Royal Military College of Canada

Energy and Nuclear Science

Radiation Processing and Effects of Radiation on Materials

By: Dr. Hugues W. Bonin & Dr. Van Tam Bui

At first, the adhesive properties of polymers such as various types of epoxies were investigated, using the reactor as a source of intense radiations in order to determine their effects as a function of the dose received.. It was observed that for some epoxies, the radiations actually strengthened the bonding between the adhesive and the flat surface of aluminum cylinders held together by the epoxies. The effects of the radiations, consisting of a mixed field of thermal and fast neutrons, gamma rays, energetic electrons and protons, amounted to two main phenomena, cross linking of molecules promoting increased adhesive strength, and chain scission, resulting in weakening of the bonds.

The research then continued in several directions. The effects of radiations on polymers continued using more epoxies, including the case when the samples were irradiated during curing time. An advanced adhesive was then investigated more closely: the Poly(Ether Ether Ketone) (or PEEK), and it was found that this new polymer was among the best of the adhesives in terms of re4sistance to radiations and could well serve for space applications and in the nuclear industry. This research is presently in the investigation of several polymer-fibre composite materials.

Aluminum Cylinders

Set of Aluminum Cylinders Glued with Epoxy Adhesive Being Irradiated.

A second direction of the research consists of using the radiations produced by the SLOWPOKE-2 reactor to neutralize plastic explosives that have expected their "shelf life". The disposal of these explosives is a problem for the Canadian Forces as important quantities of these nitrocellulose-based explosive materials are used for ammunition and shell rounds, as the method currently used is to detonate this material in open fields. Non explosive samples of various grades of nitrocellulose were irradiated in the reactor pool and analysed subsequently, and compared to non irradiated samples. Methods such as Fourier Transform Infrared (FTIR) analysis and Gel Permeated Chromatography (GPC) were used to demonstrate that the radiations were a very efficient tool to denitrate the nitrocellulose molecules. This research is presently at the stage of the design of an irradiation facility for use by the Canadian Forces.

A third direction of this research consists in designing a container for the long-term storage of spent nuclear fuel, and high, intermediate and low-level radioactive wastes, using polymer-based composite materials for the fabrication of the container. This research is further subdivided into two separate areas: the container for the spent nuclear fuel and the high level radioactive wastes, and another container for intermediate and low level radioactive wastes. The ultimate disposal conditions for the spent nuclear fuel and the high level radwastes are much more demanding, since the present proposal is for storing the containers deep underground in cavities carved in granitic rock formations within the Canadian Shield. The container must remain leak tight during at least five hundred years, and much longer. It must resist not only the radiations still emitted by the radioactive material, but also the chemical aggression from contact with the underground water, and it must withstand the large hydrostatic pressure from the rock matrix and the high temperature from the heat released by the decaying radioactive atoms. The design problem for the container intended for the disposal of the intermediate and low level radioactive wastes is also quite challenging. The disposal approach here is for surface or shallow storage of the containers which must also remain leak tight for centuries. Although the radiation fields and the heat generated by the stored radioactive wastes are much less than those from high level wastes, the resistance of the container wall material to prolonged contact with aggressive chemicals must be assured for hundreds of years, and the cost of the container becomes important since the volumes of intermediate and low level radioactive wastes are significantly larger than that of the high level wastes.

An interesting spin-off of this research has been a related research project on the determination of the radiation doses received by the samples positioned in the reactor and in the pool during their irradiation time. In this work, several projects were carried on and in experimental particle flux and dose measurements that were supplemented by the simulation of the reactor and pool using computer codes such as MicroshieldTM and locally written softwares.

Container for the Long-Term Disposal

Container for the Long-Term Disposal of Spent CANDU Fuel Bundles.

(From: "Environmental Impact Statement on the Concept for Disposal of Canada's Nuclear Fuel Waste", Document AECL-10711 & COG-93-1, Atomic Energy of Canada Ltd., Sept. 1994)

This research has generated several projects that supported the teaching in the Chemical and Materials Engineering and the Honours Chemistry undergraduate programs, and the M.Eng. programs. in Nuclear Engineering and in Chemical and Materials Engineering These projects are listed below:

