Quantitative modelling of swelling in M316 steel

The chemical rate theory is widely used to describe the microstructural evolution in a material during irradiation. We describe recent improvements to the theory that increase its predictive capability. The incubation dose prior to the onset of void swelling is modelled by allowing partition of the gas between the various sinks in the microstructure. New dislocation and void sink strengths have been derived incorporating the field effects. These improvements to the theory have been incorporated into a new FACSIMILE computer code designated VS5. The new code has been successfully employed to model void swelling during HVM, VEC and fast reactor irradiation of 316 steel. (orig.)