Continuum model for hydrogen pickup in Zirconium alloys of LWR fuel cladding

TL;DR

This study develops a continuum model to predict hydrogen pickup in Zirconium alloys used in nuclear fuel cladding, emphasizing the role of hydrogen diffusion through oxide layers, with promising qualitative agreement to experimental data.

Contribution

The paper introduces a simple continuum model with a single fitting parameter to accurately predict hydrogen pickup fractions in Zirconium alloys.

Findings

The model qualitatively matches experimental hydrogen pickup data.

Hydrogen diffusion through oxide layers is crucial in the pickup process.

The model highlights the importance of oxide layer properties in hydrogen absorption.

Abstract

A continuum model for calculating the time-dependent hydrogen pickup fractions in various Zirconium alloys under steam and pressured water oxidation has been developed in this study. Using only one fitting parameter, the effective hydrogen gas partial pressure at the oxide surface, a qualitative agreement is obtained between the predicted and previously measured hydrogen pickup fractions. The calculation results therefore demonstrate that H diffusion through the dense oxide layer plays an important role in the hydrogen pickup process. The limitations and possible improvement of the model are also discussed.