Corrosion of Zirconium Alloys Used for Nuclear Fuel Cladding

Abstract

During operation, nuclear fuel rods are immersed in the primary water, causing waterside corrosion and consequent hydrogen ingress. In this review, the mechanisms of corrosion and hydrogen pickup and the role of alloy selection in minimizing both phenomena are considered on the basis of two principal characteristics: the pretransition kinetics and the loss of oxide protectiveness at transition. In zirconium alloys, very small changes in composition or microstructure can cause significant corrosion differences so that corrosion performance is strongly alloy dependent. The alloys show different, but reproducible, subparabolic pretransition kinetics and transition thicknesses. A mechanism for oxide growth and breakup based on a detailed study of the oxide structure can explain these results. Through the use of the recently developed coupled current charge compensation model of corrosion kinetics and hydrogen pickup, the subparabolic kinetics and the hydrogen fraction can be rationalized: Hydrogen pickup increases when electron transport decreases, requiring hydrogen ingress to close the reaction.

Oxygen self-diffusion mechanisms in monoclinic ZrO2 revealed and quantified by density functional theory, random walk analysis, and kinetic Monte Carlo calculations

“…Oxygen self-diffusion in zirconium oxide has long been a topic of interest [1][2][3][4] in studying the oxidation kinetics of zirconium alloys, which are used as cladding of nuclear fuel in light water cooled nuclear reactors [5]. Zirconium oxide is also widely used in heterogeneous catalysis [6,7], and more recently it was examined for high-k dielectrics in metal-oxide-semiconductor field-effect transistor (MOSFET) devices [8,9] as well as resistive switching devices [10,11].…”

Analisis Korosi Paduan ZIRLO-Mo Dalam Media NaCl Menggunakan Metode Polarisasi

“…Usaha untuk meningkatkan sifat mekaniknya perlu dilakukan modifikasi komposisi atau pengembangan dengan cara menambahkan unsur Mo ke dalam bahan tersebut [10].…”

“…Sementara itu, pada sampel zircaloy-2 dan zircaloy-4 dalam kondisi annealed mempunya struktur lebih homogen dan bebas tegangan sisa sehingga ketahanan korosinya lebih baik. Hal ini didukung oleh hasil penelitian lainnya yang menggunakan autoclave pada temperatur dan tekanan tinggi menunjukkan bahwa penambahan unsur Mo hingga 0,5% dapat meningkatkan laju korosi [10].…”

Modelling of Nuclear Fuel Cladding Tubes Corrosion

“…Zirconium-based alloys has been used as the nuclear fuel cladding since 1950s [6]. There were originally two main groups of Zr-based alloys developed: During the evolution of the nuclear fuel, fuel vendors and research organizations developed dozens of concepts of fuel cladding alloys.…”

“…The model was developed by experimental data fitting and is more precise for higher values of oxide thickness than model developed by Garzarolli et al [8]. Oxide layer growth during the first phase can be calculated by the following expression [6] …”