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High volume-high value usage of flue gas desulfurization (FGD) by-products in underground mines: Phase 2 -- Field investigations. Quarterly report, January 1--March 31, 1998

Description: The factors that control the strength of FBC ash grout were the focus of work during this quarter. Samples were prepared at different water contents and placed into cylindrical PVC molds. At specified curing intervals, the grout cylinders were subjected to unconfined compressive strength testing as per procedures described in previous reports. Chemical, mineralogical, and microscopical analyses were also conducted on the samples. It was found that higher curing temperatures significantly increase the strength gain rate of the FBC ash grout, in agreement with earlier results. As expected, water content also exerts a strong influence on the strength of the grout. The compressive strength data obtained for the laboratory-prepared samples are in excellent agreement with strength data obtained on grout placed in auger holes during the field demonstrations. The data also indicate that the field samples suffered negligible deterioration over the course of the curing period in the auger holes. Analysis of the laboratory prepared grout samples using XRD revealed a mineralogy similar to the field samples. A correspondence between ettringite abundance and compressive strength was observed only during grout curing. The formation of minerals such as ettringite is apparently a good indication that curing reactions are progressing and that the grout strength is increasing, but mineral distribution by itself does not explain or predict final strength. The microscopy data, in combination with geotechnical and XRD data, suggest that the strength of the grout is largely a function of the density of an amorphous (or finely crystalline) material that comprises the majority of the cured grout. Therefore, an increase in density of this material results in an increase in grout strength.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department


Description: Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.
Date: November 1, 1998
Partner: UNT Libraries Government Documents Department

Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

Description: Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter, the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.
Date: April 1, 1995
Creator: Kruger, A.A.; Olson, R.A. & Tennis, P.D.
Partner: UNT Libraries Government Documents Department


Description: Closed loop vertical boreholes used with geothermal heat pumps are grouted to facilitate heat transfer and prevent ground water contamination. The grout must exhibit suitable thermal conductivity as well as adequate hydraulic sealing characteristics. Permeability and infiltration tests were performed to assess the ability of cementitious grout to control vertical seepage in boreholes. It was determined that a superplasticized cement-sand grout is a more effective borehole sealant than neat cement over a range of likely operational temperatures. The feasibility of using non-destructive methods to verify bonding in heat exchangers is reviewed.
Date: October 1, 1999
Creator: Allan, M. L. & Philippacopoulos, A. J.
Partner: UNT Libraries Government Documents Department

Geothermal heat pump grouting materials

Description: The thermal conductivity of cementitious grouts has been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. The cement-sand grouts were also tested for rheological characteristics, bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the thermal conductivity, permeability, bonding and exotherm data for selected cementitious grouts. The theoretical reduction in bore length that could be achieved with the BNL-developed cement-sand grouts is examined. Finally, the FY 98 research and field trials are discussed.
Date: August 1, 1998
Creator: Allan, M.
Partner: UNT Libraries Government Documents Department

High performance CLSM field mixing and pumping test results

Description: An improved low bleed water CLSM mix was field tested on May 13, 1997 at the Throop portable auger batching plant. Production and pumping tests were very successful. The four cubic yards of material pumped into a ply wood form where it flowed 48 feet (the entire length of the form). The CLSM slurry was very uniform, self leveling, cohesive, showed no segregation, and had no bleed water. Properties of the High Performance CLSM were the same for material collected at the auger and at the end of the pipeline except for the air content which was 5.5% at the auger and 3.2% at the end of the pipeline. This is exactly what was expected and indicates that this CLSM is easy to mix and pump in the Throop/BSRI equipment. CLSM Mix TW-10 is recommended for Tank Closure based on the field batching and pumping tests.
Date: May 14, 1997
Creator: Rajendran, N. & Langton, C.A.
Partner: UNT Libraries Government Documents Department

