Oi No. 4 N-Reactor Restarted after Halt of Nearly 5 Years

May 10, 2018

Oi, Fukui Pref.- Kansai Electric Power Co. restarted the No. 4 reactor at its Oi nuclear plant in Fukui Prefecture, central Japan, on Wednesday, after a suspension of four years and eight months.

The reactor, which was halted in September 2013 for regular checkups, is the eighth to have been reactivated under the country's new nuclear plant safety standards, introduced in the wake of the March 2011 triple-meltdown accident at Tokyo Electric Power Company Holdings Inc.'s <9501> tsunami-stricken Fukushima No. 1 nuclear plant.

Work to remove control rods from the Oi No. 4 reactor started at 5 p.m. (8 a.m. GMT). The reactor is expected to reach criticality, or a state of self-sustaining nuclear fission chain reaction, around 3 a.m. on Thursday and begin power generation and transmission on Friday. It is seen reaching full capacity around Monday.

Kansai Electric plans to put the No. 4 reactor into commercial mode in early June, and then to cut its electricity prices this summer.

Commercial operations of the No. 3 and No. 4 reactors at the Oi plant are projected to help reduce the firm's fuel costs by about 120 billion yen a year. The No. 3 unit was brought back online in March this year and entered commercial mode in April.

The utility lowered its electricity rates for households by 3.15 pct on average in August 2017, after it resumed commercial operations of the No. 3 and No. 4 reactors at its Takahama plant in Fukui.

As each of the two Oi reactors has a capacity of 1.18 million kilowatts, larger than 870,000 kilowatts for each of the Takahama reactors, the forthcoming rate cut may be steeper than the previous one, possibly bringing the company's electricity prices down to levels before the Fukushima nuclear accident, industry observers said.

Kansai Electric owns a total of 11 reactors--four each at the Oi and Takahama plants, and three at the Mihama plant, also in Fukui.

Besides the four in operations, four--the Mihama No. 1 and No. 2 units and the Oi No. 1 and No. 2 units--are set to be decommissioned, and the other three--the Mihama No. 3 unit and the Takahama No. 1 and No. 2 units--are undergoing work to allow them to continue to operate after reaching 40 years of service.

With the Oi and Takahama plants located as close as 13.5 kilometers from each other, the plant operator has been urged to draw up measures that should be taken in case accidents occur at the same time at the two facilities.

Around this summer, the Japanese government plans to carry out a comprehensive anti-disaster drill assuming such simultaneous accidents. Jiji Press