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What the Spent Fuel Pools Might Mean (It’s Probably Not What You Think)

March 17th, 2011 16 comments

Screencap from the entry movie from pro-nuclear activist William Tucker's site TerrestrialEnergy.org.

You are going to have to forgive me when I hurl a few rejoinders in the coming paragraphs. I imagine my gallows humor may strike many of my readers as just about as dry at the spent fuel pools ABOVE Fukushima I’s reactors #3 and #4 — yes, that’s right, TWO spent fuel pools, not just one, in which the “risk of re-criticality is not zero.” And they’re above the reactors.

Above.

First, Richard Black of the BBC, in a sidebar to this article:

The targets were cooling ponds situated above the reactors, which store fuel rods. The ponds in buildings 3 and 4 – and possibly more – are certainly short of water, possibly completely dry.

[Link.]

I’m sorry, did you miss it? Black said:

The targets were cooling ponds situated !!!!!!!!!!!!ABOVE!!!!!!!!!!!!!!!!!! the reactors, which store fuel rods.

…Emphasis mine.

I”m just curious. Does that sound like an awesome idea to anyone other than me? Or did nobody else get their feelings hurt by being ridiculed publicly by nuke-jocks for asking whether it was true that the China syndrome was possible. In the so-called China syndrome, an out-of-control nuclear core burns through the floor of the containment vessel and the floor of the containment building and into the basement. It’s a theoretical construct that doesn’t happen, won’t happen, and can’t happen. “Three Mile Island proved” it can’t happen, because the melted slag is not hot enough to burn through the bottom of the containment vessel.

But, for what it’s worth, in the meltdown of a core in which the containment vessel is breached (that’s different than the containment building), the melted core ends up in the basement. It did at Chernobyl. It formed an “elephant’s foot” in the basement under the reactor. It didn’t at Three Mile Island, because the containment vessel wasn’t breached. Nuke pundits say that TMI was “proof” that a meltdown can’t glorp out the bottom of the containment vessel, which I strenuously disagree with. It’s not “proof,” it’s a very strong indication. But that’s the only model we have for the meltdown of a large civilian water-moderated reactor, so it’ll have to do. Fukushima is not another Chernobyl because its ten reactors are water moderated and have containment buildings (which Chernobyl did not, and which the spent fuel pools do not).

At Fukushima, by the way, they did do something else the Soviets didn’t. They placed the spent fuel pools above the reactors. Which is 142 tons of spent fuel rods in the case of #4 reactor. As best I can tell (and I’m guessing), that’s something like ten-ish times the size of an active core.

Did I mention spent fuel pools don’t have a containment vessel, as such. I mean…sure, they’re contained. But they’re not supposed to ever go critical, so they aren’t designed to withstand criticality. The floors of the containment structures of the spent fuel pools aren’t designed to sustain any fuel rods at all undergoing active criticality, let alone meltdown.

I’m not saying a meltdown could happen with spent fuel — I don’t know. But I certainly don’t see how it could. But then, I don’t really see how it could go critical. This stuff is spent. It has 1% the fertility of new fuel. Right?

New Scientist confirms the fact that the spent fuel pools are above the #3 and #4 reactors, and both of them are undercooled — possibly completely dry.

Okay, that’s bad design, but back to why the spent fuel might enter re-criticality, which is something nuclear engineers know just doesn’t happen, which is why it’s so strange that Tepco, who’s been talking bullshit about “don’t worry” this and “no big deal” that from the start, now can’t shut up about it.

Again, how’s this happen? It doesn’t. It’s supposed to be impossible. Anyone with even the most rudimentary knowledge of nuclear engineering knows that re-criticality in a spent fuel pool just doesn’t happen. It just doesn’t. So why is Tepco saying it might, or more accurately saying the probablility of it “is not zero,” which from my experience of Tepco over the last week tells me it either probably has, or is probably going to, or they haven’t got the foggiest idea how likely it is?

Incidentally, the first spent fuel pool reported to be in trouble was Reactor #4. Reports from NHK and Nikkei led me to believe there were two blasts, as there were said to be two holes in the #4 building. That’s probably important, so if anybody out there has the reference, please let me know.

Here Is What’s Happening In The Spent Fuel Pools At #3 and #4 Reactor

  • The spent fuel rods are heating up. Enough to be a problem.
  • Since they put out something like 1% of the heat of active fuel rods, or less, maybe way less, that is kind of bizarre.
  • The structures that keep the spent fuel rods away from other spent fuel rods were apparently damaged in the explosions at #4 (and now #3).
  • That means the spent fuel rods are closer together than they ought to be.
  • That the means the chance of criticality is increased (the closer fissionable material gets to other fissionable material, the closer the chance of criticality).
  • The rods must be cooled.
  • The spent fuel pools are sufficiently “hot” (radioactive) that doing that’s difficult because of the risk to workers.
  • So they’re spraying it from helicopters, which isn’t working. It didn’t work at Chernobyl either, incidentally.
  • Fissionable nucleii put out neutrons, which results in other fissionable nucleii grabbing them, becoming unstable, and fissioning. That puts out heat, creates other neutrons, and you have a chain reaction, which is called a criticality.
  • Neutrons cannot be captured by fissionable nucleii if they are moving too fast.
  • Water is the best way to cool the rods.
  • Water slows neutrons.
  • Water therefore makes it more likely that a given neutron emitted by one atom will be captured by another fissionable nucleii, and fission.
  • Tepco is adding boric acid to the water to keep that from happening.
  • Tepco executives appear to be a bunch of third-graders high on bath salts.
  • No offense is intended to any third-graders reading this. And, incidentally, would you like to take over crisis management in the nuclear industry?

Here’s What I Don’t Know

  • I have no idea if the fuel rods “must be cooled” because they might otherwise reach meltdown temperatures. I don’t know the melting point of MOX fuel, but it’s lower than uranium fuel.
  • That would be really hot.
  • That seems like it would have to be completely impossible.
  • Remember, spent fuel rods, depending entirely on how old they are, put out something like 1% or less (maybe way less) of the heat that active fuel rods do.
  • So their melting under their own heat would be completely impossible.
  • Unless they reach criticality.
  • If the spent fuel rods achieve re-criticality, then they will be generating their own heat.
  • Except. Um…
  • To my knowledge, this time there will be no control rods. At all.
  • There will also be no containment structure.

There would be no control rods because spent fuel pools are not designed to need them. They don’t ever go re-critical, remember? There’s no containment structure because spent fuel pools don’t need them. Remember?

Here’s What Happens If That Happens:

  • I don’t know, and I don’t know the likelihood of it happening. I also don’t know the magnitude of the problem if it does. However:
  • The size of the spent fuel pool at reactor #4 is 142 tons; I don’t know about the one at #3.
  • I am presuming from news reports that this mass estimate is the total weight of the fuel rods, which includes the whole assembly; it’s not just the fuel; it’s also cladding, which is zirconium alloy, and other stuff that keeps the fuel rods together.
  • I don’t know if a given spent fuel pool is uranium or MOX. Various reactors at Fukushima were loaded with either uranium or MOX — and I have no guarantee that the pools at #3 and #4 only include spent fuel from those reactors, so there’s no way (from here) to find out if we’re talking uranium or MOX in the #3 and #4 spent fuel pools.
  • On short notice, I can’t find a good reference for what the mass is for the MOX fuel in active core of a Fukushima-sized reactor.
  • The best I can do is to guess, based on megawatt output and my meager reading in uranium metallurgy, that IF all the reactors at Fukushima were uranium-fueled reactors, we would be talking about something between 5 and 10 kilograms for a single active core.
  • That’s 5 to 10 kilograms.
  • They’re not uranium-fueled reactors; some are mixed uranium and plutonium (MOX). (Plutonium is far more toxic, by the way, though some of its fission products are ultimately the really dangerous stuff). Knowing little about metallurgy, I can guess at the uranium because uranium’s a whole lot simpler to understand. In any event, plutonium is denser than uranium. It is machined differently. MOX fuel is a different thing entirely. Etc. etc. etc.
  • So it’s a complete stab in the dark when I say that the “nightmare scenario” of a single core melting down completely was a scenario involving something like one-tenth to one-fifth the amount of nuclear material in the #4 spent fuel pool.
  • Again, these are not active uranium or MOX fuel rods. They are spent. They put out 1% of the heat of active rods. They have a lot less propensity to fission.
  • That said, Tepco sure does seem worried.

