Faire avancer la sûreté nucléaire

La Recherchev2


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



Email :

Mot de passe :

Journal of Nuclear Materials / Volume 405, Issue 3, 30 October 2010, Pages 207-215 

Type de document > *Article de revue

Mots clés >

Unité de recherche > IRSN/DPAM/SEMCA/LESAM

Auteurs > COINDREAU Olivia, DURIEZ Christian, EDERLI Stefano

Date de publication > 30/10/2010


Progress in the treatment of air oxidation of zirconium in severe accident (SA) codes are required for a reliable analysis of severe accidents involving air ingress. Air oxidation of zirconium can actually lead to accelerated core degradation and increased fission product release, especially for the highly-radiotoxic ruthenium. This paper presents a model to simulate air oxidation kinetics of Zircaloy-4 in the 600-1000 °C temperature range. It is based on available experimental data, including separate-effect experiments performed at IRSN and at Forschungszentrum Karlsruhe. The kinetic transition, named "breakaway", from a diffusion-controlled regime to an accelerated oxidation is taken into account in the modeling via a critical mass gain parameter. The progressive propagation of the locally initiated breakaway is modeled by a linear increase in oxidation rate with time. Finally, when breakaway propagation is completed, the oxidation rate stabilizes and the kinetics is modeled by a linear law. This new modeling is integrated in the severe accident code ASTEC, jointly developed by IRSN and GRS. Model predictions and experimental data from thermogravimetric results show good agreement for different air flow rates and for slow temperature transient conditions.

Texte complet