UNT Libraries Government Documents Department - 433,315 Matching Results

Search Results

prev Results: 67051 - 67100 next
Leaching properties of solidified TRU waste forms
Safety analysis of waste forms requires an estimate of the ability of these forms to retain activity in the disposal environment. This program of leaching tests will determine the leaching properties of TRU contaminated incinerator ash waste forms using hydraulic cement, urea--formaldehyde, bitumen, and vinyl ester--styrene as solidification agents. Three types of leaching tests will be conducted, including both static and flow rate. Five generic groundwaters will be used. Equipment and procedures are described. Experiments have been conducted to determine plate out of /sup 239/Pu, counter efficiency, and stability of counting samples. (DLC)
Properties of radioactive wastes and waste containers. Progress report No. 5, April--June 1977
Portland type II cement decontamination factors for free standing water were determined to be 1, 11, and 200 for /sup 137/Cs, /sup 85/Sr, and /sup 60/Co respectively, indicating ion exchange processes occurring within the cement matrix. The quantity of organic carbon that could be removed from solidification agent matrix materials on leaching in distilled water was measured. No organic carbon was present in the portland type II cement leachant water after ten days while 3.4 ppM, 34.2 ppM, and 9500 ppM organic carbon were present respectively in the bitumen, Dow polymer and urea-formaldehyde leachant water (300 ml). The compression strengths of portland type II cement and urea-formaldehyde waste forms containing various simulated wastes were measured. The effect of the waste/cement ratio on the compression strength of portland type II cement simulated waste forms was also studied. The gamma radiation shielding characteristics of portland cement, urea-formaldehyde, and bitumen waste forms were studied in reference to the maximum incorporated activity permissible in 55 gallon waste packages for transportation in ''non-exclusive use'' vehicles under 49CFR173. Thermal conductivity, specific heat, and thermal diffusivity values were obtained for portland cement, urea-formaldehyde, bitumen, and Dow polymer waste forms. Solidification verification studies were initiated for the Dow polymer at waste/binder ratios representative of those proposed for use by the vendor. Successful solidifications were obtained for all waste types tested with the exception of 12 wt.% boric acid. The 12 wt.% boric acid waste was successfully solidified after a proprietary pretreatment of the waste stream.
Properties of radioactive wastes and waste containers. Quarterly progress report, January--March 1977
The densities of the simulated wastes used in this program were determined and factors reported to allow conversion of formulation data for urea-formaldehyde (UF) waste forms from weight ratios to volume ratios of waste to UF. Simulated Solka-Floc wastes were solidified with urea-formaldehyde but areas of unsolidified Solka-Floc were found in the final waste forms. The difficulty in mixing dewatered Solka-Floc waste with UF is presumed to be responsible. Attempts to solidify alkaline regenerative wastes with urea-formaldehyde were not successful. Increasing the waste/UF volume ratio to 3.0 produced acceptable solids with boric acid and decontamination waste, but not with chemical regenerative wastes. The use of masonry cement (one part Portland cement to one part anhydrous lime by weight) for the solidification of boric acid concentrate waste was investigated. Free standing solids were formed at waste/cement weight ratios of 0.6 and 1.0 but not at 1.5 or 2.0. Masonry cement was found to be superior to Portland cement for the solidification of boric acid wastes. The weight loss with temperature of urea-formaldehyde waste forms containing various simulated wastes was measured over the range of 25 to 500/sup 0/C. Weight losses due to the evaporation of water, decomposition of UF and decomposition of the wastes were observed. Static leaching experiments were conducted to determine the rate of release of cesium-137 and strontium-85 from urea-formaldehyde specimens and bead and powdered cation exchange resins. Results for the leaching of these materials in salt water, tap water, and distilled water are reported. Hydrostatic testing of modified DOT 17H open head 55 gallon drums was performed. These drums met the required DOT specifications and ultimately failed at an average pressure of 44 psig by separation of the drum head from the drum body at the gasket.
Properties of radioactive wastes and waste containers. Progress report No. 6, July--September 1977
A survey was made of the available literature on the corrosion of steels in soil environments. The effect of the physical and chemical properties of the soil on the rate and type of corrosion of steels has been evaluated. The corrosion rates of ferrous alloys are influenced primarily by the soil environment; alloy compositional and microstructural considerations are secondary. However, as the steel is made more resistant to uniform corrosion it becomes more susceptible to pitting corrosion. The various tests and criteria proposed to measure the corrosiveness of soil are reviewed. 7 tables, 9 figures, 17 references.
