Chalk River Laboratories

Chalk River Laboratories (French: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories) is a Canadian nuclear research facility near Chalk River, about 180 km (110 mi) north-west of Ottawa.

CRL is a site of major research and development to support and advance nuclear technology, in particular CANDU reactor technology. CRL has expertise in physics, metallurgy, chemistry, biology, and engineering, and hosts unique research facilities. For example, Bertram Brockhouse, a professor at McMaster University, received the 1994 Nobel Prize in Physics for his pioneering work in neutron spectroscopy while at CRL from 1950 to 1962. Sir John Cockcroft was an early director of CRL and also a Nobel laureate. CRL produces a large share of the world's supply of medical radioisotopes.[1] It is owned by the Canadian Nuclear Laboratories subsidiary of Atomic Energy of Canada Limited and operated under contract by the Canadian National Energy Alliance, a private-sector consortium led by SNC-Lavalin.[2]

Chalk River Laboratories
Chalk River Laboratories
Chalk River Laboratories seen from the Ottawa River
Research typeApplied
Field of research
Nuclear physics
Address286 Plant Road
LocationChalk River, Ontario, Canada
46°03′01″N 77°21′40″W / 46.050242°N 77.361002°WCoordinates: 46°03′01″N 77°21′40″W / 46.050242°N 77.361002°W
Campus3,700 ha (9,100 acres)
AffiliationsAtomic Energy of Canada Limited, Canadian Nuclear Laboratories
Operating agency
Canadian National Energy Alliance


NRX Pile Building and ZEEP Building- Cooling Tanks 1945
NRX and Zeep buildings, Chalk River Laboratories, 1945

The facility arose out of a 1942 collaboration between British and Canadian nuclear researchers which saw a Montreal research laboratory established under the National Research Council (NRC). By 1944 the Chalk River Laboratories were opened and in September, 1945 the facility saw the first nuclear reactor outside of the United States become operational (see Lew Kowarski). In 1946, NRC closed the Montreal laboratory and focused its resources on Chalk River.

In 1952, Atomic Energy of Canada Limited (AECL) was created by the government to promote peaceful use of nuclear energy. AECL also took over operation of Chalk River from the NRC. Since the 1950s various nuclear research reactors have been operated by AECL for production of nuclear material for medical and scientific applications. The Laboratories produce about one-third of the world's medical isotopes, and about half of the North American supply. Despite the declaration of peaceful use, from 1955 to 1976, Chalk River facilities supplied about 250 kg of plutonium, in the form of spent reactor fuel, to the U.S. Department of Energy to be used in the production of nuclear weapons.[3] (The bomb dropped on Nagasaki, Japan, used about 6.4 kg of plutonium.)

Canada's first nuclear power plant, a partnership between AECL and Hydro-Electric Power Commission of Ontario, went online in 1962 near the site of Chalk River Laboratories. This reactor, Nuclear Power Demonstration (NPD), was a demonstration of the CANDU reactor design, one of the world's safest and most successful nuclear reactors.

The Deep River neutron monitor operated once in Chalk river.[4]

1952 NRX incident

Chalk River was also the site of two nuclear accidents in the 1950s. The first incident occurred in 1952, when there was a power excursion and partial loss of coolant in the NRX reactor, which resulted in significant damage to the core. The control rods could not be lowered into the core because of mechanical problems and human errors. Three rods did not reach their destination and were taken out again by accident. The fuel rods were overheated, resulting in a meltdown. The reactor and the reactor building were seriously damaged by hydrogen explosions. The seal of the reactor vessel was blown up four feet. In the cellar of the building, some 4,500 tons of radioactive water was found. This water was dumped in ditches around 1600 meters from the border of the Ottawa River. During this accident some 10,000 curies or 370 TBq of radioactive material was released.[5] Future U.S. president Jimmy Carter, then a U.S. Navy officer, was part of the cleanup crew.[6][7] Two years later the reactor was in use again.[8]

