Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) was reconnected to its only remaining main 750 kilovolt (kV) power line on 10 August at approximately 19:00 local time after it had been disconnected at 16:13. It was the second outage of this power line on that day.
The IAEA team on site were informed that the disconnection occurred 5.5 km from the open switchyard on the southern bank of the river due to the activation of an overcurrent protection system.
During the outage, ZNPP relied on a single remaining 330 kV power line for the external electricity needed for reactor cooling and other essential nuclear safety and security functions. There was no loss of off-site power and no need to use the emergency diesel generators.
The plant’s external power situation remains highly vulnerable, underlining the precarious nuclear safety and security situation at the site.
As reported yesterday, ZNPP has started transferring reactor unit 4 to cold shutdown following the detection of a water leak at one of its four steam generators located in the containment of unit 4. Previously the unit was in hot shutdown to generate steam for various nuclear safety purposes.
Unit 6 is now being heated to hot shutdown state to continue steam generation. As the unit is not yet in hot shutdown state, there is currently no steam being generated at ZNPP.
The IAEA continues to strongly encourage the installation of an external source of process steam, which, from a nuclear safety perspective, would provide the safest longer-term solution for the steam needs at the site.
The other units at ZNPP remain in cold shutdown. As previously reported, the Ukraine national regulator – SNRIU – has issued regulatory orders to limit the operation of all six units to a cold shutdown state.