Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Neutron irradiated reactor pressure vessel steel of two different Cu contents exposed to isochronal post-irradiation annealing treatments at stepwise increasing levels of temperature have been investigated. Results of small-angle neutron scattering experiments are reported and compared with the respective unirradiated and as-irradiated conditions. Volume distributions of scatterers and ratios of total to nuclear scattering intensities (A-ratio) were calculated from the measured differential macroscopic scattering cross sections. Finally, total volume fractions of scatterers, peak radii of the volume distribution and partial information on the composition of scatterers were extracted and discussed as a function of annealing temperature. Our measurements indicate that there is a temperature regime characterized by essentially complete dissolution of the irradiation-induced Cu-enriched clusters and another temperature regime characterized by a competition of dissolution and coarsening. An Arrhenius type of behaviour and a remarkable reversibility of the irradiation-induced cluster distribution are observed in the complete dissolution regime.