Czech Dukovany plant shuts down third unit, with fourth to follow in August

A planned outage of Unit 3 is beginning at the Dukovany Nuclear Power Plant. Nuclear specialists will replace some of the reactor fuel and carry out equipment inspections and maintenance. In August, they will also shut down neighboring Unit 4 for about a month to carry out work on equipment shared by both units. The plant’s spokesperson, Radek Doležal, told ČTK today. He added that, according to the plan, a similar overlap of outages is not expected again until 2032.

The Dukovany power plant has four units. “This year’s outage of Unit 3 is among the more technically demanding. In addition to standard inspections and maintenance, we will work on safety systems, clean a steam generator and carry out dozens of investment projects,” plant director Roman Havlín said. Subject to the results of inspections, the outage should be completed by the end of September.

After Unit 3 is shut down, specialists will remove all the fuel from the reactor core and lower the water level in the reactor to allow maintenance of valves in the reactor core cooling system. The work will also include cleaning steam generator PG2 in cooperation with Framatome.

During the outage, workers will carry out 50 investment projects. All major projects are related to improving safety, modernizing equipment or extending the plant’s operating life. They include, for example, upgrades to residual heat removal systems, modernization of electrical protection systems for safety switchboards, replacement of cables nearing the end of their service life, and modifications to long-term heat removal systems, ČEZ said.

In recent years, ČEZ Group’s nuclear power plants have gradually switched to extended fuel cycles. At Dukovany, a 16-month fuel cycle has been standard since 2024: units operate for 14 months between outages, followed by an outage lasting more than a month. Temelín will complete its transition to an 18-month fuel cycle this year. The aim is to increase total electricity generation, use nuclear fuel more efficiently and reduce the strain on equipment.

Temelín and Dukovany generated a total of 32.066 terawatt-hours (TWh) of electricity last year, including 14.68 TWh at Dukovany. So far this year, the Dukovany plant has supplied 8.087 TWh of electricity.

The four Dukovany units were commissioned between 1985 and 1987. ČEZ expects them to be able to operate for up to 80 years from startup, meaning until 2065 to 2067. South Korea’s KHNP will build two more units near Dukovany.