One of the original synthetic routes devised for the synthesis of U (III)N involved the entire reaction taking place in liquid ammonia. Several experimental reactions were conducted in an attempt to synthesize the UI3(NH3)x and U(NH2)3(NH3)x precursors of U(III) N. Each attempt involved cleaning of the uranium metal to remove the oxide coating of the metal reagent with 3 washes of concentrated nitric acid, each followed by a rinse with liquid ammonia. Success of this cleaning procedure was varied, with a majority of cleaned metal oxidizing rapidly once in contact with the liquid ammonia, despite the precautions taken to eliminate oxygen contamination in the reaction flasks. Due to the continual presence of oxide coating of the uranium metal, it was decided to alter the proposed synthetic route to utilize the synthesis of the UI-3 (THF)4 precursor, as described in Inorganic Chemistry. This involves the purification of THF through distillation, cleaning of the metal uranium, and slow reaction of U and I2. Equipment to perform this synthesis was not available for immediate use, but all necessary glassware was purchased.
It was discovered that the uranium metal turnings being used for the synthesis had a possibility of containing niobium as well. Waste solutions were analyzed by ICP-AES, and no niobium was identified. Other reaction waste solutions were also analyzed in order to determine the reactivity of uranium in the liquid ammonia solution. These analyses determined that only a minimal amount of uranium became dissolved, indicating that either there was little reactivity in the liquid ammonia or the reaction was only taking place on the surface of the metal. Neither of these possibilities is desirable, therefore the synthetic route involving THF was selected to avoid these outcomes.
Actinide elements; Mixed oxide fuels (Nuclear engineering); Nitrides; Nuclear chemistry; Nuclear fuels; Solid oxide fuel cells; Transmutation (Chemistry); Uranium compounds
Nuclear | Nuclear Engineering | Oil, Gas, and Energy | Physical Chemistry | Radiochemistry
Sullens, T. A.
Solution-Based Synthesis of Nitride Fuels.
Available at: https://digitalscholarship.unlv.edu/hrc_trp_fuels/76