The Thermodynamics of Crystallization and Phase-Separation in Melt-Derived Nuclear Waste Forms

As outlined in the original proposal, this project combines the calorimetric expertise of Navrotsky, initially at UC Davis but now at ASU, with expertise at UT on structural studies especially by neutron diffraction, and with synthesis and characterization of glasses at PNNL. The goal is to understand the role of additives representative of fission products on the stability, structure, and crystallization of nuclear waste glasses . The goals and methodology remain the same with Navrotskys move to ASU where she is establishing a calorimetry lab modernized from that at UC Davis. Specifically, calorimetric studies by oxide melt solution calorimetry and differential scanning calorimetry ,of glasses doped with molybdenum and/or rare earths will be performed together with supporting analytical studies. Work on a series of base glasses (without dopants) has been completed and is being prepared for publication. Calorimetry on doped glasses will be emphasized at ASU in the remaining time of the grant and the results will be analyzed and prepared for publication.