Experiments confirming applicability of the ‘leak before break’ concept for the International Thermonuclear Experimental Reactor

The paper presents the results of experiments carried out to study the fatigue development of surface flaws in welds in ductile steel pipes of diameters 76.3 and 101.6 mm and the possibility of detecting leaks through through-wall cracks in such pipes. It is shown that the experimentally determined character of the postulated surface flaw growth, its growth rate and the intensity of leaks do not contradict the data on calculations performed to justify the applicability of the ‘leak before break’ (LBB) concept for pipelines of the cooling system of the International Thermonuclear Experimental Reactor (ITER). It is also shown that the sensitivity of leak detection by the acoustic emission method meets the requirements of the Siemens calculation procedure. It is concluded that it is possible to apply the LBB concept to pipelines of the ITER’s heat transport system including pipes of diameter more than 75 mm.