Long-term operation upgrades advanced during outage of Czech Dukovany Unit 3

On September 8, 2026, CEZ Group (CEZ) is utilizing the current outage maintenance window of Unit 3 at the Dukovany Nuclear Power Plant to carry out large-scale modernization of the turbine hall and secondary circuit. These systems are responsible for converting the thermal energy generated by the reactor into electricity and delivering it to the transmission grid.

CEZ stated that during this outage, technicians will perform hundreds of inspections, repairs, maintenance activities, and modifications on secondary circuit equipment. In addition to routine inspections required by regulations and operating procedures, preventive maintenance, defect resolution, and equipment upgrades will also be carried out on site, creating conditions for the plant's goal of operating for up to 80 years.

Roman Havlín, Director of the Dukovany Nuclear Power Plant, stated that while outage maintenance at nuclear power plants typically draws more attention to the reactor and primary circuit, the turbine hall equipment that ensures actual electricity generation is equally critical, and related equipment will also receive intensive maintenance during the outage.

The main tasks this year include: replacing compensators in the turbine extraction steam system, a task associated with the modernization of the low-pressure cylinders of both turbogenerators; refurbishing the upper chambers of the moisture separator reheaters; and modifying the support structures of feedwater and steam pipelines. At the same time, the site is also upgrading the control system of pulse safety valves, advancing the modernization of the chemical dosing system for operating media, and replacing equipment and cables approaching the end of their service life.

Bohdan Zronek, CEZ Board Member and Director of the Nuclear Energy Division, stated that to achieve the goal of operating for up to 80 years, key equipment must be maintained in good condition. In addition to the reactor, turbines, pipeline systems, and control systems also require continuous and timely upgrades to support long-term safe and efficient operation.

CEZ stated that the maintenance work on Unit 3 at Dukovany is progressing as planned. Once all inspections, tests, and necessary repairs are completed, the unit is expected to be reconnected to the grid by the end of September. Hundreds of workers from the plant and supplier organizations are participating in this outage maintenance.

The Dukovany Nuclear Power Plant has a total of four units, all of which are Russian-designed VVER V-213 reactors with an original net installed capacity of 420 MW each, having entered commercial operation between May 3, 1985, and July 19, 1987.

CEZ stated earlier this year that it has initiated preparations for the long-term operation of the Dukovany Nuclear Power Plant, with the goal of extending the operating life of all four units to a maximum of 80 years, potentially extending operation to around 2065–2067.