Technetium Inventory, Distribution, and Speciation in Hanford Tanks

Serne, R. Jeffrey ; Rapko, Brian M.

关键词: Technetium;    storage tanks;    waste forms;   

DOI  :  10.2172/1130665
RP-ID  :  PNNL-23319
RP-ID  :  EMSP-RPT-022
PID  :  OSTI ID: 1130665
Others  :  Other: EY4049110

美国|英语

来源: SciTech Connect

【 摘 要 】

The purpose of this report is three fold: 1) assemble the available information regarding technetium (Tc) inventory, distribution between phases, and speciation in Hanford???s 177 storage tanks into a single, detailed, comprehensive assessment; 2) discuss the fate (distribution/speciation) of Tc once retrieved from the storage tanks and processed into a final waste form; and 3) discuss/document in less detail the available data on the inventory of Tc in other "pools" such as the vadose zone below inactive cribs and trenches, below single-shell tanks (SSTs) that have leaked, and in the groundwater below the Hanford Site. A thorough understanding of the inventory for mobile contaminants is key to any performance or risk assessment for Hanford Site facilities because potential groundwater and river contamination levels are proportional to the amount of contaminants disposed at the Hanford Site. Because the majority of the total 99Tc produced at Hanford (~32,600 Ci) is currently stored in Hanford???s 177 tanks (~26,500 Ci), there is a critical need for knowledge of the fate of this 99Tc as it is removed from the tanks and processed into a final solid waste form. Current flow sheets for the Hanford Waste Treatment and Immobilization Plant process show most of the 99Tc will be immobilized as low-activity waste glass that will remain on the Hanford Site and disposed at the Integrated Disposal Facility (IDF); only a small fraction will be shipped to a geologic repository with the immobilized high-level waste. Past performance assessment studies, which focused on groundwater protection, have shown that 99Tc would be the primary dose contributor to the IDF performance.