The restarted Ohi-4 achieved criticality at 3:00 a.m. on May 10 and the fission process has remained stable. On the 11th, it will connect to the grid, with full operation expected on the 14th. After final inspections by the Nuclear Regulation Authority (NRA), the unit will reenter commercial service in early June.

It is the eighth NPP at five NPP sites to be restarted under the new regulatory standards. The two most recent, in March, were the company’s Ohi-3 NPP (PWR, 1180MWe) and the Genkai-3 NPP (PWR, 1180MWe), owned and operated by the Kyushu Electric Power Co., in Genkai Town, Saga Prefecture.

Kansai EP had initially hoped to restart Ohi-4 in March. That target was delayed two months as a result of data falsifications on products at Kobe Steel Ltd. The Ohi-3 has already resumed commercial operation.