The Czech State Office for Nuclear Safety (SÚJB – Státní úřad pro jadernou bezpečnost) has authorised state power company ČEZ to use new nuclear fuel from Westinghouse at the Temelín NPP. Workers plan to introduce the new fuel assemblies into the unit 1 VVER-1000 reactor during the planned shutdown at the end of this year. The permit was issued after a several-year process of preparation, testing and security analysis.
“This is another important step in strengthening the energy security of the Czech Republic and diversifying nuclear fuel suppliers.” said ČEZ Board Chairman & CEO Daniel Beneš. “In addition, we also hold strategic reserves in both of our nuclear power plants.”
ČEZ has been working for a long time to diversify its fuel suppliers. In addition to Westinghouse, which has also delivered the first assemblies for the Dukovany NPP (with VVER-440 reactors), it also has a contract with the French company Framatome for Temelín.
Westinghouse fuel is not new to Temelín. Westinghouse first delivered nuclear fuel to the Temelín NPP in 2000. The initial supply arrangement came to an end around 2009–2010 due to technical and operational problems with fuel assemblies which experienced bowing and structural growth inside the reactor. Control rods failed to fully insert properly during operations and micro-leaks compromised fuel integrity.
Because of these safety and reliability concerns, ČEZ held a tender in 2006 won by Russia’s TVEL. ČEZ phased out the remaining Westinghouse fuel, completely switching back to TVEL by 2010. Now, following changing geopolitical landscapes, ČEZ has returned to Westinghouse whose VVER-1000 fuel has since been redesigned.
The extensive approval process included a detailed safety evaluation. For almost two years, experts evaluated the behaviour of the fuel during normal operation, in terms of safety aspects, its compatibility with the reactor, as well as the method of handling and storage. A batch of 30 of the new fuel assemblies (specifically the Robust Westinghouse Fuel Assembly design, or RWFA-T) arrived at Temelín in May 2025. The following month a batch of NOVA E-6 design assemblies were delivered for Dukovany. These have undergone a series of checks to verify their technical condition and compliance with safety requirements.
“We are planning the first introduction of new fuel this year during the planned shutdown of the Temelín unit 1, said Bohdan Zronek ČEZ Board member and Director of the Nuclear Energy Division. “And at the same time, we will continue with preparations for licensing the Dukovany fuel assemblies.”
In recent years, the ČEZ Group has gradually switched to longer fuel campaigns using TVEL fuel. In Dukovany, a sixteen-month cycle is the standard as of 2024. Temelín will complete the transition to an 18-month fuel campaign this year. Longer operation between shutdowns increases electricity production and contributes to higher efficiency of operation. The Temelín and Dukovany plants account for approximately 40 % of Czech electricity consumption.
