Observation of crack microstructure in oxides and its correlation to oxidation and hydrogen-uptake by 3D FIB Tomography – case of Zr-ZrO2 in reactor

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • Paul Scherrer Institut

Abstract

Zirconium based alloys are used as fuel claddings in Light Water Reactors due to their good resistance to degradation and low neutron absorption cross section. However, life limiting processes occur during the service of the cladding such as oxidation and hydrogen-uptake. During the oxidation of the material, hydrogen enters the metal and it precipitates as brittle hydrides. In this study the 3D microstructure of a high burn-up and a low-burnup LK3/L Zircaloy-2 cladding is characterized and compared using FIB Tomography. 3D reconstruction of the oxides of the claddings shows that the crack volume fraction increases with the number of cycles in the reactor, reducing its protectiveness against further corrosion and H-uptake. The visualization of the metal-oxide interface revealed that the oxidation of the hydrides in the metal could induce crack formation in the oxide and therefore it could be one of the causes of the increasing oxidation and H-uptake in this material.

Details

Original languageEnglish
Pages (from-to)14-21
JournalMaterials at High Temperatures
Volume35
Early online date26 Oct 2017
Publication statusPublished - 2018

Keywords

  • 3D reconstruction, FIB Tomography, Zircaloy-2, H-uptake, oxidation, crack formation