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Thermal conductivity of $sup 238$PuO$sub 2$ powder, intermediates, and dense fuel forms

Description: The thermal conductivities of porous $sup 238$PuO$sub 2$ powder (calcined oxalate), milled powder, and high-density granules were calculated from direct measurements of steady-state temperature profiles resulting from self- heating. Thermal conductivities varied with density, temperature, and gas content of the pores. Errors caused by thermocouple heat conduction were less than 5 percent when the dimensions of the thermal conductivity cell and the thermocouple were properly selected. (auth)
Date: October 1, 1975
Creator: Bickford, D.F. & Crain, B. Jr.
Partner: UNT Libraries Government Documents Department

Numerical Models of Waste Glass Models Part II Computational Modeling of DWPF

Description: Computational fluid-dynamics numerical models are developed for joule-heated slurry fed waste glass melters, such as the Defense Waste Processing Facility Melter. An important feature of the analyses is the simulation of the cold cap region with its thermally resistant foamy layer. Using a simplified model which describes the foam void fraction as a function of temperature, based on laboratory sample testing, characteristic features of the cold cap are simulated. Two- and three-dimensional models are presented.
Date: April 23, 2003
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

DWPF Melter Air-Lift Bubbler: Development and Testing for Increasing Glass Melt Rates and Waste Dissolution

Description: A DOE Tank Focus Area program to assess possible means of increasing Defense Waste Processing Facility Melter melt rate was initiated in FY01. A lumped parameter comparison of DWPF data with earlier pilot scale data indicated that melter capacity for a given feed was limited by overheating of the glass immediately under the reacting feed.
Date: December 13, 2002
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Vitrification of organics-containing wastes

Description: A process for stabilizing organics-containing waste materials and recovery metals therefrom, and a waste glass product made according to the process are described. Vitrification of wastes such as organic ion exchange resins, electronic components and the like can be accomplished by mixing at least one transition metal oxide with the wastes, and, if needed, glass formers to compensate for a shortage of silicates or other glass formers in the wastes. The transition metal oxide increases the rate of oxidation of organic materials in the wastes to improve the composition of the glass-forming mixture: at low temperatures, the oxide catalyzes oxidation of a portion of the organics in the waste; at higher temperatures, the oxide dissolves and the resulting oxygen ions oxidize more of the organics; and at vitrification temperatures, the metal ions conduct oxygen into the melt to oxidize the remaining organics. In addition, the transition metal oxide buffers the redox potential of the glass melt so that metals such as Au, Pt, Ag, and Cu separate form the melt in the metallic state and can be recovered. After the metals are recovered, the remainder of the melt is allowed to cool and may subsequently be disposed of. The product has good leaching resistance and can be disposed of in an ordinary landfill, or, alternatively, used as a filler in materials such as concrete, asphalt, brick and tile.
Date: January 1, 1995
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

TTP SR1-6-WT-31, Milestone C.3-2 annual report on Clemson/INEEL melter work. Revision 1

Description: This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.
Date: December 17, 1999
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Foreign Travel Report - West Germany and Belgium - September 9 - September 13, 1985

Description: This report discusses visitation of the PAMELA plant which provided an opportunity to observe the operation and design of this European waste solidification facility. The aim of the workshop was to exchange expertise relative to the safe vitrification of HLLW in order to determine which areas were technologically solved and which areas required further study.
Date: May 17, 2001
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Material Selection for Defense Waste Processing Facility

Description: Construction has started on a facility to immobilize high-level radioactive waste in borosilicate glass at the Department of Energy's Savannah River Plant. Type 304L stainless steel is generally sufficient for supply tankage and service lines. It is used as the reference material in chemical reprocessing of reactor target and fuel tubes. Type 304L, however, has unacceptable stress corrosion cracking resistance in solutions containing formic acid and chloride. Scouting tests were performed on twelve commercial nickel-based alloys in simulated process solutions containing halides, sulfates, nitrates, mercury and formic acid. Mercuric ions and halides interact in acidic environments to increase pitting and crevice attack. Alloys with combined chromium plus molybdenum contents greater than 30 percent, that also contain greater than 9 percent molybdenum, were most resistant to pitting and crevice corrosion. Based on this testing, Alloy C-276 has been selected as the reference process equipment material, with Inconel 690 and ALLCORR selected for specialty areas.
Date: July 17, 1985
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

