Abstracts and Available Papers Presented at the
2002 International RERTR Meeting

MODELING OF HIGH-DENSITY U-Mo DISPERSION FUEL PLATE PERFORMANCE

S. L. Hayes^a, G. L. Hofman^b, M. K. Meyer^a, J. Rest^b and J. L. Snelgrove^b

^aArgonne National Laboratory
P. O. Box 2528
Idaho Falls, ID 83403-2528 USA

^bArgonne National Laboratory
9700 South Cass Avenue
Chicago, IL 60439-4803 USA

ABSTRACT

Results from postirradiation examinations (PIE) of highly loaded U-Mo/Al dispersion fuel plates over the past several years have shown that the interaction between the metallic fuel particles and the matrix aluminum can be extensive, reducing the volume of the high-conductivity matrix phase and producing a significant volume of low-conductivity reaction-product phase.  This phenomenon results in a significant decrease in fuel meat thermal conductivity during irradiation.  PIE has further shown that the fuel-matrix interaction rate is a sensitive function of irradiation temperature.  The interplay between fuel temperature and fuel-matrix interaction makes the development of a simple empirical correlation between the two difficult.  For this reason a comprehensive thermal model has been developed to calculate temperatures throughout the fuel plate over its lifetime, taking into account the changing volume fractions of fuel, matrix and reaction-product phases within the fuel meat owing to fuel-matrix interaction; this thermal model has been incorporated into the dispersion fuel performance code designated PLATE.  Other phenomena important to fuel thermal performance that are also treated in PLATE include:  gas generation and swelling in the fuel and reaction-product phases, incorporation of matrix aluminum into solid solution with the unreacted metallic fuel particles, matrix extrusion resulting from fuel swelling, and cladding corrosion.  The phenomena modeled also make possible a prediction of fuel plate swelling.  This paper presents a description of the models and empirical correlations employed within PLATE as well as validation of code predictions against fuel performance data for U-Mo experimental fuel plates from the RERTR-3 irradiation test.

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