Atomic agency backs safety tests for Japan’s reactors

A United Nations fact-finding mission on Tuesday tentatively supported new stress tests devised to determine whether Japan’s nuclear plants can withstand another emergency, throwing its weight behind a government push to restart reactors idled in the wake of the disaster at the Fukushima Daiichi plant after an earthquake and tsunami in March. Experts from the International Atomic Energy Agency, which reports to the United Nations and is based in Vienna, were in Japan at the request of the government to review stress tests ordered by the country’s nuclear regulator on reactors across the nation. The government is eager to dispel public mistrust of nuclear power and restart the reactors, which until recently provided 30 percent of Japan’s electricity needs. But because of heightened local opposition to nuclear power after the meltdowns at the Fukushima Daiichi Nuclear Power Station nearly a year ago, communities across Japan that host reactors have blocked them from restarting after mandatory shutdowns required every year for maintenance. Only 3 of the country’s 54 nuclear reactors are operating, and the rest are likely to be halted in the coming months, raising fears of a power shortage during peak summer months. In a bid to quell those fears, Japan’s nuclear regulator, the Nuclear and Industrial Safety Agency, has ordered the country’s nuclear operators to conduct stress tests, or computer simulations that analyze whether a reactor can withstand disasters like earthquakes and tsunamis. In January, the agency said it had reviewed stress tests conducted on two reactors at the Ohi Nuclear Power Plant, in central Japan, and concluded that the plant would survive a disaster similar to the magnitude 9.0 earthquake that jolted eastern Japan in March and set off a tsunami. More than 22,000 people have been listed as dead or missing in connection with the earthquake and tsunami. In its preliminary assessment released on Tuesday, the I.A.E.A. said those checks met the agency’s safety standards. Japanese regulators’ checks of emergency measures at the plant were “appropriate and enhanced confidence” in the reactors’ resilience to disasters, the agency said in a statement. It also issued a list of recommendations for earthquake-prone Japan, including a more detailed analysis of the risks caused by earthquakes and tsunamis. “What we saw was a process that we felt comfortable with. But in any process, there is always room for improvement,” said James Lyons, leader of the eight-person team. The preliminary report yielded few details of the contingency measures the atomic agency had deemed sufficient. Japan’s nuclear operators have promised higher sea walls at their plants to protect against tsunamis, as well as better ways to prevent power station blackouts, which can shut off vital cooling systems and cause the reactors’ cores to overheat. The I.A.E.A.’s spokesman, Greg Webb, also emphasized that the agency was not vouching for the absolute safety of nuclear power plants in Japan, or whether they were a good fit for the nation. “We could never do that,” Mr. Webb said. “You can never be complacent about nuclear safety.” It was up to Japan to weigh the risks and benefits of nuclear power to determine whether it should form part of the nation’s energy supply, he said. Even if it restarts its idled reactors, Japan has said it will eventually phase out nuclear power. That could take a long time: recently proposed legislation, if enacted, could allow some reactors to operate for as long as 60 years. The atomic agency is scheduled to submit a final report on its findings to the Japanese government by the end of February.