TEPCO Confirms Operator at Kashiwazaki-Kariwa Used Colleague's ID Card After System Failed to Block

TEPCO disclosed an access-control violation at its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture. An operator, upon leaving the central control room, left a personal ID card inside and then used a colleague's ID card, belonging to a co-worker who had already departed, to pass through the gate. The incident occurred on February 18, 2026, and was confirmed through TEPCO before August 10.

According to TEPCO, the operator was on duty in the central control room for Units 6 and 7 and discovered the ID card had been left inside when preparing to exit. A colleague who had already left used their own ID card to help the operator pass through the gate. By design, if a person who has already passed through the gate attempts to perform an exit operation again, the system should display an error and block passage, but the gate did not show an error message.

TEPCO said such an action was improper but could not be blocked by the system. The cause was aging equipment in the management system, which had previously presented similar fault risks. The situation reflects vulnerabilities in the plant's access-control procedures, and TEPCO has provided details of the incident.