Injection of FGD Grout to Abate Acid Mine Drainage in Underground Coal Mines

Description: Acid Mine Drainage (AMD) from abandoned underground coal mines in Ohio is a concern for both residents and regulatory agencies. Effluent from these mines is typically characterized by low pH and high iron and sulfate concentrations and may contaminate local drinking-water supplies and streams. The objective of this project is to demonstrate the technical feasibility of injecting cementitious alkaline materials, such as Flue Gas Desulfurization (FGD) material to mitigate current adverse environmental impacts associated with AMD in a small, abandoned deep mine in Coshocton County Ohio. The Flue Gas Desulfurization material will be provided from American Electric Power`s (AEP) Conesville Plant. It will be injected as a grout mix that will use Fixated Flue Gas Desulfurization material and water. The subject site for this study is located on the border of Coshocton and Muskingum Counties, Ohio, approximately 1.5 miles south-southwest of the town of Wills Creek. The study will be performed at an underground mine designated as Mm-127 in the Ohio Department of Natural Resources register, also known as the Roberts-Dawson Mine. The mine operated in the mid-1950s, during which approximately 2 million cubic feet of coal was removed. Effluent discharging from the abandoned mine entrances has low pH in the range of 2.8-3.0 that drains directly into Wills Creek Lake. The mine covers approximately 14.6 acres. It is estimated that 26,000 tons of FGD material will be provided from AEP`s Conesville Power Plant located approximately 3 miles northwest of the subject site.
Date: July 1, 1997
Creator: Mafi, S.; Damian, M.T.; Senita, R.E.; Jewitt, W.C.; Bair, S.; Chin, Y.C. et al.
Partner: UNT Libraries Government Documents Department

Annual report of decommissioning and remedial action S&M activities for the Environmental Management Program at Oak Ridge National Laboratory, Oak Ridge, Tennessee

Description: The Oak Ridge National Laboratory (ORNL) Surveillance and Maintenance (S&M) Program performs a variety of activities to ensure that sites and facilities within its responsibility remain in a safe condition and in compliance with applicable regulations. All S&M Program activities during fiscal year (FY) 1997 were accomplished safely, with no health and safety incidents, no lost work days, and no environmental noncompliances. In addition, all activities were performed within schedule thresholds and under budget. Many remedial action (RA) sites and decontamination and decommissioning (D&D) facilities are inspected and maintained by the S&M Program. RA sites encompass approximately 650 acres and 33 D&D facilities, including 4 inactive reactors. During FY 1997, routine, preventative, and emergency maintenance activities were performed as needed at these sites and facilities. Stabilization activities were also performed to reduce risks and reduce future S&M costs. Major activities at the RA sites during FY 1997 included maintaining proper liquid levels in surface impoundments and inactive -liquid low-level waste storage tanks as well as installing a new cover at the tumulus pads in Waste Area Grouping (WAG) 6, planting trees in the First Creek Riparian Corridor, and performing over 900 well inspections. Postremediation monitoring was conducted at the 3001 Canal, Core Hole 8, the WAG 6 Resource Conservation and Recovery caps, and WAG 5 Seeps C and D; groundwater monitoring was performed in WAGs 4, 5, and 6 and at the 3001 Canal Well. At ORNL D&D facilities, significant accomplishments included contaminated lead brick removal, asbestos abatement, contaminated equipment and debris removal, and radiologically contaminated area painting.
Date: November 1, 1997
Partner: UNT Libraries Government Documents Department

Utilization of the MPI Process for in-tank solidification of heel material in large-diameter cylindrical tanks

