On the 22^nd of February, 2015 at 02.53 a.m. two main pumps (main pump-2,4) of the South-Ukrainian NPP unit No.1 were switched off. According to the project algorithm, the unit was automatically unloaded from capacity of 830 MW to 336 MW.

After having eliminated the malfunction (replacement of pneumocephaly device at localizing armature), NPP personnel put into operation the main pump-2,4. As of 14.00 p.m. February 23, 2015 capacity of NPP unit was restored.

By preliminary estimate the event was rated as the event without safety significance – “below Scale/Level 0” according to INES scale. There were no remarks concerning operation of technological protection systems, locking, automatics and equipment.

A commission on malfunction investigation was created.

Radiation at the site of the South-Ukrainian NPP and neighboring area remains unchanged at the value of 12 mR/h, which is usual background radiation level for the NPP area.

Physical protection system operates in normal mode.