Japan underestimated the risk of tsunamis and needs to closely monitor public and workers' health after the crisis at the Fukushima Daiichi nuclear plant, a team of international safety inspectors said in a preliminary review of the nuclear disaster.
The report, from an International Atomic Energy Agency (Iaea) team led by Britain's top nuclear safety official Mike Weightman, highlighted some of the well-documented weaknesses that contributed to the crisis at Fukushima when the plant was hit by a massive earthquake and then a tsunami in quick succession on March 11th.
Those start with a failure to plan for a tsunami that would overrun the 5.7-metre breakwall at Fukushima and knock out back-up electric generators to four reactors, despite multiple forecasts from a government agency and operator Tokyo Electric Power Co's own scientists that such a risk was looming.
The Iaea team said Japan's crisis offered several lessons for the nuclear industry globally, including that plant operators should regularly review the risks of natural disasters and that "hardened" emergency response centres should be established to deal with accidents.
"The tsunami hazard for several sites was underestimated," the report's three-page summary said. "Nuclear plant designers and operators should appropriately evaluate and provide protection against the risks of all natural hazards."
Goshi Hosono, an aide to prime minister Naoto Kan, accepted the report, marking the first step in an effort by Japanese officials to show that the lessons learned from Fukushima can be applied to make its remaining reactors safe.
Mr Hosono said the government would need to review its nuclear regulatory framework.
The Iaea team will submit its findings to a ministerial conference on nuclear safety in Vienna from June 20-24th.
"We had a playbook, but it didn't work," said Tatsujiro Suzuki, a nuclear expert and vice chairman of Japan's Atomic Energy Commission.
The economic stakes are high. Japan is operating only 19 of its pre-Fukushima tally of 54 reactors.
In the worst case, all of Japan's reactors could be shut down by the middle of 2012. That would take out 30 percent of the nation's electricity generation and raise the risk of deeper, near permanent power rationing, officials say.
The Fukushima accident has forced more than 80,000 residents from their homes and raised deepening concerns about the safety of nearby children, workers battling to stabilise the reactors and the food supply as radiated water leaks from the site.
In the report, the IAEA team urged Japan to follow up with monitoring of worker and public health.
The report said it was also dangerously unclear who was in charge on the ground at Fukushima. Tepco's chairman was in China, the utility's president was grounded in western Japan on a personal trip. Sakae Muto, the ranking Tepco official, spent the night of the quake huddled with mayors of small towns near Fukushima, giving them formal notice of the incident rather than joining the command centre.
The plant's chief operating officer, Masao Yoshida, ignored an order to stop injecting seawater into the No 1 reactor based on a request from Mr Kan's office. Experts say Mr Yoshida made the right call, but say the confusion underscored the bigger problems in the early response to the accident.
Reuters