National Research Universal Reactor
Encyclopedia
The National Research Universal (NRU) reactor, located in Chalk River, Ontario
, is one of Canada’s national science facilities. It is a multipurpose science facility that serves three main roles.
With the construction of the earlier NRX
reactor, it was possible for the first time to commercially manufacture isotopes that were not commonly found in nature. In the core of an operating reactor there are billions of free neutrons. By inserting a piece of target material into the core, atoms in the target can capture some of those neutrons and become heavier isotopes. Manufacturing medical isotopes was a Canadian medical innovation in the early 1950s.
The NRU reactor continued the legacy of NRX and today produces more medical isotopes than any facility in the world.
The core of the NRU reactor is about 3 m wide and 3 m high, which is unusually large for a research reactor. That large volume enables the bulk production of isotopes. Other research reactors in the world produce isotopes for medical and industrial uses, for example the European High Flux Reactor
at Petten in the Netherlands, and the OPAL
reactor in Australia which began operation in April 2007.
: the NRC
Canadian Neutron Beam Centre
. Neutron scattering is a technique where a beam of neutrons shines through a sample of material, and depending on how the neutrons scatter from the atoms inside, scientists can determine many details about the crystal structure and movements of the atoms within the sample.
An early pioneer of the technique was Bertram Brockhouse who built some of the early neutron spectrometers in the NRX and NRU reactors and was awarded the 1994 Nobel Prize in physics for the development of neutron spectroscopy.
The NRC Canadian Neutron Beam Centre continues that field of science today, operating as an open-access user facility allowing scientists from across Canada and around the world to use neutrons in their research programs.
It is common for a developed country to support a national facility for neutron scattering and one for X-ray scattering
. The two types of facility provide complementary information about materials.
An unusual feature of the NRU reactor as Canada's national neutron source is its multipurpose design: able to manufacture isotopes, and support nuclear R&D at the same time as it supplies neutrons to the suite of neutron scattering instruments.
The NRU reactor is sometimes (incorrectly) characterized as simply a nuclear research facility. Neutron scattering however is not nuclear research
, it is materials research. Neutrons are an ideal probe of materials including metals, alloys, biomaterials, ceramics, magnetic materials, minerals, polymers, composites, glasses, nano-materials and many others. The neutron scattering instruments at the NRC
Canadian Neutron Beam Centre
are used by universities and industries from across Canada every year because knowledge of materials is important for innovation in many sectors.
The NRU reactor has test facilities built into its core that can replicate conditions inside a large electricity-producing reactor. NRU itself does not generate steam (or electricity); its cooling water heats up to approximately 55 degrees Celsius. Inside the test facilities though, high temperatures and pressures can be produced. It is essential to test out different materials before they are used in the construction of a nuclear generating station.
The fundamental knowledge gained from NRU enabled the development of the CANDU reactor
, and is the foundation for the Canadian nuclear industry
.
at Chalk River Laboratories
. The NRX reactor was the world's most intense source of neutron
s when it started operation in 1947 and had attracted a large scientific community who were using those neutrons in research that was then possible for the first time. It was not known how long a research reactor could be expected to operate so the management of Chalk River Laboratories began planning the NRU reactor to ensure continuity of the research programs.
NRU started self-sustained operation (or went "critical") on November 3, 1957, a decade after NRX, and was ten times more powerful. It was initially designed as a 200 MW reactor, fueled with natural uranium
. NRU was converted to 60 MW with highly-enriched uranium
(HEU) fuel in 1964 and converted a third time in 1991 to 135 MW running on low-enriched uranium (LEU) fuel.
On 24 May 1958 the NRU suffered a major accident. A damaged uranium fuel rod caught fire and was torn in two as it was being removed from the core. The fire was extinguished, but a sizeable quantity of radioactive combustion products had contaminated the interior of the reactor building and, to a lesser degree, an area of the surrounding laboratory site. The clean-up and repair took three months. NRU was operating again in August 1958. Care was taken to ensure no one was exposed to dangerous levels of radiation and staff involved in clean-up were monitored over the following decades. No health effects were observed.
NRU's calandria, the vessel which contains its nuclear reactions, is made of aluminum, and was replaced in 1971 because of corrosion. But it has not been replaced since, although this second replacement is likely needed. A complete shutdown of perhaps one year would be needed for the replacement. One strong advantage of NRU's design is that it can be taken apart to allow for replacements such as this. Since NRX was decommissioned in 1992, after 45 years of service, there has been no backup for NRU.
