Improvement of LWR pressure vessel steel embrittlement surveillance

This progress report highlights selected new accomplishments pertinent to three specific lines of activities encompassed by the considered cooperative programs. Recent progress at the VENUS engineering mock-up is reviewed. This includes final conclusions for the uranium-fuelled core represetative of beginning-of-life PWR configurations as well as preliminary results for a new mixed-oxide uranium-plutonium low leakage core. The program of in-vessel and ex-vessel neutron dosimetry performed at the DOEL power plants is outlined, and the trends of theory-versus-experiment comparisons are summarized in light of the overall reactor physics surveillance benchmarking effort. Addressed finally are the development and critical evaluation of metallurgical embrittlement trend curves, an effort born out of the need to understand better the mechanical properties of BR3 reactor beltline materials subsequent to a March 1984 pressure vessel annealing