Two senior executives at Chubu Electric Power, the operator of a nuclear power plant in central Japan, have announced their planned resignations following revelations of falsified earthquake data related to the plant’s safety assessments. President Kinjo Hayashi and Chairman Satoru Katsuno will step down as the company also decided to withdraw its applications to restart the Nos. 3 and 4 reactors at the Hamaoka nuclear power plant.
Chubu Electric disclosed the decision on Friday, shortly after receiving an independent panel’s 250-page report examining the misconduct. The report highlighted that management’s pressure on staff to expedite the restart review contributed to the data tampering. It also noted that internal whistle-blower reports made in 2019 and 2021 were improperly handled, allowing the falsification to continue undetected for years.
The Hamaoka nuclear plant, situated in Omaezaki, Shizuoka Prefecture, lies near a major seismic fault line where experts predict a potentially catastrophic "megaquake" could occur within years or decades. The safety assessment of this plant includes estimating the maximum seismic ground motion, a critical factor for designing earthquake-resistant nuclear reactors.
According to the investigative panel’s findings, the original falsification of seismic data began by 2012 and continued during Katsuno’s tenure as president, which lasted from 2015 until about 2020. Hayashi took on the presidency in April 2020, primarily coming from sales roles within the company, and expressed deep remorse during a news conference. He acknowledged a failure to foster an organizational culture that prioritizes compliance and safety above all else.
Japan’s nuclear energy sector has been under heightened scrutiny since the 2011 earthquake and tsunami triggered a meltdown at the Fukushima Daiichi plant, leading to a nationwide shutdown of nuclear reactors. However, the Japanese government has since sought to revive nuclear power as part of broader energy transition efforts aimed at reducing fossil fuel dependence, achieving carbon neutrality by 2050, and supporting growing energy demands driven by technologies such as artificial intelligence.
In September 2023, Japan’s Nuclear Regulation Authority (NRA) had approved Chubu Electric’s seismic ground motion estimate of 1,200 gal—a unit measuring quake acceleration—considered key to ensuring reactor safety. But after receiving whistle-blower information in early 2023, the NRA suspended its safety review of Hamaoka at the end of that year.
The fallout from this scandal adds uncertainty to Japan’s cautious nuclear restart program, especially given Hamaoka’s strategic importance and vulnerability to future seismic events. Chubu Electric’s move to replace its top leadership and withdraw the restart applications reflects efforts to address the serious compliance breaches and restore public trust in the wake of the data manipulation.