KKB 1 back on the grid after fuel element replacement

02.06.2023 - After successfully replacing fuel elements, Axpo reconnected Block 1 of the Beznau nuclear power plant (KKB) to the grid yesterday. With the reactor core reloaded, KKB 1 will start its next operating cycle – which, in the coming months, will see it play a crucial role in security of supply in Switzerland.

Block 1 was disconnected from the grid on 16 May 2023 for a scheduled fuel element replacement. Over the past two weeks, KKB specialists replaced 16 of the total 121 fuel elements in the reactor core. Checks, system tests and scheduled maintenance works were performed on individual components too. Around 150 external experts assisted the 500 or so members of staff at KKB.

Following approval by the Swiss Federal Nuclear Safety Inspectorate (ENSI), KKB 1 has gradually returned to power operation. The plant will reach full capacity (365 megawatt net capacity) in roughly two days.

As the plant powers up again, steam will be visible above the non-nuclear part of the plant (engine room) at times. There is no danger to people or the environment.

The Beznau nuclear power plant produces around 6 terawatt hours of electricity, safely and reliably, every year – which meets about one tenth of Switzerland’s power requirements. The two power plant blocks are taken off grid separately in spring/summer for fuel element replacement or review. They then resume their contribution to Switzerland’s security of supply for around another year, something which is particularly vital in the winter months.