Again, this is not supposed to happen, which is why the fact that’s happening is a far bigger concern than if, say, the core just melted down — which everyone has known was a (remote) possibility in any reactor since the 1940s.

What’s so important about any of this? The magnitude of the potential problem, and the dishonesty Tepco has shown in the way it’s dealing with us. Depending on what caused the Reactor #4 explosions, it may also represent a gross malfeasance on Tepco’s part well beyond what we know about so far.

Here’s why.

How The Hydrogen Was Produced

Reactor #4 was shut down at the time the earthquake and tsunami happened. Three of the other five reactors at Fukushima I (Fukushima Daichi) were active. Those three all experienced hydrogen explosions. Though I first heard about it from anti-nuke activist Karl Grossman, who appears to be either a lying wing-nut or a confused wing-nut, he was right on one thing — the hydrogen appears to have come from the interaction of zirconium alloy (which is used in the fuel rod cladding, or shell) with very hot water, wherein zirconium oxide, hydrogen and oxygen are produced.

I read someone on a wing-nut board — who seemed to not be quite as nutty as the rest — suggest that those hydrogen explosions couldn’t happen in the case of simple decay heat if the reactors had been properly shut down. I don’t know; I’m not a nuclear engineer. But I did hear an engineer say something very interesting — again, uncited, unquoted, wing nut, take it as a friend-of-a-friend story and PLEASE DEBUNK IT if you’re a nuclear engineer.

The speculation is this: Was the rapidity with which such a large quantity of hydrogen was generated de facto proof of meltdown. That would mean all three active reactors at Fukushima Daichi were in meltdown very early in this process. Tepco then either didn’t tell us, or didn’t know.

Again, there’s probably a reason why the production of hydrogen is not de facto proof of meltdown. Nuclear advocates, and I count myself among you, God help me, I encourage your rude, hateful, trolling, aggressive, blatantly ridiculing opinions in the comments, correcting me, as I’m not a chemist.

For all I know, the hydrogen could have been produced by another process. Both radiolysis and thermolysis have been mentioned, though they both seem unlikely. Radiolysis would be where neutron flux broke the bonds between the hydrogen and oxygen in water, creating gaseous hydrogen and gaseous oxygen. Thermolysis would be the same thing caused strictly by very high temperatures. The molecular bonds in water would only break down at something like 2,000 degrees Fahrenheit and above, I believe. Therefore, the zirconium reaction is a much simpler explanation. I believe that would also happen at something like 2000 Fahrenheit.

Which is almost exactly the melting point of metallic uranium. That’s 2075 degrees Fahrenheit.

Uranium oxide, however, the form used in MOX fuel, melts at a much higher temperature. But wait! Mix them together and you get something that melts at a lower temperature, at least according to one guy, the Japanese reactor designer who freaked everyone out a few days back:

At a press conference in Tokyo, Masashi Goto, who worked for Toshiba as a reactor researcher and designer, said the mixed oxide (MOX) fuel used in unit 3 of the Fukushima Daiichi nuclear plant contains plutonium, which is much more toxic than the fuel used in the other reactors.

MOX fuel is a mixture of uranium and plutonium reprocessed from spent uranium, and is sometimes involved in the disposal of weapons-grade plutonium.

[Masashi Goto] added that the MOX also has a lower melting point than the other fuels. The Fukushima facility began using MOX fuel last September, becoming the third plant in Japan to do so.

[Link.]

I don’t know that temperature, but I’m sure one of my intellectually brutal nuclear-advocate readers does. Sock it to me! For now, all I know is that it’s lower than the uranium fuel used in the reactors other than #3, but there’s no guarantee that the fuel in the spent fuel pool at #4 is ONLY fuel from #4. I don’t know how this crap works…for all I know, the spent fuel pool could be nothing but MOX.

Is that a suggestion — though very, very far from proof or even a scientifically-worthy indication — that if the spent fuel in the #4 pool is MOX, it melts at a temperature low enough that even spent fuel rods, if they were somehow experiencing re-criticality — as Tepco has admitted they might — could have generated it?

Because if it was, and if a lot of other things are true that I, as a non-scientist, non-nuclear engineer, can neither investigate nor rule out, then that wouldn’t just mean the #4 explosions could have been hydrogen.

It would mean that, at some point, the spent MOX fuel rods in Reactor #4′s spent fuel pool, said to be physically and scientifically unable to experience criticality, were damaged by the explosion in #3, forced into proximity — and experienced criticality, boiling off the water from the spent fuel pool garden hose, and generating hydrogen.

Which would mean the spent fuel pool experienced re-criticality a couple days ago.

Were the Reactor #4 Explosions Hydrogen or Machine Oil?

The structure that holds the spent fuel rods in the spent fuel pools at #4 may have been compromised by the explosion at reactor #4 and the explosion at reactor #3 — which is close by. However, the explosion at #3 preceded the explosions at #4. Therefore, the hydrogen reaction could have created the disruption of the containment structures at the spent fuel pool at #4 that would have created the possibility of criticality. If that happened, and for some reason (extremely unlikely in the annals of engineering) the spent fuel started melting early, as far as I can tell it wouldn’t have generated hydrogen because it wouldn’t have been hot enough. But as far as I can tell, spent fuel pools don’t go critical in the first place.

The initial explosion at reactor #4 was said by Tepco, the company that operates the plant, to be caused by machine oil, not hydrogen.

However, if it turns out that #4 was not machine oil, they were hydrogen, that’s a whole ‘nother ball game, indicating criticality may have been reached in the spent fuel pool without Tepco even knowing it.

Is Tepco Lying About The Cause of the Explosions at Reactor #4?

If the initial reactor #4 explosion WAS a hydrogen explosion, and originated with the spent fuel pool there rather than from the reactor itself, then that would (as I understand it) indicate — though absolutely not prove in any way, shape or form — that the spent fuel in the #4 reactor’s spent fuel pool was heating up to the point where the zirconium alloy fuel cladding in the fuel rods was reacting with water to form hydrogen.

That would be hot. Really hot.

A Last Word About How Speculative This All Is

Again, I’m still shocked that anyone’s talking about re-criticality. This still seems really unlikely, borderline impossible. That’s why it’s freaking everyone out that Tepco, which has so thoroughly covered its ass all along, is suggesting not just this extreme scenario, but this way-beyond-extreme scenario.

But then, this crap was in the BBC. This crap was in New Scientist. Tepco has been playing down the crisis from the start. They appear to have vastly underreported the events from early in the process. Now they’re talking about re-criticality in a spent fuel pool. They. Tepco. The nuclear industry.

My speculations sound crazy to many of you, I’m sure. But Tepco’s already blown the roof off of all projections — and everything any of the pro-nuke trolls have said — by saying that the spent fuel can reach re-criticality to begin with. Which, in case you forgot, they already said.

I gather that, to a nuclear engineer, this is a bit like if the Air Force sat all its pilots down one day and said, “We were just messing with you. Those weather balloons really are alien spacecraft.”

Which, quite frankly, I’m half-expecting Tepco to do, any minute.

