Experimental and theoretical study for the evaluation of the residual life of the primary circuit of LWR's

A research activity, aimed at the evaluation of the degree of deterioration of the integrity and at the estimation of the residual life of a nuclear structure is going on at the CC-JRC of Ispra. Two lines of research have been followed in the last five years: set up of a methodology and implementation of a numerical code for the estimation of the probability of failure of pressure vessels; and on-line monitoring of fatigue crack formation and propagation on scale 1:15 models of vessels. Paper summarizes the main results of these activities and outlines the follow-up: a set of experiments on scale 1:5 cladded models of PWR vessels in SA 508 and SA 533 steels