Implementation of results from MPA reactor safety research in the integrity assessment of German reactor pressure vessels

The safety analysis of a reactor pressure vessel is performed on a fracture mechanics basis. The paper introduces methods to determine fracture toughness values from small scale specimen testing which can be used to predict crack initiation for large structures even under complex loading conditions. The fracture mechanics concepts were verified for crack initiation and crack arrest. Taking the multi-axial stress state into consideration also the amount of stable crack growth could be determined in case of thermal shock loading. It could be confirmed that the fracture mechanics concept of the Code, based on the reference temperature RT^DT describes the material behavior conservatively and can be applied to unirradiated as well as irradiated material states. © 1999 Elsevier Science S.A. All rights reserved.