Study On The Thermal Decomposition Of Uranium Hydride And The Oxidation Characteristics Under Low Oxygen And Low Humidity Conditions

Because of its unique physical properties, UD3 has an important role in the national defense and nuclear facilities. UD3 was a material requiring great care because of its high reactivity with oxygen and decomposition. It reacts easily with air and the associated heat release is high.In this paper, its oxidation and decomposition has been systemically studied.The decomposition of the UD3 was studied systemically by the thermal desorption spectroscopy. In the TDS spectra, three distinct decomposition peaks were observed in the extreme high vacuum. When the temperature was between 20 ? and 153 ?, the first deuterium peak appeard. When the temperature got 155 ?, the second deuterium peak appeard. When the temperature got 167 ?, the third deuterium peak appeard. The fresh UD3 adsorbed the small amount of the H2O and O2 to generate a protective layer on its surface, which prevents the precipitation of the deuterium at temperatures below 150 ?. A P-V-T method was established to analyze the mass percentage of UD3 in the sample according to the characteristics of zinc and UD3. The PVT method improved the efficiency and accuracy of quantitative analysis.The crucible was kept at 550 ? for 0.5 h, Zinc and UD3 generated porous alloy which protects the uranium from deuterating.The influence of the hypoxic and low humidity storage for UD3 was researched systemically by the Quality curve and microcalorimetry method.The superficial passivation of the UD3 was research by the Quality curve, microcalorimetry method. At room temperature, the fresh UD3 adsorbed the small amount of the H2O and O2 to generate a protective layer on its surface which reduced the oxidative activity of the UD3. Analyzed by XRD and Raman measurements, it was found that the protective layer of the passivated UD3 is mainly UO2. In the environment of low humidity and hypoxic, UD3 quality increased rapidly to a certain extent, when the rate of the quality increasing was significantly reduced.The influence of superficial oxidation on the pyrophoric behaviour of UD3 was studied systemically by the microcalorimetry method. In the hypoxic and low humidity environment,UD3 generated a protective layer on its surface,which was damaged at about 160?170 ? in the air. With the extension of storage time,the characteristics of the protective layer was changed.145?150 ?. The protective layer was damaged at about 160?170 ? in the air.Its final products are UO2, U3O7, U4O9 and U3O8, the U3O8 is the least.