Gas-Phase Conversion of Uranium Mononitride in a Nitrating Atmosphere

摘要

Gas-phase conversion of UN to water-soluble compounds in NO_x-air, NO_x-H_2O (vapor)-air, or HNO_3 (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 UO_3 and hydrates of UO_2(NO_3)_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-H_2O (vapor)-air and HNO_3 (vapor)-air atmospheres, UN transforms into water-soluble compounds (nitrates, hydroxynitrates). The gas-phase conversion of UN in an NO_x-H_2O (vapor)-air atmosphere occurs less efficiently than that in an HNO_3 (vapor)-air atmosphere.