The first phase of decommissioning has begun at Switzerland’s Mühleberg nuclear power station after the single-unit boiling water reactor ended service on 15 September.

The 373-MW unit, which began commercial operation in November 1972, was permanently shut down on 20 December 2019, but only now has officially been declared “out of service”.

Swiss nuclear regulator Ensi said the plant’s operating licence has been replaced by a decommissioning order issued by the Federal Department of the Environment, Transport, Energy and Communications.

Swiss legislation defines shutdown – December 2019 in this case – as the time when electricity production ceases and the nuclear power plant is permanently taken offline. The plant has now formally been designated as non-operational and the owner, BKW Energie, is legally obliged to decommission it.