A Numerical Model for Prediction of Boundary Acid Concentration for Prevention of Polymerization at Macro Pu Concentrations

摘要

Under low aqueous acidity conditions, Pu(IV) hydrolysis and subsequent polymerization can cause severe problems during aqueous reprocessing of spent nuclear fuel. The solvent (30 vol% Tri-n-Butyl Phosphate in n-dodecane) used in PUREX process has almost negligible capacity for extraction of polymeric Pu(IV) thus it results in higher plutonium losses. In addition colloidal polymeric plutonium species can precipitate during acidification or heating causing accumulation of plutonium-a criticality risk. Thus knowledge of formation mechanism and proper identification of conditions leading to polymer formation is important for efficient design of reprocessing flowsheets.