Electron Microscopy Study of Pd, Ag, and Cs in Carbon Areas in the Locally Corroded SiC Layer in a Neutron-Irradiated TRISO Fuel Particle


A detailed electron microscopy study was performed on focused ion beam-prepared lamellae from different locations relative to a crack across the inner pyrolytic carbon layer of a neutron-irradiated tristructural isotropic-coated particle. The distribution and composition of fission products across the inner pyrolytic carbon and silicon carbide (SiC) layers were studied. Previously, this crack was identified in the particle that released significant inventory fractions of cesium and silver during irradiation and displayed localized palladium pileup with SiC degradation. In this study, carbon areas were found in the SiC layer close to the crack tip and they had precipitates that consisted mostly of palladium silicides or palladium, with silver and/or cadmium frequently identified. Results confirmed that areas in the SiC layer close to the crack tip with localized accumulation of palladium were corroded by palladium, forming pure carbon areas and palladium silicide that provided pathways for silver, cadmium and cesium migration.


Materials Science and Engineering

Research Center/Lab(s)

Intelligent Systems Center

Keywords and Phrases

Corrosion; Fission Product; Neutron Irradiation; Transport Mechanism; TRISO Particle

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2018 Elsevier Ltd, All rights reserved.

Publication Date

01 Sep 2018