Unit 3 of the Ohi nuclear power plant in Japan's Fukui Prefecture today resumed commercial operation, Kansai Electric Power Company announced. The reactor is the sixth to be restarted after clearing the country's revised safety regulations.

Ohi units 3 and 4 (Image: Kansai)

Following the shutdown of all of Japan's reactors after the March 2011 accident at the Fukushima Daiichi plant, Ohi 3 and 4 were given permission to resume operation in August 2012. However, the two 1180 MWe pressurised water reactors (PWRs) were taken offline again for Nuclear Regulation Authority (NRA) inspections in September 2013.

The NRA announced in May 2017 that the two units meet safety standards introduced in July 2013. The NRA approved Kansai's plan for strengthening the units in August last year. The regulator subsequently conducted pre-operation inspections of the units to confirm that the safety countermeasure equipment complies with the approved construction plan at the plant. The governor of Fukui Prefecture approved the restart of Ohi units 3 and 4 in November.

New reactors?

An energy advisory panel has included nuclear power as an option for Japan to meet its emissions targets for 2050, implying the possibility of the construction of new reactors, Reuters reported today.
The panel, whose recommendations will feed into a review by the Ministry of Economy, Trade and Industry (METI) of the country's 2030 basic energy plan and its measures to reduce carbon emissions by 2050. While recommending a reduction in Japan's reliance on nuclear, the panel includes nuclear as an option for long-term decarbonisation.
"The report does not specifically talk about possible building of new reactors or replacing existing reactors, but it does not deny such a possibility either," Shogo Tanaka, director of METI's energy strategy office was quoted as saying.

Kansai began loading the 193 fuel assemblies into the core of unit 3 on 9 February, completing the process on 13 February. The reactor was restarted on 14 March and attained criticality - a sustained chain reaction - the following day.

Kansai announced that Ohi 3 resumed commercial operation at 4.40pm today after completion of the final periodic outage inspection - the integrated plant performance test - by the NRA.

Kansai President and Director Shigeki Iwane said, "Taking this opportunity, I would like to express my sincere gratitude, in particular to members of the public in the host region, for deep understanding and generous support toward restart of the plant." He added, "We are committed to exerting every possible effort to gain more trust and understanding in the importance and safety of nuclear power generation from members of the public while making steady steps forwards to achieve and maintain safe plant operation after restarting operation."

Ohi 3 is the sixth of Japan's 42 operable reactors which have so far cleared inspections confirming they meet the new regulatory safety standards and have resumed operation. The others are: Kyushu's Sendai units 1 and 2; Shikoku's Ikata unit 3; and Kansai's Takahama units 3 and 4. Another 18 reactors have applied to restart.

Kansai began loading the fuel assemblies into the core of Ohi unit 4 yesterday. It expects to restart that unit around mid-May.

Kyushu Electric Power Company expects to restart both units 3 and 4 at its Genkai nuclear power plant in Saga prefecture later this year.