Air oxidation of Zircaloy-4 in the 600–1000°C temperature range: Modeling for ASTEC code application

Qualitative analysis of Zircaloy‐4 cladding air degradation in O2–N2 mixtures at high temperature

“…A comprehensive description of the kinetic transition appearing during Zry‐4 oxidation (without nitrogen) based on Mampel's model can be found in . Similar mathematical calculations could be applied to explain the shape of the kinetic curves under a 20% O 2 –80% N 2 mixture assuming that (i) the post‐transition regions (large cracks zones) appear at random at the sample surface just as nuclei with a nucleation frequency depending on temperature, oxygen, and nitrogen partial pressures (this will be discussed later in Section ), alloy composition, etc.…”

“…The purpose of researches made in this field is to implement a model which could represent what happens in air ingress situations and consequently to better anticipate consequences and circumstances of such accidents .…”

Review on Core Degradation and Material Migration Research in Light-Water Reactors

“…It has been applied to serial analyses of experiments, severe accident sequences, and evaluation of designs. The code ASTEC is a joint research product of GRS (Germany) and IRSN (France) to simulate severe accidents (Van Dorsselaere et al, 2009;Coindreau et al, 2010;Dorsselaere et al, 2012;Chatelard et al, 2014). It is a relatively new and integrated code designed to predict all the behaviors during severe accidents in LWRs, such as any event in the beginning and any event with possible radiation related to a certain fission product.…”

Development and validation of the multi-physics DRACCAR code

“…Air oxidation of zirconium can actually lead to accelerated core degradation because of a kinetic transition called ''breakaway'' in the 600-1000°C temperature range, which modify the usual parabolic oxidation law into an accelerated regime. We used the MOZART model (Coindreau et al, 2010) in which the breakaway is taken into account via a critical mass gain parameter, based on the experimental data obtained at IRSN, in the framework of the MOZART program (Duriez et al, 2008). The ''breakaway'' option of the oxidation module is necessary to get code results closer to the experimental ones, but during the very moment of the ignition period at a given axial level, the very high experimental temperatures rates are not reached.…”