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Title: Stability of high-level waste forms. 1998 annual progress report

Technical Report ·
DOI:https://doi.org/10.2172/13683· OSTI ID:13683
;  [1];  [2]
  1. Oak Ridge National Lab., TN (US)
  2. Pennsylvania State Univ., PA (US)

'The objective of this program is to identify new waste forms and disposal strategies specific to crystalline silicotitanate (CST) secondary waste that is generated from Cs and Sr ion exchange processes. In particular, in-situ heat treatment of CSTs to produce an alternate waste form is being examined. Waste forms that are developed in this work will offer an alternative to current disposal plans which call for recombining the separated Cs, Sr-loaded CST into the high activity waste streams then dissolving it in borosilicate glass. The goals of the program are to reduce the costs associated with CST waste disposal, to minimize the risk of contamination to the environment during CST processing, and to provide DOE with technical alternatives for CST disposal. Because there is uncertainty in repository availability and in waste acceptance criteria, it is likely that Cs and Sr loaded ion exchangers will require short term storage at Hanford or that new scenarios for long term storage or disposal of nuclides with relatively short half lives (such as {sup 137}Cs and {sup 90}Sr) will arise. Research activities in this program will generate information on the durabilities and stabilities of thermally consolidated CSTs so that the potential of these options as viable storage or disposal scenarios can be evaluated. The technical objectives of the proposed work are to fully characterize the phase relationships, structures and thermodynamic and kinetic stabilities of crystalline silicotitanate waste forms and to establish a sound technical basis for understanding key waste form properties, such as melting temperatures and aqueous durability, based on an in-depth understanding of waste form structures and thermochemistry. This report summarizes work after seven months of a three year program.'

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Environmental Management (EM), Office of Science and Risk Policy
OSTI ID:
13683
Report Number(s):
EMSP-60020-98; ON: DE00013683
Country of Publication:
United States
Language:
English