Chubu Electric Power has withdrawn its applications to restart two nuclear reactors at its Hamaoka power plant following revelations of data manipulation in seismic safety submissions. The move, announced on September 14, 2026, comes after an independent committee concluded that pressure from senior management led engineers to alter earthquake data submitted to Japan’s nuclear regulator, casting serious doubts on the reliability of the utility’s safety assessments.
The decision effectively halts a process that had been ongoing for more than a decade, delaying the restart of the two reactors and representing a significant setback for Japan’s efforts to revive nuclear power in the wake of the 2011 Fukushima Daiichi disaster. Chubu Electric’s chief executive and chair resigned amid the fallout. The company stated that maintaining the existing restart applications was no longer appropriate due to the "serious doubts" raised about the application documents and how the issues were handled during the review process.
The independent investigation found that Chubu Electric’s engineers deliberately manipulated seismic data used to evaluate how the plant would respond to potential earthquakes. Specifically, they produced altered data sets that underestimated the strength of seismic waves, thereby influencing the safety review in the company’s favor. The committee described the utility’s culture as “extremely unusual,” with engineers acting according to their “own logic” rather than adhering to established nuclear safety regulations. The report noted that those involved appeared unaware that their actions were problematic.
Initial concerns surfaced in 2021 when a whistleblower sent an internal email revealing that weaker seismic waves had been selected three years earlier. However, the company’s initial internal inquiry, led by the department implicated in the misconduct, reported no compliance violations. It was only after the independent committee’s formation in January 2026 that the full extent of the data manipulation came to light. While the committee identified management pressure as a factor in the misconduct, it found no evidence of direct orders from top executives to alter data for regulatory approval.
Japan's nuclear industry has faced ongoing challenges since the Fukushima disaster forced the shutdown of all 54 commercial reactors and exposed systemic issues within the country’s nuclear establishment. Critics have long highlighted a tightly-knit “nuclear village” of utilities, regulators, and government officials that hindered rigorous safety oversight. Since then, Japan has gradually restarted 15 reactors and aims to increase nuclear power’s share of electricity generation from 8.5 percent currently to about 20 percent by 2040—still below pre-Fukushima levels of roughly 30 percent.
The Hamaoka reactors, operated by Japan's third-largest utility, were considered key to the country’s nuclear revival strategy. Analysts now estimate that their restart will be delayed by at least three years, potentially pushing back reactivation dates to 2032 and 2035. The setback complicates Prime Minister Sanae Takaichi’s goal to reduce energy costs and supply reliable power to the nation’s AI data centers and manufacturing sector, both of which rely heavily on stable electricity supplies.
Chubu Electric’s withdrawal underscores the ongoing challenges facing Japan as it seeks to restore confidence in nuclear safety amid persistent public and regulatory scrutiny.