Two Chubu Electric leaders resign after falsified quake data; Hamaoka restart plans dropped

Two senior executives at Chubu Electric Power stepped down on Monday after the operator admitted it had submitted earthquake data that understated seismic risks, and the firm said it would abandon plans to restart two reactors at its Hamaoka nuclear plant.

Resignations and halted restart plans

Chubu Electric said President Kingo Hayashi and Chairman Satoru Katsuno would be replaced following revelations of data tampering linked to seismic risk estimates for the Hamaoka plant. The company also announced it would withdraw applications to restart two reactors at Hamaoka.

Executives’ statements and internal findings

At a news conference, President Kingo Hayashi said he felt “a heavy sense of responsibility and am deeply remorseful”. He added he felt “a profound sense of regret” that he had been unable to “foster an organisational culture that prioritises compliance and safety above all else.”

An independent panel released a 250-page report on Monday that said management’s “reprimand” over delays in the restart review had created pressure on staff and was “one of the factors contributing to the misconduct.”

Regulatory timeline and safety review

The estimate of maximum seismic ground motion is important for earthquake-resistant design of nuclear plants. In September 2023, the Nuclear Regulation Authority approved Chubu’s estimate of 1,200 gal for Hamaoka. In February last year the NRA received information about possible data fraud from a whistleblower, and the NRA suspended its safety review process for Hamaoka in late December.

Why the issue matters

The Hamaoka plant is located in Omaezaki in Shizuoka prefecture, an area near a seismic fault line where authorities have warned a massive Pacific earthquake could occur in coming years or decades. In 2024, the Japan Meteorological Agency issued its first special advisory for a possible “megaquake” in the Nankai Trough area before lifting it a week later.

Nationally, Japan has been moving to revive nuclear power more than a decade after the 2011 Fukushima meltdown. The source said the country aims to reduce its dependence on fossil fuels, achieve carbon neutrality by 2050 and meet growing energy needs from artificial intelligence. The world’s biggest nuclear plant, Kashiwazaki-Kariwa, restarted operations earlier this year.

Next steps

Chubu Electric’s withdrawal of restart applications and the leadership changes follow the independent panel’s findings and the regulator’s suspension of the review. The company and regulators will be expected to address the issues the report identified as contributing factors to the falsification of seismic data.