Institute of Nuclear Engineering

The SLOWPOKE Laboratory

The SLOWPOKE Laboratory

Image du SLOWPOKEThe main piece of equipment is the SLOWPOKE nuclear reactor. This small pool-type reactor operated from 1976 to 1997 with the original fuel, 1 kg of 93% enriched uranium. In 1997, thanks to an NSERC Major Installation Grant, the reactor was refuelled with 5 kg of uranium enriched to 20% in U-235. At full power of 20 kW, the neutron flux in the five inner irradiation sites of the reactor is 1012 /cm2/s. The power and the neutron flux are highly reproducible and the reactor can operate unattended for up to 24 hours. It is used mainly for neutron activation analysis and for the production of radioactive tracers. For irradiating materials, access to the neutrons is through pneumatic rabbit systems. One of the six rabbit systems is automated and can be programmed to send a set of samples directly from reactor to detector.

Instrumentation is also available for training nuclear engineering students in reactor kinetics.

Image du coeurThe neutron activation analysis laboratory adjacent to the reactor has four state of the art gamma-ray spectrometers with high-resolution germanium semiconductor detectors and mechanical sample changers.

Personnel

  • Cornelia Chilian, director of the SLOWPOKE Laboratory
    • neutron activation analysis
    • radioactive tracers
    • environmental radioactivity
  • Gregory Kennedy, associated professor
    • neutron activation analysis
    • radioactive tracers
  • Rahma Kada, research associate
    • neutron activation analysis

Research Program

1. Neutron Activation Analysis (NAA)

The Laboratory is used primarily for neutron activation analysis, which is a type of non-destructive chemical analysis used for measuring the concentrations of chemical elements in solids et liquids. When a substance is irradiated with neutrons it becomes radioactive and after it is removed from the reactor, atoms of the different elements emit gamma-rays which are detected.

Although NAA is a well established and reliable technique, the personnel of the SLOWPOKE Laboratory are looking for ways to improve it. We are currently working on a new standardization method which should improve the accuracy of the chemical analysis and we are developing gamma spectrometry software to improve the sensitivity and precision.

The users of the Laboratry come from Ecole Polytechnique, the University of Montreal and six other Quebec universities. The following examples illustrate the numerous areas of research benefitting from neutron activation analysis:

  • Geochemistry - for the determination of rare-earths and platinum group elements which yield information on the formation of rocks and mineral deposits.
  • Materials science - for verifying the composition of new materials.
  • Archaeology - the chemical composition of ancient metal, ceramic and lithic objects is used to determine their provenance.
  • Medicine - studies on the toxicity of trace metals.
  • Environment - studies of heavy metal pollution in air and water, emissions of metals from the combustion of petroleum products. The results of our major study on atmospheric emissions from automobiles were instrumental in convincing the government to approve a new gasoline additive, less polluting than previous additives, which will significantly improve the quality of the air in our cities.

2. Radioactive Tracers

An extensive collaboration has been established between the SLOWPOKE Laboratory and the chemical engineering department for the production and use of radioactive tracers for the study of flow dynamics in multiphase chemical reactors. For the measurement of residence time distributions, solids and gases are activated in the SLOWPOKE reactor and injected in the system under study and their movement is followed with several NaI detectors.

In a number of ongoing collaborations in medicine and pharmacy, radioactive tracers are used in animals and humans for the study of the dissolution of medication in the digestive system and distribution to various organs.

3. Environmental Radioactivity

Gamma-ray spectrometry are used to measure radionuclides in soil, water, building materials and food.

Cooperation with Industry

A major part of the funding of the Laboratory is derived from contracts with industry:

  • The petrochemical and metallurgical industries use NAA to verify the composition of their plastics and alloys.
  • The wood products industry uses NAA to measure the retention of chemical preservatives.
  • The toxic waste disposal industry uses the Labortory to identify and quantify radioisotopes in suspected radioactive substances.

For more information on the neutron activation analysis service, contact:

Address to send samples to be analyzed:
  • École Polytechnique
    attn. Cornelia Chilian
    2900 Édouard-Montpetit
    Montréal, Québec
    Canada H3T 1J4

École Polytechnique SLOWPOKE page

Consult the "Répertoire des expertises et des unités de recherche" of Polytechnique to know more about the SLOWPOKE laboratory.

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