1958 NRU incident

The second accident, in 1958, involved a fuel rupture and fire in the National Research Universal reactor (NRU) reactor building. Some fuel rods were overheated. With a robotic crane, one of the rods with metallic uranium was pulled out of the reactor vessel. When the arm of the crane moved away from the vessel, the uranium caught fire and the rod broke. The largest part of the rod fell down into the containment vessel, still burning. The whole building was contaminated. The valves of the ventilation system were opened, and a large area outside the building was contaminated. The fire was extinguished by scientists and maintenance men in protective clothing running along the hole in the containment vessel with buckets of wet sand, throwing the sand down at the moment they passed the smoking entrance.[9]

Both accidents required a major cleanup effort involving many civilian and military personnel. Follow-up health monitoring of these workers has not revealed any adverse impacts from the two accidents.[10][11] However, the Canadian Coalition for Nuclear Responsibility, an anti-nuclear watchdog group, notes that some cleanup workers who were part of the military contingent assigned to the NRU reactor building unsuccessfully applied for a military disability pension due to health damages.[6]

Chalk River Laboratories remain an AECL facility to this day and are used as both a research (in partnership with the NRC) and production facility (on behalf of AECL) in support of other Canadian electrical utilities.

2007 shutdown

On November 18, 2007, the NRU, which makes medical radioisotopes, was shut down for routine maintenance. This shutdown was extended when AECL, in consultation with the Canadian Nuclear Safety Commission (CNSC), decided to connect seismically-qualified emergency power supplies (EPS) to two of the reactor's cooling pumps (in addition to the AC and DC backup power systems already in place), which had been required as part of its August 2006 operating licence issued by the CNSC. This resulted in a worldwide shortage of radioisotopes for medical treatments because Chalk River makes the majority of the world's supply of medical radioisotopes, including two-thirds of the world's technetium-99m.[12]

On December 11, 2007, the House of Commons of Canada, acting on independent expert advice, passed emergency legislation authorizing the restarting of the NRU reactor and its operation for 120 days (counter to the decision of the CNSC), which was passed by the Senate and received Royal Assent on December 12. Prime Minister Stephen Harper criticized the CNSC for this shutdown which "jeopardized the health and safety of tens of thousands of Canadians", insisting that there was no risk, contrary to the testimony of then CNSC President & CEO Linda Keen. She would later be fired for ignoring a decision by Parliament to restart the reactor, reflecting its policy that the safety of citizens requiring essential nuclear medicine should be taken into account in assessing the overall safety concerns of the reactor's operation.[13][14][15][16][17] The NRU reactor was restarted on December 16, 2007.

2008 radioactive leakage

On December 5, 2008, heavy water containing tritium leaked from the NRU.[18] The leaked water was contained within the facility, and the Canadian Nuclear Safety Commission (CNSC) was notified immediately, as required.

In its formal report to the CNSC, filed on December 9, 2008 (when the volume of leakage was determined to meet the requirement for such a report) AECL mentioned that 47 litres of heavy water were released from the reactor, about 10% of which evaporated and the rest contained, but affirmed that the spill was not serious and did not present a threat to public health.[19] The amount that evaporated to the atmosphere is considered to be minor, accounting for less than a thousandth of the regulatory limit.[20] The public was informed of the shutdown at the reactor, but not the details of the leakage since it was not deemed to pose a risk to the public or environment. The leak stopped before the source could be identified, and the reactor was restarted on December 11, 2008 with the approval of the CNSC, after a strategy for dealing with the leak (should it reappear) was put in place.

In an unrelated incident, the same reactor had been leaking 7,001 litres of light water per day from a crack in a weld of the reactor's reflector system. This water has been systematically collected, purified in an on-site Waste Treatment Centre, and eventually released to the Ottawa River in accordance with CNSC, Health Canada, and Ministry of the Environment regulations. Although the leakage is not a concern to the CNSC from a health, safety or environmental perspective,[21] AECL has plans for a repair to reduce the current leakage rate for operational reasons.

2009 NRU reactor shutdown

In mid-May 2009 the heavy water leak at the base of the NRU reactor vessel, first detected in 2008 (see above), returned at a greater rate and prompted another temporary shutdown that lasted until August 2010. The lengthy shutdown was necessary to first completely defuel the entire reactor, then ascertain the full extent of the corrosion to the vessel, and finally to effect the repairs – all with remote and restricted access from a minimum distance of 8 metres due to the residual radioactive fields in the reactor vessel. The 2009 shutdown occurred at a time when only one of the other four worldwide regular medical isotope sourcing reactors was producing, resulting in a worldwide shortage.

