Ukrainian Energy Minister Herman Halushchenko has appealed to the International Atomic Energy Agency (IAEA) about the loss of the main power line supplying electricity to the Zaporizhzhya nuclear power plant in southern Ukraine.
Halushchenko said on Ukrainian television on August 10 that the nuclear plant is currently being supplied with power from a backup line.
"This is the only external power line left. And such a situation is one step away from the blackout of the Zaporizhzhya nuclear power plant -- that is, the final loss of external power supply," Halushchenko said.
In the event of a blackout, diesel generators would be connected to meet the needs of the station, but they may be damaged by Russian shelling, which would stop the cooling of the station and set off a nuclear meltdown, Halushchenko said.
Ukraine's nuclear authority, Enerhoatom, warned earlier on August 10 that the Russian-occupied nuclear plant is on the verge of a blackout because power was cut from the main high-voltage line.
An IAEA news release on August 10 said the main power line had been disconnected twice during the day and "remains disconnected."
The statement confirmed that the disconnections mean that the Zaporizhzhya plant has had to rely on its only remaining off-site backup power line to supply the electricity needed for safety functions such as pumping cooling water for the plant.
The statement said there had been no total loss of off-site power to the site and there was no need to use the emergency diesel generators.
But IAEA Director-General Rafael Grossi warned in the statement that the "repeated power line cuts underline the continuing precarious nuclear safety and security situation at the plant."
Russian troops occupied the nuclear plant near the start of Russia's full-scale invasion of Ukraine in February 2022, and intense fighting and shelling continues in nearby areas.
The IAEA's news release on August 10 also said the nuclear power plant had started to transfer reactor Unit 4 from hot shutdown to cold shutdown following detection of a water leak in one of its steam generators.
Unit 4 will be placed into cold shutdown to determine the cause of the water leak and to conduct maintenance to repair the affected steam generator, Grossi said. There was no radiological release to the environment as a result of the leak, he added.
At the same time, over the next three days, the plant will move Unit 6 to hot shutdown to continue steam production on site.
Unit 6 has been in cold shutdown since April 21 to enable inspection and maintenance of the safety systems.
Steam production from one reactor unit in hot shutdown is necessary for various safety purposes including the processing of liquid radioactive waste collected in storage tanks.
The IAEA team on site will closely monitor the operations for the transition of the shutdown states of Units 4 and 6. The other units at the plant remain in cold shutdown.