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Nuclear Risk Expert: Fukushima Fuel May Be Leaking
An anonymous reader writes "Three weeks after the nuclear crisis began at Japan's Fukushima Dai-1 power plant, there's still a real danger of melted nuclear fuel escaping the reactor buildings and releasing a large dose of radiation. So says Theo Theofanous, an engineer who spent 15 years studying the risks of nuclear reactors. Theofanous believes that melted nuclear fuel has already leaked through the reactor vessels and accumulated at the bottoms of the primary containment structures. All attempts to keep the reactor buildings cool may not be enough to prevent the overheated fuel from eating through the concrete floors, he says."
Another hopeless optimist. Japan is a high-tech country. Japan is not hampered by an anti-nuclear movement. Japan builds new reactors. Japan's reactors are highly regulated for safety. None of that has prevented them from having aging reactors, operated by a corrupt company. If this can happen in Japan, it can happen anywhere.
Now it's not just a matter of "sealing it and shutting it down": If the core melts through the floor, how are you going to seal that up? The crux with nuclear power is that even undamaged reactors are high maintenance for decades after they've been shut down at the very least. So far nobody has figured out what to do with the "spent" fuel and other radioactive waste. Attempts to bury it have repeatedly resulted in unforeseen accidents with the result that even more radioactive waste needs to be dug up and stored above ground, essentially forever. This stuff isn't just radioactive, it's also extremely toxic and chemically aggressive.
No nuclear facility is insured to an amount that would cover all damages which an accident could cause: No insurer is willing to take the risk. The risk is entirely on the shoulders of the public, who cannot reject it, thanks to representative democracy and bought politicians. The exception to the rule is Austria: In a fluke of common sense, they held a referendum before Austria's first nuclear power plant (completed and ready) was going to be activated: The Austrian people rejected nuclear power and they have not reneged so far.
Oh pooh. Any electrician working at an industrial facility knows exactly how to fix this and with an emergency of this nature the parts would come in via very special delivery very very quickly.
The problems were a LOT more serious - switchgear wiped out, pumps destroyed, no water supply, no instrumentation working, and a lot more.
The IAEA is reporting that measured soil concentrations of Cs-137 as far away as Iitate Village, 40 kilometers northwest of Fukushima-Dai-Ichi, correspond to deposition levels of up to 3.7 megabecquerels per square meter (MBq/sq. m).
Compare this with the deposition level that triggered compulsory relocation in the aftermath of the Chernobyl accident: the level set in 1990 by the Soviet Union was 1.48 MBq/sq. m.
From http://www.japan.org
The authorities don't know how the water is leaking out and don't know the upper bound on the total amount of radioactivity released. The lower bound is already rather staggering. In addition, radioactive materials have already leaked into the ocean and the ground water. TEPCO said the level they measured in the ground water was the similar to the high levels found in the turbine buildings and the tunnels outside the plants. The Japanese Nuclear and Industrial Safety Agency said those readings were way too high so they asked TEPCO to measure again more carefully.
The only specific theory I've heard of how the thousands of tons of highly radioactive water got out of the containment vessel is that it got out via graphite seals in the bottom of the vessel. There are holes there for control rods and the holes are blocked with graphite seals. The seals will fail at high temperatures and melted fuel rods falling to the bottom of the vessel would provide more than enough heat to cause the seals to fail. If it is any solace, reactors that don't contain melted fuel rods probably don't have leaks all over the bottom of the containment vessel.
The radioactivity released at Chernobyl escaped upward into the air. This made it easier to get a handle on the magnitude of the total amount of radioactivity released. The release at the light water reactors at Fukushima is for the most part traveling downward, to basements, tunnels, ground water, and the ocean. This makes it extremely difficult to get a handle on the total amount of radioactivity that has been released. They really don't know of the bulk of it is in the thousands of tons they have already discovered or if that is just the tip of the iceberg.
We don't see the world as it is, we see it as we are.
-- Anais Nin
That's not how a reactor works.. Sure, you "shut it down" by inserting the control rods, but it's not an off switch. It needs days to cool down, all the while still able to heat water and spin turbines.
I don't know what was providing systems power and how that was lost.
mod me funny