NRU shutdown in March 2018

The NRU reactor licence expired in 2016, however the licence was extended to March 31, 2018.[22] The reactor was shut down for the last time at 7 p.m. on March 31, 2018,[23] and has entered a "state of storage" prior to decommissioning operations which will continue for many years within the scope of future operating or decommissioning licences issued by the CNSC.

Major facilities

  • ZEEP – Zero Energy Experimental Pile Reactor (1945–1973).
  • NRX – NRX Reactor (1947–1992).
  • NRU – National Research Universal 135 MWt Reactor (1957–2018).
    • CNBC – Canadian Neutron Beam Centre
  • PTR – Pool Test 10 kW Reactor (1957–1990).
  • ZED-2 – Zero Energy Deuterium 200W Reactor (1960–).
  • NPD – Nuclear Power Demonstration 20MW(e) reactor; located north of CRL in Rolphton, Ontario (1960–1987).
  • SLOWPOKE – Safe Low-Power Kritical Experiment 5 kW Reactor (1970–1976); moved to the University of Toronto in 1971.
  • TASCC – Tandem Accelerator Superconducting Cyclotron (1986–1996)
  • MAPLE-1 – Multipurpose Applied Physics Lattice Experiment Reactor (2000–2008; canceled).
  • MAPLE-2 – Multipurpose Applied Physics Lattice Experiment Reactor (2003–2008; canceled).
  • CRIPT – Cosmic Ray Inspection and Passive Tomography

See also

Further reading


  1. ^ "Chalk River makes 1st isotopes in 15 months". August 18, 2010. Archived from the original on 6 June 2011. Retrieved 15 March 2011.
  2. ^ Marowits, Ross (June 26, 2015). "SNC-Lavalin consortium chosen to run Chalk River nuclear lab". Ottawa Citizen. Archived from the original on April 15, 2016. Retrieved February 9, 2017.
  3. ^ letter from Dept. of Energy official, March 4, 1996, published at "Archived copy". Archived from the original on 2008-06-28. Retrieved 2008-06-28.CS1 maint: Archived copy as title (link)
  4. ^ "Archived copy". Archived from the original on 2014-11-29. Retrieved 2014-11-22.CS1 maint: Archived copy as title (link)
  5. ^ Canadian Nuclear Society (1989) The NRX Incident by Peter Jedicke
  6. ^ a b "Reactor Accidents: The Human Fallout". Archived from the original on 23 September 2017. Retrieved 23 April 2018.
  7. ^ "Jimmy Carter timeline". Archived from the original on 29 March 2010. Retrieved 23 April 2018.
  8. ^ (in English) The Canadian Nuclear FAQ What are the details of the accident at Chalk River's NRX reactor in 1952? Archived 2009-01-30 at the Wayback Machine
  9. ^ The Canadian Nuclear FAQ What are the details of the accident at Chalk River's NRU reactor in 1958? Archived 2009-01-30 at the Wayback Machine
  10. ^ Archived 2009-01-30 at the Wayback Machine What are the details of the accident at Chalk River's NRU reactor in 1958?
  11. ^ "The Canadian Nuclear FAQ - Section D: Safety and Liability". Archived from the original on 6 October 2017. Retrieved 23 April 2018.
  12. ^ [1] Archived April 2, 2008, at the Wayback Machine
  13. ^ Archived from the original on April 3, 2008. Retrieved December 14, 2007. Missing or empty |title= (help)
  14. ^ Ljunggren, David (2007-12-12). "Canadian parliament orders isotope reactor restart". Reuters. Archived from the original on 2009-06-03. Retrieved 2013-05-05.
  15. ^ Sunday, May 5, 2013 3:49 PM EDT Facebook Twitter RSS (2007-12-13). "Much more at stake than medical isotopes | Toronto Star". Archived from the original on October 2, 2012. Retrieved 2013-05-05.CS1 maint: Multiple names: authors list (link)
  16. ^ "Chalk River plant to begin making radioisotopes in a week - Canada - CBC News". 2007-12-13. Archived from the original on 2010-09-26. Retrieved 2013-05-05.
  17. ^ Citizen, Ottawa (2008-01-16). "Harper government fires Linda Keen over isotope crisis". Archived from the original on 2012-11-10. Retrieved 2013-05-05.
  18. ^ "Current Issues - CNSC Report to Minister of Natural Resources regarding recent events at National Research Universal (NRU) Reactor". Archived from the original on 2013-12-22. Retrieved 2013-05-05.
  19. ^ "Agency says it was told of nuke leak within hours | CTV News". 2009-01-27. Archived from the original on 2009-06-04. Retrieved 2013-05-05.
  20. ^ "Archived copy". Archived from the original on 2009-06-15. Retrieved 2009-02-06.CS1 maint: Archived copy as title (link)
  21. ^ "News Releases". Archived from the original on 2012-02-29. Retrieved 2013-05-05.
  22. ^ "Canada's NRU reactor in Chalk River is being turned off for good - CBC News". Archived from the original on 9 April 2018. Retrieved 23 April 2018.
  23. ^ "Canadian isotope reactor enters retirement - World Nuclear News".

