The influence of cascade damage on irradiation creep and swelling

The irradiation of metals by fast neutrons or heavy ions produces displacement cascades. In many metals a substantial fraction of these cascades collapse to form vacancy loops. In this paper the effect of these vacancy loops on irradiation swelling and irradiation creep is examined. It is found that the presence of the vacancy loops reduces the effective displacement damage rate and consequently the irradiation creep and swelling rates are less than they would otherwise be. In addition it is shown that irradiation creep mechanisms which depend on the thermal emission of vacancies from vacancy loops are untenable. (Auth.)