Chubu Electric files report on seismic data irregularities

Chubu Electric Power has submitted a report to Japan’s nuclear regulator detailing irregularities in earthquake risk data at its Hamaoka nuclear power station in Shizuoka prefecture, according to Jiji Press.

The Nuclear Regulation Authority had set a March 31 deadline for the submission covering the facts of the case, while reports addressing the causes of the issue remain without a specified timetable.

The utility said it had been selecting representative seismic waves using methods that differed from those presented to the regulator since at least 2018. It also acknowledged deliberately choosing seismic waves that did not reflect average values.

These practices prompted concerns that the company may have underestimated the seismic ground motion the plant could face. According to reports, the regulator first became aware of the issue following an external tip in February 2025. Chubu Electric disclosed the irregularities publicly in January this year.

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