SLOWPOKE reactor

Last updated
SLOWPOKE reactor
Slowpoke Reactor Montreal.jpg
Polytechnique Montreal's SLOWPOKE-2 reactor pit cover.
GenerationNeutron
Reactor conceptLow-energy, tank-in-pool type nuclear research reactor
Main parameters of the reactor core
Fuel (fissile material)Information missing
Primary coolantLight-water
Reactor usage
Primary useNeutron activation analysis

The SLOWPOKE (acronym for Safe LOW-POwer Kritical Experiment) is a family of low-energy, tank-in-pool type nuclear research reactors designed by Atomic Energy of Canada Limited (AECL) beginning in the late 1960s. John W. Hilborn (born 1926 or 1927 [1] ) is the scientist most closely associated with their design. [2] They are beryllium-reflected with a very low critical mass, but provide neutron fluxes higher than available from a small particle accelerator or other radioactive sources.

Contents

Basic design

SLOWPOKE reactor core model. Slowpoke Reactor Core Model Montreal.jpg
SLOWPOKE reactor core model.

The SLOWPOKE-2 reactors (most numerous of SLOWPOKE-family reactors) originally used 93% highly enriched uranium in the form of 28% uranium-aluminium alloy with aluminium cladding, and then in 1985 a new low enriched uranium design (~19.9 % enriched) was commissioned using ceramic UO2 fuel. The core is an assembly of about 200-300 fuel pins, only 22 centimetres (8.7 in) diameter and 23 centimetres (9.1 in) high, surrounded by a fixed beryllium annulus and a bottom beryllium slab. Criticality is maintained as the fuel burns up 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 metres (8 ft 2 in) diameter by 6 metres (20 ft) 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

SLOWPOKE-1 and SLOWPOKE-2

The SLOWPOKE research reactor was conceived in 1967 at the Whiteshell Laboratories of AECL. In 1970 a prototype unit called SLOWPOKE (both the name of the reactor and of the prototype reactor class of 2 reactors it was a member of; especially later when further generations of SLOWPOKE reactors had appeared, these type of reactors were named SLOWPOKE-1), 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 reactor was dismantled in 1976 and replaced in University of Toronto by a next generation SLOWPOKE-2 reactor.

The first commercial example started construction in 1970 and was started up 14 May 1971 at AECL's Commercial Products Division in Tunney's Pasture - 20 Goldenrod Driveway, Ottawa, Ontario. It had a power output of 20 kW (thermal) and it was of the SLOWPOKE/SLOWPOKE-1 type. The reactor was a prototype and was shut down 1984.

Two reactors of SLOWPOKE aka SLOWPOKE-1 type were built. Both reactors have been decommissioned.

In 1976 a next generation commercial design, named SLOWPOKE-2 (again both the name of the reactor and reactor class, further members of which were constructed elsewhere), was installed at the University of Toronto, replacing the original SLOWPOKE-1 unit (see above). The commercial model has five sample sites in the beryllium reflector and five sites stationed outside the reflector.

Between 1976 and 1985, further 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 five SLOWPOKE-2 reactors have been decommissioned (Saskatchewan Research Council, University of Toronto, University of Alberta, Dalhousie University, and AECL/MDS Nordion reactor in Kanata), and three converted to LEU (Polytechnique Montreal , University of the West Indies and Royal Military College of Canada ).

All in all, eight SLOWPOKE-2 reactors were built, seven in Canada and one in Jamaica. [3] As of 2022, of the eight, three are operational (the ones using/converted for LEU) and five have been decommissioned.

SLOWPOKE-3 and SLOWPOKE-4

AECL also designed and built (start of construction 1985, start of operation 1987) 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. However, the market for this technology did not materialize, and the proposed SES-10 (SLOWPOKE-4 based on SDR experience) was never built, and the SDR shutdown for decommissioning in 1989.

Marine Power Source

During the mid-1980s Canada briefly considered converting its Oberon class submarines to nuclear power using a SLOWPOKE nuclear reactor to continuously recharge the ship's batteries during submerged operations. [4] A good deal of work had been done on potential marine applications of the reactor at Royal Military College of Canada. [5]

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 (only at the Royal Military College of Canada), and the production of radioactive tracers. 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%.

Three 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.

Former applications

Two of the SLOWPOKE/SLOWPOKE-1 reactors (out of 2 built), five of the SLOWPOKE-2 reactors (out of 8 built) and the single SLOWPOKE-3 reactor (out of 1 built) have been decommissioned. No SLOWPOKE-4 reactor was ever built.

