Correlation of Irradiation-Induced Transition Temperature Increases from Cv and KJc/KIc Data.

摘要

Reactor pressure vessel (RPV) surveillance capsules contain Charpy-V (Cv) 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 (Cv) tests. Since the ASME K(Ic) and K(IR) reference fracture toughness curves are shifted by the delta T from Cv, 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 this behavior, comparisons of delta T's defined by elastic-plastic fracture toughness and Cv tests have been made using data from RPV base and weld metals in which irradiations were made under test reactor conditions.