Comparative studies of brittle fracture mechanism for standard and reconstructed CT specimens made of VVER-1000 RPV materials

Abstract

Before 2002, SE(B) specimens were included in surveillance specimen sets for operating VVER-1000 reactors. The transition from SE(B) specimens to CT specimens in the fracture toughness tests is caused by the necessity to reduce the scatter and the conservativeness of results caused by the scale increase and the loading scheme. To make such a transition possible, SE(B) specimens were reconstructed into CT specimens. The comparative fractographic analysis of standard and reconstructed CT specimens after the fracture toughness tests shows that the crack initiation in both types starts from the “origin.” The types of “origins” and their ratios do not change, and the test results and the fractographic analysis data for standard and reconstructed CT specimens are described by one analytical dependence CTOD(CID) for each material and state.