Nuclear Power Demonstration, Canada's first power reactor (22 MWe gross), started for the first time (i.e. first criticality) at 02:40 April 11 1962. NPD was essentially the first CANDU reactor - heavy water-moderated and cooled, horizontal fuel channels, fuelling on-line, natural uranium fuel in 0.5 m long bundles. The reactor ran successfully as a demonstration/research & development/training unit until 1987, some 15 years longer than its original design life.
Details can be found on the Canadian Nuclear Society web site at http://www.cns-snc.ca/events/npd/npd_eng.htm ou en francais a http://www.cns-snc.ca/events/npd/npd_fr.htm