Nuclear Monitor #934
Jan van Evert, reporter WISE-Netherlands
On January 7th, Japans Nuclear Regulation Authority (NRA) announced that it was halting the screening needed to restart Chubu Electric Power’s Hamaoka Nuclear Power Station Units 3 and 4. The plant is located about 200 kilometres west of Tokyo on a coastal area known for its potential risks from so-called Nankai Trough megaquakes. A whistleblower already alerted the NRA in February of last year, but the issue only became public early January this year. The NRA decided to conduct on-site inspections at the headquarter of the Chubu Electric Power Co. in Nagoya, as well as to demand the company to submit materials concerning the details and background of the wrongdoing, and a report from its third-party committee detailing the facts of the misconduct and measures to prevent the recurrence. NRA chairman Shinsuke Yamanaka said: “Ensuring safety is the first and foremost responsibility for nuclear plant operators and (data fabrication) is an act of betrayal to their task and one that destroys nuclear safety”. The NRA has scrapped the entire review process for the Hamaoka reactor Units 3 and 4, and will issue a notice to other nuclear plant operators, urging them to ensure their application materials are prepared appropriately. It has also begun investigating other nuclear power plant operators for similar misconduct.
Chubu Electric Power had applied for the safety screening to resume operations at the two reactors in 2014 and 2015. Chubu Electric President Kingo Hayashi acknowledged that workers at the utility used inappropriate seismic data with an alleged intention to underestimate seismic risks. He apologized and pledged to establish an independent panel for investigation.
The company issued a press release describing in detail how it manipulated the seismic safety data. Risks were evaluated at least in part by scaling up the ground motion using data from smaller earthquakes. This is an inexact process, so the standard approach is to create a group of twenty different upscaled earthquake motions and find the one that best represents the average among the twenty. Of Japan’s 57 commercial reactors, less than a quarter (13) are currently in operation, 20 are offline and 24 others are being decommissioned, according to NRA. The Japanese government wants to restart several nuclear power plants, so this incident is a major setback.
The Citizens’ Nuclear Information Center (CNIC), a Japanese anti-nuclear group, issued a statement in which they called the situation ‘absolutely unacceptable’. They point out that ‘the NRA failed to detect the deterioration of safety culture at Chubu Electric’.
The Federation of Electric Power Companies of Japan warned its members that the situation was a “gravely serious matter that could shake the very foundations of the industry”, urging them to ensure proper operations.
Sources:
https://cnic.jp/english/?p=8865
https://www.asahi.com/ajw/articles/16283721?msockid=22a7eb873bfc69811cc0f8d83a86686e