TTP SR1-6-WT-31, Milestone C.3-2 Annual Report on Clemson/INEEL Melter Work

Description: This work is performed in collaboration with RL37WT31-C and ID77WT31-B. During the first two years of radioactive operation of the DWPF process, several areas for improvement in melter design have been identified. The continuing scope of this task is to address performance limitations and deficiencies identified by the user. SRS will design and test several configurations of the melter pour spout and associated equipment to improve consistency of performance and recommend design improvements.
Date: October 20, 1999
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

TTP SR1-6-WT-31, Milestone XXX, Milestone C.1-2 Report: Functional Test of Pour Spout Insert and Knife Edge

Description: During the first two years of radioactive operation of the Defense Waste Processing Facility process, several areas for improvement in melter design were identified. Due to the need for a process that allows continuous melter operation, the down time associated with disruption to melter operation and pouring has significant cost impact. A major objective of this task is to address performance limitations and deficiencies identified by the user.
Date: July 29, 1999
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Numerical Models of Waste Glass Models Part I Lumped Parameter Modeling of DWPF

Description: Defense Waste Processing Facility melter production data from three waste batches were analyzed using a lumped parameter approach which separates effects of melter feed, heater temperature, and power on melt rate under various modes of operation. A detailed distribution of power inputs and heat consumption pathways, as provided by the lumped parameter model, evaluated possible causes of melt rate reduction and other operational data. Theoretical aspects of the steady state analysis, as well as transient analysis, are presented.The lumped model complements the more detailed multi-dimensional computational models by providing boundary conditions for such models, and is the only practical way of predicting transients.
Date: April 23, 2003
Creator: Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Devitrification behavior of SRL defense waste glass

Description: Simulated SRL waste was prepared with compositions varying in iron and aluminum content. Two batches with similar composition were produced with different amounts of reducing agent added. Samples were isothermally heat treated and used to derive time-temperature-transformation diagrams. Supplementary samples were cooled in a manner programmed to simulate the cooling curves of production canisters. Less than 10% total devitrification occurs during normal processing. However, when waste glass 165 was purposely devitrified, up to 30 volume percent total spinel and acmite formed. Formation of these species had minor effect on leachability in MCC-1 and accelerated leach tests. 20 references, 4 figures, 2 tables.
Date: November 1, 1983
Creator: Bickford, D F & Jantzen, C M
Partner: UNT Libraries Government Documents Department

High temperature materials for radioactive waste incineration and vitrification. Revision 1

Description: Incineration or vitrification of radioactive waste subjects equipment to alkaline or acidic fluxing, oxidation, sulfidation, carburization, and thermal shock. It is necessary to select appropriate materials of construction and control operating conditions to avoid rapid equipment failure. Nickel- and cobalt-based alloys with high chromium or aluminum content and aluminum oxide/chromium oxide refractories with high chromium oxide content have provided the best service in pilot-scale melter tests. Inconel 690 and Monofrax K-3 are being used for waste vitrification. Haynes 188 and high alumina refractory are undergoing pilot scale tests for incineration equipment. Laboratory tests indicate that alloys and refractories containing still higher concentrations of chromium or chromium oxide, such as Inconel 671 and Monofrax E, may provide superior resistance to attack in glass melter environments.
Date: January 1, 1986
Creator: Bickford, D F; Ondrejcin, R S & Salley, L
Partner: UNT Libraries Government Documents Department

Redox control of electric melters with complex feed compositions. Part I: analytical methods and models

Description: The redox state of glass from electric melters with complex feed compositions is determined by balance between gases above the melt, and transition metals and organic compounds in the feed. Part I discusses experimental and computational methods of relating flowrates and other melter operating conditions to the redox state of glass, and composition of the melter offgas. Computerized thermodynamic computational methods are useful in predicting the sequence and products of redox reactions and in assessing individual process variations. Melter redox state can be predicted by combining monitoring of melter operating conditions, redox measurement of fused melter feed samples, and periodic redox measurement of product. Mossbauer spectroscopy, and other methods which measure Fe(II)/Fe(III) in glass, can be used to measure melter redox state. Part II develops preliminary operating limits for the vitrification of High-Level Radioactive Waste. Limits on reducing potential to preclude the accumulation of combustible gases, accumulation of sulfides and selenides, and degradation of melter components are the most critical. Problems associated with excessively oxidizing conditions, such as glass foaming and potential ruthenium volatility, are controlled when sufficient formic acid is added to adjust melter feed rheology.
Date: January 1, 1985
Creator: Bickford, D F & Diemer, Jr, R B
Partner: UNT Libraries Government Documents Department

