Iron matrix effects on cluster evolution in neutron irradiated reactor steels

The present model of vacancy cluster evolution in bcc iron under neutron irradiation, which is based on rate theory according to Odette, can be adjusted with respect to volume fraction and mean radius of vacancy clusters obtained by means of SANS measurements on a low-copper iron alloy. The values of the specific surface energy of clusters and the dislocation density taken to adjust the model are both reasonable. The expectation that the surface energies for the two dose rates considered should agree is best fulfilled, if the real solution model for vacancies in iron is taken into account.