High water temperatures: Unit 1 of the Beznau Nuclear Power Plant (KKB) shut down

02.07.2025 - Axpo has shut down Block 1 of the Beznau nuclear power plant to protect the ecosystem from further warming of the River Aare. Block 2 is currently operating at 50 % capacity. 

Due to the high river water temperatures, Axpo has been increasingly reducing the output of the two reactor units at the Beznau nuclear power plant for days and reduced it to 50 % on Sunday. Yesterday afternoon, Axpo shut down KKB1 and continued operation of KKB2 at reduced output (50 %). The temperature of the River Aare remained below 25 °C yesterday after the cooling water had been discharged and largely mixed. The current measures will be maintained for the time being. Axpo is constantly monitoring the development of water temperatures.

The measures for throttling and complete shutdown are being taken in accordance with the SFOE's instructions. They serve to protect the ecosystem of the Aare and ensure compliance with the strict environmental regulations. Excessive warming of the already warm watercourse is to be prevented during hot summer periods so as not to put additional strain on flora and fauna.