Development and demonstration of a system for vitrifying high-level radioactive waste in high-silica glass

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6718082

Keene, W E

Preliminary testing of a high silica glass process suggested that requirements could be satisfied by fixing the waste in a high silica core surrounded by a waste-free high silica clad. This dissertation reports the development of the technology to execute the process remotely and the demonstration of the remote process, using simulated high level waste separated into sludge and clarified liquid phases comparable to the waste at the Savannah River Plant. An ion exchange medium consisting of porous glass matrix glass powder was used in batch mode to achieve liquid phase decontamination factors of approximately 39 for Sr-90, 7 for Co-60 and 5 for Cs-137. Following ion exchange, the decontaminated liquid was decanted; the sludge was added to the spent medium; the stirred mixture was vacuum dried at elevated temperature, and the resultant powder was transferred into a non-radioactive high silica glass tube. Programmed heating and pressure reduction calcined non-oxide components, collapsed the particles of porous glass to physically trap material in the pores, agglomerated the collapsed particles to trap inter-granular sludge particles, and collapsed the clad tube about the core. The technology developed for remote ion exchange and vitrification is shown to be satisfactory; some improvements are suggested. A short-term test demonstrated the leach rate from the waste form to be less than 10/sup -10/ y/sup -1/ for Cs-137 and less than 9 x 10/sup -9/ y/sup -1/ for Co-60; no measurement was made for Sr/Y-90. The high silica core and clad technology provides, by far, the most leach-resistant packaging which has been demonstrated for high level waste. In particular, the observed leach rates are very far below the US NRC criterion for a fractional release rate less than 10/sup -5/ y/sup -1/.

• Research Organization: Catholic Univ. of America, Washington, DC
• OSTI ID: 6718082
• Country of Publication: United States
• Language: English

Related Subjects

052001* -- Nuclear Fuels-- Waste Processing
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CESIUM 137
CESIUM ISOTOPES
CHALCOGENIDES
COBALT 60
COBALT ISOTOPES
DISSOLUTION
EVEN-EVEN NUCLEI
GLASS
HEAT TREATMENTS
HIGH-LEVEL RADIOACTIVE WASTES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ION EXCHANGE
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEACHING
LIQUID WASTES
MANAGEMENT
MATERIALS
MINERALS
MINUTES LIVING RADIOISOTOPES
NATIONAL ORGANIZATIONS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE TESTING
PROCESSING
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
RADIOISOTOPES
REMOTE HANDLING
SAVANNAH RIVER PLANT
SEPARATION PROCESSES
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SIMULATION
SLUDGES
STRONTIUM 90
STRONTIUM ISOTOPES
TESTING
US AEC
US DOE
US ERDA
US ORGANIZATIONS
VITRIFICATION
WASTE FORMS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
YEARS LIVING RADIOISOTOPES