points (piping connections) would not.

The worst-case here is that partial melting of the rods concentrates the fuel and blocks the flow of coolant sufficiently such that fissioning initiates. Such an event can occur relatively slowly (or quickly if an explosion results in a catastrophic loss of coolant flow), so given that the cooling is being kludged and core damage (i.e. some degree of melting) has already been admitted to for at least one reactor, this situation is far from out of the woods. The many "it's just waste heat, so no problem" comments from overly sanguine folks are simply ignorant. If the cores are new they'll very likely be right, but as far as I can see that information hasn't been made available.

MOX, BTW, means that the rods contain plutonium, which is the way in which a meltdown at one of these reactors has the potential to do damage on the scale of Chernobyl.

No charge for the free reality, Tim.

J Bowers said...

Chris Mooney has his own take, over at DeSmog:

'Are Liberals Science Deniers? Now’s A Good Time to Find Out'

http://www.desmogblog.com/are-liberals-science-deniers-now%E2%80%99s-good-time-find-out

seamus said...

And I live about 50km from a nuclear power plant.

dhogaza said...

Steve Bloom:

"Having too vent at all is trouble, since too much of it will uncover the top of the core. Not enough and there's the prospect of a hydrogen explosion inside a vessel."

My understanding is this is one reason they've been venting, to lower the amount of hydrogen in the vessel (along with lower steam pressure). My guess is that the managers trying to control this thing weren't particularly surprised to see the non-containment building around the containment vessel get its top blown off. Looks spectacular but isn't particularly important ...

"MOX, BTW, means that the rods contain plutonium, which is the way in which a meltdown at one of these reactors has the potential to do damage on the scale of Chernobyl."

Steam explosion when it drops to the bottom of the vessel which has been collecting water?

The control rods are all in so wouldn't the fuel have to melt or otherwise drop down below the control rods for fissioning to start up again?

This is an example of official announcements that either add to the confuse, or indicate that the TEPCO's not been entirely clear:

'"A top Japanese official said the fuel rods in all three of the operational reactors at the Fukushima Dai-ichi plant appeared to be melting.

"Although we cannot directly check it, it's highly likely happening," Chief Cabinet Secretary Yukio Edano told reporters.'

J Bowers said...

Strangely enough, I'm starting to see comments around and about from previously anti-nuclear bods who've been so impressed with the way these ageing plants (Fukushima is older than Chernobyl) have held up after the worst that nature could throw at them, they've become pro-nuclear (with the caveat that the waste is dealt with sufficiently).

Steve Bloom said...

Thanks for locating that quote, dhogaza. It underlines the point that there's no very good way to know the condition of the cores. It sounds like they can still track heat and pressure, but how well are those sensors working under these circumstances?

That's correct re the venting.

Re a meltdown, bear in mind that there are voids for water flow in addition to the (presumably filled) rod channels, so melting/collapsing fuel does have a path downward. The point at which significant fissioning can occur is a function of how much of it can collect in one place, but given sufficient time and residual heat enough will collect in the bottom to get the job done. An article I saw said that these reactors lack the kind of China Syndrome failsafe newer ones have, i.e. if the fuel manages to melt through the bottom of the vessel there's pretty much nothing stopping it from reaching ground water (which has to be close given the location). At that point true disaster ensues: Radioactive Pu-laced geysers will find their way to the surface and blow into the atmosphere until there's no longer enough fuel to maintain fission.

I also saw something I once knew but had forgotten, it being 20 years since I paid much attention to this stuff, which is that the MOX fuel is contained in ceramic pellets. The theory is that they won't melt, limiting both the concentration of the fuel and the potential for Pu contamination of the surrounding environment (aka most of southern Honshu), but of course this has not been tested as such. Some fission products being gaseous (IIRC Xe is prominent), at the least there might be quite a bit of splitting up into smaller bits, in turn exposing more Pu. A meltdown would also subject those pellets to thermal and mechanical stress that they don't normally experience. In any event it's a whole lot better than the Pu not being in a ceramic matrix.

Steve Bloom said...

That's interesting, JB. Specifics?

Dallas said...

Eli! Great job an no radio!!

Someone asked about hydrogen exploded, http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V4D-4810XXN-11B&_user=10&_coverDate=11/30/1987&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_searchStrId=1678573355&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=e04eac686e9a3bcdf9038e5a064861f6&searchtype=a It is a product of a partial melt.

Another mentioned nothing was under control because of saltwater. Once there is a partial meltdown , the reactor is toast, so the saltwater is not going to damage anything worst than they are.

Thankfully, people that have a clue are being heard, finally! What has happened was not missed in the design. Without time to bring portable power in because of everything else going on, this was a predictable event.

And no, I am not a nuclear engineer, I stayed at a Holiday Inn Express last night and happen to study stuff that may impact my life.

Anonymous said...

wow! strange to see the rational scientist crowd almost as spooked as the guys at WUWT...

Dallas said...

Steve Bloom, Actually, the guys would have been more impressed if everyone had run away and left it alone. Light Water Reactors may be old, but they were designed for 20 year olds with an average eighth grade education to run them. Even had the control rods not gotten into place to stop the reaction, loss of water, the moderator, would have stopped the reaction. There would have been more melt, but really not much greater consequences.

http://en.wikipedia.org/wiki/Light_water_reactor

Small modular light water reactors, like Navy reactors, have an additional advantage because the mass of reactant is much lower making it much easier to cool in such an event.

Anonymous said...

seamus,

only 50 workers are remaining in reactor 2 after another explosion, they are heroes. They are still trying to cool the reactor core to prevent sever meltdown. The Japanese cabinet minister said people 30 kilometers away should stay indoors now, they said there is a risk to human health.

Reactor # 2's containment of the nuclear core is apparently breached. They were not able The crisis is now categorized as worse than 3 Mile Island. Radioactive by-products including Cesium are detected. This is an indication of fuel rod damage.

I'm still wondering how the blogger Eli referenced could say with a straight face that damaged nuclear reactors were not out of control. It isn't under control until the nuclear chain reactions cease and the core cools down.

Snow Bunny

Steve Bloom said...

Yet another ka-boom a few hours ago, this one bigger and reportedly with significant damage to the vessel (of #2).

Dallas, it is extremely apparent that you're not well-informed about this stuff. Contemplate, if you will, why used reactor fuel rods need continuous cooling in pools after they're removed from reactors. Contemplate also that officials have admitted that there has already been melt damage to some of the fuel, and what the logical end of that process would be. Actually just now the Beeb site is running a nice animation of what it would look like melting and pooling in the bottom, so you don't have to imagine. Speaking of the used fuel rod pools, they're inside the containments (er, former containments), apparently with no means to ascertain their status.

BWRs are a type of LWR, BTW. No type of light water power reactor is immune from these problems. I doubt that heavy water power reactors are either, although I don't know much about them. If cooling is not maintained in a SCRAMmed reactor, trouble ensues, the degree depending on core age. BTW, a big blob of melted fuel is perfectly happy to fission all on its own, although things get much worse if it finds water.

Re Navy reactors (which are not modular, whatever you meant by that), they are indeed a lot smaller. To achieve that, the fuel is basically bomb-grade. They are quite capable of melting down.

See the concise description here, also.

Steve Bloom said...

I'll repeat something I said above:

"Bear in mind also that the nuclear industry is very PR-conscious everywhere it exists (some, not me, but perhaps Eli, might say prone to cover-ups) and that we're talking Japan here, a culture wherein the careful avoidance of public embarrassment is a fine art."

It won't be clear until well after the fact that the worst case has been avoided.

dhogaza said...

Steve Bloom:

"Dallas, it is extremely apparent that you're not well-informed about this stuff. "

Oh, clearly he is, those engineers and skilled workers trying to tame these reactors are risking their lives and being hospitalized trying to do so because they're fucking idiots!

Dallas - you're sliming heroic workers and engineers who are fighting real problems ... Steve Bloom may be educating me to some extent regarding details, but I'm no where near ignorant enough to make the offensive comments you've made.

dhogaza said...

Steve Bloom:

"Re a meltdown, bear in mind that there are voids for water flow in addition to the (presumably filled) rod channels, so melting/collapsing fuel does have a path downward. The point at which significant fissioning can occur is a function of how much of it can collect in one place, but given sufficient time and residual heat enough will collect in the bottom to get the job done."

Thanks for the details, nothing you say contradicts what I've been concluding from the more technical coverage I've seen.

The Q is, of course, whether or not the fuel is melting or heat is causing the core structure to collapse.

And, I admit, each report out of Japan seems more and more pessimistic ...

dhogaza said...

BTW, Steve Bloom, thanks for all the details in your above posts (which I entirely agree with, though my background is less specific than yours).

I still think the containment vessels will win out ... but all three reactors will be huge economic losses (the worst almost certainly a total loss).

But I could be wrong ... I'm trying to be optimistic here :)

(as opposed to dismissive ...)

dhogaza said...

Of course, after posting above:

"High levels of radiation leaked from a crippled nuclear plant in tsunami-ravaged northeastern Japan after a third reactor was rocked by an explosion Tuesday"

Oh, we're up to three hydrogen explosions ...

" and a fourth caught fire in a dramatic escalation of the 4-day-old catastrophe."

Umm ... three were up and three were down, where's number four? One of the down ones? So we've moved from two popped-tops to three, and a fourth on fire???

I'll go read but I'll let y'all update the thread ... :)

dhogaza said...

Well, one more:

" A fourth reactor that was offline caught fire on Tuesday and more radiation was released, Edano said."

Maybe reactor clusters aren't such a good idea, unless you're really, really confident about your siting criteria ...

adelady said...

I think the "fourth-on-fire" was the building with the holding ponds for spent fuel. Fire's out now.

