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Uranium dioxide or uranium(IV) oxide (UO 2), also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used as MOX fuel.
According to the International Nuclear Safety Center [22] the thermal conductivity of uranium dioxide can be predicted under different conditions by a series of equations. The bulk density of the fuel can be related to the thermal conductivity. Where ρ is the bulk density of the fuel and ρ td is the theoretical density of the uranium dioxide.
The fission products can modify the thermal properties of the uranium dioxide; ... If the irradiation period has been short then the plutonium is weapons-grade (more ...
This page describes how uranium dioxide nuclear fuel behaves during both normal nuclear reactor operation and under reactor accident conditions, such as overheating. Work in this area is often very expensive to conduct, and so has often been performed on a collaborative basis between groups of countries, usually under the aegis of the Organisation for Economic Co-operation and Development's ...
Uranium dioxide (UO 2) can be oxidised to an oxygen rich hyperstoichiometric oxide (UO 2+x) which can be further oxidised to U 4 O 9, U 3 O 7, U 3 O 8 and UO 3.2H 2 O. Because used fuel contains alpha emitters (plutonium and the minor actinides), the effect of adding an alpha emitter (238 Pu) to uranium dioxide on the leaching rate of the oxide ...
Uranium dioxide is the form in which uranium is most commonly used as a nuclear reactor fuel. [3] At ambient temperatures, UO 2 will gradually convert to U 3 O 8. Because of their stability, uranium oxides are generally considered the preferred chemical form for storage or disposal. [3]
The uranium to zirconium ratio in different parts of the solid differs a lot, in the brown lava a uranium-rich phase with a U:Zr ratio of 19:3 to about 19:5 is found. The uranium-poor phase in the brown lava has a U:Zr ratio of about 1:10. [37] It is possible from the examination of the Zr/U phases to determine the thermal history of the mixture.
Post Irradiation Examination (PIE) is the study of used nuclear materials such as nuclear fuel. It has several purposes. It has several purposes. It is known that by examination of used fuel that the failure modes which occur during normal use (and the manner in which the fuel will behave during an accident) can be studied.