Tritium storage development. Progress report No. 8, April--June 1976
Lysimeter testing of polymer impregnated tritiated concrete (PITC) specimens at the Savannah River Laboratory (SRL) has continued. After twenty-three weeks, an average tritium fraction release rate of 3.37 x 10/sup -7/ day/sup -1/ has been determined in the percolate water with no measurable release to the air. Data from this experiment is extrapolated to estimate long-term tritium releases. A duplicate PITC specimen is in static leaching in distilled water. After seventy-two days, the average tritium fraction release rate has been 1.96 x 10/sup -5/ day/sup -1/. An estimation of the increased severity of static leaching in distilled water relative to lysimeter testing is made.
Waste form development program. Annual report, October 1982-September 1983
This report provides a summary of the work conducted for the Waste Form Development/Test Program at Brookhaven National Laboratory in FY 1983 under the sponsorship of the US Department of Energy's Low-Level Waste Management Program. The primary focus of this work is the investigation of new solidification agents which will provide improved immobilization of low-level radioactive wastes in an efficient, cost-effective manner. A working set of preliminary waste form evaluation criteria which could impact upon the movement of radionuclides in the disposal environment was developed. The selection of potential solidification agents for further investigation is described. Two thermoplastic materials, low-density polyethylene and a modified sulfur cement were chosen as primary candidates for further study. Three waste types were selected for solidification process development and waste form property evaluation studies which represent both new volume reduction wastes (dried evaporator concentrates and incinerator ash) and current problem wastes (ion exchange resins). Preliminary process development scoping studies were conducted to verify the compatibility of selected solidification agents and waste types and the potential for improved solidification. Waste loadings of 60 wt % Na/sub 2/SO/sub 4/, 25 wt % H/sub 3/BO/sub 3/, 25 wt % incinerator ash and 50 wt % dry ion exchange resin were achieved using low density polyethylene as a matrix material. Samples incorporating 65 wt % Na/sub 2/SO/sub 4/, 40 wt % H/sub 3/BO/sub 3/, 20 wt % incinerator ash and 40 wt % dry ion exchange resin were successfully solidified in modified sulfur cement. Additional improvements are expected for both matrix materials as process parameters are optimized. Several preliminary property evaluation studies were performed to provide the basis for an initial assessment of waste form acceptability. These included a two-week water immersion test and compressive load testing.
Fixation of aqueous tritiated waste in polymer impregnated concrete and in polyacetylene
Tritiated aqueous waste can be used to hydrate hydraulic cement producing a concrete that contains a network of interconnected porosity. Such a product is subject to water intrusion and subsequent tritium loss by leaching and exchange. Techniques have been developed to impregnate this porosity with styrene monomer which is then polymerized in situ, resulting in a concrete that is essentially impermeable while its strength, durability, and resistance to chemical attack are significantly improved. Tritium bulk leach rates as low as 1.68 x 10$sup -4$ g/(cm$sup 2$-day) have been measured for polymer-impregnated concrete in water. An adsorbent additive can be incorporated to increase the specific tritiated waste loading of the concrete. Depending upon the formulations, these composites incorporate 5.8 to 8.3 liters HTO per cubic foot. Tritiated aqueous waste can also be fixed in polymeric form as polyacetylene through reaction with calcium carbide to form tritiated acetylene which is subsequently polymerized. Acetylene polymerization is accomplished by either $sup 60$Co gamma irradiation or thermal catalysis over cupric oxide. The tritiated polyacetylene produced can contain up to 50 atomic percent tritium and is essentially non-leachable, insoluble, thermally stable to 325$sup 0$C, and chemically inert. The bulk leach rate of tritiated polyacetylene was determined to be of the order of 1.8 x 10$sup -8$ g/(cm$sup 2$-day). Radiolysis by $sup 60$Co gamma irradiation results in a G value for hydrogen production of 0.15 molecules/100 eV. Tritiated polyacetylene can be incorporated as an aggregate in concrete, polymer concrete, or polymer impregnated concrete to form a monolithic solid. (auth)
Assessment of microbial processes on radionuclide mobility in shallow land burial. [West Valley, NY; Beatty, Nevada; Maxey Flats, Kentucky]
The impact of microbial metabolism of the organic substituents of low level radioactive wastes on radionuclide mobility in disposal sites, the nature of the microbial transformations involved in this metabolism and the effect of the prevailing environmental parameters on the quantities and types of metabolic intermediates accumulated were examined. Since both aerobic and anaerobic periods can occur during trench ecosystem development, oxidation capacities of the microbial community in the presence and absence of oxygen were analyzed. Results of gas studies performed at three commercial low level radioactive waste disposal sites were reviewed. Several deficiencies in available data were determined. Further research needs are suggested. This assessment has demonstrated that the biochemical capabilities expressed within the low level radioactive waste disposal site are common to a wide variety of soil bacteria. Hence, assuming trenches would not be placed in sites with such extreme abiotic conditions that all microbial activity is precluded, the microbial populations needed for colonization and decomposition of the organic waste substances are readily provided from the waste itself and from the soil of existing and any proposed disposal sites. Indeed, considering the ubiquity of occurrence of the microorganisms responsible for waste decomposition and the chemical nature of the organic waste material, long-term prevention of biodecomposition is difficult, if not impossible.
