Methodology of Including Spatial Nonuniformity of Material Properties in the Brittle Fracture Resistance Calculation for WWER-1000 Reactor Pressure Vessels. Part 1. Theoretical Analysis

The paper addresses the main methods of predicting the temperature dependence of fracture toughness. The authors have analyzed a system of margins which have to be introduced in order to adequately and conservatively predict this dependence using the results of testing surveillance coupons. A methodology is put forward for determining a margin for spatial nonuniformity of properties of the reactor pressure vessel material, which is based on simultaneous deterministic and probabilistic calculations of brittle fracture resistance of a reactor pressure vessel.