In October 1986, the NRU reactor was recognized as a nuclear historic landmark by the American Nuclear Society
.
In 1994, Bertram Brockhouse was awarded the Nobel Prize in Physics
, for his pioneering work carried out in the NRX and NRU reactors in the 1950s. He gave birth to a scientific technique which is now used around the world.
In 1996, AECL
informed the Canadian Nuclear Safety Commission
(then known as the Atomic Energy Control Board) that operation of the NRU reactor would not continue beyond December 31, 2005. It was expected that a replacement facility would be built inside that time. However, no replacement was built and in 2003, AECL advised the CNSC that they intended to continue operation of the NRU reactor beyond December 2005. The operating licence was initially extended to July 31, 2006, and a 63-month licence renewal was obtained in July 2006, allowing full operating of NRU until October 31, 2011.
In May 2007, the NRU reactor set a new record for the production of medical isotopes.
In June 2007, a new neutron scattering
instrument was opened in NRU. The D3 Neutron Reflectometer is designed for examining surfaces, thin films and interfaces. The technique of Neutron Reflectometry
is relatively new, and capable of providing unique information on materials in the nanometre length scale.
(CNSC), whose staff had discovered that the status of the NRU facility was not in compliance with CNSC license conditions. This resulted in a worldwide shortage of radioisotopes for medical treatments because Chalk River makes the majority of the world's supply of radioisotopes, (including two-thirds of the world's technetium-99
) and because AECL had not pre-arranged for an alternate supply. On December 11, 2007, the Canadian House of Commons
, acting on what the government described as "independent expert" advice, passed emergency legislation authorizing the restarting of the NRU reactor with one of the two seismic connections complete (one pump being sufficient to cool the core), and authorizing the reactor's operation for 120 days without CNSC approval. The legislation, C-38, was passed by the Senate and received Royal Assent on December 12. Prime Minister Stephen Harper
accused the "Liberal-appointed" CNSC for this shutdown which "jeopardized the health and safety of tens of thousands of Canadians". Others viewed the actions and priorities of the Prime Minister and government in terms of protecting the eventual sale of AECL to private investors. The government later announced plans to sell part of AECL in May 2009.
The NRU reactor was restarted on December 16, 2007.
On January 29, 2008, the former President of the CNSC, Linda Keen, testified before a Parliamentary Committee that the risk of fuel failure in the NRU reactor was "1 in 1000 years", and claimed this to be a thousand times greater risk than the "international standard". These claims were refuted by AECL.
On February 2, 2008 the second seismic connection was complete. This timing was well within the above 120-day window afforded by Bill C-38.
The reactor remained shut down 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.
Chalk River, Ontario
Chalk River is a Canadian rural community part of the Laurentian Hills municipality in Renfrew County, Ontario. It is located in the Upper Ottawa Valley along Highway 17 , 10 km inland from the Ottawa River, approximately 21 km northwest of Petawawa, and 182 km northwest of Ottawa...
, is one of Canada’s national science facilities. It is a multipurpose science facility that serves three main roles.
- It generates isotopesNuclear medicineIn nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs...
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 is the neutron source for the NRCNational Research Council of CanadaThe National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
Canadian Neutron Beam CentreCanadian Neutron Beam CentreThe NRC Canadian Neutron Beam Centre is Canada's national centre for materials research using neutrons, and is one of the Chalk River Laboratories. Neutrons are a unique and versatile tool for research in materials of all kinds. This field of science is known as neutron scattering....
: a materials research centre that grew from the Nobel Prize-winning work of Bertram BrockhouseBertram BrockhouseBertram Neville Brockhouse, was a Canadian physicist. He was awarded the Nobel Prize in Physics "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter", in particular "for the development of neutron spectroscopy".-Life:Brockhouse was...
. - It is the test bed for Atomic Energy of Canada LimitedAtomic Energy of Canada LimitedAtomic Energy of Canada Limited or AECL is a Canadian federal Crown corporation and Canada's largest nuclear science and technology laboratory...
to develop fuels and materials for the CANDU reactorCANDU reactorThe CANDU reactor is a Canadian-invented, pressurized heavy water reactor. The acronym refers to its deuterium-oxide moderator and its use of uranium fuel...
.
