Testing needs for bcc materials in view of dynamic loadings in fusion reactors

Abstract The relevance, the testing needs and the evaluation methods for the dynamic material properties essential for structural design analysis with respect to the abnormal high-rate loading conditions in a fusion reactor are discussed. Emphasis is given to the dynamic fracture toughness and to bcc materials (like ferritic/martensitic steels, Mo or V-alloys) which exhibit brittle/ductile fracture transition temperatures. These increase with n-fluence and loading rate, as well as, in general, also with increasing specimen size and notch acuity. Aiming at realistic transition temperatures it is proposed therefore to systematically investigate the correlation between the results of pre-fatigued impact specimens (of standard and sub-size) and of dynamic fracture mechanics samples of proper dimensions instead of carrying out extensive standard Charpy impact tests.