Could the operating life of existing nuclear power plants be extended?

The decision to phase out nuclear power does not set a date for the shutdown of our nuclear plants. They will therefore be able to continue operating as long as their safety is guaranteed. With the exception of Mühleberg, which was shut down in December 2019, the other four reactors could be operated until their 60th year.

Switzerland has five nuclear reactors, located at the sites of four power plants: Beznau I (commissioned: 1969) and Beznau II (1971), Mühleberg (1972), Gösgen (1979) and Leibstadt (1984). Beznau I is currently (in 2020) the oldest operating civilian nuclear power plant in the world.

In accordance with Swiss nuclear energy legislation, a nuclear power plant may remain in operation as long as it meets the legal safety requirements. The law does not provide for any pre-defined limitation on the operating life. The decision to phase out nuclear power therefore does not set a specific date for the definitive shutdown of our power plants, but merely specifies that no new nuclear power plants may be built.

From a purely technical point of view, the service life of nuclear power plants depends essentially on the aging of the reactor vessel, which is not replaceable. Other equipment is replaced as long as the investment costs for safety remain acceptable. When this is no longer the case, the operator then decides on the final shutdown of the plant. This is the case for the Mühleberg power plant, which the operator decided to shut down in December 2019, i.e. after 47 years of operation. It should be noted that the older the power plants become, the more difficult it becomes to find certain spare parts on the market. There will also be a shortage of specialists, as few young people are likely to want to train in a sector that is doomed to be abandoned.

Our nuclear power plants are under the supervision of the Swiss Federal Nuclear Safety Inspectorate (ENSI), an independent technical inspection body, which periodically inspects the power plants and grants them the right to continue operation. Following its inspection in 2014, ENSI estimated that all of our power plants, except Mühleberg, are currently technically capable of continued operation for 60 years. This projected lifetime would result in the following schedule for the final shutdown of these power plants: Beznau I (2029), Beznau II (2031), Gösgen (2039) and Leibstadt (2044).

If the operators of these power plants do not want an “early” shutdown, and if ENSI does not demand it, then only a new political decision could force them to do so. It is likely that the Swiss will have to decide in a referendum on the question of how long our nuclear power plants will be in operation in the coming decade.