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Fake Fallout Map is Fake — But Real Map Is Real

March 17th, 2011 No comments

Back on the 14th, Snopes debunked a fraudulent map circulating on the net, purporting to be from the Australian Radiation Services. That is a real organization, but has nothing to do with the above purported “fallout map,” which looks a little like something that would show up on the inside cover of a Gamma World reboot.

The “rad” is an obsolete unit of absorbed radiation dose. The unit currently in use is the “roentgen-equivalent man,” or rem, in the United States, and the sievert in most other countries. The use of the rad as a unit can often be a tip-off that any information you’re getting about radiation is fraudulent or pseudoscientific, which has been true for a while now.

Obviously, since doses above 1000 rads are likely fatal, and doses above 200 rads usually cause serious illness, this map is intended to freak you out. Did it work?

In any event Monday the 14th (or even earlier, over the weekend) would have been a ludicrous time to begin making projections about how much radiation would cross the Pacific, especially since nobody’s 100% sure even now. It’s almost certain to be irrelevant in medical terms, however.

The REAL projection, from the Comprehensive Test Ban Treaty Organization, doesn’t include amounts of radiation. It also has these wonky dots that represent the Organization’s monitoring stations. That map appears to be entirely un-fraudulent and was obtained by the New York Times despite its not being released to the member governments but not to the public by the Organization — probably in an attempt to avoid causing panic (way to go!!!)

The Australian Radiation Service puts the following disclaimer at the top of its site, in red:

DISCLAIMER: Australian Radiation Services is aware of information about radioactive contamination being spread from the Japanese nuclear reactor incident released under the ARS logo and name.  We wish to be clear that this information has not originated from ARS and as such distance ourselves from any such misinformation.

[Snopes Link.]

[Australian Radiation Services Link.]

The real projection is far less satisfying in visceral terms — see? Here is a screencap of it, and you can find the real interactive version at The New York Times, who loves you far more than the Comprehensive Test Ban Treaty Organization.

Screencap from the New York Times

Fukushima Plume to Reach Continental U.S. Friday

March 16th, 2011 No comments

Screencap from the New York Times

The New York Times just published a story in which it obtained the projected course of the radiation plume from Fukushima I plant.

If current weather holds, the plume is projected to reach the Aleutian Islands on Thursday (tomorrow) and California on Friday, but by the time it reaches the U.S. the effects should be detectable but not harmful.

This sounds 100% reasonable based on everything I know about the crisis, but to be fair, in coming to that conclusion, it’s my opinion the New York Times is meeting the US Government way more than halfway. The last NRC projection levels were from Sunday, before a whole lot of things happened.

The projection itself did not include information about radiation levels. Those come from the NRC, but are maddeningly unspecific and, most importantly, did I mention they are from Sunday?

I’m not suggesting there will be harmful health results from the plume. I can’t possibly know. I’m not a scientist or a doctor. But I sincerely doubt there will be any harmful effects. Everything I know about Fukushima and Chernobyl — which is the only real case to compare it to (since Fukushima long since left Three Mile Island behind) says there will not any detectable health results from the plume.

But wouldn’t it be awfully nice to hear that from the government the day before the plume hits the Aleutians? Which would have been today?

The projection of the plume’s path was generated by the Comprehensive Test Ban Treaty Organization, which “routinely does radiation projections in an effort to understand which of its global stations to activate for monitoring the worldwide ban on nuclear arms testing. It has more than 60 stations that sniff the air for radiation spikes and uses weather forecasts and powerful computers to model the transport of radiation on the winds.” The Organization declined to release the report from the Fukushima event, but it was distributed to its member states. The New York Times obtained the projection “through other sources.”

More from the Times:

Health and nuclear experts emphasize that radiation in the plume will be diluted as it travels and, at worst, would have extremely minor health consequences in the United States, even if hints of it are ultimately detectable. In a similar way, radiation from the Chernobyl disaster in 1986 spread around the globe and reached the West Coast of the United States in 10 days, its levels measurable but minuscule.

On Sunday, the United States Nuclear Regulatory Commission said it expected that no “harmful levels of radioactivity” would travel from Japan to the United States “given the thousands of miles between the two countries.”…

…[The] forecast shows that the radioactive plume will probably miss the agency’s monitoring stations at Midway and in the Hawaiian Islands but is likely to be detected in the Aleutians and at a monitoring station in Sacramento.

The forecast assumes that radioactivity in Japan is released continuously and forms a rising plume. It ends with the plume heading into Southern California and the American Southwest, including Nevada, Utah and Arizona. The plume would have continued eastward if the United Nations scientists had run the projection forward.

The chairman of the Nuclear Regulatory Commission, Gregory B. Jaczko, said Monday that the plume posed no danger to the United States. “You just aren’t going to have any radiological material that, by the time it traveled those large distances, could present any risk to the American public,” he said in a White House briefing.

Mr. Jaczko was asked if the meltdown of a core of one of the reactors would increase the chance of harmful radiation reaching Hawaii or the West Coast.

“I don’t want to speculate on various scenarios,” he replied. “But based on the design and the distances involved, it is very unlikely that there would be any harmful impacts.”

…In Germany on Wednesday, the Federal Office for Radiation Protection held a news conference that described the threat from the Japanese plume as trifling and said there was no need for people to take iodine tablets. The pills can prevent poisoning from the atmospheric release of iodine-131, a radioactive byproduct of nuclear plants. The United States is also carefully monitoring and forecasting the plume’s movements. The agencies include the Federal Aviation Administration, the National Oceanic and Atmospheric Administration, the Department of Defense, and the Department of Energy.

[Link.]

You will occasionally find wacky official-looking reports on the web that Chernobyl caused a million deaths. That is ridiculous. Sure would be nice to hear that from the government, though — but they’re busy being vague.

A somewhat less crazy assertion is that one million people were affected by the Chernobyl radiation. The World Nuclear Association, a pro-nuclear organization based in the UK, said that. Just to be agonizingly clear, this is what they said in their report on Chernobyl:

Subsequent studies in the Ukraine, Russia and Belarus were based on national registers of over one million people possibly affected by radiation. By 2000, about 4000 cases of thyroid cancer had been diagnosed in exposed children. However, the rapid increase in thyroid cancers detected suggests that some of it at least is an artefact of the screening process. Thyroid cancer is usually not fatal if diagnosed and treated early.

This is the most important part: Even if the amount of material and the radiation released were the same as Chernobyl, the areas comparable to Ukraine, Russia, and Belarus in this case are all over the Pacific Ocean. There are almost certainly people living there, but it’s apparently going to miss the part of the Pacific with a large(ish) number of islands.

Here’s what Wikipedia says about the distribution of radiation from Chernobyl; I glanced at the refs for them and they seem to be more or less on scale. Wikipedia:

Four hundred times more radioactive material was released than had been by the atomic bombing of Hiroshima. However, compared to the total amount released by nuclear weapons testing during the 1950s and 1960s, the Chernobyl disaster released 1/100 to 1/1000 the radioactivity. The fallout was detected over all of Europe except for the Iberian Peninsula….

…Contamination from the Chernobyl accident was scattered irregularly depending on weather conditions. Reports from Soviet and Western scientists indicate that Belarus received about 60% of the contamination that fell on the former Soviet Union. However, the 2006 TORCH report stated that half of the volatile particles had landed outside Ukraine, Belarus, and Russia. A large area in Russia south of Bryansk was also contaminated, as were parts of northwestern Ukraine. Studies in surrounding countries indicate that over one million people could have been affected by radiation….

That is the source of the the one million “affected by radiation” claim — they were all in Ukraine, Belarus, and Russia. The comparative area here is the Pacific Ocean, even if the amount of radiation and radioactive material were the same.

And you know, I’ve been thinking…

…Wouldn’t it be nice to hear all this from the government?

