Japanese nuclear plant operator fabricated seismic risk data

In a startling development, Japan's Nuclear Regulation Authority (NRA) has announced the suspension of the relicensing process for two reactors at the Hamaoka nuclear plant. This decision comes in the wake of serious allegations that the plant's operator, Chubu Electric Power Co., falsified seismic hazard data. This revelation is particularly alarming as the Hamaoka facility is situated along the coast, near an active subduction fault, much like the infamous Fukushima Daiichi plant, which suffered a catastrophic meltdown following a major earthquake and tsunami in 2011. The NRA's investigation was reportedly triggered by a whistleblower's tip-off in February of the previous year, but it wasn't until this week that the details became public, leading to the suspension of a crucial evaluation process that could have set the stage for a reactor restart. Following the NRA's announcement, Chubu Electric released a statement outlining how it manipulated seismic safety assessments. According to their English translation, the operator utilized data from smaller earthquakes to scale up ground motion evaluations inaccurately. Typically, the established method involves generating a variety of 20 different upscaled earthquake motions to identify the one that best reflects the average risk. However, the company admitted that since 2018, it has been selectively choosing one scenario from a larger set while curating another 19 to ensure that the average appeared less risky than it truly is. While the company did not elaborate on the implications of this flawed methodology on overall risk assessments, it raises significant concerns about the actual safety of the Hamaoka plant and its preparedness for seismic events. As Japan continues to navigate the complexities of its nuclear energy policy in the post-Fukushima era, this incident underscores the critical need for transparency and integrity in safety evaluations.