Investigation to Be Conducted into Emergency Diesel Generator Failure at Unit 6 of Japan's Kashiwazaki-Kariwa Nuclear Power Plant

Tokyo Electric Power Company announced that it will investigate the failure of the emergency diesel generator at Unit 6 of the Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture, Japan. The unit was restarted after 14 years of shutdown and resumed commercial operation in April this year. According to Tokyo Electric Power Company, in July this year, workers discovered that water had mixed into the lubricating oil of the emergency diesel generator at Unit 6. Subsequent inspections confirmed that there was a water leak in the cylinder head, a component of the generator engine. The company therefore determined that the unit currently does not meet the operational safety specification requirements. Tokyo Electric Power Company stated that it plans to complete the relevant repair work by September 19. If the repair cannot be completed by then, the cause of the failure will be further investigated, and measures may include shutting down the reactor for inspection.

2026-09-11

Another access control irregularity at Kashiwazaki-Kariwa Nuclear Power Station: exit gate fails to intercept unauthorized passage

Tokyo Electric Power Company (TEPCO) announced on August 7 that an irregularity related to access control occurred at the Kashiwazaki-Kariwa Nuclear Power Station. An operator improperly used his own ID card to allow a colleague who had left his ID card in the central control room to pass through the gate and exit. TEPCO stated that the access control system failed to display an error message at the time and was unable to prevent this unauthorized passage. According to disclosed information, the incident occurred during the exit process and involves management matters related to nuclear material protection. TEPCO has not yet publicly disclosed the specific date of the incident, the identities of the personnel involved, the detailed reasons why the system failed to trigger an alarm, or subsequent disciplinary actions and preventive measures. Kashiwazaki-Kariwa...

2026-08-08

Rising Seawater Temperatures Prompt New Nuclear Safety Rules: TEPCO Sets Temporary Shutdown Criteria for Kashiwazaki-Kariwa Plant

Tokyo Electric Power Company Holdings announced on August 7 that it has established a set of self-determined criteria for evaluating whether to temporarily halt nuclear reactor operations at the Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture, in response to rising seawater temperatures in the surrounding area. These criteria are not mandatory requirements directly imposed by external regulatory authorities, but rather proactive measures voluntarily implemented by TEPCO based on safe operational needs. According to the conditions announced by TEPCO, the company will consider temporarily shutting down the relevant nuclear facilities when the 7-day average seawater temperature in the waters surrounding the plant exceeds 31 degrees Celsius, when water temperatures above 34 degrees Celsius are observed, or when water temperatures above 33 degrees Celsius persist for 12 hours. These numerical thresholds indicate that seawater temperature has been incorporated as a key variable in nuclear power plant operational risk management.

2026-08-08

IAEA Director General to Inspect Kashiwazaki-Kariwa Nuclear Power Plant

Preparations are in the final stages for IAEA Director General Rafael Grossi's first inspection of Tokyo Electric Power Company's Kashiwazaki-Kariwa Nuclear Power Plant, expected to take place on August 18. Grossi has previously stated that there are "no obstacles to a swift restart," signaling a positive attitude toward the plant's reactivation. This inspection suggests that discussions surrounding the restart may accelerate. However, it is worth noting that local residents still harbor concerns, adopting a cautiously optimistic outlook on future developments. This marks Grossi's first visit to the Kashiwazaki-Kariwa plant, making it a significant event. Against the backdrop of growing attention to nuclear safety, the IAEA's...

2026-08-06