Let's all be grateful for small mercies. The description of what's actually in those holding ponds is not conducive to relaxed good cheer.

MinniesMum

dhogaza said...

adelady:

That's not what I've read:

" A fourth reactor that was shut down caught fire on Tuesday and more radiation was released, Edano said.

The fire was put out. Even though the fourth reactor was shut down, the fire there was believed to be the source of the elevated radiation."

They had three online, three undergoing maintenance (uptimes for reactors, at least older ones, tend to be around the 50% mark).

Holding ponds tend to be outside - after all it doesn't matter if they're rained on ....

adelady said...

dhogaza. As I understand it, these holding ponds are on the third floor (because of the flooding / tsunami risk?). IIRC I picked that up at Joe Romm's but don't sue me if you have to go elsewhere for that info.

And the ABC (Australia's that is) has just reported that no 4 is on fire as of 20 mins ago. Radiation is leaking.

Steve Bloom said...

The pools are indeed inside the outer containment structures (the ones that were seen to blow apart). My understanding also is that the fire was (is?) in one of those, but that the fourth reactor is in cold shutdown (although it still would need coolant circulating, and the "cold" part seems odd unless perhaps it's a very new core). Most of the pools are now out of sight, covered by debris from the collapsed containment ceilings, and I've seen nothing as to their status. Clearly they could be big trouble.

The latest I saw is that they've evacuated most of the workers from the site, leaving just 50. This isn't getting better.

Dhogaza, I hope you're right about the vessels, but one thing I can tell you is that they weren't thinking about this scenario when those things were engineered. Also, it might take a couple days for the fuel to melt through, so I'll be holding my breath until such time as the physical status of the cores can be confirmed or there's a distinct cooling trend that precludes the possibility of a melted core.

pointer said...

I'm no knee-jerk anti-nuke greenie, but what on earth was that damn thing doing so close to the shoreline? I'm travelling to Tokyo next month to settle there long-term, and I am very. VERY. Anxious. Japan better damn well rethink its safety regulations.

Anonymous said...

@pointer

Nuclear power stations need a lot of cooling water. A lot.

Putting it next to the sea is a good idea because there is a lot of water there. If you look at the UK, pretty much all of the nuclear power stations are on the coast (I don't know of any exceptions, actually).

Admittedly, there are no tsunamis in Western Europe, which might conceivably cause problems, while there are in Japan (what with it being a Japanese word and all), but I'm sure that's all been thought through in great detail.
--
Danger Mouse.

adelady said...

Siting these things next to an ocean is a far better option than the rivers commonly used in Europe and the USA. Hot summers in recent years have forced shutdowns of nuclear plants in France and in Tennessee - either because of the water being too warm or because there's too little of it in the remnant trickle left behind in a drought season.

As for Japan, I think familiarity breeds contempt. They're so used to living with constant quakes and their other building regulations are so strict - and successful - that they've convinced themselves they can engineer their way out of anything. As we see, nothing can stop a tsunami from going where it's going.

My personal view is that all major infrastructure that 'needs' seaside or riverside placement will have to be reconsidered or entirely substituted in view of anticipated sea level rise. Stuff that's supposed to have a useful life of 40 or 60+ years should be placed where it won't be drowned, flooded or otherwise wrecked.

Dallas said...

Dyhogaza, I am not sliming emergency workers. There are points in dealing with such an event where allowing time and design take its course is the best procedure. There are levels of containment. Once the first level, the control rod housing (tube if you wish) is breached,the tactics change. For example, diverting relief pressure steam into the exterior containment building to let the radiation reduce before going to atmosphere sounds great. But it leads to hydrogen explosions. Relief is designed to vent to atmosphere for a reason. Another very heroic idea would be to flood the containment building with water to cool the reactor. That can lead to a steam explosion. The thermal mass of the containment building floor is designed to cool the fuel in the event of a pressure containment vessel breach, without producing a steam explosion.

Steve Bloom, " Contemplate, if you will, why used reactor fuel rods need continuous cooling in pools after they're removed from reactors." Have. Water is a moderator, it slows down fast neutrons. There is a low statistical probability that pure water will "react" with the neutrons to produce exotic isotopes. Boron is often added to the storage pool as it also is a moderator not a coolant.

Also fuel for commercial reactors of this type is typically U238 with a percentage between 3 and 10 of U235. Not good bomb making material for a reason. Chances for an explosive chain reaction is nil.

"The fire was put out. Even though the fourth reactor was shut down, the fire there was believed to be the source of the elevated radiation." Of course fire is not the source of the radiation. It does increase the spread of radiation, as does a steam explosion. However, fire would be external to the "real" containment building where the heavier radioactive material is contained. Lighter isotopes, tritium, cesium and iodine vented with pressure relief, are radioactive, but a much less nasty form of radiation. Concentration and type of radiation is needed to evaluate the hazard.

BTW, information on small modular reactors is only a Google search away. Dr. Richard Muller has an interesting discussion on LWR in his physics for future presidents series, which should be mandatory for journalists and evidently some other professions.

J Bowers said...

@ Steve Bloom. Here's one I can find at Grauniad.

I'm not saying it's en masse, mind you, but there have also been a lot of people coming out in defence of nuclear. I must say that I'm finding myself in disagreement with a number of people I'd normally be in agreement with; John Vidal, and Joe Romm to a degree (though he does have a PhD in physics so my bad no doubt), as examples.

If you've ever come across Greg Palast before (one of the best and most thorough investigative journalists as far as I'm concerned), he has a post up based on his direct experience of investigating the nuclear industry for Big Gummint. Not very reassuring. Leads me towards the opinion that all nuclear should be nationalised.

J Bowers said...

Someone's notes on Sir John Beddington's talk with the British Embassy in Tokyo today:

"15 March 2011 10:31AM [GMT]

At around 5 PM Japan time today the UK government’s Chief Scientific officer John Beddington spoke to the British Embassy in Tokyo, and to others listening in on the teleconference, and gave us some information about worst case scenarios at the Fukushima plant.
I made the following notes on what was said and found it very reassuring:

1. Worst case scenario (reactor explodes) problems would only affect a 30 km radius around the plant.
2. No health problems expected outside this 30 km area. Today's reports of increased radiation in Tokyo are trivial. The increase in radiation they are reporting is not significant. It would need to be 100s of times that level to cause any problems.
3. An allowable dose would be 100 times the background radiation.
4. They can monitor radiation levels in the area from outside Japan, so there is no cover up going on. Conspiracy theorists stand down.
5. In Chernobyl the top blew off the reactor and then the core caught fire and burnt. This convection pushed all radioactive material higher and higher into the air where it reached 30,000 feet and so the spread was much larger.
Here, a build up of pressure as the radioactive material interacts with the containment floor would cause an explosion that would only reach as high as around 500 meters. This would contain any dangerous material within the 20 to 30 km exclusion zone.
6. If all attempts at cooling the reactors fail, a worst case scenario, then there would be an explosion, but this blast would only throw radioactive material up to 500 meters, and the 30 km containment zone stands.
7. Acceptable levels of radiation are based on the most susceptible members of society (children and pregnant mothers). So right now, the levels outside the 30 km zone are fine for all members of society.
8. No matter how strong the wind, the radioactive material released after an explosion of the core wouldn't make it to Tokyo.

These are just the main points I picked up, a transcript/podcast will apparently be uploaded to the British Embassy's Japan Web site. It was reassuring to hear a calm but informed perspective."

Anonymous said...

Snow Bunny says:

The Japanese stock market dropped over 10% Tuesday. The nuclear fallout issue, as well as problems with electricity supply.

JMurphy said...

A more recent post on Brave New Climate here, says that should be INES Level 6.

dhogaza said...

Well, Dallas, looks like Steve Bloom's on the mark with his comment regarding spent fuel, since the radiation from the fourth, shut-down plant is coming from water boiling from the spent fuel cooling tank, which is outside the containment vessel (of course). The pool sustained damage during the quake, and apparently has been leaking, so there's not enough water to keep the tank below the boiling point.

Now, of course, there's the possibility of the spent fuel rods being exposed directly if the water boils off sufficiently, which will raise the levels of emissions even more.

"The pools are indeed inside the outer containment structures (the ones that were seen to blow apart). My understanding also is that the fire was (is?) in one of those, but that the fourth reactor is in cold shutdown (although it still would need coolant circulating, and the "cold" part seems odd unless perhaps it's a very new core). Most of the pools are now out of sight, covered by debris from the collapsed containment ceilings, and I've seen nothing as to their status. Clearly they could be big trouble."

Steve - looks like the pools might as well be outside for all the good these relatively lightweight buildings are doing. They're obviously not airtight as steam from the boiling water in the storage pool is getting a free pass outdoors. Of course this fourth building might've been damaged by the quake or the recent fire but I don't think this scenario of losing storage pool water to the point where it boils off was thought to be at all likely in their design/planning.

I know the storage tanks at Trojan were built in the ground, like swimming pools, rather than above ground, though they could leak into the ground I'd think this would be a slower process than an above ground tank draining after earthquake damage ...

"Dhogaza, I hope you're right about the vessels, but one thing I can tell you is that they weren't thinking about this scenario when those things were engineered. Also, it might take a couple days for the fuel to melt through, so I'll be holding my breath until such time as the physical status of the cores can be confirmed or there's a distinct cooling trend that precludes the possibility of a melted core."

I think, as of this morning, I'm officially abandoning optimism ...

Holly Stick said...

About public perception, balancing risks etc.:

http://www.theoildrum.com/node/7661

J Bowers said...

I believe the Japanese will be dropping water on the pool from helicopters to keep it full. The biggest problem (according to a nuclear expert with indirect contacts in the plant, just interviewed on the BBC) is dealing with the hydrogen build ups.

Dallas said...

