Chalk River Laboratories (also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories) is a Canadian nuclear research facility in Deep River near Chalk River, about 180 km (110 mi) north-west of Ottawa.
CRL is a significant research and development site to support and advance nuclear technology, particularly CANDU reactor technology. CRL has expertise in physics, metallurgy, chemistry, biology, and engineering and hosts unique research facilities. For example, Bertram Brockhouse, a McMaster University professor, 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. Until the shutdown of its nuclear reactor in 2018, CRL produced a large share of the world's supply of medical radioisotopes. The Canadian Nuclear Laboratories subsidiary of Atomic Energy of Canada Limited was owned and operated under contract by the Canadian National Energy Alliance, a private-sector consortium led by SNC-Lavalin.
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 the Chalk River.
In 1952, the government created Atomic Energy of Canada Limited (AECL) to promote nuclear energy's peaceful use. AECL also took over the operation of Chalk River from the NRC. AECL, since the 1950s, has operated various atomic research reactors to produce nuclear material for medical and scientific applications. The Laboratories make about one-third of the world's medical isotopes and 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. (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 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 the Chalk River.
1952 NRX incident
Chalk River was also the site of two nuclear accidents in the 1950s. The first incident occurred in 1952 when there were 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. Hydrogen explosions seriously damaged the reactor and the reactor building. The blast blew the seal of the reactor vessel up four feet. As such, 4,500 tons of radioactive water were found in the building's cellar, dumped in ditches around 1,600 meters from the Ottawa River's border. Some 10,000 curies or 370 TBq of radioactive material was released during this accident. Future U.S. president Jimmy Carter, then a U.S. Navy officer in Schenectady, NY, led a team of 26 men, including 13 U.S. Navy volunteers, in the hazardous cleanup. Arthur V. McKeon and Fred Hieber were among the U.S. Navy volunteers. Two years later, the reactor was in use again.
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, which pulled one of the rods with a robotic crane with metallic uranium out of the reactor vessel. When the crane's arm moved away from the vessel, the uranium caught fire, and the rod broke. The most significant part of the rod fell 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. Scientists and maintenance men extinguished the fire. They did so wearing protective clothing running along the hole in the containment vessel with buckets of wet sand, throwing the sand down when they passed the smoking entrance.
Both accidents required a significant 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. 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 an army disability pension due to health damages.
Chalk River Laboratories remain an AECL facility to this day. They are used as both research (in partnership with the NRC) and production facility (on behalf of AECL) to support other Canadian electrical utilities.
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). AECL decided to connect seismically qualified emergency power supplies (EPS) to two of the reactor's cooling pumps. The EPS was 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 made most of the world's supply of medical radioisotopes, including two-thirds of the world's technetium-99m.
On December 11, 2007, the House of Commons of Canada, acting on independent expert advice, passed emergency legislation authorising 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 criticised the CNSC for this shutdown which "jeopardised 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 lose her job for ignoring Parliament's decision to restart the reactor, reflecting its policy that they should take citizens safety requiring essential nuclear medicine to assess the overall safety concerns of the reactor's operation. The NRU reactor was restarted on December 16, 2007.
2008 radioactive leakage
On December 5, 2008, heavy water containing tritium leaked from the NRU. The leaked water was contained within the facility, and the Canadian Nuclear Safety Commission (CNSC) was notified immediately, as required.
On December 9, 2008, upon the leakage being determined to meet the requirements for a formal report issued to the CNSC, AECL mentioned that 47 litres of heavy water were released from the reactor. About 10% of the leak evaporated, and the rest was contained, but AECL affirmed that the spill was not severe and did not present a threat to public health. The amount evaporated into the atmosphere is considered minor, accounting for less than a thousandth of the regulatory limit. The public was informed of the shutdown at the reactor, but not the leakage details 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 leaked 7,001 litres of light water per day from a crack in a weld of the reactor's reflector system. This water was being systematically collected, purified in an on-site Waste Treatment Centre, and eventually released to the Ottawa River following 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, AECL made 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 when only one of the other four worldwide regular medical isotope sourcing reactors produced, resulting in a global shortage.
NRU shut down in March 2018
The NRU reactor licence was due to expire in 2016 but was extended to March 31, 2018. The reactor was shut down for the last time at 7 p.m. on March 31, 2018, and has entered a "state of storage" before decommissioning operations that will continue for many years within the future operating scope or decommissioning licences issued by the CNSC.