SANS characterization of precipitates in irradiated (RPV) steels

In this proposal, we ask for beam time to finish the study of the effect of dose radiation on the mechanical behaviour of the Reactor Pressure Vessel (RPV) Steel used in the nuclear reactor under construction Atucha II in Argentina. RPV is a critical component in any reactor since it cannot be replaced during its whole lifetime. In service, exposure to neutrons degrades it. Irradiation damage produces precipitates due to neutron-induced displacements. We have studied the dose-rate effect on RPV embrittlement due to the precipitates. Size and distribution determine the hardening and embrittlement of the steel. We intend to resolve the morphology of the precipitates in a more representative area and with less aggressive preparation (that may change the magnetic and structural properties locally) of the sample than with TEM and to perform measurements under a magnetic field.