Mochovce Unit 4 completes reactor assembly and heads for start-up

Slovakia has moved closer to completing a nuclear project worth approximately EUR 6.7 billion. Under the current schedule, Mochovce Unit 4 is expected to deliver its first electricity to the grid at the end of summer 2026.

Slovenské elektrárne has completed the assembly and hermetic sealing of the reactor at Unit 4 of the Mochovce nuclear power plant. Following the loading of all 349 fuel assemblies, technicians installed and connected the plant systems, closed the reactor vessel and carried out inspections which, according to the operator, confirmed that the primary circuit is ready for the next phase of start-up.

The completion of assembly marks the end of one of the key stages of physical start-up. This will be followed by strength and leak-tightness tests of the primary circuit, pre-critical tests, and then the achievement of first criticality and subsequent stabilisation of the reactor at minimum controlled power (MCP).