Manipulated data: Japanese authority stops nuclear power plant reactivation

In Japan, nuclear power plants that were shut down after the Fukushima disaster are currently being reactivated. However, two reactor units at the Hamaoka power plant will not be put into operation for now due to allegations of falsification.

Japan's nuclear regulatory authority has suspended the safety assessment of reactors 3 and 4 at the Hamaoka nuclear power plant. The authority accuses the operator, Chubu Electric Power Company, of falsifying data regarding earthquake risk, as reported by the US news agency AP.

The Hamaoka power plant is located on the east coast of the main island of Honshu, roughly halfway between Tokyo and Osaka. Off this coast runs the Nankai Trough, which marks the boundary between two tectonic plates. Very severe earthquakes that trigger large tsunamis occur here every 100 to 200 years. The last of these Nankai Megathrust earthquakes took place at the end of 1946.

Note from a Whistleblower

After the Fukushima disaster in 2011, many nuclear power plants in Japan were shut down. In 2014 and 2015, Chubu Electric Power applied for safety inspections to restart reactors 3 and 4 at Hamaoka. For this purpose, the company submitted data on seismic risks to the regulatory authority. In February 2025, the authority received a tip from a whistleblower that Chubu had been submitting manipulated data for years, downplaying the earthquake risk.

The nuclear regulatory authority subsequently launched an investigation. However, the matter only became known now when the safety assessment procedure was suspended. Chubu has admitted that the methods used deviated from the standard procedure for assessing such risks, and possibly intentionally.

The safety assessment is a prerequisite for a new operating license. Whether and when the procedure will be resumed is unclear. This also puts the commissioning of Hamaoka 3 and 4 in question.

After Fukushima, well over 50 of Japan's nuclear power plants were taken offline. However, the government is now increasingly relying on nuclear power again. Reasons include climate protection and the impact of the Ukraine war on the energy sector. In a few days, Kashiwazaki-Kariwa, the world's largest nuclear power plant, among others, is scheduled to go back online. It belongs to the energy provider Tepco, which also operated Fukushima.

(wpl)