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Vitrification of Rocky Flats ash followed by encapsulation in the Defense Waste Processing Facility

Description: The Department of Energy (DOE) manages approximately 10 to 20 metric tons of plutonium in the form of scrap, residues, oxides, ash, metal, sludge, compounds, etc. Not all of this material is chemically stable or is packaging acceptable for storage. Thus, it constitutes a potential hazard to employees and to the public. This paper describes a relatively simple concept for stabilizing most of this type of plutonium by converting it into encapsulated glass. A full-scale hot demonstration of the concept is proposed, in which Rock Flats ash would be vitrified and sealed in small cans, followed by encapsulation of the cans in Defense Waste Processing Facility canisters with high-level glass.
Date: June 1, 1996
Creator: Becker, G.W. Jr. & McKibben, J.M.
Partner: UNT Libraries Government Documents Department

SRTC monthly report, May 1995

Description: This report from the Savannah River Technology Center contains brief summaries of many projects ongoing at the center. Various aspects of tritium processing, separations work, environmental projects, and waste management are described. An in depth Executive Summary clearly analyzes current projects.
Date: May 1, 1995
Creator: Ferrell, J.M.
Partner: UNT Libraries Government Documents Department

Waste vitrification projects throughout the US initiated by SRS

Description: Technologies are being developed by the US Department of Energy (DOE) Nuclear Facility sites to convert high-level, low-level, and mixed wastes to a solid stabilized waste form for permanent disposal. Vitrification is one of the most important and environmentally safest technologies being developed. The Environmental Protection Agency (EPA) has declared vitrification the Best Demonstrated Available Technology (BDAT) for high-level radioactive waste and produced a Handbook of Vitrification Technologies for Treatment of Hazardous and Radioactive Waste. The Defense Waste Processing Facility (DWPF) being tested at Savannah River Site (SRS) will soon begin vitrifying the high-level waste at SRS. The DOE Office of Technology Development (OTD) has taken the position that mixed waste needs to be stabilized to the highest level reasonably possible to ensure that the resulting waste forms will meet both the current and future regulatory specifications. Vitrification produces durable waste forms at volume reductions up to 97%. Large reductions in volume minimize long-term storage costs making vitrification cost effective on a life cycle basis.
Date: May 1, 1996
Creator: Jantzen, C.M.; Whitehouse, J.C.; Smith, M.E.; Ramsey, W.G. & Pickett, J.B.
Partner: UNT Libraries Government Documents Department

A transmission electron microscopy evaluation of solid-state upset welds in Type 304L stainless steel

Description: Transmission electron microscopy (TEM) was used to characterize the microstructures at and near the weld interface in upset welded Type 304L stainless steel test samples. Two sample configurations were examined in this study; upset welded cylinders prepared using a commercial resistance welder and cylindrical shaped samples welded in a Gleeble 1500 thermomechanical simulation device. The Gleeble samples evaluated were welded at 800 C, 900 C and 1,200 C with a 0.5 cm weld upset. The base microstructure of the samples varied with weld temperature. The lower temperature specimens contained a large free-dislocation density and distinct dislocation cells. The higher temperature specimens contained well-developed subgrains and a much lower free-dislocation density. The microstructure of the upset welded samples most closely resembled the 1,200 C Gleeble sample. No distinct bond line was observed by TEM in any of the specimens, i.e., diffusion and grain growth occurred across all weld interfaces. However, weld interfaces in both specimen configurations were characterized by the presence of 50--300 nm diameter particles spaced between 300 and 1,300 nm apart. Through the use of electron diffraction analysis and X-ray microanalysis two precipitate types were identified in both specimen configurations. A crystalline phase very similar to Mn{sub 1.5}Cr{sub 1.5}O{sub 4} and an amorphous phase enriched mainly in Si and Al were observed. Surface oxides and/or internal impurities may be sources for these precipitates. Future work will include a controlled study designed to determine the origin of the interface precipitates.
Date: September 8, 1995
Creator: Tosten, M.H.
Partner: UNT Libraries Government Documents Department

