Technetium Immobilization Forms Literature Survey

Westsik, Joseph H. ; Cantrell, Kirk J. ; Serne, R. Jeffrey ; Qafoku, Nikolla

关键词: Technetium;    waste forms;    WTP;   

DOI  :  10.2172/1130666
RP-ID  :  PNNL-23329
RP-ID  :  EMSP-RPT-023
PID  :  OSTI ID: 1130666
Others  :  Other: EY4049110

美国|英语

来源: SciTech Connect

【 摘 要 】

Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.