Calculation of crack size in WWER reactor vessel

The technique for calculated substantiation of permissible sizes of cladding semielliptical crack in WWER vessel is presented. The most loaded hydrotest regime and violations in the system of boron control are chosen as calculated regimes. The history of vessel cyclic loading and changes of mechanical properties of vessel material in the process of reactor exploitation were taken into account during calculations. The critical crack depth is determined depending on reactor service life. The choice of safety factor coefficient to substantiate permissible crack sizes is suggested. The final permissible crack depth is 9 mm