Correlation of C(v) and K(Ic)/K(Jc) Transition Temperature Increases Due to Irradiation.

摘要

Reactor pressure vessel (RPV) surveillance capsules contain Charpy-V (C sub v) specimens, but many do not contain fracture toughness specimens; accordingly, the radiation-induced shift (increase) in the brittle-to-ductile transition region (Delta T) is based upon the Delta T determined from notch ductility (C sub v) tests. Since the ASME K sub Ic and K sub IR reference fracture toughness curves are shifted by the Delta T from C sub v, assurance that the Delta T does not underestimate Delta T associated with the actual irradiated fracture toughness is required to provide confidence that safety margins do not fall below assumed levels. To assess the behavior, comparisons of Delta T's defined by elastic-plastic fracture toughness and C sub v tests have been made using data from RPV base and weld metals in which irradiations were made under test reactor conditions. As well, comparison of Delta T's at various index levels gives indications of C sub v, K sub Jc and K sub beta c curve shape change due to irradiation. Lastly, comparisons between measured Delta T(C sub v) and values using various correlations or models are also made.