Vitrification of cesium-contaminated organic ion exchange resin

Description: Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.
Date: August 1, 1994
Creator: Sargent, T. N., Jr.
Partner: UNT Libraries Government Documents Department

Effects of periodic manual stirring and uranium addition on surrogate plutonium glass processing

Description: Using thorium as a plutonium surrogate, homogeneous glasses have been processed ranging from 15 to 20 elemental weight percent thorium with 0 to 5 elemental weight percent uranium. Homogeneous glasses have been processed at 1,475 C with residence times ranging from 1 to 12 hours. High ramp rates successfully inhibited thorium silicate formation. Residence times of 5 to 7 hours were required for static melts to become homogeneous for glasses containing 15 elemental weight percent thorium. Thorium dissolution rates have been determined for glasses containing 15 elemental weight percent thorium with and without the addition of uranium. When compared to identical glass compositions which were not stirred, stirred melts produced homogeneous vitreous products with an 80 percent reduction in residence time. A 20 elemental weight percent thorium glass was produced at 1,475 C by adding 2 elemental weight percent uranium. Without the addition of uranium, a melt temperature of 1,500 C was required.
Date: September 13, 1996
Creator: Meaker, T.F.
Partner: UNT Libraries Government Documents Department

Glass composition development for stabilization of lead based paints

Description: Exposure to lead can lead to adverse health affects including permanent damage to the central nervous system. Common means of exposure to lead are from ingestion of lead paint chips or breathing of dust from deteriorating painted surfaces. The U.S. Army has over 101 million square feet of buildings dating to World War II or earlier. Many of these structures were built before the 1978 ban on lead based paints. The U.S. Army Corps of Engineers CERL is developing technologies to remove and stabilize lead containing organic coatings. Promising results have been achieved using a patented flame spray process that utilizes a glass frit to stabilize the hazardous constituents. When the glass frit is sprayed onto the paint containing substrate, differences in thermal expansion coefficients between the frit and the paint results in spalling of the paint from the substrate surface. The removed fragments are then collected and remelted to stabilize the hazardous constituents and allow for disposal as non-hazardous waste. Similar successful results using a patented process involving microwave technology for paint removal have also been achieved. In this process, the painted surface is coated with a microwave coupling compound that when exposed to microwave energy results in the spalling of the hazardous paint from the surface. The fragments can again be accumulated and remelted for stabilization and disposal.
Date: October 1, 1996
Creator: Marra, J.C.
Partner: UNT Libraries Government Documents Department

Distribution of radionuclides in L-Lake surface sediments phase 3

Description: Gamma-emitting radionuclides in L Lake were examined in situ with an underwater High Purity Germanium (HPGe) detector and further studied by retrieving various sediment samples for analysis by HPGe gamma spectrometry. The predominant man-made radionuclide detected was cesium-137. These measurements constituted Phase 3 of a four phase strategy for characterizing L-Lake contaminants. The data provided by these studies will be utilized in the preparation of an Environmental Impact Statement that evaluates the consequences of discontinuing river water pumping to the man-made cooling water reservoirs on the Savannah River Site. A site evaluation report will also be prepared for the L-Lake basin.
Date: August 1, 1996
Creator: Dunn, D.L.
Partner: UNT Libraries Government Documents Department

Am/Cm target glass durability dependence on pH (U). Revision 1

Description: At the Westinghouse Savannah River Company near Aiken, South Carolina, a process is being developed to safely vitrify all of the highly radioactive americium/curium (Am/Cm) material and a portion of the other fissile actinide materials stored on site. One goal of this campaign is to provide Oak Ridge National Laboratory with the excess Am/Cm so it can be recycled as opposed to simply disposing of it as waste. The vitrification will allow safe transportation of the Am/Cm to Oak Ridge as well as safe storage once it arrives. The Am/Cm Target glass being used in this project has been specifically designed to be extremely durable in aqueous environments while it can be selectively attacked by nitric acid to recover the valuable Am and Cm isotopes. Similar glass compositions could be used for storage and retrieval of other actinides on the WSRC site. Previous reports have presented the time, temperature, and compositional dependence of the Am/Cm glass durability. This paper will show results from a pH study on the Am/Cm Target glass durability. The data indicate that the Am/Cm Target Glass durability decreases as pH decreases from a neutral reading. These findings support the extraction of the valuable isotopes from the glass using nitric acid.
Date: March 1, 1996
Creator: Daniel, W.E. & Best, D.R.
Partner: UNT Libraries Government Documents Department