Description: A major problem faced by the US Department of Energy is remediation of sludge and supernatant waste in underground storage tanks. Exhumation of the waste is currently the preferred remediation method. However, exhumation cannot completely remove all of the contaminated materials from the tanks. For large-diameter tanks, amounts of highly contaminated ``heel'' material approaching 20,000 gal can remain. Often sludge containing zeolite particles leaves ``sand bars'' of locally contaminated material across the floor of the tank. The best management practices for in-tank treatment (stabilization and immobilization) of wastes require an integrated approach to develop appropriate treatment agents that can be safely delivered and mixed uniformly with sludge. Ground Environmental Services has developed and demonstrated a remotely controlled, high-velocity jet delivery system termed, Multi-Point-Injection (MPI). This robust jet delivery system has been field-deployed to create homogeneous monoliths containing shallow buried miscellaneous waste in trenches [fiscal year (FY) 1995] and surrogate sludge in cylindrical (FY 1998) and long, horizontal tanks (FY 1999). During the FY 1998 demonstration, the MPI process successfully formed a 32-ton uniform monolith of grout and waste surrogates in about 8 min. Analytical data indicated that 10 tons of zeolite-type physical surrogate were uniformly mixed within a 40-in.-thick monolith without lifting the MPI jetting tools off the tank floor. Over 1,000 lb of cohesive surrogates, with consistencies similar to Gunite and Associated Tank (GAAT) TH-4 and Hanford tank sludges, were easily intermixed into the monolith without exceeding a core temperature of 100 F during curing.
Date: January 1, 2000
Creator: Kauschinger, J.L. & Lewis, B.E.
Partner: UNT Libraries Government Documents Department

Horizontal grout barrier project results of the latest testing

Description: Throughout United States Department of Energy (DOE) sites are situations where storage tanks and pits are leaking or have the potential to leak contamination into the soil. Subsequent leaching from rain and groundwater flow disperses the contamination far from the original site and, in some cases, into aquifers which serve as a drinking water source. Fernald Environmental Restoration Management Corporation (FERMCO) at Fernald working with the DOE Office of Technology Development (OTD) and two subcontractors, is pursuing the goal of placing a barrier beneath the contamination to prevent this dispersion. The technology being developed is an in situ approach based on directional drilling and jet grouting techniques developed in the oil fields. The unique barrier techniques being developed depend on innovative tooling and special grouts to install a horizontal barrier underground without disturbing the contaminated soils above. The initial tool designs were tested in December 1992 and were encouraging enough that the DOE agreed to fund continued development. A second set of designs were tested in August 1994. The testing results were less than expected but did provide a number of lessons learned. This paper reports on the third set of tool designs and the results of testing these tools prior to the full demonstration project at Fernald.
Date: March 1, 1995
Creator: Riedel, K.W.; Ridenour, D.E. & Walker, J.
Partner: UNT Libraries Government Documents Department

Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications

Description: Preliminary studies were preformed to determine whether thermal conductivity of cementitious grouts used to backfill heat exchanger loops for geothermal heat pumps could be improved, thus improving efficiency. Grouts containing selected additives were compares with conventional bentonite and cement grouts. Significant enhancement of grout alumina grit, steel fibers, and silicon carbide increased the thermal conductivity when compared to unfilled, high solids bentonite grouts and conventional cement grouts. Furthermore, the developed grouts retained high thermal conductivity in the dry state, where as conventional bentonite and cement grouts tend to act as insulators if moisture is lost. The cementitious grouts studied can be mixed and placed using conventional grouting equipment.
Date: June 1, 1996
Creator: Allan, M.L.
Partner: UNT Libraries Government Documents Department

Pore solution chemistry of simulated low-level liquid waste incorporated in cement grouts

Description: Expressed pore solutions from simulated low level liquid waste cement grouts cured at room temperature, 50{degree}C and 90{degree}C for various duration were analyzed by standard chemical methods and ion chromatography. The solid portions of the grouts were formulated with portland cement, fly ash, slag, and attapulgite clay in the ratios of 3:3:3:1. Two different solutions simulating off-gas condensates expected from vitrification of Hanford low level tank wastes were made. One is highly alkaline and contains the species Na{sup {plus}}, P0{sub 4}{sup 3-}, N0{sub 2}{sup -}, NO{sub 3}{sup -} and OH{sup -}. The other is carbonated and contains the species, Na{sup {plus}}, PO{sub 4}{sup 3-}, NO{sub 2}{sup -}, NO{sub 3}{sup -}, and CO{sub 3}{sup 2-}. In both cases phosphate rapidly disappeared from the pore solution, leaving behind sodium in the form of hydroxide. The carbonates were also removed from the pore solution to form calcium carbonate and possibly calcium monocarboaluminate. These reactions resulted in the increase of hydroxide ion concentration in the early period. Subsequently there was a significant reduction OH{sup -} and Na{sup {plus}} ion concentrations. In contrast high concentration of N0{sub 2}{sup -} and N0{sub 3}{sup -} were retained in the pore solution indefinitely.
Date: December 1, 1995
Creator: Kruger, A.A.
Partner: UNT Libraries Government Documents Department

