UNIFORM CORROSION OF MODEL FECRAL ALLOYS IN LWR COOLANTS

摘要

The ferritic FeCrAl alloys are being considered as one of the premier and near-term candidates to replace Zr-based alloys as fuel cladding in LWRs with the goal of enhancing safety margins under severe accidents. Even though Fe-based alloys have a higher thermal neutron absorption cross section, austenitic stainless steels were used in the past in commercial LWRs into the 1980s. The FeCrAl alloys exhibit better neutron economy compared to these historic cladding materials since they do not contain any Ni. Detailed neutronics analysis of this class of cladding materials has been reported elsewhere. Many studies related to optimized alloy development, tube fabrication, irradiation effects, and environmental response are currently underway. Within the last area, high-temperature steam oxidation has received ample attention while corrosion under normal operating conditions requires continued investigation. In this transaction the results from immersion testing of model FeCrAl alloys in LWR coolant environments is summarized.