External links

Atomic Energy of Canada Limited

Atomic Energy of Canada Limited (AECL; French: Énergie atomique du Canada limitée (EACL)) 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 (a wholly owned subsidiary of SNC-Lavalin).

Today AECL develops peaceful and innovative applications from nuclear technology through expertise in physics, metallurgy, chemistry, biology and engineering. AECL's activities range from research and development, design and engineering to specialized technology development, waste management and decommissioning. AECL partners with Canadian universities, other Canadian government and private-sector R&D agencies (including Candu Energy), various national laboratories outside Canada, and international agencies such as the IAEA.

AECL describes its goal as ensuring that "Canadians and the world receive energy, health, environmental and economic benefits from nuclear science and technology - with confidence that nuclear safety and security are assured".

Until October 2011 AECL was also the vendor of CANDU technology, which it had exported worldwide. Throughout the 1960s-2000s AECL marketed and built CANDU facilities in India, South Korea, Argentina, Romania, and the People's Republic of China. It is a member of the World Nuclear Association trade group.

In addition, AECL manufactures nuclear medicine radioisotopes for supply to MDS Nordion in Ottawa, Ontario, and is the world's largest supplier of molybdenum-99 for diagnostic tests, and cobalt-60 for cancer therapy.

AECL is funded through a combination of federal government appropriations and commercial revenue. In 2009, AECL received $651 million in federal support.In October 2011 the federal government of Canada sold the commercial CANDU design and marketing business of AECL to Candu Energy for $15 million (including 15 years worth of royalties, the government could get back as much as $285 million). The sale entered the exclusive negotiation stage in February, a month after the other bidder, Bruce Power pulled out). Poor sales and cost overruns ($1.2 billion in the last five years) were reasons for the divestment though SNC-Lavalin expects to reverse that trend by focusing on new generation reactors. SNC-Lavalin Nuclear Inc, SNC's nuclear subsidiary is already part of Team CANDU, a group of five companies that manufacture and refurbish the CANDU reactors. The government will continue to own the Chalk River Laboratories (produces isotopes for medical imaging). The transaction puts 800 jobs at risk while improving job security for 1,200 employees. Due to safety concerns many countries are considering thorium nuclear reactors which AECL's CANDU reactors easily convert into (from uranium fuelled). Higher energy yields using thorium as the fuel (1 ton of thorium produces the same amount of energy as 200 tons of uranium) also makes it more attractive. OMERS has also shown interest in the company.


CKML is a 50-watt radio station owned by Atomic Energy of Canada Limited through licensee "The Security Systems Coordinator, Chalk River Laboratories" that operates at 530 kHz in Chalk River, Ontario, Canada. The station is designed solely to broadcast emergency information in event of an accident at the laboratory.

The station was approved by the Canadian Radio-television and Telecommunications Commission (CRTC) in 1998. CKML, is not considered as a continuous broadcasting station. The service is tested for one hour each month and, once a year, a two-hour emergency exercise will be carried out. In a real emergency situation, the service could be used for many hours.

