Higher energy yields using thorium as the fuel ( of thorium produces the same amount of energy as tons of uranium) also makes it more attractive. OMERS has also shown interest in the company. History 1940s AECL traces its heritage to the Second World War when a joint Canadian-British nuclear research laboratory, the Montreal Laboratory, was established in Montreal in 1942, under the National Research Council of Canada to develop a design for a nuclear reactor. Canadian firms had American contracts from the Manhattan Project; with Eldorado Gold Mines for mining and processing uranium ore and with by Consolidated Mining and Smelting (CMS) for a heavy water plant at Trail, British Columbia. In 1944, approval was given by the federal government to begin with construction of the ZEEP (Zero Energy Experimental Pile) reactor at the Chalk River Nuclear Laboratories near Chalk River, Ontario, located on the Ottawa River approximately 190 km northwest of Ottawa. AECL was also involved in the development of associated technology such as the UTEC computer. On September 5, 1945, the ZEEP reactor first went critical, achieving the first "self-sustained nuclear reaction outside the United States". ZEEP put Canada at the forefront of nuclear research in the world and was the instigator behind eventual development of the CANDU reactors, ZEEP having operated as a research reactor until the early 1970s. In 1946 the Montreal research laboratory was closed and research was consolidated at Chalk River Laboratories. On July 22, 1947, the NRX (National Research Experimental) reactor, the most powerful reactor in the world at the time, went critical and was "used successfully for producing radioisotopes, undertaking fuels and materials development work for CANDU reactors, and providing neutrons for physics experiments". 1950s In 1952 AECL was formed by the government with a mandate to develop peaceful uses of nuclear energy. On December 12, 1952, one of the world's first major reactor accidents occurred in the NRX reactor at AECL's Chalk River Laboratories, when a combination of human and mechanical error led to a temporary loss of control over the reactor's power level. Undercooling of the fuel channels led to a partial meltdown. This caused a hydrogen-oxygen explosion inside the calandria. Several fuel bundles experienced melting and ruptured, rendering much of the core interior unusable. The reactor building was contaminated, as well as an area of the Chalk River site, and millions of gallons of radioactive water accumulated in