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Title: Mineral assemblage transformation of a metakaolin-based waste form after geopolymer encapsulation

Current plans for nuclear waste vitrification at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) lack the capacity to treat all of the low activity waste (LAW) that is not encapsulated in the vitrified product. Fluidized Bed Steam Reforming (FBSR) is one of the supplemental technologies under consideration to fill this gap. The FBSR process results in a granular product mainly composed of feldspathoid mineral phases that encapsulate the LAW and other contaminants of concern (COCs). In order to better understand the characteristics of the FBSR product, characterization testing has been performed on the granular product as well as the granular product encapsulated in a monolithic geopolymer binder. The non-radioactive simulated tank waste samples created for use in this study are the result of a 2008 Department of Energy sponsored Engineering Scale Technology Demonstration (ESTD) in 2008. These samples were created from waste simulant that was chemically shimmed to resemble actual tank waste, and rhenium has been used as a substitute for technetium. Another set of samples was created by the Savannah River Site Bench-Scale Reformer (BSR) using a chemical shim of Savannah River Site Tank 50 waste in order to simulate a blend of 68 Hanford tank wastes.more » This paper presents results from coal and moisture removal tests along with XRD, SEM, and BET analyses showing that the major mineral components are predominantly sodium aluminosilicate minerals and that the mineral product is highly porous. Results also show that the materials pass the short-term leach tests: the Toxicity Characteristic Leaching Procedure (TCLP) and Product Consistency Test (PCT).« less
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Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0022-3115; EY4049110
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Materials; Journal Volume: 473
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Low-Activity Waste; Fluidized Bed Steam Reformer; Supplemental Immobilization; Feldspathoid Minerals; Waste Form Leach Test