A criterion for bistability of irradiation-induced voids

The number of equilibrium radii for irradiation-induced cavities is examined under the aspect that interactive correction terms to the void sink strength are taken into account. The result of these calculations is a criterion on the irradiation and materials parameters under which three equilibrium radii can occur. The system then has two stable radii separated by an unstable one. It is shown that this bistable cavity size distribution is possible only if the cascade collapse efficiency is within a narrow range of values. For the case of steel irradiated in a fast spectrum fission reactor it is exemplified that the incorporation of interactive void sink strengths does not amount to a simple refinement of the results obtained so far; it is demonstrated that drastic qualitative changes in the behaviour of the system may be observed. (orig.)