Dhogaza,

The pond thing is interesting. The spacing of the spent rods should prevent reaction between rods. If the quake/tsunami damaged the racks holding the rods, there could be an increase in reaction if they became more closely packed. That I don't know. That is as much speculatin' I would do.

There is a need for short term cooling of spent rods that depends on the chemical make up of the used rods. There are a lot of relatively short lived transient isotopes. That is why water and/or boron is used, to moderate the reaction potential. Temperature wise, the spent rods are warmer/hot enough to warrant cooling, but far from being so hot there is danger of melting or starting a fire under normal handling. This case I would classify as abnormal.

Steve Bloom said...

Dallas, you need to read and write more carefully. For example, you claimed that Navy reactors are modular, which they most assuredly are not, I corrected you, then you went off on a tangent based on what appears to be an assumption that I had claimed there was no such thing as a modular reactor. Similarly, you seem to want to make some point about the degree of enrichment when it's irrelevant to the current situation and I only raised it to point out how it is Navy reactors can be so small (although not modular). Again, you don't know much about this stuff, so maybe try asking questions.

The problem with the pools isn't initially fissioning, but melt from the residual heat. The potential for this will vary a lot depending on the composition, age, quantity and spacing of the rods. An associated risk is heat setting the zirconium cladding on fire, which is what happened. Note that it's the only thing in those pools that can burn. It's good that they seem to have gotten it out, but there's still a risk of much worse if the fuel damage was extensive. The (probably still very unlikely) worst-case scenario for the fuel in the pool is indeed the China Syndrome, although as with a core meltdown fissioning could only occur if the fuel concentrates enough. On the face of it that's less likely with used rods, but as I understand it new rods are also kept in those pools. In principle there's way more than enough fuel for a self-sustaining reaction.

To repeat, a worst-case for the pool fuel is highly unlikely, *but* if they're forced to evacuate due to a core meltdown the only remaining method to deal with the cores or the pools will be to drop boron and water from helicopters. IIRC that was ineffective at Chernobyl, to say nothing of quickly fatal for the pilots involved.

Steve Bloom said...

*sigh* Dallas, in a pool there should be zero chance of fissioning beyond the low background rate. The water is there *solely* to carry away residual heat, not out of a direct concern about fissioning, as by itself the water enhances fissioning. Possibly they add boron (a neutron "poison") to it as a precaution, or perhaps to pack the rods closer. The pools aren't cheap, so there's an unfortunate tendency to want to stuff too many rods in.

"Abnormal" is certainly correct, though.

Steve Bloom said...

Is it time for someone, perhaps Eli, to revisit the points made at the opening of this post?

It's unfortunate that Barry (a sincere and smart guy, but a biologist) swallowed the industry kool-aid on this. Perhaps he's not old enough to recall the similar arc of propaganda during the early course of the TMI and Chernobyl events (a little less so in the latter case since Western experts were more willing to say nasty stuff about Soviet nukes). IMHO he would have been better off emphasizing the clear distinction between the Gen IV concepts, which do have a strong inherent safety srgument, albeit rather tainted since the same argument got made for Gens I and II, and the present disaster-prone plants. As it is he's practically unrecognizable due to the emu eggs splattered all over his face. Oh well.

Steve Bloom said...

Hmm, a comment I submitted correcting Dallas on various of the misunderstandings in his 6:36 AM comment seems to have disappeared after it appeared to have posted successfully. Eli?

Dallas said...

The cooling pond situation poses a whole new set of unexplored situations.

http://www.facebook.com/note.php?note_id=202009433162184&comments

The IAEA Facebook page is being updated regularly.

Dallas said...

Steve, I just read some updates on the pond and it is a potentially "very" serious situation that should not have existed. What I said earlier is true under "normal" circumstances, but the pond now is definitely not normal. It is hard to tell for sure, but the spent rods in question are only about three months from cold shutdown (30 November scheduled shutdown) and may have been rearranged by the quake or over loaded per one Russian expert (can't find the link, but he was the Chernobyl lead clean-up guy). Definitely not a good situation if true.

Steve Bloom said...

Dallas, I'll wait to see if that comment reappears from limbo at some point, so for now I'll just repeat the datum that zirconium burns and was (is? -- it's so hard to keep track) the fuel for that fire. Let's see, burns, catalyzes hydrogen from superheated steam -- versatile stuff!

Yes, if they just came out of the reactor a few months ago they're still pretty hot in both senses (why the cold in "cold shutdown" is relative). My guess is that internal heat would be enough to melt them given sufficient time, although to all appearances the cladding catches fire first. Bear in mind that the cladding provides most of the structural strength for the rods, so if it burns away it's pretty much sploosh right to the bottom of the pool, and if that happens to enough rods...

Dallas said...

Steve, BTW, Hydrogen is commonly produced in the cooling ponds until the rate of decay decreases sufficiently. Given the situation, the hydrogen explosions were more likely due to hydrogen from the ponds and not the reactors. The significantly higher that expected radiation measurements indicate a source outside of the concrete main containment building. That will required people risking their lives to fix a mistake that should not have existed.

On the cooling requirements of spent fuel, the heat of the spent rods is 7% of the core temperature at shutdown, dropping to 1.5% one hour later then continues cooling over time at a decreasing rate.

http://en.wikipedia.org/wiki/Spent_nuclear_fuel

That can vary with fuel composition, so I would be happy to look at another source.

J Bowers said...

A new fire's apparently broken out at reactor four in the outer housing of the reactor's containment vessel.

Steve Bloom said...

Now I read in the NYT's latest that machine oil (any large industrial facility will have a store of a fair amount of that, at the least a few barrels worth) stored nearby *may* (and the source was in the U.S., not Japan) have been involved in the pool fire, although it's a mystery why that would ever have been described as a fire in the pool (as opposed to just involving it or next to it). If so, maybe the zirc didn't burn, or at least wasn't ignited by internal rod heating. But the same article notes that all three pools (not sure about the fourth) are boiling.

Steve Bloom said...

The old fire is dead, long live the new fire. :(

badger badger badger said...

Steve Bloom:

...if that happens to enough rods, they'll get a reactor back!

jcrabb said...

The world wide media silence on the number three reactor containing the far more dangerous MOX/Plutonium fuel reallly shows how we aren't up to using this stuff. It also exposes how much we are the nook industry bitches...wouldn't want to offend them by saying just how really fucked up their product is.

Jonathan Gilligan said...

NY Times reports that AEC warned in 1972 that this containment design was dangerous with respect to hydrogen explosions in an LOCA because it didn't give much volume for dilution.

Money quote from AEC memo: "What are the safety advantages of pressure suppression, apart from the cost saving?"

Dallas said...

jcrabb,

MOX/plutonium is a fast reactor fuel. They would have to had done some radical modifications to a BWR to use that. There are three of the 55 reactors that are advance design reactors, but Japan is a no plutonium ever nation. What was your source?

Steve Bloom said...

Dallas, re that last on the MOX, really, truly check your facts before posting. TIA.

Dallas said...

I stand corrected. They bought MOX from the French.

Steve Bloom said...

Ditto on the one before that, Dallas. WP articles have their limitations. You misconstrued a number of things. The hydrogen bit refers to waste cans. Even in those boiling pools, there won't be much hydrogen production since the steam isn't very hot. Regardless the hydrogen is known to have originated in the vessels and to have been released by venting. Knowing the decay curves for these rods won't tell you much given all the other factors involved. The crucial observation is that the pools are boiling, which makes it a dead-bang certainty that if they're uncovered for long enough they'll melt. One other thing to bear in mind is that even rods that aren't producing much heat but aren't being cooled will still get very hot due to accumulation of the heat. Calculating exactly how heating and melting will proceed requires knowing all the variables, which is impossible in the present case since there's been physical damage to the pools.

Steve Bloom said...

jcrabb, link for that fuel info? In any case it's a relief that the MOX is only in one unit.

Steve Bloom said...

Thanks for that info, Jonathan. Of course the point is that these things are so very expensive that there will be extreme resistance to replacing flawed (or simply less safe) designs before they have to be decommissioned due to aging.

adelady said...

I noticed that the French, who've got more nuclear experience than most, now rate this incident as more serious than TMI. Presumably the rest of the international nuclear community will follow suit in due course.

Steve Bloom said...

I wasn't aware there was any remaining disagreement on the point, Adelady. One would hope not.

A passage from one of the new NYT stories:

"That explosion on Tuesday was caused by hydrogen gas bubbling up from chemical reactions set off by the fuel rods in the pool, Japanese officials said. Inspectors from the United States Nuclear Regulatory Commission said they had been told that what was burning was lubricating oil from machinery near the pool."

OK, this pool (#4) is the one that boiled dry, which process would have created the superheated steam needed for hydrogen production, so that would make sense. Possibly the explosion then lit off the oil, with no zirc fire involved, which is relatively good news if so. Also on the plus side is that a hydrogen explosion can't recur there since the pool is now partially exposed to the sky. The other hydrogen for the other big explosions was sourced in the reactors. With the containment roofs gone, more such big explosions can't happen outside the reactors (nor inside so long as venting continues)but according to the same article small ones are ongoing. It sounds like hell for the remaining workers.

jcrabb said...

Link for MOX upgrade of No.3

http://search.japantimes.co.jp/cgi-bin/nn20100823a7.html

Dallas said...

The hydrogen production is by splitting due to radiation. It doesn't has to be supercritical steam. That was probably the bubbling or boiling noted since the pool temp was reported as 84 C around that time.

Pure Zirc, finely ground will burn, even spontaneousnessly combust. The melting point of the zirc alloy is around 1820 C. I don't think they were using actinide fuel.

Johnathan's paper explains a lot.

Steve Bloom said...

"pool temp was reported as 84 C around that time." Source? Getting a significant quantity of hydrogen via radiolysis under such circumstances seems unlikely. Source?

