THE EFFECTS OF TRANSMUTATION PRODUCTS ON THE RADIATION-INDUCED SWELLING OF AL2O3 AND MGAL2O4

In the absence of a high flux, fusion neutron source the effects of the major transmutation products hydrogen, helium and carbon on the swelling of polycrystalline Al2O3 and MgAl2O4 have been simulated for damage doses up to 20 dpa within the temperature range 535-1080 K. The samples were pre-implanted with H, He and C and subsequently irradiated with 4 MeV argon ions to give a transmutation product to damage dose ratio of 100 appm/dpa. The triple implants produced only a small increase in the volume swelling of alumina which did not exceed 15% of the swelling in non-implanted material under any irradiation conditions. The swelling in alumina varied as the damage dose to the power 0.36 for irradiation temperatures below 1080 K. After approximately 1 dpa at 1080 K the exponent changed to 0.56 consistent with void swelling. In the case of MgAl2O4 spinel the triple pre-implants produced a large increase in volume swelling approximately doubling that for non-implanted spinel under all irradiation conditions.