Government withheld 1984 report of a simulated attack on a nuclear power plant — The Japan Times

” The Foreign Ministry secretly conducted a simulation in 1984 to assess damage from a hypothetical attack on a nuclear power plant in a war and concluded that up to 18,000 people would be killed with acute symptoms from radiation exposure, it emerged Wednesday.

The previously secret report also mentioned the possibility of a hydrogen explosion that could follow the meltdown of fuel rods in a nuclear power plant, the exact phenomenon that happened during the 2011 Fukushima crisis.

Anti-nuclear activists slammed the ministry for not publicizing the report earlier, allegedly out of fear that the warnings could fan anti-nuclear sentiment among the public.

“The report should have not been held secret. (The government) should publicize it and consider how it can protect” nuclear power plants, said Hideyuki Ban of the Citizens’ Nuclear Information Center.

The content of the document was first reported Wednesday by the Tokyo Shimbun, which obtained a copy of the 63-page report through the information disclosure law.

The Japan Times confirmed the outline and key conclusions of the report with a senior Foreign Ministry official.

According to Yasushi Noguchi, head of the ministry’s arms control and disarmament division, the ministry asked the Japan Institute of International Affairs, an affiliate of the ministry, to draw up the report after Israel staged an airstrike and destroyed a reactor under construction in Iraq in 1981.

Noguchi said the report concluded that up to 18,000 people would die in the worst-case scenario if the primary containment vessel of a 1 million kilowatt-class reactor in Japan was severely damaged and local residents did not evacuate immediately.

In another scenario, the report also warned that if all power supplies were cut and critical cooling functions lost, fuel rods would melt down. The hydrogen generated from metals used for fuel assembly cladding could then potentially cause an explosion.

This type of hydrogen explosion actually happened and aggravated the meltdown crisis at the Fukushima No. 1 power plant after the massive tsunami of March 11, 2011, knocked out the power supply, killing the critical cooling operation.

Few plant workers and nuclear experts anticipated a hydrogen explosion until one actually ripped through the No. 3 reactor building.

The Tokyo Shimbun alleged the Foreign Ministry did not publish the report because it feared it would fan anti-nuclear sentiment while the government was trying to build more nuclear power plants in the 1980s.

Noguchi said it was not published because it was intended as an internal reference for Foreign Ministry officials.

Ban claimed nuclear plants in Japan are not designed to be robust enough to withstand missile attacks or a suicide airplane crash such as the 9/11 terrorist attacks in New York in 2001.

The Nuclear Regulation Authority now requires that reactor buildings be robust enough to withstand the “intentional crash of a large aircraft” and other terrorist attacks.

But the NRA declines to disclose any more details of the safety regulations, saying they should be kept secret for security reasons. ”


Three methods proposed for removing melted fuel from Fukushima No. 1 reactors — The Japan Times; The Yomiuri Shimbun

” FUKUSHIMA – The Nuclear Damage Compensation and Decommissioning Facilitation Corp. on Thursday proposed three methods for retrieving highly radioactive nuclear fuel debris in three crippled reactors at Tokyo Electric Power Co.’s disaster-stricken Fukushima No. 1 nuclear power plant.

The proposals, presented at a meeting of officials from Tepco, the central government and municipalities in Fukushima Prefecture, will be reflected in a decommissioning road map that the government and Tepco are set to release around May.

The three reactors underwent core meltdowns in March 2011, leaving melted nuclear fuel debris on the floor of their containment vessels. The decommissioning aid body hopes to establish concrete procedures by the first half of fiscal 2018.

One of the three proposed methods removes the debris in a submerged condition, with a containment vessel filled with water to shield against radiation and prevent the spread of radioactive materials during the retrieval process.

An alternative dry method carries out the retrieval in a partially submerged condition, with water used only when the debris is cut loose from the vessel floor. The debris would be removed from either the top, under one plan, or the side of the vessel, under another.

The submersion method requires the reactor damage to be accurately identified and repaired before water is poured in. The dry method, on the other hand, requires continuous cooling of the retrieved debris and measures to prevent radioactive materials from scattering.

Radiation levels at the three reactors are so high that workers have been unable to approach their containment vessels or identify the location of the debris. All the three methods call for an assessment beforehand of radiation contamination as well as decontamination procedures.

Tepco plans to begin inspections of reactor 1 Friday using robots mounted with cameras and radiation-measuring equipment. ”


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Read a related article by The Yomiuri Shimbun