Re zirc fires, see this paper. The first paragraph:

"Because of the unavailability of off-site storage for spent power-reactor fuel, the NRC has allowed high-density storage of spent fuel in pools originally designed to hold much smaller inventories. As a result, virtually all U.S. spent-fuel pools have been re-racked to hold spent-fuel assemblies at densities that approach those in reactor cores. In order to prevent the spent fuel from going critical, the fuel assemblies are partitioned off from each other in metal boxes whose walls contain neutron-absorbing boron. It has been known for more than two decades that, in case of a loss of water in the pool, convective air cooling would be relatively ineffective in such a “dense-packed” pool. Spent fuel recently discharged from a reactor could heat up relatively rapidly to temperatures at which the zircaloy fuel cladding could catch fire and the fuel’s volatile fission products, including 30-year half-life 137Cs, would be released. The fire could well spread to older spent fuel. The long-term land-contamination consequences of such an event could be significantly worse than those from Chernobyl." (emphasis added)

Of course the NRC didn't much care for this paper, and until now there's been no opportunity for an experiment to prove or disprove it.

dhogaza said...

'Japan suspended operations to keep its stricken nuclear plant from melting down Wednesday after surging radiation made it too dangerous to stay.
Chief Cabinet Secretary Yukio Edano said the workers dousing the reactors in a frantic effort to cool them needed to withdraw.
"The workers cannot carry out even minimal work at the plant now," Edano said. "Because of the radiation risk we are on standby," he said.'

No more workers on site, the 6-reactor complex is free to explore the future on its own.

Well, at least I was smart enough to state in public that I was abandoning optimism many hours ago :(

Sigh.

Dallas: thanks for at least appearing to recognize that you've been very wrong on many points (me, too, in my optimism).

But I must say, Dallas:

"Steve, I just read some updates on the pond and it is a potentially "very" serious situation that should not have existed. What I said earlier is true under "normal" circumstances, but the pond now is definitely not normal"

Uh, it wasn't normal when you earlier posted, that was the friggin' point being made.

The elevated, above-ground swimming pool had been subjected to a 9.0 earthquake, and when the reports first came out, they made clear the fact that it had been damaged.

Steve Bloom said...

Thanks, j! OK, only the #3 core has MOX, but it's pretty new (good). Of the pools, possibly #3 would contain some new ones, but likely it's still the old set.

Steve Bloom said...

Workers withdrawn? Shit, Jesus, as I believe the phrase goes (apologies to delicate bunny sensibilities).

Radiation must have punched up, which can only mean bad things happening and probably right away. I really wonder if they got neutron counters in there at at an early stage (I would have). Those would have told them when the balloon was really going up, probably with enough warning to get people out.

Well, hopefully they can still spray water from a distance. Otherwise it really does look hopeless. They may try blowing off the remaining roofs and mass-dumpin boron, ala Chernobyl. That worked, eventually, sort of.

Dallas: What dhogaza said. Enthusiasm good. Lack of scholarship bad.

Steve Bloom said...

Rather than accept multiple Chernobyl-type events, would it better to bring in precision bombers or artillery (noting that these are available just off the coast) and blow apart any part of the facility that seems to be running away? Not sure. Local contamination might get worse, but things at a distance should improve. The Russians must have thought about that and not taken the option, but lots of things were different at Chernobyl, for starters that they probably didn't understand just how bad it could get. Well, U.S. warplanes being used to snuff runaway nukes would have to qualify as the biggest historical irony ever, IMHO.

dhogaza said...

Steve Bloom:

"Workers withdrawn? Shit, Jesus, as I believe the phrase goes (apologies to delicate bunny sensibilities)."

Yes, or Allah or the Great Void or whatever ...

"Radiation must have punched up, which can only mean bad things happening and probably right away. I really wonder if they got neutron counters in there at at an early stage (I would have). Those would have told them when the balloon was really going up, probably with enough warning to get people out."

It's becoming increasingly obvious that a six reactor configuration (obviously, as in most things engineering and management, existing to make things more efficient) has totally overwhelmed the response capability.

Which I will speculate - my speculation being upfront - was planned for a single reactor having an accident due to an isolated failure within the specific reactor and associated pumps, pipes, turbines etc.

In other words, it's starting to feel like they didn't plan for problems based on a possible multiple, rather than solitary, failure...

Well, not suprising, the seawall wasn't planned for a many-century scale earthquake, which (as I think I said somewhere up above) wasn't considered plausible back when the infrastructure was engineered.

Anyway, I'm going to bed soon, and I'll wake up in the morning to - most likely - increasingly negative reports from Japan.

Sigh ...

Most of my life I've been more or less in favor of nuclear power but ... without any trust in the corporations doing design and deployment ...

Dallas said...

Dhygaza,

The pool thing and the hydrogen explosions didn't make any sense until I saw Johnathan's link. I was wrong, but the pressure suppression system was wronger. Well, that should be a word. It looks like the three out of service reactors are suffering from the same problem only slower. Unit 5 is losing water in pressure vessel per the IAEA facebook page. Even a "safe" reactor is not safe with that design.

adelady said...

Workers have now been allowed back into the plant. So the radiation reading was "just" a spike. If this comes out better than it currently looks, it will be entirely down to these fantastic people.

dhogaza said...

Steve:

"Rather than accept multiple Chernobyl-type events, would it better to bring in precision bombers or artillery (noting that these are available just off the coast) and blow apart any part of the facility that seems to be running away? Not sure"

The containment vessels are still containing (with multiple steam/hydrogen venting events, but now that the relevant buildings have been blown up, hydrogen venting should be OK, the buildings don't exist so accumulations can't occur now so future explosions won't be tamped [increasing damage around the containment vessels etc) if they even happen, right?)

Blowing things apart ... bombs have this really bad track record of not doing what you want, even if they can be precisely aimed. I see what you're thinking - blow the fissile material before it can again attain a chain reaction - but, that's like doing a Chernobyl hoping to avoid ... ugh, not wanting to think about it.

No?

dhogaza said...

Dallas:

" I was wrong"

So was I, even though being better informed (if you'll allow me that), I was far too optimistic ...

Sigh.

dhogaza said...

"Workers have now been allowed back into the plant. So the radiation reading was "just" a spike. If this comes out better than it currently looks, it will be entirely down to these fantastic people.
"

adelady - where are you seeing that? AP as of 30 minutes ago doesn't have it, and says workers have been withdrawn (not watching TV news).

Whatever ... send them away, bring them back, send them away ... they have no clue as to what's going on.

I saw an announcement that we (the US) are sending people over to, among other things, evaluate the Japanese response.

My read is not what you might think (put down the Japanese) but due to the fact that 23 GE Mark I Boiling Water Reactors are in service in the US, and they've been previously criticized by the NEC, and they're worried ...

Steve Bloom said...

If workers aren't present to maintain water flow and control the venting, meltdowns seem inevitable. Those would in turn mnean massive amounts of fission products being blown into the atmosphere until the fuel burns itself out. Worst case is that the fuel burns into the ground and finds the water table, which I expect would allow the process to get a lot worse. Right now, the fuel configuration is known and so it ought to be possible to stop further fissioning. As I said, it would be a larger mess locally, but I suspect the Japanese would consider any alternative to a major plume drifting over the essentially unevacuatable Kanto plain to be worth considering.

Steve Bloom said...

According to the NYT, there was a mistranslation of the staement and in fact some workers had remained. But even a temporary radiation spike that caused them to pull out a significant number of the remaining 50 is quite bad news.

Dallas said...

Dhogaza,

It's a dark comedy! The drawings for the GE Mark I, pressure suppression system doesn't show the routing of the vent. Where ever it the hell it actually vents to is causing the pulsing radiation.

Dallas said...

Here from the NEI fact sheet on the pools and site linked below. The pressure suppression pool is not the same as the storage pool, that finally makes sense. The only boiling that should happen in the storage pool should be hydrogen. And the rods, if exposed to air may have some oxidation of the zircalloy case. I used more wiggle words because this situation really is making no sense.

http://resources.nei.org/documents/japan/Used_Fuel_Pools_Key_Facts.pdf
http://nei.cachefly.net/newsandevents/information-on-the-japanese-earthquake-and-reactors-in-that-region/

The pulsing radiation at one reactor might be due to damage to the pressure suppression chamber. The others?

Steve Bloom said...

You didn't wiggle nearly far enough, Dallas.

adelady said...

Some not so jolly reading for anyone with concerns or issues about the design and maintenance of these reactors. This bloke =seems= to know what he's talking about. The stuff about the emergency backup generators certainly sounds familiar.

http://www.gregpalast.com/no-bs-info-on-japan-nuclearobama-invites-tokyo-electric-to-build-us-nukes-with-taxpayer-funds/

Neven said...

It's unfortunate that Barry (a sincere and smart guy, but a biologist) swallowed the industry kool-aid on this. Perhaps he's not old enough to recall the similar arc of propaganda during the early course of the TMI and Chernobyl events (a little less so in the latter case since Western experts were more willing to say nasty stuff about Soviet nukes). IMHO he would have been better off emphasizing the clear distinction between the Gen IV concepts, which do have a strong inherent safety srgument, albeit rather tainted since the same argument got made for Gens I and II, and the present disaster-prone plants. As it is he's practically unrecognizable due to the emu eggs splattered all over his face. Oh well.

Steve Bloom, I fully agree with this spot-on observation. I hope Barry comes out of this unscathed.

Thanks to others for the link to the Greg Palast article.

jcrabb said...

adelady, thanks for great Greg Palast link. He definitively proves corners get cut, another nail in the coffin, basically proving the safety standards are impossible to guarantee, a fantasy. He shows that no matter how insanely, magically, technically safe a Power Station may be on paper, Human nature means there can be no guarantee Powerstations can be built 100% to the plan and with something as dangerous as Plutonium there can be nothing less than 100% guarantee of adherence to the plan.

