Fourth unit at Czechia's Dukovany plant back online after repairs

The fourth unit at the Dukovany Nuclear Power Plant is once again supplying electricity. It was disconnected from the grid on 13 March for repairs and an inspection of two valves in the plant’s non-nuclear section. Electricity supplies were restored today at 19:23 after the turbine was connected. Plant spokesperson Jiří Bezděk told CTK. From Friday until today, two of Dukovany’s four units were not generating electricity, as the planned outage of unit three began. This outage is expected to end in early June.

The planned outage of Dukovany’s fourth unit ended on 6 March. The need to repair two valves in the plant’s non-nuclear section became apparent during final tests after the unit was restarted following the outage, the spokesperson said.

The fission chain reaction in the fourth unit was restarted on Saturday. Its electrical output is expected to rise to 500 megawatt-hours (MWh) by Tuesday morning, the level it was at before the outage. After a series of further checks, the fourth unit is expected to reach a new, higher output of 512 MWh by the end of this week. The other three Dukovany units have been operating at the same higher output since last year.

Dukovany’s third unit was shut down as planned on Friday for regular equipment inspections and the replacement of some of its fuel with fresh fuel. It has not supplied electricity to the distribution grid since 18:53 on Friday. Over the weekend, energy workers cooled the unit, and today they began inspecting and testing its equipment. They will also carry out 60 investment projects on the unit. Key tasks include an eight-year inspection of the reactor, plant director Roman Havlín said.

Czechia has six nuclear units at two power plants. Last year, Dukovany supplied 14.7 terawatt-hours (TWh) of electricity to the transmission grid, while Temelín generated 15 TWh.

This year marks 40 years since Dukovany’s first unit began operating; it entered trial operation on 3 May 1985. All four Dukovany units have been in operation since July 1987. Last year, the government decided to build two more reactors at Dukovany. They are to be built by South Korea’s KHNP, with ČEZ now negotiating a final contract with the company. The first of the new reactors is expected to be completed in 2036.