Reactor Water Environmental Fatigue
Existing nuclear plants were designed based on fatigue data obtained entirely in air environments. We now seek to extend the life of these plants, recognizing that many conservatisms were included in the fatigue stress calculations, stress concentration factors and lumped transients. Since we know how these plants were operated, we can quantify the cyclic rates and coolant chemistry. This makes it feasible to use environmental fatigue life evaluation technology which takes credit for the reduced corrosion fatigue damage which occurs during more rapid transients and for reduced dissolved oxygen levels which produce lesser corrosion fatigue damage in carbon and low alloy steels. Accordingly, the use of Fen environmental fatigue life reduction factors which depend on the cyclic rates, coolant chemistry and temperature are quite useful for evaluating the safe fatigue life of aging plants and for license renewal.