Actual Problems of Structural Integrity Assessment of WWER-1000 Pressure Vessel Internals

The problem of numerical prediction of the process of radiation swelling in internal elements for assessment of structural integrity and prolonging the lifetime of the WWER-1000 reactors is quite actual. The critical element is core baffle, which is operating under high gradients of neutron irradiation and temperature. The influence of features of various fuel campaigns and their sequence on the distribution and the maximum value of radiation swelling, as well as, on stresses and distortions in the baffle after long-term service. The consequences of a possible decrease in the efficiency of cooling on the external surface of the baffle in the event of a gap closing between the barrel and the baffle due to radiation swelling or prediction tolerances are reviewed. According to result of modeling the recommendation for numerical assessment of residual life of internal baffle WWER-1000 reactor are formulated.