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Title: INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL

Abstract

Internal pressurization and diametrical loading techniques were developed to measure the fracture strength of the chemical vapor deposition (CVD) silicon carbide (SiC) coatings in nuclear fuel particles. Miniature tubular and hemispherical shell specimens were used for both test methods. In the internal pressurization test an expansion load was applied to the inner surface of a specimen by use of a compressively loaded elastomeric insert (polyurethane). In the crush test a diametrical compressive load was applied to the outer surface(s) of a specimen. The test results revealed that the fracture strengths from four test methods obeyed Weibull's two-parameter distribution, and the measured values of the Weibull modulus were consistent for different test methods. The fracture strengths measured by crush test techniques were larger than those by internal pressurization tests. This is because the internal pressurization produces uniform stress distribution while the diametrical loading technique produces severely localized stress distribution. The test method dependence of fracture strength was explained by the size effect predicted by effective surface.

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
930729
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Symposium on Ceramics on Nuclear and Alternative Energy Applications, Cocoa Beach, FL, USA, 20060122, 20060127
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 36 MATERIALS SCIENCE; CERAMICS; CHEMICAL VAPOR DEPOSITION; COATINGS; CONFIGURATION; DISTRIBUTION; FRACTURE PROPERTIES; NUCLEAR FUELS; PRESSURIZATION; SILICON CARBIDES

Citation Formats

Byun, Thak Sang, Hong, Seong Gu, Katoh, Yutai, and Snead, Lance Lewis. INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL. United States: N. p., 2006. Web.
Byun, Thak Sang, Hong, Seong Gu, Katoh, Yutai, & Snead, Lance Lewis. INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL. United States.
Byun, Thak Sang, Hong, Seong Gu, Katoh, Yutai, and Snead, Lance Lewis. Sun . "INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL". United States. doi:.
@article{osti_930729,
title = {INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL},
author = {Byun, Thak Sang and Hong, Seong Gu and Katoh, Yutai and Snead, Lance Lewis},
abstractNote = {Internal pressurization and diametrical loading techniques were developed to measure the fracture strength of the chemical vapor deposition (CVD) silicon carbide (SiC) coatings in nuclear fuel particles. Miniature tubular and hemispherical shell specimens were used for both test methods. In the internal pressurization test an expansion load was applied to the inner surface of a specimen by use of a compressively loaded elastomeric insert (polyurethane). In the crush test a diametrical compressive load was applied to the outer surface(s) of a specimen. The test results revealed that the fracture strengths from four test methods obeyed Weibull's two-parameter distribution, and the measured values of the Weibull modulus were consistent for different test methods. The fracture strengths measured by crush test techniques were larger than those by internal pressurization tests. This is because the internal pressurization produces uniform stress distribution while the diametrical loading technique produces severely localized stress distribution. The test method dependence of fracture strength was explained by the size effect predicted by effective surface.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

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  • No abstract prepared.
  • A program to develop new methods to measure the fracture strength of the chemical vapor deposition (CVD) SiC coatings in nuclear fuel particles has been carried out. Internal pressurization and crush test techniques were developed and applied to prototype-sized tubular and hemispherical shell specimens. The fracture strength measured from each test method applying the Weibull two-parameter distribution, and Weibull parameters measured. It was shown that data generated with each test technique were independent of the test technique applied. This implies the developed test methods are reliable and provide reasonable strength data. For the same material, fracture strength varied with themore » specimen geometry and loading configuration. This size and loading configuration effects on the fracture strength are explained with the concept of effective surface.« less
  • The mechanical properties of the silicon carbide (SiC) layer of the TRi-ISOtropic (TRISO) coated particle (CP) for high temperature gas reactors (HTGR) are performance parameters that have not yet been standardized by the international HTR community. Presented in this paper are the results of characterizing coated particles to reveal the effect of annealing temperature (1000 to 2100°C) on the strength and grain size of unirradiated coated particles. This work was further expanded to include possible relationships between the grain size and strength values. The comparative results of two strength measurement techniques and grain size measured by the Lineal intercept methodmore » are included. Preliminary grain boundary characterization results determined by electron backscatter diffraction (EBSD) are included. These results are also important for future fission product transport studies, as grain boundary diffusion is identified as a possible mechanism by which 110mAg, one of the fission activation products, might be released through intact SiC layers. Temperature is a parameter known to influence the grain size of SiC and therefore it is important to investigate the effect of high temperature annealing on the SiC grain size. Recommendations and future work will also be briefly discussed.« less
  • Fracture stress data for the chemical vapor deposition (CVD) SiC coatings of tri-isotropic (TRISO) carbon/silicon carbide coated fuel particles were obtained using a newly developed testing and evaluation method, and their relationship with microstructure investigated. A crush testing technique using a blanket foil at load-transferring contact has been developed for hemispherical shell SiC specimens based on finite element (FE) analysis results. Mean fracture stress varied with test material in the range of 330 650 MPa, and was connected to the combined characteristics of inner surface roughness and porosity.