Evaluation of isotope migration--land bural. Water chemistry at commercially operated low-level radioactive waste disposal sites. Quarterly progress report, January--March 1977
Water samples were collected from ten trenches at the Maxey Flats (Morehead), Kentucky, disposal site in September 1976. Precautions were taken to collect and process the samples under anoxic conditions in accordance with procedures developed for this purpose at Brookhaven National Laboratory. The methods used for the preparation of samples and the analytical techniques employed for inorganic and radiochemical analyses are described. Analytical results of the dissolved radiochemical constituents indicate that all trench water samples contain tritium, strontium-90, and plutonium isotopes. Cobalt-60 and cesium-137 were also detected in most trench water samples. The concentrations of the dissolved inorganic and radiochemical constituents are tabulated for each trench.
Evaluation of isotope migration: land burial water chemistry at commercially operated low-level radioactive waste disposal sites. Quarterly progress report, July--September 1976
This is the second quarterly progress report of water chemistry at commercially operated low-level radioactive waste disposal sites. The program is a joint investigation undertaken by the United States Nuclear Regulatory Commission and the United States Geological Survey as part of a comprehensive plan to study the hydrogeological and geochemical behavior of existing commercially operated low-level radioactive waste disposal sites. The analytical methods that were used to concentrate, separate and identify organic compounds found in filtered trench water samples taken from the Maxey Flats disposal site April 1976 are described. A variety of organic compounds were isolated and identified in all of the trenches sampled.
Evaluation of isotope migration: land burial. Water chemistry at commercially operated low-level radioactive waste disposal sites. Quarterly progress report, October--December 1976
This is the third quarterly progress report of joint USNRC--USGS investigation undertaken as part of a comprehensive plan to study the hydrogeological and geochemical behavior of existing commercially operated low-level radioactive waste disposal sites. Procedures were developed for collecting and filtering trench water samples under anoxic conditions. These procedures prevent the formation of the undesirable brown ferric hydroxide precipitate that generally is encountered when trench water is exposed to air after removal from the ground.
Evaluation of isotope migration: land burial. Water chemistry at commerically operated low-level radioactive waste disposal sites. Progress report No. 5, April--June 1977. [Maxey Flats, Kentucky]
Water samples were collected from ten trenches at the Maxey Flats (Morehead) Kentucky, low-level radioactive waste disposal site and analyzed for the presence of organic compounds. Identification of the organics was achieved by combined gas chromatography--mass spectrometry. Alcohols, aliphatic and aromatic acids, phthalates, adipates, and tributyl phosphate are the predominant kinds of compounds found in most of the trench water samples. These organic compounds may react with the radionuclides buried in the trenches and possibly affect their mobility in the environment.
Side-by-Side Testing of Water Heating Systems: Results from the 2010 - 2011 Evaluation
This document is no longer available. Please contact Stacey.Rothgeb@nrel.gov for further information.
Roof Integrated Solar Absorbers: The Measured Performance of ''Invisible'' Solar Collectors: Preprint
The Florida Solar Energy Center (FSEC), with the support of the National Renewable Energy Laboratory, has investigated the thermal performance of solar absorbers that are an integral, yet indistinguishable, part of a building's roof. The first roof-integrated solar absorber (RISA) system was retrofitted into FSEC's Flexible Roof Facility in Cocoa, Florida, in September 1998. This ''proof-of-concept'' system uses the asphalt shingle roof surface and the plywood decking under the shingles as an unglazed solar absorber. Data was gathered for a one-year period on the system performance. In Phase 2, two more RISA prototypes were constructed and submitted for testing. The first used the asphalt shingles on the roof surface with the tubing mounted on the underside of the plywood decking. The second prototype used metal roofing panels over a plywood substrate and placed the polymer tubing between the plywood decking and the metal roofing. This paper takes a first look at the thermal performance results for the ''invisible'' solar absorbers that use the actual roof surface of a building for solar heat collection.
