Japan NRA Blasts Chubu Electric over N-Plant Data Fraud

Tokyo, Jan. 7 (Jiji Press)–Shinsuke Yamanaka, chief of Japan’s Nuclear Regulation Authority, on Wednesday denounced Chubu Electric Power Co. for cherry-picking earthquake risk data for its Hamaoka nuclear power plant in Shizuoka Prefecture, central Japan. “It is a fabrication of screening data directly related to (nuclear plant) safety and a clear misconduct,” Yamanaka said at a regular meeting of the nuclear watchdog. The NRA will suspend its inspection of the Hamaoka plant for its possible restart, he said. At its next regular meeting Jan. 14, the NRA will discuss whether it should seek a report from Chubu Electric or have its secretariat conduct an on-site probe, based on the nuclear reactor regulation law. Chubu Electric was found to have selected data that underestimated earthquake risk for the Hamaoka plant, located in the city of Omaezaki, for submission to the NRA for its inspection. An NRA secretariat official, reporting the issue to Wednesday’s meeting, explained that in 2018, when the data cherry-picking occurred, the NRA was evaluating the seismic ground motion of an active fault close to the nuclear plant, suggesting that the misconduct took place when the NRA was examining the possibility of a quake that could have a significant impact on the plant site. Other NRA members also slammed Chubu Electric. “If this were research, it would be fabrication or falsification of data,” said Koshun Yamaoka, in charge of screenings regarding earthquakes and tsunamis. “The matter is serious and truly regrettable.” “The Hamaoka nuclear plant is located directly above where a Nankai Trough earthquake is expected to occur, and is in one of the areas of highest interest,” he continued. “I had believed that Chubu Electric was handling the matter sincerely, but I now feel deep disappointment.” The Nankai Trough lies off Japan’s central to southwestern Pacific coasts. A huge earthquake is expected to occur at the trough in the future. Tomoyuki Sugiyama, responsible for screening plant equipment and facilities, said wrongdoing such as the data cherry-picking ruins the sincere efforts of plant operators, regulators and local communities. Another member Reiko Kanda said the data fraud wasted public funds spent on the NRA screenings. According to Chubu Electric, it had explained to the regulatory watchdog that it adopted a method in which the average value of multiple seismic waves calculated under different conditions was taken as the representative wave. But the company began using a different method in and before 2018, and it intentionally designated a seismic wave different from the average value as the representative wave from around 2018. Chubu Electric applied for NRA screening of the Hamaoka plant’s No. 3 and No. 4 reactors between 2014 and 2015. In September 2023, the NRA broadly approved the company’s assumption that the maximum seismic ground motion would be 1,200 gal. END [Copyright The Jiji Press, Ltd.]