History and Evolution

AECL-Designed Research Reactors
Since the start up of our first research reactor in 1945, AECL has designed, developed and built 17 research reactors around the world. 

1945 - ZEEP (Zero Energy Experimental Pile)
In 1945, this 10-watt research reactor achieved the first controlled nuclear chain reaction outside the United States. Built at AECL's laboratories at Chalk River, Ontario, it also provided valuable information on the characteristics of heavy-water-moderated fuel lattices for the reactors to come, including early CANDU commercial power reactors. ZEEP was retired from service in 1970. Visit ZEEP's new home: The Canada Museum of Science and Technology

1947 - NRX (National Research Experimental)
This 42 MWt research reactor achieved criticality in 1947 and generated the highest neutron flux available anywhere at the time. NRX, which was shut down in 1992, was operated by AECL to develop fuels, materials and nuclear components for power reactors, to produce radioisotopes for medicine and industry, and to generate neutron beams for basic and applied research. Reactors of the NRX design were supplied on a turnkey basis to India in 1960 and Taiwan in 1969.

1957 - PTR (Pool Test Reactor)
This 10 kWt pool-type reactor was built at Chalk River in 1957. It used 93% enriched uranium-aluminum plate-type fuel. The reactor, which was retired from service in 1990, was used for burn up measurement of fissile samples from NRX.

1957 - NRU (National Research Universal)
Designed as a 200 MWt reactor, NRU began operating in 1957, and is still one of the world's best-performing research reactors. It produces a high percentage of the world's medical and industrial radioisotopes, including molybdenum-99, a critical isotope used for medical diagnoses. NRU's large irradiation space has been an important factor in the testing of fuel bundles and fuel-channel components for CANDU reactors. NRU is used for research into reactor fuels, materials and components, and is the centre for neutron beam research in Canada. Originally designed for operation with natural uranium, NRU was converted to high-enriched uranium in 1964. AECL has been operating NRU with low-enriched uranium (LEU) fuel since 1991.

1960 - ZED-2 (Zero Energy Deuterium-2)
This larger version of ZEEP started up in 1960 to facilitate measurements on larger, more representative CANDU lattices. It has also been used for definitive studies of the effects of heavy water and alternative light water and organic coolants. The reactor is still operating at Chalk River where it is used for reactor physics research.

1965 - WR-1 (Whiteshell Reactor-1)
The central experimental facility at AECL's Whiteshell Laboratories in Manitoba, Canada from 1965 to 1985, the WR-1 featured the first AECL-designed calandria fabricated from stainless steel. It also demonstrated the feasibility of an organic-cooled CANDU power reactor.

1968 - SLOWPOKE-2 (Safe Low Power Critical Experiment)
The prototype of this 20 kWt reactor was tested in the PTR pool at Chalk River from 1968-1970. It was designed for neutron activation analysis, trace radioisotope production and as a tool for teaching nuclear science and engineering. It is the only reactor considered safe enough to be licensed for unattended operation. Eight SLOWPOKE reactors have been supplied to universities and research centres across Canada and in Jamaica. Six remain in operation.

1995 - HANARO
MAPLE's core design technology was incorporated into the Korea Atomic Energy Research Institute's (KAERI's) 30 MWt HANARO multi-purpose research reactor, which started up in 1995. It has capabilities for fuel and materials testing, neutron beam experiments, isotope production, silicon irradiation and neutron radiography.