Japan's nuclear power sector is facing renewed scrutiny following allegations that Chubu Electric Power Company may have underestimated earthquake risks at the Hamaoka Nuclear Power Plant in Shizuoka Prefecture. The controversy has prompted government intervention and raised questions about regulatory oversight, even as the Shimane Nuclear Plant continued operations during recent seismic activity. According to NHK, the Nuclear Regulation Authority (NRA) is considering requiring a complete redo of seismic safety assessments for the Hamaoka plant after discovering potential irregularities in how Chubu Electric calculated expected earthquake ground motion. The authority suspects the utility may have engaged in improper conduct during the審査 審査 (shinsa, safety review) process, deliberately underestimating the intensity of potential seismic shaking at the facility. The Hamaoka plant, located directly above the Nankai Trough—one of Japan's most significant earthquake zones—has been offline since 2011 following the Fukushima disaster. Chubu Electric has been seeking regulatory approval to restart operations, but these new allegations could significantly delay or derail those plans. The NRA's potential decision to restart the seismic review from scratch represents a serious setback for the utility's restart timeline. Chief Cabinet Secretary Kihara addressed the issue at a press conference, describing the alleged underestimation as something that "could shake public trust and should never happen," according to NHK. Kihara stated that the government expects Chubu Electric to conduct a thorough investigation into the matter, signaling that this issue has escalated beyond regulatory concern to become a matter of national policy significance. For foreign residents in Japan, particularly those living in central Japan near the Hamaoka facility, these developments highlight ongoing debates about nuclear safety in one of the world's most seismically active regions. The Hamaoka plant's location has long made it controversial—it sits approximately 200 kilometers southwest of Tokyo in an area where major earthquakes are statistically overdue. Meanwhile, recent seismic activity has tested Japan's operating nuclear facilities in real-time. According to NHK, when earthquakes struck on January 6, the Shimane Nuclear Power Plant's Unit 2 reactor—currently in operation after restarting—continued running because ground motion remained below automatic shutdown thresholds. Chugoku Electric Power Company, which operates the Shimane plant, reported no abnormalities at the facility. The Ikata Nuclear Power Plant in Ehime Prefecture also reported no issues following the same seismic events. These incidents demonstrate that Japan's nuclear facilities regularly experience earthquake activity, making accurate seismic risk assessment critical for public safety. The contrast between these two situations is instructive. While the Shimane plant operated safely through actual earthquake conditions, the Hamaoka controversy centers on whether safety reviews accurately reflect potential risks before restart approval is granted. This underscores the importance of the NRA's審査 審査 process in ensuring that nuclear facilities can withstand worst-case seismic scenarios. For expats, these developments serve as reminders of Japan's complex relationship with nuclear power. Following Fukushima, Japan temporarily shut down all nuclear reactors, and the restart process has been gradual and contentious. Each facility must pass rigorous safety reviews before resuming operations, though critics argue that political and economic pressures sometimes conflict with safety priorities. The government's strong response to the Hamaoka allegations suggests authorities are taking nuclear safety concerns seriously in the post-Fukushima era. However, the incident also reveals potential weaknesses in the oversight system if a major utility could allegedly manipulate safety data during the review process. As Japan continues balancing energy security needs with safety concerns, foreign residents should stay informed about nuclear facilities in their regions and understand emergency procedures. The Hamaoka situation will likely develop over coming months as investigations proceed and the NRA determines whether a complete審査 審査 restart is necessary.