Solid state phase transformation kinetics in Zr-base alloys

A R Massih,Lars O Jernkvist

doi:10.1038/s41598-021-86308-w

A R Massih, Lars O Jernkvist

Open Access

https://doi.org/10.1038/s41598-021-86308-w

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Journal: Scientific Reports	Publication Date: Mar 29, 2021
Citations: 13	License type: open-access

Affiliation: Quantum Technologies (Sweden)

Abstract

We present a kinetic model for solid state phase transformation (alpha rightleftharpoons beta) of common zirconium alloys used as fuel cladding material in light water reactors. The model computes the relative amounts of beta or alpha phase fraction as a function of time or temperature in the alloys. The model accounts for the influence of excess oxygen (due to oxidation) and hydrogen concentration (due to hydrogen pickup) on phase transformation kinetics. Two variants of the model denoted by A and B are presented. Model A is suitable for simulation of laboratory experiments in which the heating/cooling rate is constant and is prescribed. Model B is more generic. We compare the results of our model computations, for both A and B variants, with accessible experimental data reported in the literature covering heating/cooling rates of up to 100 K/s. The results of our comparison are satisfactory, especially for model A. Our model B is intended for implementation in fuel rod behavior computer programs, applicable to a reactor accident situation, in which the Zr-based fuel cladding may go through alpha rightleftharpoons beta phase transformation.

Highlights

We present a kinetic model for solid state phase transformation ( α ⇋ β ) of common zirconium alloys used as fuel cladding material in light water reactors
To illustrate the phase transformation kinetics expected for reactor fuel cladding under a postulated loss-ofcoolant accident (LOCA) in a pressurized water reactor (PWR)[29], we apply model B to a cladding temperature history measured in a test within the QUENCH-LOCA experimental program at the Karlsruhe Institute of Technology, Germany
In this paper we have introduced a new model for the kinetics of α ⇋ β transformation in zirconium alloys used in the nuclear industry as fuel cladding material

Summary

Introduction

The α/β phase transformation temperatures were measured by dilatometric technique for Zircaloy-4L during heating at rates of 10 K/s and 100 K/s as a function hydrogen content (in the range 10–970 wppm) at β volume fractions 0.1, 0.5 and 0.9020.

Results

Conclusion