The estimate of maximum seismic ground motion is important for the earthquake-resistant design of nuclear plants.
In September 2023, the NRA approved Chubu Electric’s estimate of 1,200 gal, a unit of acceleration used to measure the intensity of quakes.
But in February last year the NRA received information from a whistleblower that the utility “may have used data different from what was presented” to the nuclear watchdog, NRA official Keiichi Watanabe told AFP on Tuesday.
Since then, the watchdog has been conducting its own probe, he said.
The NRA suspended its safety review process for the Hamaoka plant in late December, and the issue “will be discussed in meetings open to the public”, the first of which will be held on Wednesday, he said.
The Hamaoka plant is located in Omaezaki, Shizuoka prefecture, near a seismic fault line where a massive Pacific earthquake is expected to occur in the coming years or decades.
In 2024, the Japan Meteorological Agency issued its first special advisory for a possible “megaquake” in the area, known as the Nankai Trough, before lifting it a week later.
The government has said a quake in the 800km undersea trench and subsequent tsunami could kill as many as 298,000 people and cause up to US$2 trillion in damages.
Chubu Electric said it had set up a panel of lawyers to look into the matter.
Source: CNA