Fukushima Spent Fuel Pool Could Go Critical

March 16th, 2011 No comments

The BBC is reporting that the attention at Fukushima has indeed switched to reactor #4. Reactor #4 was shut down for maintenance before the earthquake struck. Now the problem is that spent fuel stored near reactor #4 is heating up, and they are unable to keep it under water. The pool, in fact, is entirely dry — which is not good news.

At a nuclear reactor, spent fuel rods are stored in a “spent fuel pool,” which is basically a reinforced pool with structures to hold the fuel rods in place and make sure they don’t get too close to each other. They are stored on site because of the complicated nature of disposing of spent nuclear fuel.

The fuel rods, which are highly radioactive, also stay thermally hot. They can potentially get hot enough to melt, in which case the structures keeping them together are compromised. That results in a release of radiation.

Bad news? Yes. Worse news? Tepco, the company that operates the plant, has told the BBC that the spent fuel rods may be about to go critical again.

What does that mean? It means that an active nuclear reaction could potentially start up again, which would heat the rods further, and create a much greater release of radiation. I am unclear on whether that means the entire spent fuel pool could potentially reach the melting point of zirconium alloy cladding and  the other containment structures that hold them in place to make sure they don’t get too close together and go critical. What that would mean is that the fuel and the rest of stuff that goes into fuel rods, and the stuff around the pool — would get so hot it would all melt together.

The thing is, all the commentators I’ve read are sort of scratching their heads. Nobody seems to be sure what Tepco is talking about, because the “re-criticality” (the nuclear chain reaction starting again) of the fuel rods in a spent fuel pool is just plain not supposed to happen. It’s not so much that it’s a worst case scenario — it’s worse than anyone seems to have thought was even vaguely possible.

In a CORE meltdown — not a spent fuel pool — once the core melts, it becomes difficult if not impossible to stop the reaction. It just keeps melting. It probably congeals eventually — at Chernobyl a giant “elephant’s foot” of corium was found in the basement, having oozed there. I have no idea if that is physically possible in the case of a spent fuel pool, but it sort of seems like all the people who seem to know specifics like that are busy deriding me for asking. To hear many pro-nuke bloggers say it, instead of asking questions like that I should be educating my friends on how safe nuclear energy is.

There’s about 142 tons of fuel, according to a Bloomberg story, in which Cambridge physicist Geoff Parks says that the above scenario, in which the fuel rods go critical again, is remote. The temperature required would be 2,200 Celsius — almost 4,000 degrees Fahrenheit. That’s roughly the heat of a meltdown.

How did the overheating happen? The lack of water. Pro-nuke blogger Rod Adams said in an earlier post that we should all calm the hell down about the spent fuel, because the amount required to keep the spent fuel pool cool was about equivalent to  a garden hose run for a couple of hours each day.

But how did it happen that the hot material can conceivably go critical again, pretty much the worst-case scenario for a spent fuel pool and one of those things we’ve been reassured over and over again by pro-nuke speakers, writers and bloggers is absolutely impossible? The spent fuel pools essentially consist of fuel rods stacked with material between them to ensure they don’t get too close together, with very strict limits on how many spent rods can be placed in a pool. Sometimes the pools get full, and they are then stacked closer together than is usually mandated, in that case, boron sheets are stacked between them.

OK…so…I have one last piece of very bad news: In the spent fuel pool at Fukushima I’s reactor #4, there is no containment structure. (The NRC chair told ABC News that “secondary containment has been destroyed,” but I believe this refers not to a full containment structure, since from what I can see there isn’t one.

There’s no containment structure for the spent fuel pool because the spent fuel rods properly stored put out only a fragment of the heat that active fuel rods do — something like 1% or less, maybe far less. So no problem, right?

Incidentally, the lack of a containment structure is one of the several chief matters that we’ve been told by the Pro-Nuke, Calm-the-Fuck-Down-Dipshit Commandos, was a problem at Chernobyl. The fact that all of Fukushima I’s six reactors (and the four at Fukushima II) have containment structures were trumpeted as proof that this would never become another Chernobyl.

It still won’t become another Chernobyl. Chernobyl was a graphite-moderated plant, very different than a water-cooled reactor like Fukushima. Chernobyl suffered a huge explosion while the reactor was fully active. The Chernobyl fire burned out of control for days. At Chernobyl the “corium” — nuclear material mixed with melted containment structure, machinery and reactor building — was visible from the air above Chernobyl, glowing red-orange. Notice how I’ve said Chernobyl over and over again? The reason is that I don’t want some sketchy content farm site-scrubber or, say, a dicey search engine like, oh, Google, or a scumbag panic-blogger to grab a teaser from this column and get the impression that any of these things are happening at Fukushima — they are not.

But you know what I would really like? I would like, when this is all said and done, representatives from General Electric, which built the plant, to sit down in front of the Japanese people and answer why it seemed like an awesome idea to build a storage pool for fuel rods without a containment structure.

Would it have driven their bid up $100,000 or something?

Or was it just, you know, not deemed necessary, because, as pro-nuclear bloggers love to remind us, this was a really big earthquake and who could have ever expected it, at the edge of a tectonic plate in one of the most active earthquake zones on Earth?

See, the nuclear industry planned ahead, all right. It planned for an earthquake to hit Japan.

It just didn’t plan for a big earthquake to hit Japan.

For that, it wants a pat on the back.

How about a swift kick in the nuts, instead?

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MIT Damage Control and Josef Oehmen’s “Why I Am Not Worried” About Fukushima

March 16th, 2011 2 comments

There’s  an essay making the rounds by Dr. Josef Oehmen of MIT. It’s called “Why I’m Not Worried About Japan’s Nuclear Plants.” I’ve now seen it posted about 10 times to various message boards discussing the Fukushima I disaster — often by what appear to be trolls, and often with laudatory remarks. In it, Oehmen rails against the media for inaccurate reporting. It’s been reposted on hundreds of message boards, picked up by Discover Magazine and The Telegraph, and I’m quite confident it’s been emailed all over the place.

The piece is presented as if Oehmen’s being at MIT means he’s a nuclear expert because people at MIT are, y’know, SMART. The piece “went viral,” including being posted on a site run by Siemens, a major nuclear-industry powerhouse. In it, Oehmen says that there has not been and will not be a significant release of radiation from the Fukushima I site.

Justin Elliot does a great and thorough debunking on Salon, but here are the high points. Not only is the piece days out of date at this point, but it’s fraudulent twaddle to begin with. It’s been posted, and Oehmen appears to have allowed it to be posted, with the strong implication that his being an “MIT scientist” gives him expertise in this issue. It doesn’t.

The essay was written before releases of radiation had been confirmed, but since some earlier radiation accident at the MIT lab rendered Doctor Happy capable of predicting the future, he may have gotten a bit confused about the benefits of being able to read by yourself at night (it does save on the  power bills, that’s for sure).

The essay, now posted to a site maintained by MIT’s nuclear engineering department, has been modified. Says Justin Elliott at Salon:

So does Oehmen actually work at the Massachusetts Institute of Technology? Yes. But not in the nuclear engineering department. He works at an entity called the Lean Advancement Initiative, which focuses on business management issues. Is he a “research scientist”? Yes. But, again, not in any nuclear field. Oehmen’s research focuses on “risk management” with an eye to helping companies “take entrepreneurial risks.” He writes papers on things like “Human Resource Management in China.”

I e-mailed Oehmen to ask if he stands by the claims in the post. He referred me to the MIT press office, which in turn told me that Oehmen is not doing interviews.

An updated version of Oehmen’s blog post is now being hosted at a website set up by students in MIT’s Department of Nuclear Science and Engineering. Oehmen’s crucial claim — that there was no chance radiation would be released — has been cut. The title, which was originally “Why I am not worried about Japan’s nuclear reactors,” has been changed. An introduction pointedly says, “Note that the title of the original blog does not reflect the views of the authors of the site.”

