A Japanese prime ministerial envoy secretly promised to the United States that Japan would resume its controversial “pluthermal” program, using light-water reactors to burn plutonium, according to documents obtained by the Mainichi.
The secret promise was made by Hiroshi Ogushi, then parliamentary secretary of the Cabinet Office, to Daniel Poneman, deputy secretary of the U.S. Department of Energy, during Ogushi’s visit to the United States on behalf of then Prime Minister Yoshihiko Noda in September last year.
The revelation comes as Japan’s pluthermal project remains suspended in the wake of the Fukushima No. 1 Nuclear Power Plant disaster due to safety concerns. The fact that a Japanese official promised to the U.S. to implement such a controversial project without a prior explanation to the Japanese public is expected to stir up controversy.
According to the official documents obtained by the Mainichi, upon being pressed to reduce the amount of plutonium in Japan that could be diverted to military use, Ogushi told Poneman that Japan would burn plutonium in plutonium-thermal (pluthermal) reactors. The then ruling Democratic Party of Japan (DPJ) was in the final stages of formulating its nuclear energy policy at the time.
Under the pluthermal plan, spent nuclear fuel generated in light-water reactors is reprocessed to extract plutonium, which is then mixed with uranium to create mixed-oxide (MOX) fuel for use in power generation. However, many experts have raised questions about the program, citing its high costs and the risks posed by the fuel’s comparatively low melting point and the decreased effectiveness of control rods. The plan to burn plutonium in conventional reactors was introduced in 2009 because there were no prospects for putting the Monju prototype fast-breeder reactor into practical use.
The documents that the Mainichi obtained are a compilation of cables recording the Ogushi-Poneman talks in the U.S. on Sept. 12 last year. During the meeting, Ogushi explained that Japan would inject all available policy resources to break away from nuclear power generation in the 2030s, that it would steadfastly promote the nuclear fuel cycle program in the medium and long term, and that Japan would end research on the Monju reactor after confirming its achievements. The explanation was in accordance with the government’s Innovative Strategy for Energy and the Environment, which was finalized on Sept. 14.
The promotion of a nuclear fuel cycle implies extraction of plutonium from spent nuclear fuel at the Rokkasho Reprocessing Plant in Aomori Prefecture. But Japan’s “zero nuclear power” policy and the suspension of the Monju reactor could leave the nation without a facility to burn plutonium. Poneman expressed concern that this would create a situation in which plutonium could be diverted to military use. In response, Ogushi promised the continuation of the pluthermal program to burn plutonium in light-water reactors.
During an interview with the Mainichi, Ogushi declined to reveal the details of the meeting, saying, “I can’t disclose whom I met from a diplomatic standpoint.” He added that he didn’t remember the pluthermal issue.
The Innovative Strategy for Energy and the Environment states that “nuclear reactors whose safety has been confirmed will be utilized,” but contains no reference to pluthermal plans.
Yukio Edano, a House of Representatives legislator who was serving as economy, trade and industry minister at the time, defended Ogushi, saying Japan had made no distinction between pluthermal and conventional reactors that were to be operated. “There were no such micro-level talks in the Energy and Environment Council. I would have given the same answer (if I had visited the U.S.),” he said.
The current administration led by Prime Minister Shinzo Abe also upholds a policy to resume the pluthermal program, according to documents obtained by the Mainichi that were produced by the Ministry of Economy, Trade and Industry on March 1 and submitted to minister Toshimitsu Motegi. The documents clearly state that the government will “promote the use of MOX fuel in light-water reactors (pluthermal) after reprocessing (nuclear fuel) at the Rokkasho Reprocessing Plant.” Based on the content of the documents, Motegi stated at a lower house Committee on Economy, Trade and Industry session on March 22, “We will steadily promote the pluthermal plans.”
Despite the country not knowing which nuclear reactors will be authorized to resume operations following the July implementation of the new regulatory standards, the government has been pushing ahead with its plans to restart the controversial pluthermal program.
“It is abnormal for sure,” said one official with the Agency for Natural Resources and Energy. “But it can’t be helped if the Rokkasho plant is to be put into operation.”