Nuclear power in Switzerland

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Switzerland Nuclear power plants (view)
Location dot red.svg Active plants
Location dot purple.svg Closed plants
The emergency switch-off button of the Beznau Nuclear Power Plant. In 2011, the federal authorities decided to gradually phase out nuclear power in Switzerland.

Switzerland has four nuclear power plants, with five reactors in operation as of 2008. These plants produced 26.3 TWh in 2007 (up 19.5% from 2005, when 22.0 TWh were produced). Nuclear power accounts for 39.9% of the total production of electricity (65.9 TWh) in the country; the rest was produced by hydroelectric plants (55.2%) and conventional thermal or other plants (4.9%).[1] Switzerland expanded the production of its exising units through an uprate, increasing capacity by 13.4%.[2]

In addition, there are a number of research reactors in Switzerland, such as the CROCUS reactor at the École Polytechnique Fédérale de Lausanne. Switzerland uses nuclear energy only for peaceful purposes. Any project for the adoption of nuclear weapons was definitively dropped in 1988.[3][4]

In 2011, the federal authorities decided to gradually phase out nuclear power in Switzerland as a consequence of the Fukushima accident in Japan. In late 2013 the operator BKW decided to cease all electrical generation in 2019 in the Mühleberg plant, which has a similar design to Fukushima. Axpo is expected to come up with a similar decision for its aging Beznau Nuclear Power Plant, which houses the oldest commercial reactor of the world.


Power reactors[edit]

Switzerland has four nuclear power plants with five reactors in operation as of 2008: (Beznau and Gosgen also produce district heating in addition to power production)[5]

  • Beznau 1 (1969) and Beznau 2 (1972) (PWR) - 365 MWe each - Plant safety (each unit): Double containment, large dry; 3 trains safety injection, high and low pressure; 3 trains emergency feedwater; part of these ECCS-systems in a bunkerised building; possibilities to connect external water sources
  • Mühleberg (KKM) (1972) (BWR) - 355 MWe - Plant safety: Double containment, pressure suppression (Torus, with water pool of 2200 m3); 4 trains Low pressure core spray; 4 trains RHR (Torus-cooling); 2 turbine-driven HP-systems; part of the ECCS-systems bunkerised; possibilities to connect external water sources
  • Gösgen (KKG) (1979) (PWR) - 970 MWe - Plant safety: Double containment, large dry; 4 trains for high and low pressure safety injection (50% each); 4 trains emergency feedwater (50% each); 2 additional trains emergency feedwater; part of these ECCS-systems bunkerised; possibilities to connect external water sources
  • Leibstadt (KKL) (1984) (BWR) - 1165 MWe - Safety: Double containment (with additional Wet-Well), pressure suppression (water pool of 4000 m3); 4 trains (50% each) Low pressure injection (with 2 trains RHR), 2 diverse trains High pressure injection; 1 additional train with 2 pumps emergency injection (with 1 train RHR); nearly all the ECCS-systems bunkerised; possibility to connect external water sources.

The Mühleberg reactor is owned by BKW (Bernische Kraftwerke AG), majority-owned by the Bern canton. The Beznau reactors are owned by the Axpo Holding, that also control major parts of Leibstadt. Alpiq own 40% of Gosgen and 27.4% of Leibstadt.[6]

Decommissioned reactors[edit]

Research and teaching reactors[edit]

  • SAPHIR - The reactors that became known as SAPHIR was a 10-100 kW-range swimming-pool reactor of demonstration brought to Switzerland by the U.S. delegation to the First Conference on the Peaceful Uses of Atomic Energy that took place in Geneva in August 1955. It has been the first reactor ever shown in operation to the public, worldwide. After the conference the reactor was purchased by the Swiss government on behalf of Reaktor AG, a consortium interested in the development of nuclear energy in Switzerland. The reactor was moved to Würenlingen on the location of the future Paul Scherrer Institut and received its name, SAPHIR, on May 17, 1957. (The name of the reactor was inspired by the color of the Cherenkov radiation which was visible when the reactor was in operation.) Operable until 1994
  • DIORIT - A small heavy water reactor for research, operated 1960 to 1977 at former EIR Würenlingen. There was also, in the context of Cold War, the theoretical idea of producing weapons grade Plutonium in it, besides its research purpose.
  • Proteus - New research reactor of the 1990s at the Paul Scherrer Institute, Würenlingen.
  • CROCUS (46°31′16″N 6°34′13″E / 46.521238°N 6.570361°E / 46.521238; 6.570361 (Crocus reactor)) - CROCUS is a null-power (licensed to 100 W max power) LWR used for teaching at the École Polytechnique Fédérale de Lausanne (EPFL). CROCUS is a critical assembly, built in part from the elements of a dismantled subcritical assembly: Cactus. The name of the latter originated for the numerous instrumentation bars that came out of the core. CROCUS is another name in the XXXus series for nuclear installations at EPFL, e.g. the D-T nuclear fusion facility: Lotus.