See also

Related Research Articles

<span class="mw-page-title-main">CANDU reactor</span> Canadian heavy water nuclear reactor design

The CANDU is a Canadian pressurized heavy-water reactor design used to generate electric power. The acronym refers to its deuterium oxide moderator and its use of uranium fuel. CANDU reactors were first developed in the late 1950s and 1960s by a partnership between Atomic Energy of Canada Limited (AECL), the Hydro-Electric Power Commission of Ontario, Canadian General Electric, and other companies.

<span class="mw-page-title-main">Nuclear reactor</span> Device used to initiate and control a nuclear chain reaction

A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid, which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of 2022, the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world.

Enriched uranium is a type of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Naturally-occurring uranium is composed of three major isotopes: uranium-238, uranium-235, and uranium-234. 235U is the only nuclide existing in nature that is fissile with thermal neutrons.

<span class="mw-page-title-main">Chalk River Laboratories</span> Nuclear research facility located near Chalk River, Canada

Chalk River Laboratories is a Canadian nuclear research facility in Deep River, about 180 km (110 mi) north-west of Ottawa.

<span class="mw-page-title-main">Fast-neutron reactor</span> Nuclear reactor where fast neutrons maintain a fission chain reaction

A fast-neutron reactor (FNR) or fast-spectrum reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons, as opposed to slow thermal neutrons used in thermal-neutron reactors. Such a fast reactor needs no neutron moderator, but requires fuel that is relatively rich in fissile material when compared to that required for a thermal-neutron reactor. Around 20 land based fast reactors have been built, accumulating over 400 reactor years of operation globally. The largest of this was the Superphénix Sodium cooled fast reactor in France that was designed to deliver 1,242 MWe. Fast reactors have been intensely studied since the 1950s, as they provide certain advantages over the existing fleet of water cooled and water moderated reactors. These are:

Atomic Energy of Canada Limited (AECL) is a Canadian federal Crown corporation and Canada's largest nuclear science and technology laboratory. AECL developed the CANDU reactor technology starting in the 1950s, and in October 2011 licensed this technology to Candu Energy.

<span class="mw-page-title-main">High Flux Australian Reactor</span> Australias first nuclear reactor

The High Flux Australian Reactor (HIFAR) was Australia's first nuclear reactor. It was built at the Australian Atomic Energy Commission Research Establishment at Lucas Heights, Sydney. The reactor was in operation between 1958 and 2007, when it was superseded by the Open-pool Australian lightwater reactor, also in Lucas Heights.

<span class="mw-page-title-main">Research reactor</span> Nuclear device not intended for power or weapons

Research reactors are nuclear fission-based nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritime propulsion.

The National Research Universal (NRU) reactor was a 135 MW nuclear research reactor built in the Chalk River Laboratories, Ontario, one of Canada’s national science facilities. It was a multipurpose science facility that served three main roles. It generated radionuclides used to treat or diagnose over 20 million people in 80 countries every year. It was the neutron source for the NRC Canadian Neutron Beam Centre: a materials research centre that grew from the Nobel Prize-winning work of Bertram Brockhouse. It was the test bed for Atomic Energy of Canada Limited to develop fuels and materials for the CANDU reactor. At the time of its retirement on March 31, 2018, it was the world's oldest operating nuclear reactor.

The Whiteshell Laboratories, originally known as the Whiteshell Nuclear Research Establishment (WNRE) was an Atomic Energy of Canada (AECL) laboratory in Manitoba, northeast of Winnipeg. It was originally built as a home for the experimental WR-1 reactor, but over time came to host a variety of experimental systems, including a SLOWPOKE reactor and the Underground Research Laboratory to study nuclear waste disposal. Employment peaked in the early 1970s at about 1,300, but during the 1980s the experiments began to wind down, and in 2003 the decision was made to close the site. As of 2017 the site is undergoing decommissioning with a planned completion date in 2024. The decommissioning process for WR-1 involves transporting low-level nuclear waste to another Canadian Nuclear Laboratories (CNL) research site, Chalk River Laboratories in Ottawa for containment, and encasing the reactor in concrete. The details of this process continue to be criticized, evaluated, and revised.

The Chinese built Miniature Neutron Source reactor (MNSR) is a small and compact research reactor modeled on the Canadian HEU SLOWPOKE-2 design.

The Advanced CANDU reactor (ACR), or ACR-1000, was a proposed Generation III+ nuclear reactor design, developed by Atomic Energy of Canada Limited (AECL). It combined features of the existing CANDU pressurised heavy water reactors (PHWR) with features of light-water cooled pressurized water reactors (PWR). From CANDU, it took the heavy water moderator, which gave the design an improved neutron economy that allowed it to burn a variety of fuels. It replaced the heavy water cooling loop with one containing conventional light water, reducing costs. The name refers to its design power in the 1,000 MWe class, with the baseline around 1,200 MWe.