Fabrication of granule and pellet heat sources from oxalate-based $sup 238$PuO$sub 2$

Description: Suitable fuel forms for radioisotopic thermoelectric generators are granules of high internal density (greater than 95 percent of theoretical) or geometric shapes (80 to 90 percent dense) such as pellets or spheres. Both forms can be made from calcined $sup 238$Pu(III) oxalate. The conditions for processing PuO$sub 2$ are controlled during fuel form fabrication to ensure pellet integrity; to control density, grain size, and porosity distribution; and to minimize the fraction of potentially respirable fines. The competing phenomena of expansion caused by radiation damage (including helium generation from radioactive decay of plutonium) and shrinkage caused by sintering must be controlled to assure dimensional stability. The variation of microstructure and related physical properties with process parameters is discussed. (auth)
Date: January 1, 1975
Creator: Bickford, D.F. & Rankin, D.T.
Partner: UNT Libraries Government Documents Department

The Behavior and Effects of the Noble Metals in the DWPF Melter System

Description: Governments worldwide have committed to stabilization of high-level nuclear waste (HLW) by vitrification to a durable glass form for permanent disposal. All of these nuclear wastes contain the fission-product noble metals: ruthenium, rhodium, and palladium. SRS wastes also contain natural silver from iodine scrubbers. Closely associated with the noble metals are the fission products selenium and tellurium which are chemical analogs of sulfur and which combine with noble metals to influence their behavior and properties. Experience has shown that these melt insoluble metals and their compounds tend to settle to the floor of Joule-heated ceramic melters. In fact, almost all of the major research and production facilities have experienced some operational problem which can be associated with the presence of dense accumulations of these relatively conductive metals and/or their compounds. In most cases, these deposits have led to a loss of production capability, in some cases, to the point that melter operation could not continue. HLW nuclear waste vitrification facilities in the United States are the Department of Energy`s Defense Waste Processing Facility (DWPF) at the Savannah River Site, the planned Hanford Waste Vitrification Plant (HWVP) at the Hanford Site and the operating West Valley Demonstration Project (WVDP) at West Valley, NY. The Integrated DWPF Melter System (IDMS) is a vitrification test facility at the Savannah River Technology Center (SRTC). It was designed and constructed to provide an engineering-scale representation of the DWPF melter and its associated feed preparation and off-gas treatment systems. An extensive noble metals testing program was begun in 1990. The objectives of this task were to explore the effects of the noble metals on the DWPF melter feed preparation and waste vitrification processes. This report focuses on the vitrification portion of the test program.
Date: November 30, 1997
Creator: Smith, M. E. & Bickford, D. F.
Partner: UNT Libraries Government Documents Department

Bench-scale vitrification studies with Savannah River Site mercury contaminated soil

Description: The Savannah River Technology Center (SRTC) has been charted by the Department of Energy (DOE)--Office of Technology Development (OTD) to investigate vitrification technology for the treatment of Low Level Mixed Wastes (LLMW). In fiscal year 1995, mercury containing LLMW streams were targeted. In order to successfully apply vitrification technology to mercury containing LLMW, the types and quantities of glass forming additives necessary for producing homogeneous glasses from the wastes have to be determined and the treatment for the mercury portion must also be determined. Selected additives should ensure that a durable and leach resistant waste form is produced, while the mercury treatment should ensure that hazardous amounts of mercury are not released into the environment. The mercury containing LLMW selected for vitrification studies at the SRTC was mercury contaminated soil from the TNX pilot-plant facility at the Savannah River Site (SRS). Samples of this soil were obtained so bench-scale vitrification studies could be performed at the SRTC to determine the optimum waste loading obtainable in the glass product without sacrificing durability and leach resistance. Vitrifying this waste stream also required offgas treatment for the capture of the vaporized mercury.
Date: December 1995
Creator: Cicero, C. A. & Bickford, D. F.
Partner: UNT Libraries Government Documents Department

