Abstract The purpose of this work is to determine how long UF4 in micro-particles can be detected after release in the environment, what the degradation products are and what are the parameters which mostly lead to degradation of UF4. For this, Raman spectra of UF4 μm-sized particles (typical diameters ∼5 μm) stored in various conditions (humid or dry air/argon, without or with UV light, 20 °C, 40 °C, 80 °C) were monitored by micro-Raman spectrometry over three months. The characteristic spectral signature of UF4 followed here is the very intense and broad fluorescence peak which covers the 700—1100 cm-1 region when a visible laser at 514 nm is used. This study shows that persistence of the UF4 signature in μm-sized particles released in the environment is strongly dependent on ambient conditions: typically a few days when submitted to both humid air or argon atmosphere and only intense UV light, a few weeks when exposed to a humid air or argon atmosphere in the dark, till at least several months and most probably several years, when kept in a dry atmosphere. Reaction of UF4 with water vapor ultimately leads to the formation uranyl hydroxide (schoepite) whereas exposure to both water vapor and UV light produces mainly uranyl peroxide (studtite).

中文翻译：

---

利用显微拉曼光谱研究环境条件下微米级四氟化铀 (UF4) 颗粒的化学变化

摘要 本工作的目的是确定微粒中的UF4在释放到环境中后多长时间可以被检测到，降解产物是什么以及主要导致UF4降解的参数是什么。为此，监测了储存在各种条件下（潮湿或干燥的空气/氩气，没有或有紫外线，20°C、40°C、80°C）的 UF4 μm 大小颗粒（典型直径约 5 μm）的拉曼光谱通过三个多月的显微拉曼光谱。当使用 514 nm 可见激光时，UF4 的特征光谱特征是非常强烈和宽广的荧光峰，覆盖 700-1100 cm-1 区域。这项研究表明，环境中释放的微米级颗粒中 UF4 特征的持久性在很大程度上取决于环境条件：通常在暴露于潮湿空气或氩气气氛和仅强紫外线下的情况下几天，在黑暗中暴露于潮湿空气或氩气气氛中时数周，直到至少几个月，最可能几年，当保存在干燥的气氛。UF4 与水蒸气的反应最终导致形成氢氧化铀酰（菱镁矿），而同时暴露于水蒸气和紫外线下主要产生过氧化铀酰（司铁矿）。