Direct measurement of reactor pressure vessel steels fracture toughness: Master Curve concept and instrumented Charpy-V test

One of the key issues concerning the structural integrity of reactor pressu re vessel is the effect of neutron irradiation on the material fracture tou ghness. At present, this is achieved indirectly by means of correlation bet ween Charpy and fracture toughness due to neutron irradiation. The uncertai nties associated with this indirect determination have increased the need f or a direct measurement of the fracture toughness. Taking into account that the surveillance capsules include Charpy-V specimens, recent investigation s are focused on the determination of the fracture toughness using this typ e of geometry. This paper presents two different ways to obtain fracture to ughness from Charpy-V specimens: instrumented Charpy-V tests and static fra cture toughness tests (three-point bend) applying the "Master Curve" concep t. The two methodologies are applied to reactor pressure vessel steels in t he unirradiated condition. (C) 2000 Elsevier Science Ltd. All rights reserv ed.