Leakage and rupture of damaged tubes

This book presents the manufacturing properties of metal tubes and the particularities of resistance calculation, tensile strength criteria in linear and non-linear rupture mechanics, fragile, quasi-fragile and ductile rupture resistance methods. It examines the possibilities of calculation of nuclear power plant pipes according to the 'leakage before rupture' design basis concept. In general, the defects introduced during manufacturing, construction or repair, or created during the operation and leading to fissures occurrence, are potential sites for tubes rupture. The in-service experience of nuclear plant tubes with various diameters shows that their rupture with formation of superficial cracks (without leakage) and with formation of penetrative cracks (with leakage) are proven facts. In the case of occurrence of continuity defects, considered as cracks, it is necessary to consider all steps of crack growth in order to answer the following questions: is it possible to observe a stable growth for a penetrative fissure and thus to have a leakage before the definitive rupture of the tube?; what are the critical dimensions of a fissure and what is its sub-critical growth value?; how to define the dimensions of an admissible fissure in the case of leakage, etc. (J.S.)