Use of a 2-inch, dual screen well to conduct aquifer tests in the upper and lower Lost lake aquifer zones: Western sector, A/M area, SRS

Description: The Western Sector, A/M Area is located just west of the M-Area Settling Basin on an upland area. The area is adjacent to the gently inclined area where the upland drops off to the Savannah River floodplain. Water in the parts of the uppermost aquifers contains dissolved contaminants which originated at the land surface and have leached downward into the groundwater. Subsurface contamination originated in the locality of the M-Area Settling Basin and Lost Lake, which is a Carolina Bay. These locations functioned as disposal sites for industrial solvents during the early years of operation of the Savannah River Site. The primary groundwater contaminants are trichloroethylene (TCE) and tetrachloroethylene (PCE), and groundwater concentrations of TCE are significantly greater than the PCE.
Date: September 1, 1996
Creator: Hiergesell, R.A. & Novick, J.S.
Partner: UNT Libraries Government Documents Department

Vitrification of Three Low-Activity Radioactive Waste Streams from Hanford

Description: As part of a demonstration for British Nuclear Fuels Limited, Incorporated (BNFL), the Immobilization Technology Section (ITS) of the Savannah River Technology Center (SRTC) has produced and characterized three low-activity waste (LAW) glasses from Hanford radioactive waste samples. The three LAW glasses were produced from radioactive supernate samples that had been treated by the Waste Processing Technology Section (WPTS) at SRTC to remove most of the radionuclides. These three glasses were produced by mixing the waste streams with between four and nine glass-forming chemicals in platinum/gold crucibles and heating the mixture to between 1120 and 1150 degrees C. Compositions of the resulting glass waste forms were close to the target compositions. Low concentrations of radionuclides in the LAW feed streams and, therefore, in the glass waste forms supported WPTS conclusions that pretreatment had been successful. No crystals were detected in the LAW glasses. In addition, all glass waste forms passed the leach tests that were performed. These included a 20 degrees C Product Consistency Test (PCT) and a modified version of the United States Environmental Protection Agency Toxicity Characteristic Leaching Procedure (TCLP).
Date: September 1, 1998
Creator: Ferrara, D.M.; Crawford, C.L.; Ha, B.C. & Bibler, N.E.
Partner: UNT Libraries Government Documents Department

Application of a three-dimensional prognostic model during the ETEX real-time modeling exercise: Evaluation of results

Description: Increases in computing capabilities and ready access to large-scale model output make it possible to employ advanced three-dimensional prognostic models to forecast the long-range transport of toxic or radioactive gases for emergency response. The Savannah River Technology Center (SRTC) of the U.S. Department of Energy`s Savannah River Site demonstrated this during the European Tracer EXperiment (ETEX). ETEX, conducted in the Fall of 1994, provided an opportunity to evaluate the performance of models for long-range atmospheric pollutant transport and dispersion. A comparison of SRTC forecast results for the first ETEX experiment with measured surface tracer gas concentrations shows that the predicted plume is transported too quickly and surface concentrations are low. However, modeling studies show that the forecast performance is significantly improved if convective parameterization is not employed.
Date: May 1, 1997
Creator: Griggs, D.P.
Partner: UNT Libraries Government Documents Department