A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite
NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The appearance of these phases have created very expensive problems in waste treatment plants by fouling process evaporators in the SRS waste processing facility. Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe and predict the formation of NO3 cancrinite and NO3 sodalite. (2) Provide a comprehensive characterization of the solid precipitation rates and mechanisms using novel spectroscopic (e.g., NMR) and thermochemical techniques in conditions encountered in HLW waste solutions. (3) Investigate the ion exchange capacity of these zeolitic phases with respect to radionuclides and RCRA metal species.
A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite (Project No.: 81959)
NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic and alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The appearance of these phases have created very expensive problems in waste treatment plants by fouling process evaporators in the SRS waste processing facility. Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe the formation of NO3 cancrinite and NO3 sodalite. (2) Provide quantification and characterization of the solid precipitation rates through long-term batch kinetic experiments and novel analytical techniques. (3) Investigate the partitioning and ion exchange properties of these zeolitic phases with respect to radionuclides and RCRA metal species. This also includes compositional and structural characterization of ion exchanged solids elucidate the exchange properties of these phases.
A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite
NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The precipitation of alumino-silicate phases from caustic nuclear wastes has proven to be problematic in a number of processes in waste treatment facilities including radionuclide separations (cementation of columns by aluminosilicate phases), tank emptying (aluminosilicate tank heels), and condensation of wastes in evaporators (aluminosilicate precipitates in the evaporators, providing nucleation sites for growth of critical masses of radioactive actinide salts). Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe and predict the formation of NO3 cancrinite and NO3 sodalite. (2) Provide a comprehensive characterization of the solid precipitation rates and mechanisms using novel spectroscopic (e.g., NMR) and thermochemical techniques in conditions encountered in HLW waste solutions. (3) Characterize the precipitation kinetics of the aluminosilicates and study the effects of temperature and fluid composition. (4) Investigate the ion exchange capacity of these zeolitic phases with respect to radionuclides and RCRA metal species.
BASELINE MEMBRANE SELECTION AND CHARACTERIZATION FOR AN SDE
Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In FY05 and FY06, testing at the Savannah River National Laboratory (SRNL) explored a low temperature fuel cell design concept for the SDE. The advantages of this design concept include high electrochemical efficiency and small footprint that are crucial for successful implementation on a commercial scale. A key component of the SDE is the ion conductive membrane through which protons produced at anode migrate to the cathode and react to produce hydrogen. An ideal membrane for the SDE should have both low ionic resistivity and low sulfur dioxide transport. These features allow the electrolyzer to perform at high currents with low potentials, along with preventing contamination of both the hydrogen output and poisoning of the catalysts involved. Another key component is the electrocatalyst material used for the anode and cathode. Good electrocatalysts should be chemically stable and have a low overpotential for the desired electrochemical reactions. This report summarizes results from activities to evaluate commercial and experimental membranes for the SDE. Several different types of commercially-available membranes were analyzed for sulfur dioxide transport as a function of acid strength including perfluorinated sulfonic acid (PFSA), sulfonated poly-etherketone-ketone, and poly-benzimidazole (PBI) membranes. Experimental membranes from the sulfonated diels-alder polyphenylenes (SDAPP) and modified Nafion{reg_sign} 117 were evaluated for SO{sub 2} transport as well. These membranes exhibited reduced transport coefficient for SO{sub 2} transport without the loss in ionic conductivity. The use of Nafion{reg_sign} with EW 1100 is recommended for the present SDE testing due to the limited data regarding chemical and mechanical stability of experimental membranes. Development of new composite membranes by incorporating metal particles or by forming …
EFFECT OF FUEL IMPURITIES ON FUEL CELL PERFORMANCE AND DURABILITY
A fuel cell is an electrochemical energy conversion device that produces electricity during the combination of hydrogen and oxygen to produce water. Proton exchange membranes fuel cells are favored for portable applications as well as stationary ones due to their high power density, low operating temperature, and low corrosion of components. In real life operation, the use of pure fuel and oxidant gases results in an impractical system. A more realistic and cost efficient approach is the use of air as an oxidant gas and hydrogen from hydrogen carriers (i.e., ammonia, hydrocarbons, hydrides). However, trace impurities arising from different hydrogen sources and production increases the degradation of the fuel cell. These impurities include carbon monoxide, ammonia, sulfur, hydrocarbons, and halogen compounds. The International Organization for Standardization (ISO) has set maximum limits for trace impurities in the hydrogen stream; however fuel cell data is needed to validate the assumption that at those levels the impurities will cause no degradation. This report summarizes the effect of selected contaminants tested at SRNL at ISO levels. Runs at ISO proposed concentration levels show that model hydrocarbon compound such as tetrahydrofuran can cause serious degradation. However, the degradation is only temporary as when the impurity is removed from the hydrogen stream the performance completely recovers. Other molecules at the ISO concentration levels such as ammonia don't show effects on the fuel cell performance. On the other hand carbon monoxide and perchloroethylene shows major degradation and the system can only be recovered by following recovery procedures.
