Japan's Nuclear Regulation Authority (NRA) has officially approved Tokyo Electric Power Company’s (Tepco’s) construction plan for an anti-terrorism facility at units 6&7 of its Kashiwazaki-Kariwa NPP in Niigata Prefecture. Unit 7’s main facility has already passed the NRA safety screening needed for its restart and Tepco has been working on bringing the reactor back online.

However, in April 2021, NRA issued a de facto ban on operations at the Kashiwazaki-Kariwa plant after a series of security flaws were identified. The problems included the Tepco’s failure to repair malfunctioning equipment to detect intruders. NRA then considered whether it should proceed with its examination of Tepco’s plan for the antiterrorism facility's construction. Nevertheless, in July this year, NRA approved a draft report stating that the construction plan met the new safety standards introduced after the March 2011 triple meltdown at the Fukushima Daiichi NPP. However, the order banning operation has not been lifted.

At its recent regular meeting, NRA Chairman, Toyoshi Fuketa, said that the approval of the construction plan for the antiterrorism facility "was to confirm whether Tepco's basic plan is appropriate” and that it “has nothing to do with the possible removal of the order ".

Tepco said it “will continue to respond carefully to NRA reviews as we strive to further improve safety and reliability based on the lessons we have learned from the Fukushima Daiichi Nuclear Power Station accident”.

Tepco has long wanted to resume operation of the Kashiwazaki-Kariwa plant to reduce its dependence on costly fossil fuel imports for non-nuclear thermal power generation. It is also facing huge compensation payments and other costs stemming from the 2011 Fukushima Daiichi accident. The seven-unit Kashiwazaki-Kariwa complex was one of the world's largest NPPs with a combined output capacity of 8, 210MWe when it was fully operational. Units 6&7 had cleared safety screenings by the NRA in 2017, paving the way for the resumption of operations. However, the security breaches and delays in completing safety upgrades have caused delays.

Although Kashiwazaki-Kariwa was unaffected by the March 2011 earthquake and tsunami all seven of the plant’s reactors had been offline for two to three years following the 2007 Niigata-Chuetsu earthquake, which caused damage to the site. Work has since been carried out to improve the plant's earthquake resistance.

Tepco applied for NRA approval of its design and construction plan for Kashiwazaki-Kariwa units 6&7 (1356MWe advanced boiling water reactors) in September 2013. It submitted information on safety upgrades across the site and at those units, which began commercial operation in 1996 and 1997 and were the first Japanese boiling water reactors to be considered for restart.

Image: The Kashiwazaki-Kariwa nuclear power plant (courtesy of Tepco)