Three dimensional calculations of the effective Kapitza resistance of UO2 grain boundaries containing intergranular bubbles

Modeling of thermo-mechanical and irradiation behavior of mixed oxide fuel for sodium fast reactors

Fuel-to-cladding gap evolution and its impact on thermal performance of high burnup fast reactor type uranium–plutonium oxide fuel pins

Solid solution effects on thermal conductivity within the MgO–Al2O3–Ga2O3 system were studied. Samples with systematically varied additions of MgGa2O4–MgAl2O4 were prepared and the laser flash technique was used to determine thermal diffusivity at temperatures between 200°C and 1300°C. Heat capacity as a function of temperature from room temperature to 800°C was also determined using differential scanning calorimetry (DSC). Solid solution in the MgAl2O4–MgGa2O4 system decreases the thermal conductivity up to 1000°C. At 200°C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. At 1000°C, the thermal conductivity decreased 13% with a 5 mol% addition. Steady-state calculations showed a 12.5% decrease in heat flux with 5 mol% MgGa2O4 considered across a 12 inch thickness.

Solid Solution Effects on the Thermal Properties in the MgAl2O4–MgGa2O4 System

The behavior of nuclear fuel during irradiation is largely dependent on its thermophysical properties and their change with temperature and burnup Experimental data on out-of-pile properties such as melting point, density, thermal conductivity, and thermal expansion are required for fuel design, performance modeling, and safety analysis The variables that influence the out-of-pile properties are fuel composition, temperature, porosity, microstructure, and burnup Among the above-mentioned properties, thermal conductivity of nuclear fuel is the most important property which influences almost all the processes such as swelling, grain growth, and fission gas release, and limits the linear power The changes in thermal conductivity occur during irradiation by the formation of fission gas bubbles, porosities, build-up of fission products, and by the change of fuel stoichiometry Melting point plays a crucial role in determining the power to melt the fuel and decides the operating linear heat rating The coefficient of thermal expansion (CTE) is needed to calculate stresses occurring in the fuel and cladding on change in temperature In safety analysis, the values of thermal expansion data are required in determining the gap conductance and the stored energy

Kazuyuki Abe

Papers

A method for determining an effective porosity correction factor for thermal conductivity in fast reactor uranium–plutonium oxide fuel pellets