PT AND PT/NI "NEEDLE" ELETROCATALYSTS ON CARBON NANOTUBES WITH HIGH ACTIVITY FOR THE ORR
Platinum and platinum/nickel alloy electrocatalysts supported on graphitized (gCNT) or nitrogen doped carbon nanotubes (nCNT) are prepared and characterized. Pt deposition onto carbon nanotubes results in Pt 'needle' formations that are 3.5 nm in diameter and {approx}100 nm in length. Subsequent Ni deposition and heat treatment results in PtNi 'needles' with an increased diameter. All Pt and Pt/Ni materials were tested as electrocatalysts for the oxygen reduction reaction (ORR). The Pt and Pt/Ni catalysts showed excellent performance for the ORR, with the heat treated PtNi/gCNT (1.06 mA/cm{sup 2}) and PtNi/nCNT (0.664 mA/cm{sup 2}) showing the highest activity.
CLOSE-OUT REPORT FOR HYS ELECTROLYZER COMPONENT DEVELOPMENT WORK AT SAVANNAH RIVER NATIONAL LABORATORY
The chemical stability, sulfur dioxide transport, ionic conductivity, and electrolyzer performance have been measured for several commercially available and experimental proton exchange membranes (PEMs) for use in a sulfur dioxide depolarized electrolyzer (SDE). The SDE's function is to produce hydrogen by using the Hybrid Sulfur (HyS) Process, a sulfur based electrochemical/thermochemical hybrid cycle. Membrane stability was evaluated using a screening process where each candidate PEM was heated at 80 C in 63.5 wt. % H{sub 2}SO{sub 4} for 24 hours. Following acid exposure, chemical stability for each membrane was evaluated by FTIR using the ATR sampling technique. Membrane SO{sub 2} transport was evaluated using a two-chamber permeation cell. SO{sub 2} was introduced into one chamber whereupon SO{sub 2} transported across the membrane into the other chamber and oxidized to H{sub 2}SO{sub 4} at an anode positioned immediately adjacent to the membrane. The resulting current was used to determine the SO{sub 2} flux and SO{sub 2} transport. Additionally, membrane electrode assemblies (MEAs) were prepared from candidate membranes to evaluate ionic conductivity and selectivity (ionic conductivity vs. SO{sub 2} transport) which can serve as a tool for selecting membranes. MEAs were also performance tested in a HyS electrolyzer measuring current density versus a constant cell voltage (1V, 80 C in SO{sub 2} saturated 30 wt% H{sub 2}SO{sub 4}). Finally, candidate membranes were evaluated considering all measured parameters including SO{sub 2} flux, SO{sub 2} transport, ionic conductivity, HyS electrolyzer performance, and membrane stability. Candidate membranes included both PFSA and non-PFSA polymers and polymer blends of which the non-PFSA polymers, BPVE-6F and PBI, showed the best selectivity. Testing examined the activity for the sulfur dioxide oxidation of platinum base electrocatalyst in 30 wt% sulfuric acid solution. Linear sweep voltammetry showed an increase in activity when catalysts in which Pt is alloyed with non-noble transition …
FISCAL YEAR 2006 REPORT ON ELECTROLYZER COMPONENT DEVELOPMENT FOR THE HYBRID SULFUR PROJECT
Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In FY05, testing at the Savannah River National Laboratory (SRNL) explored a low temperature fuel cell design concept for the SDE. The advantages of this design concept include high electrochemical efficiency and small volumetric footprint that is crucial for successful implementation on a commercial scale. A key component of the SDE is the ion conductive membrane through which protons produced at anode migrate to the cathode and react to produce hydrogen. An ideal membrane for the SDE should have both low ionic resistivity and low sulfur dioxide transport. These features allow the electrolyzer to perform at high currents with low potentials, along with preventing contamination of both the hydrogen output and poisoning of the catalysts involved. Another key component is the electrocatalyst material used for the anode and cathode. Good electrocatalysts should be chemically stable and low overpotential for the desired electrochemical reactions. This report summarizes results from activities to evaluate different membrane and electrocatalyst materials for the SDE. Several different types of commercially-available membranes were analyzed for ionic resistance and sulfur dioxide transport including perfluorinated sulfonic acid, sulfonated poly-etherketone-ketone, and poly-benzimidazole membranes. Of these membrane types, the poly-benzimidazole (PBI) membrane, Celtec-L, exhibited the best combination of characteristics for use in an SDE. Testing examined the activity and stability of platinum and palladium as electrocatalyst for the SDE in sulfuric acid solutions. Cyclic and linear sweep voltammetry revealed that platinum provided better catalytic activity with much lower potentials and higher currents than palladium. Testing also showed that the catalyst activity is strongly influenced by concentration of the sulfuric acid. Various cell configurations were examined with …
Designing with computers at Lawrence Berkeley Laboratory
No Description Available.
