Ukraine and the International Atomic Energy Agency (IAEA) said two power lines connecting the Zaporizhzhya nuclear plant to the country’s electricity grid were cut overnight, again highlighting the risk of an accident at the plant.
The IAEA confirmed in a statement on December 2 that the plant in southern Ukraine lost offsite power overnight and temporarily relied on emergency diesel generators.
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The plant, which stopped supplying electricity to the Ukraine's grid in September 2022, has been rocked by repeated shelling and drone attacks since Russia launched its full-scale invasion of Ukraine in February 2022.
Although its six reactors have been shut down, it still needs power to operate cooling systems and other safety features.
The Zaporizhzhya nuclear power plant "lost the connection to both of its external power lines," IAEA Director-General Rafael Grossi said in a statement, adding that this is the eighth time since the start of the war that the plant, Europe’s largest, suffered a complete offsite power outage.
The IAEA team at the site reported that the connection to its sole back-up 330 kilovolt power line was cut around 10:26 p.m. local time on December 1 due to "an external grid fault," Grossi said. This was followed around five hours later by the loss of the plant’s sole 750 kilovolt line -- its main supplier of external electricity.
The cause appeared to be in the outside grid far away from the plant, Grossi said.
"The most recent external power outage is yet another reminder about the precarious nuclear safety and security situation at the plant, which can be affected by events far away from the site itself," Grossi said.
The safety situation at the plant has been a source of concern since it was captured by Russian forces last year, and the two sides have accused each other of compromising its safety.
SEE ALSO: West 'Too Cautious About Giving Ukraine Weapons That Could Strike Into Russia,' Says Former NATO CommanderEnerhoatom, Ukraine's nuclear energy operator, said in its statement that due to the outage the plant switched to 20 diesel generators.
The IAEA said these generators automatically started operating and the staff at the plant, which includes a team of IAEA experts, then reduced the number in operation to eight, which is enough to ensure that the plant’s reactors have enough power for cooling.
The affected 750 kilovolt power line was reconnected shortly after 8 a.m. local time on December 1, and the eight diesel generators were being gradually shut down.
Enerhoatom said the plant was on "the verge of a nuclear and radiation accident" before off-site power was restored.
"The situation was actually saved by the prompt actions of Ukrainian specialists who restored power supply to the plant from the Ukrainian power grid," it said.
It was not possible to verify Ukraine's claims.