Isotopes
| Atom Atom The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons... s are the building blocks of nature. The periodic table Periodic table The periodic table of the chemical elements is a tabular display of the 118 known chemical elements organized by selected properties of their atomic structures. Elements are presented by increasing atomic number, the number of protons in an atom's atomic nucleus... of the elements lists as many as 118 different types of atom Atom The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons... , called elements, such as hydrogen Hydrogen Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly... , nitrogen Nitrogen Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere... or carbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds... . Atoms of any element can occur in more than one weight, depending on the number of neutron Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... s they contain. Two atoms of carbon Carbon Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds... for instance may weigh 12 and 13 a.m.u. Atomic mass unit The unified atomic mass unit or dalton is a unit that is used for indicating mass on an atomic or molecular scale. It is defined as one twelfth of the rest mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state, and has a value of... . They are both carbon atoms, but one has an extra neutron. They are referred to as isotope Isotope Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation... s of carbon. Not all isotope Isotope Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation... s are stable. An unstable isotope will decay Radioactive decay Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom... to a more stable state, releasing energy and possibly one or more particles. These particles and/or the energy emitted by said radioisotopes is used in a great variety of medical, industrial and scientific applications. |
With the construction of the earlier NRX
NRX
NRX 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 , increasing to 42 MW by 1954...
reactor, it was possible for the first time to commercially manufacture isotopes that were not commonly found in nature. In the core of an operating reactor there are billions of free neutrons. By inserting a piece of target material into the core, atoms in the target can capture some of those neutrons and become heavier isotopes. Manufacturing medical isotopes was a Canadian medical innovation in the early 1950s.
The NRU reactor continued the legacy of NRX and today produces more medical isotopes than any facility in the world.
- Cobalt-60Cobalt-60Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...
from NRU is used in Radiation therapyRadiation therapyRadiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
machines that treat cancer in 15 million patients in 80 counties each year. The NRU produces about 75% of the global supply. Cobalt-60 emits a lot of energy as it decays, enough to kill a cancer cell. - Technetium-99mTechnetium-99mTechnetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc. The "m" indicates that this is a metastable nuclear isomer, i.e., that its half-life of 6 hours is considerably longer than most nuclear isomers that undergo gamma decay...
from NRU is used in the diagnosis of 5 million patients each year, representing about 80 per cent of all nuclear medicine procedures. The NRU produces over half of the world's total supply. Technetium-99m emits less energy as it decays than most gamma emitters, roughly as much as the X-rays from an X-ray tube. This can act as an in situ source for a special camera that creates an image of the patient called a SPECT scan. NRU actually produces the more stable parent isotope, molybdenum-99, which is shipped to medical labs. There it decays into technetium-99mTechnetium-99mTechnetium-99m is a metastable nuclear isomer of technetium-99, symbolized as 99mTc. The "m" indicates that this is a metastable nuclear isomer, i.e., that its half-life of 6 hours is considerably longer than most nuclear isomers that undergo gamma decay...
, which is separated and used for testing. - NRU produces xenon-133, iodine-131 and iodine-125, which are used in a variety of diagnostic and therapeutic applications.
- Carbon-14Carbon-14Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues , to date archaeological, geological, and hydrogeological...
produced in NRU is sold to chemistry, bioscience and environmental labs to use as a tracerCarbon labelCarbon label is a form of isotopic labeling where a carbon-12 atom has been replaced with either a carbon-13 atom or a carbon-14 atom in a chemical compound so as to 'tag' that position of the compound to assist in determining the way a chemical reaction proceeds i.e. the reaction mechanism....
. - Iridium-192 from NRU is used in several industries to inspect welds or other metal components to ensure they are safe for use.
The core of the NRU reactor is about 3 m wide and 3 m high, which is unusually large for a research reactor. That large volume enables the bulk production of isotopes. Other research reactors in the world produce isotopes for medical and industrial uses, for example the European High Flux Reactor
Petten nuclear reactor
The Petten nuclear reactors are nuclear research reactors in Petten, Netherlands. There are two reactors on the premises of the Petten research centre: a high flux reactor and a low flux reactor....
at Petten in the Netherlands, and the OPAL
OPAL
OPAL is a 20 megawatt pool-type nuclear research reactor that was officially opened on 20 April 2007 at the Australian Nuclear Science and Technology Organisation Research Establishment at Lucas Heights, located in South Sydney, Australia.The main reactor uses are:* Irradiation of target...
reactor in Australia which began operation in April 2007.