The "ML" in the CKML callsign refers to Mark Ling of Chalk River Laboratories.

Canadian Neutron Beam Centre

The NRC Canadian Neutron Beam Centre (CNBC) is Canada's national user facility that enables researchers to use neutron beams as tools for world-class materials research. The CNBC is located at Chalk River Laboratories, where Atomic Energy of Canada Limited (AECL) owns and operates the National Research Universal (NRU) reactor. CNBC has been a global leader in the development of materials and products for businesses. Like most other neutron beam laboratories, the CNBC operates beamlines as a service to external researchers. In a typical year, about 250 individuals participate in research that relies on access to its suite of 6 beamlines at the CNBC.

Chalk River

Chalk River (2016 population: 1029) is a small rural village, part of the Laurentian Hills municipality in Renfrew County, Ontario, Canada. It is located in the Upper Ottawa Valley along Highway 17 (Trans-Canada Highway), 10 km inland (west) from the Ottawa River, approximately 21 km northwest of Petawawa, and 182 km northwest of Ottawa. Chalk River was a separate municipality until January 1, 2000, when the United Townships of Rolph, Buchanan, Wylie and McKay and the Village of Chalk River were merged.Chalk River's area is environmentally pristine with extensive forests, hills and numerous small lakes all of which support a variety of wildlife typical to the southern edge of the Canadian Shield.

St. Anthony's Elementary School is the only educational institution in the community, instructing grades Junior Kindergarten to Grade 8. It provides catholic education to the children in the neighborhood, with a church next door. Students in higher grades are bussed to nearby Deep River.

The town consists mainly of detached houses with some townhouses and an apartment building. Local services include stores (DJ's Variety), a gas station, and a restaurant (Treetop). The Chalk River library, the Lions Hall, and the Legion all play an important part in the community.

Local recreational activities include hiking, fourwheeling, and biking. In the winter, snowmobile and cross country ski trails can be enjoyed. A skating rink and baseball diamond are also present.

Deep River, Ontario

Deep River is a town in Renfrew County, Ontario, Canada. Located along the Ottawa River, it lies about 200 kilometres (120 mi) north-west of Ottawa on the Trans-Canada Highway. Deep River is opposite the Laurentian Mountains and the Province of Quebec. The name Deep River purportedly derives from the fact that the Ottawa River reaches its greatest depth of 402 feet (123 m) just outside the township. However, the Ottawa River reaches a depth of 565 feet (172 m) in Moose Bay which is located on the Holden Lake section west of Deux-Rivières.

The primary industry centres on research at the Chalk River location of Canadian Nuclear Laboratories (CNL), a facility of the Chalk River Laboratories about 10 km east of Deep River on Highway 17. The facility is named for, and primarily accessed via, the nearby town Chalk River, although the site is technically in Deep River.

Property taxes make up the majority of Deep River's budget.

Deep River Science Academy

The Deep River Science Academy (DRSA) was a private non-profit organization located in Deep River, Ontario. It was devoted to education and advancement of science in Canada. Thousands of students (both high school and university) and scientists have participated in a variety of joint science-research projects organized by the DRSA since 1987. The Deep River Science Academy cooperated with Atomic Energy of Canada Limited, Chalk River Laboratories, and other knowledge economy organizations in the Upper Ottawa Valley.

In 2004, the DRSA received the Michael Smith Award for Science Promotion.

On December 16, 2016, it was announced that the Deep River Science Academy was shut down. Exact reasons cannot be confirmed, but lack of funding may be the cause based on one of their website's pages.

John Cockcroft

Sir John Douglas Cockcroft, (27 May 1897 – 18 September 1967) was a British physicist who shared with Ernest Walton the Nobel Prize in Physics in 1951 for splitting the atomic nucleus, and was instrumental in the development of nuclear power.

After service on the Western Front with the Royal Field Artillery during the Great War, Cockcroft studied electrical engineering at Manchester Municipal College of Technology whilst he was an apprentice at Metropolitan Vickers Trafford Park and was also a member of their research staff. He then won a scholarship to St. John's College, Cambridge, where he sat the tripos exam in June 1924, becoming a wrangler. Ernest Rutherford accepted Cockcroft as a research student at the Cavendish Laboratory, and Cockcroft completed his doctorate under Rutherford's supervision in 1928. With Ernest Walton and Mark Oliphant he built what became known as a Cockcroft–Walton accelerator. Cockcroft and Walton used this to perform the first artificial disintegration of an atomic nucleus, a feat popularly known as splitting the atom.

