The Lifetime and Failure Strain Prediction of Zircaloy-4 Cladding Loaded Under Loca-Similar Temperature Ramp Conditions

Publisher Website
Google Scholar
Abstract
The life fraction rule is applied to predict the time to failure of internally pressurized Zircaloy-4 cladding tubes subjected to temperature ramps similar to those expected in a hypothetical loss-of-coolant accident. For given loading conditions, the calculations are solely based on data from uniaxial stress rupture tests. No fitting procedure is involved in the comparison between prediction and results of burst tests. This evidently is an advantage of the present procedure. The agreement between the results of calculations and experiments is good. A modified Monkman-Grant (MMG) relationship, which connects the lifetime with the minimum creep rate and the strain to failure, is used to predict the failure strain of Zircaloy-4 cladding subjected to temperature ramps. This problem turned out to be more complicated than the prediction of lifetime. Contrary to the latter, due to the anisotropy of strain, data from burst experiments enter into the failure strain calculations. Thus the applicability of this method in the present form is restricted to particular loading conditions. However, considering the complexities of the problem, the agreement between experiments and calculations is encouraging.