Neutron beam research
The NRU reactor is home to Canada's national facility for neutron scatteringNeutron scattering
Neutron scattering,the scattering of free neutrons by matter,is a physical processand an experimental technique using this processfor the investigation of materials.Neutron scattering as a physical process is of primordial importance...
: the NRC
National Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
Canadian Neutron Beam Centre
Canadian Neutron Beam Centre
The NRC Canadian Neutron Beam Centre is Canada's national centre for materials research using neutrons, and is one of the Chalk River Laboratories. Neutrons are a unique and versatile tool for research in materials of all kinds. This field of science is known as neutron scattering....
. Neutron scattering is a technique where a beam of neutrons shines through a sample of material, and depending on how the neutrons scatter from the atoms inside, scientists can determine many details about the crystal structure and movements of the atoms within the sample.
An early pioneer of the technique was Bertram Brockhouse who built some of the early neutron spectrometers in the NRX and NRU reactors and was awarded the 1994 Nobel Prize in physics for the development of neutron spectroscopy.
The NRC Canadian Neutron Beam Centre continues that field of science today, operating as an open-access user facility allowing scientists from across Canada and around the world to use neutrons in their research programs.
It is common for a developed country to support a national facility for neutron scattering and one for X-ray scattering
X-ray scattering techniques
X-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystallographic structure, chemical composition, and physical properties of materials and thin films...
. The two types of facility provide complementary information about materials.
An unusual feature of the NRU reactor as Canada's national neutron source is its multipurpose design: able to manufacture isotopes, and support nuclear R&D at the same time as it supplies neutrons to the suite of neutron scattering instruments.
The NRU reactor is sometimes (incorrectly) characterized as simply a nuclear research facility. Neutron scattering however is not nuclear research
Nuclear physics
Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those...
, it is materials research. Neutrons are an ideal probe of materials including metals, alloys, biomaterials, ceramics, magnetic materials, minerals, polymers, composites, glasses, nano-materials and many others. The neutron scattering instruments at the NRC
National Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
Canadian Neutron Beam Centre
Canadian Neutron Beam Centre
The NRC Canadian Neutron Beam Centre is Canada's national centre for materials research using neutrons, and is one of the Chalk River Laboratories. Neutrons are a unique and versatile tool for research in materials of all kinds. This field of science is known as neutron scattering....
are used by universities and industries from across Canada every year because knowledge of materials is important for innovation in many sectors.
Nuclear power research and development
| Inside the core of a large electricity-producing reactor like a CANDU or a PWR Pressurized water reactor Pressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors... , there are a great many free neutrons and high levels of gamma radiation from the nuclear fission Nuclear fission In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy... process. It is important for engineers and scientists to understand how that environment will affect the materials that the reactor is made from. That knowledge is needed to design a reactor with a long service-life. |
The NRU reactor has test facilities built into its core that can replicate conditions inside a large electricity-producing reactor. NRU itself does not generate steam (or electricity); its cooling water heats up to approximately 55 degrees Celsius. Inside the test facilities though, high temperatures and pressures can be produced. It is essential to test out different materials before they are used in the construction of a nuclear generating station.
The fundamental knowledge gained from NRU enabled the development of the CANDU reactor
CANDU reactor
The CANDU reactor is a Canadian-invented, pressurized heavy water reactor. The acronym refers to its deuterium-oxide moderator and its use of uranium fuel...
, and is the foundation for the Canadian nuclear industry
Nuclear power in Canada
Nuclear power in Canada produces about 15% of Canada's electricity as of 2009.-History:The nuclear industry in Canada dates back to 1942 when a joint British-Canadian laboratory, the Montreal Laboratory, was set up in Montreal, Quebec, under the administration of the National Research Council of...
.
History
The NRU reactor design was started in 1949, and is fundamentally a Canadian design, significantly advanced from NRX. It was built as the successor to the NRX reactor at the Atomic Energy Project of the National Research Council of CanadaNational Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
at Chalk River Laboratories
Chalk River Laboratories
The Chalk River Laboratories is a Canadian nuclear research facility located near Chalk River, about north-west of Ottawa in the province of Ontario.CRL is a site of major research and development to support and advance nuclear technology, in particular CANDU reactor...
. The NRX reactor was the world's most intense source of neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s when it started operation in 1947 and had attracted a large scientific community who were using those neutrons in research that was then possible for the first time. It was not known how long a research reactor could be expected to operate so the management of Chalk River Laboratories began planning the NRU reactor to ensure continuity of the research programs.
