SLOWPOKE reactor 2807861 223321004 2008-07-03T15:35:52Z 137.94.113.153 /* Current applications */ Changed an internal link from neutron to neutron activation analysis The '''SLOWPOKE''' (acronym for Safe Low-Power Kritical Experiment) is a low-energy, [[Pool-type reactor|pool-type]] [[Research reactor|nuclear research reactor]] designed by [[Atomic Energy of Canada Limited]] (AECL) in the late [[1960]]s. It is beryllium-[[neutron reflector|reflected]] with a very low [[Critical mass (nuclear)|critical mass]] but provides [[neutron flux]]es higher than available from a small [[particle accelerator]] or other [[Neutron source|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 rod|fuel pins]], only 22 cm diameter and 23 cm high, surrounded by a fixed [[beryllium]] annulus and a bottom beryllium slab. [[Critical mass|Criticality]] is maintained by adding [[beryllium]] plates in a tray on top of the core. The [[Nuclear reactor core|reactor core]] sits in a pool of regular light-water, 2.5 m diameter by 6 m deep, which provides [[coolant|cooling]] via natural convection. In addition to passive cooling, the reactor has a high degree of [[Passively safe|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 [[Void coefficient|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]]. 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 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 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 [[Enriched uranium|Highly Enriched Uranium]] (HEU) fuel were commissioned in six Canadian cities and in [[Kingston, Jamaica|Kingston]], [[Jamaica]]. In [[1985]] the first [[enriched uranium|Low-Enriched Uranium]] (LEU) fuelled SLOWPOKE-2 reactor was commissioned at the [[Royal Military College of Canada]] (RMC) in [[Kingston, Ontario|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. ===Autonomous Marine Power Source (AMPS)=== During the early 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]]. Another project by a Canada-France consortium, International Submarine Transportation Systems (ISTS) would have powered the world’s first commercial nuclear submarine with a 1.5Mw SLOWPOKE-type of reactor designed by Energy Conversion Systems Inc. This unit would provide the heat to power a [[Stirling engine]]. They got as far as building the craft, known as the SAGA-N, before the project collapsed in a tax dispute between Canada and France over funding. == 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 RMC) 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%. Six of the original reactors are still in operation and one has been refuelled. 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. ==References== *<div id="Whitlock">Whitlock:{{cite web| url=http://www.nuclearfaq.ca|title=Canadian Nuclear FAQ| work=The Canadian Nuclear FAQ by Dr. Jeremy Whitlock|accessdate=March 5|accessyear=2005}} </div> *<div id="G. Kennedy and J. St. Pierre">G. Kennedy and J. St. Pierre::{{cite web| url=http://www.rertr.anl.gov/Web2002/2003_20Web/Full_20Papers-PDF/Kennedy.pdf|title=LEU-FUELLED SLOWPOKE-2 RESEARCH REACTORS: OPERATIONAL EXPERIENCE AND UTILISATION| work=2002 International Meeting on Reduced Enrichment for Research and Test Reactors|accessdate=October 01|accessyear=2005}} *[http://www.cns-snc.ca/branches/quebec/saga_n/SAGA_N.html La mort du projet SAGA-N par impôts fédéraux] ''The death of the SAGA-N project by federal tax'' (English translation provided) *[http://www.sfu.ca/casr/ft-winz1.htm Taking the Plunge: Should Canada Use Fuel Cell Technology to make the Victoria-class Submarines more Stealthy?] == See also== *[[Nuclear reactor]] *[[Nuclear fission]] ==External links== *[http://chem-eng.toronto.edu/~slopoke/ SLOWPOKE Reactor Facility of the University of Toronto] *[http://www.ualberta.ca/~slowpoke/ University of Alberta SLOWPOKE Nuclear Reactor Facility] *[http://www2.polymtl.ca/nucl/LTN/SLP-En.html The SLOWPOKE Laboratory École Polytechnique] *[http://www.science.mcmaster.ca/mnr/Main-Page/Frameset-homepage.htm McMaster Nuclear Reactor] *[http://web.archive.org/web/20060707105617/http://www.rmc.ca/academic/registrar/programme/cal-poke_e.htm Royal Military College of Canada SLOWPOKE-2 Nuclear Reactor and Facility] *[http://www.src.sk.ca/html/labs_facilities/analytical_labs/radiochem_slowpoke/index.cfm Saskatchewan Research Council Analytical Laboratories] *[http://chemistry.dal.ca/Research/Centres_and_Facilities/SLOWPOKE.php Dalhousie University Department of Chemistry SLOWPOKE Nuclear Research Reactor] *[http://www.aecl.ca/ Atomic Energy of Canada Limited] *[http://www.nuclearsafety.gc.ca/ Canadian Nuclear Safety Commission] *[http://www.cns-snc.ca/ Canadian Nuclear Society] *[http://www.cna.ca/ Canadian Nuclear Association] *[http://www.icens.org/ International Centre for Environmental and Nuclear Sciences, Jamaica] {{DEFAULTSORT:Slowpoke reactor}} [[Category:Atomic Energy of Canada Limited]] [[Category:Nuclear research reactors]] [[Category:Science and technology in Canada]]