Effect of heavy high-energy gas ions on mechanical properties of zirconium

To simulate radiation damage from fission fragments at inner surface of WWER fuel cans zirconium specimens were irradiated with 460 MeV Ar and 230 MeV ions. Irradiated specimens were subjected to tensile testing. Yield strength was found to increase after irradiation. Microscopical examination of specimens deformed by 3% revealed cracks in a surface layer. The brittleness of the layer occurs due to implanted ions, precipitation of fine gaseous bubbles and radiation defects. Crack propagation in a surface layer can be the first stage of damageing resulted from fuel-can interactions. 14 refs., 2 figs., 2 tabs