Calculation of magnetic fields for engineering devices
The methodology of magnet technology and its application to various engineering devices are discussed. Magnet technology has experienced a rigid growth in the past few years as a result of the advances made in superconductivity, numerical methods and computational techniques. Included are discussions on: (1) mathematical models for solving magnetic field problems; (2) the applicability, usefulness, and limitations of computer programs that utilize these models; (3) examples of application in various engineering disciplines; and (4) areas where further contributions are needed.
COMPUTER PROGRAMS FOR ACCELERATORS AND ELECTRONIC CIRCUIT DESIGNS.
No Description Available.
Use of Interacting Computing at Lawrence Berkeley Laboratory.
No Description Available.
OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING
This project focused on addressing the two main problems associated with state of art Molten Carbonate Fuel Cells, namely loss of cathode active material and stainless steel current collector deterioration due to corrosion. We followed a dual approach where in the first case we developed novel materials to replace the cathode and current collector currently used in molten carbonate fuel cells. In the second case we improved the performance of conventional cathode and current collectors through surface modification. States of art NiO cathode in MCFC undergo dissolution in the cathode melt thereby limiting the lifetime of the cell. To prevent this we deposited cobalt using an electroless deposition process. We also coated perovskite (La{sub 0.8}Sr{sub 0.2}CoO{sub 3}) in NiO thorough a sol-gel process. The electrochemical oxidation behavior of Co and perovskites coated electrodes is similar to that of the bare NiO cathode. Co and perovskite coatings on the surface decrease the dissolution of Ni into the melt and thereby stabilize the cathode. Both, cobalt and provskites coated nickel oxide, show a higher polarization compared to that of nickel oxide, which could be due to the reduced surface area. Cobalt substituted lithium nickel oxide (LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) and lithium cobalt oxide were also studied. LiNi{sub x}Co{sub 1-x}O{sub 2} was synthesized by solid-state reaction procedure using lithium nitrate, nickel hydroxide and cobalt oxalate precursor. LiNi{sub x}Co{sub 1-x}O{sub 2} showed smaller dissolution of nickel than state of art nickel oxide cathode. The performance was comparable to that of nickel oxide. The corrosion of the current collector in the cathode side was also studied. The corrosion characteristics of both SS304 and SS304 coated with Co-Ni alloy were studied. This study confirms that surface modification of SS304 leads to the formation of complex scales with better barrier properties and better electronic conductivity at 650 …
A FACILITY FOR THE STUDY OF THE EFFECTS OF NUCLEAR RADIATION ON MATERIALS
The Sandia Engineering Reactor Facility consists of a 5-Mw light water moderated heterogeneous-type nuclear reactor, a large dry irradiation room and the necessary laboratory space for the preparation and post-irradiation testing of material samples. This Facility will be used to study the effects of radiation on the engineering properties of materials. Equipment for producing additional environments of heat, cold, altitude and vibration will be available for compounding with the radiation enviroment during material tests. An interesting feature of the operating concept for this facility is the plant to operate the reactor on a continuous, 24-hour per day, seven-day per week basis except for required reactor shut downs. This feature means that provisions must be made in the design of the facitlity to provide for the remote insertion and removal of test objects during full power reactor operation. Instead of having several heavily shielded indiviaual hot cells,'' this facility has one large hot area.'' This hot area'' is separated from the remainder of the Facility by a 42-inch-thick concrete shielding wall containing six high-density lead Argonne Model 8 manipulators. Materials for post-irradiation means of a specically designed Mobile Remote Handler. This Handler is a mobile, electrically driven vehicle containing one man shielded by approximately 6 1/2 in. of lead. (auth)
Aerospace Nuclear Safety Ground Test Program
The assessment (by ground testing) of effects of mechanical actions, thermal and chemical interactions, and nuclear reactions upon tue safety of nuclear power sources that are intended for aerospace applications is discussed. Progress in general studies and in testing of SNAP-9A and -10A is reviewed. (T.F.H.)
Aerospace Nuclear Safety Program at Sandia Corporation. Summary of a Speech
This report describes research, development, support, and test activities in the Sandia Laboratory Aerospace Nuclear Safety Program.
Can the dream of using magma energy come true
No Description Available.
