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Title: Leaching of saltstone: Laboratory and field testing and mathematical modeling

Conference ·
OSTI ID:6271448

A low-level alkaline salt solution will be a byproduct in the processing of high-level waste at the Savannah River Plant (SRP). This solution will be incorporated into a wasteform, saltstone, and disposed of in surface vaults. Laboratory and field leach testing and mathematical modeling have demonstrated the predictability of contaminant release from cement wasteforms. Saltstone disposal in surface vaults will meet the design objective, which is to meet drinking water standards in shallow groundwater at the disposal area boundary. Diffusion is the predominant mechanism for release of contaminants to the environment. Leach testing in unsaturated soil, at soil moisture levels above 1 wt %, has shown no difference in leach rate compared to leaching in distilled water. Field leach testing of three thirty-ton blocks of saltstone in lysimeters has been underway since January 1984. Mathematical models were applied to assess design features for saltstone disposal. One dimensional infinite-composite and semi-infinite analytical models were developed for assessing diffusion of nitrate from saltstone through a cement barrier. Numerical models, both finite element and finite difference, were validated by comparison of model predictions with the saltstone lysimeter results. Validated models were used to assess the long-term performance of the saltstone stored in surface vaults. The maximum concentrations of all contaminants released from saltstone to shallow groundwater are predicted to be below drinking water standards at the disposal area boundary. 5 refs., 11 figs., 5 tabs.

Research Organization:
Savannah River Lab., Aiken, SC (USA)
DOE Contract Number:
AC09-76SR00001
OSTI ID:
6271448
Report Number(s):
DP-MS-87-32-Rev.1; CONF-870802-14-Rev.1; ON: DE87014197
Resource Relation:
Conference: 194. American Chemical Society national meeting, New Orleans, LA, USA, 30 Aug 1987; Other Information: Portions of this document are illegible in microfiche products
Country of Publication:
United States
Language:
English