On top of the current meltdown, one would think this should be enough to can the Nuclear industry, though I won't hold my breath, sadly I think it is going to take a smoking tunnel down to the Core to do that.

davey said...

Relevant to the last few posts here, the bunnies might find "An expert in one field is not the same as An Expert" by BoingBoing's science writer Maggie Koerth-Baker to be of interest.

jcrabb said...

This is interesting,

A plume of radioactive particles extending into the stratosphere from the Fukushima Daiichi reactor complex makes a mockery of claims that Japan’s nuclear crisis isn’t comparable to the Chernobyl disaster in 1986.

The stream of nuclear contaminants are being driven by an intense heat source consistent with exposed fuel rods burning in air, the process that inevitably leads to meltdown unless massive and prompt intervention is successful.

These radioactive clouds are now mixing with higher altitude air currents and being dispersed more widely across northern Asia and the north Pacific.

They are being tracked by the international Volcanic Ash Advisory Centre in London, which is authorised by the International Atomic Energy Agency to alert airlines and airports to accidental releases of nuclear contamination.

http://www.crikey.com.au/2011/03/16/japans-nuclear-farce-has-chernobyl-written-all-over-it/

Crikey indeed.

J Bowers said...

@ davey. Thanks for the link, where I see...

"On Monday, the essay was turned over to the Department of Nuclear Science and Engineering, which set a team of field-specific experts to editing it. The essay has now been re-posted at a new website, and it's been changed. The stuff many people liked about it—a clear step-by-step explanation of what happened during the early hours of the Fukushima nuclear crisis—is still there. But it's now been vetted for accuracy by people who are far more likely to know what is accurate and what isn't."

Eli and John, there's a new version of Josef Oehmen's essay. Perhaps you'd like to update the link?

http://mitnse.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

J Bowers said...

In fact, MIT NSE Nuclear Information Hub is a great blog. Highly recommended (if it hasn't been linked to already :/ )

http://mitnse.com/

jcrabb said...

http://my.firedoglake.com/kirkmurphy/2011/03/15/why-fukushimas-spent-fuel-rods-will-continue-to-catch-fire/

Interesting piece about how some of the likely 600000 spent fuel rods are catching on fire.

Anonymous said...

AN1

http://www.salon.com/news/japan_earthquake/index.html?story=/politics/war_room/2011/03/15/josef_oehmen_nuclear_not_worried_viral

J Bowers said...

So...

Sea levels rising, global temperature rising, CO2 levels rising, Southern hemisphere recently saw massive flooding, Russia was on fire last year, Arctic sea ice in death spiral, Greenland ice sheet melt accelerating, mankind's future is looking bleaker every year = Election of US Congress who decide AGW isn't happening partly based on a flawed poll that was overrun by morons from WTFUWT, and same Congress tries to defund the IPCC.

Radiation levels at the boundary of Fukushima nuclear plant at 1530 microsieverts/hour = Panic buying of iodine pills on US West coast.

Go figure. I don't suppose there's any evidence for a causal link between climate change and radiation poisoning?

Anonymous said...

There is nothing you can do about the reactor and it's no good pumping up one's personal anxiety when one can't pitch in and help. Go read James and lighten up.

Pete Dunkelberg

Holly Stick said...

More criticism of lax oversight by government and corporate inadequacies:

http://www.csmonitor.com/World/Asia-Pacific/2011/0316/Reports-Lax-oversight-greed-preceded-Japan-nuclear-crisis

jcrabb said...

Wow, the levels of bs piling up about this situation are piling up breathtakingly fast, it's like the Climate change "debate" in fast forward, the more extreme the evidence becomes the more extreme the bs become. This takes the cake so far,

"But officials at the International Atomic Energy Agency say the presence of MOX fuel does not add significantly to the dangers.

http://abcnews.go.com/Politics/us-send-special-nuclear-team-japan-nuclear-regulatory/story?id=13148044

Dallas said...

Steve, on the hydrogen production at the pool. Borates in the water increase the hydrogen production in the pools, Wikipedia - radiolysis.

On the zircaloy oxidation, thanks for the link. Other than in the reactor or within a few days of fresh fuel transfer to the pool, it is considered very unlikely. Do have a link with harder numbers?

BTW, A NRC spokesman said the pool at unit four is dry. In the paper you referenced, passive air cooling in event of water loss is part of the design of the racks/pool. If the racks are at max capacity (or rearranged), of course, that greatly limits the this worst case back up. I haven't seen anything on the loading of the pool or when the fresh rods were added. Any Idea?

Anonymous said...

Anonymous radioactive monster mouse,

So MIT has modified their post, but they still don't know what the fuck they are talking about.

"This process decreased the temperature of the fuel rods to a non-damaging level. Because the reactor had been shut down a long time ago, the decay heat had decreased to a significantly lower level, so the pressure in the plant stabilized, and venting was no longer required."

This is out and out speculation about events at the Fukushima plant and there is no credible evidence that it could be true.

The zirc water reaction is exothermic and like other metals that burn in the presence of water, once started this kind of fire will burn until the fuel, which in this case is zirconium, is exhausted.

It's like during the Vietman war, on aircraft carriers, occasionally, or too frequently, for the sailors on the Forrestal, nicknamed the Forrest Fire, when jets caught on fire, they put the fires out by dumping the aircraft into the sea.

Jesus, MIT nuclear engineering department, get a clue.

seamus said...

Just now, officials in Japan said there was still water in unit #4 Spent Fuel Pool, which is why they dropped water by helicopter on the SFP at unit #3 (instead of #4) today. The site was surveyed yesterday (Wednesday) by helicopter and they confirmed water in the pool at #4.

Water cannon trucks are going to try next.

Very grave.

David B. Benson said...

Jeff Masters explains the meteorology; no hazards to anybody at this time.

seamus said...

Jcrabb, check your sources. The radiation levels/spread of radioactivity have not been anywhere near the extent of the Chernobyl accident.

dhogaza said...

Dallas:

"Here from the NEI fact sheet on the pools and site linked below. The pressure suppression pool is not the same as the storage pool, that finally makes sense."

No one was claiming they were the same (and it's incomprehensible that they would be the same), so I guess this is a repeat of your previous "I'm ignorant" stuff?

dhogaza said...

"BTW, A NRC spokesman said the pool at unit four is dry. In the paper you referenced, passive air cooling in event of water loss is part of the design of the racks/pool"

Yes, this is exactly why French and US nuke experts are saying "oh, loss of coolant in the pools is no problem". (NOT.)

And why the Japanese are saying, "who cares if the pools have water!!{", rather than "the spent fuel pools still have water!!!!"

Hmmm .... oh wait.

dhogaza said...

But, no, it's not Chernobyl, which is why it's been elevated to a level 6 from level 4 (a few days ago), making it worse than TMI (level 5) but less than Chernobyl (level 7, top of the scale, which might simply denote an paucity of imagination).

adelady said...

Not Chernobyl. As I understand it, these reactors can never "go Chernobyl" as in a single massive explosion. (But in this world I suppose even the most unlikely things can happen.)

What they =can= do is start a continuous, near unstoppable reaction. Unstoppable because no-one could get close enough to do whatever as yet unknown actions would be required to stop it. So instead of a single huge release a la Chernobyl, the result would be a long-term release - which would be lifted into upper air because of the heat of the reaction.

It's a very, very good idea to do whatever, no matter how extreme or even foolhardy, can be done now to avoid this outcome.

jcrabb said...

seamus,
I think my link was trying to point out the Fukushima situation is similar to Chernobyl in that there is enough heat to lift radioactive particles into the Stratosphere, as stated by the London Volcanic Ash Advisory Centre (VAAC).

As to the volume of particles, give it time, considering that there are six reactors at Fukushima, seems reasonable to say that it will be worse than Chernobyl, as it only takes one reactor's fuel rods to start burning to make all the other Reactors inaccessable thus uncontrollable.

Efforts to restore Electricity will be pointless if the cooling systems have been damaged in the explosions of any of the reactors, I am beginning to wonder why they built 6 next to each other, nothing like upping the odds...lucky it's not a dice.

Steve Bloom said...

Adelady, what gave Chernobyl the potential for getting as bad as it did was the fact that the graphite moderator was ignited. Arguably it would take several of those BWRs melting down to get similar amounts of material transported off-site. That chock-full pool has the potential to take things a lot farther.

This current thread at DKos has lots of interesting material.

J Bowers said...

Handy PDF of radiation levels as of 20:00 March 16th

http://www.mext.go.jp/component/a_menu/other/detail/__icsFiles/afieldfile/2011/03/17/1303727_05_1.pdf

The BBC's live updates also seem less sensationalist than others

http://www.bbc.co.uk/news/world-middle-east-12307698

Interesting quote from the director of nuclear engineering at Imperial College, London, Prof. Robin Grimes:

"The sea water is dispersing quite a lot as it impacts onto those reactors. Actually in some ways, that's good because you wouldn't want the full force of all that water which is, of course, many, many tonnes of water hitting in one place."

The water cannons couldn't be used.

adelady said...

Steve, thanks for that, I think.

Maybe I'll go back to a diet of MSM only. If what I see is alarming, I can soothe myself with a pat on the shoulder and tell me they're usually wrong about important stuff.

Dallas said...

dhogaza,

"No one was claiming they were the same (and it's incomprehensible that they would be the same), so I guess this is a repeat of your previous "I'm ignorant" stuff?"