Final report - Magma Energy Research Project
Scientific feasibility was demonstrated for the concept of magma energy extraction. The US magma resource is estimated at 50,000 to 500,000 quads of energy - a 700- to 7000-yr supply at the current US total energy use rate of 75 quads per year. Existing geophysical exploration systems are believed capable of locating and defining magma bodies and were demonstrated over a known shallow buried molten-rock body. Drilling rigs that can drill to the depths required to tap magma are currently available and experimental boreholes were drilled well into buried molten rock at temperatures up to 1100/sup 0/C. Engineering materials compatible with the buried magma environment are available and their performances were demonstrated in analog laboratory experiments. Studies show that energy can be extracted at attractive rates from magma resources in all petrologic compositions and physical configurations. Downhole heat extraction equipment was designed, built, and demonstrated successfully in buried molten rock and in the very hot margins surrounding it. Two methods of generating gaseous fuels in the high-temperature magmatic environment - generation of H/sub 2/ by the interaction of water with the ferrous iron and H/sub 2/, CH/sub 4/, and CO generation by the conversion of water-biomass mixtures - have been investigated and show promise.
FY79 Lava Lake Drilling Program - geoscience studies; plans and results
Fifteen experimental studies were planned for the geoscience studies portion of the FY79 Lava Lake Drilling Program at Kilauea Iki Lava Lake, Hawaii, grouped under headings of petrologic, thermal, strength, liquid/permeability, electrical, and other. This report gives a location, purpose, description, and feasibility analysis for each experiment. A results section for each experiment includes data gathered and analysis to date, where available.
Magma energy: a feasible alternative
A program to investigate the scientific feasibility of extracting energy directly from deeply buried circulating magma sources is described. The following program tasks are discussed: source location and definition, source tapping, magma characterization, magma/material compatibility, and energy extraction. (MHR)
Magma energy: a feasible alternative
A short review of the work performed by Sandia Laboratories in connection with its Magma Energy Research Project is provided. Results to date suggest that boreholes will remain stable down to magma depths and engineering materials can survive the downhole environments. Energy extraction rates are encouraging. Geophysical sensing systems and interpretation methods require improvement, however, to clearly define a buried magma source.
Magma Energy Research Project, FY 1979 annual progress report
The objective of the Magma Energy Research Project is to define the scientific feasibility of extracting energy from magma bodies. Activities to accomplish the objective are divided into five tasks: resource location and identification; source tapping; magma characterization; materials compatibility; and energy extraction. The program activities of FY 1979 are summarized here according to the individual tasks. Major emphasis of the program in the last year was on field experimentation with the United States Geological Survey in geoscience and technological studies at the Kilauea Iki lava lake. Other major efforts included installation of the magma simulation facility and magma-metal compatibility studies. The Magma Energy Advisory Panel also met during this period. Efforts and results are summarized.
Magma Energy Research Project, FY80 annual progress report
The technical feasibility of extracting energy from magma bodies is explored. Five aspects of the project are studied: resource location and definition, source tapping, magma characterization, magma/material compatibility, and energy extraction.
Magma-Tap: the ultimate geothermal energy program
No Description Available.
Underground Protective Buildings
No Description Available.
Sandia Magma Energy Research Project
No Description Available.
Utilization of volcano energy. Proceedings of a conference, Hilo, Hawaii, February 4--8, 1974
No Description Available.
Drilling into molten rock at Kilauea Iki
The scientific feasibility of extracting energy directly from buried circulating magma resources is being assessed. One of the tasks of the project is the study of geophysical measuring systems to locate and define buried molten rock bodies. To verify the results of a molten rock sensing experiment performed at Kilauea Iki lava lake, it is necessary to drill a series of holes through the solid upper crust and through the molten zone at that location. Thirteen holes have been drilled in Kilauea Iki. The results achieved during the drilling of the last two holes indicated that the molten zone in Kilauea Iki is not a simple, relatively homogeneous fluid body as expected. The encountering of an unexpected, unknown rigid obstruction 2.5 ft below the crust/melt interface has led to the conceptual development of a drilling system intended to have the capability to drill through a hot, rigid obstruction while the drill stem is immersed in molten rock. The concept will be field tested at Kilauea Iki in the summer of 1978.
Utilization of magma energy: a project summary
The scientific feasibility of extracting energy from magma bodies is the objective of this project. The high temperature (approx. 1000/sup 0/C) and estimated large resource (approx. 10/sup 4/ quads) within 10 km of the surface in the US provides the incentive for this work. The areal extent of a near-surface molten lava body has been defined with geophysical sensing systems. Improved knowledge of the in situ physical properties of buried molten rock is required to assess the thickness of magma bodies. Drilling into molten lava is a complex operation and requires further technological development. Experimental studies of rock deformation at near-magma temperatures and pressures show that boreholes can be made to stay open. Calculational analyses of magmatic gas samples provide a satisfactory definition of the gas content of in situ magmas. Material compatibility experiments show that Ni- and Co-based alloys can survive and operate in the magma environment. Thermal heat exchangers can survive in molten rock and allow significant rates of heat transfer to an internal fluid.
