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Operations & Facilities

McMaster Nuclear Reactor

A 5 MW multi-purpose reactor that provides neutrons for research and medical isotope production. It is Canada’s most powerful research reactor and the nation’s only major neutron source.



The McMaster Nuclear Reactor (MNR) first became operational in 1959 and was the first university-based research reactor in the British Commonwealth. Originally designed to operate at a maximum power of 1 MW, MNR was upgraded during the 1970s to its current rating of 5 MW with a maximum thermal neutron flux of 1 x 1014 neutrons/cm2s. MNR is classified as a medium flux reactor and it is by far the most powerful research reactor at a Canadian university – the handful of so-called “Slowpoke” reactors at other institutions typically operate at a power of 0.02 MW.

The McMaster Nuclear Reactor is an open-pool type Materials Test Reactor (MTR) with a core of low enriched uranium (LEU) fuel that is moderated and cooled by light water. Primary and secondary cooling systems act to remove the heat that is generated in the core of the reactor, with external cooling towers acting as the ultimate thermal sink. The reactor is housed within a concrete containment building and generally operates weekdays from 8 a.m. until 12 midnight at a thermal power of 3 MW.

The nuclear reactor was designed with its end use as a multi-purpose research facility in mind. Its open-pool design provides ready access to the reactor core and allows for easy insertion and removal of samples for neutron irradiation, imparting a degree of flexibility that many other classes of reactors lack. As well, several beam-tubes were built into the reactor structure: today, the neutron beams extracted by these tubes are used for applications including neutron radiography and neutron diffraction experiments. MNR also has an industrial hot cell inside the reactor containment building for handling highly radioactive samples.

Staff at the McMaster Nuclear Reactor conduct hundreds of thousands of neutron irradiations every year, many in support of industry (mining exploration, environmental samples). MNR is a world leader in the production of iodine-125, a radioactive isotope that is used in the treatment of prostate cancer, with hundreds of doses produced each week. Neutrons from MNR are also used by Nray Services Inc. to conduct quality assurance testing on turbine blades for jet engines using the neutron radiography facility at one of the beam-ports. Research activities at MNR continue to expand, with a new neutron diffractometer installed in 2009 and a state of the art positron beam facility currently being designed.

McMaster Nuclear Reactor is also involved in public outreach activities such as Doors Open Hamilton, providing opportunities for McMaster students and members of the public to participate in guided tours of the reactor facility. More than 1,500 visitors each year visit MNR to lean about nuclear sciences and observe “the blue glow” of the reactor core first-hand.

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Related Products & Services


Co-60 Irradiations

A 10kCi Co-60 source is housed in the industrial hotcell within containment at the McMaster Nuclear Reactor. Various irradiation’s are routinely done ranging from qualifying nuclear equipment to sterilization and nuclear dating.


Contract Research Services

The flexibility and breadth of our nuclear facilities as well as a strong research environment and staffing faciliates numerous research applications.


Core Irradiations

As Nuclear Operations & Facilities houses a reactor, we are able to conduct in-core irradiations of various lengths of time in order to satisfy research and industrial needs of academic and client services.


Delayed Neutron Counting

DNC is a service provided by the Centre for Neutron Activation Analysis (CNAA), and is most commonly used for uranium content analysis.


Fluorine Analysis

Fluorine analysis is a service that is offered by Centre for Neutron Activation Analysis (CNAA) and allows for the short-lived F-20 to be analyzed.


Gamma Counting

Analysis and counting of gamma-emitting radionuclides is a service provided through the Centre for Neutron Activation Analysis (CNAA) using HPGe detectors.


Hotcell Services

Nuclear Operations and Facilities is home to three independent hot cell facilities located on campus, which can be used for various nuclear, materials, environmental, and health applications.


Medical Isotope Production

MNR is one of the world’s leading suppliers of I-125, which is used in nuclear medicine for the treatment of various cancers. Other medical isotopes are produced at the McMaster Nuclear Reactor, along with various research and technical grade isotopes.


Neutron Diffraction

Neutron diffraction is a non-destructive technique that is used to probe the structure of materials at the atomic level. The sample is placed within a neutron beam and the angles at which the neutrons are scattered by the material are recorded and information is gathered.


Neutron Radiography

Neutron radiography is a non-destructive technique for photographing the interior structure of solid objects.


Nuclear Dating

Nuclear dating plays an important role for determining the age of geological samples. Both the 39Ar-40Ar method or Electron Paramagnetic Resonance (EPR) spectroscopy method are offered through MNR to age date important archaeological artifacts.


Post-Irradiation Examination

Many areas of Nuclear Operations and Facilities allow for post irradiation examination purposes to allow for in depth analysis to take place.


Prompt-Gamma Neutron Activation Analysis

A service offered by the Centre for Neutron Activation Analysis (CNAA), it is used primarily for non-destructive elemental composition analysis.


Radioisotope Development & Production

Radioactive isotopes are widely used in basic and applied science and engineering, most notably as environmental and industrial tracers, and for medical imaging procedures.


Short-Lived Neutron Activation Analysis

A neutron activation technique that can be used to quantify dozens of chemical elements including metals, non-metals and metalloids at the parts per million level. Available through the Centre for Neutron Activation Analysis.


Taylor Radiobiology Source

The Taylor Source is a unique large volume, high dose-rate Cs-137 source, commonly used to examine the effects γ-radiation on living systems.


Technical Services – Engineering Design and Fabrication

The Technical Services team provides essential engineering support for ancillary groups within Nuclear Operations & Facilities including Iodine-125 production, radioisotope development, quality assurance, and reactor operations.