The evolution of Canadian research reactors 1942-1992

The ZEEP critical assembly was the first reactor to operate outside the USA. NRX is a heavy-water-moderated high-flux multi-purpose 42 MW reactor with once-through light-water cooling fuelled with HEU-Al-alloy. NRU is a large heavy-water moderated and cooled multipurpose reactor presently fuelled with LEU U2Si-Al to give 115-135 MW. It has a large array of neutron beams for experiments, and is used for isotope production as well as irradiation experiments. The SLOWPOKE reactor has high neutronic efficiency and inherent safety achieved in a low-power (20 kW) research reactor. The MAPLE-X10 reactor under construction at Chalk river will produce isotopes such as Mo-99, and also transmutation-doped silicon. It has a compact light-water-cooled and moderated core surrounded by a heavy-water reflector tank; it uses LEU fuel. Since MAPLE-X10 will not be suitable to replace NRU as the national irradiation-research facility, a MAPLE-MTR (Materials Test Reactor) is planned