Zaporizhzhia NPP Entirely De-energised

It was necessary to resort to emergency measures at the station.

The Zaporizhzhia NPP lost power during the night on Thursday, August 10. The station had to switch to the only available reserve line.

This is reported by the Ukrainian "Energoatom".

"The temporarily occupied Zaporizhzhia nuclear power plant lost power from the main external 750 kV power line during the night of August 10. After that, ZNPP had to switch to the only available 330 kV reserve line, the disconnection of which is fraught with the loss of external power (Bleakout)."

The Threat

As noted in Energoatom, in this case the main threat to nuclear and radiation safety is the stay of the 4th power unit of the Zaporizhzhia NPP in the state of "hot shutdown", which the occupants are operating in violation of the conditions of the licence for operation of NPP reactor units of the Ukrainian regulator (Gosatomregulirovanie).

As Taras Tkach, acting executive director of state-owned enterprise Energoatom, noted, in case of complete loss of external power supply, the plant's main circulation pumps will be switched off and the power unit will switch to the "natural circulation" mode.

"In this case, it is urgent to 'cool it down' in the absence of cooling pumps. Such a mode is hard for the reactor unit, its duration is limited by the project, and it can lead to failure of the main equipment of the power unit," he said.

Situation at Zaporizhzhia NPP

The Zaporizhzhia NPP has been occupied by Russian troops since the beginning of Russia's large-scale invasion of Ukraine. The Russians not only violate the operating regime of the plant, but also use its storage facilities to store equipment and manpower. The station has already been disconnected from Ukraine's energy system several times during the period of its occupation.

In particular, in early July, it was possible to connect the Zaporizhzhia NPP to the only available backup power line for the first time in four months. At the same time, the situation at the plant became more complicated after the Kakhovka HPP, which provided water for the plant's coolers, was blown up. It was reported on August 7 that there was enough water for ZNPP's coolers.