TESTS ON LARGE-SCALE LMFR PIPING .1. CRACK RESISTANCE PROPERTIES OF THROUGH-CRACKED STRAIGHT 700-MM NOMINAL DIAMETER PIPES TESTED UNDER BENDING AT AMBIENT-TEMPERATURE AND 550-DEGREES-C

Knowing the crack resistance properties of a structure is essential fo r fracture mechanics safety analyses. Considerable attention has to be given in many cases to the through-wall case, since this is generally believed to be the controlling case with regard to complete pipe fail ure. Within a cooperative fracture mechanics programme of Electricite de France (EdF), Novatome and Siemens/KWU, bending tests with monotono usly increasing load on circumferentially cracked straight pipes of ty pical liquid metal fast reactor (LMFR) main piping dimensions were per formed. In this paper a summary report is given on crack resistance cu rves based on the crack tip parameters delta, J and J(M). The data are compared with those of C(T) specimens. The experiments have demonstra ted an enormous potential for stable crack extension under global bend ing which is a typical loading for LMFR piping structures. The results of checking the transferability of laboratory specimen crack growth c haracteristics to the cracked pipes on the austenitic stainless steel 316 L demonstrate that the fracture mechanics concept for a reliable t ransfer of crack resistance data from small specimen geometries to lar ge structures needs further qualification for high toughness materials .