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Title: Electron microscopy study of Pd, Ag, and Cs in carbon areas in the locally corroded SiC layer in a neutron-irradiated TRISO fuel particle

Abstract

Mechanisms by which fission products migrate across the coating layers of tristructural isotropic (TRISO) coated particles, designed for next generation nuclear reactors, remain poorly understood despite numerous research activities. In this study, a crack across the buffer layer and the inner pyrolytic carbon (IPyC) layer was identified using X-ray tomography in a TRISO coated particle with ~30% Cs and ~85% Ag release. Detailed scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS) were performed on focused ion beam prepared lamellae from different locations close to and far away from the crack to study the distribution and composition of fission products across the IPyC and SiC layers in the areas examined. Pure carbon areas were found in areas in the SiC layer close to the crack tip. Precipitates present in these carbon areas consist mostly of Pd2Si, PdSi or Pd, with Ag and/or Cd frequently identified in these precipitates. Cs was found in nano-cracks and some precipitates in the carbon areas in the SiC layer. Areas in the SiC layer close to the crack tip with localized accumulation of Pd were corroded by Pd, forming pure carbon areas and palladium silicide. Such localized corroded areas provide pathways formore » Ag, Cd and Cs migration.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1469311
Report Number(s):
INL/JOU-15-36792-Rev000
Journal ID: ISSN 0955-2219; PII: S0955221918302991
Grant/Contract Number:  
AC05-00OR22725; AC07-05ID14517
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of the European Ceramic Society
Additional Journal Information:
Journal Volume: 38; Journal Issue: 12; Journal ID: ISSN 0955-2219
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS; tristructural isotropic; AGR; ART; inner pyrolytic carbon; scanning transmission electron microscopy; Fission product; Transport mechanism; Corrosion; Neutron irradiation; Electron microscopy; TRISO

Citation Formats

Wen, Haiming, van Rooyen, Isabella J., Hunn, John D., and Gerczak, Tyler J. Electron microscopy study of Pd, Ag, and Cs in carbon areas in the locally corroded SiC layer in a neutron-irradiated TRISO fuel particle. United States: N. p., 2018. Web. doi:10.1016/j.jeurceramsoc.2018.05.003.
Wen, Haiming, van Rooyen, Isabella J., Hunn, John D., & Gerczak, Tyler J. Electron microscopy study of Pd, Ag, and Cs in carbon areas in the locally corroded SiC layer in a neutron-irradiated TRISO fuel particle. United States. doi:10.1016/j.jeurceramsoc.2018.05.003.
Wen, Haiming, van Rooyen, Isabella J., Hunn, John D., and Gerczak, Tyler J. Mon . "Electron microscopy study of Pd, Ag, and Cs in carbon areas in the locally corroded SiC layer in a neutron-irradiated TRISO fuel particle". United States. doi:10.1016/j.jeurceramsoc.2018.05.003. https://www.osti.gov/servlets/purl/1469311.
@article{osti_1469311,
title = {Electron microscopy study of Pd, Ag, and Cs in carbon areas in the locally corroded SiC layer in a neutron-irradiated TRISO fuel particle},
author = {Wen, Haiming and van Rooyen, Isabella J. and Hunn, John D. and Gerczak, Tyler J.},
abstractNote = {Mechanisms by which fission products migrate across the coating layers of tristructural isotropic (TRISO) coated particles, designed for next generation nuclear reactors, remain poorly understood despite numerous research activities. In this study, a crack across the buffer layer and the inner pyrolytic carbon (IPyC) layer was identified using X-ray tomography in a TRISO coated particle with ~30% Cs and ~85% Ag release. Detailed scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS) were performed on focused ion beam prepared lamellae from different locations close to and far away from the crack to study the distribution and composition of fission products across the IPyC and SiC layers in the areas examined. Pure carbon areas were found in areas in the SiC layer close to the crack tip. Precipitates present in these carbon areas consist mostly of Pd2Si, PdSi or Pd, with Ag and/or Cd frequently identified in these precipitates. Cs was found in nano-cracks and some precipitates in the carbon areas in the SiC layer. Areas in the SiC layer close to the crack tip with localized accumulation of Pd were corroded by Pd, forming pure carbon areas and palladium silicide. Such localized corroded areas provide pathways for Ag, Cd and Cs migration.},
doi = {10.1016/j.jeurceramsoc.2018.05.003},
journal = {Journal of the European Ceramic Society},
issn = {0955-2219},
number = 12,
volume = 38,
place = {United States},
year = {2018},
month = {5}
}

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