Beznau NPP: Unit 1 back in operation after overhaul

20.06.2024 - The Beznau nuclear power plant (KKB) has completed the overhaul of Block 1. The Swiss Federal Nuclear Safety Inspectorate (ENSI) has given the go-ahead for the resumption of operations. KKB 1 is thus starting a new operating cycle and will continue to make an important contribution to the secure supply of electricity in Switzerland.

The inspection focussed on maintenance work, recurring tests and inspections. Particular attention was paid to the core internals and the reactor pressure vessel feedthroughs. The emergency system now also has a newly overhauled diesel unit. Of the total of 121 fuel elements, 20 were replaced.

The overhaul work was supervised by the nuclear supervisory authority ENSI and the Swiss Association for Technical Inspections SVTI. The core loading was verified by the International Atomic Energy Agency (IAEA) and the Swiss Federal Office of Energy (SFOE).

Following ENSI's approval, KKB 1 will gradually resume power operation. During the restart, water vapour is occasionally visible above the non-nuclear part of the plant (nacelle). There is no danger to people or the environment.

The Beznau nuclear power plant produces around 6 terawatt hours of electricity a year in a safe, reliable and climate-friendly manner, covering a tenth of Switzerland's electricity requirements. The two power plant units are taken off the grid each spring/summer for refuelling or maintenance. They then make an important contribution to Switzerland's secure supply of electricity for around a year - especially during the winter months.