Czech power utility ČEZ is shutting unit 3 of the Dukovany NPP for scheduled maintenance, equipment inspections and the replacement of part of the fuel with fresh fuel. Since its launch in 1987, this will be the 36th shutdown for fuel change. Since January 2023, Dukovany’s four VVER-440 units have extended their fuel campaigns from 11 to 15 months. The engineers expect the shutdown to end during April, but the exact date of the resumption of production will depend on the results of the inspections and tests.
The work will involve a total of 15,000 tasks including to check, verify and test thousands of devices and components for the next few months of safe and reliable operation of the unit. “In addition to standard maintenance, we also have 54 technical and investment actions as part of the shutdown of the third unit, which will contribute to the further modernisation of part of the equipment to ensure reliability during the next stage of power plant operation,” said Dukovany Director Roman Havlín.
The most time-consuming and technically demanding activities include checking the tightness of the thermocouple surfaces of steam generators, general maintenance of two of the six main circulation pumps, a three-year general overhaul of diesel generator number 9 and inspection of blades and equipment of both turbosets.
In addition, new power engineers will start replacing unit section switchboards with a voltage of 0.38 kV at all four units as part of ensuring at least 60 years of operation, ČEZ noted. This will take place in two stages. Completion the first stage is planned for 2028 and will cost CZK400m ($17m). “We will operate our nuclear power plants for at least 60 years, and we are adapting the scope of maintenance and investment to this,” said Bohdan Zronek, member of the ČEZ Board and Director of the Nuclear Energy Division.