Yes, since I am not privy to all the information needed to be fully informed. The Hydrogen production possible in the spent fuel pools has been a big question. Several reports seem to have been confusing the suppression pool with the SFP. Steve wondered, as I did, how significant amounts of hydrogen could be produced in the spent fuel pools. What types and what concentration of boron compounds in the impact hydrogen production. Saltwater added to the SFP will also change the chemistry.

The report Steve linked states the chance of criticality in the SFP in not zero. The chance of a Zicraloy cladding fire in the pool is also not zero. Then, that is not very informative is it?

So I am ignorant of quite a few things.

As far as my walk away comment earlier. That is now being considered as a valid safety measure. Not only to reduce potential harm to emergency workers, but to reduce potential spread of radioactive material. The "Dry" well in the containment building is there by design for a reason.

Anonymous said...

Anonymous radioactive monster mouse says:

Eli,

Any chance you would post that the links above have mislead you and that the events at Fukushima are indeed serious.

Brave New Climate is an unreliable source in this case. As would anyone saying the hydrogen is coming from radiolysis of water.

seamus said...

I don't understand why you guys are going on about hydrogen generation in the SFP, and whether it's okay if the spent fuel rods are exposed to air. There's no roof on unit #3, so any hydrogen being generated shouldn't accumulate. The issue is the water in that pool is getting down to the point where we have to worry about the fuel rods being exposed. That's not a good thing at all!

It seems that the water cannons may have had some success. Thursday evening they sprayed 30 tons of water up into #3. We'll see in the morning (currently it's ~3:30am Friday Japan time).

While the critical work to get water into those pools continues, work goes on to restore high voltage power and hook up some water pumps.

Dallas said...

Seamus,

The rate of SFP hydrogen production would give you an idea if there was oxidation of the zircaloy if you knew what would be normal for the pool. If there were no boron in the SFP, there would be very little H2 production. Since the one reactor that was offline for service had fires, it is easy to assume that the h2 was produced by Zirc oxidation, which leads to wild speculation.

Steve Bloom said...

Shorter Dallas: wild speculation. Yes.

jcrabb said...

I don't understand why there is any question that some of the fuel rods are on fire, what else could be continually superheating particles to create the plume as recorded by the London Volcanic Ash Advisory Centre.

Anonymous said...

@jcrabb

How the heck have the guys in London "measured" the radioactive particles in the "plume".

IMHO they are "opining" that IF there are tons of radioactive particles in the "plume" this is where they would be.

Note that much of the radiation at the site is Gamma radiation....

Harvey

Anonymous said...

Do remember, that in the 50s and 60s Lots of above ground nuclear blasts sent all kind of radiation all around the world. I know for a certain that my teeth contain the evidence...

http://alethonews.wordpress.com/2010/12/22/seeking-new-clues-to-cancer-risks-from-atom-bomb-tests/

Sooooooo... How does the above release of radioactive material compare to 3mile island and the current Fukushima problems...

Harvey

J Bowers said...

Engineers have managed to lay a cable to Reactor 2.

http://www.bbc.co.uk/news/world-asia-pacific-12779512

badger badger badger said...

I have no idea whether the concentrations are high enough for it to be detected so far away, but I can readily imagine how that would work. You don't need much material to get a spectrum.

Back in my radiopharmaceutical days, the process for making thallium 201 for cardiac testing involved diluting it to the point that it was chemically undetectable, but still good for imaging a half-life or so later.

badger badger badger said...

PS Don't tell any homeopaths.

Dallas said...

Jcrabb,

The rods inside the reactors are damaged, meaning a partial melt down. One I believe is ~70% and another ~ 40%. Vented steam from the reactors will contain more radiation and exotic isotopes. They should be the source of most of the radiation.

The spent fuel pool status is not very clear. Since they are not in containment, they pose a much greater risk, IF they regain some level of criticality. With the pools full, there is very little radiation hazard near the pools, so they would release virtually no radiation. As stated by one of the Japanese spokesmen, the need for cooling is not a major issue at the pools. He also stated that water is not even needed. I happen to agree with his statement as far as spent rods melting, catching fire or going critical. There will be more radiation in the area of the pool, of course, but no mechanism to transport the radiation any great distance. I, of course, only stayed at a Holiday Inn Express and did not not get my PE stamp.

The reason I happen to not agree with the consensus, is that the average temperature of the spent fuel rods would be less than 45 C if the reactor core they were removed from operated at a 3000 C temperature. A touch high for a BWR, but what the heck it is just an estimate. With any reasonable spacing and loading, the pool water should not boil, it should slowly evaporate. The storage racks in the pool are designed to passively cool the spent fuel rods in the event of sudden water loss, a missile strike for example.

Maintaining water level in the pools is critical for shielding radiation for emergency and plant workers needed in the area.

There are theoretical situations that could occur in the pools, renewed criticality and cladding fire/oxidation. A cladding fire is technically a melt down because the fuel assembly is damaged. The melting point of the fuel pellets is much higher than the 1000 C needed for a cladding fire. There is also an even more unlikely chance that the loose fuel pellets could congregate in one area of the pool bottom in sufficient number to renew criticality. Renewed criticality is further complicated because the fuel is spent, making the geometry of the loose pellet that get together very important.

Remember that is just my take.

While I am typing, what is a small modular reactor? It is a small reactor that can be factory assembled and transported to the power generation site. Their basic design is remarkable similar to US Navy missile submarine power plants, like those commonly seen at King's Bay Naval Submarine Base.

jcrabb said...

@ anonymous, another body is talking about it,

From the WSJ,

http://online.wsj.com/article/SB10001424052748703818204576207011282898754.html

"The radiation-detecting network is run by the Comprehensive Test Ban Treaty Organization, a Vienna-based group that monitors any breaches of the test ban. It runs more than 60 such stations, including two in Japan. A unit in Kamchatka, Russia, more than 1,000 miles northeast of Fukushima, was the first to detect signs of the radiation.

Dr. De Geer said the terms of the treaty prevented him from divulging specific details, such as the exact readings of different radioactive isotopes picked up by the monitoring network."

and on the state of the fuel rods,

"Overheating fuel rods then discharge gaseous forms of certain volatile radioactive elements, including cesium, iodine, strontium and tellurium

Tokyo Electric Power Co., the Fukushima plant's owner and operator, has said cesium has been detected at the plant, but it was unclear what levels were found."

Interesting that the CTBTO can determine the levels of Cesium and TEPCO are 'unclear' about levels.

Seems there are two diferent realities going on here, the American evacuation of Japan or the Japanese 'Cesium..just a bit'

EliRabett said...

Probably more than TMI and less than Chernobyl. Also, most is headed out over the Pacific.

Jakerman said...

Two points:
Firstly, even low doses of radiation “pose some risk of adverse health effects” (where low does means zero to about 100 millisievert (mSv)).
http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11340

Secondly, children are affected more by low level radiation; and our accepted exposure limits (determined via study of mainly adult exposure) are not sufficient to determine the response to neither child nor in utero exposure.
“A detailed analysis of the many studies of childhood cancer risks from diagnostic in utero exposures concluded that a 10-mSv dose to the embryo and fetus does cause a significant and quantifiable increase in the risk of childhood cancer (3); Mole (16) has argued that the most reliable risk estimate from these studies comes from prenatal examinations in Britain during the period 1958–1961, for which the estimated mean fetal dose is 6 mSv and the odds ratio for childhood cancer deaths is 1.23 [95% confidence interval (CI) = 1.04–1.48]..

http://www.pnas.org/content/100/24/13761.full

Take away point: Get the children and pregnant women away from those areas of increased radiation exposure.

jcrabb said...

Dallas,

I don't see how this can be defined as partial melt down, as that sugggests the process has been stopped.

The storage pools are at the top of the Reactors, which no longer exist, the idea that there is a perfectly unharmed swimming pool in all that rubble doesn't seem likely.

This image of No.4 shows massive damage around it's storage pond.

http://www.latimes.com/health/la-sci-quake-radiation-workers-20110318,0,5659183.story

I wonder who the Einstein was that thought it would be good to store thousands of spent rods above a Nuclear reactor, may as well store them next to a Volcano.

The 'safety' pamphlet says they are stored there for ease of operation, more like saving a few bucks on water pumps'n'stuff.

Anonymous said...

Anonymous, if you are not satisfied with Brave New Climate you can always go to Daily Kos for the whole enchilada.

Pete Dunkelberg

Dallas said...

Jcrabb,

Melt down is not a very good term. The only reason it is considered a partial may be that the melting point of the fuel pellets is much greater than the cladding. So the meaning of the ~70 is not very clear in terms of actual fuel melt.

I am more concerned with the way the relief steam was handled than the location of the pool. Crisis pressure relief could easily be routed so that the steam/hydrogen is handled much more safely with this design. Condensing the steam would greatly reduce the spread of radiation and not blow so many buildings up.

jcrabb said...

Apparently fuel rods are too hot for Concrete over ala Chernobyl, I propose constructing walls off-site and piece them together around Reactor to make worlds largest, covered, heated swimming pool, now.

Jakerman said...

There are at least two significant problems with the Banana Equivalent Dose used in this thread. Firstly, for a given total increased radiation exposure level, the increased risks are higher for acute exposure than for prolonged exposure. That is, 20 bananas per day for 365 days is a lower cancer risk than 40 banana per day for 6 months. Which is lower risk than extracting all the radioactive potassium from 7,300 bananas and consuming it in one week.
http://www.ncbi.nlm.nih.gov/pubmed/9952308?dopt=Abstract

The second problem is that radiation levels are sieverts per hour (micro or milli). So if a banana is equivalent to 0.1 micro Sv, an exposure of 1 milli Sv/hr is equivalent to 10,000 bananas per hour.

Radiation levels now appear to be in the range of millions of bananas per hour.

http://weblogs.baltimoresun.com/business/hancock/blog/2011/03/japan_reactor_crews_the_pinnac.html

Jakerman said...

