Cooling continues at Czech Temelín plant as a cooler is set to be replaced

At the Temelín nuclear power plant, systems are being cooled down today following Wednesday’s unplanned disconnection of the second generating unit, so repairs can begin. Most likely, one of the four coolers in the generator’s internal cooling system will be replaced, nuclear communications manager Petr Šuleř told ČTK. Residents living near the plant have been informed about the repair. According to Temelín Mayor Josef Váca, it is a routine fault. He told ČTK.

“The systems are being cooled down, and we are waiting for conditions that will allow all the work to begin,” Šuleř told ČTK.

The inspection results should be available within about 24 hours, and one of the four coolers in the generator’s internal cooling system will probably be replaced. Šuleř said workers already have all the materials they need. “After the replacement itself, leak-tightness tests must be carried out. The timing of resynchronization with the grid will depend on the results. However, the work and subsequent leak-tightness checks should not take longer than the announced period of a few days,” Šuleř added.

The plant disconnected the second generating unit unexpectedly on Wednesday morning. Šuleř said local residents received a text message about the outage after 7:15. People registered with the information system for residents living near nuclear power plants received emails. Mayors of nearby municipalities were also given more detailed information.

Temelín Mayor Váca told ČTK that he had received the information and that it was a routine fault, unrelated to any risk of radioactivity. He added that he was not worried.

The current outage is the first unplanned one since 2019. The plant said on Wednesday that the fault was in its non-nuclear section. It is an operational issue that has no impact on the surrounding area or on customers; ČEZ will make up for the lost output using other energy sources. The work should take no more than a few days. It will not affect the primary circuit or the first generating unit, which is operating at 100 percent capacity.

The turbine-generator sets at Temelín are the largest in the Czech Republic. Each generating unit has one high-pressure and three low-pressure turbine sections, directly connected to an electric generator with a maximum output of 1125 megawatts. “They convert thermal energy into electricity and, through so-called extraction points, supply steam to heat exchangers,” Šuleř said previously. The Temelín plant has had a reliability rate of 99.5 percent in recent years, well above average compared with other energy sources, he added.

Temelín is the country’s largest electricity producer, supplying about a fifth of domestic consumption. It generated 16.1 terawatt-hours (TWh) of electricity last year and has produced 3.04 TWh so far this year.