External power had been restored to the Zaporizhzhia Nuclear Power Plant by Sunday night after repeated shelling caused an outage that lasted nearly two days, the chief of the United Nations’ nuclear watchdog, Rafael Mariano Grossi, said in a statement.
Mr. Grossi, the International Atomic Energy Agency’s managing director, is planning to visit Russia early this week for talks about establishing a safety zone around the plant in southern Ukraine, a goal that has received renewed urgency after a series of attacks in the area the past week. Mr. Grossi was in Kyiv, Ukraine’s capital, on Thursday to begin the negotiations.
Early Saturday, Russian shelling caused the plant to lose access to external power, forcing it to rely on diesel generators to power safety equipment used to cool its reactors, according to Ukrainian officials. Russia’s Ministry of Defense blamed Ukrainian forces for the shelling, saying in a statement on Telegram that Ukrainian rockets had hit near the industrial zone and knocked out the power supply.
Mr. Grossi said in the statement that there has been shelling “almost every day now” around the plant, including “where the plant workers and their families live.”
The plant has been disconnected from external power at least twice before, and the availability of fuel to power the emergency generators has long been a concern. Even with all the reactors offline in what is known as a cold shut down, essential equipment dedicated to cooling spent fuel rods needs a constant source of power.
Once power was restored on Sunday, Mr. Grossi said in a Twitter post that it was a “temporary relief in a still untenable situation.”
The Zaporizhzhia nuclear plant, the largest in Europe, has been at the center of active fighting since Russian forces seized it in March, raising concerns about a potential nuclear accident. Russian forces control the plant, but it is still being run by Ukrainian operators.
The Kremlin announced last week that it would take over operational control of the facility, introducing even more uncertainty. The I.A.E.A. said on Thursday that it did not recognize Russia’s claims to the plant.
