The thermal conductivity of mixed fuel UxPu1-xO2: molecular dynamics simulations

Liu, Xiang-Yang¹  Cooper, Michael William Donald¹  Stanek, Christopher Richard¹  Andersson, Anders David Ragnar¹ 

[1] Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

关键词: MIXED OXIDE FUELS;    URANIUM DIOXIDE;    PLUTONIUM OXIDES;    THERMAL CONDUCTIVITY;    PWR TYPE REACTORS;    MOLECULAR DYNAMICS METHOD;    FBR TYPE REACTORS;    COMPUTERIZED SIMULATIONS;    MIXTURES;    TEMPERATURE DISTRIBUTION;    MICROSTRUCTURE;    PERFORMANCE;    TEMPERATURE RANGE 0400-1000 K;    TEMPERATURE RANGE 1000-4000 K;   

DOI  :  10.2172/1223768
RP-ID  :  LA-UR--15-28079
PID  :  OSTI ID: 1223768
Others  :  TRN: US1500439

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

Mixed oxides (MOX), in the context of nuclear fuels, are a mixture of the oxides of heavy actinide elements such as uranium, plutonium and thorium. The interest in the UO₂-PuO₂ system arises from the fact that these oxides are used both in fast breeder reactors (FBRs) as well as in pressurized water reactors (PWRs). The thermal conductivity of UO₂ fuel is an important material property that affects fuel performance since it is the key parameter determining the temperature distribution in the fuel, thus governing, e.g., dimensional changes due to thermal expansion, fission gas release rates, etc. For this reason it is important to understand the thermal conductivity of MOX fuel and how it differs from UO₂. Here, molecular dynamics (MD) simulations are carried out to determine quantitatively, the effect of mixing on the thermal conductivity of U_xPu_1-xO₂, as a function of PuO₂ concentrations, for a range of temperatures, 300 ??? 1500 K. The results will be used to develop enhanced continuum thermal conductivity models for MARMOT and BISON by INL. These models express the thermal conductivity as a function of microstructure state-variables, thus enabling thermal conductivity models with closer connection to the physical state of the fuel.