Insight into Plutonium Intermediate Compounds Relevant to the Nuclear Fuel Cycle: Ionothermal Fluorination and Aging Study

The work presented herein pertains to: (1) the ionothermal synthesis of actinide fluorides utilizing 1-butyl-3-methylimidizaolium hexafluorophosphate, [Bmim][PF6], as the sole solvent and fluorinating agent. This method is unique in that most ionic liquid crystallization methods require a co-solvent to increase the solubility of the ionic liquid and the dissolution of the solute. This approach was used to fluorinate uranium(IV) and plutonium(IV) oxides, oxalates, and Pu(IV) nitrate to produce new powders and single crystals; and (2) the degradation pathway of plutonium oxalates when subjected to alpha-self-radiolysis under ambient laboratory conditions.

本文所阐述的研究工作涵盖以下两方面内容：(1) 以1-丁基-3-甲基咪唑六氟磷酸盐（1-butyl-3-methylimidazolium hexafluorophosphate，[Bmim][PF6]）作为唯一溶剂与氟化剂，开展锕系氟化物的离子热合成。相较于多数需借助助溶剂以提升离子液体溶解度、促进溶质溶解的离子液体结晶方法，该方法具有独特性。本研究利用该策略对四价铀、四价钚的氧化物、草酸盐以及四价钚硝酸盐进行氟化处理，成功制备出新型粉体与单晶；(2) 探究了实验室常规环境条件下，草酸钚发生α自辐解时的降解路径。