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Title: STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment

Authors:
; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1341161
Grant/Contract Number:
AC07-05ID14517
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 475; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 15:25:34; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Leng, B., van Rooyen, I. J., Wu, Y. Q., Szlufarska, I., and Sridharan, K. STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment. Netherlands: N. p., 2016. Web. doi:10.1016/j.jnucmat.2016.03.008.
Leng, B., van Rooyen, I. J., Wu, Y. Q., Szlufarska, I., & Sridharan, K. STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment. Netherlands. doi:10.1016/j.jnucmat.2016.03.008.
Leng, B., van Rooyen, I. J., Wu, Y. Q., Szlufarska, I., and Sridharan, K. 2016. "STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment". Netherlands. doi:10.1016/j.jnucmat.2016.03.008.
@article{osti_1341161,
title = {STEM-EDS analysis of fission products in neutron-irradiated TRISO fuel particles from AGR-1 experiment},
author = {Leng, B. and van Rooyen, I. J. and Wu, Y. Q. and Szlufarska, I. and Sridharan, K.},
abstractNote = {},
doi = {10.1016/j.jnucmat.2016.03.008},
journal = {Journal of Nuclear Materials},
number = C,
volume = 475,
place = {Netherlands},
year = 2016,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.jnucmat.2016.03.008

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  • Here, detailed electron microscopy studies were performed to investigate the distribution and composition of fission products in the SiC layer of a tristructural isotropic coated particle exhibiting localized corrosion. Previous studies on this particle indicated that pure carbon areas in the SiC layer, resulting from localized corrosion of SiC by Pd, provide pathways for Ag, Cd and Cs migration. This study reveals the presence of Ag- and/or Cd-containing precipitates in un-corroded SiC areas. Ag/Cd may exist by themselves or coexist with Pd. Ag/Cd mainly transport along SiC grain boundaries. An Ag-Pd-Cd precipitate was identified at a stacking fault inside amore » SiC grain, suggesting that intragranular transport of Ag/Cd is possible. Ce is present with Pd or Pd-U in some precipitates >50 nm. U and Ce frequently coexist with each other, whereas Ag/Cd usually does not coexist with U or Ce. No Cs was detected in any precipitates in the areas examined.« less
  • Post-irradiation examination of coated particle fuel from the AGR-1 experiment is in progress at Idaho National Laboratory and Oak Ridge National Laboratory. In this paper a brief summary of results from characterization of microstructures in the coating layers of selected irradiated fuel particles with burnup of 11.3% and 19.3% FIMA will be given. The main objectives of the characterization were to study irradiation effects, fuel kernel porosity, layer debonding, layer degradation or corrosion, fission-product precipitation, grain sizes, and transport of fission products from the kernels across the TRISO layers. Characterization techniques such as scanning electron microscopy, transmission electron microscopy, energymore » dispersive spectroscopy, and wavelength dispersive spectroscopy were used. A new approach to microscopic quantification of fission-product precipitates is also briefly demonstrated. Microstructural characterization focused on fission-product precipitates in the SiC-IPyC interface, the SiC layer and the fuel-buffer interlayer. The results provide significant new insights into mechanisms of fission-product transport. Although Pd-rich precipitates were identified at the SiC-IPyC interlayer, no significant SiC-layer thinning was observed for the particles investigated. Characterization of these precipitates highlighted the difficulty of measuring low concentrations of Ag in precipitates with significantly higher concentrations of Pd and U. Different approaches to resolving this problem are discussed. An initial hypothesis is provided to explain fission-product precipitate compositions and locations. No SiC phase transformations were observed and no debonding of the SiC-IPyC interlayer as a result of irradiation was observed for the samples investigated. Lessons learned from the post-irradiation examination are described and future actions are recommended.« less
  • Tristructural isotropic (TRISO) coated particle fuel is a promising fuel form for advanced reactor concepts such as high temperature gas-cooled reactors (HTGR) and is being developed domestically under the US Department of Energy’s Nuclear Reactor Technologies Initiative in support of Advanced Reactor Technologies. The fuel development and qualification plan includes a series of fuel irradiations to demonstrate fuel performance from the laboratory to commercial scale. The first irradiation campaign, AGR-1, included four separate TRISO fuel variants composed of multiple, laboratory-scale coater batches. The second irradiation campaign, AGR-2, included TRISO fuel particles fabricated by BWX Technologies with a larger coater representativemore » of an industrial-scale system. The SiC layers of as-fabricated particles from the AGR-1 and AGR-2 irradiation campaigns have been investigated by electron backscatter diffraction (EBSD) to provide key information about the microstructural features relevant to fuel performance. The results of a comprehensive study of multiple particles from all constituent batches are reported. The observations indicate that there were microstructural differences between variants and among constituent batches in a single variant. Finally, insights on the influence of microstructure on the effective diffusivity of key fission products in the SiC layer are also discussed.« less