Prof. Hiroaki Koide of Kyoto University: ‘No One Knows How Fukushima Could Be Wound Down’ – Corium May Be Melting Through the Foundation

Related info:

Was Fukushima a China Syndrome? (TIME):

The China Syndrome refers to a scenario in which a molten nuclear reactor core could could fission its way through its containment vessel, melt through the basement of the power plant and down into the earth. While a molten reactor core wouldn’t burn “all the way through to China” it could enter the soil and water table and cause huge contamination in the crops and drinking water around the power plant. It’s a nightmare scenario,the stuff of movies. And it might just have happened at Fukushima.


- Hiroaki Koide of Kyoto University: “No One Knows How Fukushima Could Be Wound Down” As the Corium May Be Melting Through the Foundation:

So says Hiroaki Koide of Kyoto University Research Reactor Institute, in a telephone interview on May 19 with independent video-journalist Tetsuo Jinbo of Videonews.com (who did the video report of the 20-kilometer radius evacuation zone back in April, showing cows and dogs prowling the deserted towns).

Koide is practically agreeing with Christopher Busby that there’s not much anyone can do to stop the release of radioactive materials and further contamination of air, soil and water, other than somehow “entomb” the reactors (a.k.a. Chernobyl solution).

Koide reiterates his view that the corium (he says “melted fuel” and “melted core” in the interview for lay people, but it is melted fuel, and anything else that melted with the fuel inside the RPV) may have already escaped the Containment Vessel in the Reactor 1.

Following is my notes as I jotted down the salient points Koide made in the interview:

  • (Assuming that TEPCO is telling the truth) the worst-case scenario of a hydrogen explosion inside the reactor caused by the melted fuel seems to have been avoided.
  • I believe the Reactor Pressure Vessel has a large hole, not the small holes that TEPCO says.
  • TEPCO cites the pressure and the temperature data as the reasons to believe the melted fuel still stays inside the RPV. However, I wonder if the pressure and the temperature data of the Reactor 1 is accurate. After all, the data on the water level was completely wrong.
  • That much water has leaked (4,000 tons in the reactor building basement) and yet TEPCO says there’s still pressure inside the RPV. It is impossible, given the structure of the reactor.
  • There is no definite data as to whether there is any water in the Containment Vessel. Considering the reactor building basement is flooded with water, I think it is possible that the melted fuel already damaged the Containment Vessel.
  • Outside the Containment Vessel, what’s left as containment is the concrete foundation of the building.
  • In order to have a reactor in cold shutdown, you need to have the RPV intact so that the cooling water can circulate. No point in talking about cold shutdown when we don’t even know whether the fuel is still inside the reactor.
  • We’re in the uncharted territory that we enter for the first time ever since the human race started to use nuclear power.
  • As to whether the radioactive materials are going to be released into the atmosphere [from the meltdown and breach of RPV and Containment Vessel], I don’t think it is likely as of now. The concrete foundation of the reactor building may have sustained some damage, but as a whole I don’t think it is completely broken.
  • I cannot properly assess the possibility of the corium melting through the concrete foundation and reaching the water table. If that should happen, the radioactive materials will flow into the ground water and contaminate the ocean even more.
  • As to the the corium, I think the inside of the corium is not solid even if there’s water in the reactor.
  • The Suppression Chamber in the reactor building basement is torus-shaped. The location where the corium may have dropped is the center of the torus, and it is concrete. The thing to worry about is how far down the concrete the corium will go.
  • The water circulation system using water in the building proposed by TEPCO is tantamount to admitting that the Containment Vessel is broken. It is a much more serious situation than I envisioned, and there’s no other way to cool [the corium] other than the one proposed by TEPCO.[Koide was proposing a system that circulate water inside the Containment Vessel back into the RPV, as he had assumed correctly that the RPV had been breached.]
  • However, if the corium goes into the concrete, no point in talking about circulating water to cool. There will be nothing you can do. The only way may be to entomb the whole building in a concrete coffin.
  • I suspect that TEPCO’s “roadmap” was created by the TEPCO headquarters under political pressure, and not by the TEPCO people in Fukushima I Nuke Plant who struggle everyday to contain the situation. If anything, the “roadmap” should be created by them, not by the headquarters.
  • According to TEPCO’s data, even now the fuel rods in the Reactors 2 and 3 are soaked in water up to half the height.
  • Comparing Chernobyl and Fukushima, Fukushima is still on-going. There is a possibility of further hydrogen explosion, and it is still possible that Fukushima exceeds Chernobyl in terms of magnitude of the disaster.


For those of you who understand Japanese, here’s the interview:

If you are curious about this maverick nuclear researcher, here’s a good interview of him done in 2007 (translated from original Japanese). Koide entered the field of nuclear science full of hope for the peaceful use of nuclear technology in 1968, only to see the reality two years later when he saw Onagawa Nuke Plant being forced upon the residents and understood why. Ever since, he has continued to research nuclear energy as an opponent of nuclear energy.

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