Success in horizontal barrier developments

Description: A successful proof of concept demonstration has been conducted of operational methods and tooling for the in situ construction of underground horizontal barriers for the control and containment of groundwater and contamination. The method involves jet grouting with specially adapted tools guided between twin, parallel wells for the placement of a grout beneath a waste site. The objective of the work is to develop reliable methods of constructing extensive, competent horizontal barriers underneath waste sites without excavating or penetrating the waste during the process.
Date: June 1, 1996
Creator: Pettit, P.J.; Ridenour, D.E. & Jalovec, J.
Partner: UNT Libraries Government Documents Department

Latex-modified grouts for in-situ stabilization of buried transuranic/mixed waste

Description: The Department of Applied Science at Brookhaven national Laboratory was requested to investigate latex-modified grouts for in-situ stabilization of buried TRU/mixed waste for INEL. The waste exists in shallow trenches that were backfilled with soil. The objective was to formulate latex-modified grouts for use with the jet grouting technique to enable in-situ stabilization of buried waste. The stabilized waste was either to be left in place or retrieved for further processing. Grouting prior to retrieval reduces the potential release of contaminants. Rheological properties of latex-modified grouts were investigated and compared with those of conventional neat cement grouts used for jet grouting.
Date: June 1, 1996
Creator: Allan, M.L.
Partner: UNT Libraries Government Documents Department

A field test of permeation grouting in heterogeneous soils using a new generation of barrier liquids

Description: A field demonstration of permeation grouting was conducted at a gravel quarry near Los Banos, California, with the purpose of demonstrating the feasibility of the concept. Two grouts were used: a form of colloidal silica that gels after the addition of a gelling agent, and a polysiloxane that polymerizes after the addition of a catalyst. Both create relatively impermeable barriers in response to the large increase in viscosity during gelation or polymerization, respectively. The grouts were successfully injected at a depth between 10 and 14ft. Subsequent exhumation of the injected gravels revealed that both grouts produced relatively uniform bulbs. Laboratory measurements of the grouted material retrieved from the field showed at least a four order of magnitude reduction in permeability over the ungrouted material.
Date: August 1995
Creator: Moridis, G. J.; Persoff, P.; Apps, J. A.; Myer, L.; Pruess, K. & Yen, P.
Partner: UNT Libraries Government Documents Department


Description: The thermal conductivity of cementitious grouts has been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. The cement-sand grouts were also tested for rheological characteristics, bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the thermal conductivity, permeability, bonding and exotherm data for selected cementitious grouts. The theoretical reduction in bore length that could be achieved with the BNL-developed cement-sand grouts is examined. Finally, the FY 98 research and field trials are discussed.
Date: April 1, 1998
Creator: ALLAN,M.
Partner: UNT Libraries Government Documents Department

Corrective Action Decision Document for Corrective Action Unit 322: Areas 1 and 3 Release Sites and Injection Wells Nevada Test Site, Nevada, Rev. No. 0

Description: This Corrective Action Decision Document has been prepared for Corrective Action Unit (CAU) 322, Areas 1 and 3 Release Sites and Injection Wells, Nevada Test Site, Nevada, in accordance with the ''Federal Facility Agreement and Consent Order'' (1996). Corrective Action Unit 322 is comprised of the following corrective action sites (CASs): (1) 01-25-01 - AST Release Site; (2) 03-25-03 - Mud Plant and AST Diesel Release; and (3) 03-20-05 - Injection Wells and BOP Shop. The purpose of this Corrective Action Decision Document is to identify and provide the rationale for the recommendation of a corrective action alternative for each CAS within CAU 322. Corrective action investigation activities were performed from April 2004 through September 2004, as set forth in the Corrective Action Investigation Plan. The purposes of the activities as defined during the data quality objectives process were: (1) Determine if contaminants of concern (COCs) are present; (2) If COCs are present, determine their nature and extent; and (3) Provide sufficient information and data to recommend appropriate corrective actions for the CASs. Analytes detected during the corrective action investigation were evaluated against appropriate preliminary action levels to identify contaminants of concern for each corrective action site. Radiological field measurements were compared to unrestricted release criteria. Assessment of the data generated from investigation activities revealed the following: (1) CAS 01-25-01 contains an AST berm contaminated with total petroleum hydrocarbons (TPH) diesel-range organics (DRO). (2) CAS 03-25-03 includes two distinct areas: Area A where no contamination remains from a potential spill associated with an AST, and Area B where TPH-DRO contamination associated with various activities at the mud plant was identified. The Area B contamination was found at various locations and depths. (3) CAS 03-25-03 Area B contains TPH-DRO contamination at various locations and depths in the area associated with the ...
Date: December 1, 2004
Creator: Boehlecke, Robert
Partner: UNT Libraries Government Documents Department

An Order-of-Magnitude Estimation of Benzene Concentration in Saltstone Vault

Description: The contents of Tank 48 that include the tetraphenylborate (TPB) precipitates of potassium and cesium will be grouted and stored in the Saltstone vault. The grouting process is exothermic, which should accelerate the decomposition of TPB precipitates eventually to benzene. Because the vault is not currently outfitted with an active ventilation system, there is a concern that a mixture of flammable gases may form in the vapor space of each cell filled with the curing grout. The purpose of this study was to determine if passive breathing induced by the diurnal oscillations of atmospheric pressure would provide any mitigating measure against potential flammability. Specifically, it was requested that a set of algorithms be developed that would predict the equilibrium concentration of benzene as a function of benzene generation rate, fill height, and the amplitude of the barometric pressure oscillations. These algorithms were to be derived based on several simplifying assumptions so that order of magnitude estimates could be made quickly for scoping purposes. This memo documents the resulting algorithms along with those key assumptions made. These algorithms were then applied to simulate several test cases, including the baseline case where the cell was filled to the maximum height of 25 ft at the bulk benzene generation rate of 3.4 g/hr.
Date: February 28, 2005
Partner: UNT Libraries Government Documents Department

Extrapolation of creep behavior of high-density polyethylene liner in the Catch Basin of grout vaults

Description: Testing was performed to determine if gravel particles will creep into and puncture the high-density polyethylene (HDPE) liner in the catch basin of a grout vault over a nominal 30-year period. Testing was performed to support a design without a protective geotextile cover after the geotextile was removed from the design. Recently, a protective geotextile cover over the liner was put back into the design. The data indicate that the geotextile has an insignificant effect on the creep of gravel into the liner. However, the geotextile may help to protect the liner during construction. Two types of tests were performed to evaluate the potential for creep-related puncture. In the first type of test, a very sensitive instrument measured the rate at which a probe crept into HDPE over a 20-minute period at temperatures of 176{degrees}F to 212{degrees}F (80{degrees}C to 100{degrees}C). The second type of test consisted of placing the liner between gravel and mortar at 194{degrees}F (90{degrees}C) and 45.1 psi overburden pressure for periods up to 1 year. By combining data from the two tests, the long-term behavior of the creep was extrapolated to 30 years of service. After 30 years of service, the liner will be in a nearly steady condition and further creep will be extremely small. The results indicate that the creep of gravel into the liner will not create a puncture during service at 194{degrees}F (90{degrees}C). The estimated creep over 30 years is expected to be less than 25 mils out of the total initial thickness of 60 mils. The test temperature of 194{degrees}F (90{degrees}C) corresponds to the design basis temperature of the vault. Lower temperatures are expected at the liner, which makes the test conservative. Only the potential for failure of the liner resulting from creep of gravel is addressed in this report.
Date: July 1, 1995
Creator: Whyatt, G.A.
Partner: UNT Libraries Government Documents Department

Chemical Grouting Lost-Circulation Zones with Polyurethane Foam

Description: Sandia National Laboratories is developing polyurethane foam as a chemical grout for lost circulation zones. In past work polyurethane foam was tried with limited success in laboratory tests and GDO sponsored field tests. Goals were that the foam expanded significantly and harden to a chillable firmness quickly. Since that earlier work there have been improvements in polyurethane chemistry and the causes of the failures of previous tests have been identified. Recent success in applying pure solution grouts (proper classification of polyurethane--Naudts) in boreholes encourages reevaluating its use to control lost circulation. These successes include conformance control in the oil patch (e.g. Ng) and darn remediation projects (Bruce et al.). In civil engineering, polyurethane is becoming the material of choice for sealing boreholes with large voids and high inflows, conditions associated with the worst lost circulation problems. Demonstration of a delivery mechanism is yet to be done in a geothermal borehole.
Date: July 12, 1999
Creator: Mansure, A.J. & Westmoreland, J.J.
Partner: UNT Libraries Government Documents Department

Numerical Simulations of Leakage from Underground LPG Storage Caverns

Description: To secure a stable supply of petroleum gas, underground storage caverns for liquified petroleum gas (LPG) are commonly used in many countries worldwide. Storing LPG in underground caverns requires that the surrounding rock mass remain saturated with groundwater and that the water pressure be higher than the liquid pressure inside the cavern. In previous studies, gas containment criteria for underground gas storage based on hydraulic gradient and pressure have been discussed, but these studies do not consider the physicochemical characteristics and behavior of LPG such as vaporization and dissolution in groundwater. Therefore, while these studies are very useful for designing storage caverns, they do not provide better understanding of the either the environmental effects of gas contamination or the behavior of vaporized LPG. In this study, we have performed three-phase fluid flow simulations of gas leakage from underground LPG storage caverns, using the multiphase multicomponent nonisothermal simulator TMVOC (Pruess and Battistelli, 2002), which is capable of solving the three-phase nonisothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. A two-dimensional cross-sectional model resembling an actual underground LPG facility in Japan was developed, and gas leakage phenomena were simulated for three different permeability models: (1) a homogeneous model, (2) a single-fault model, and (3) a heterogeneous model. In addition, the behavior of stored LPG was studied for the special case of a water curtain suddenly losing its function because of operational problems, or because of long-term effects such as clogging of boreholes. The results of the study indicate the following: (1) The water curtain system is a very powerful means for preventing gas leakage from underground storage facilities. By operating with appropriate pressure and layout, gas containment can be ensured. (2) However , in highly heterogeneous media such as fractured rock ...
Date: September 1, 2004
Creator: Yamamoto, Hajime & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Assessment of the Potential for Hydrogen Generation During Deactivation and Decommissioning of Reactor Vessels at the Savannah River Site

Description: The R- and P-reactor vessels at the Savannah River Site (SRS) are being prepared for deactivation and decommissioning (D&D). D&D activities will consist primarily of physically isolating and stabilizing the reactor vessel by filling it with a grout material. The reactor vessels contain aluminum alloy materials, which pose a concern in that aluminum corrodes rapidly when it comes in contact with the alkaline grout. A product of the corrosion reaction is hydrogen gas and therefore potential flammability issues were assessed. A model was developed to calculate the hydrogen generation rate as the reactor is being filled with the grout material. Three options existed for the type of grout material for D&D of the reactor vessels. The grout formulation options included ceramicrete (pH 6-8), a calcium aluminate sulfate (CAS) based cement (pH 10), or Portland cement grout (pH 12.4). Corrosion data for aluminum in concrete were utilized as input for the model. The calculations considered such factors as the surface area of the aluminum components, the open cross-sectional area of the reactor vessel, the rate at which the grout is added to the reactor vessel, and temperature. Given the hydrogen generation rate, the hydrogen concentration in the vapor space of the reactor vessel above the grout was calculated. This concentration was compared to the lower flammability limit for hydrogen. The assessment concluded that either ceramicrete or the CAS grout may be used to safely grout the P-reactor vessel. The risk of accumulation of a flammable mixture of hydrogen between the grout-air interface and the top of the reactor is very low. Portland cement grout, on the other hand, for the same range of process parameters did not provide a margin of safety against the accumulation of flammable gas in the reactor vessel during grouting operations in the P-reactor vessel. Therefore, it ...
Date: November 10, 2010
Creator: Wiersma, B.; Serrato, M. & Langton, C.
Partner: UNT Libraries Government Documents Department


Description: The Saltstone Production Facility (SPF) receives waste from Tank 50H for treatment. In the first quarter of the 2010 calendar year (1QCY10), Tank 50H accepted transfers of approximately 32 kgal from the Effluent Treatment Project (ETP), approximately 10 kgal from Tank 710 - the H-Canyon General Purpose Evaporator, approximately 32 kgal from the H-Canyon Super Kukla campaign, and approximately 26 kgal from the Modular Caustic Side Solvent Extraction Unit (MCU) Decontaminated Salt Solution Hold Tank (DSS-HT). The Saltstone Grout Sampling plan provides the South Carolina Department of Health and Environmental Control (SCDHEC) with the chemical and physical characterization strategy for the salt solution which is to be disposed of in the Z-Area Solid Waste Landfill (ISWLF). During operation, samples were collected from Tank 50H and grout samples prepared to determine the non-hazardous nature of the grout to meet the requirements of the South Carolina Hazardous Waste Management Regulations (SCHWMR) R.61-79.261.24(b) and R.61-79.268.48(a). Savannah River National Laboratory (SRNL) was asked to prepare saltstone from samples of Tank 50H obtained January 8, 2010 during 1QCY10 to determine the non-hazardous nature of the grout. The samples were cured and shipped to Babcock & Wilcox Technical Services Group-Radioisotope and Analytical Chemistry Laboratory (B&W TSG-RACL) to perform the Toxic Characteristic Leaching Procedure (TCLP) and subsequent extract analysis on saltstone samples for the analytes required for the quarterly analysis saltstone sample. In addition to the eight toxic metals - arsenic, barium, cadmium, chromium, mercury, lead, selenium and silver - analytes included the underlying hazardous constituents (UHC) antimony, beryllium, nickel, and thallium which could not be eliminated from analysis by process knowledge. B&W TSG-RACL provided subsamples to GEL Laboratories, LLC for analysis for the UHCs benzene, phenols and total and amenable cyanide.
Date: June 2, 2010
Creator: Reigel, M.
Partner: UNT Libraries Government Documents Department


Description: The U.S. Department of Energy (DOE) is conducting in situ closures (entombment) at a large number of facilities throughout the complex. Among the largest closure actions currently underway are the closures of the P and R Reactors at the Savannah River Site (SRS), near Aiken, South Carolina. In these facilities, subgrade open spaces are being stabilized with grout; this ensures the long term structural integrity of the facilities and permanently immobilizes and isolates residual contamination. The large size and structural complexity of these facilities present a wide variety of challenges for the identification and selection of appropriate fill materials. Considerations for grout formulations must account for flowability, long term stability, set times, heat generation and interactions with materials within the structure. The large size and configuration of the facility necessitates that grout must be pumped from the exterior to the spaces to be filled, which requires that the material must retain a high degree of flowability to move through piping without clogging while achieving the required leveling properties at the pour site. Set times and curing properties must be controlled to meet operations schedules, while not generating sufficient heat to compromise the properties of the fill material. The properties of residual materials can result in additional requirements for grout formulations. If significant quantities of aluminum are present in the facility, common formulations of highly alkaline grouts may not be appropriate because of the potential for hydrogen generation with the resultant risks. SRS is developing specialized inorganic grout formulations that are designed to address this issue. One circum-neutral chemical grout formulation identified for initial consideration did not possess the proper chemical characteristics, having exceptionally short set times and high heat of hydration. Research efforts are directed toward developing grout formulations that can meet operational requirements for chemical compatibility, extended set times ...
Date: August 25, 2010
Creator: Gladden, J.; Serrato, M.; Langton, C.; Long, T.; Blankenship, J.; Hannah, G. et al.
Partner: UNT Libraries Government Documents Department