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Gentilly Nuclear Generating Station

Coordinates: 46°23′45″N 72°21′25″W / 46.39583°N 72.35694°W / 46.39583; -72.35694
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Gentilly Nuclear Generating Station
The Gentilly-2 (left) and Gentilly-1 (right)
nuclear generating stations
Official nameCentrale nucléaire de Gentilly
LocationBécancour, Quebec
Coordinates46°23′45″N 72°21′25″W / 46.39583°N 72.35694°W / 46.39583; -72.35694
Statussafe storage (pools)
pending dismantling
Construction began1973
Commission dateOctober 1, 1983 (October 1, 1983)
Decommission dateDecember 28, 2012 (December 28, 2012)
Construction costCAD 1.3 billion
Nuclear power station
Reactor typeCANDU-BWR
Reactor supplierAtomic Energy of Canada Limited
Power generation
Units operationalNone
Units cancelled1 × 640 MW
Units decommissioned1 × 250 MW
1 × 675 MW
Nameplate capacity925 MW
Capacity factor76.4%
Annual net output3,491 GW·h
External links
WebsiteHydro-Québec: Gentilly-2
CommonsRelated media on Commons

Gentilly Nuclear Generating Station (Centrale nucléaire de Gentilly in French) is a former nuclear power station located on the south shore of the St. Lawrence River in Bécancour, Quebec, 100 km north east of Montreal. The site contained two nuclear reactors; Gentilly-1, a 250 MW CANDU-BWR prototype, was marred by technical problems and shut down in 1977, and Gentilly-2, a 675-MW CANDU-6 reactor operated commercially by the government-owned public utility Hydro-Québec between 1983 and 2012. These were the only power generating nuclear reactors in Quebec.[note 1]

The Gentilly reactors were constructed in stages between 1966 and 1983 and were originally part of a plan for 30-35 nuclear reactors in Quebec.[1][2] A third reactor, Gentilly-3, was scheduled to be built on the same site but was cancelled because of a drop in demand growth in the late 1970s.[3]

In October 2012, it was decided for economic reasons not to proceed with the refurbishment of Gentilly-2, and to decommission the power plant instead. The process will take approximately 50 years to complete.[4] In December of that same year, the remaining reactor was shut down and the decommissioning process started.[5]

In August 2023, Hydro-Québec reported it was assessing the state of the plant to determine whether or not the Gentilly-2 CANDU reactor could be recommissioned. This came as the province of Quebec looked towards options to increase its production of clean electricity.[6] It was decided to not proceed with recommissioning Gentilly-2 due to social acceptability issues.[7]



Gentilly-1 was a prototype CANDU-BWR reactor, based on the SGHWR design. It was designed for a net output of 250MW(e). The reactor had several features unique amongst CANDU reactors, including vertically oriented pressure tubes (allowing for the use of a single fuelling machine below the core), and light-water coolant. These features were intended to reduce the cost and complexity of the unit, again to make it an attractive export unit. However, the design was not successful, and over 7 years recorded only 180 on-power days. Gentilly-1 is no longer in operation.



Gentilly-2 was a standard CANDU 6 reactor, similar to the Point Lepreau Nuclear Generating Station. The plant had a net output of 675MW(e). Unlike the adjacent Gentilly-1 reactor, Gentilly-2 had a good service record since start-up in 1982, with a cumulative operating factor of 76.4%.[8]

In an August 19, 2008 announcement, Québec planned to spend $1.9B to overhaul Gentilly-2 in order to extend its lifespan to 2040.[9] Refurbishment of the reactor was eventually cancelled when on 3 October 2012, Hydro-Quebec's CEO, Thierry Vandal, announced the decommissioning of the Gentilly-2 generating station for economic reasons, scheduled to occur on 28 December 2012 at 10:30 p.m.[5][10] At that time, a decommissioning process will proceed over a period of 50 years and is expected to cost $1.8 billion.[11] The permanent shut down and decommissioning of the power plant followed an election pledge from Quebec premier Pauline Marois.[4]

The Gentilly site also houses a 411MW gas turbine generation plant. The Bécancour generating station was commissioned in 1992-1993.[12]



Gentilly-3 was a proposed nuclear reactor at the Gentilly site. It was cancelled by Quebec Premier René Lévesque.[13] A white book study published by the Parti Québécois (PQ) before ascending to power found that Gentilly-3 was not needed for Quebec's future energy needs and that it could be fulfilled with hydroelectricity.[14] After the election of the PQ government, a moratorium on construction of nuclear plants was put into place. The reactor had been scheduled to be completed before 1990, and was the last reactor firmly committed to by Hydro-Québec and the Province of Quebec, though Quebec had committed to buy enough heavy water for four Candu style reactors, processed by the La Prade heavy water plant (near Trois-Rivières), scheduled for 1982 opening.[15]

See also



  1. ^ There is also a SLOWPOKE research reactor at Montreal's École Polytechnique.
  1. ^ "Minister wants referendum on nuclear power plants". Calgary Herald. Canadian Press. 10 February 1977. Retrieved 2012-09-11.
  2. ^ Marie-Claude Fafard (15 September 2010). "Québec : le dangereux retour de l'énergie nucléaire ?". Afrique Expansion Magazine (in French). Archived from the original on 2014-10-30. Retrieved 2012-09-11.
  3. ^ Baril, Hélène (October 3, 2012). "Libéraux et péquistes, promoteurs du nucléaire au Québec". La Presse (in French). Montreal. Retrieved December 28, 2012.
  4. ^ a b Lapresse.ca. "Pauline Marois ferme Gentilly-2" (in French). Retrieved 2012-09-20.
  5. ^ a b Canadian Broadcasting Corporation (December 28, 2012). "Gentilly-2 nuclear plant shuts down after 29 years". CBC.ca. Retrieved December 28, 2012.
  6. ^ "Hydro-Québec mulls Gentilly 2 recommissioning : Corporate - World Nuclear News".
  7. ^ "Hydro-Québec to keep studying nuclear energy: CEO".
  8. ^ International Atomic Energy Agency (March 23, 2012). "Gentilly-2". Power Reactor Information System. Retrieved 2012-12-14.
  9. ^ "Quebec to spend $1.9B on lone nuclear power plant". CBC.ca. 2008-08-19. Retrieved 2008-08-19.
  10. ^ "Hydro-Québec confirms Gentilly-2 closure at the end of 2012" (Press release). Hydro-Québec. October 3, 2012. Retrieved October 12, 2012.
  11. ^ CBC News (3 October 2012). "Quebec nuclear reactor shutdown will cost $1.8 billion". Canadian Broadcasting Corporation. Retrieved 4 October 2012.
  12. ^ Hydro-Québec. "Thermal generating stations". Retrieved 2012-03-24.
  13. ^ Vincent Broussea-Pouliot (1 September 2012). "Les enjeux oubliés de la campagne". La Presse (in French). Montreal. Retrieved 2012-09-11.
  14. ^ François Cattapan (5 April 2011). "Partisanerie sur le dos de Gentilly" (in French). Archived from the original on May 14, 2021. Retrieved 2012-09-11.
  15. ^ Ian Anderson (8 December 1977). "Quebec Reprieves Heavy Water Plant". The Gazette. Montreal. Retrieved 2012-09-11.