Radiation induced degradation of chlorinated polymers, such as poly(vinyl chloride) (PVC), used historically in packaging of PuO2, has led to chloride-contaminated PuO2, which constitutes a significant proportion of the Pu inventory. Reuse of the chloride contaminated plutonium requires treatment of the PuO2 to reduce Cl- contamination to acceptable levels for fuel manufacture; whereas storage requires stabilisation coupled with a predictive understanding of the evolution of Cl–contaminated PuO2 over time.