Flux dependence of cluster formation in neutron irradiated weld material

SANS results for an RPV weld material irradiated at two different neutron fluxes up to the same neutron fluence will be presented. We have observed a remarkable effect of flux on the size of irradiation-induced clusters. A rate theory model is applied in order to give a tentative explanation for the findings. Interestingly, the mechanical properties do not show a corresponding flux effect. The results will be faced with observations for another RPV steel exhibiting a different behaviour.