Unit 3 at Kansai Electric Power Company’s Ohi NPP in Japan’s Fukui Prefecture began commercial operation on 10 April. Ohi 3 and 4, both 1,180MWe pressurised water reactors (PWRs), were the first two reactors to resume operation in August 2012 following the 2011 Fukushina Daiichi accident, but were closed in September 2013 for scheduled refuelling and maintenance. The Nuclear Regulation Authority (NRA) announced in May 2017 that both units met the more stringent safety standards introduced in July 2013. NRA approved Kansai's plan for strengthening the units last August and subsequently conducted pre-operation inspections to confirm that the safety countermeasure equipment complied with the approved construction plan at the plant. The governor of Fukui Prefecture approved the restart of Ohi 3 and 4 in November and Kansai loaded the 193 fuel assemblies into the core of unit 3 in February. The reactor achieved criticality on 15 March before undergoing a series of performance tests.

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 Electric's Sendai NPP units 1 and 2; Shikoku Electric'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 on 9 April and expects to restart the unit in mid-May. Kyushu Electric Power Company expects to restart units 3 and 4 at its Genkai NPP in Saga prefecture later this year.