Strength of the WWER-type reactor vessel in accidental operating conditions

The method of calculating resistance of the WWER-type reactor vessel to brittle destruction under conditions of accidental cooling, is suggested. A crack in the inner vessel surface is taken for the initial defect. The task is solved for various crack parameters and given loading conditions. It is shown that force criterion of the linear elastic destruction mechanics should be used when calculating the brittle strength of a reactor vessel in accidental situations. The method proposed permits to analyze the most complex situation i.e. accidental regime as regards the combination of loading, metal properties, the possible position of defects, which is difficult to realize using the normative approach alone. The analysis of cracks in a wide range of depths permits to determine the critical size of the initial defect and on that base to conclude on the possible dangerous cracks in the vessel and on the necessary quality of defectoscopic control of produced and operating WWER vessels