Chemical Decomposition of High-Level Nuclear Waste Storage/Disposal Glasses Under Irradiation

The objective of this project is to employ the technique of electron spin resonance (ESR), in conjunction with other experimental methods, to study radiation-induced decomposition of vitreous compositions proposed for immobilization/disposal of high-level nuclear wastes (HLW) or excess weapons plutonium. ESR is capable of identifying, even at the parts-per-million level, displaced atoms, ruptured bonds, and free radicals created by radiation in such glassy forms. For example, one of the scientific goals is to search for ESR-detectable superoxide (O2 -) and ozonide (O3 -) ions, which could be precursors of radiation-induced oxygen gas bubbles reported by other investigators via the disproportionation reaction, 2O2 - : O2 2- + O2. The fundamental understandings obtained in this study will enable reliable predictions of the long-term effects of a and B decays of the immobilized radionuclides on the chemical integrity of HLW glasses