Prediction Of Long-Term Creep Properties Of Zirconium-2.5 % Niobium Alloy Using Wilshire Method

Zirconium-2.5 % niobium alloy, used as a pressure tube material in pressurized heavy water reactors, have to experience extreme stress, temperature, and radioactive conditions to serve within the designed dimensional tolerance limit. Prolonged duration under high stress and high temperature causes the creep deformation, ultimately leading to deformation beyond the permitted limit or interference with other components, or both. Hence, a priori using particular material for a specific application, mechanical testing has to be done to investigate its deformation behavior. However, creep tests of material can last from a few hours to several months or even years. The cost of testing the material can eventually impact the cost of the component. Instead of carrying out long-term creep tests, an extrapolation technique named the Wilshire method is applied to predict the creep behavior of the material under any given test conditions. This method is also capable of reconstructing the complete creep curve using the data from accelerated creep tests. Such an approach can drastically scale down the cost and time required for the long-term creep tests. In the present study, zirconium 2.5 % niobium alloy, which is used as pressure tube material in pressurized heavy water reactors, is employed as a test material for the analysis using the Wilshire method.