During the Second World War Cockcroft became Assistant Director of Scientific Research in the Ministry of Supply, working on radar. He was also a member of the committee formed to handle issues arising from the Frisch–Peierls memorandum, which calculated that an atomic bomb could be technically feasible, and of the MAUD Committee which succeeded it. In 1940, as part of the Tizard Mission, he shared British technology with his counterparts in the United States. Later in the war, the fruits of the Tizard Mission came back to Britain in the form of the SCR-584 radar set and the proximity fuze, which were used to defeat the V-1 flying bomb. In May 1944, he became director of the Montreal Laboratory, and oversaw the development of the ZEEP and NRX reactors, and the creation of the Chalk River Laboratories.

After the war Cockcroft became the director of the Atomic Energy Research Establishment (AERE) at Harwell, where the low-powered, graphite-moderated GLEEP became the first nuclear reactor to operate in western Europe when it was started on 15 August 1947. This was followed by BEPO in 1948. Harwell was involved in the design of the reactors and the chemical separation plant at Windscale. Under his direction it took part in frontier fusion research, including the ZETA program. His insistence that the chimney stacks of the Windscale reactors be fitted with filters was mocked as Cockcroft's Folly until the core of one of the reactors ignited and released radionuclides during the Windscale fire of 1957.

From 1959 to 1967, he was the first Master of Churchill College, Cambridge. He was also chancellor of the Australian National University in Canberra from 1961 to 1965.

Leo Yaffe

Leo Yaffe, (July 6, 1916 – May 14, 1997) was a Canadian nuclear chemistry scientist and a proponent of the peaceful uses of nuclear power.

Born in Devils Lake, North Dakota, his family moved to Winnipeg in 1920. He studied at the University of Manitoba receiving a B.Sc.(Hons) in 1940, a M.Sc in 1941, and was awarded an honorary D.Sc in 1982. He received a Ph.D in 1943 from McGill University.

In 1943, he was recruited by Atomic Energy of Canada Limited to work at the Manhattan Project's Montreal Laboratory, moving to the Chalk River Laboratories, on the banks of the Ottawa River, in Ontario, at the end of the war. He remained with the AECL until 1952.

In 1952, he moved to Montreal, where the J.S. Foster cyclotron had just been built at McGill University. In 1958 he became the Macdonald Professor of Chemistry.

From 1963 to 1965 he was director of research at the International Atomic Energy Agency in Vienna. Returning to McGill he was appointed head of the Department of Chemistry until 1972. In 1974 he was appointed Vice-Principal (administration) which he held until he retired in 1981. From 1981 to 1982, he was the president of the Chemical Institute of Canada.

He married Betty Workman and has two children: Carla Krasnick, and Mark Yaffe. Yaffe died in Montreal in 1997. The McGill University Archives holds a collection of his personal papers and photographs.

Montreal Laboratory

The Montreal Laboratory in Montreal, Quebec, Canada, was established by the National Research Council of Canada during World War II to undertake nuclear research in collaboration with the United Kingdom, and to absorb some of the scientists and work of the Tube Alloys nuclear project in Britain. It became part of the Manhattan Project, and designed and built some of the world's first nuclear reactors.

After the Fall of France, some French scientists escaped to Britain with their stock of heavy water. They were temporarily installed in the Cavendish Laboratory at the University of Cambridge, where they worked on reactor design. The MAUD Committee was uncertain whether this was relevant to the main task of Tube Alloys, that of building an atomic bomb, although there remained a possibility that a reactor could be used to breed plutonium, which might be used in one. It therefore recommended that they be relocated to the United States, and co-located with the Manhattan Project's reactor effort. Due to American concerns about security (many of the scientists were foreign nationals) and patent claims by the French scientists and Imperial Chemical Industries (ICI), it was decided to relocate them to Canada instead.

