The No. 3 reactor of Kansai Electric Power Co.'s Takahama nuclear power plant in Fukui Prefecture, which was restarted in late January, is expected to start commercial operations in late February. Its No. 4 reactor is also set to be restarted around the same time. Although the Takahama Municipal Government and Fukui Prefecture gave their consent to the restart, there are serious concerns, including those expressed by nearby municipalities and their residents.

Following the restart of the No. 1 and No. 2 reactors at Kyushu Electric Power Co.'s Sendai nuclear power plant in Kagoshima Prefecture, Takahama unit 3 is the third reactor to come back online under the safety regulations introduced by the Nuclear Regulation Authority following the shutdown of the nation's nuclear plants in the wake of the March 2011 disaster at Tokyo Electric Power Co.'s Fukushima No. 1 plant. But it is the first to run on mixed oxide (MOX) fuel, which contains not only uranium but also plutonium extracted from spent nuclear fuel. The No. 4 reactor at Takahama will also use MOX fuel.

Japan has accumulated 48 tons of plutonium — enough to make an estimated 6,000 nuclear bombs — as a result of the government's nuclear fuel cycle policy, which aims to reprocess spent fuel to extract uranium and plutonium to be used again as fuel. The Takahama restart may help the government show its resolve to cut its plutonium stockpile to address U.S. concerns over nuclear proliferation. But the restart will pose a problem in the not-too-distant future. The spent fuel storage facilities for reactors 3 and 4 are expected to become filled in seven or eight years after they are reactivated. Spent uranium fuel from nuclear power plants is to be sent to a fuel reprocessing facility in Rokkasho, Aomori Prefecture, still on a trial run, but the plant cannot reprocess used MOX fuel — meaning that there will be no place to store overflowing spent fuel from the Takahama reactors. Although Kansai Electric aims to choose a site for a medium-term storage facility outside Fukui by around 2020, no prefectures seem willing to host it.