Design, operation, and evaluation of the transportable vitrification system

Description: The Transportable Vitrification System (TVS) is a transportable melter system designed to demonstrate the treatment of low-level and mixed hazardous and radioactive wastes such as wastewater treatment sludges, contaminated soils and incinerator ash. The TVS is a large-scale, fully integrated vitrification system consisting of melter feed preparation, melter, offgas, service, and control modules. The TVS was tested with surrogate waste at the Clemson University Environmental Systems Engineering Department`s (ESED) DOE/Industry Center for Vitrification Research prior to being shipped to the DOE Oak Ridge Reservation (ORR) K-25 site for treatment of mixed waste. This testing, along with additional testing at ORR, proved that the TVS would be able to successfully treat mixed waste. These surrogate tests consistently produced glass that met the EPA Toxicity Characteristic Leaching Procedure (TCLP). Performance of the system resulted in acceptable emissions of regulated metals from the offgas system. The TVS is scheduled to begin mixed waste operations at ORR in June 1997.
Date: February 20, 1997
Creator: Zamecnik, J.R.; Young, S.R.; Hansen, E.K. & Whitehouse, J.C.
Partner: UNT Libraries Government Documents Department

Validation of DWPF MOG dynamics model -- Phase 1

Description: The report documents the results of a study to validate the DWPF melter off-gas system dynamics model using the data collected during the Waste Qualification Runs in 1995. The study consisted of: (1) calibration of the model using one set of melter idling data, (2) validation of the calibrated model using three sets of steady feeding and one set of transient data, and (3) application of the validated model to simulate the melter overfeeding incident which took place on 7/5.95. All the controller tuning constants and control logic used in the validated model are identical to those used in the DCS in 1995. However, the model does not reflect any design and/or operational changes made in 1996 to alleviate the glass pouring problem. Based on the results of the overfeeding simulation, it is concluded that the actual feed rates during that incident were about 2.75 times the indicated readings and that the peak concentration of combustible gases remained below 15% of the lower flammable limit during the entire one-hour duration.
Date: September 23, 1996
Creator: Choi, A.S.
Partner: UNT Libraries Government Documents Department

DWPF integrated cold runs revised technical bases for precipitate hydrolysis

Description: The report defines new precipitate hydrolysis process operating parameters for DWPF Chemical runs assuming the precipitate feed simulants to be processed reflect the decision to implement a final wash of the tetraphenylborate slurry before transfer to DWPF (i.e. the Late Wash Facility). Control of the nitrite content of the tetraphenylborate slurry to 0.01M or less has eliminated the need for hydroxylamine nitrate (HAN) during hydrolysis. Consequently, the oxidant nitrous oxide will not be generated. However, nitric oxide (NO) is expected to be generated (reaction of formic acid with nitrite) and some fraction of the NO can be expected to be oxidized to nitrogen dioxide. The rate of NO generation with low nitrite feed has not been quantified at this time nor is the extent to which the NO is oxidized to NO{sub 2} known. A mass spectrometer is being installed in the Precipitate Hydrolysis Experimental Facility (PHEF) which will enable the NO generation rate to be defined as well as the extent to which the NO is oxidized to NO{sub 2}. There is some undocumented data available for C{sub 6}H{sub 6}/NO and C{sub 6}H{sub 6}/NO{sub 2} with N{sub 2} as the diluent but no similar data for CO{sub 2}. Development of test data in the required time frame is not possible. However, MOC`s will be estimated for benzene/NO/NO{sub 2}/CO{sub 2} gas mixtures (the MOC is expected to be approximately 60% less than for the HAN process). Once these data are obtained, and NO/NO{sub 2} concentration profiles are obtained from PHEF hydrolysis process demonstrations, a flammability control strategy for the DWPF Salt Processing Cell will be developed. Implementation of the HAN process purge strategy upon startup of the SPC with the late wash process would be conservative.
Date: June 1, 1992
Creator: Landon, L.F.
Partner: UNT Libraries Government Documents Department

Local Area Network Material Accounting System (LANMAS) Functions and Features Overview

Description: The Local Area Network Material Accounting System (LANMAS) application is a standardized approach to comply with the DOE Order 5633.3B, control and Accountability of Nuclear Material, material accounting requirements. This paper provides a general overview of the functions and features included in the LANMAS application.
Date: July 1, 1998
Creator: Robichaux, J.J.
Partner: UNT Libraries Government Documents Department

