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Mühleberg decommissioning on track: Waste & Recycling

July 14, 2022

With fuel removal continuing on schedule at the Mühleberg nuclear power plant, the Swiss utility BKW has submitted an application for the second of three dismantling phases of the plant. Mühleberg is the first nuclear power plant in Switzerland to be decommissioned.

The removal of fuel from the Mühleberg storage pool (Image: BKW)

The plant – consisting of a single 373 MWe boiling water reactor – started operations in 1972 and was shut down on December 20, 2019. Dismantling operations began on January 6, 2020. However, it is only considered to be definitely out of service only since September 15, 2020, the date on which its operating permit was replaced by a dismantling order.

Mühleberg will be dismantled in three dismantling phases (SP). SP1 lasts until all fuel assemblies from the plant have been removed, which is expected in 2024. The Federal Nuclear Safety Inspectorate (ENSI) approved SP1 in June 2020. SP2 ends with lifting or clearing of controlled areas, probably around 2030. SP3 includes work to demonstrate that the system is no longer a source of radiological hazard, which is planned for 2031.

The evacuation of the fuel assemblies from the power plant to the Zwilag intermediate storage facility in Würenlingen started as planned in April 2022 and will last approximately two years. The first two of a total of eight fuel removal campaigns have been successfully completed, with 102 of Mühleberg’s 418 fuel assemblies already transferred to Zwilag. There they were successfully reloaded into two Castor storage casks.

Large parts of the plant, such as turbines and generators, have been removed from the turbine building to make way for dismantled materials handling facilities. In the reactor building, several hundred tons of material above the reactor were removed. In addition, systems that have become obsolete are dismantled at many points in the reactor and turbine buildings. Over the past two and a half years, 4,800 tons of equipment have been dismantled.

In anticipation of the completion of the fuel transfer in early 2024, BKW submitted its request to ENSI for the second phase of dismantling at the end of June.

During this phase, all remaining components of the plant that have come into contact with radioactivity will be dismantled, treated and cleaned. These are, for example, the reactor vessel, parts of the containment or the fuel element storage pool that have become useless.

By the end of 2030, Mühleberg will be free of radioactive materials and conventional dismantling should start in 2031. BKW plans to submit a request for conventional dismantling to the authorities by 2027.

The site should be available for other uses from 2034.

Research and writing by World Nuclear News