Zaporizhzhia NPP Unit 5 to go into cold shutdown

On June 9, the State Nuclear Regulatory Inspectorate of Ukraine ordered Energoatom to put the last Zaporizhzhia NPP operating power unit, No.5, into a cold shutdown.

The State Nuclear Regulatory Inspectorate of Ukraine published the statement.

"Cold shutdown" is a nuclear reactor safe state when the reactor is shut down at low pressure and cooling water temperature. It is an intermediate reactor state between operation and fuel overload.

The decision was made because of the inability to eliminate violations of nuclear and radiation safety requirements at the temporarily occupied plant. 

"Given the loss of the main design source of splash pool feeding, it is necessary to immediately start transferring ZNPP Unit 5 to a cold shutdown state while the design mode of operation of the necessary cooling systems is still maintained," the statement says.

The reasons include the Kakhovka HPP explosion, the Zaporizhzhia NPP recurring shelling by Russians, and the emergency response system at the ZNPP site degradation.

The restriction on the operation of Zaporizhzhia NPP Unit 5 will remain in force until the identified violations are eliminated. The function of other ZNPP units 1, 2, 3, 4, and 6 is also restricted by the cold shutdown condition. 

It will be recalled that on May 22, due to shelling, the last high-voltage transmission line, Dniprovska, which supplied the temporarily occupied Zaporizhzhia NPP with power for its own needs, was disconnected at 5:26 a.m. This nuclear power plant is de-energised for the seventh time.