Second unit at Czechia's Temelín nuclear power plant resumes generating electricity after five days

The second unit at the Temelín Nuclear Power Plant is generating electricity again. Bohdan Zronek, a ČEZ board member and director of its nuclear division, announced the news on the social network X. Energy workers disconnected the second unit from the grid on 2 August. The originally unplanned work was prompted by increased vibration in the largest Czech turbine-generator set, which was observed in July.

„The work went according to plan and mainly involved checking the turbine’s seating in its plain bearings. The work itself took a matter of hours, but the equipment first had to be cooled down and then heated to a temperature that allowed electricity generation to resume. The second unit is currently operating at approximately 90 percent capacity, and we expect it to reach 100 percent later today, although this will depend on the parameters we are monitoring,“ nuclear power plant spokesperson Petr Šuleř said this morning.

The turbine consists of one high-pressure and three low-pressure sections. Together with the turbogenerator, it is almost 60 metres long, the entire turbine-generator set weighs more than 2000 tonnes, and the circumferential speed of its longest blades exceeds twice the speed of sound. By comparison, the adjustment to the axial guide clearance was just 0.09 mm.

According to Zronek, energy workers took advantage of a period of increased renewable generation to briefly cool one of the two largest Czech generating units and adjust the turbine bearing clearance along its axis. The outage did not affect electricity supplies, as the power was replaced by other sources.

The Temelín plant has generated 8.9 TWh of electricity so far this year, compared with 16 TWh for the whole of last year. The plant will invest 4.1 billion crowns in modernisation this year.