A radiation accident earlier this month at the Japan Atomic Energy Agency's facility in Oarai, Ibaraki Prefecture, underlines the need for operators of facilities handling radioactive substances to make sure there are no flaws in their safety systems and procedures. Such caution is all the more important since Japan will have to manage large amounts of radioactive substances in decommissioning nuclear power reactors, including the agency's fast-breeder reactor Monju, which the government decided last December to take out of service.

The accident occurred when five workers were taking stock of 300 grams of uranium oxide and plutonium oxide put in a cylindrical stainless steel container at the Plutonium Fuel Research Facility in the agency's Oarai Research and Development Center. The powdery substances had been encased in a double-wrapped plastic bag placed inside the container, whose lid was fastened with six bolts. When one of the workers opened the lid, the black powder sprayed out under pressure, exposing the men to radiation. The fiver workers were admitted to the National Institute of Radiological Sciences's hospital in Chiba for treatment.

The fiasco brings to mind the 1999 criticality accident at a nuclear fuel processing facility operated by JCO Co. in Tokai, Ibaraki Prefecture, which killed two workers — the worst nuclear radiation accident in Japan prior to the 2011 meltdowns at the Fukushima No. 1 power plant. The fatal accident occurred when three workers were preparing a small batch of nuclear fuel using uranium enriched to 18.8 percent. They were handling the nuclear fuel in stainless steel buckets. The company apparently failed to give workers proper safety training, and sloppiness was the clear cause of the accident.