Cladding oxidation during air ingress. Part II: Synthesis of modelling results. (July 2016)

• Record Type: Journal Article
• Authors: Beuzet, E.; Haurais, F.; Bals, C.; Coindreau, O.; Fernandez-Moguel, L.; Vasiliev, A.; Park, S.
• Is Part Of: Annals of nuclear energy. Volume 93(2016:Jul.)
• Page Start: 18
• Page End: 27
• Publication Date: 2016-07
• Subjects: Severe accident code -- Cladding oxidation -- Air -- Nitriding -- QUENCH -- PARAMETER; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2015.12.031
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: A state-of-the-art for air oxidation modelling in the frame of severe accident is done. Air oxidation models from main severe accident codes are detailed. Simulations from main severe accident codes are compared against experimental results. Perspectives in terms of need for further model development and experiments are given. Abstract: Air ingress is a potential risk in some low probable situations of severe accidents in a nuclear power plant. Air is a highly oxidizing atmosphere that can lead to an enhanced Zr-based cladding oxidation and core degradation affecting the release of fission products. This is particularly true speaking about ruthenium release, due to its high radiotoxicity and its ability to form highly volatile oxides in a significant manner in presence of air. The oxygen affinity is decreasing from the Zircaloy cladding, fuel and ruthenium inclusions. It is consequently of great need to understand the phenomena governing cladding oxidation by air as a prerequisite for the source term issues in such scenarios. In the past years, many works have been done on cladding oxidation by air under severe accident conditions. This paper with in addition the paper "Cladding oxidation during air ingress – Part I: Synthesis of experimental results" of this journal issue aim at assessing the state of the art on this phenomenon. In this paper, the modelling of air ingress phenomena in the main severe accident codes (ASTEC, ATHLET-CD, MAAP, MELCOR, RELAP/SCDAPSIM, SOCRAT) is described in details, as well as the validation against the integral experiments QUENCH-10, QUENCH-16 and PARAMETER-SF4. A full review of cladding oxidation by air is thus established.