[Link.]

Oehmen’s expertise in the nuclear industry is that his father worked in the German nuclear industry. And his area of expertise is…is that supply chain management?!?? I’m not totally sure what any of this means in the version of English spoken by non-academics. He sounds like a business/economics guy, I visited the damage-control site MIT set up.

I found Oehmen’s list of publications, which is all very educational but it’s not his CV. His bio basically spells out his academic studies, and indicates that he did study mechanical engineering, which is in no way shape or form nuclear engineering. It’s all a little obfuscating because high-end academic shit is frankly so filled with buzzwords as to be basically incomprehensible to us simple cavemen.

An actual CV would be more helpful.

So I hit the link for Oehmen’s CV, which is right there on the MIT damage-control site. I wanted to find out what his undergraduate and graduate degrees are in, specifically. guess what I got? THIS.

That’s right, it’s the same damage-control page — a fail-safe loop, leading me back to asking “Who’s on first?” Simple technical error, or has Oehmen’s actual CV been taken down? Who knows? Who cares? Why bother?

This one is actually getting tagged not just with “accidents,” just with “hoaxes.” MIT, an institution for which I have enormous respect, should never be allowed to live this one down.

[Salon Link via Daphne Gottlieb.]

Status of All 10 Fukushima Reactors

March 15th, 2011 2 comments

Nikkei.com is reporting that damage to the fuel rods at the #1 reactor at Fukushima I is 70%, not the 43% previously reported, and 33% of #2′s fuel rods have been damaged. Meanwhile, #5 and #6 are overheating, but they are claimed to be under control — even though #5 has lost is coolant system.

Over at my Facebook page, on hearing that news about #5 and #6, a friend asked the question, “How many do they have, anyway!?”

The answer is six, at Fukushima I, but there are four more at Fukushima II.

Of those ten reactors, eight have failed to operate as planned, though only 3 (actually? probably? possibly? maybe?) experienced core meltdown.

At Fukushima I, only #4 reactor, which was shut down before the earthquake, isn’t having a problem with the cooling of its reactor as such. And that one is where the spent fuel rods caught fire and explosions blew not one but two 8-meter holes in the building. So…it’s not entirely accurate to say that 9 out of 10 of the Fukushima plants had trouble. It’s 8 out of 10, plus a spent fuel pool.

Incidentally, I saw a BBC report that the #4 reactor fire might have been caused by machine oil, not hydrogen like the other explosions. Hydrogen is generated by steam reacting with the zirconium in the zircaloy (zirconium alloy) fuel cladding that holds the fuel rods.

Here’s the status, as I know it, gleaned strictly from the news.

Fukushima I (Fukushima Daichi):

Reactor #1 has had either 43% or 70% of its fuel rods damaged. That DOES NOT mean a 43% or 70% meltdown. A partial meltdown was confirmed in reactor #1, but it’s not clear how much melted down.

Reactor #2 has had 33% of its fuel rods damaged, but a meltdown hasn’t been confirmed. Reactor 2, however, did have a breach of the containment vessel confirmed, which is probably more significant than a meltdown.

Reactor #3 is where, just a few minutes ago, white smoke was seen rising. Nobody knows why. Earlier, Reactor #3 had a hydrogen explosion. The white smoke could be steam (in fact, it probably is), which would be expected. It could potentially be radioactive. It is not known if #3 suffered a partial meltdown or not.

Reactor #4 is the strangest animal. The reactor itself appears to be fine. It was shut down for maintenance at the time of the earthquake. The problems there come not from the reactor itself but from the cooling system on the spent fuel rods that are stored in what’s called a spent fuel pool at #4. The spent fuel rods are still very hot, both thermally hot and radioactive, and you have to keep water circulating over them in order to keep them cool. Don’t worry, though; former US Navy nuclear engineer, nuclear entrepreneur and pro-nuclear blogger has been the voice of reason throughout the crisis when it comes to the fuel rods. In an article in his blog Atomic Insights, he says he talked to his friends, who said that very little water is required to keep the spent fuel pool cooled off. Here’s what Adams wrote:

Apparently there are now “experts” who are trying to get people up in a tizzy about used fuel pools. I have exchanged private email with some friends who have operation experience at similar types of plants as those at Fukushima Daiichi. In their opinion, it is possible to keep used fuel pools cool enough by simply refilling them with water every once in a while. We talked about using fire hoses and one more numerically inclined contributor to the discussion said that a typical garden hose would provide a sufficient quantity of water in just a couple of hours each day.

[Link.]

…which is probably why there were not one but (apparently) two huge explosions at the #4 reactor, big enough to blow not one but two 8-meter holes, apparently, in a concrete structure. I say “apparently” because the NHK reports are sort of confusing — I’m not entirely clear if there were one or two explosions at #4. NHK released a photo of the damaged #4 structure, incidentally. Apparently these folks couldn’t find a garden hose.

The “experts” link that Adams objects to above goes into a sign-in-only article at the New York Times, so I have no idea who the hell is pissing him off. But surely, he wouldn’t have to cast his net very far to find an ill-informed media pundit spreading unscientific misinformation.

For instance, news agencies are reporting that the #4 spent fuel pools are the “main” problem now, which I see absolutely no indication of. I’m not sure where they got that; maybe they made it up. Or maybe it’s a red-herring created by the release of the photo of the damaged #4 structure. Who knows?

Incidentally, Rod Adams headlined that post of his reminding us that it is always wrong to panic, which is surely good advice. Panic never results in anything good happening.

But Adams reminded us at the outset of his post that this happened as a result of “an enormously powerful earthquake followed by a higher than expected tsunami.” “Higher than expected”? I’m the first one to admit I don’t know jack about uranium or plutonium metallurgy, cooling systems, or radiation. But I live in California. I know a small amount about earthquakes. “Higher than expected”? Does Adams know anything about tsunamis?

Anyway, get ready for some good news! It comes from reactors #5 and #6. Until very recently, there had been no problems at #5 and #6, which were shut down for a routine inspection before the earthquake. At last report, they were both overheating “slightly,” whatever that means. Then the c0olant system at #5 failed. Tepco said they can re-route the coolant system of #6 to cool down #5, too. since #6 seems to be the only reactor at Fukushima I with a working coolant system.

Sadly, we’re not quite done yet. There is a second Fukushima facility.

Fukushima II (Fukushima Daini):

Fukushima II, or Fukushima Daini (Fukushima I is Fukushima Daichi) is 11 kilometers away. Fukushima II has four reactors. Following the tsunami, three out of four of them were placed in emergency status. Those three had problems with their cooling systems and residents were evacuated. Those three had reached “cold shutdown,” in which the cores were at 100 degrees centigrade or lower, about 34 hours after the catastrophe, according to World Nuclear News:

The power plant’s four boiling water reactors stopped automatically on last week’s earthquake. At unit 3 the shutdown appears to have gone exactly as expected, with no systems damaged by the huge earthquake or tsunami. It went from power production to cold shutdown – where coolant water is at less than 100ºC – in about 34 hours.

All the reactors have remained safe, but damage to the emergency core cooling systems of units 1, 2 and 4 led to the announcement of emergency status. Those reactors used their a secondary system, the make up water condensate system, and this was used to maintain coolant levels above the reactor core. An additional emergency notice came from unit 1 concerning the temperature of a suppression chamber, which reached 100ºC after some time.

The plant then continued in a relatively steady state throughout 12 March, with coolant levels always maintained but a high level of attention from engineers. Units 1, 2 and 4 were prepared for potential pressure release, but this was never required.

[Link.]

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Fukushima I: Water Level Falling at #5, Second Fire at #4, #1 has 43% of Fuel Rods Damaged; Japanese Gov’t Raises Permissible Radiation Level;

March 15th, 2011 No comments

Image of Fukushima I #4 Reactor Building, from NHK.

