Ohi‑4, Down Since 2013, Finally Reconnected to the Japanese Grid

Ohi-4, Down Since 2013, Finally Reconnected to the Japanese Grid

WNISR, 12 May 2018

The Ohi unit 4 reactor was reconnected to the grid 11 May 2018, plant owner Kansai Electric Power Company (KEPCO) announced. The reactor, located on Wakasa bay, Fukui Prefecture in western Japan, last operated on 14 September 2013. KEPCO had planned to restart in March 2018, but had to delay for two months due to the need for inspections following the disclosure of data falsifications on products supplied by Kobe Steel Ltd.

Unit 3 at Ohi was reconnected to the grid on 16 March 2018, four and a half years after it was shut down on 2 September 2013. Commercial operations of both Ohi reactors are projected to help KEPCO reduce its fuel costs by about ¥120 billion (US$1.09 billion) a year.

A major issue at the Ohi site is the status of geologic faults within the site and the area around it. The seismic issue was a central element that led on 22 May 2014 to the Fukui District Court issuing a landmark ruling against the operation of the Ohi reactors, the case was not an injunction as there was no plan for immediate restart. The Fukui Court ruled in favor of 200 plaintiffs, who contended that the plant was not sufficiently robust against active seismic faults and that the acceleration at the site could exceed the very high level of 1,260 gal.

Kunihiko Shimazaki, the former Nuclear Regulation Authority (NRA) deputy chair and a professor emeritus of seismology at the University of Tokyo, in July 2016, voiced strong concerns related to the Ohi reactors and his “sense of crisis” over the approach to earthquake risk analysis by the NRA.

The restart of Ohi-3 brings to seven the number of reactors that have resumed operation since applying for NRA safety review in July 2013. The four reactors currently operating are all owned by KEPCO, while Sendai units 1&2 are in outage for maintenance, while 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 in Japan remain in Long Term Outage (LTO) since none of these have generated electricity during 2014 or 2015. WNISR considers that all 10 Fukushima units are closed and will never restart.