The Monju prototype fast-breeder reactor — a long-troubled national project — has been in a precarious state of shutdown since a 3.3-ton device crashed into the reactor’s inner vessel, cutting off access to the plutonium and uranium fuel rods at its core.
Engineers have tried repeatedly since the accident last August to recover the device, which appears to have gotten stuck. They will make another attempt as early as next week.
But critics warn that the recovery process is fraught with dangers because the plant uses large quantities of liquid sodium, a highly flammable substance, to cool the nuclear fuel.
The Monju reactor, which forms the cornerstone of a national project by resource-poor Japan to reuse and eventually produce nuclear fuel, shows the tensions between the scale of Japan’s nuclear ambitions and the risks.
The plant, a $12 billion project, has a history of safety lapses. It was shuttered for 14 years after a devastating fire in 1995, one of Japan’s most serious nuclear accidents before this year’s crisis at the Fukushima Daiichi Nuclear Power Station. Prefecture and city officials found that the operator had tampered with video images of the fire to hide the scale of the disaster. A top manager at the plant recently committed suicide, on the day that Japan’s atomic energy agency announced that efforts to recover the device would cost almost $21.9 million. And, like several other reactors, Monju lies on an active fault.
Even if the device can be removed, restarting the reactor will be risky, given its safety record and its use of highly toxic plutonium as fuel, said Hideyuki Ban, co-director of the Citizens’ Nuclear Information Center, a watchdog group, and a member of an advisory government committee on Japan’s long-term nuclear energy policy. The plant is 60 miles from Kyoto, a city of 1.5 million people, and the fast-breeder design of the reactor makes it more prone to Chernobyl-type runaway reactions in the case of a severe accident, critics say.
“Let’s say they make this fix, which is very complicated,” Mr. Ban said. “The rest of the reactor remains highly dangerous. And an accident at Monju would have catastrophic consequences beyond what we are seeing at Fukushima.”
Japan badly needs sources of energy. By closing the loop on its nuclear fuel cycle, Japan aims to reuse, recycle and produce fresh fuel for its 54 reactors.
“Monju is a vital national asset,” said Noritomo Narita, a spokesman here in Tsuruga for the reactor’s operator, the government-backed Japan Atomic Energy Agency. “In a country so poor in resources, such as Japan, the efficient use of nuclear fuel is our national policy, and our mission.”
Critics have been fighting the project since its inception in the 1970s. “It’s Japan’s most dangerous reactor,” said Miwako Ogiso, secretary general of the Council of the People of Fukui Prefecture Against Nuclear Power. “It’s Japan’s most nonsensical reactor.”
After promises of safety upgrades, as well as lavish subsidies and public works, the government has wooed local officials into allowing a restart of the reactor. In Fukui, the government had ready allies: with 14 nuclear reactors, it is Japan’s most nuclear-friendly prefecture. (Fukushima, in second place, has 10 reactors.)
Monju was reopened in May 2010, and just three months later, the 3.3-ton fuel relay device fell into the pressure vessel when a loose clutch gave way. In the two decades since the reactor started tests in 1991, the atomic energy agency has managed to generate electricity at the reactor only for one full hour.
In Monju, Japan is pursuing a technology that most countries have long abandoned. Decades ago, a handful of countries, including the United States, started exploring similar programs. But severe technical difficulties, as well as fears about the weapons-grade plutonium that the cycle eventually produces, have led most countries to scrap their programs.
But Japan has remained staunchly committed to the Monju project. The government of Prime Minister Naoto Kan has shielded it from the deep cuts in spending that it has required of other national projects since it came to power in September 2009.
Under a government plan, Japan would use technology developed at Monju to commercialize fast-breeder reactors by 2050.
Mr. Kan has recently hinted at an overhaul of Japan’s nuclear policy, though he has not commented specifically on the fate of the Monju reactor.
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