At a news conference Wednesday Japanese Time, Tokyo Electric Power Company (Tepco), the company that runs the Fukishima I site, released the photograph at right of the #4 reactor building. IT shows a hole on the fourth floor about 8 meters across.

Which is to say, it doesn’t show anything. The damage to the building, while far from irrelevant, is not the point. Tepco is pulling a CYA again, stalling for time, releasing a photo that doesn’t show anything significant, while the water level has been reported falling at #5 reactor, there’s been a second fire at either #4 reactor or the spent fuel pool there — it’s not clear which — Tepco confirmed that 43% of the fuel rods are damaged in reactor #1, and the Japanese Government raised by 150% the total radiation that workers remaining behind at the plant could legally be exposed to. Those workers are, clearly, at significant risk at this point. I still hope, though I certainly don’t trust, that the claims from American nuclear bloggers that the workers are surely following adequate protection procedures. But if they were, I imagine the number of millisieverts allowed wouldn’t have been more than doubled.

The important questions, of course, are about the containment vessels on all four reactors, and the spent fuel pool at #4. The information on that count coming from Tepco and the Japanese government is still stunningly vague. In that context, releasing this photo is a way to put out information without putting out any information. Thanks, guys.

BBC was reporting there had been “four explosions” total, so I guess I missed one. I thought it had been “three explosions and a fire,” the fire being at he spent fuel pool by reactor #4, not the reactor itself — but then, here’s #4 with a hole blown in the side of the building. Hey, an explosion here, an explosion there; sooner or later you’re talking real damage.

But there’s also been a second fire at the #4 reactor — one that went out on its own — and NHK, as far as I can tell, appears to be reporting a second 8-meter hole in the outer wall. .

Another 8-meter square hole was also confirmed on the outer wall of the building. Both appeared after an explosion early on Tuesday.

An ensuing fire near the 4th floor reportedly later went out on its own.

Flames were also found spewing from the building early Wednesday, but the utility company said they were no longer visible half-an-hour later.

[Link.]

NHK also reported about two hours ago (7 p.m. California time Tuesday night, 3 a.m. Wednesday GMT):

At the quake-stricken Fukushima Daiichi nuclear power plant, it is feared that the fuel rods in two of its reactors are being rapidly damaged as they remain exposed due to the failed injection of coolant.

Tokyo Electric Power has estimated the extent of small holes or cracks in the fuel rods, based on the amount of radioactive material in the coolant.

It says 43 percent of the fuel rods in the No.1 reactor were possibly damaged at 1 PM on Tuesday, but the ratio had increased to 70 percent by 3:25 PM.

At the No.2 reactor, the ratio rose to 33 percent from 14.

In both reactors, the coolant levels are low, exposing the fuel rods. Sea water is being pumped into the reactors to cool them down, but the coolant level remains low, creating the risk of a meltdown.
Damaged fuel rods would leak radioactive material.

The pressure inside the reactors is sinking and Tokyo Electric Power is monitoring the data carefully while continuing to pump more sea water.

[Link.]

Meanwhile, the water is falling at #5 reactor — which had reportedly been stopped before the earthquake, for a routine inspection. However, it is still experiencing significant decay heat, and its coolant levels are falling. Importantly, the fuel rods at #5 are still under water. Here’s NHK:

At the time of the quake, nuclear fuel rods were already in the reactor and workers had to circulate water to cool them down.

But the tsunami damaged a diesel generator for circulating the coolant, allowing the pressure in the reactor to rise.

Workers opened a valve to reduce the pressure.

But the procedure allowed water to evaporate from the valve.

As of 9 PM on Tuesday, the water level was 2 meters above the fuel rods. That was 40 centimeters lower than 5 hours earlier.

The Agency says it can adjust the water levels by using the No.6 reactor’s generator, which wasn’t damaged by the tsunami. Workers are currently pumping water into the No.5 and No.6 reactors.

[Link.]

Meanwhile, the government has lifted the level of radiation that workers can be exposed to. It was apparently previously 100 millisieverts:

The health and labor ministry says that it raised the limit by a factor of 2.5, to 250 millisieverts, in cases of emergency.

The measure was adopted to secure enough time for workers at the power plant to engage in operations such as cooling down of the reactors.

Radiation above 250 millisieverts is said to cause health problems such as a temporary reduction in the number of white blood cells….

…The ministry explains that the measure was necessary to prevent a nuclear disaster. It says the international radiation limit is set at 500 millisieverts. It adds that medical experts have no clear knowledge about whether radiation of 250 millisieverts or lower will cause health damage.

The sievert is a dose-equivalent measurement that attempts to measure the radiation dose to human tissue. It is a measure of actual dose, not dose-per-time.

The sievert is different and considered more biologically significant than the absorbed dose, which is measured in units called grays. The “roentgen equivalent man” is still what tends to be used in the United States, though everyone’s supposed to be switching to sieverts. The rem measures the same thing as the sievert and is what the U.S. used throughout the Cold War, so some people may be more familiar with rems. One sievert is 100 rems; a millisievert is therefore a tenth of a rem.

The lowest clearly-carcinogenic dose is 100 millisieverts. 1000 millisieverts in one hour is enough to cause acute radiation sickness.

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What Three Mile Island “Proved” About Meltdowns

March 15th, 2011 No comments

Screencap from the entry movie at William Tucker's site, TerrestrialEnergy.org.

In an opinion piece from March 14, William Tucker writes some good stuff and some bad stuff about Fukushima in the Wall Street Journal. Tucker’s book is called Terrestrial Energy: How Nuclear Power Will Lead the Green Revolution and End America’s Energy Odyssey. In short, he glows green.

The main point Tucker makes is that the Generation III reactors that have been designed for future use in the United States are safer than the Fukushima reactors, which are Generation II. ALL existing civilian plants in operation in the U.S. are Generation II, the same generation as Fukushima. The Generation III reactors have been held up at the NRC for years, because of political opposition to nuclear power. The probable result of that is that nuclear power in the United States today is less safe, not safer, than if those Gen-III plants had been developed.

For the record, the Generation III plants reportedly eliminate the central flaw of the design of Fukushima — and every other Generation II plant — which is the lack of a fail-safe in coolant circulation. A fail safe is a system that, in the case of an event, fails into a safe state rather than a hazardous one.

In other words, the failures at Fukushima are in no way directly associated with using uranium or MOX fuel to heat water — that’s what these damn things are designed to do. The flaw is in not being able to maintain the coolant circulation in the event of a catastrophic disaster like this one. The Generation III plants eliminate that problem with a design that keeps water circulating in the case of a shutdown.

I’m with Tucker on several points, most importantly that the press needs to stop forecasting disaster, and that (once again!!) this is not Chernobyl and it’s not going to be.

But I have to say yet again — and I feel like I say it constantly — that the time for nuclear advocates to call for development of more nuclear power plants is AFTER the Fukushima events are under control. Which will be soon, I feel confident, but in the meantime STFU about building new power plants.

In any event, here’s Tucker:

Once the reactor has shut down, there remains “decay heat” from traces of other radioactive isotopes. This can take more than a week to cool down, and the rods must be continually bathed in cooling waters to keep them from overheating….If the pumps are knocked out in a Generation II reactor—as they were at Fukushima Daiichi by the tsunami—the water in the cooling system can overheat and evaporate. The resulting steam increases internal pressure that must be vented. There was a small release of radioactive steam at Three Mile Island in 1979, and there have also been a few releases at Fukushima Daiichi. These produce radiation at about the level of one dental X-ray in the immediate vicinity and quickly dissipate.

If the coolant continues to evaporate, the water level can fall below the level of the fuel rods, exposing them. This will cause a meltdown, meaning the fuel rods melt to the bottom of the steel pressure vessel.