NRU started self-sustained operation (or went "critical") on November 3, 1957, a decade after NRX, and was ten times more powerful. It was initially designed as a 200 MW reactor, fueled with natural uranium
Natural uranium
Natural uranium refers to refined uranium with the same isotopic ratio as found in nature. It contains 0.7 % uranium-235, 99.3 % uranium-238, and a trace of uranium-234 by weight. In terms of the amount of radioactivity, approximately 2.2 % comes from uranium-235, 48.6 % uranium-238, and 49.2 %...
. NRU was converted to 60 MW with highly-enriched uranium
Enriched uranium
Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...
(HEU) fuel in 1964 and converted a third time in 1991 to 135 MW running on low-enriched uranium (LEU) fuel.
On 24 May 1958 the NRU suffered a major accident. A damaged uranium fuel rod caught fire and was torn in two as it was being removed from the core. The fire was extinguished, but a sizeable quantity of radioactive combustion products had contaminated the interior of the reactor building and, to a lesser degree, an area of the surrounding laboratory site. The clean-up and repair took three months. NRU was operating again in August 1958. Care was taken to ensure no one was exposed to dangerous levels of radiation and staff involved in clean-up were monitored over the following decades. No health effects were observed.
NRU's calandria, the vessel which contains its nuclear reactions, is made of aluminum, and was replaced in 1971 because of corrosion. But it has not been replaced since, although this second replacement is likely needed. A complete shutdown of perhaps one year would be needed for the replacement. One strong advantage of NRU's design is that it can be taken apart to allow for replacements such as this. Since NRX was decommissioned in 1992, after 45 years of service, there has been no backup for NRU.
In October 1986, the NRU reactor was recognized as a nuclear historic landmark by the American Nuclear Society
American Nuclear Society
The American Nuclear Society is an international, not-for-profit 501 scientific and educational organization with a membership of approximately 11,000 scientists, engineers, educators, students, and other associate members. Approximately 900 members live outside the United States in 40 countries....
.
In 1994, Bertram Brockhouse was awarded the Nobel Prize in Physics
Nobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
, for his pioneering work carried out in the NRX and NRU reactors in the 1950s. He gave birth to a scientific technique which is now used around the world.
In 1996, AECL
AECL
AECL is an acronym that can stand for:*Advanced Electronics Company Limited*Atomic Energy of Canada Limited*Australian Egg Corporation Limited...
informed the Canadian Nuclear Safety Commission
Canadian Nuclear Safety Commission
The Canadian Nuclear Safety Commission , previously known as the Atomic Energy Control Board , is the governmental nuclear power and materials watchdog in Canada...
(then known as the Atomic Energy Control Board) that operation of the NRU reactor would not continue beyond December 31, 2005. It was expected that a replacement facility would be built inside that time. However, no replacement was built and in 2003, AECL advised the CNSC that they intended to continue operation of the NRU reactor beyond December 2005. The operating licence was initially extended to July 31, 2006, and a 63-month licence renewal was obtained in July 2006, allowing full operating of NRU until October 31, 2011.
In May 2007, the NRU reactor set a new record for the production of medical isotopes.
In June 2007, a new neutron scattering
Neutron scattering
Neutron scattering,the scattering of free neutrons by matter,is a physical processand an experimental technique using this processfor the investigation of materials.Neutron scattering as a physical process is of primordial importance...
instrument was opened in NRU. The D3 Neutron Reflectometer is designed for examining surfaces, thin films and interfaces. The technique of Neutron Reflectometry
Neutron Reflectometry
Neutron reflectometry is a neutron diffraction technique for measuring the structure of thin films, similar to the often complementary techniques of X-ray reflectivity and ellipsometry...
is relatively new, and capable of providing unique information on materials in the nanometre length scale.
2007 shutdown
On November 18, 2007, the National Research Universal reactor, which makes medical radioisotopes, was shut down for routine maintenance. This shutdown was voluntarily extended when AECL decided to install seismically-qualified emergency power systems (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 license issued by the Canadian Nuclear Safety CommissionCanadian Nuclear Safety Commission
The Canadian Nuclear Safety Commission , previously known as the Atomic Energy Control Board , is the governmental nuclear power and materials watchdog in Canada...
