IAEA coordinated research project on master curve approach to monitor fracture toughness of RPV steels; Final results of the experimental exercise to support constraint effects

Nanstad, R.*; Brumovsky, M.*; Callejas, R.*; Gillemot, F.*; Korshunov, M.*; Lee, B.*; Lucon, E.*; Scibetta, M.*; Minnebo, P.*; Nilsson, K.-F.*; Miura, Naoki*; Onizawa, Kunio ; Planman, T.*; Server, W.*; Burgos, B.*; Serrano, M.*; Viehrig, H.-W.*

IAEA has developed a coordinated research project (CRP) to evaluate various issues associated with the fracture toughness Master Curve for application to light-water RPVs. Topic Area 1 of the CRP is focused on the issue of test specimen geometry effects, with emphasis on determination of reference temperature T with the pre-cracked Charpy (PCC) specimen and the bias effect on T. Participating organizations for the experimental part of the CRP performed fracture toughness testing of various steels with various types of specimens under various conditions. Results from fracture toughness tests are compared with regard to effects of specimen size and type on the T. It is apparent from the results that the bias observed between the PCC specimen and larger specimens for Plate JRQ is not nearly as large as that obtained for other steels (-11C to -45C). This observation is consistent with observations in the literature that show significant variations in the bias that are dependent on the specific materials being tested.