The stress-corrosion-cracking model for high-level radioactive-waste packages

A stress-corrosion cracking (SCC) model has been adapted for performance prediction of high-level radioactive-waste packages to be placed in the proposed Yucca Mountain repository. For these waste packages, the outer barrier material is the highly corrosion-resistant alloy UNS-N06022 (alloy 22). The tensile stress is principally from weld-induced residual stress. To account for crack propagation, the slip dissolution/film rupture (SDFR) model is adopted to provide mathematical formulae for prediction of the crack growth rate. Once the crack growth rate at an initiated SCC is determined, it can be used to determine the time to through-wall penetration for the waste package. This paper presents the development of the SDFR crack growth rate model. A seismic-damage-related SCC crack opening area density model is also briefly described.