Japan’s nuclear regulators need more powers to prevent a repeat of the Fukushima disaster, which was triggered by insufficient defenses against the March earthquake and tsunami, the International Atomic Energy Agency said.
“Nuclear regulatory systems should address extreme external events adequately, including their periodic review, and should ensure that regulatory independence and clarity of roles are preserved in all circumstances in line with IAEA safety standards,” the UN agency said today in a report on the Fukushima Dai-Ichi plant disaster.
The government-run Nuclear and Industrial Safety Agency has been criticized for not ensuring Tokyo Electric Power Co., the plant’s operator, heeded warnings that a tsunami could overwhelm its defenses. A reorganization of Japan’s atomic regulators is “unavoidable,” Goshi Hosono, a special adviser to Prime Minister Naoto Kan, said after the IAEA released its report.
“There’s concern that things have become a little bit cozy and complacent,” Stephen Lincoln, a professor at the University of Adelaide and a specialist in nuclear power, said by telephone today. “It seems in Japan they relied very much on commercial operators to oversee the safety aspects, and if you are running a commercial operation you’ve got to make a profit.”
Tokyo Electric’s plant north of the Japanese capital has been spewing radiation since the March 11 earthquake and tsunami knocked out power and backup generators, crippling cooling systems that led to three of six reactors melting down.
Failure of cooling systems for reactors and water pools storing spent fuel rods led to explosions and fires at the Fukushima plant, causing radiation leaks that forced the evacuation of more than 50,000 households and contaminated drinking water and food. Japan’s government in April raised the severity rating of the Fukushima crisis to 7, the highest on an international scale and the same as the Chernobyl disaster.
The events at Fukushima had been foretold in an investigation published in the U.S. two decades ago. The 1990 report by the U.S. Nuclear Regulatory Commission, an independent agency responsible for safety at the country’s power plants, identified earthquake-induced diesel generator failure and power outage leading to failure of cooling systems as one of the “most likely causes” of nuclear accidents from an external event.
Japan’s Trade Ministry, which oversees the nuclear power industry, dismissed evidence two years ago from geologists that the power station’s stretch of coast was overdue for a giant wave, minutes from a government committee show, Bloomberg News reported March 28. Tokyo Electric engineers also didn’t heed lessons from the 2004 tsunami off Indonesia that swamped a reactor 2,000 kilometers (1,200 miles) away in India, even as they advised the nuclear industry on coping with the dangers.
The Fukushima Dai-Ichi plant was “only designed to withstand tsunami of waves of a maximum of 5.7 meters,” the IAEA report said. “The larger waves that impacted the facility that day were estimated to be larger than 14 meters.”
The utility known as Tepco said April 10 that the March 11 earthquake generated a tsunami as high as 15 meters (49 feet). The base of the station is about 10 meters above sea level.
“The operators were faced with a catastrophic, unprecedented emergency scenario with no power, reactor control or instrumentation, and in addition to this, severely affected communication systems both within and external to the site,” the IAEA said. The report called on nuclear plant operators worldwide to learn from the Fukushima crisis and improve safety.
“Japan’s response to the nuclear accident has been
exemplary, particularly illustrated by the dedicated, determined and expert staff working under exceptional circumstances,” the report said.
Nuclear power can exist even amid natural disasters as long as the safety of reactors is secured, Mike Weightman, the leader of the IAEA fact-finding team in Japan, said at a news conference.
“We cannot predict natural disaster precisely, but you can try to predict the consequence of it,” Weightman said at a news conference in Tokyo today. “That’s the lesson taken way to the world.”
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