Thermal expansion and steam oxidation of uranium mononitride analysed via in situ neutron diffraction

Publication Name

Journal of Nuclear Materials


In situ neutron powder diffraction experiments are applied to physical, kinetic, and microstructural characterization of uranium mononitride as a promising light water reactor fuel material. The temperature-variable coefficient of thermal expansion and isotropic Debye Waller factors are obtained by sequential Rietveld refinement over 499–1873 K. Oxidation of a UN pellet (95.2% density) under flow of 11 mg/min D2O is observed to initiate above 623 K and the rate increases by a factor of approximately 10 from 673 to 773 K, with activation energy 50.6 ± 1.3 kJ/mol; uranium oxide is the only solid corrosion product.

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Funding Number


Funding Sponsor

Australian Nuclear Science and Technology Organisation



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