Slovakia's fourth Mochovce reactor sends first power to the grid

The fourth unit of Slovakia's Mochovce nuclear power plant supplied electricity to the national grid for the first time on October 15, operator Slovenske elektrarne (SE) said, the Slovak news agency TASR reported.

SE connected the first of the unit's two turbogenerators at 20:41 local time, with the reactor at 20% power. The reactor had reached minimum controlled power on August 6.

"For the first time in history, Mochovce unit 4 is supplying electricity to the Slovak electricity system," SE chairman and CEO Branislav Strycek said, World Nuclear News reported.

The 471 MW unit will cover about 13% of Slovakia's electricity consumption once it runs at full power, producing about 3.5 TWh a year, and adds to a system that already draws more than 60% of its electricity from five reactors. The government expects it to cement Slovakia's position as a net power exporter. Completing the third and fourth Mochovce units cost about €6.7bn, which SE calls one of the largest private investments in the country's history.

The connection came two days late. SE called off a connection planned for October 13, which Prime Minister Robert Fico had been due to attend, because a technical test had to be repeated, the Czech energy portal oEnergetice.cz reported.

Commissioning is not over. The second turbogenerator still has to be synchronised, followed by tests at rising power levels under the supervision of the Nuclear Regulatory Authority, ending with a 144-hour run at 100%. Strycek said in June that he expected the unit to reach full power in 2027.

The milestone also matters for SE's ownership. The Slovak state owns 34% of the utility and holds an option, dating from a 2015 memorandum with former co-owner Enel, to buy a further 17% within six months of the unit's completion. Fico said in April that he backs using it, which would return SE to majority state control. The remaining 66% is held by EPH, the energy group of Czech billionaire Daniel Kretinsky.

Mochovce 4 is a Soviet-designed VVER-440 reactor, a family whose fuel has long tied operators to Russian supply, one reason uranium is the new gas in the Kremlin's energy diplomacy.