All three units that were disconnected from the grid last week at the Kalinin nuclear power plant are now supplying electricity as normal, Russia's Rosenergoatom announced on 20 July. Kalinin units 1, 2 and 4 had lost connection with the network on 18 July after a transformer switch short circuited. The switchgear has since been repaired.
Units 1 and 2 shut down, while unit 4 was offline at reduced thermal power output. Kalinin unit 3 was unaffected and continued operating as usual. The plant is north-west of Moscow, in the Tver region.
"The fault was caused by a short circuit in the open switchgear of one of the transformers serving the plant, which led to the disconnection of two 750 kV power lines - Belozerskay and Experimental," Rosenergoatom said, adding that the fault was entirely unrelated to the plant's main equipment.
"Unit 2 reached the rated capacity of 1000 MW on 20 July and thus, at present, the operation of all three power units - disconnected from the network due to a short circuit that occurred on 18 July on the busbar of one of the station’s current transformers - has been restored," it said. On the same day unit 4 was connected to the network, following unit 1 on 19 July, it added.
The background radiation level at the plant and surrounding area remains unchanged, corresponds to the normal operation of the power units, and does not exceed the natural background value of 8-12 microsievert per hour, it said.
