Dukovany nuclear power plant in Czechia raises output of its second unit

Power engineers have increased the output of the second unit at the Dukovany Nuclear Power Plant from 500 to 512 megawatts (MW). They have completed another stage of a project covering all four Dukovany units. The output of Unit 3 was increased in April this year, and modifications to the final unit will be completed next spring. This follows from a report published today by ČEZ.

Once the modifications to all units are complete, the plant’s annual generation is expected to rise by approximately 300 000 megawatt-hours (MWh), or 0.3 terawatt-hours (TWh), according to the company. The Dukovany plant generated 14.3 TWh of electricity last year.

Dukovany’s second unit was shut down until the beginning of August for a planned partial fuel replacement, equipment inspections and maintenance. Inspections and tests during its start-up confirmed safe operation and enabled an increase in the reactor’s thermal output. “As a result, we are achieving the highest electricity generation in the plant’s history,” said plant director Roman Havlín.

Following the modifications, the water temperature at the reactor outlet rose by around two degrees to 300.4 degrees Celsius. Under optimal conditions, this means an increase of 12 MW in electrical output. The plant plans to increase the output of Unit 1 later this year and that of its final unit, Unit 4, next spring, the director said.

“Seemingly small changes to the parameters will bring us hundreds of thousands of additional megawatts of electricity per year. A major benefit of increasing output is that, after safety margins were confirmed, no major investment in equipment was needed,” said Bohdan Zronek, ČEZ board member and director of the nuclear energy division.

When the Dukovany units entered service between 1985 and 1987, they had an electrical output of 440 MW. Subsequent equipment upgrades enabled power engineers to raise the installed capacity of each Dukovany unit to 500 MW. At Temelín, the electrical output of both units increased from 981 MW to the current 1086 MW.

Czechia has six nuclear units at two power plants. Dukovany generated 14.3 TWh of electricity last year, while Temelín exceeded 16 TWh.

ČEZ is preparing to build two new units at Dukovany, with the first expected to be completed in 2036. The contractor will be South Korea’s KHNP, which the Czech government selected over France’s EDF in the tender. The contract to build the reactors at Dukovany is expected to be signed by the end of March next year.