Bachelor of Engineering, Chemical and Materials Engineering

(Courses CME/CMF417 Design Project and SCE420 Senior Project):
  • 1992-1993: "Damage Analysis of Polymer Composite Epoxies in High Radiation Environments"
  • (Student: H.M. Pak)
  • 1993-1993: "Damage Analysis of Polymer Composite Epoxies in Environments of High Radiation"
  • (Students: D.P. Arnold, D. Chambers, and J.D. Schwindt)
  • 1994-1995: "Irradiation of Low-Nitrogen Content Nitrocelluloses", (Students: B. Brettschneider and C.A. Dann)
  • 1994-1995: "Radiation Effects on Polymer Composite Epoxies" (Student: P.E. Poirier)
  • 1995-1996: "Radiation Effects on Polymer Composite Epoxies" (Student: H.C. Harris)
  • 1996-1997: "Design of a Container Made of Composite Material for the Long-Term Disposal of Spent Nuclear Fuel" (Students: A.R. Davey, T.D. Douglas, C.C.S. Duriez and G.B. MacGregor)
  • 1996-1997: "Neutralization of Spent Plastic Explosives by Neutrons and Gamma Radiations", (Students: M.L. Bickerton & D.P. Murphy)
  • 1996-1997: "Radiation Effects on the Curing of Epoxy Resins" (Students: P.D. Duncan and M.A. Lajoie)
  • 1998-1999: "Design of a Container Made of Composite Material for the Long-Term Disposal of Spent Nuclear Fuel" (Students: M.R. Dunning, K.R. Hoffman and C.A. McKenna)
  • 1998-1999: "Radiation Effects on Multi-Compound Polymer Adhesives" (Student: A. M. Gallagher)
  • 1999-2000: "Radiation Effects on Epoxy-Based Composite Materials" (Student: S.K. Power)
  • 2000-2001: "Design of an Irradiation Facility for the Destruction of Spent Plastic Explosives" (Students : J.O.A. Kim, M. L'Italien, E.L. Nault and C. Prechotko) (in progress)
  • 2000-2001: "Radiation Effects on Epoxy-Based Composite Materials" (Students: D.P. Francis and M.K. Grandlund) (in progress)

Master's of Engineering (Nuclear Engineering) theses:

  • J.Y.S.D. Pagé, "Neutron and Gamma Radiation Effects on the Viscoelastic Behaviour of Poly(Aryl Ether Ether Ketone)", 1997.
  • G. B. Lamarre, "Experimental and Computational Determination of Radiation Dose Rates in the SLOWPOKE-2 Research Reactor at the Royal Military College of Canada / Collège militaire royal du Canada", 1999.
  • Capt. K. M. Heppell-Masys, "Neutralization of Spent Plastic Explosives by Neutrons and Gamma Radiations"; these to be submitted September 2000.
  • Lt(N) M. Walker; "Design of a Container made of Polymer-Based Composite Material for the Long-Term Disposal of Intermediate and Low Level Radioactive Wastes" (in progress).
  • MCpl I. Miedema; "Design of a Container made of Polymer-Based Composite Material for the Long-Term Disposal of Spent Nuclear Fuel and High Level Radioactive Wastes"; (in progress).

Sample Publications:

  • H.W. Bonin, V.T. Bui, H. Pak, E. Poirier & H. Harris, "Radiation Effects on Aluminum-Epoxy Adhesive Strength", J. of Appl. Polymer Science, Vol. 67, 37-47 (1998).
  • V.T. Bui, H.W. Bonin, D. Rhéaume, H. Pak, D.P. Arnold, D. Chambers and J.D. Schwindt, "High Radiation Effects on Epoxy Adhesives", Proc. 35th IUPAC Int. Symp. On Macromolecules (MACROAKRON), Akron, Ohio, U.S.A., 11-15 July 1994, p. 1047.
  • K. Heppell-Masys, H.W. Bonin, V.T. Bui, M.L. Bickerton & D.P. Murphy, "Neutralization of Spent Plastic Explosives by Neutrons and Gamma Radiations", Proc. 18th Ann. Conf. Of the Canadian Nuclear Society, Toronto, Ontario, Canada, 8-11 June 1997 (Session 4C).
  • J.Y.S.D. Pagé, H.W. Bonin & V.T. Bui, "Effects of Neutron and Gamma Radiation on the Viscous Behaviour of Semi-Crystalline Polyetheretherketone (PEEK)", Proc. 18th Ann. Conf. Of the Canadian Nuclear Society, Toronto, Ontario, Canada, 8-11 June 1997 (Session 2B).
  • G.B. Lamarre & H.W. Bonin, "Experimental and Computational Determination of Radiation Dose Rates in the SLOWPOKE-2 Research Reactor at the Royal Military College of Canada", Proc. 20th Ann. Conf. Of the Canadian Nuclear Society, Montréal, Québec, Canada, 30 May- 2 June 1999, Session 2A.
  • H.W. Bonin & V.T. Bui, "High Polymer-Based Composites for Spent Nuclear Fuel Disposal Containers", Proc. 6th Int. Conf. On CANDU Fuel, Niagara Falls, Ontario, Canada, 26-29 Sept. 1999, Session 2C.
  • H.W. Bonin & V.T. Bui, "Composite Materials in Nuclear Industry: Specific Applications", Proc. 7th Annual International Conference on Composites Engineering", Denver, Colorado, U.S.A., 208 July 2000 (Invited).