Japan's Nuclear Regulation Authority (NRA) on 14 April issued an order formally banning Tokyo Electric Power Company Holdings (Tepco) from restarting the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture, its largest nuclear plant, by barring Tepco from transporting nuclear fuel stored at the plant or loading it into the reactors. This followed a string of serious security violations.
In March, the Kashiwazaki-Kariwa plant was found to have been vulnerable to unauthorised entry at 15 locations since March 2020 because of defective intruder detection systems and backups. NRA provisionally rated the security breaches to be at the worst level in terms of safety and severity - the first time it has given such an assessment.
Tepco had 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, in addition to the latest security issues, safety upgrades have not yet been completed.
Tepco indicated earlier in April that it would accept NRA’s ruling. Tepco president Tomoaki Kobayakawa apologised for causing safety concerns and said he and three other company executives are taking 30% salary cuts for six months. “We take the problem seriously and will investigate the cause and pursue efforts to make drastic reforms,” he told a news conference.