26 March 2018

Japan: Genkai‑3 Restarted After 7‑Year Outage

Japan: Genkai-3 Restarted After 8-Year Outage

WNISR, 26 March 2018

Genkai-3 was reconnected to the grid 25 March 2018, more than seven years after it shut down in December 2010. The 1180 MWe Pressurized Water Reactor (PWR), owned by the Kyushu Electric Power Company, is located in Genkai town, Saga Prefecture in southern Kyushu. Restart of the Genkai reactor had been delayed by two months due to the Kobe Steel scandal, where parts supplied to Kyushu Electric were required to be checked prior to restart. It is Kyushu Electric’s third reactor to resume operations, after Sendai units 1 & 2. Both Genkai units 3 & 4 passed Nuclear Regulation Authority (NRA) basic design approval in January 2017 and detailed design approval in August 2017.

Local approval for restart was secured for Genkai in April 2017. However, four of the eight municipalities in three prefectures (Saga, Fukuoka and Nagasaki) within 30 km of the Genkai plant had expressed opposition to restart. On 20 March 2018, the Saga District Court rejected a temporary injunction against the restart of Genkai units 3 & 4. A group of about 70 citizens in Saga and four other prefectures filed a request for the provisional injunction in January 2017. The residents provided evidence that Kyushu Electric had underestimated the potential impact of earthquakes and volcano eruptions on the plant. NRA safety guidelines require a volcano assessment for all volcanoes within a 160-kilometer radius from nuclear plants. The active volcano Mount Aso is 130 km from Genkai. Kyushu Electric stated there is a low probability that the volcano will erupt while the plant is in operation, which the court accepted, and that the plant has appropriate safety measures to meet seismic impacts. The plaintiffs are planning to appeal to the Fukuoka High Court.

In 2009, Genkai-3 became the first commercial reactor in Japan to operate with a partial plutonium-uranium mixed oxide (MOX) fuel core. Shutdown in 2010 for maintenance, in March 2011, Genkai-3 was loaded with 16 assemblies of MOX fuel supplied by the French company AREVA (now ORANO), bringing the MOX fuel core to 32 assemblies. The reactor was not restarted following the Fukushima Daiichi accident and the unirradiated 16 MOX assemblies containing 640 kg of plutonium was unloaded in 2013.

Citizens opposed to the operation of the Genkai reactor using MOX fuel had filed evidence in 2010 of the risk of fuel cladding gap reducing the safety margins of the reactor. In March 2015, the Saga district court ruled against the plaintiffs citing that they had failed to demonstrate a safety risk.

The restart of Genkai-3 brings to seven the number of reactors that have resumed operation since applying for NRA safety review in July 2013. Five reactors are currently operating, three owned by Kansai Electric Power Company (KEPCO), including Ohi-3 which restarted on 16 March 2018; Kyushu Electrics Sendai-1 is in extended outage for maintenance and Shikoku Electric Power Company’s Ikata-3, which was in maintenance outage at the time, was ordered shutdown in December 2017 by the Hiroshima High Court due to inadequate defense against volcanic eruption. This means that 29 reactors remain in Long Term Outage (LTO) since none of these have generated electricity during recent years. WNISR considers that all 10 Fukushima units are closed and will never restart.