Control of radioactive waste-glass melters: Part 3, Glass electrical stability

Description: Pilot waste-glass melter operations have indicated a tendency for noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Changes in melter geometry are being considered in Japan, Germany, and the United States to permit draining of the noble metals to reduce their effects. Physical modeling of melter electrical patterns, electrode/waste-glass electrochemistry, and non-linear electrical behavior have been evaluated for typical waste-glass. Major melter design changes should not be necessary for the US Department of Energy's Defense Waste Processing Facility (DWPF). Top electrodes will not be significantly affected. Minor alterations in melter design, monitoring of electrical characteristics, and adjustment of bottom electrode currents can provide protection from shorting if noble metals accumulate. 31 refs., 4 figs., 4 tabs.
Date: January 1, 1988
Creator: Bickford, D F; Propst, R C & Plodinec, M J
Partner: UNT Libraries Government Documents Department

DWPF (Defense Waste Processing Facility) glass composition control based on glass properties

Description: The Defense Waste Processing Facility (DWPF) will immobilize Savannah River Plant (SRP) High Level Waste as a durable borosilicate glass for permanent disposal in a civilian repository. The DWPF will be controlled based on glass composition. The waste glass physical and chemical properties, such as viscosity, liquidus temperature, and durability are functions of glass chemistry. Preliminary models have been developed to evaluate the effects of feed composition variability on the glass properties. These properties are presently being related to the waste glass composition in order to develop process control paradigms that include batching algorithms, hold points, and transfer limits. 3 refs., 6 tabs.
Date: January 1, 1988
Creator: Carter, J T; Brown, K G & Bickford, D F
Partner: UNT Libraries Government Documents Department

Control of high-level radioactive waste-glass melters

Description: The Defense Waste Processing Facility (DWPF) will immobilize Savannah River Site High Level Waste as a durable borosilicate glass for permanent disposal in a repository. The DWPF will be controlled based on glass composition. The following discussion is a preliminary analysis of the capability of the laboratory methods that can be used to control the glass composition, and the relationships between glass durability and glass properties important to glass melting. The glass durability and processing properties will be controlled by controlling the chemical composition of the glass. The glass composition will be controlled by control of the melter feed transferred from the Slurry Mix Evaporator (SME) to the Melter Feed Tank (MFT). During cold runs, tests will be conducted to demonstrate the chemical equivalence of glass sampled from the pour stream and glass removed from cooled canisters. In similar tests, the compositions of glass produced from slurries sampled from the SME and MFT will be compared to final product glass to determine the statistical relationships between melter feed and glass product. The total error is the combination of those associated with homogeneity in the SME or MFT, sampling, preparation of samples for analysis, instrument calibration, analysis, and the composition/property model. This study investigated the sensitivity of estimation of property data to the combination of variations from sampling through analysis. In this or a similar manner, the need for routine glass product sampling will be minimized, and glass product characteristics will be assured before the melter feed is committed to the melter.
Date: January 1, 1990
Creator: Bickford, D.F. & Coleman, C.J.
Partner: UNT Libraries Government Documents Department

Control of high level radioactive waste-glass melters

Description: Slurry Fed Melters (SFM) are being developed in the United States, Europe and Japan for the conversion of high-level radioactive waste to borosilicate glass for permanent disposal. The high transition metal, noble metal, nitrate, organic, and sulfate contents of these wastes lead to unique melter redox control requirements. Pilot waste-glass melter operations have indicated the possibility of nickel sulfide or noble-metal fission-product accumulation on melter floors, which can lead to distortion of electric heating patterns, and decrease melter life. Sulfide formation is prevented by control of the redox chemistry of the melter feed. The redox state of waste-glass melters is determined by balance between the reducing potential of organic compounds in the feed, and the oxidizing potential of gases above the melt, and nitrates and polyvalent elements in the waste. Semiquantitative models predicting limitations of organic content have been developed based on crucible testing. Computerized thermodynamic computations are being developed to predict the sequence and products of redox reactions and is assessing process variations. Continuous melter test results have been compared to improved computer staged-thermodynamic-models of redox behavior. Feed chemistry control to prevent sulfide and moderate noble metal accumulations are discussed. 17 refs., 3 figs.
Date: January 1, 1991
Creator: Bickford, D.F. & Choi, A.S.
Partner: UNT Libraries Government Documents Department

Test methods for selection of materials of construction for high-level radioactive waste vitrification. Revision

