The CANDU development effort has gone through four major stages over time. The first systems were experimental and prototype machines of limited power. These were replaced by a second generation of machines of 500 to 600 MWe (the CANDU 6), a series of larger machines of 900 MWe, and finally developing into the CANDU 9 and ACR-1000 effort.V. G. Snell, "CANDU Safety, #1 – CANDU Nuclear Power Plant Design" , AECL, 24 May 2001."CANDU Evolution" , AECL.
The CANDU development effort has gone through four major stages over time. The first systems were experimental and prototype machines of limited power. These were replaced by a second generation of machines of 500 to 600 MWe (the CANDU 6) a series of larger machines of 900 MWe, and finally developing into the CANDU 9 and ACR-1000 e,ffort.V. G. Snell, "CANDU Safety, #1 – CANDU Nuclear Power Plant Design" , AECL, 24 May 2001."CANDU Evolution" , AECL.