Lucens reactor

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Lucens reactor
Control room - Lucens reactor - 1968 - L17-0251-0105.jpg
Control room of the Lucens reactor in April 1968
Lucens reactor is located in Switzerland
Lucens reactor
Location of Lucens reactor
Official name Versuchsatomkraftwerk Lucens
Country Switzerland
Location Lucens, Vaud
Coordinates 46°41′34.16″N 6°49′36.81″E / 46.6928222°N 6.8268917°E / 46.6928222; 6.8268917Coordinates: 46°41′34.16″N 6°49′36.81″E / 46.6928222°N 6.8268917°E / 46.6928222; 6.8268917
Status Decommissioned
Construction began 1 April 1962 (1962-04-01)
Commission date 10 May 1968 (1968-05-10)
Decommission date 3 March 1969 (1969-03-03)
Owner(s) Nationale Gesellschaft zur Förderung der industriellen Atomtechnik
Operator(s) Energie Ouest Suisse
Nuclear power station
Reactor type HWGCR
Reactor supplier Thermatom
Fuel type Low enriched uranium
Cooling source Carbon dioxide
Power generation
Units decommissioned 1 x 6 MW[1]
Nameplate capacity 6 MW
Suffered a nuclear accident on 21 January 1969, leading to a partial core meltdown and massive radioactive contamination

The Lucens reactor was a 6 MW experimental nuclear power reactor built next to Lucens, Vaud, Switzerland. After its connection to the electrical grid on 29 January 1968, the reactor only operated for a few months before it suffered a loss-of-coolant accident on 21 January 1969, leading to the meltdown of one of the five fuel elements [2] and radioactive contamination of the cavern.[1]


In 1962 the construction of a Swiss-designed pilot nuclear power plant began.[1][3][4][5] The heavy-water moderated, carbon dioxide gas-cooled reactor was built in an underground cavern.[6] It produced 28 MW of heat, which was used to generate 6 MW of electricity, and it became critical 29 December 1966.[1] It was fueled by 0.96% enriched uranium alloyed with chromium cased in magnesium alloy (magnesium with 0.6% zirconium) inserted into a graphite matrix. Carbon dioxide gas was pumped into the top of the channels at 6.28 MPa and 223 °C and exited the channels at a pressure of 5.79 MPa and at a temperature of 378 °C.[7]

Nuclear accident

Switzerland Nuclear power plants (view)
Location dot red.svg Active plants
Location dot purple.svg Closed plants

It was intended to operate until the end of 1969, but during a startup on 21 January 1969, it suffered a loss-of-coolant accident, leading to a partial core meltdown and the radioactive contamination of the cavern, which was then sealed.[8] Using the criteria of the International Nuclear Event Scale, introduced in 1990 by the International Atomic Energy Agency, the event has been assessed as a Level 4 "Accident with local consequences".[9]

The accident was caused by water condensation forming on some of the magnesium alloy fuel element components during shutdown and corroding them. The corrosion products from this accumulated in some of the fuel channels. One of the vertical fuel channels was sufficiently blocked by it to impede the flow of carbon dioxide coolant so that the magnesium alloy cladding melted and further blocked the channel. The increase in temperature and exposure of the uranium metal fuel to the coolant eventually caused the fuel to catch fire in the carbon dioxide coolant atmosphere. The pressure tube surrounding the fuel channel split because of overheating and bowing of the burning fuel assembly, and the carbon dioxide coolant leaked out of the reactor.[10][11]

No irradiation of workers or the population occurred, though the cavern containing the reactor was seriously contaminated. The cavern was decontaminated and the reactor dismantled over the next few years. The plant was totally decommissioned in 1988 and the last radioactive waste was removed in 2003.[12][13]

See also


  1. ^ a b c d "LUCENS – Reactor Details". IAEA Power Reactor Information System. International Atomic Energy Agency. Retrieved 2016-10-08. 
  2. ^ J. Wolters: Aufgetretene Unfälle mit Kernschäden; in Atomwirtschaft, Juni 1987
  3. ^ Anthony, L. J. (1966). Sources of Information on Atomic Energy – International Series of Monographs in Library and Information Science. 2. Elsevier. p. 85. ISBN 978-1-4831-5600-2. 
  4. ^ Wildi, Tobias (2003). "Der Traum vom eigenen Reaktor – die schweizerische Atomtechnologieentwicklung 1945–1969" (PDF). PhD dissertation (in German). Chronos. doi:10.3929/ethz-a-004459704. ISBN 3-0340-0594-6. 
  5. ^ Hug, Peter (2009). "Energie nucléaire". Dictionnaire historique de la Suisse (in French). Hauterive: Gilles Attinger. Retrieved 2016-10-09. 
  6. ^ Summary of Swiss nuclear reactors, SAPIERR Support Action: Pilot Initiative for European Regional Repositories Archived 19 July 2011 at the Wayback Machine.
  7. ^ Heavy water reactors : status and projected development (PDF). Vienna: International Atomic Energy Agency. 2002. ISBN 9201115024. 
  8. ^ J. Wolters: Aufgetretene Unfälle mit Kernschäden; in Atomwirtschaft, Juni 1987
  9. ^ Ha-Duong, Minh; Journé, Venance (2014-05-14). "Calculating nuclear accident probabilities from empirical frequencies". Environment Systems and Decisions. 34 (2): 249–258. doi:10.1007/s10669-014-9499-0. ISSN 2194-5403. 
  10. ^ Description of events, Nuclear tourist
  11. ^ Heavy water reactors: Status and projected development Archived 13 April 2007 at the Wayback Machine., IAEA, 2002
  12. ^ "On-site disposal as a decommissioning strategy" (PDF). International Atomic Energy Agency. November 1999: 67. Retrieved 6 January 2013. 
  13. ^ "Switzerland's first nuclear plant decommissioned". SWI Retrieved 2016-10-11. 

External links

  • Maps of Nuclear Power Reactors: Switzerland
  • Major Nuclear Power Plant Accidents

Retrieved from ""
This content was retrieved from Wikipedia :
This page is based on the copyrighted Wikipedia article "Lucens reactor"; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA