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Hydrothermal reactions of fly ash. Quarterly report, October 1, 1993--December 31, 1993

Description: The reactions which occur when fly ash is treated under hydrothermal conditions are being Investigated. This is being done for two primary reasons. The first of these is to determine the nature of the phases that form, to assess the stabilities of these phases in the ambient environment and, finally, to assess whether these phases are capable of sequestering hazardous species. The second reason for undertaking this proposed study is that, depending on the composition of the ash and the presence of selected additives, it may be possible under hydrothermal conditions to form compounds which have cementitious properties. Formation of four classes of compounds, which bracket likely fly ash compositional ranges, have been selected for study. These are calcium silicate hydrates, calcium silicosulfates, calcium aluminosulfates, and alkali aluminosilicates. The specific compounds fabricated will be determined and their stability regions assessed. As a part of stability assessment, the extent to which selected hazardous species are sequestered will be determined. Finally, the cementing properties of these compounds will be established.
Date: May 1, 1994
Creator: Brown, P. W.
Partner: UNT Libraries Government Documents Department

Homogeneous Reactor Experiment (HRE) Pond cryogenic barrier technology demonstration: Pre-barrier subsurface hydrology and contaminant transport investigation

Description: The Homogeneous Reactor Experiment (HRE) Pond is the site of a former impoundment for radioactive wastes that has since been drained, filled with soil, and covered with an asphalt cap. The site is bordered to the east and south by a tributary that empties into Melton Branch Creek and that contains significant concentrations of radioactive contaminants, primarily {sup 90}Sr. Because of the proximity of the tributary to the HRE disposal site and the probable flow of groundwater from the site to the tributary, it is hypothesized that the HRE Pond is a source of contamination to he creek. As a means for temporary containment of contaminants within the impoundment, a cryogenic barrier technology demonstration was initiated in FY96 with a background hydrologic investigation that continued through FY97. Cryogenic equipment installation was completed in FY97, and freezing was initiated in September of 1997. This report documents the results of a hydrologic and geologic investigation of the HRE Pond/cryogenic barrier site. The purpose of this investigation is to evaluate the hydrologic conditions within and around the impoundment in order to meet the following objectives: (1) to provide a pre-barrier subsurface hydrologic baseline for post-barrier performance assessment; (2) to confirm that the impoundment is hydraulically connected to the surrounding sediments; and (3) to determine the likely contaminant exit pathways from the impoundment. The methods of investigation included water level and temperature monitoring in a network of wells and standpipes in and surrounding the impoundment, a helium tracer test conducted under ambient flow conditions, and geologic logging during the drilling of boreholes for installation of cryogenic probes and temperature monitoring wells.
Date: March 1, 1998
Creator: Moline, G.R.
Partner: UNT Libraries Government Documents Department

HRE-Pond Cryogenic Barrier Technology Demonstration: Pre- and Post-Barrier Hydrologic Assessment

Description: The Homogeneous Reactor Experiment (HRE) Pond is the site of a former impoundment for radioactive wastes on the Oak Ridge Reservation (ORR) in east Tennessee. The pond received radioactive wastes from 1957 to 1962, and was subsequently drained, filled with soil, and covered with an asphalt cap. The site is bordered to the east and south by an unnamed stream that contains significant concentrations of radioactive contaminants, primarily {sup 90}Sr. Because of the proximity of the stream to the HRE disposal site and the probable flow of groundwater from the site to the stream, it was hypothesized that the HRE Pond has been a source of contamination to the creek. The HRE-Pond was chosen as the site of a cryogenic barrier demonstration to evaluate this technology as a means for rapid, temporary isolation of contaminants in the type of subsurface environment that exists on the ORR. The cryogenic barrier is created by the circulation of liquid CO{sub 2} through a system of thermoprobes installed in boreholes which are backfilled with sand. The probes cool the subsurface, creating a vertical ice wall by freezing adjacent groundwater, effectively surrounding the pond on four sides. The purpose of this investigation was to evaluate the hydrologic conditions within and around the pond prior to, during, and after the cryogenic barrier emplacement. The objectives were (1) to provide a hydrologic baseline for post-banner performance assessment, (2) to confirm that the pond is hydraulically connected to the surrounding sediments, (3) to determine the likely contaminant exit pathways from the pond, and (4) to measure changes in hydrologic conditions after barrier emplacement in order to assess the barrier performance. Because relatively little information about the subsurface hydrology and the actual configuration of the pond existed, data from multiple sources was required to reconstruct this complex system.
Date: June 1, 1999
Creator: Moline, G. R.
Partner: UNT Libraries Government Documents Department

RCRA Facilities Assessment (RFA)---Oak Ridge National Laboratory

Description: US Department of Energy (DOE) facilities are required to be in full compliance with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established a Remedial Action Program (RAP) to provide comprehensive management of areas where past and current research, development, and waste management activities have resulted in residual contamination of facilities or the environment. This report presents the RCRA Facility Assessment (RFA) required to meet the requirements of RCRA Section 3004(u). Included in the RFA are (1) a listing of all sites identified at ORNL that could be considered sources of releases or potential releases; (2) background information on each of these sites, including location, type, size, period of operation, current operational status, and information on observed or potential releases (as required in Section II.A.1 of the RCRA permit); (3) analytical results obtained from preliminary surveys conducted to verify the presence or absence of releases from some of the sites; and (4) ORNL`s assessment of the need for further remedial attention.
Date: March 1, 1987
Partner: UNT Libraries Government Documents Department

RCRA Facilities Assessment (RFA)---Oak Ridge National Laboratory

Description: US Department of Energy (DOE) facilities are required to be in full compliance with all federal and state regulations. In response to this requirement, the Oak Ridge National Laboratory (ORNL) has established a Remedial Action Program (RAP) to provide comprehensive management of areas where past and current research, development, and waste management activities have resulted in residual contamination of facilities or the environment. This report presents the RCRA Facility Assessment (RFA) required to meet the requirements of RCRA Section 3004(u). Included in the RFA are (1) a listing of all sites identified at ORNL that could be considered sources of releases or potential releases; (2) background information on each of these sites, including location, type, size, period of operation, current operational status, and information on observed or potential releases (as required in Section II.A.1 of the RCRA permit); (3) analytical results obtained from preliminary surveys conducted to verify the presence or absence of releases from some of the sites; and (4) ORNL's assessment of the need for further remedial attention.
Date: March 1, 1987
Partner: UNT Libraries Government Documents Department