Czechia's Temelín nuclear plant disconnects first unit, technicians to adjust turbine bearing

The Temelín nuclear power plant disconnected its first unit early this morning. Technicians will now adjust the turbine bearing arrangement, as they previously did on the turbine at the second unit. In July, vibration appeared there, forcing energy workers to temporarily reduce its output. Plant spokesperson Marek Sviták told the Czech News Agency (ČTK).

„First, the equipment will have to cool down so that work can be carried out on it. In practice, this means we have to lower its temperature by approximately 200 degrees Celsius,“ he said.

„The adjustment to the turbine's sliding bearing is then scheduled to take several hours. Once it is complete, we will have to heat the unit back up during start-up. We hope to complete the work by the start of the school year,“ the spokesperson added.

„The adjustment on the second unit proved successful, so we do not want to wait until the first unit's outage next year. Instead, we will take advantage of the period when renewable generation is typically higher in summer. It is not urgent, but it makes sense for us both operationally and economically,“ Bohdan Zronek, a member of the board and head of ČEZ's nuclear energy division, which operates the Temelín plant, said earlier.

The turbine-generator sets at Temelín are the largest equipment of their kind in the Czech Republic. One high-pressure section, three low-pressure sections and the generator together measure 65 metres in length. Once heated to operating temperature, they expand by approximately three centimetres, while having to remain completely sealed. This is why these machines are designed to allow axial movement. The weight of each set exceeds 2000 tonnes, and the peripheral speed of the longest blades is more than twice the speed of sound.

Since the beginning of the year, the Temelín power plant has generated 9.9 terawatt-hours (TWh) of electricity. It generated 16 TWh of electricity over the whole of last year.