Strains Seen in Japan’s Plutonium Policy

Daniel Horner

Japan’s recently proposed energy strategy is not clear on how to address fundamental policy questions on the country’s approach to spent nuclear fuel, reprocessing, and plutonium use, a Japanese official and a U.S. nuclear expert said in interviews last month.

On Sept. 14, the Japanese government issued an energy strategy document that contemplates the phase-out of nuclear power by about 2040. A cabinet decision five days later made clear that the strategy document did not constitute a binding policy decision, and the strategy could be scrapped entirely if the current Japanese government falls from power in the upcoming elections, which are expected to take place by next summer.

The new energy strategy is part of Japan’s response to the accident at the Fukushima Daiichi nuclear reactors on March 11, 2011.

For decades, a central part of Japan’s nuclear plans has been what energy and nonproliferation specialists call “closing the fuel cycle.” That involves reprocessing the spent fuel from power reactors to separate plutonium that is then used in making fresh fuel for reactors.

The strategy document says “it is necessary…to tackle squarely” the question of what to do with spent fuel, but does not make specific commitments in that regard. It commits Japan to “continu[ing] its present nuclear fuel cycle policy,” although it adds a few caveats.

“We have not decided anything important” with regard to the plutonium program, the Japanese official said in an Oct. 25 interview. In fact, he said, the policy contains some “contradictory” elements.

For example, the Rokkasho reprocessing plant, where Japan plans to reprocess spent fuel from its power plants, has been authorized to operate beyond the year 2050, but the strategy does not explain how reprocessing will continue if the nuclear power plants that would consume the plutonium separated at Rokkasho have been shut down, he said.

The Rokkasho plant has faced many problems and has not begun commercial operation; the current estimate for its startup is October 2013. Japan has shipped much of its spent fuel to France and the United Kingdom for reprocessing. Of the approximately 44 metric tons of separated plutonium that Japan owns, about nine metric tons are in Japan, with the remaining 35 metric tons roughly evenly split between the two European reprocessors, according to the most recent figures released by Japan.

International Sensitivities

In an Oct. 19 interview, Charles Ferguson, president of the Federation of American Scientists, said Japanese officials are “acutely aware” of the potential concerns in Asia and elsewhere raised by the plutonium surplus. There have been “numerous discussions” with the U.S. government on the issue, said Ferguson, who is co-chairman of the Maureen and Mike Mansfield Foundation’s U.S.-Japan Nuclear Working Group.

Japanese media have reported that, at a meeting in September, U.S. Deputy Energy Secretary Daniel Poneman encouraged Japanese officials to minimize the amount of plutonium they stockpiled.

In an Oct. 17 e-mail to Arms Control Today, a Poneman aide declined to comment on “the specifics of diplomatic discussions.” With regard to the U.S. policy on reprocessing and plutonium use, she said it is up to the Japanese government to make the decision and “the United States is eager to help in any way Japan finds useful as it explores its future approach to nuclear power.” The United States has proposed that the two countries discuss “the non-proliferation and security aspects of the new nuclear energy policy,” she said.

Domestic Commitments

Ferguson and the Japanese official stressed that the domestic politics of Japan’s fuel cycle are complicated and likely to play a major role in whatever decision the country ultimately makes in that area.

As the two men described it, one of the inducements to the residents of Aomori to agree to host the Rokkasho plant was that it would not become a long-term repository for spent fuel and radioactive waste. Yet, the official said, nuclear operators in Japan also made a commitment to the localities hosting nuclear power plants that they would not have to store spent fuel on-site indefinitely and could transfer it eventually to a reprocessing plant such as the Rokkasho facility. That combination of commitments does not give policymakers much latitude on fuel cycle policy, regardless of what decisions they make with regard to nuclear power, he said.

In addition to plutonium, reprocessing produces so-called high-level waste, which also requires a repository. A key question for Japanese fuel-cycle policy is where the country will decide to locate this facility, Ferguson said.

In part because of the uncertainties about the size of the Japanese reactor fleet in the coming years, it is unclear how rapidly the separated plutonium could be consumed. Ferguson and the official said one option being discussed is to develop fast-neutron reactors, which are capable of “breeding” more plutonium than they consume but also can be used to “burn” plutonium more efficiently than light-water reactors can.