Chubu Electric Power President Kingo Hayashi said Monday that the company might have cherry-picked earthquake data that caused authorities to screen safety standards at the Hamaoka nuclear power plant in Shizuoka Prefecture based on weaker quake projections.
As such, reactors at the Hamaoka plant are unlikely to be restarted anytime soon. Reactors No. 3 and No. 4 had been under safety screening by the Nuclear Regulation Authority (NRA), a nuclear watchdog, and in response to this issue, the process has been suspended since last month.
At a news conference at the company¡¯s headquarters in the city of Nagoya, Hayashi revealed that quake data provided to the NRA was not calculated as it was supposed to have been.
Hayashi said that some data used to calculate the plant¡¯s maximum seismic motion may have been handled inappropriately to meet the safe standards drafted after a tsunami triggered by the 2011 Great East Japan Earthquake knocked out the electricity at the Fukushima No. 1 nuclear power plant and caused a triple meltdown.
The company will establish an independent panel to investigate the incident, he said.
¡°There is a risk that this could have had a serious impact on the Nuclear Regulation Authority¡¯s review,¡± Hayashi said, apologizing for the potential mishandling. ¡°It undermines trust in our operations, and could strike at the very foundation of our business.¡±
According to Chubu Electric, at a regulatory review meeting in January 2019, the company had told the NRA that it will calculate a set of 20 seismic ground motion estimates based on different conditions to serve as data for calculating a representative figure for the safety standards at the Hamaoka nuclear power plant.
However, prior to 2018, instead of preparing a single set consisting of 20 simulations of seismic motion, the company had been creating multiple sets, and selected one of them to submit to the NRA.
At some point after 2018, the company selected one simulation that was not closest to the average, and selected 19 others for the set, so that it would appear like that would be the average.
Tetsuya Toyoda, head of the company¡¯s nuclear power department, said he believed there had likely been intent ¡°to make the seismic motion appear smaller.¡±
The Ministry of Economy, Trade and Industry has requested Chubu Electric to report by April 6 in detail on what caused the inappropriate practices and to propose measures to prevent recurrence in the future.
The news comes mere months after another scandal regarding safety measures at the same plant. In November, Chubu Electric¡¯s then-vice president and other executives resigned after it came to light that the utility had engaged in inappropriate procedures such as not signing official contracts with some of the contractors for safety construction projects.
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