March 16, 2011

Nuke nomenclature

As the MSM commentariat has become stupider and stupider, it becomes increasingly difficult to tell just what the hell is going on in Fukushima, or, alternatively, just what the Fukushima is going on in Hell.

Terms seem to get used interchangeably. "Containment vessel," "reactor building," "containment structure," et cetera. At the bottom of all this ambiguity is the simple reality that the reporters don't really understand what they're talking about. This has become a major problem in recent years as one tries to follow a big story like the nuclear disaster in Japan.

I do not profess to be any kind of expert on Japanese nuclear plant design, but just looking at the pictures and diagrams, it doesn't really seem all that complicated. Working from the inside out, you have the reactor pressure vessel, which is built along the lines of a tank car in a railroad train. It is made out of very thick steel. Inside the reactor vessel you have the nuclear fuel rod arrays which are immersed in water (to slow the neutron exchange and to cool the fissile process).

At the next level, you have the secondary concrete shield wall. This is an added level of safety which was not present, for example, at Chernobyl. This is a steel-reinforced concrete structure surrounding the reactor vessel.

Lastly, you have the reactor building, which is another, larger box (a building) surrounding the other two structures. It's also made out of concrete. One might think of the whole thing as Satan's Russian Doll.

The fuel storage pool is apparently inside the reactor building and above the containment structure, sort of like a shelf or drawer built below the reactor building roof. These are approximate cubes about 40 feet on a side, filled with bluish, boronated water.

Somehow or other, there have been a number of violent explosions at Fukushima reactors Nos. 1,2 & 4, and in one case at least it apparently blew the roof off the reactor building (No. 2) and in No. 4 blew two 8-meter holes in the side of the reactor building. Here is what (among many things) is troubling about the explosion in Reactor #4: it apparently originated in the spent fuel pool. Trying to reason through this logically, how does an explosion blow holes in the side of the reactor building (see diagram above) without blowing holes in the side of the spent fuel pool?

I suppose it's technically possible, but the confused reporting about what's going on never attempts to explain this clearly. This would appear to be the most severe threat posed to Japan, since the spent fuel rods (or nuclear waste) are huge repositories of all kinds of radioactive stuff. If, as the nuclear site reports, there is extensive damage to nuclear cores within several reactor pressure vessels, but the vessels themselves are still intact (as appears to be the case), then the most logical explanation for the very high levels of radiation being recorded onsite would seem attributable not to the occasional steam releases intentionally performed by the staff but to exposed (uncovered by water) spent fuel rods in one or more storage pools fizzing away their radioactive cesium, iodine, strontium, plutonium and other diabolical stuff. Quite understandably, it's hard for the onsite staff to observe what's going on directly because they don't want to go near the thing.

I don't know, and I know the New York Times will never be able to tell me in comprehensible terms. But I suspect that what's really going on is that there is at least one spent fuel pool with holes in the wall, to put the matter simply, and that the coolant water is leaking through those walls faster than it can be replaced (since the Japanese have no good options for replacing it rapidly). And that the spent fuel rods, as a result, are exposed to air, the zirconium cladding is oxidizing away, and a witch's brew of toxic crap is spewing into the atmosphere.

Only a hunch. Nuclear power plants. As one guy said way back in 1980, it's a lot like using a pile driver to crack walnuts, this business of employing a nuclear chain reaction to boil water. Absolutely fraught with risk, at every stage of production.

March 15, 2011

We're havin' a meltdown

I've been so remiss with the blog that even Dmitry Orlov is posting more than I do, and he swore off frequent posting over a year ago (he didn't stick with it because this process is somewhat addictive). There's a lot going on, as usual, but I haven't been able to develop any particular "take" on it that inspires me to blog, or even bloog. Anyway, the good Dmitry offered this up today:

You see, you have to be a certain sort of person to say “Sure, using a precariously controlled subcritical nuclear pile to boil water to run steam turbines to generate electricity is a great idea!”

That's about where I come out on the subject, although my thinking is not quite the categorical, straight-line approach which Mr. Orlov characteristically takes. I fold the whole analysis into an overall, despondent realization that humanity is probably not going to do much else about global warming in a systematic, timely way, and at least nuclear power has the advantage of being relatively carbon-neutral. Dmitry's view is clearer, I think, because he lives on a sailboat in Boston Harbor, uses solar power (wind) for transportation and solar power (photovoltaics) for electricity. Like the other guy who lived in Massachusetts, whom I honor with the title of this blog, this integrity allows him to state simple truths without compromise. Because, of course, the real answer isn't to find ways of producing more power than we need, but to learn to live with a great deal less of it. It is always the exigencies of advanced technology, and "comfort," that compel us to take these awful risks.

I think I mentioned a couple of times that I was involved, as a lawyer, in the licensing hearings for PG&E's Diablo Canyon nuclear reactors. Those are also boiling water reactors built near an earthquake fault line. As with the reactors at Fukushima, these reactors will be safe until they're not. Part of the drill in participating in licensing hearings is to come up with "scenarios," based on the types of threats (terrorism, weather, natural disaster, war) that a civilian reactor is likely to encounter. If anyone had suggested that Diablo Canyon should prepare for a 9.0 earthquake, followed by a tsunami, followed by electrical failure, followed by human error, followed by desperation attempts to cool reactor cores and spent fuel ponds with seawater, they would have been laughed from the room. C'mon, they would have said, don't you also want to throw in Al-Qaeda while you're at it?

Isn't it amazing. Confirmatory of my "favorite" (and most sinister) of Murphy's Laws: Nature always sides with the hidden flaw. The Fukushima reactors were built near a massive subduction fault line, of precisely the kind that produces huge tsunami waves ("tsunami" being a Japanese word for "harbor wave"). Japan has recorded over 195 tsunamis in its shaky history. You can't really say that what just happened was not foreseeable. It clearly was. The quake was bigger than Tokyo Electric planned for, but the quake did not do the direct damage. The tsunami did. The rest of the sequence was predictable too: electrical failure (grids do not operate as well underwater), pump failure, hydrogen build-up, explosions, panicky responses by humans trying to do too many things in an extremely limited time frame.

So we could see it all coming. We just assumed it wouldn't happen because all these complications get in the way of what we want to do so we can be "comfortable." Similar ideas led to the brilliant solution of placing the spent fuel ponds at Fukushima (I don't know what "shima" means, but if it means "you" it's all becoming clear) on top of the containment buildings. A kind of satanic twofer: if the (unvented) hydrogen from melting fuel rods in the reactor (unventable because of General Electric's design: I thought they brought "good things to life") causes the roof to blow off (as happened there), then you can blow up the fuel pond too, which has a lot more deadly radiation than in the reactor core. Indeed, the Japanese were using MOX fuel, which contains plutonium, so that is also present in the spent fuel rods on top of the (exploding) containment buildings.

Nothing to worry about, because it plainly couldn't happen although it did. So back to Diablo Canyon. Those bad boys are pictured up above, hovering there on a cliff above the Pacific. Safely above sea level. Uh-oh, wait a minute. Wasn't there something about sea level rise predicted by global warming? They won't even need a tsunami down in San Luis Obispo to inundate the plant, although (in mitigation) nature will take care of the solution of flooding the reactors with seawater. Thus, if we continue to melt Antarctica and Greenland (which between them contain 90% of the Earth's fresh water) and we achieve that 200+ foot sea level rise, we'll see how they do.

Or, we can just continue assuming that nothing bad can happen.