Gas-Phase Conversion of Uranium Mononitride in a Nitrating Atmosphere

Abstract

Gas-phase conversion of UN to water-soluble compounds in NO_x-air, NO_x-H₂O (vapor)-air, or HNO₃ (vapor)-air atmosphere (hereinafter, nitrating atmosphere) at temperatures from 298 to 673 K was studied. The use of the oxidizing atmosphere based on NO_x gases allows the conversion to be performed at a lower temperature. The process yields both UO₃ and hydrates of UO₂(NO₃)₂. The highest conversion of UN to water-soluble compounds, ∼80%, is reached at ∼565 K. In the course of gas-phase conversion in NO_x-H₂O (vapor)-air and HNO₃ (vapor)-air atmospheres, UN transforms into water-soluble compounds (nitrates, hydroxynitrates). The gas-phase conversion of UN in an NO_x-H₂O (vapor)-air atmosphere occurs less efficiently than that in an HNO₃ (vapor)-air atmosphere.