One of the six reactors at Ukraine’s Zaporizhzhya Nuclear Power Plant lost power for about an hour and a half last week, causing an emergency diesel generator to kick in to provide electricity for cooling and other functions, the International Atomic Energy Agency said.
Plant personnel continue to investigate what caused the 90-minute power outage to reactor number 6 on Nov. 15, International Atomic Energy Agency (IAEA) Director General Rafael Mariano Grossi said in a Nov. 21 statement.
The plant is also switching the number 5 reactor unit to cold shutdown, in part to investigate why boron was detected in a cooling circuit. The plant will still have one of its six reactors in hot shutdown to produce steam and heating for the plant and nearby Ernohodar, the IAEA said Tuesday
IAEA personnel at the nuclear plant, Europe’s largest, are also gathering information to make an independent assessment of the event. The reactor is in cold shutdown, but still needs access to power, the agency said. None of the plant’s five other reactors lost power. Three of them are also in cold shutdown, while two are in hot shutdown to generate steam and heating.
“While this was not a total loss of off-site power, as we have seen seven times before during the conflict, it once again highlights the precarious nuclear safety and security situation at the Zaporizhzhya Nuclear Power Plant,” Grossi said. “The IAEA will continue to collect information so we can inform the international community about the situation at the plant.”
The day after the power outage, plant personnel informed the on-site IAEA team that part of the safety system of the same unit would undergo planned maintenance.
Power to the plant has been a major concern for the IAEA since Russia’s all-out invasion of Ukraine began in February 2022. The plant is still connected to the electricity grid by a single 750-kilovolt main power line – of which there were four before the conflict – and a single backup 330-kV line, down from six less than two years ago, the IAEA said.
Meanwhile, the IAEA team at the plant continue to hear explosions almost daily from combat on the front lines near the facility.
Still, the team was able for the first time to inspect all six main reactor control rooms at the plant in succession on the same day, providing an opportunity to gather information about staffing levels and to confirm the status of each reactor unit.
“This has been a positive development regarding access. I strongly encourage the plant to ensure that timely access and information sharing take place regularly,” Grossi said. “It will enhance our capability to report about the overall situation at the plant.”
Later this week, the IAEA team on the ground was scheduled to observe a planned emergency exercise at the plant.
“We look forward to observing the emergency response exercise at the Zaporizhzhya Nuclear Power Plant from both the temporary emergency control centre and in the field,” Grossi said. “Emergency exercises are very important for nuclear safety, especially in these times of heightened risk caused by the conflict.”