Extending across the north and south side of the Alps, Switzerland lies at the junction of the Apulian and Eurasian tectonic plates, and there are many active seismic areas under the mountains that show that stresses continue to be released along deep fault lines. The 1356 Basel earthquake is the most significant seismological event to have occurred in Central Europe in recorded history[7] and may have had a Mw magnitude as strong as 7.1.[8]

Between 2002 and 2004 a major study was conducted to assess the seismic risk to Swiss nuclear power plants. The PEGASOS study, which cost around 10 million Swiss Francs (approximately $11 million) and which was conducted by 21 European experts with American involvement,[8] concluded that the earthquake risk in Switzerland is twice as large as had been previously thought.[9]

In 2011, following the nuclear emergencies at Japan's Fukushima I Nuclear Power Plant and other nuclear facilities Swiss Federal Councillor Doris Leuthard announced on 14 March a freeze in the authorisation procedures for three new nuclear power plants (see Politics), and ordered a safety review of the country's existing plants.[10]

There is also ongoing concern in Switzerland over the seismic risks of the Fessenheim Nuclear Power Plant, located in France approximately 40 km (25 mi) from the Swiss border. Following Fukushima the Swiss cantons of Basel-Stadt, Basel-Landschaft and Jura asked the French government to suspend the operation of Fessenheim while undertaking a safety review based on the lessons learned from Japan.[11] On April 6 the Grand Council of Basel-Stadt went further and voted for the plant to be closed.[12]


In Switzerland there have been many referenda on the topic of nuclear energy, beginning in 1979 with a citizens' initiative for nuclear safety, which was rejected. In 1984, there was a vote on an initiative "for a future without further nuclear power stations" with the result being a 55 to 45% vote against. On September 23, 1990 Switzerland had two more referenda about nuclear power. The initiative "stop the construction of nuclear power stations," which proposed a ten-year moratorium on the construction of new nuclear power plants, was passed with 54.5% to 45.5%. The initiative for a phase-out was rejected with by 53% to 47.1%. In 2000 there was a vote on a Green Tax for support of solar energy. It was rejected by 67% to 31%.

On May 18, 2003, there were two referenda: "Electricity without Nuclear," asking for a decision on a nuclear power phase-out, and "Moratorium Plus," for an extension of the earlier decided moratorium on the construction of new nuclear power plants. Both were turned down. The results were: Moratorium Plus: 41.6% Yes, 58.4% No; Electricity without Nuclear: 33.7% Yes, 66.3% No.[13] The program of the "Electricity without Nuclear" petition was to shut down all nuclear power stations by 2033, starting with Unit 1 and 2 of Beznau nuclear power stations, Mühleberg in 2005, Gösgen in 2009, and Leibstadt in 2014. "Moratorium Plus" was for an extension of the moratorium for another 10 years, and additionally a condition to stop the present reactors after 40 years of operation. In order to extend the 40 years by 10 more years another referendum would have to be held. The rejection of the Moratorium Plus had come to surprise to many, as opinion polls before the referendum have showed acceptance. Reasons for the rejections in both cases were seen in the worsened economic situation.[14]

On June 10, 2008, ATEL submitted an application to the Swiss Federal Office of Energy for the construction of a new plant in the Niederamt region (SO).[15] A further two applications were to be presented by Axpo and BKW before the end of 2008.[16]

In May 2011, the Swiss government decided to abandon plans to build new nuclear reactors. The country’s five existing reactors will be allowed to continue operating, but will not be replaced at the end of their life span. The last will go offline in 2034.[17]


  1. ^ Schweizerische Elektrizitätsstatistik 2007
  2. ^
  3. ^ 7.4 States Formerly Possessing or Pursuing Nuclear Weapons
  4. ^ Swiss nuclear bomb International Physicians for the Prevention of Nuclear War October 9, 2010. Retrieved March 7, 2014
  5. ^
  6. ^
  7. ^ "The most damaging intra-plate earthquake known to have occurred in central Europe", according to (Risk Management Solutions) 1356 Basel Earthquake: 650-year Retrospective, 2006.
  8. ^ a b Centrale Nucléaire de Fessenheim : appréciation du risque sismique RÉSONANCE Ingénieurs-Conseils SA, published 2007-09-05, accessed 2011-03-30
  9. ^ Swiss search for strategy on nuclear BBC News, published 11-03-23, accessed 2011-04-16
  10. ^ Swiss Federal Council. "Energy Policy: The Federal Council orders a revision of decision processes after Fukushima (in French)". Swiss Federal Council. Retrieved 25 March 2011. 
  11. ^ Trois cantons suisses demandent l'arrêt de la centrale nucléaire de Fessenheim Associated Press on Yahoo!, published 2011-03-30, accessed 2011-03-30
  12. ^ Le Grand Conseil de Bâle-Ville exige l’arrêt de la centrale de Fessenheim. LeMatin, published 2011-04-06, accessed 2011-04-06.
  13. ^ Bundesamt für Energie BFE - Startseite
  14. ^
  15. ^
  16. ^
  17. ^ Kanter, James (2011-05-25). "Switzerland Decides on Nuclear Phase-Out". The New York Times. 

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