Magma energy research project: state-of-the-project report, October 1, 1978
The feasibility of extracting energy from magma bodies is investigated. The work done in FY 76, 77, and 78 in the following tasks are summarized; resource location and definition, source tapping, magma characterization and materials compatibility, and energy extraction. (MHR)
Effects of High Neutron and Gamma Fluxes on the Transmission Characteristics of Some Optical Glasses
The design of the Sandia Engineering Reactor Facility (SERF) presented a unique problem of finding a way to view the virtually unshielded 5 Mw reactor during operation. It was determined that periscope viewing was most feasible. The front optical elements of the periscope must withstand a total integrated radiation dose of 3 x 10/sup 9/ of gammas, and 1.4 x 10/sup 7/ n/cm/sup 2/, without excessive transmission losses. A program started to study the effects of radiation at such rates and total doses on the transmission characteristics of available optical glasses is described. Curves plotted from the study are presented to show graphically the results of irradiation on these optical glasses. (W.D.M.)
Magma Energy Research Project. Project summary, July 1, 1974--June 30, 1975
The objective of the Magma Energy Research Project now under way at Sandia Laboratories is to investigate the feasibility of extracting energy directly from deeply buried circulating magma sources. Project plans describe a concept whereby a fully closed heat exchanger system is inserted directly into such a magma source to allow the heat energy to be brought to the surface with minimal environmental impact. A summary of previous efforts is given. The achievements and future plans for source location and definition, source tapping, magma characterization, magma materials compatibilities studies, and energy extraction studies are outlined. (LBS)
Birth of Massive Black Hole Binaries
If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.
Evaluation of the radionuclide concentrations in soil and plants from the 1975 terrestrial survey of Bikini and Eneu Islands
In June 1975 a radiological survey was conducted of the terrestrial environment of Bikini and Eneu islands (Bikini Atoll) to evaluate the potential radiation dose to the returning Bikini population. In this report, we present measurements of the radionuclide concentration in soil profiles and in dominant species of edible and nonedible, indicator plants. The use of these data to derive relationships to predict the plant uptake of radionuclides from soil is described. Approximately 620 soil and vegetation samples from Bikini and Eneu Islands were analyzed by Ge(Li) gamma spectrometry and by wet chemistry. The predominant radionuclides in these samples were /sup 60/Co, /sup 90/Sr, /sup 137/Cs, /sup 239,240/Pu, /sup 241/Pu, and /sup 241/Am.
Derivation of plant-soil relationships for dose assessment on Bikini Atoll. [Radiation dose to returning population]
A radiological survey of the terrestrial environment of Bikini and Eneu Islands (Bikini Atoll) was conducted in June 1975 to evaluate the potential radiation dose to the returning Bikini population. This report presents measurements of the radionuclide concentration in soil profiles and in dominant species of edible and nonedible indicator plants and describes the use of these data to derive relationships to predict the plant uptake of radionuclides from soil. Soil-plant concentration factors together with leaf-leaf and fruit-leaf concentration ratios for indicator and edible plant species from the same area are calculated to quantitatively assess and compare the uptake of /sup 90/Sr, /sup 137/Cs, and /sup 239/'/sup 240/Pu. In general, the concentration factors for /sup 137/Cs in terrestrial vegetation are greater than those for /sup 90/Sr and the concentration factors for both these nuclides exceed those for /sup 239/'/sup 240/Pu by ten to one hundred-fold. Uptake of /sup 90/Sr and /sup 239/'/sup 240/Pu by fruit is less than that by mature leaves; however, the opposite is true for /sup 137/Cs. The relative contribution of the individual plant species to the internal dose to man varies with the nuclide. The use of concentration factors and concentration ratios to predict nuclide concentrations in fruit from those in soil or leaves is prescribed.
Backwater and Discharge at Highway Crossing with Multiple Bridges in Louisiana and Mississippi
Purpose and Scope: The principal objective of this project was to measure the backwater and discharge distribution for multiple bridges. These data have been used to determine if the methods developed by Schneider and others (1976) for single-opening highway crossings could be applied to multiple bridges. In addition, the method developed by Tracey and Carter (1955) and Cragwall (1958) was modified to use the procedure proposed by Schneider and others (1976) to calculate friction losses in the approach reach. This modified procedure was then also tested.
Back to Top of Screen