Description: Candidate materials of construction were evaluated for a facility at the Department of Energy's Savannah River Plant to vitrify high-level radioactive waste. Limited operating experience was available under the corrosive conditions of the complex vitrification process. The objective of the testing program was to provide a high degree of assurance that equipment will meet or exceed design lifetimes. To meet this objective in reasonable time and minimum cost, a program was designed consisting of a combination of coupon immersion and electrochemical laboratory tests and pilot-scale tests. Stainless steels and nickel-based alloys were tested. Alloys that were most resistant to general and local attack contained nickel, molybdenum (>9%), and chromium (where Cr + Mo > 30%). Alloy C-276 was selected as the reference material for process equipment. Stellite 6 was selected for abrasive service in the presence of formic acid. Alloy 690 and ALLCORR were selected for specific applications.
Date: January 1, 1986
Creator: Bickford, D F; Corbett, R A & Morrison, W S
Partner: UNT Libraries Government Documents Department

Redox control of electric melters with complex feed compositions. Part II: preliminary limits for radioactive waste melters

Description: Melter redox control is necessary for safe and continued melter operation. A combination of feed composition control, melter operational controls and monitors, and periodic determination of product glass redox state is sufficient to meet operating and safety requirements. Mossbauer spectroscopy, or other methods which determine the Fe(II)/Fe(III) ratio of the glass product, can be used to determine the oxidation state of the glass and thereby assess operating conditions. Slightly reducing conditions can eliminate radio-Ru volatility by suppressing the formation of RuO4. Reducing conditions also limit foaming resulting from the release of oxygen as transition metal oxides are dissolved in the melt. The calcination and partial combustion of organic compounds in the melter feed generates combustible mixtures of CO, H2 and benzene. The organics must be essentially completely incinerated to avoid the accumulation of combustible offgas mixtures, and prevent fouling of the equipment by soot and tars. Operation of the melter plenum above the autoignition temperature, metering in of purge air in excess of that required for complete combustion, and dilution by water vapor from reacted feed all preclude this occurrence in the melter. Prevention of dangerous offgas compositions after water vapor removal is assured by combustion in the melter, the addition of dilution air, and by continuous monitoring by % Lower Explosive Limit meters. Melter reducing power must be restricted to prevent formation of molten sulfides or selenides in the melter, and to prevent carburization and sulfidation attack of Inconel-690 melter components. Control of average oxygen partial pressure in the melter plenum is insufficient to assure prevention of localized attack of Inconel-690. An additional requirement is therefore necessary, that no soot or tarry substances be deposited on the Inconel-690.
Date: January 1, 1985
Creator: Bickford, D F; Diemer, Jr, R B & Iverson, D C
Partner: UNT Libraries Government Documents Department

Development of glass vitrification at SRL as a waste treatment technique for nuclear weapon components

Description: This report discusses the development of vitrification for the waste treatment of nuclear weapons components at the Savannah River Site. Preliminary testing of surrogate nuclear weapon electronic waste shows that glass vitrification is a viable, robust treatment method.
Date: January 1, 1991
Creator: Coleman, J.T. & Bickford, D.F.
Partner: UNT Libraries Government Documents Department

Fiscal year 1995 final report for TTP SR-1320-04

Description: The purpose of this Technical Task Plan (TTP) in fiscal year 1995 was to develop vitrification technology for application to mercury and organic waste streams, which are considered problem streams for a large portion of the DOE complexes. In addition, efforts were continued for pilot-scale demonstrations on Rocky Flats Plant (RFP) Precipitate sludge, and Los Alamos National Laboratory (LANL) TA-50 sludge, which was a carry-over of fiscal year 1994 activities. Crucible-scale studies were performed on mercury and organic waste streams to determine the optimum glass compositions. The optimal compositions were then used to treat actual wastes on a bench-top scale. Reports were written to summarize the data and results from the mercury and organic studies. The pilot-scale studies with RFP and LANL simulated sludge used glass compositions determined in fiscal year 1994 studies. The pilot-scale studies were attempted in the EnVitCo cold-top melter and the Stir-Melter{reg_sign} stirred melter at the DOE/Industrial Center for Vitrification Research (Center).
Date: September 30, 1995
Creator: Cicero, C.A.; Bickford, D.F. & Marra, J.C.
Partner: UNT Libraries Government Documents Department