The Canadian government agreed to the proposal, and the Montreal Laboratory was established in a house belonging to McGill University; it moved to permanent accommodation at the Université de Montréal in March 1943. The first eight laboratory staff arrived in Montreal at the end of 1942. These were Bertrand Goldschmidt and Pierre Auger from France, George Placzek from Czechoslovakia, S. G. Bauer from Switzerland, Friedrich Paneth and Hans von Halban from Austria, and R. E. Newell and F. R. Jackson from Britain. The Canadian contingent included George Volkoff, Bernice Weldon Sargent and George Laurence, and promising young Canadian scientists such as J. Carson Mark, Phil Wallace and Leo Yaffe.

Although Canada was a major source of uranium ore and heavy water, these were controlled by the Americans. Anglo-American cooperation broke down, denying the Montreal Laboratory scientists access to the materials they needed to build a reactor. In 1943, the Quebec Agreement merged Tube Alloys with the American Manhattan Project. The Americans agreed to help build the reactor. Scientists who were not British subjects left, and John Cockcroft became the new director of the Montreal Laboratory in May 1944. The Chalk River Laboratories opened in 1944, and the Montreal Laboratory was closed in July 1946. Two reactors were built at Chalk River. The small ZEEP went critical on 5 September 1945, and the larger NRX on 21 July 1947. NRX was for a time the most powerful research reactor in the world.


NRX (National Research Experimental) was a heavy-water-moderated, light-water-cooled, nuclear research reactor at the Canadian Chalk River Laboratories, which came into operation in 1947 at a design power rating of 10 MW (thermal), increasing to 42 MW by 1954. At the time of its construction it was Canada's most expensive science facility and the world's most powerful nuclear research reactor.

NRX was remarkable both in terms of its heat output and the number of free neutrons it generated. When a nuclear reactor is operating its nuclear chain reaction generates many free neutrons, and in the late 1940s NRX was the most intense neutron source in the world.

NRX experienced one of the world's first major reactor accidents on 12 December 1952. The reactor began operation on 22 July 1947 under the National Research Council of Canada, and was taken over by Atomic Energy of Canada Limited (AECL) shortly before the 1952 accident. The accident was cleaned up and the reactor restarted within two years. NRX operated for 45 years, being shut down permanently on 30 March 1993. It is currently undergoing decommissioning at the Chalk River Laboratories site.

NRX was the successor to Canada's first reactor, ZEEP. Because the operating life of a research reactor was not expected to be very long, in 1948 planning started for construction of a successor facility, the National Research Universal reactor, which went critical in 1957.

National Research Universal reactor

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 isotopes used to treat or diagnose over 20 million people in 80 countries every year (and, to a lesser extent, other isotopes used for non-medical purposes). 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.

Norman Moody

Norman Moody (December 22, 1915 - October 23, 2004) was a British-Canadian electrical engineer. Born in England, he first worked at Halcyon Radio, where he worked on the design and production of early electronic television sets. During the Second World War he worked at the Telecommunications Research Establishment developing airborne radar systems. He emigrated to Canada after the war and joined the National Research Council Chalk River Laboratories, where he developed nuclear instrumentation. In 1951-1952 he worked on instrumentation for the British atomic bomb tests. At the (Canadian) Defence Research Telecommunications Establishment, he was involved in the development of the DRTE Computer, which also was an introduction to semiconductors for the Canadian military. In 1959 Norman Moody became the head of Electrical Engineering at the University of Saskatchewan, where he developed Canada's first raduate program in biomedical engineering. He transferred in 1962 to become director of the Institute of Biomedical Electronics in Toronto until his retirement in 1975.

Norman Moody was made a Fellow of the Institution of Electrical Engineers in 1962, and elected as a Fellow of the Royal Society of Canada in 1972.

Nuclear Power Demonstration

Nuclear Power Demonstration (or NPD) was the first Canadian nuclear power reactor, and the prototype for the CANDU reactor design. Built by Canadian General Electric (now GE Canada), in partnership with Atomic Energy of Canada Limited (AECL) and Ontario Hydro (now Ontario Power Generation), it consisted of a single 22 MWe pressurized heavy water reactor (PHWR) unit located in Rolphton, Ontario, not far from AECL's Chalk River Laboratories. NPD was owned by AECL and operated by Ontario Hydro.

