SLOWPOKE reactor The SLOWPOKE ( acronym for Safe LOW - POwer Kritical Experiment ) is a low - energy , pool - type nuclear research reactor designed by Atomic Energy of Canada Limited ( AECL ) in the late 1960s . John W . Hilborn ( now retired from AECL ) is the scientist most closely associated with its design . It is beryllium - reflected with a very low critical mass but provides neutron flux es higher than available from a small particle accelerator or other radioactive sources . Basic design . The SLOWPOKE - 2 uses 93 % ( originally ) enriched uranium in the form of 28 % uranium - aluminum alloy with aluminum cladding . The core is an assembly of about 300 fuel pins , only 22 cm diameter and 23 cm high , surrounded by a fixed beryllium annulus and a bottom beryllium slab . Criticality is maintained by adding beryllium plates in a tray on top of the core . The reactor core sits in a pool of regular light - water , 2 . 5 m diameter by 6 m deep , which provides cooling via natural convection . In addition to passive cooling , the reactor has a high degree of inherent safety ; that is , it can regulate itself through passive , natural means , such as the chain reaction slowing down if the water heats up or forms bubbles . These characteristics are so dominant , in fact , that the SLOWPOKE - 2 reactor is licensed to operate unattended overnight ( but monitored remotely ) . Most SLOWPOKES are rated at a nominal 20 kW , although operation at higher power for shorter durations is possible . History . The SLOWPOKE research reactor was conceived in 1967 at the Whiteshell Laboratories of AECL . In 1970 a prototype unit was designed and built at Chalk River Laboratories . It was primarily intended for Canadian universities , providing a higher neutron flux than available from small commercial accelerators , while avoiding the complexity and high operating costs of existing nuclear reactors . The Chalk River prototype went critical in 1970 , and was moved to the University of Toronto in 1971 . It had one sample site in the beryllium reflector and operated at a power level of 5 kW . In 1973 the power was increased to 20 kW and the period of unattended operation was increased from 4 hours to 18 hours . The first commercial example was started up in 1971 at AECL ' s Commercial Products Division in Ottawa ; and in 1976 a commercial design , named SLOWPOKE - 2 , was installed at the University of Toronto , replacing the original SLOWPOKE - 1 unit . The commercial model has five sample sites in the beryllium reflector and five sites stationed outside the reflector . Between 1976 and 1984 , seven SLOWPOKE - 2 reactors with Highly Enriched Uranium ( HEU ) fuel were commissioned in six Canadian cities and in Kingston , Jamaica . In 1985 the first Low - Enriched Uranium ( LEU ) fuelled SLOWPOKE - 2 reactor was commissioned at the Royal Military College of Canada ( RMC ) in Kingston , Ontario . Since then several units have been converted to LEU . AECL also designed and built a scaled - up version ( 2 - 10 MWth ) called SLOWPOKE - 3 for district heating at its Whiteshell Nuclear Research Establishment in Manitoba . The economics of a district - heating system based on SLOWPOKE - 3 technology were estimated to be competitive with that of conventional fossil fuel s . However , the market for this technology did not materialize . A Chinese version of the Slowpoke exists , designated the Miniature Neutron Source Reactor ( MNSR ) . This version is nominally rated at 27 kW with similar characteristics and performance . Marine Power Source . During the mid - 1980s Canada briefly considered converting its Oberon class submarine s to nuclear power using a SLOWPOKE nuclear reactor to continuously recharge the ship ' s batteries during submerged operations . A good deal of work had been done on potential marine applications of the reactor at Royal Military College of Canada . Current applications . SLOWPOKE reactors are used mainly for neutron activation analysis ( NAA ) , in research and as a commercial service , but also for teaching , training , irradiation studies , neutron radiography ( at the Royal Military College of Canada , École Polytechnique de Montréal and University of Alberta ) and the production of radioactive tracer s . The main advantages are the reliability and ease of use of this design of reactor and the reproducibility of the neutron flux . Since the fuel is not modified at all for at least 20 years , the neutron spectrum in the irradiation sites does not change and the neutron flux is reproducible to about 1 % . Four of the original reactors are still in operation . Although all of the technical goals of this reactor were achieved , the lack of foreign sales was disappointing , the market being taken by the Chinese version .