Assessment of toughness and cracking in the heat-affected zone of light water reactor components

Basic investigations on the heat-affected zone (HAZ) of component weldments involving testing of simulated samples have provided information on the possible decrease of toughness and/or the susceptibility to cracking due to the thermal-mechanical history of the component. The different steel types are classified according to the embrittlement and cracking behavior. Outstanding problems concerning the real lower bound toughness properties, and the significance with regard to the integral resistance of the component lead to a requirement for optimization of manufacturing processes and the introduction of new developments. In parallel with these aspects is the need to evaluate the real safety margin by applying additional testing concepts in the framework of a Water Reactor Safety Research Program on ''Safety of Components.''