Possible Worst Case Scenario At Fukushima: A ‘MELT OUT’ (Even Worse Than A MELT TROUGH!)

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メルトアウト「核燃料」地下水直撃の恐怖! メルトスルーを超える最悪の事態. 東電はこの可能性を隠していないか! (Gendai, July 8, 2011):

Google translation:

Melt-out “nuclear fuel” struck fear in the groundwater? Beyond the melt through the worst. TEPCO do not hide this possibility!

“Cooling system” circular if it is not only deprived eye! Molten fuel what’s going on now. In the basement of the reactor building, “a frightening reality possible” experts knew

TEPCO, the Fukushima Daiichi “cooling system circulation,” Note that is bent on running.

Prevention Office at the beginning of the meeting of June 27, consolidated government TEPCO, assistant to the prime minister Hosono Zhi Hao (the current minister in charge of nuclear accidents) is “closer to the goal of stabilizing the cooling. A big step,” said 6 cooling system had been dead 18, was resumed in the chest filled with 20:04 minutes yesterday evening. Towards the end of the meeting, but with downcast eyes, Junichi Matsumoto, Acting Chief of the TEPCO nuclear location, “may know” to report a damper on the mood and optimism.

“There is leakage from the seam of the hose, the water injection was stopped at 5:00 pm on 55 minutes’

From resume, just 90 minutes. TEPCO that “measures of resuscitation” cooling system is expected, he had been frustrated once again. The cooling system on June 28 began to run again the following year or longer would be stable in time.

“In the rush job because the system produced, will be repeated unexpected trouble in the future. Is particularly concerned about aftershocks. Cooling system, the piping extends over the entire circumference of about 4km. Therein, the melting of nuclear fuel is the mass flow of polluted water containing high concentrations of thing. if such loose screws or damage the pipe connecting portion at a major aftershock if will be widely scattered radioactive material “(Technology Critic Home Atsushi Sakurai)

As pointed out by Mr. Sakurai, until stabilization of unpredictable cooling system failure will occur in the future. But the situation is even worse. Unimaginable “terrible reality”, but might be going on deep inside the reactor building basement —.

International Atomic Energy Agency released on July 6 (IAEA) report to the government in Unit 1 to 3 “through” molten acknowledged that possibility. This is the core melt (melt down), the nuclear fuel, penetrate the reactor pressure vessel, they pouring outside containment to further “melt-through” but that the state (see right).

But “at the Fukushima Daiichi more desperate situation,” you said, is Assistant Professor Hiroaki Koide of Kyoto University Reactor.

“The melt-lump of uranium is the fuel melted, defeating even the bottom of the containment, and I believe that it is not at that Meri込N on the ground melted the concrete beneath the reactor building. Part of the core of nuclear fuel soluble exceed the 2800 ℃ (can not be measured because the current temperature of the high radiation dose.) weight of the melt is also 100t. steel pressure vessel and containment would melt at about 1500 ℃ from the melt should have fallen on the floor of the reactor building basement. some of which eroded the floor of the basement, some would have melted the contaminated water to flow to the surrounding walls “

It leaks out directly to the outside of the reactor building of nuclear fuel, radioactive materials spread around very high levels of “melt out” It’s called the worst condition. Mr. Koide continue.

“If you hit the groundwater melt, then spread of radioactive material be cooled circulating some will not prevent you can not. As long as stopping the flow of groundwater, the sea around is to continue being contaminated. To prevent pollution Gutameniha, Shikanai would make the sides of the shield wall of the reactor building basement. The contaminated soil and the melt is cut off contact with groundwater, “

Also look to the structure of a nuclear reactor melt-out potential is happening is high. The explanation is that, it was a design engineer who Masashi Goto containment vessel Toshiba original.

“The thickness of the steel pressure vessel also has a few cm enough. The thickness of the containment, while only 20 ~ 30mm. Pressure vessel also is has been designed to withstand the pressure 70 stores The pressure vessel is set 4. you get enough fuel to leak if the pressure vessel melt, containment not stand a chance. including the reactor building basement concrete wall covered let alone a mere super-hot melt is not to avoid.

Containment pressure vessel can be the first place, not being done on the assumption that the core melt. Design has already been compromised. Any action be taken to melt down, so penetrate the containment vessel pressure from the melt of the floor would melt out of the reactor building basement is a matter of time “

Radioactive material scattered by melt-out, and something more deadly. Some of the contaminated water which overflowed from the underground to the surface, such as iodine and cesium in two years in 08 half-life of radioactive material containing a lot of light at the top of the water reservoir and easy. The leaking from underground, however, it becomes radioactive material such as plutonium, strontium and 40,000,002 for the year of the half-life of 29 years. Plutonium, in particular, continues to destroy the internal organs into humans over 50 years, “radioactive material” worst called. Institute of Applied professor at Chubu University, said Mr. Kunihiko Takeda yuan Cabinet Chair Atomic Energy Commission.

“Gushing from underground is a radioactive heavy comparatively easy to settle to the bottom of the water, such as plutonium. If they penetrate the underground nuclear fuel, river and sea substances are highly toxic super these ponds, lakes and wells will end up wherever flow is leaning into the underground water vein. However, the underground man is too high because the radiation dose away, exactly the situation would not everyone can understand “
“Stable” Nevertheless shield wall construction

TEPCO, what are considered to be in the current situation and how the molten nuclear fuel. TEPCO has acknowledged that the meltdown, the answer was not persuasive.

“Analysis is now evaluated as a fall in the bottom of the pressure vessel to melt the fuel No. 1. Has now been cooled to a stable priming situation leads to the release of radioactive material for large future happen I think not. No. 2, No. 3 well, moving forward with a similar analysis. For specific conditions in the reactor is not known. in that hole in the containment has pointed out that for Also, we will report on current research while promoting “(Public Relations Department)

In short, nuclear fuel is “being cool” stable but every claim to melt through, the possibility of melt-out, not knowing any more details “under investigation,” he say. TEPCO Moreover, while answering it, is considering the construction of the shield wall extending deep underground beneath the reactor building.

“We have started to design. To shield the contaminated groundwater, and we are planning to build” (ibid).

As mentioned earlier, Koide said, “to prevent the outflow of the groundwater hit the nuclear fuel only to make a shield wall” has been warned. Mentioned in his mouth trying for the worst might be happening but are not aware of the possibility of TEPCO will melt out in motion measures that have begun or not. Fukushima Daiichi nuclear power plant works in reveals that one of the employees of subcontractors.

“Since the beginning of June, I suspect the movement of the TEPCO. Until then, J Village (outpost of Naraha nuclear accident in the town, Fukushima Prefecture), and stretched out on board the status of each daily reactor building was. More recently, however, there are no such reports. 元請Ke (parent company) also listen to the director of “from TEPCO reactor building is simply noted as such into the absolute dangerous, mouth suddenly become heavier, “and is pointless. Our workers’ de pace that TEPCO what you up to in a nuclear reactor” and I have therefore questioning ”

Fukushima Daiichi nuclear power plant in the basement of a human can not enter, progress may have never encountered the horrors of mankind.

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