CANDU Lifetime Performance

Operating CANDU Reactors to September 30, 2009

CANDU Lifetime Performance

Lifetime capacity is the total energy produced by the reactor, divided by the energy that could have been produced if the reactor had run at full power, from first being declared in service to the present.   This time span includes any downtime for maintenance outages, mothballing or refurbishment.   Lifetime performance is equivalent to the fraction of time the reactor has run at full power.   For example, Darlington-1 was declared in service on November 14, 1992, and had generated 116,079,000,000 kWh (gross) of electricity by September 30, 2009.   If it had operated at full power for the entire period (imagine running your car at highway speed for the same fraction of time), it would have generated 138,339,000,000 kWh.   The ratio of the two numbers is 0.839, or a lifetime capacity of 83.9%.   The lifetime capacity does not necessarily reflect recent performance.   For instance, Darlington-1 attained 93.8% in 1999, 81.9% in 2000, 91.3% in 2001, 85.4% in 2002, 85.7% in 2003, 72.8% in 2004, 96.0% in 2005, 83.2% in 2006, 96.6% in 2007 and 79.6% in 2008.

The total nuclear-generated electricity delivered to Canadian electrical grids (i.e., net production), since the first CANDU was connected to the grid on June 4, 1962, is approximately 2,352,000,000,000 kWh to September 30, 2009.   Thatís enough to supply a typical Ontario home's electricity needs (10,320 kWh/year), for about 228 million years [1].   Or equivalent to 3.93 years of Canada's annual electricity production (598,841,123 kWh in 2008 [2]).   Note that the amount produced does not include the electricity generated during the testing stages of the reactors prior to them being declared "in-service".

If the nuclear-generated electricity had been generated in coal-fired stations, it would have put about 2.3 billion tonnes of carbon dioxide into the atmosphere, based on an assumption of 0.99 kg of CO2 per kWh of electricity generated by coal.   Or about 1.3 billion tonnes of carbon dioxide into the atmosphere, using natural-gas-fired power plants, based on an assumption of 0.54 kg of CO2 per kWh of electricity generated by natural gas [3].   Canadian nuclear plants primarily replaced additional planned coal-fired stations.

What is the commercial value of the nuclear-generated electricity?   The wholesale price (i.e. from the generating stations themselves) is much lower than the delivered-to-your house retail price.   On May 1, 2002, the Ontario market was deregulated, so the wholesale price now changes depending upon supply and demand.   In the first five years, wholesale spot-market prices reached a maximum of $CDN 1.028 per kWh, and the average price was $CDN 0.0571 per kWh.   Only some of the production is sold at spot market prices, the rest in longer-term contracts, so this does not mean the utilities earned this rate.   It does, however, reflect that electricity prices have risen.

Since April 1 2008, the net wholesale price of nuclear-generated electricity sold by Ontario Power Generation (with 10 of the 18 Canadian power reactors operating and 52% of the operating nuclear capacity) was fixed at $CDN 0.05498 per kWh [4].   If the 2.323 trillion kWh of electricity were produced today, and sold wholesale at $CDN 0.05498/kWh, it would have a value of $CDN 129.3 billion.

In addition, 12 CANDU reactors in operation overseas (Argentina, China, India, Pakistan, Romania and South Korea) have delivered a total of about 619,250,000,000 kWh of electricity to their grids, by September 30, 2009.

There are 9 AECL-designed CANDU 6 reactors in operation, eight of them outside Canada.   In addition, the oldest CANDU 6 (Point Lepreau in New Brunswick) was shut on March 28 2008 for an 18 month major refurbishment (including re-tubing); likewise Korea's Wolsong-1 was shut for refurbishment on April 1, 2009.   The CANDU 6 fleet lifetime capacity factor is weighted towards the older reactors (Point Lepreau, Gentilly-2, Embalse and Wolsong-1 are an average of 26.2 years old since being declared in service, and have an average lifetime capacity factor of 81.1%).    To September 30, 2009, the gross lifetime capacity factor of all 11 CANDU 6 reactors is 84.6%.  


  1. Electricity Choices (Ontario Clean Air Alliance).   Hydro One stated the typical Ontario home consumes 11,283 kWh per year, which means the total lifetime net production of CANDU reactors in Canada, to September 30 2009, would power a typical Ontario home for 208 million years.
  2. International Atomic Energy Agency Power Reactor Information Service (Search by selecting Canada).
  3. Dr. J.T. Rogers, based on Natural Resources Canada data
  4. Ontario Power Generation 2008 Financial Report, Feb 13, 2009.


Updated November 27, 2009

[CNS home page]