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Abstract

The kinetics of formation of uranium-neptunium mononitride by carbothermic reduction of uranium and neptunium oxides under flowing nitrogen has been investigated, using thermogravimetric techniques in the temperature range 1670-1870 K. The starting blends were prepared from powder material and contained carbon in excess of the amount required to obtain the stoichiometric composition. The reactions investigated were carbothermic synthesis of a low-carbon carbonitride containing free carbon, and decarburisation of the carbonitride under nitrogen-8% hydrogen gas mixture. The carbothermic synthesis follows a first order rate equation and the value of the activation energy lies in the range 344 to 385 kJ/mol. No clear dependence of the activation energy on the neptunium or carbon content of the starting blends was found. The removal of carbon impurity follows a phase boundary type rate equation with an activation energy of about 210 kJ/mol.

Additional information

Authors: ARAI Y, Japan Atomic Energy Research Institute, Department of Fuels and Materials Research, Oarai-machi, Ibaraki-ken (JP);SARI C, JRC Karlsruhe (DE);SPIRLET J C, JRC Karlsruhe (DE)
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 185 (1991) 159-166
Record Number: 199210093 / Last updated on: 1994-12-02
Category: PUBLICATION
Original language: en
Available languages: en