Hanford Low-Activity Waste Processing: Demonstration of the Off-Gas Recycle Flowsheet - 13443
- Washington River Protection Solutions, LLC, Richland, WA 99532 (United States)
Vitrification of Hanford Low-Activity Waste (LAW) is nominally the thermal conversion and incorporation of sodium salts and radionuclides into borosilicate glass. One key radionuclide present in LAW is technetium-99. Technetium-99 is a low energy, long-lived beta emitting radionuclide present in the waste feed in concentrations on the order of 1-10 ppm. The long half-life combined with a high solubility in groundwater results in technetium-99 having considerable impact on performance modeling (as potential release to the environment) of both the waste glass and associated secondary waste products. The current Hanford Tank Waste Treatment and Immobilization Plant (WTP) process flowsheet calls for the recycle of vitrification process off-gas condensates to maximize the portion of technetium ultimately immobilized in the waste glass. This is required as technetium acts as a semi-volatile specie, i.e. considerable loss of the radionuclide to the process off-gas stream can occur during the vitrification process. To test the process flowsheet assumptions, a prototypic off-gas system with recycle capability was added to a laboratory melter (on the order of 1/200 scale) and testing performed. Key test goals included determination of the process mass balance for technetium, a non-radioactive surrogate (rhenium), and other soluble species (sulfate, halides, etc.) which are concentrated by recycling off-gas condensates. The studies performed are the initial demonstrations of process recycle for this type of liquid-fed melter system. This paper describes the process recycle system, the waste feeds processed, and experimental results. Comparisons between data gathered using process recycle and previous single pass melter testing as well as mathematical modeling simulations are also provided. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9-332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 22221410
- Report Number(s):
- INIS-US-13-WM-13443; TRN: US14V0607042365
- Resource Relation:
- Conference: Waste Management 2013 - WM2013 Conference: International collaboration and continuous improvement, Phoenix, AZ (United States), 24-28 Feb 2013; Other Information: Country of input: France; 13 refs.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BOROSILICATE GLASS
CONCENTRATION RATIO
GAS CONDENSATES
GROUND WATER
HALIDES
LOW-LEVEL RADIOACTIVE WASTES
RADIOACTIVE WASTE PROCESSING
RHENIUM
SIMULATION
SODIUM
SULFATES
TANKS
TECHNETIUM
TECHNETIUM 99
VITRIFICATION