Early speculation was that in a case like this the fuel might continue melting right through the steel and perhaps even through the concrete containment structure—the so-called China syndrome, where the fuel would melt all the way to China. But Three Mile Island proved this doesn’t happen. The melted fuel rods simply aren’t hot enough to melt steel or concrete.

…None of this amounts to “another Chernobyl.” The Chernobyl reactor had two crucial design flaws. First, it used graphite (carbon) instead of water to “moderate” the neutrons, which makes possible the nuclear reaction. The graphite caught fire in April 1986 and burned for four days. Water does not catch fire.

[Link.]

Right, right, and right, on the decay  heat, the Gen II cooling pumps, and the steam venting. His comment about the dental X-ray is red herring-fueled propaganda; the radiation release at Fukushima is probably not over and has not been evaluated in the calm following the storm. More importantly, information coming out of Japan has been spotty. It’s ludicrous to claim he knows how much radiation has been released, yet.

Here’s where he’s misrepresenting the facts:

Early speculation was that in a case like this the fuel might continue melting right through the steel and perhaps even through the concrete containment structure—the so-called China syndrome, where the fuel would melt all the way to China. But Three Mile Island proved this doesn’t happen. The melted fuel rods simply aren’t hot enough to melt steel or concrete.

[Link.]

Hell’s bells! Did this guy go to fourth grade? That’s the kind of science that gave us spontaneous generation of frogs from grain!!

Three Mile Island did not “prove” anything. Three Mile Island was a single case. Science “proves” things by repeated experimentation, not individual cases thirty years apart. Even then, in the case of very speculative situations with very small numbers of cases to draw on, science tends to “demonstrate” things, not prove them. Experimentation, modeling, evaluation of real-world results — those are all very important. All of those have been done in the case of building nuclear power plants.

But you don’t “prove” things by pointing to a related but certainly not identical situation thirty years ago! Just because we (thankfully!!) don’t have a whole pile of other real-world cases of this magnitude doesn’t mean you get to extrapolate from the only case that even smells vaguely like this!

Core meltdowns at civilian power plants are (again, thankfully) events so fantastically rare as to be utterly individual. The bottom of the containment vessel at Three Mile Island was not breached despite a significant amount of the core melting. As pro-nuclear people told us again and again and again at the beginning, Fukushima is not Three Mile Island or Chernobyl. Only now…Tucker is trying to tell us that it’s, oh, you know, still not Chernobyl, but it IS Three Mile Island.

Except it’s not Three Mile Island, and implying that it is is beyond ludicrous. Three Mile Island did not “prove” that the containment vessel could not be breached. It established only that it was not breached in that case. That’s an important data point. That’s a really important data point. But it doesn’t “prove” the floor of the containment vessel won’t breach.

Especially since the single containment vessel that contained the partially melted core at Three Mile Island was not leaking water. One of the cores at Fukushima is.

Am I saying that if there is a 100% core meltdown in all three cores at Fukushima — a highly, highly, highly unlikely scenario — the containment vessel will be breached? Does it mean the China Syndrome will happen? Will the melted corium hit groundwater and cause an explosion? Hell, no, it doesn’t mean any of that! It doesn’t mean anything!

In fact, Three Mile Island suggests that the melted core may not, in fact, breach the bottom of any of the containment vessels, even if there is a 100% core meltdown in all three cores (again, extremely unlikely). The China Syndrome appears extremely-extremely unlikely, for reasons of basic physics even when you do have molten metal that generates its own decay heat. Decay heat is not the heat from active chain reactions, which would be happening if the control rods had been blown to smithereens as at Chernobyl.

Is that heat less extreme than it was at Chernobyl? Hell yes, without question. Is it hot enough to melt steel? Nobody knows with absolute certainty, but probably not. It’s almost certainly impossible that the core would be hot enough to melt the thick steal of the containment vessel. But nobody knows with absolute certainty. It hasn’t been “proven.”

As Rod Adams, a highly (to me) abrasive pro-nuker but a reasonably rational nuclear advocate when he lets himself be, put it:

At TMI [Three Mile Island], the widely predicted and discussed “China Syndrome” did not happen, even though 20-30% of the core melted and slumped to the bottom of the pressure vessel. That melted corium froze again once it contacted the thick metal walls – the maximum measured penetration was just 5/8ths of an inch. Anyone who has ever watched as welder employs a torch to cut through a thick steel wall will understand just how much concentrated power it takes to melt several inches of steel. Avoiding the China Syndrome was not a matter of luck – the scenario is imaginary and only works in fiction. Physics and material science make it impossible.

[Link.]

My opinion is that Adams is carrying the existing information a bit far in coming to that conclusion that “Physics and material science make it impossible,” but at least he doesn’t use the P-word.

Adams is not a scientist; he was trained as a nuclear engineer in the U.S. Navy, so I trust his gut feeling on this way more than I trust any amount of scientific understanding from William Tucker, who is “just” a journalist — not unlike some other people who seem to have decided, unilaterally as far as I can tell, that solid zirconium alloy explodes at 2,000 degrees.

Adams, at least in this paragraph, doesn’t claim that science “proves” anything about a real-world nuclear meltdown, for which I am thankful.

What’s important here is to stick to demonstrable, documented facts — not wild extrapolations from the only case we have to consider.

That’s how one creates a cogent argument on a scientific or engineering matter. Shouldn’t that be obvious to any professional journalist?

What is this, rocket science?

Oh, one last thing — It’s nothing, really. Nothing at all! Just a…well, I guess I should mention it.

Adams does appear to be wrong on a central fact, which would be nit-picky of me to point out — maybe even a little rude — if it wasn’t kind of a big one. Here’s a quote from the Nuclear Regulatory Commission’s Backgrounder on the Three Mile Island Incident:

Because adequate cooling was not available, the nuclear fuel overheated to the point at which the zirconium cladding (the long metal tubes which hold the nuclear fuel pellets) ruptured and the fuel pellets began to melt. It was later found that about one-half of the core melted during the early stages of the accident. Although the TMI-2 plant suffered a severe core meltdown, the most dangerous kind of nuclear power accident, it did not produce the worst-case consequences that reactor experts had long feared. In a worst-case accident, the melting of nuclear fuel would lead to a breach of the walls of the containment building and release massive quantities of radiation to the environment. But this did not occur as a result of the three Mile Island accident.

[Link.]

Get it? About one-half the core melted at Three Mile Island, not 20%-30% as Adams has stated. Frankly, I like Adams’s writing. But the explicit misrepresentation of a number so central to his assertion calls everything he says into question.

I’m not a nuclear engineer — I’m a fucking horror writer. I write amusing pieces about zombie attacks at Dartmouth! I drop one-liners about autogiros! I debate e-book rights, not containment vessels! I got a “C” in Chemistry, for the love of God.

So it’s possible there’s some nuclear engineer ba-da-bing Adams could lay on me that would indicate the NRC’s talking out it’s ass. Hey, it wouldn’t be the first time. But, just speculating, I find it more likely that Adams carelessly misremembered the fact. He does appear to have retained the important takeaway — whatever percentage of the core melted at Three Mile Island, the containment vessel remained intact.

If that’s true, or even if it’s not, what else are any of these people being careless about?

Not sure what Adams’ response would be to that one, but I’ve got metal fatigue.

I’m going home to pet my dog and turn the lights off for a while.

Screencap from the entry movie at William Tucker’s site, TerrestrialEnergy.org.

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#5 and #6 Fukushima I Reactors Now Overheating; Fire at #4 Put Out

March 15th, 2011 5 comments

Before and after image of Fukushima I, from Wikipedia.

The latest BBC News story on the Fukushima I site buries the following in the tenth paragraph:

Chief Cabinet Secretary Yukio Edano said they were closely watching the remaining two reactors at the plant, five and six, as they had begun overheating slightly.

