Thermal Conductivity of beginning-of-life uranium-plutonium mixed oxide fuel for fast reactor

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Thermal conductivity of uranium-plutonium mixed oxide fuel for fast reactor at beginning-of-life was correlated based on the recent results in order to apply to the fuel design and the fuel performance analysis. A number of experimental results of unirradiated fuel speimens were corrected from open literatures and PNC internal reports and examined for the database. Thermal conductivity of acutual fuel with porosity (), that of fully dense fuel ( 100%TD) and porosity correction factor (F) had theoretically the following correlation : = F 100%TD. The following correlation was developed for fully dense fuel by the results of high density fuel pellets which the effect of porosity was relatively small. The data base ranged from 17 to 30% for plutonium content in heavy metal atoms, from 1.90 to 2.00 for oxygen to metal ratio, from 90 to 98% of theoretical density and from 400 to 2090 degree C for temperature. = (1/(-0.03237+0.8606+2.48310T))+75.2710T where 100%TD: Thermal Conductivity (W/mK) T: Temperature (K) O/Z: Oxygen-to-metal ratio (-) In this work two porosity correction factors were needed for high density fuel and low density fuel (around the current Monju specification). For high density fuel (as-fabricated fuel density : 90%TD) F = 1-2.95P(P:Porosity volume Fraction (-)) For low density fuel (as-fabricated fuel density: around 85%TD) F = 1-1.4P (P: Porosity volume Fraction (-)) The universal porosity correction factor was not determined in this work. In the next step, theoretical and analytical considerations should be taken into account.