Czech Dukovany plant raises third unit’s thermal output, enabling more electricity

At the Dukovany Nuclear Power Plant, operators have for the first time increased the thermal output of one unit to 1475 megawatts (MW), 2.3 percent higher than before. It is unit three. ČEZ plans to make the same adjustments to the remaining three units. Dukovany’s annual electricity generation could then rise by 0.3 terawatt-hours (TWh). Plant spokesperson Jiří Bezděk told CTK today. Last year, the Dukovany plant supplied 14.3 TWh of electricity to the grid.

The temperature of the water exiting the reactor in unit three has now risen by approximately two degrees to 300.4 degrees Celsius. The unit had an electrical output of 500 MW; with the increase in thermal output, it could reach up to 511 MW under optimal conditions.

„We want to raise output to the new standard during the outages of unit two later this year and unit one at the end of the year. We would like to complete the project next year,“ said Roman Havlín, director of the Dukovany plant.

If the plant successfully completes all the tests, its electricity generation could increase by 300.000 MWh starting next year.

According to ČEZ, the increase in output at Dukovany’s third reactor unit followed several years of preparations, including detailed calculations and analyses of safety parameters, as well as upgrades to technological and safety systems. The company says this will not increase fuel consumption.

„Seemingly small changes to the parameters will bring us hundreds of thousands of megawatts of electricity a year. Preparing for operation at higher output required confirmation of the safety analyses, but no major investments were necessary,“ said Bohdan Zronek, a member of the ČEZ board and director of its nuclear energy division.

When the units entered service between 1985 and 1987, the Dukovany Nuclear Power Plant’s electrical output was 440 MW per unit. Fifteen years ago, through equipment upgrades and by using available reserves, operators increased the installed output of each Dukovany unit to 500 MW. At Temelín, the electrical output of both units rose from 981 MW to the current 1086 MW.

„Through upgrades at our nuclear power plants, we have figuratively managed to build a large coal-fired power plant or a smaller nuclear unit. The current increase in output at Dukovany follows the same trend,“ said ČEZ CEO Daniel Beneš.

Safety is the priority, he said. „We would never take such a step without confirmation of the safety parameters,“ he said.

All four units are currently generating electricity at Dukovany, while one unit is operating at Temelín. Temelín’s second unit is offline for refuelling and equipment maintenance. ČEZ is preparing to build a new nuclear power source at Dukovany and is selecting a supplier. The first new reactor there is expected to start operating in 2036.

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