Tue, Jan 01, 2013 - Page 9 News List

Japan’s growing plutonium stocks causing concern

Despite strong anti-nuclear power sentiment among Japanese caused by the 2011 nuclear disaster, the country will likely continue using atomic energy, meaning it must resolve the nagging issue of how to safely dispose of its nuclear waste

By Mari Yamaguchi  /  AP, ROKKASHO, Japan

Liberal Democrats have said they will spend the next 10 years figuring out the best energy mix, effectively freezing a nuclear phase out. Newly appointed Japanese Prime Mnister Shinzo Abe said he may reconsider the previous government’s decision not to build more reactors.

Construction at Rokkasho’s reprocessing plant started in 1993 and that unit alone has cost ¥2.2 trillion (US$27 billion) so far. Rokkasho’s operational cost through 2060 would be a massive ¥43 trillion, according to a recent government estimate.

The reprocessing facility at the extremely high-security plant is designed to extract uranium and plutonium from spent fuel to fabricate mixed oxide fuel (MOX) — a mix of the two radioactive elements. The MOX fabrication plant is set to open in 2016.

Conventional light-water reactors use uranium and produce some plutonium during fission. Reprocessing creates an opportunity to reuse the spent fuel rather than storing it as waste, but the stockpiling of plutonium produced in the process raises concerns about nuclear proliferation.

Fast breeder reactors are supposed to solve part of that problem. They run on both uranium and plutonium, and they can produce more fuel than they consume because they convert uranium isotopes that do not fission readily into plutonium. Several countries have developed or are building them, but none has succeeded in building one for commercial use. The US, France and Germany have abandoned plans due to cost and safety concerns.

The prototype Monju fast breeder reactor in western Japan had been in the works for nearly 50 years, but after repeated problems, authorities this summer pulled the plug after deeming the project unworkable and unsafe.

Monju successfully generated power using MOX in 1995, but months later, massive leakage of cooling sodium caused a fire. Monju ran another test in 2010, but stopped again after a fuel exchanger fell into the reactor vessel. Some experts also suspect that the reactor sits on an active fault line. An independent team commissioned by the Japanese Nuclear Regulation Authority is set to inspect faults at Monju early this year.

Japan also burned MOX in four conventional reactors beginning in 2009. Conventional reactors can use MOX for up to one-third of their fuel, but that makes the fuel riskier because the plutonium is easier to heat up. Three of the conventional reactors that used MOX were shut down for regular inspections around the time when the three Fukushima Dai-ichi reactors exploded and melted down following the earthquake and tsunami. The fourth reactor that used MOX was among the reactors that melted down. Plant and government officials deny that the reactor explosion was related to MOX.

Japan hopes to use MOX fuel in as many as 18 reactors by 2015, according to a brochure produced in November by Rokkasho’s operator, JNFL, a joint venture of nine Japanese nuclear plant owners. However, even conventionally powered nuclear reactors are unpopular in the country and using MOX would raise even more concerns.

When launched, Rokkasho could reprocess 800 tonnes of spent fuel per year, producing about 5 tonnes of plutonium and 130 tonnes of MOX per year, and would become the world’s No. 2 MOX fabrication plant after France’s Areva, Rokkasho’s operator said. The Japanese government and nuclear industry hope to use much of the plutonium at Oma’s advanced plant, which could use three times more plutonium than a conventional reactor.

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