A useful analogy, my DNA is adapted to an optimal exposure of say 'x' UV radiation per day (or bananas/day). I can receive 'x' UV/day for 70 years in Europe with a certain y risk of skin cancer. But if I absorb 1.5x per day by moving to Australia, my risk of skin cancer increases. If I have a child in Australia their risk is even higher (http://www.springerlink.com/content/u655635866580g23/).

Finally, while I might be adapted to say x bananas per day of UV, if I receive a years worth of UV radiation in one day I will be incinerated.

dhogaza said...

"I don't understand why you guys are going on about hydrogen generation in the SFP, and whether it's okay if the spent fuel rods are exposed to air. There's no roof on unit #3, so any hydrogen being generated shouldn't accumulate"

Google "containment structure", which the building wasn't, even before it blew up.

dhogaza said...

"The reason I happen to not agree with the consensus, is that the average temperature of the spent fuel rods would be less than 45 C if the reactor core they were removed from operated at a 3000 C temperature. A touch high for a BWR, but what the heck it is just an estimate. With any reasonable spacing and loading, the pool water should not boil, it should slowly evaporate."

That would be a cool proclamation of reality if it weren't for the fact that temps in the 60C range (and rising) have been reported by the Japanese.

Sometimes reality impinges on Dallas's insistence on his personal reality, which after all has been repeatedly shown to be over "optimistic".

dhogaza said...

"The reason I happen to not agree with the consensus"

You are doing a good job of mimicking climate science, evolutionary biology, and other denialism, though I'd guess it's accidental.

Thanks, though.

dhogaza said...

"There are at least two significant problems with the Banana Equivalent Dose used in this thread. Firstly, for a given total increased radiation exposure level, the increased risks are higher for acute exposure than for prolonged exposure. That is, 20 bananas per day for 365 days is a lower cancer risk than 40 banana per day for 6 months"

Even better, 6000 microsieverts over a short term and you die ... over a short term.

You can ignore things like cancer probabilities over a lifetime dose at such a level over a short period of time, because you'll be dead. Those at Chernobyl so exposed all died within a month, despite medical care.

dhogaza said...

Eli:

"Probably more than TMI and less than Chernobyl. Also, most is headed out over the Pacific."

Probably more than TMI? No, certainly, even the Japanese were saying that a couple of days ago, and they're not exactly reversing their reputation for being hesitant to admit to fucking up.

Less than Chernobyl? Yes. And hopefully forever.

It's been rated a "6" on the accepted international 1-7 scale and Japan isn't arguing otherwise, with TMI a "5" and Chernobyl a "7" (presumably, anything worse would leave to a crash meeting of those who could declare the scale to be 1:8 or whatever ...)

Jakerman said...

When the shit his the fan, the bulk of the (distributed and hence resiliant network) fans keep working:

http://www.huffingtonpost.com/kelly-rigg/battleproof-wind-farms-su_b_837172.html

Jakerman said...

"You can ignore things like cancer probabilities over a lifetime dose at such a level over a short period of time, because you'll be dead."

Good point, and while tens or hundreds of plant workers will be exposed to high level radition, orders of magnitude more face the risk of moderate to low yet increased radition exposure.

J Bowers said...

The Beeb has a very good animated graphic illustrating what happened in the plants.

http://www.bbc.co.uk/news/world-asia-pacific-12726591

Dallas said...

dhogaza,

Yes, the 45 C is only an estimate of the new spent fuel rods. They are hotter than the rest because of the full fuel transfer and they all are generating decay energy. The decay energy of the new rods is some where between 0.5% and 0.21% of reactor gross capacity. Enough energy that the unit 4 pool is rated as an INES 3 incident.

Consensus may have been a poor choice. How about, I was one of the few that found the SFP statement reasonable. At least with the new INES ratings you may be able to get some of your optimism back.

Dallas said...

jcrabb said...
"Apparently fuel rods are too hot for Concrete over ala Chernobyl, I propose constructing walls off-site and piece them together around Reactor to make worlds largest, covered, heated swimming pool, now."

That would be cool! A Godzilla/Sea World kind of theme park.

seamus said...

Dhogaza, I know the SFPs are outside of the containment structure. As I understand it, the concern is not whether there is any hydrogen gas being generated. The focus is on getting the water level up in those pools so that the fuels rods don't become exposed, which could result in a significant release of radioactive particles. Also, getting more water in the pools will reduce the local radiation coming from them so that workers can do stuff around the reactor buildings, like getting the power and water pumps going again.

Google says that a CAT scan gives you 6000 to 10,000 microsieverts. How long does a CAT scan last, about an hour or so? The authorities in Japan are being very careful about the dosages that the workers are getting.

Not much point in trying to convince people that ~even if~ there's a major release of radioactivity in Japan, what might reach the U.S. is non-significant. Hysteria reigns, and the internet is a stupidity multiplier.

J Bowers said...

James Annan mentioned on his blog that there was to be a collection in Yokohama to help the relief effort, but people are afraid to go outside. I also just read a comment at the BBC Live (Japan earthquake) blog where someone says everyone's afraid to go outside. I'm wondering whether the nuclear disaster porn in the media could possibly be causing a reduced relief effort within Japan.

BBC:
"1954: Paul Morris is staying with his wife and daughter in Bobata, 40km (25 miles) from the Fukushima plant, and he tells the BBC they're extremely worried: "No-one goes outside any more, the roads are so quiet, you know and I only keep in touch with my family and friends, you know, so we don't know the extent of the exclusion zone. A lot of people's left okay but it's so scary, you don't know what to do you know, it's terrible.""
http://www.bbc.co.uk/news/world-middle-east-12307698

James Annan:
"(Actually, I don't think it is quite that bad - they are not really being forgotten. But just for example, a minor collection of aid from some people in Yokohama has been postponed because some people are apparently worried about going outside!)"
http://julesandjames.blogspot.com/2011/03/more-stupid-hype.html

Steve Bloom said...

Dallas: "While I am typing, what is a small modular reactor? It is a small reactor that can be factory assembled and transported to the power generation site. Their basic design is remarkable similar to US Navy missile submarine power plants, like those commonly seen at King's Bay Naval Submarine Base."

This really is quite tiresome: No, it isn't.

Dallas said...

Steve, If I am wrong I apologize. The Nuscale design combines modules of 45MW LWR's to configure plants up to 540 MW. Electric boat is supposed to be one of their partners. I thought it was a very interesting concept, because the module were sized to be shipped by barge, rail even trucks.

http://www.nuscalepower.com/ot-Scalable-Nuclear-Power-Technology.php

I just thought the design showed promise for the near term until Molten Salt reactors were ready.

Steve Bloom said...

Dallas, they're similar only in the sense that both are small LWRs. That's not "similar" in any useful sense. Among other differences, remember the fuel the naval reactors use.

Modular reactors may indeed show promise, although we'll have to see. Whether they do or not was never very relevant to this thread.

dhogaza said...

"The focus is on getting the water level up in those pools so that the fuels rods don't become exposed, which could result in a significant release of radioactive particles. "

Which has actually been happening for a couple if days, unless you accept the Japanese "we're cool" assessment vs. the US (invited) overflights showing highly radiative plumes above the reactors.

French and US experts have been saying for days that fuel rods have been exposed both in situ and in the spent fuel ponds.

dhogaza said...

"Modular reactors may indeed show promise, although we'll have to see. Whether they do or not was never very relevant to this thread."

It has absolutely nothing to do with the problems in Japan, but apparently are relevant to Dallas's desire to sweep it under the rug.

Yes, promise. We're all awaiting the nuke industry's ability to back theoretical science with sound engineering and operations and maintenance protocols that work for decades in the real world, even in the face of siting issues (earthquakes and tsunamis, for instance).

jcrabb said...

Humour section:

http://tv.gawker.com/#!5783191/ann-coulter-to-bill-oreilly-radiation-is-actually-good-for-you

Denialist methodology seems to be applicable across the board, with the extreme antiscience shock troops charging across the parapet, making the most insane pronouncements, capturing ground through 'shock and awe' of pure stupidity, planting the tattered flag of doubt, enabling the following 'regular' antiscience troops, who are no less incorrect, to sound reasonable and hold the captured ground, defending the abused flag, maintaining the status quo.

J Bowers said...

@ jcrabb, they're out of their boxes, alright, and revealing how their ideology trumps their humanity.

"CNBC anchor Larry Kudlow was also in hot water after stating he was grateful the human toll was far worse than the economic cost of the crisis."

http://www.dailymail.co.uk/news/article-1367698/Radiation-good-says-Ann-Coulter-weighs-Japans-nuclear-crisis.html

Own goals, methinks, once the logic seeps in that if the same happened in America they'd be more concerned about the money than the family.

jcrabb said...

@J Bowers,

Own goals all round, with the Repub's recent repeal of the laws of physics in the House and the rise of the t.baggers, their ideology also trumps reality.

America seems to be in a whole different ball game, which is a concern considering their participation in reduction is essential, unless they go broke and start shooting each other even more.

seamus said...

Dhogaza, there's a difference between "radiation", hazardous in the immediate area, and "plumes of radioactive particles" carried aloft. As far as we know, the former is what is being detected, not the latter. Of course there may be some particles emitted from everything that's happened, but as far as we know the spent fuel rods are not ablaze.

There's a difference between exposed fuel rods in the cores (likely, but contained) and in the spent fuel pools (possible, but not confirmed).

In the media, "nuclear expert" apparently includes plenty of folks with an agenda, such as Joseph Cirincione with the Ploughshares Fund.

It's an ugly mess and I'm not defending any Gen II reactors. We should skip Gen III and go straight to Gen IV designs.

These tsunamis were so devastating. The water swept over a 10m high tsunami wall in one town.

dhogaza said...

