Trust in Japan’s nuclear watchdog, the Nuclear Regulation Authority (NRA), has been jolted. At hand is an issue raised by Kunihiko Shimazaki, former acting chairman of the NRA. Shimazaki pointed out that Kansai Electric Power Co. underestimated the maximum shaking that could occur during an earthquake at its Oi Nuclear Power Plant in Fukui Prefecture. Shimazaki is an authority on seismology, having formerly served as president of the Seismological Society of Japan. While serving in the NRA, he handled screening of power companies’ earthquake predictions for nuclear power plants including the Oi nuclear plant. After he stepped down two years ago, he re-examined data and found the method of calculating standard ground motion (the maximum shaking that would occur during an earthquake) was inappropriate in some cases, depending on the type of fault. This could lead power companies to underestimate figures, he apparently found in his research.
Mainichi 25th July 2016 read more »