External power has been restored to Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) a day after it lost access to off-site electricity in the latest incident highlighting continued threats to nuclear safety and security during the current armed conflict in the country, Director General Rafael Mariano Grossi of the International Atomic Energy Agency (IAEA) said today.
Also today, Ukraine’s national nuclear operator Energoatom said it was “doing everything possible to restore the operation of nuclear generation as soon as possible”, after Ukraine’s three other operational nuclear power plants were also disconnected from the grid yesterday.
Energoatom added: “Start-up operations are being carried out at the power units of the Rivne, South Ukrainian and Khmelnytskyy nuclear power plants. During the day, if the power system is ready … these stations will be connected to the power grid”. Ukraine separately informed the IAEA that the three plants had been relying on diesel generators for back-up electricity while in shutdown mode.
Director General Grossi noted that Ukraine’s nuclear industry yesterday had experienced the most extensive loss of off-site power since the conflict began nine months ago, saying this further underlined the need for stepped-up action to protect the plants and prevent the danger of a serious nuclear accident.
“The complete and simultaneous loss of off-site power for Ukraine’s nuclear power plants shows that the situation for nuclear safety and security in the country is become increasingly precarious, challenging and potentially dangerous. It is the first time that all the plants suffer a loss of external power at the same time. This would have been completely unimaginable before this tragic war. It is extremely concerning. All military action threatening the safety and security of Ukraine’s nuclear facilities must stop immediately,” Director General Grossi said.
At the ZNPP, the IAEA team of experts said the plant’s emergency diesel generators – eight of which had been operating since the loss of off-site power around 3:30pm yesterday – were switched off shortly before 9am this morning, after the plant’s access to both its main 750 kilovolt (kV) and back-up 330 kV lines was re-established.
Four of the reactor units remain in cold shutdown, while the two other units have been returned to hot shutdown again – enabling them to provide steam to the plant and heat to the nearby city of Enerhodar – after being cooled down following yesterday’s power loss. Enerhodar – where many plant workers live – is also receiving electricity again. The ZNPP has lost access to external electricity several times in recent months, for example in early November when it took two days to restore off-site power.
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 and 10 days or more in the case of the ZNPP. Four trucks with diesel fuel have arrived at the site to refill the tanks, the IAEA team reported today.
The need for secure off-site power supply from the grid for all nuclear sites is one of the seven indispensable pillars for ensuring nuclear safety and security during an armed conflict that the Director General outlined early during the conflict.
The IAEA team of experts also reported that repair work following the weekend shelling at the ZNPP site is continuing.