Ukraine's Khmelnytskyy Nuclear Power Plant (KhNPP) lost all access to the electricity grid yesterday due to military attacks in the country, forcing it to temporarily rely on diesel generators for back-up power, Director General Rafael Mariano Grossi of the International Atomic Energy Agency (IAEA) said today, citing information he had received from Ukrainian authorities.
The KhNPP’s grid connection was completely lost at 18:35 local time on 15 November, after the site’s four operating power lines were progressively lost over a two-and-a-half-hour period because of missile attacks on the country’s energy infrastructure, Ukraine told the IAEA. During this period, the plant’s two reactors were shut down, halting their delivery of electricity to households, factories and others.
More than nine hours later – at 03:45 this morning – the plant regained off-site electricity through two 330 kilovolt (kV) back-up power lines, and the diesel generators were stopped. One of those lines was again lost about an hour later and only restored at 11:25. The two reactor units remain in shutdown mode.
Another nuclear power plant also located in western Ukraine – Rivne – lost the connection to one of its 750 kV power lines yesterday afternoon. As a result, the plant reduced its power output, and one of its four units was automatically disconnected. At 04:00 today, the plant increased the power of one of its other units to continue supplying electricity to the Ukrainian network
While Ukraine’s largest nuclear power plant – Zaporizhzhya – has lost off-site power several times during the current military conflict in the country, yesterday’s events underlined the fragile nuclear safety and security situation also at its other nuclear facilities. Ukraine has 15 reactors at four nuclear power plants, as well as the Chornobyl site.
“This was a very concerning development. It shows the potential nuclear safety and security risks facing all of Ukraine’s nuclear facilities during this terrible war, not just the Zaporizhzhya Nuclear Power Plant. While off-site power is now back at the Khmelnytskyy Nuclear Power Plant, yesterday’s power loss clearly demonstrates that the nuclear safety and security situation in Ukraine can suddenly take a turn for the worse, increasing the risk of a nuclear emergency,” Director General Grossi said.
Reactors need power for cooling and other essential nuclear safety and security functions also when they are in shutdown and do not produce electricity anymore. In the case of an external power loss, they have emergency diesel generators that can provide back-up electricity for a limited period of time, usually at least for several days.
The power loss at the KhNPP came just a day after the IAEA announced it would in the coming weeks send nuclear safety and security missions to this plant, Rivne and the South Ukraine nuclear power plant as well as to Chornobyl. The missions are being organized at the request of Ukraine.
“We will be at these nuclear power plants in the near future as part of our steadfast assistance to Ukraine in its efforts to maintain nuclear safety and security and prevent a nuclear accident during the conflict,” Director General Grossi said.
The IAEA already has a team of experts continuously present at the ZNPP.