Shear Strengths of Copper/Insulation Interfaces After In-Core Reactor Irradiations

The adhesive shear strengths of copper/insulation interfaces were evaluated using a novel specimen design in which thin copper foils were embedded in laminate structures. In each instance, the copper surface was either chemically or physically treated prior to laminate fabrication. Once produced, the specimens were subjected to in-core reactor irradiations providing total radiation doses of 10, 22, and 100 MGy with a gamma/neutron ratio representative of conditions in fusion systems. Post-irradiation short-beam-shear tests indicate that the best-performing copper treatments retain 65-70% of their original interfacial shear strength at 76 K after receiving a total dose of 100 MGy. Previous findings showed that the initial adhesive strength could be improved through the use of copper surface treatments, and these results confirm that the copper/insulation interface remains strong after exposure to high-radiation environments.