The NPD was the prototype and proving ground for research and development that led to commercial application of the CANDU system for generating electric power from a nuclear plant using natural uranium fuel, heavy water moderator and coolant in a pressure tube configuration with on-power refuelling.

P-9 Project

The P-9 Project was the codename given during World War II to the Manhattan Project's heavy water production program. The Cominco plant at Trail, British Columbia, was upgraded to produce heavy water. DuPont built three plants in the United States: at the Morgantown Ordnance Works, near Morgantown, West Virginia; at the Wabash River Ordnance Works, near Dana and Newport, Indiana; and at the Alabama Ordnance Works, near Childersburg and Sylacauga, Alabama. The American plants operated from 1943 until 1945. The Canadian plant at Trail continued in operation until 1956. Three nuclear reactors were built using the heavy water produced by the P-9 Project: Chicago Pile 3 at Argonne, and ZEEP and NRX at the Chalk River Laboratories in Canada.

Research reactor

Research reactors are 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.

Tandem Accelerator Superconducting Cyclotron

Tandem Accelerator Superconducting Cyclotron (TASCC) was an accelerator facility constructed at Chalk River Laboratories on October 3, 1986. TASCC was the world's first Tandem Accelerator and able to accelerate most elements to 10 MeV per nucleon. The TASCC facility was decommissioned beginning in 1996.

Varley F. Sears

Varley Fullerton Sears is a Canadian physicist, notable for his contributions to the methodological foundations of neutron scattering.

In 1960, Sears obtained a Ph.D. from the University of Toronto with a thesis on The rotational absorption spectrum of solid and liquid parahydrogen. From 1963 to 1965, the National Research Council of Canada sent him as an Overseas Postdoctoral Fellow to the Clarendon Laboratory in Oxford where he was hosted by Roger James Elliott and worked on Raman scattering by semiconductors. Back in Canada, he became a staff scientist in the Theoretical Physics Branch of Chalk River Laboratories. In 1966/67, he published seminal papers on neutron spectra of molecular rotors. By the 1980s, he had become a leading expert in neutron optics, publishing a review and a textbook on the subject. Based on these foundations, he compiled authoritative tables of neutron scattering lengths. In 1997, he published a generic solution of the Darwin-Hamilton equations that provide an approximative description of multiple Bragg reflection by a mosaic crystal.


ZED-2 (Zero Energy Deuterium) is a zero-power nuclear research reactor built at the Chalk River Laboratories in Ontario, Canada. It is the successor to the ZEEP reactor. Designed by AECL for CANDU reactor support, the unit saw first criticality on 7 September 1960. The reactor is still operating at Chalk River where it is used for reactor physics and nuclear fuel research.


The ZEEP (Zero Energy Experimental Pile) reactor was a nuclear reactor built at the Chalk River Laboratories near Chalk River, Ontario, Canada (which superseded the Montreal Laboratory for nuclear research in Canada). ZEEP first went critical at 15:45 on September 5, 1945. ZEEP's was the first operational nuclear reactor outside the United States.The reactor was designed by Canadian, British and French scientists as a part of an effort to produce plutonium for nuclear weapons during World War II. It was developed while the Montreal Laboratory and Chalk River Laboratories research facility were under the supervision of the National Research Council of Canada (NRC). ZEEP was instrumental in the development of the NRX and NRU reactors, which led to the development of the successful CANDU reactor. ZEEP was used to test reactivity effects and other physics parameters needed for reactor development at Chalk River Laboratories, including fuel lattices for the NRU reactor situated next door.

ZEEP was one of the world's first heavy water reactors, and it was also designed to use natural (unenriched) uranium; a feature carried through to the CANDU design. Uranium enrichment is a complex and expensive process; thus, the ability to use unenriched uranium gave ZEEP and its descendants a number of distinct advantages.

ZEEP continued to be used for basic research until 1970. It was decommissioned in 1973 and dismantled in 1997. In 1966 ZEEP was designated a historic site by Ontario, and commemorated with an historic plaque. Both this plaque and ZEEP itself are now on display at the Canada Science and Technology Museum in Ottawa, Canada.

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