Maximum total organic carbon limit for DWPF melter feed

Description: DWPF recently decided to control the potential flammability of melter off-gas by limiting the total carbon content in the melter feed and maintaining adequate conditions for combustion in the melter plenum. With this new strategy, all the LFL analyzers and associated interlocks and alarms were removed from both the primary and backup melter off-gas systems. Subsequently, D. Iverson of DWPF- T{ampersand}E requested that SRTC determine the maximum allowable total organic carbon (TOC) content in the melter feed which can be implemented as part of the Process Requirements for melter feed preparation (PR-S04). The maximum TOC limit thus determined in this study was about 24,000 ppm on an aqueous slurry basis. At the TOC levels below this, the peak concentration of combustible components in the quenched off-gas will not exceed 60 percent of the LFL during off-gas surges of magnitudes up to three times nominal, provided that the melter plenum temperature and the air purge rate to the BUFC are monitored and controlled above 650 degrees C and 220 lb/hr, respectively. Appropriate interlocks should discontinue the feeding when one or both of these conditions are not met. Both the magnitude and duration of an off-gas surge have a major impact on the maximum TOC limit, since they directly affect the melter plenum temperature and combustion. Although the data obtained during recent DWPF melter startup tests showed that the peak magnitude of a surge can be greater than three times nominal, the observed duration was considerably shorter, on the order of several seconds. The long surge duration assumed in this study has a greater impact on the plenum temperature than the peak magnitude, thus making the maximum TOC estimate conservative. Two models were used to make the necessary calculations to determine the TOC limit.
Date: March 13, 1995
Creator: Choi, A.S.
Partner: UNT Libraries Government Documents Department

Rheology enhancement for remediated PX6 melter feed

Description: This document is referenced in WSRC-TR-94-0556. This memorandum summarizes results of experimental work performed on the original IDMS PX6 melter feed, the remediated IDMS PX6 melter feed, and melter feeds produced in a laboratory simulation to duplicate the IDMS remediation as well as the experimental results on the caustic treatment to enhance the rheology. Characterization of the products of excess caustic addition and what steps to take if excess caustic is inadvertently added to the IDMS PX6 melter feed are also discussed
Date: August 23, 1996
Creator: Marek, J.C. & Eibling, R.E.
Partner: UNT Libraries Government Documents Department

Backup power working group best practices handbook for maintenance and operation of engine generators, Volume 1. Revision 1

Description: This handbook is divided into the four chapters. Chapter one covers the design, procurement, storage, handling and testing of diesel fuel oil to be used in DOE backup power supplies. Chapter two discusses the selection of automatic transfer switches to be used in DOE backup power supplies. Chapter three is about low voltage open frame air circuit breaker operation, testing, and maintenance for DOE backup power supplies. And chapter four covers installation, design, and maintenance of engine cooling water and jacket water systems.
Date: June 1, 1997
Creator: Gross, R.; Padgett, A.B.; Burrows, K.P.; Fairchild, P.N.; Lam, T. & Janes, J.
Partner: UNT Libraries Government Documents Department

Development of total uranium analytical method by L x-ray fluorescence

Description: This paper describes development of an L x-ray fluorescence technique to perform total uranium analysis using an internal excitation source which is added directly to the sample. The method has been demonstrated with synthetic U samples in the limited concentration range of 1g/l to 15g/l, and provides the advantages of simplicity, involving no mechanical parts which would normally be found in an external excitation source. Total uranium is determined by counting L x-rays fluoresced by a microCurie level spike of Cd-109 added directly to the sample and without shielding the excitation source from the detector. A method for correction of sample self-absorption is included in the analysis.
Date: September 18, 1996
Creator: Dewberry, R.A.
Partner: UNT Libraries Government Documents Department

Rugged fiber optic probes and sampling systems for remote chemical analysis via the Raman technique

