New Slovak nuclear unit Mochovce 4 reaches criticality for the first time

The fourth unit of Slovakia's Mochovce nuclear power plant has moved significantly closer to entering operation. The VVER-440 reactor has reached criticality and minimum controlled power for the first time. The unit will now undergo tests at various power levels. The new installed capacity of 471 MW (gross) will place Slovakia among the countries with the highest share of nuclear power in their energy mix.

Slovak energy company Slovenské elektrárne announced that its fourth unit at the Mochovce nuclear power plant had reached criticality for the first time. Technicians began commissioning the unit on 6 August; at 22:10, the reactor reached criticality for the first time, and 21 minutes later it reached minimum controlled power. This is one of the key commissioning milestones for every new unit.

"Achieving criticality and minimum controlled power is the result of the work of thousands of experts involved in the preparation, construction, inspection and commissioning of the fourth unit. It confirms that the plant is ready to proceed to the next phase of testing before electricity generation begins," said Mochovce plant project director Martin Mráz.