MITO, Ibaraki Pref. – The trial over Japan’s worst nuclear accident opened Monday with six JCO Co. employees pleading guilty to charges of negligence resulting in death and the company pleading guilty to violating the Nuclear Reactor Regulation Law.
The trial over the 1999 criticality accident at a JCO facility in Tokai, Ibaraki Prefecture, that killed two JCO workers is being held before the Mito District Court.
Kenzo Koshijima, 54, former head of the uranium processing plant in Tokai, and five other employees pleaded guilty to negligence.
JCO President Tomoyuki Inami entered a guilty plea on behalf of the company, saying, “I know it’s too late for regret. I can only pray for the souls of the dead.”
The six employees are charged with allowing other workers to skip lengthy procedures and instead use buckets to manually mix a uranium solution, leading to the Sept. 30, 1999, accident at the plant.
The five other employees who pleaded guilty are Hiromasa Kato, 61, chief of production at the time; Hiroyuki Ogawa, 43, leader of the planning group when the accident occurred; and three senior workers — Hiroshi Watanabe, 49, Kenji Takemura, 32, and Yutaka Yokokawa, 56.
Koshijima and other officials allegedly approved the illegal procedures at an in-house safety committee in 1995, leading to the compilation of an unauthorized manual in 1996 that recommended buckets be used to make the solution.
According to the indictment, the accident and subsequent nuclear fission chain reaction occurred when three workers poured too much of the solution into a processing tank that already contained another component, bypassing several required procedures.
Two of the three workers have since died from radiation sickness — Hisashi Ouchi, 35, in December 1999, and Masato Shinohara, 40, last April. Yokokawa was also initially hospitalized but was later released.
Koshijima, Kato, Ogawa and JCO are also charged with violating the Nuclear Reactor Regulation Law by compiling the manual without informing the government.
Operators of nuclear facilities are required by law to obtain the prime minister’s approval before changing their production methods.
Koshijima and JCO are also charged with failing to instruct plant employees on matters of safety.
JCO started using illegal methods to process uranium at the plant in 1993, prosecutors said.
They said at the hearing that JCO had conducted an in-house survey in 1987 and ordered the plant to devise means of hiding illegal equipment and production methods in the event of inspections by the then Science and Technology Agency.
The prosecutors also said the crisis-management committee at JCO’s Tokai office in 1992 had compiled secret documents in which the risk of a criticality accident at the plant was noted.
As a result of the accident, some 600 people — including more than 200 Tokai residents — were exposed to radiation, mostly in minor doses. The six workers were arrested in October.
JCO, a nuclear-fuel processor, is a subsidiary of Sumitomo Metal Mining Co.
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