"Dhogaza, there's a difference between "radiation", hazardous in the immediate area, and "plumes of radioactive particles" carried aloft. As far as we know, the former is what is being detected, not the latter"

Which would be why, of course, small amounts of radiation from the plant has been detected in California, because it's in the immediate area ...

They've been mapping the plume for days, which thankfully has been been blowing out to sea for the most part.

"There's a difference between exposed fuel rods in the cores (likely, but contained) and in the spent fuel pools (possible, but not confirmed)."

Head of the NRC has said otherwise regarding the spent fuel pools. Remember, we've been flying sensors on helicopters and fixed-wing aircraft over the site (with Japanese permission), I don't think the head of the NRC simply pulled this statement out of his rear.

Holly Stick said...

Report of radiation in milk and spinach near the reactors, and traces of radioactive iodine in Tokyo tap water:

http://www.cbc.ca/news/world/story/2011/03/19/japan-radiation.html

Jakerman said...

@ Seamus:

"We should skip Gen III and go straight to Gen IV designs."

Gen IV such as those cooled with sodium metal? What would the result be if an earthquake cracked the coolant housing in such a reactor (say a on a seal or joint) ?

Can the passive cooling provided by sodium work if its combusted by contact with air?

seamus said...

"U.S. Nuclear Regulatory Commission Chairman Gregory Jaczko said in Washington that all the water was gone from the spent fuel pools at Unit 4 of the Fukushima Dai-ichi complex. Japanese officials denied it. If Jaczko is correct, it would mean there's nothing to stop the fuel rods from getting hotter and ultimately melting down. The outer shell of the rods could also ignite with enough force to propel the radioactive fuel inside over a wide area. Gregory Jaczko did not say Wednesday how the information was obtained..."

Yep, nothing confirmed. Speculation.

Jakerman, did the bigger-than-design-basis earthquake damage any coolant pipes on any reactors in Japan? While I'm not a huge fan of nuclear (fission) energy, I don't think we have a choice. So I'm a big fan of the liquid sodium fast reactor, yes. I'm also a big fan of wind and solar, but will they be enough? Remember, energy demand is going up, especially when you consider things like the billion plus people in India without electricity.

seamus said...

quote is from "No water in spent fuel pool of Japan nuclear plant, says NRC"
http://www.news10.net/news/local/story.aspx?storyid=128670

Jakerman said...

Seamus: "did the bigger-than-design-basis earthquake damage any coolant pipes on any reactors in Japan?"

I don't know, do you?

As I asked,

"What would the result be if an earthquake cracked the coolant housing in such a [sodium mediated] reactor (say a on a seal or joint) ?

Can the passive cooling provided by sodium work if its combusted by contact with air?"

Jakerman said...

BTW, we should not limit our concern to coolant pipes.
when dealing with reactive metals such as sodium, itts the whole containment system for sodium that we should be concerned with (seals, joints etc.

And remember they need to maintain an hermetic seal.

seamus said...

Radiation from Fukushima plant detected in Sacramento, EPA says

One station in Sacramento detected "minuscule quantities" of a radioactive isotope, xenon-133, that scientists said they believed came from the reactors at the stricken Fukushima plant.

Believed? Or confirmed? Hmmm. Seems possible those xenon-133 particles could have come from plants in California.

But the level detected would result in a "dose rate approximately one-millionth of the dose rate that a person normally receives from rocks, bricks, the sun and other natural sources," according to an EPA statement.

seamus said...

Yes, liquid sodium can combust when exposed to air, and reacts violently with water, those are certainly drawbacks of using it. It also has many advantages over other coolants.

The question isn't "should we build nuclear?" The question is "which designs are better?"

Jakerman said...

Seamus: "The question isn't "should we build nuclear?" The question is "which designs are better?"

A useful question is, 'are there any nuclear designs that can be made safe within earthquake zones?'

EliRabett said...

Sodium reacts with the water vapor in the air, not the air. FWIW but a lot of people miss this

J Bowers said...

Not all Gen IV reactors would use sodium.

Thermal reactors:
Very-high-temperature reactor (VHTR)
Very-high-temperature reactor (VHTR)
Supercritical-water-cooled reactor (SCWR)
Molten-salt reactor (MSR)

Fast reactors:
Gas-cooled fast reactor (GFR)
Sodium-cooled fast reactor (SFR)
Lead-cooled fast reactor (LFR)
Energy amplifier

For those left with the impression that calamity is assured because all Gen IV reactors would use sodium.

http://en.wikipedia.org/wiki/Generation_IV_reactor

Dallas said...

Okay, I am definitely out of my depth on the Zircaloy fire potential.

This study from 1979 has the most information based on computer modeling. "Severe Accidents in Spent Fuel Pools
in Support of Generic Safety
Issue 82"

"Thus clad "fire" propagation appears to be a real threat but the basic question remains as to what are the "critical" conditions for initiation of oxidation and what the uncertainty is for a given spent fuel configuration."

One of the interesting factors was the size of the ventilation hole in each rack cell. A 3" hole greatly reduced potential for initial oxidation and spread while a 1.5" hole increased the potential.

That study was for a dry pool. The situation at unit 4 is more likely a partially filled pool, which is a different critter. I read a number of reports on lab tests to simulate rapid oxidation of Zircaloy under various conditions. They were able to oxidize hollow tubes to different degrees in a realistic environment. Autoclave tests were of limited value because conditions were significantly different to what would be expected in the real world. The material used to build the racks is an important factor as well. So I don't know.

dhogaza said...

seamus:

"One station in Sacramento detected "minuscule quantities" of a radioactive isotope, xenon-133, that scientists said they believed came from the reactors at the stricken Fukushima plant.

Believed? Or confirmed? Hmmm. Seems possible those xenon-133 particles could have come from plants in California."

So a normally operating plant in California is venting an unreported radioactive plume, while there has been no radioactive plume from any of the four damaged Japanese plants.

That's your hypothesis?

Yes, levels are low, but the Japanese have been *openly* venting the damaged reactors, so any claim that there's been "no radioactive plume from the damaged plants" presumes they're lying about it.

Don't be silly.

I also believe we need fission power in our future. I believe the accident in Japan will be of little consequence health-wise except for those actively fighting it onsite, though it will be a huge economic hit as it's going to take a couple of decades before they're done dealing with the plants (as was true with TMI).

But claiming there's no radioctive plume from the site when the Japanese openly admit to venting radioactive steam from a couple of the plants is downright silly.

John said...

Here's a useful source of information about the Japanese reactors, from MIT Nuclear Science & Engineering
http://mitnse.com/

a_ray_in_dilbert_space said...

If I'm interpreting this incident correctly, the nuke plant shut down pretty much as designed. The problem was that the backup electrical power sources (both generators and batteries) failed. If so, wouldn't we add this to the long list of other nuke accidents ultimately attributable to human stupidity?

seamus said...

dhogaza said: Which has actually been happening for a couple if days, unless you accept the Japanese "we're cool" assessment vs. the US (invited) overflights showing highly radiative plumes above the reactors.

Except that was radioactivity beaming up from the spent fuel pools, not a plume of radioactive particles. In my silly head, "plume" conjures up big releases of radioactive materials such as the Chernobyl accident or an above-ground weapon test. Which we know hasn't happened. Sorry for the misunderstanding. I agree it's likely the extremely sensitive detectors are picking up xenon-133 from the Fukushima "plume". Xenon-133 is also produced from normally functioning plants however.

Xenon-133: Ambient Activity from Nuclear Power Stations
"The average activity of xenon-133 within and at approximately 100 kilometers from Albany, New York, from April to July 1975 was 2.6 picocuries per cubic meter of air. The source was gaseous effluents from boiling water reactors located in the northeastern United States. Its 5.29-day half-life makes xenon-133 an appropriate isotope to observe for the study of regional and hemispheric dispersion of pollutants."

@a_ray: yes, a "station blackout" is apparently considered one of the worst events for BWRs. Even though they have an incredible array of emergency cooling systems, loss of external power is a weak spot.

adelady said...

a-ray-i-d-s. "the long list of other nuke accidents ultimately attributable to human stupidity"

Humans design these things, then other humans build them, and others operate them, and others manage them - and others own the whole she-bang. Yet other humans are assigned responsibility to regulate and enforce the regulations.

Why people haven't yet worked out that some dangerous things are susceptible to the greed, silliness, stupidity, laziness and dishonesty of some people, regardless of their formal role, which thereby makes them even more dangerous is a mystery to me?

I won't worry about conscientious, diligent, intelligent, honest, sensible people - apart from the fact that we simply cannot guarantee that everyone involved is that kind of person.

seamus said...

dhogaza said: Which has actually been happening for a couple if days, unless you accept the Japanese "we're cool" assessment vs. the US (invited) overflights showing highly radiative plumes above the reactors.

Except that was radioactivity beaming up from the spent fuel pools, not a plume of radioactive particles. In my silly head, "plume" conjures up big releases of radioactive materials such as the Chernobyl accident or an above-ground weapon test. Sorry about the misunderstanding. I agree it's likely the (extremely sensitive) detectors are picking up xenon-133 from the Fukushima "plume". Xenon-133 is also produced from normally functioning plants:

Xenon-133: Ambient Activity from Nuclear Power Stations
"The average activity of xenon-133 within and at approximately 100 kilometers from Albany, New York, from April to July 1975 was 2.6 picocuries per cubic meter of air. The source was gaseous effluents from boiling water reactors located in the northeastern United States. Its 5.29-day half-life makes xenon-133 an appropriate isotope to observe for the study of regional and hemispheric dispersion of pollutants."

@a_ray: yes, a "station blackout" is apparently considered one of the worst events for BWRs. Even though they have an incredible array of emergency cooling systems, loss of external power is a weak spot.