A kinetic rate theory model was presented which included the formation of cascade-induced clusters. A comparison of the model with ion irradiation data on V revealed the effects of He generation and cascade-induced interstitial and vacancy clusters upon microstructure evolution. The model was based upon a simplification of hierarchical rate equations for the clustering of He bubbles, immobile vacancy clusters, glissile interstitial clusters, sessile dislocation loops, as well as precipitates and grain boundaries. The model showed that the transport of He to dislocation bubbles and grain boundaries was highly transient because of a coupling of the nucleation and growth modes of bubble evolution. The agglomeration of He in vacancy clusters was shown to reduce the excess vacancy flux to growing matrix- and precipitate-affixed bubbles. The direct formation of vacancy and interstitial clusters in cascades reduced the growth rate of bubbles, and led to the enhanced nucleation of matrix bubbles. In addition to the dislocation and production bias mechanisms, a new mechanism of so-called He nucleation bias was shown to exist at high He generation rates.

Comparison of a Microstructure Evolution Model with Experiments on Irradiated Vanadium. S.Sharafat, N.M.Ghoniem: Journal of Nuclear Materials, 2000, 283-287, 789-93