Apr 15, 2021 A series of security missteps at Tokyo Electric Power Co. Holdings Inc.’s Kashiwazaki-Kariwa nuclear plant should serve as a wake-up call for operators over the importance of addressing a potential terrorism threat immediately after any breach is confirmed, a top expert in the field has said. The Nuclear Regulation Authority on Wednesday effectively banned Tepco from restarting the plant in Niigata Prefecture after it was revealed that the facility had been susceptible to security breaches at 15 locations, and that 10 of them had been left unattended for more than a month. The regulator also found that a Tepco staffer had got past a security guard last September using a colleague’s ID card, and gained entry to the plant’s central control room, after the employee realized his own ID card was missing.