Laboratory-scale quartz crucible melter tests for vitrifying a high-MoO3 raffinate waste simulant

Highlights: • Two ∼1 L melter tests were completed with a quartz crucible laboratory-scale melter. • The melter feed was a high-MoO₃ raffinate waste simulant from UNF. • The measured glass composition was very close to that of the target composition. -- Abstract: This paper details the results from two laboratory-scale (∼1 L) melter experiments where the processability was evaluated for vitrifying a simulated high-MoO₃ raffinate waste from reprocessing of used commercial nuclear fuel. The target glass (CSLNTM-C-2.5) contained roughly 18 mass% waste loading (2.5 mass% MoO₃). A homogeneous glass product was produced after process optimizations. Following the experiments, condensates present in the experimental apparatus were analyzed and found to be primarily composed of SiO₂, Al₂O₃, Zr-O, rare earth, molybdate, and nitrate phases. The composition of the glassy product resulting from the second melter experiment was very similar to that of the target composition with variations noted for Al, Mo, and Zr.