Temelín upgrades safety systems: hundreds of components to be replaced by 2029

The Temelín nuclear power plant in the České Budějovice region is continuing to modernise the controls of safety systems, including safety pumps and key shut-off valves. It is currently replacing components at Unit 2. By 2029, plant operators will replace 273 electrical power supply components. The aim is to ensure the plant’s long-term safety and operational capability, plant spokesperson Marek Sviták said.

ČEZ is working with system supplier Westinghouse and Czech control systems manufacturer ZAT on the upgrade. As a subcontractor, ZAT is producing the new power supplies. "The current replacement programme is focused exclusively on Unit 2. It is not merely about upgrading the equipment itself, but also about the spare-parts management strategy. The original power supplies, which remain fully functional, will not be decommissioned but used as a service reserve for Unit 1," said plant director Petr Měšťan.

The specialised components supplied by the Příbram-based company serve as protective filters and adapters for one of the plant’s most sensitive systems. Their main function is to reduce the standard 230-volt grid voltage to very low levels of between five and 24 volts. This converted and perfectly stable current, free from any fluctuations, then continuously powers the sensitive electronics monitoring unit safety.

The entire system, consisting mainly of processor units, control cards and fans, operates in an isolated environment, ensuring its cybersecurity. "Both hardware and software continue to evolve, but we use only fully proven technologies. We need systems that are prepared for long-term operation. This is therefore not just modernisation, but a systematic approach," said Bohdan Zronek, ČEZ board member and director of the Nuclear Energy division.

Since the beginning of the year, the Temelín power plant has generated 8.3 terawatt-hours of electricity. ČEZ will invest CZK 3.8 billion in modernising the plant this year, CZK 700 million more than last year.