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Friday, May 7, 2010

Troubled Monju reactor revived in Fukui

Fast-breeder technology gets second chance


Staff writer

OSAKA — Monju, a nuclear reactor designed to generate more plutonium than it burns, resumed operation Thursday morning in Tsuruga, Fukui Prefecture, 14 years and five months after a sodium coolant leak and subsequent fire inside the plant shut it down.

News photo
One more time: The Monju fast-breeder reactor in Tsuruga, Fukui Prefecture, shut down by a sodium-leak accident and coverup in 1995, is restarted Thursday as Mayor Kazuharu Kawase (below left) and Japan Atomic Energy Agency head Toshio Okazaki watch from the control room. KYODO PHOTO
News photo

The restart of the so-called fast-breeder reactor marks the start of the government's second attempt to complete a long-delayed program aimed at using such reactors to reduce Japanese dependence on foreign oil.

But antinuclear activists warn of safety problems while scientists and others are concerned about the increased nuclear proliferation risks that fast-breeders represent. They say the troubled Monju is setting a bad example at the Nonproliferation Treaty talks now taking place in New York.

The Japan Atomic Energy Agency, which operates Monju, said the reactor was started up at 10:36 a.m. The reactor is expected to reach criticality — the point when a nuclear reaction becomes self-sustaining — by Saturday.

Monju's power output will be raised gradually as further checks are conducted until it reaches about 40 percent by May 2011 and 100 percent by the second half of 2012.

Then, following further technical checks expected to be completed by the first half of 2013, Monju will be running at full bore, agency officials said.

"When operating the plant, it should be 'safety first,' and that should make the people of Fukui proud," Fukui Gov. Issei Nishikawa told reporters in the morning.

Nishikawa gave his approval to restart Monju late last month after getting reassuring signals from the central government over his requests for assistance on local transportation projects — particularly in regard to an extension of the Hokuriku bullet-train line that is expected to link Tokyo with Kanazawa in Ishikawa Prefecture by spring 2015.

Nishikawa and Fukui officials want the line extended through the city of Fukui down to Tsuruga.

Monju, which can generate up to 280 megawatts, is the prototype for a nationwide chain of commercial fast-breeder reactors that would burn a special mixture of uranium and plutonium oxides known as MOX. The fuel is designed to create more plutonium than consumed when burned, leading to a theoretically endless supply of nuclear fuel.

Current plans call for the commercialization of fast-breeder reactors by 2050 at the latest.

Monju's restart comes less than two weeks after safety concerns were raised again when a faulty coolant detector was discovered in the reactor's auxiliary building. The detector was quickly repaired and officials said no leak was detected.

But antinuclear activists warned Thursday that serious safety questions remain over the condition of the equipment and whether the plant is ready to withstand an earthquake, saying there is no precedent anywhere in the world for restarting a fast-breeder reactor that has been idle for so long.

"Monju has been shut down since December 1995. Over the ensuing 14 years, equipment and piping have aged. The Japan Atomic Energy Agency says there are no problems with Monju's equipment, but visual inspections were carried out on only a small fraction of the inside of Monju's extensive piping," said Hideyuki Ban, codirector of the Tokyo-based NGO Citizens' Nuclear Information Center.

Miwako Ogiso, a Fukui Prefecture-based activist who has fought the Monju plant for more than three decades, said local residents are particularly concerned about whether the reactor can withstand an earthquake.

Since 1995, two seismic fault lines near Monju have been discovered, while the plant was built to earthquake standards established three decades ago.

In July 2007, a magnitude-6.8 earthquake struck the Niigata area, forcing the closure of the Kashiwazaki-Kariwa nuclear power plant. The magnitude exceeded predictions and forced the government to adapt new standards when evaluating seismic safety. In 1948 as well, an earthquake in Fukui, about 60 km from Tsuruga, struck with a magnitude of 7.1, killing nearly 3,700 people.



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