<span class="mw-page-title-main">Swimming pool reactor</span> Type of nuclear reactor

A swimming pool reactor, also called an open pool reactor, is a type of nuclear reactor that has a core immersed in an open pool usually of water.

The Whiteshell Reactor No. 1, or WR-1, was a Canadian research reactor located at AECL's Whiteshell Laboratories (WNRL) in Manitoba. Originally known as Organic-Cooled Deuterium-Reactor Experiment (OCDRE), it was built to test the concept of a CANDU-type reactor that replaced the heavy water coolant with an oil substance. This had a number of potential advantages in terms of cost and efficiency.

<span class="mw-page-title-main">UF Training Reactor</span>

The University of Florida Training Reactor (UFTR), commissioned in 1959, is a 100 kW modified Argonaut-type reactor at the University of Florida in Gainesville, Florida. It is a light water and graphite moderated, graphite reflected, light water cooled reactor designed and used primarily for training and nuclear research related activities. The reactor is licensed by the Nuclear Regulatory Commission and is the only research reactor in Florida.

<span class="mw-page-title-main">Maria reactor</span>

The Maria reactor is Poland's second nuclear research reactor and is the only one still in use. It is located at Narodowe Centrum Badań Jądrowych (NCBJ) at Świerk-Otwock, near Warsaw and named in honor of Maria Skłodowska-Curie. It is the only reactor of Polish design.

<span class="mw-page-title-main">Nuclear industry in Canada</span>

Nuclear industry in Canada is an active business and research sector, producing about 15% of its electricity in nuclear power plants of domestic design. Canada is the world's largest exporter of uranium, and has the world's second largest proven reserves. Canada also exports nuclear technology within the terms of the Nuclear Non-proliferation Treaty, to which it is a signatory, and is the world's largest producer of radioactive medical isotopes.

<span class="mw-page-title-main">Pakistan Atomic Research Reactor</span> Pair of research nuclear reactors in Nilore, Islamabad, Pakistan

The Pakistan Atomic Research Reactor or (PARR) are two nuclear research reactors and two other experimental neutron sources located in the PINSTECH Laboratory, Nilore, Islamabad, Pakistan.

The Ghana Research Reactor-1 (GHARR-1) is a nuclear research reactor located in Accra, Ghana and is the only nuclear reactor in the country. It is operated by the National Nuclear Research Institute, a sub-division of the Ghana Atomic Energy Commission. The reactor is a commercial version of the Chinese Miniature Neutron Source Reactor (MNSR) design. The reactor had its first criticality on December 17, 1994.

<span class="mw-page-title-main">Organic nuclear reactor</span> Nuclear reactor that uses organic liquids for cooling and neutron moderation

An organic nuclear reactor, or organic cooled reactor (OCR), is a type of nuclear reactor that uses some form of organic fluid, typically a hydrocarbon substance like polychlorinated biphenyl (PCB), for cooling and sometimes as a neutron moderator as well.

References

  1. "Retired physicist fights to keep Chalk River's historic research facility open".
  2. "Dr. John W. Hilborn".
  3. "SLOWPOKE Nuclear Reactors in Canada". 4 March 2016.
  4. Julie H. Ferguson (10 March 2014). Through a Canadian Periscope: The Story of the Canadian Submarine Service. Dundurn. p. 363. ISBN   978-1-4597-1056-6.
  5. Dunlop, David. "A Canadian Hybrid Submarine Design: A Case for the Slowpoke-2 Reactor". Canadian Naval Review. Canadian Naval Review. Retrieved 4 April 2024.
  6. "Nuclear facility – Royal Military College of Canada SLOWPOKE-2 research reactor". nuclearsafety.gc.ca. Canadian Nuclear Safety Commission. 2014-02-03. Retrieved 2023-09-09.
  7. Royal Military College of Canada SLOWPOKE
  8. "École Polytechnique de Montréal's SLOWPOKE-2" (PDF). Archived from the original (PDF) on 2013-10-16. Retrieved 2013-07-08.
  9. Dalhousie University SLOWPOKE-2
  10. University of Toronto SLOWPOKE-2
  11. "University of Alberta Public Information and Disclosure program". Archived from the original on 2019-12-14. Retrieved 2017-03-12.
  12. "University of Alberta's SLOWPOKE-2". Archived from the original on 2013-10-12. Retrieved 2013-07-08.
  13. Shield, David (4 January 2019). "'It was very unique': Saskatoon's SLOWPOKE-2 research reactor shutting down after 37 years". Canadian Broadcasting Corporation. Retrieved 29 November 2019.