New Slovak nuclear unit Mochovce 3 officially enters commercial operation

Slovak nuclear unit Mochovce 3 officially entered commercial operation after successfully completing a 144-hour operational test. Construction of the VVER-440 unit began in 1986, but it was mothballed for more than 20 years. Thanks to the new unit, Slovakia will cover 13% of its electricity consumption with emissions-free power and cease to be a net importer of electricity.

Slovenské Elektrárne announced that its new Mochovce 3 unit successfully completed the commissioning and trial operation phase on 17 October and entered commercial operation. During the final 144-hour test at full power, technicians monitored whether the unit safely met its design parameters.

“I am proud and pleased to announce the successful completion of the final operational test at Mochovce 3. The third unit is an important pillar of our efforts to ensure a stable and secure electricity supply for Slovakia. I thank all our employees and partners for their tireless work and commitment, which made this success possible. We believe that Unit 3 will make a long-term contribution to Slovakia’s energy mix and help us meet our climate change commitments,” said Branislav Strýček, chairman of the board and CEO of Slovenské Elektrárne.

The company began the unit’s phase of active testing in September last year. During this phase, the unit underwent more than a hundred different trials and tests. Since its first delivery to the grid at the end of January, it has generated more than 1.2 TWh of electricity.

The Russian-designed VVER-440 unit has a total electrical output of 471 MW gross and 440 MW net. The facility has a planned service life of 60 years and is expected to generate electricity until 2083. With the new generation at Mochovce, Slovakia can stop relying on electricity imports from abroad.

“After more than twenty years, we have commissioned another nuclear unit in Slovakia. The commissioning process strengthened a team of nuclear experts from Slovakia and beyond. In a way, it is an exceptional team, because it also brought together colleagues who had experience commissioning units in the former Czechoslovakia. It is important that we pass the baton to the next generations and maintain the expertise needed for our country’s energy security,” said Juraj Krasňanský, director of completion and commissioning for Mochovce Units 3 and 4.

More than a twenty-year construction hiatus

Construction of the third and fourth units at the Mochovce nuclear power plant began in late 1986 and early 1987, when the country was still Czechoslovakia. However, progress was hampered by the collapse of Slovak Energy Enterprises, and after 1990 the work was aimed primarily at mothballing the unfinished project. Construction came to a complete halt in 1993 and remained suspended for more than twenty years. Work on the project resumed only after the partial privatization of Slovenské Elektrárne in 2005. Construction on both units restarted in mid-2009.

“With the completion of Unit 3’s commissioning, we welcome a new unit to our nuclear fleet. The plant successfully passed demanding tests, including disconnection from the electricity grid at full power. This means Unit 3 can handle such challenging situations as well. We are now preparing for its first scheduled outage and routine operational activities,” said Martin Mráz, director of AE Mochovce.