Radiolytic degradation of n-dodecane: Insights from time resolved pulsed electron radiolysis using aromatic scavengers

This study uses time-resolved picosecond pulsed electron radiolysis and transient absorbance spectroscopy to investigate early radiolytic processes in n -dodecane, a prototypical organic solvent for reprocessing used nuclear fuel (UNF). The primary radical cation, solvated electron, and excited states in neat n -dodecane are formed and consumed on timescales that are difficult to observe directly. Aromatic solutes, biphenyl and benzophenone, were utilized as scavengers to convert these short-lived species into longer-lived, optically detectable transient products to serve as indirect probes of the fraction of the initial n -dodecane radiolytic products that can be intercepted before undergoing ultrafast decay or competing reactions. The transient absorbance spectra of these scavengers and their radiolytic products were analyzed. Results indicate that while biphenyl and benzophenone effectively capture several radiolytic species, they do not fully scavenge all n -dodecane excited states, suggesting potential inefficiencies or additional side reactions. This study provides insight into the formation and accessibility of radiation-induced excited states and charge carriers in n -dodecane, which play a key role in the degradation of solvent extraction systems used in UNF reprocessing.