During the downtime, the reactor was refilled with fresh nuclear fuel, with regular maintenance and repairs being carried out.
Following a completion of scheduled maintenance which started on 11 April, Bulgarian sole nuclear power plant Kozloduy announced that its 1,000 MW unit 5 was successfully reconnected to network on 23 May.
Originally, NPP Kozloduy had six reactors, but four older 440 MW reactors were shut down in 2007 due to nuclear safety concern of the European Union. The plant currently operates two Soviet-built 1,000 MW reactors, unit 5 and unit 6 which were commissioned in 1987 and 1991 respectively.