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3-D field computations for accelerator magnets using finite element and integral codes (open access)

3-D field computations for accelerator magnets using finite element and integral codes

Two dimensional (2-D) computation has been an accepted part of the design of accelerator magnets since the 1960`s, but three-dimensional (3-D) computations are still not fully trusted. This paper describes the successes and limitations of 3-D computations, as applied to accelerator magnets for the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Both the finite element code TOSCA and the edge element volume integral code CORAL have been used in these computations. The ends of the dipole bending magnet for the injector synchrotron were designed using TOSCA; comparisons with measurements are described. Computation of other APS magnets are also described.
Date: December 1, 1992
Creator: Turner, L. R.; Kim, S. H.; Kim, K. & Kettunen, L.
System: The UNT Digital Library
The 400 MeV Linac Upgrade at Fermilab (open access)

The 400 MeV Linac Upgrade at Fermilab

The Fermilab Linac Upgrade in planned to increase the energy of the H[sup [minus]] linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHs drift-tube linac (DTL) tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MRs side-coupled cavity modules operating at an average axial field of about 7.5 MV/meter. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a 12 MW klystron-based rf power supply. Three of seven accelerator modules have been fabricated, power tested and installed in their temporary location adjacent to the existing DTL. All seven RF Modulators have been completed and klystron installation has begun. Waveguide runs have completed from the power supply gallery to the accelerator modules. The new linac will be powered in the temporary position without beam in order to verify overall system reliability until the laboratory operating schedule permits final conversion to 400 MeV operation.
Date: December 1, 1992
Creator: Noble, R.J.
System: The UNT Digital Library
The 400 MeV Linac Upgrade at Fermilab (open access)

The 400 MeV Linac Upgrade at Fermilab

The Fermilab Linac Upgrade in planned to increase the energy of the H{sup {minus}} linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHs drift-tube linac (DTL) tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MRs side-coupled cavity modules operating at an average axial field of about 7.5 MV/meter. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a 12 MW klystron-based rf power supply. Three of seven accelerator modules have been fabricated, power tested and installed in their temporary location adjacent to the existing DTL. All seven RF Modulators have been completed and klystron installation has begun. Waveguide runs have completed from the power supply gallery to the accelerator modules. The new linac will be powered in the temporary position without beam in order to verify overall system reliability until the laboratory operating schedule permits final conversion to 400 MeV operation.
Date: December 1992
Creator: Noble, Robert J.
System: The UNT Digital Library
Amorphization kinetics of Zr(Cr,Fe){sub 2} under ion irradiation (open access)

Amorphization kinetics of Zr(Cr,Fe){sub 2} under ion irradiation

Thin foils of Zircaloy-4 were irradiated with 350 KeV {sup 40}Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300--650 K. The irradiation-induced amorphization of the intermetallic precipitates Zr (Cr; Fe){sub 2} and Zr{sub 2} (Ni, Fe) was studied in-situ. For Zr (Cr, Fe){sub 2} precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr{sub 2} (Ni,Fe) precipitates it was found that amorphization occurred at 550 and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in context of previous neutron and electron irradiations and likely amorphization mechanisms are proposed.
Date: December 1, 1992
Creator: Motta, A. T.; Howe, L. M. & Okamoto, P. R.
System: The UNT Digital Library
Amorphization kinetics of Zr(Cr,Fe)[sub 2] under ion irradiation (open access)

Amorphization kinetics of Zr(Cr,Fe)[sub 2] under ion irradiation

Thin foils of Zircaloy-4 were irradiated with 350 KeV [sup 40]Ar ions in the dual ion beam/HVEM facility at Argonne National Laboratory at 300--650 K. The irradiation-induced amorphization of the intermetallic precipitates Zr (Cr; Fe)[sub 2] and Zr[sub 2] (Ni, Fe) was studied in-situ. For Zr (Cr, Fe)[sub 2] precipitates the dose-to-amorphization was found to increase exponentially with temperature, with a critical temperature of about 650 K. The amorphization morphology was shown to be homogeneous, with no preferential site for nucleation, in contrast to neutron-irradiation amorphization which started at the precipitate-matrix interface. For Zr[sub 2] (Ni,Fe) precipitates it was found that amorphization occurred at 550 and 600 K, whereas in neutron irradiation no amorphization has been observed at those temperatures. The results are discussed in context of previous neutron and electron irradiations and likely amorphization mechanisms are proposed.
Date: December 1, 1992
Creator: Motta, A.T. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Nuclear Engineering); Howe, L.M. (Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Labs.) & Okamoto, P.R. (Argonne National Lab., IL (United States))
System: The UNT Digital Library
Analysis and correction of noise on electronic circuits in an accelerator environment (open access)

Analysis and correction of noise on electronic circuits in an accelerator environment

Accelerator noise sources can cause both analog and digital electronic circuits to malfunction. This paper identifies and analyzes noise sources, and describes the methodology for measurement. Both general remedies and specific solutions to minimize the noise effects on accelerator electronic circuits are described. A policy for electronic design, board layout, assembly, and fabrication is established. Conclusions are drawn based on theoretical principles with practical examples shown in case studies.
Date: December 1, 1992
Creator: Fathizadeh, M.; Despe, O. D. & McGhee, D. G.
System: The UNT Digital Library
Analysis of a proposed Compton backscatter imaging technique (open access)

