| 1941 | | George C. Laurence builds one of the world’s first nuclear reactors at the National Research Council laboratories in Ottawa. |
| 1944 | | National Research Council builds nuclear research facility at Chalk River, Ontario. |
| 1945 | | Canada becomes the second country to control nuclear fission in a reactor – the ZEEP (zero energy experimental pile) at Chalk River. |
| 1952 | | Atomic Energy of Canada Ltd. (AECL) is created to develop peaceful uses of nuclear energy. |
| 1954 | | Wilfrid B. Lewis initiates the development of the CANDU reactor through cooperation between AECL, Ontario Hydro and Canadian General Electric Company. |
| 1962 | | The NPD (Nuclear Power Demonstration) reactor – Canada’s first electricity-producing reactor – comes online feeding power to the Canadian electricity grid for the first time. The 20 MWe reactor successfully demonstrates the feasibility of the CANDU concept with on-power refuelling and heavy water moderator and coolant. |
| 1968 | | The Douglas Point facility – Canada’s first full-scale nuclear generating station – comes online. Operated by Ontario Hydro, the reactor uses the CANDU design. |
| 1971 | | The first CANDU reactor begins commercial operation (at Pickering A Unit 1) in Ontario. It produces more electricity than any other nuclear power facility at the time. |
| 1983 | | In Canada, Point Lepreau and Gentilly-2 begin commercial operation. Two more CANDU 6 units in Argentina and Korea begin commercial operation this year as well. CANDU reactors hold seven of the top 10 places for lifetime performance. |
| 1984-1987 | | Four 915 MWe reactor units begin operation at Ontario Hydro’s Bruce B site. |
| 1987 | | The CANDU reactor is ranked as one of Canada’s top 10 engineering achievements of the century in celebrations marking Canada's engineering centennial. |
| 1993 | | With final (of four) Darlington units in operation, Canada has 22 nuclear power reactors in Ontario, Quebec and New Brunswick. |
| 1996 | | Two CANDU reactors are sold to China in what is the largest commercial contract between China and Canada in the 20th century. |
| 1996 | | Romania’s Cernavoda 1 station begins commercial operation. |
| 1996 | | Bruce Unit 3 becomes the first CANDU reactor in the world to reach 100 million MWh of lifetime gross energy production, which is enough to supply a city the size of Thunder Bay for 90 years. |
| 1997-1998 | | Korea's Wolsong 2 and 3 units begin commercial operation. |
| 2001 | | First tests of mixed oxide fuel (MOX) underway at Chalk River. |
| 2002 | | China's Qinshan III unit reaches full power. |
| 2003 | | Two CANDU units in China are delivered under budget and four months ahead of schedule, which is the fastest construction of a nuclear power facility in China. |
| 2008 | | New Brunswick Power begins refurbishing the Point Lepreau generating station. |
| 2008 | | Hydro-Quebec announces the refurbishment of the G2 reactor in Becancour. |
| 2009 | | KHNP begins retubing the Wolsong 1 generating station. |
| 2010 | | Nuclear energy generates over 58% of Ontario's total electricity. |
| 2011 | | Wolsong 1 returns to the grid after a successful retube project extends the life of the station by up to 30 years. |
| 2011 | | Candu Energy Inc. is created. |