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Japanese Experts Question Safety of—and Need for—Nuclear Power

27 January 2012 12:00 pm
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Dennis Normile

Nuclear plant designer Masashi Goto (left) and materials scientist Hiromitsu Ino (right) have raised questions about plans to restart two reactors.

TOKYO—Japan is preparing for the possibility of a summer without nuclear power as utilities and safety experts squabble over the safety of the country's remaining reactors. And a key government minister is calling the power industry's bluff—that blackouts will occur if plants idled for inspection are not brought online—by saying the nation could avoid disruption by relying on conservation and thermal power.

By law, nuclear power plants must be periodically shut down for maintenance and inspection; utilities need national and local permission to restart operations. In the wake of the Fukushima disaster, last summer the governing Democratic Party of Japan required "stress tests," analyses of a facility's ability to withstand natural disasters, to be part of the periodic inspection routine. That analysis was carried out for two reactors at a plant in Ohi on the Japan Sea coast and submitted for review to Japan's Nuclear and Industrial Safety Agency (NISA), which concluded they had passed. Operator Kansai Electric Power is seeking approval to restart the two reactors.

But today two members of a NISA advisory committee called the stress tests flawed and "not proof of safety." At a press conference, Hiromitsu Ino, a materials scientist and professor emeritus at the University of Tokyo, and Masashi Goto, a former nuclear power plant designer, said their concerns were simply ignored in the final report.

Ino said there are nine issues the stress tests failed to address. He said the criteria for the tests should reflect lessons learned from the Fukushima disaster, but that the studies into the sequence of events that led to the cascade of failures are ongoing. Without the results of those studies, he says, the criteria being used are "subjective and unclear." He notes that the stress tests called for checking facility resistance to shaking 1.8 times the design earthquake, yet seismologists have noted that those design events are based on the historical record and it is now clear that much more powerful earthquakes have occurred over geologic time. The analyses also do not consider the inevitable degradation over time of a reactor's materials.

Meanwhile, Economy, Trade and Industry Minister Yukio Edano was reported in this morning's Asahi Shimbun (newspaper) as saying it is conceivable that none of the country's nuclear power plants will be operating this summer because of the difficulty of gaining local approval to restart. Of Japan's 54 nuclear reactors, only three are currently operating, and they must shut down for periodic inspection by the end of April.

Although gaining local approval is not legally required, Edano's comments indicate that the national government might support the stance of local officials, which puts a very high hurdle in front of the utilities. The governor of Fukui Prefecture, which hosts the Ohi nuclear power plant, is on record as opposing the restart of any commercial nuclear power plants. "I am hoping that in this situation decisions will reflect what local people want," Ino said.

Edano told the newspaper that thermal power and conservation efforts should get the country through the summer without the cutbacks and blackouts imposed last year. He added that his ministry is working on countermeasures to handle reduced power output.

A new national energy policy is due by the end of the summer, and observers expect it could call for a phase-out of nuclear power. A sudden and permanent shut down of all reactors, however, would be a huge surprise.

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