Description: Recent advances in fiber optics, diode lasers, CCD detectors, dielectric and holographic optical filters, grating spectrometers, and chemometric data analysis have greatly simplified Raman spectroscopy. In order to make a rugged fiber optic Raman probe for solids/slurries like these at Savannah River, we have designed a probe that eliminates as many optical elements and surfaces as possible. The diffuse reflectance probe tip is modified for Raman scattering by installing thin dielectric in-line filters. Effects of each filter are shown for the NaNO{sub 3} Raman spectrum. By using a diode laser excitation at 780 nm, fluorescence is greatly reduced, and excellent spectra may be obtained from organic solids. At SRS, fiber optic Raman probes are being developed for in situ chemical mapping of radioactive waste storage tanks. Radiation darkening of silica fiber optics is negligible beyond 700 nm. Corrosion resistance is being evaluated. Analysis of process gas (off-gas from SRS processes) is investigated in some detail: hydrogen in nitrogen with NO{sub 2} interference. Other applications and the advantages of the method are pointed out briefly.
Date: July 1, 1996
Creator: Nave, S.E.
Partner: UNT Libraries Government Documents Department

Parametric Thermal Analysis for Codisposal Waste Package Canister

Description: The engineering viability of disposal of aluminum-clad, aluminum-based spent nuclear fuel (Al-SNF) in a geologic repository requires a thermal analysis to provide the temperature history of the waste form. Calculated temperatures are used to demonstrate compliance with criteria for waste acceptance into the Mined Geologic Disposal System and as input to assess the chemical and physical behavior of the waste form within the waste package (WP).A thermal analysis methodology was developed to calculate peak temperatures and temperature profiles of Al-SNF in the DOE spent nuclear fuel canister within a codisposal WP. A two-dimensional baseline model with conduction and radiation coupled heat transport was developed to evaluate the thermal performance of Al-SNF directly stored in a canister in a codisposal WP over the range of possible heat loads and boundary conditions. In addition, a conduction model and a detailed model which includes convection were developed to identify the dominant cooling mechanism under the present WP configuration, to investigate physical cooling mechanism in detail, and to estimate the conservatism imbedded in the baseline model.The results of the baseline model showed that the direct disposal configuration with a helium-filled WP satisfied the present waste acceptance criteria (WAC) for the WP design in terms of the peak temperature criterion, Tmax {lt} 350 degrees C, under the reference boundary conditions. A period of 10 years` cooling time for the decay heat loads of the SNF and the High-level Waste Glass Log (HWGL) regions was used as one of the reference design conditions.
Date: September 1, 1998
Creator: Lee, S.Y. & Sindelar, R.L.
Partner: UNT Libraries Government Documents Department

Structural analysis of closure cap barriers: A pre-test study for the Bentonite Mat Demonstration Project

Description: According to the EPA-recommended closure cap design a waste site can either be covered with a single layer cap made of 36 inches of compacted soil (clay) or with a multilayer cap consisting of an upper vegetative layer underlain by a drainage layer over a low permeability layer. The Bentonite Mat Demonstration Project (BMDP) is a field demonstration study to determine the construction/installation requirements, permeability, and subsidence performance characteristics of a composite barrier. The composite barrier will consist of on-site sandy-clay blanketed by a bentonite mat and a flexible High Density Polyethylene (HDPE) liner (also called flexible membrane liner). Construction of one control test pad and three bentonite test pads are planned. The control test pad will be used to establish baseline data. Underneath the composite clay cap is a four-foot loose sand layer in which cavities will be created by evacuation of sand. The present work provides a mathematical model for the BMDP. The mathematical model will be used to simulate the mechanical and structural responses of the composite clay cap during the testing processes. Based upon engineering experience and technical references, a set of nominal soil parameters have been selected. Currently, detailed soil test data and cavity configuration data are not available to validate the mathematical model. Since the configuration of the cavities created in the testing process is irregular and unpredictable, two extreme configurations are considered in this mathematical model, viz., the circular cavity and the infinitely long trench in the sand underneath the cap. This approach will provide bounds for the testing results.
Date: October 1, 1993
Creator: Gong, Chung
Partner: UNT Libraries Government Documents Department