1. The effect of oxygen concentration on the speciation of laser ablated uranium.
- Author
-
Burton, Mark A., Auner, Alex W., Crowhurst, Jonathan C., Boone, Peter S., Finney, Lauren A., Weisz, David G., Koroglu, Batikan, Jovanovic, Igor, Radousky, Harry B., and Knight, Kim B.
- Subjects
URANIUM ,CHEMICAL processes ,ENERGY dispersive X-ray spectroscopy ,URANIUM oxides ,NUCLEAR explosions ,INFRARED absorption - Abstract
In order to model the fate and transport of particles following a nuclear explosion, there must first be an understanding of individual physical and chemical processes that affect particle formation. One interaction pertinent to fireball chemistry and resultant debris formation is that between uranium and oxygen. In this study, we use laser ablation of uranium metal in different concentrations of oxygen gas, either
16 O2 or18 O2 , to determine the influence of oxygen on rapidly cooling uranium. Analysis of recovered particulates using infrared absorption and Raman spectroscopies indicate that the micrometer-sized particulates are predominantly amorphous UOx (am-UOx , where 3 ≤ x ≤ 4) and UO2 after ablation in 1 atm of pure O2 and a 1% O2 /Ar mixture, respectively. Energy dispersive X-ray spectroscopy (EDS) of particulates formed in pure O2 suggest an O/U ratio of ~ 3.7, consistent with the vibrational spectroscopy analysis. Both am-UOx and UO2 particulates convert to α-U3 O8 when heated. Lastly, experiments performed in18 O2 environments show the formation of18 O-substituted uranium oxides; vibrational frequencies for am-U18 Ox are reported for the first time. When compared to literature, this work shows that cooling timescales can affect the structural composition of uranium oxides (i.e., crystalline vs. amorphous). This indicator can be used in current models of nuclear explosions to improve our predicative capabilities of chemical speciation. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF