Temelín in Czechia disconnects its first unit, faces two-month outage and fuel replacement

The Temelín Nuclear Power Plant disconnected its first unit from the transmission grid shortly after 21:00 today. It will be left to cool over the weekend. The planned outage is for the replacement of part of the fuel and various investment projects. It will last around two months, plant spokesperson Marek Sviták told the Czech News Agency (ČTK) today.

"Over the weekend, the plant’s systems will gradually cool down. For example, in the primary circuit we will lower the water temperature by around 300 degrees. We will start opening the reactor once it has cooled, on Monday. Opening the reactor will take around four days," Sviták said.

Of the 163 fuel assemblies, 54 will be replaced, six more than last year. This will allow the unit to operate for two months longer, or 14 months, and the first unit will switch to a longer fuel cycle, the spokesperson added.

During the approximately two-month outage, energy workers plan to carry out 16,000 different tasks, including checks on the safety systems and turbine. They also plan to complete 70 investment projects focused on modernisation and further strengthening the plant’s safety. These include modernising safety valves in the technical water system and replacing one of the key fire-water tanks. The modernisation of the plant’s control system, which began in 2022, will enter its final phase. Around a thousand people, including contractors, will take part in the outage.

This will be the only planned fuel-reloading outage this year. The second unit, which switched to a longer fuel cycle last year, will be taken offline in February next year.