Analysis of a proposed Compton backscatter imaging technique

Imaging techniques which require access to only one side of the object being viewed are potentially useful in situations where conventional projection radiography and tomography cannot be applied, such as looking for voids in a large container where access to the back of the object is inconvenient or even impossible. One-sided imaging techniques are currently being used in nondestructive evaluation of surfaces and shallow subsurface structures. In this work we present both analytical calculations and detailed Monte Carlo simulations aimed at assessing the capability of a proposed Compton backscatter imaging technique designed to detect and characterize voids located several centimeters below the surface of a solid. The proposed technique, based on a scheme suggested by Farmer and Collins, encodes the spatial position and structure of voids in a solid in the energy spectrum of the Compton-scattered photons as recorded by a high resolution detector. Our calculations model a {sup 137}Cs source projecting a 1 mm{sup 2} pencil beam of 662 keV gammas into a target slab at an incident angle of 45{degrees} and a collimated detector (also oriented at 45{degrees} with respect to the surface) which views the beam path at a central angle of 90{degrees}. The detector collimator is …
Date: December 1, 1992
Creator: Hall, J. & Jacoby, B.
System: The UNT Digital Library
Analysis of magnetic energy stored in superconducting coils with and without ferromagnetic inserts (open access)

Analysis of magnetic energy stored in superconducting coils with and without ferromagnetic inserts

Inductance and energy of superconducting coils are calculated by (1) a long solenoid approximation, (2) a finite element model, and (3) working formulas and tables. The results of the finite element model compare favorably with that of the working formulas. The long solenoid approximation overpredicts the energy and the inductance compared to the other two methods. The difference decreases with increasing length to diameter ratio.
Date: December 1, 1992
Creator: Cha, Y. S.
System: The UNT Digital Library
Analytical analyses of startup measurements associated with the first use of LEU fuel in Romania`s 14-MW TRIGA reactor (open access)

Analytical analyses of startup measurements associated with the first use of LEU fuel in Romania`s 14-MW TRIGA reactor

The 14-MW TRIGA steady state reactor (SSR) is located in Pitesti, Romania. Beginning with an HEU core (10 wt% U), the reactor first went critical in November 1979 but was shut down ten years later because of insufficient excess reactivity. Last November the Institute for Nuclear Research (INR), which operates the SSR, received from the ANL RERTR program a shipment of 125 LEU pins fabricated by General Atomics and of the same geometry as the original fuel but with an enrichment of 19.7% 235U and a loading of 45 wt% U. Using 100 of these pins, four LEU clusters, each containing a 5 x 5 square array of fuel rods, were assembled. These four LEU clusters replaced the four most highly burned HEU elements in the SSR. The reactor resumed operations last February with a 35-element mixed HEU/LEU core configuration. In preparation for full power operation of the SSR with this mixed HEU/LEU core, a number of measurements were made. These included control rod calibrations, excess reactivity determinations, worths of experiment facilities, reaction rate distributions, and themocouple measurements of fuel temperatures as a function of reactor power. This paper deals with a comparison of some of these measured reactor parameters …
Date: December 1, 1992
Creator: Bretscher, M. M.; Snelgrove, J. L. & Ciocanescu, M.
System: The UNT Digital Library
Application of neutron diffraction technology to the determination of residual strain in engineering composites (open access)

Application of neutron diffraction technology to the determination of residual strain in engineering composites

Knowledge of fabrication induced residual stresses in the fiber and matrix of advanced engineering composites is important as these stresses can greatly influence the mechanical properties of these composites. In this paper, the application of neutron diffraction technology to the determination of thermal residual strains in the constituents of composites (from which stresses can be calculated) is discussed. Experimental determination of temperature dependent strain in the fiber and matrix of three composites compare favorably with the results of analytical and finite element methods used to predict strain. These composites (two ceramic matrix and one metal matrix) are materials of interest to a variety of industries. In this paper, the benefit of applying a National Laboratory developed technology to a problem of interest to industry, is shown.
Date: December 1, 1992
Creator: Kupperman, D. S.
System: The UNT Digital Library
The APS linac beam position monitors and electronics (open access)

The APS linac beam position monitors and electronics

Beam position monitors using stripline pickups for 30 ns long electron and positron beam bunches have been built and responses were measured in the vertical and horizontal directions. Log amplifiers used for signal processing have a dynamic range of 40 dB and are scaled for 50 mV/dB sensitivity. In this paper we describe the design of the detectors, the signal processing electronics, and the results of the position-to-signal mapping using a wire. Beam position measurements using a prototype detector and electronics on the APS linac test stand are discussed.
Date: December 1, 1992
Creator: Fuja, R. & Chung, Youngjoo
System: The UNT Digital Library
Assessment of the facilities on Jackass Flats and other Nevada Test Site facilities for the new nuclear rocket program (open access)

Assessment of the facilities on Jackass Flats and other Nevada Test Site facilities for the new nuclear rocket program

