Evaluation of off normal temperature events in stored nuclear fuel cladding on storage limits utilizing a modified dating code

Abstract

The purpose of this study was to utilize a modified DATING code to evaluate the effects off normal temperature conditions occurring during dry storage would have on allowable storage limits for Zircaloy cladding. Towards this, Zircaloy creep tubes were used to perform creep studies in a temperature range of 300-500⁰C with an applied stress range of 40-65 MPa. This allowed for the development of updated creep rate equations with the forms utilized in past studies by Mayuzumi and Matsuo to be fit. These fit equations along with the original mechanistic creep equations from the DATING code were used to evaluate the effects of off normal temperature events ranging from 10-100⁰C beginning at points in the fuels lifetime ranging from 5%-75% of the expected life time of 40 years. The results of this evaluation were that while differing allowable limits are found using the original rate equations and the equations fit to this studies data both cases show no noticeable effect on the allowable limit.