The plant this week announced it has reduced its energy production by more than 10 per cent because of the record temperatures in Switzerland. The hottest summer since 1864 has seen water temperatures in many water bodies rise above 23 degrees Celsius, threatening aquatic fauna, and now energy supplies.

“We have reduced the reactors' power to 89 per cent,” Tobias Habegger, a spokesman for the BKW Group, the energy company that manages the plant, told Swiss news portal 20 Minutes.

The Mühleberg Nuclear Power Plant is obliged by law to reduce production once temperatures in the Aare river exceed 20.5 degrees Celsius. This is the second reduction – already on July 5th the power plant was ordered to reduce production as a safety precaution, according to the same report. 

The nuclear power station in Mühleberg is the first to have had to curtail production because of the current heatwave. The nearby power plant in Beznau is functioning normally. That plant only has to take similar safety precautions once temperatures in the Aare river exceed 32 Celsius. 

The Mühleberg Nuclear Power Plant, which has been active since 1972, will be the first in Switzerland to be disconnected as of December 2019, according to a statement by the BKW Group. 

READ MORE: Sizzling temperatures leading to 'catastrophe' for fish in Swiss lakes and rivers 

Correction, July 31st: This article originally stated that the reactor was struggling to cool the plant and has since been amended. The article has also been updated to reflect that The Mühleberg Nuclear Power Plant only has one reactor. The reduction in production is simply in order to comply with the authority‘s requirement to protect the rivers flora and fauna and not further increase the river’s temperature.