 Since then five reactors have been decommissioned (Saskatchewan Research Council, University of Toronto, Alberta, Dalhousie, and Saskatchewan), and one converted to LEU (Polytechnique Montreal).AECL also designed and built a scaled-up version (2-10 MWth) called the SLOWPOKE Demonstration Reactor (SDR, "SLOWPOKE-3") for district heating at its Whiteshell Nuclear Research Establishment in Manitoba.The economics of a district-heating system based on SDR technology were estimated to be competitive with that of conventional fossil fuels.