Assessment of a mechanistic model in U-Pu-Zr metallic alloy fuel fission-gas behavior simulations

Conference · Sun Jul 01 00:00:00 EDT 2012

OSTI ID:22107894

Yun, D.; Rest, J.; Yacout, A. M. ^[1]

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1. Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

A mechanistic kinetic rate theory model originally developed for the prediction of fission gas behavior in oxide nuclear fuels under steady-state and transient conditions has been assessed to look at its applicability to model fission gas behavior in U-Pu-Zr metallic alloy fuel. In order to capture and validate the underlying physics for irradiated U-Pu-Zr fuels, the mechanistic model was applied to the simulation of fission gas release, fission gas and fission product induced swelling, and the evolution of the gas bubble size distribution in three different fuel zones: the outer {alpha}-U, the intermediate, and the inner {gamma}-U zones. Due to its special microstructural features, the {alpha}-U zone in U-Pu-Zr fuels is believed to contribute the largest fraction of fission gas release among the different fuel zones. It is shown that with the use of small effective grain sizes, the mechanistic model can predict fission gas release that is consistent with (though slightly lower than) experimentally measured data. These simulation results are comparable to the experimentally measured fission gas release since the mechanism of fission gas transport through the densely distributed laminar porosity in the {alpha}-U zone is analogous to the mechanism of fission gas transport through the interconnected gas bubble porosity utilized in the mechanistic model. Detailed gas bubble size distributions predicted with the mechanistic model in both the intermediate zone and the high temperature {gamma}-U zone of U-Pu-Zr fuel are also compared to experimental measurements from available SEM micrographs. These comparisons show good agreements between the simulation results and experimental measurements, and therefore provide crucial guidelines for the selection of key physical parameters required for modeling these two zones. In addition, the results of parametric studies for several key parameters are presented for both the intermediate zone and the {gamma}-U zone simulations. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 22107894
• Resource Relation: Conference: ICAPP '12: 2012 International Congress on Advances in Nuclear Power Plants, Chicago, IL (United States), 24-28 Jun 2012; Other Information: Country of input: France; refs.; Related Information: In: Proceedings of the 2012 International Congress on Advances in Nuclear Power Plants - ICAPP '12| 2799 p.
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
22 GENERAL STUDIES OF NUCLEAR REACTORS
BUBBLES
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
FISSION PRODUCT RELEASE
FISSION PRODUCTS
GRAIN SIZE
NUCLEAR FUELS
NUCLEAR MODELS
OXIDES
PARAMETRIC ANALYSIS
PLUTONIUM ALLOYS
POROSITY
SCANNING ELECTRON MICROSCOPY
STEADY-STATE CONDITIONS
SWELLING
TEMPERATURE RANGE 0400-1000 K
URANIUM ALLOYS
ZIRCONIUM ALLOYS