New Fission-Product Waste Forms: Development and Characterization

Technical Report · Fri Jul 30 04:00:00 EDT 2010

DOI:https://doi.org/10.2172/984328· OSTI ID:984328

Navrotsky, Alexandra ^[1]

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1. University of California, Davis

Research performed on the program “New Fission Product Waste Forms: Development and Characterization,” in the last three years has fulfilled the objectives of the proposal which were to 1) establish ceramic waste forms for disposing of Cs, Sr and minor actinides, 2) fully characterize the phase relationships, structures and thermodynamic and kinetic stabilities of promising waste forms, 3) establish a sound technical basis for understanding key waste form properties, such as melting temperatures and aqueous durability, based on an in-depth understanding of waste form structures and thermochemistry, and 4) establish synthesis, testing, scaleup and commercialization routes for wasteform implementation through out in-kind collaborations. In addition, since Cs and Sr form new elements by radioactive decay, the behavior and thermodynamics of waste forms containing different proportions of Cs, Sr and their decay products were discovered using non-radioactive analogues. Collaborations among researchers from three institutions, UC Davis, Sandia National Laboratories, and Shott Inc., were formed to perform the primary work on the program. The unique expertise of each of the members in the areas of waste form development, structure/property relationships, hydrothermal and high temperature synthesis, crystal/glass production, and thermochemistry was critical to program success. In addition, collaborations with the Brigham Young Univeristy, Ben Gurion University, and Los Alamos National Laboratory, were established for standard entropies of ceramic waste forms, sol-gel synthesis, and high temperature synthesis. This work has had a significant impact in a number of areas. First, the studies of the thermodynamic stability of the mineral analogues provided an important technical foundation for assessment the viability of multicomponent oxide phases for Cs and Sr removal. Moreover, the thermodynamic data discovered in this program established information on the reaction pathways for the potential reaction products. The phase equilibria and thermodynamics involving the intermediates in the decay process in this program will assist in selection of the best process for Cs or Sr immobilization. In addition, data from the study can be used to develop engineering solutions for potential process upsets. Second, the glass – crystal stability of multicomponent oxide phases that were representative silicates on this program is highly distinguishable for mother compounds and decay products, thus providing a fundamental understanding on the separate effects from chemistry and from radiation. Finally, we have developed a foundation for understanding chemistry-structure-energetics relationships in titanosilicates that can be used to develop more effective materials.

• Research Organization: University of California, Davis, Davis, CA
• Sponsoring Organization: DOE
• DOE Contract Number: FC07-07ID14830
• OSTI ID: 984328
• Report Number(s): DOE/ID14830-1
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACTINIDES
CERAMICS
CHEMISTRY
COMMERCIALIZATION
DAUGHTER PRODUCTS
DECAY
FISSION PRODUCTS
IMPLEMENTATION
KINETICS
MELTING
OXIDES
REMOVAL
SILICATES
STABILITY
SYNTHESIS
TESTING
THERMODYNAMICS
VIABILITY
WASTE FORMS
cesium
decay products
glass-crystal stability
nuclear waste ceramics
strontium
thermodynamics (or thermodynamic stability)
titanosilicates