(CNSC), whose staff had discovered that the status of the NRU facility was not in compliance with CNSC license conditions. This resulted in a worldwide shortage of radioisotopes for medical treatments because Chalk River makes the majority of the world's supply of radioisotopes, (including two-thirds of the world's technetium-99
Technetium-99
Technetium-99 is an isotope of technetium which decays with a half-life of 211,000 years to stable ruthenium-99, emitting soft beta rays, but no gamma rays....
) and because AECL had not pre-arranged for an alternate supply. On December 11, 2007, the Canadian House of Commons
Canadian House of Commons
The House of Commons of Canada is a component of the Parliament of Canada, along with the Sovereign and the Senate. The House of Commons is a democratically elected body, consisting of 308 members known as Members of Parliament...
, acting on what the government described as "independent expert" advice, passed emergency legislation authorizing the restarting of the NRU reactor with one of the two seismic connections complete (one pump being sufficient to cool the core), and authorizing the reactor's operation for 120 days without CNSC approval. The legislation, C-38, was passed by the Senate and received Royal Assent on December 12. Prime Minister Stephen Harper
Stephen Harper
Stephen Joseph Harper is the 22nd and current Prime Minister of Canada and leader of the Conservative Party. Harper became prime minister when his party formed a minority government after the 2006 federal election...
accused the "Liberal-appointed" CNSC for this shutdown which "jeopardized the health and safety of tens of thousands of Canadians". Others viewed the actions and priorities of the Prime Minister and government in terms of protecting the eventual sale of AECL to private investors. The government later announced plans to sell part of AECL in May 2009.
The NRU reactor was restarted on December 16, 2007.
On January 29, 2008, the former President of the CNSC, Linda Keen, testified before a Parliamentary Committee that the risk of fuel failure in the NRU reactor was "1 in 1000 years", and claimed this to be a thousand times greater risk than the "international standard". These claims were refuted by AECL.
On February 2, 2008 the second seismic connection was complete. This timing was well within the above 120-day window afforded by Bill C-38.
2009 Shutdown
In mid-May 2009 a heavy water leak at the base of the reactor vessel was detected prompting a temporary shutdown of the reactor. The leak was estimated to be 5KG (<5 litres) per hour and determined to be due to corrosion. This was the second heavy water leak since late 2008. The reactor was defuelled and drained of all of its heavy water moderator. No administrative levels of radioactivity were exceeded, during the leak or defuelling, and all leaked water was contained and treated on site.The reactor remained shut down 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.
See also
- MAPLEMapleAcer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
- Nuclear reactorNuclear reactorA nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...
- Nuclear fissionNuclear fissionIn nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
- Nuclear medicineNuclear medicineIn nuclear medicine procedures, elemental radionuclides are combined with other elements to form chemical compounds, or else combined with existing pharmaceutical compounds, to form radiopharmaceuticals. These radiopharmaceuticals, once administered to the patient, can localize to specific organs...
- Radiation therapyRadiation therapyRadiation therapy , radiation oncology, or radiotherapy , sometimes abbreviated to XRT or DXT, is the medical use of ionizing radiation, generally as part of cancer treatment to control malignant cells.Radiation therapy is commonly applied to the cancerous tumor because of its ability to control...
- Neutron scatteringNeutron scatteringNeutron scattering,the scattering of free neutrons by matter,is a physical processand an experimental technique using this processfor the investigation of materials.Neutron scattering as a physical process is of primordial importance...
- Bertram BrockhouseBertram BrockhouseBertram Neville Brockhouse, was a Canadian physicist. He was awarded the Nobel Prize in Physics "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter", in particular "for the development of neutron spectroscopy".-Life:Brockhouse was...
- Nuclear power plantNuclear power plantA nuclear power plant is a thermal power station in which the heat source is one or more nuclear reactors. As in a conventional thermal power station the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity.Nuclear power plants are usually...
- Nuclear powerNuclear powerNuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
- Nuclear accident
- Nuclear waste
External links
- The NRU Reactor
- NRC Canadian Neutron Beam Centre
- Nuclear Accidents (Georgia State University)
- "The Canadian Nuclear FAQ" by Dr. Jeremy WhitlockWhitlockThe Whitlock company, based in London, England, started as a carriage builder in 1778, moved into the car industry in 1903 and finally closed in 1991....
(in particular see the section "NRU Safety" regarding the Nov-Dec 2007 shutdown of isotope production)