Chubu Electric N-Plant Screening to Be Scrapped: NRA Chief

Tokyo, Jan. 7 (Jiji Press)–Shinsuke Yamanaka, chief of Japan’s Nuclear Regulation Authority, said Wednesday that he expects the NRA’s screening of Chubu Electric Power Co.’s Hamaoka nuclear power plant in Shizuoka Prefecture, central Japan, for a possible restart will be scrapped. “I expect the screening process to go back to square one,” he told a press conference. His statements came after Chubu Electric was found to have cherry-picked data that underestimated earthquake risk for the Hamaoka plant, located in the city of Omaezaki, for submission to the NRA for its inspection. “We need to redo the screening itself,” Yamanaka said, adding that the nuclear watchdog’s secretariat should conduct an on-site probe into the power company. At a regular NRA meeting held earlier in the day, Yamanaka said that Chubu Electric’s actions were “a fabrication of screening data directly related to (nuclear plant) safety and (therefore) clear misconduct.” The NRA will suspend its screening of the Hamaoka plant, he said. The watchdog is expected to reach a formal decision on its next move at its next regular meeting Jan. 14. An NRA secretariat official, reporting 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 coast. 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 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. The company began using a different method in and before 2018, however, 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.]