Slovakian utility Slovenské Elektrárne has started operating unit 3 of the Mochovce nuclear power plant at full power.

According to the company,  the start-up process for the VVER-440 reactors involves gradual increases in power, with tests carried out to ensure efficacy at each level of power output.

In February 2023, unit 3’s power was increased to 35% of overall capacity, then to 55% in March, 75% in July and 90% in August. The Slovak Nuclear Regulatory Authority told Slovenské Elektrárne it could now raise reactor output to 100%. The company will perform a 144-hour trial run with power at maximum capacity.

Peter Farkaš, operations manager at the Mochovce plant, said: “After demanding tests required to prove the safe operation of unit 3, we have reached the final stage. Full-scale tests are planned for the end of September and the beginning of October, including the 144-hour trial run. All tests have so far confirmed the readiness of the new unit for long-term safe and CO₂-free power generation.”

Construction of the first two units of the Mochovce plant began in 1982, using VVER-440 V-213 reactor units. Units 1 and 2 became operational in 1998 and 1999, respectively. By June 2008, after assistance from Western companies with upgrades, Mochovce 1 and 2 produced 436MW.

Work on units 3 and 4 started in 1986 but halted in 1992. Construction began again in 2009, but due to political wrangling, including opposition from Austrian environmental organisation Global 2000, it was not finished until 2021. Output began in October 2022. Unit 4 is scheduled to reach maximum output up to two years after unit 3. When all units are operating at full capacity, each will be able to provide 13% of Slovakia’s electricity needs.

Recently, Canada granted Romania C$3bn (10.5bn lei) to develop nuclear power infrastructure. This will be used to build units 3 and 4 of the Cernavoda plant, which will generate 36% of Romania’s electricity upon completion.