[Link.]

Until yesterday morning, it had not been reported in the western press that Fukushima’s reactor #2 was having problems. Reactors #1 and #3 were reported yesterday by the BBC to be “somewhat stabilised,” whatever that means, but #2 was still reported to be out of control. And the claim that #1 and #3 were stable was made before it was reported last night by the New York Times that “all” workers were being withdrawn from the site. “All.” How is it, then, that #1 and #3 are going to stay stable?

The repeated messages of “don’t worry about it” from the Japanese government and Tepco, the company that operates the plant, are sounding tinnier and tinnier with every meltdown.

Regardless, plants #5 and #6 “overheating slightly” really doesn’t mean anything yet. It may never. Wouldn’t that be nice?

With all sarcasm aside, the “real” bad news at Fukushima is coming fast and furious, so none of us need to overreact to the overheating of reactors #5 and #6.

First, the fire at the fourth reactor. This is the one that hasn’t blown up yet. At about 2 a.m. GMT, that fire’s been put out, says the Wall Street Journal at about 4 a.m. Eastern time.Guess what? It’s not being confirmed WTF caused it. The fire was not actually at the #4 reactor but at spent fuel pool at the #4 reactor. This is the storage area for the fuel rods that have completed their operational life but are still “hot” — both literally hot, and radioactive.

At most civilian reactors, the spent fuel rods are stashed onsite to be collected for disposal. Since they are still experiencing significant decay heat, they are hot enough to catch fire if coolant (water) isn’t kept circulating over them. It’s already been established that hot fuel rods with zircaloy (zirconium alloy) cladding give off hydrogen. So the IAEA’s claim reported in the Journal that:

…The Japanese authorities are saying that there is a possibility that the fire was caused by a hydrogen explosion…

Sounds about as ludicrous as the rest of the crap the Japanese authorities confirm the “possibility” of about every five minutes, just before we find out it’s already happened — especially since The Guardian reported that the #2 explosion (the most recent one):

…was followed by a fire that broke out at the No 4 reactor unit, which appeared to be the cause of today’s radiation leaks. That reactor was shut down for maintenance before the earthquake, but its spent fuel rods are stored in a pool at the site. The fire was later extinguished but Kyodo reported that the pool was subsequently boiling, with the water level falling. If the water boils off there is a risk that the fuel could catch fire, sending a plume of radiation directly into the atmosphere.

[Link.]

The fire at the spent fuel pool, by the way, already caused significant radiation release, by the way, which one source was saying the Japanese government claimed was “seven times” what could cause cancer. That makes no real medical sense from what I know, or at least it’s stunningly unspecific. Thankfully, the BBC story has a helpful sidebar as to just how much cancer it can cause.

Shouldn’t acute radiation sickness be the newswriter’s more measurable benchmark, especially since it will directly hamper the disaster control work well before cancer becomes a definable issue? Or is it just that “cancer” is a buzzword to the punters?

Regardless, here’s an observation: It makes sense that the most significant radiation release so far would be from the spent fuel pool fire and not the explosions in #1, #2, and #3, because there are likely a lot more spent fuel rods stored than there would live fuel rods in a single functioning core. (Or, for that matter, one that’s melting down). Previously, radiation levels have been reported to be falling, then rising, then falling, then rising again; they’ve been reported as 1,000 “times normal,” which means almost nothing in practical terms, and “20 times normal,” and now “7 times what can cause cancer.”

Oh, also. You know those sailors who putter around the globe with pounds of plutonium strapped to their asses and say things like “Boo-yah!”? They’re bugging out. U.S. warships off the coast have been withdrawn because of radiation, says The Telegraph:

U.S. warships and planes helping with relief efforts moved away from the coast temporarily because of low-level radiation. The U.S. Seventh Fleet described the move as precautionary.

[Link.]

France is classifying the event as 5 or 6 on the international nuclear event scale (Three Mile Island was a 5, Chernobyl a 7). The Telegraph again:

France’s ASN nuclear safety authority said the accident could be classified as a level 5 or 6 on the international scale of 1 to 7, putting it on a par with the 1979 U.S. Three Mile Island meltdown, higher than the Japanese authorities’ rating.

Japan’s nuclear safety agency has rated the incidents in the No. 1 and No. 3 reactors as a 4, but has not yet rated the No. 2 reactor.

[Link.]

Last I’d heard, the Japanese nuclear safety agency had rated the whole thing a 4. That was before the third explosion, the one at #2. It was when that agency knew #2 was having problems, but it had not been reported. Furthermore, the above paragraph from the Telegraph gives the impression that the events at #1 and #3 are “over” and can reasonably be rated — when, in fact, at least from what I’m reading, their cores may be in the actual process of complete meltdown.

By the way, there appear to be ongoing disaster control efforts, even though the New York Times reported last night that “all” workers had left the plant? Here it is again, in case you missed it:

Industry executives said that in fact the situation had spiraled out of control and that all plant workers needed to leave the plant to avoid excessive exposure to radioactive leaks.

Who knows?

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Containment Vessel Breached; Workers Flee Fukushima I

March 14th, 2011 No comments

The New York Times reports that workers have been withdrawn from the Fukushima I site, indicating that not one, not two, but three complete core meltdowns are very likely.  The withdrawal of workers came following what appears to be a breach of the steel containment structure, which encloses the core, on the #2 reactor. The withdrawal of the workers means all three cores are extremely likely to melt down fully.

At the very end of the New York Times quotes Princeton professor Frank von Hippel: “It’s way past Three Mile Island already. The biggest risk now is that the core really melts down and you have a steam explosion.”

I don’t know who von Hippel is or if he knows what he’s talking about, but the steam explosion he’s talking about sounds like what’s called the China Syndrome (hence the movie of the same name).

That’s when an out-of-control molten mixture of core material, melted cladding, melted machinery, melted control rods, melted steel containment vessel the concrete floor of the containment building (“a substance known as corium”) melts into the earth, hits groundwater, and causes a steam explosion and mushroom cloud. It’s supposed to be physically impossible. Nuke fans have been swearing up and down that such a thing can’t happen. At Chernobyl, a giant “elephant’s foot” of molten corium was found in the basement of the containment building, but it didn’t hit groundwater. (The explosion at Chernobyl was unrelated to the melting; it happened at the beginning of that disaster).

From the NY Times:

…The nuclear fuel in [the #2] reactor was exposed for many hours, increasing the risk of a breach of the container vessel and a more dangerous emissions of radioactive particles….By Tuesday morning, the plant’s operator, Tokyo Electric Power, said it had fixed the valve and resumed seawater injections, but that they had detected possible leaks in the containment vessel that prevented water from fully covering the fuel rods.

That means the containment vessel is leaking water; that means it’s been breached. The official reports hadn’t even acknowledge a problem at #2 until this morning.

More from the NY Times:

…An explosion at the most crippled of three reactors at the Fukushima Daiichi Nuclear Power Station damaged its crucial steel containment structure, emergency workers were withdrawn from the plant, and much larger emissions of radioactive materials appeared immiment…The sharp deterioration came after government officials said the containment structure of the No. 2 reactor, the most seriously damaged of three reactors at the Daichi plant, had suffered damage during an explosion shortly after 6 a.m. on Tuesday.

They initially suggested that the damage was limited and that emergency operations aimed at cooling the nuclear fuel at three stricken reactors with seawater would continue. But industry executives said that in fact the situation had spiraled out of control and that all plant workers needed to leave the plant to avoid excessive exposure to radioactive leaks.

If all workers do in fact leave the plant, the nuclear fuel in all three reactors is likely to melt down, which would lead to wholesale releases of radioactive material — by far the largest accident of its kind since the Chernobyl disaster 25 years ago.

[Link.]

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