Czech power utility CEZ says unit 2 of the Temelín NPP, during its current outage, is transitioning from a 12-month to an 18-month fuel cycle as part of a wider programme to increase efficiency and move towards a 60-year operating life.
Temelín has two VVER-1000 units that began operation in 2000 and 2002. The Dukovany NPP has four VVER-440 units. Together they generate 34% of the Czech Republic’s electricity.
During its shutdown, 163 fuel assemblies will be placed in unit 2, including 48 fresh assemblies, which is six more than previously. Extending the fuel cycle to 18 months will increase the efficiency of the plant, allowing it to operate for longer between shutdowns. “The fuel enrichment will be the same, but the assemblies will contain more absorbers to dampen their reactivity. This, combined with a higher number of fresh assemblies, ensures that the unit will be able to operate for longer,” explained Temelín Plant Director Jan Krumlov. “It's like throwing seven coal briquettes into a stove instead of five and closing the air a little, it will last longer. In our case, however, it is without emissions.”
"We are extending the fuel cycles to 16 months in Dukovany and 18 months in Temelín,” said Bohdan Zronek, director of CEZ's nuclear energy division. “This means a reduction in lifetime consumption and a contribution to production of almost 2 TWh a year on average. This of course requires very careful verification of all safety parameters."
Key projects include extending the fuel campaign, modernising control systems and preparing for a generator replacement. In total, CEZ plans 271 investment events for Temelín this year – 46 more than in 2022. During the current outage at unit 2 engineers are planning almost 15,000 activities, including 69 investment projects. Including suppliers, approximately 1,000 people will be involved in the work. Unit 1 was shut down for around two months earlier this year for refuelling.
The project to move towards an 18-month fuel cycle began in 2018, and should be completed by 2025. In total, CEZ is investing approximately CZK6bn ($262m) in Dukovany and Temelín in connection with the planned 60-year operation this year. The Dukovany NPP is expected to operate at least until 2047, Temelín 13 years longer.
Image: Temelín 2 is transitioning from a 12-month to an 18-month fuel cycle as part of a wider programme to increase efficiency and move towards a 60-year operating life (courtesy of CEZ)