Recent NASA/DOE studies for the Space Exploration Initiative have demonstrated a critical need for the ground-based testing of nuclear rocket engines. Experience in the ROVER/NERVA Program, experience in the Nuclear Weapons Testing Program, and involvement in the new nuclear rocket program has motivated our detailed assessment of the facilities used for the ROVER/NERVA Program and other facilities located at the Nevada Test Site (NTS). The ROVER/NERVA facilities are located in the Nevada Research L, Development Area (NRDA) on Jackass Flats at NTS, approximately 85 miles northwest of Las Vegas. To guide our assessment of facilities for an engine testing program we have defined a program goal, scope, and process. To execute this program scope and process will require ten facilities. We considered the use of all relevant facilities at NTS including existing and new tunnels as well as the facilities at NRDA. Aside from the facilities located at remote sites and the inter-site transportation system, all of the required facilities are available at NRDA. In particular we have studied the refurbishment of E-MAD, ETS-1, R-MAD, and the interconnecting railroad. The total cost for such a refurbishment we estimate to be about $253M which includes additional contractor fees related to indirect, …
Date: December 1, 1992
Creator: Chandler, G.; Collins, D.; Dye, K.; Eberhart, C.; Hynes, M.; Kovach, R. et al.
System: The UNT Digital Library
ATW system impact on high-level waste (open access)

ATW system impact on high-level waste

This report discusses the Accelerator Transmutation of Waste (ATW) concept which aims at destruction of key long-lived radionuclides in high-level nuclear waste (HLW), both fission products and actinides. This focus makes it different from most other transmutation concepts which concentrate primarily on actinide burning. The ATW system uses an accelerator-driven, sub-critical assembly to create an intense thermal neutron environment for radionuclide transmutation. This feature allows rapid transmutation under low-inventory system conditions, which in turn, has a direct impact on the size of chemical separations and materials handling components of the system. Inventories in ATW are factors of eight to thirty times smaller than reactor systems of equivalent thermal power. Chemical separations systems are relatively small in scale and can be optimized to achieve high decontamination factors and minimized waste streams. The low-inventory feature also directly impacts material amounts remaining in the system at its end of life. In addition to its low-inventory operation, the accelerator-driven neutron source features of ATW are key to providing a sufficient level of neutrons to allow transmutation of long-lived fission products.
Date: December 1, 1992
Creator: Arthur, E. D.
System: The UNT Digital Library
Basic concepts underlying fast-neutron-based contraband interrogation technology. A systems viewpoint (open access)

Basic concepts underlying fast-neutron-based contraband interrogation technology. A systems viewpoint

All accelerator-based fast-neutron contraband interrogation systems have many closely interrelated subsystems, whose performance parameters will be critically interdependent. For optimal overall performance, a systems analysis design approach is required. This paper provides a general overview of the interrelationships and the tradeoffs to be considered for optimization of nonaccelerator subsystems.
Date: December 1, 1992
Creator: Fink, C. L.; Guenther, P. T. & Smith, D. L.
System: The UNT Digital Library
Biases in Monte Carlo eigenvalue calculations (open access)

Biases in Monte Carlo eigenvalue calculations

The Monte Carlo method has been used for many years to analyze the neutronics of nuclear reactors. In fact, as the power of computers has increased the importance of Monte Carlo in neutronics has also increased, until today this method plays a central role in reactor analysis and design. Monte Carlo is used in neutronics for two somewhat different purposes, i.e., (a) to compute the distribution of neutrons in a given medium when the neutron source-density is specified, and (b) to compute the neutron distribution in a self-sustaining chain reaction, in which case the source is determined as the eigenvector of a certain linear operator. In (b), then, the source is not given, but must be computed. In the first case (the ``fixed-source`` case) the Monte Carlo calculation is unbiased. That is to say that, if the calculation is repeated (``replicated``) over and over, with independent random number sequences for each replica, then averages over all replicas will approach the correct neutron distribution as the number of replicas goes to infinity. Unfortunately, the computation is not unbiased in the second case, which we discuss here.
Date: December 1, 1992
Creator: Gelbard, E. M.
System: The UNT Digital Library
Bulk solubility and speciation of plutonium(VI) in phosphate-containing solutions (open access)

Bulk solubility and speciation of plutonium(VI) in phosphate-containing solutions

The solubility and speciation of Pu(VI) with phosphate as a function of pH was investigated to determine the ability of phosphate to act as an actinide getter. The general properties were first investigated and are reported here with the goal of performing more quantitative experiments in the future. Solubility was approached from oversaturation at initial pH = 4, 10 and 13.4. Absorption spectra were recorded, the solution filtered and the filtrate counted. Absorption spectra were obtained at varying phosphate concentrations and at pH of 2.7 to 11.9. The effect of complexation on the 833 mn Pu(VI) band was characterized. Evidence for three phosphate complexes was obtained for pH < 10 which have absorption bands at 842, 846 and 849 mn. Evidence for colloid formation was observed but is not conclusive. The possibility of colloids prevents accurate analysis of the solubility experiments. A concentration of 10{sup {minus}5} to 10{sup {minus}6} M Pu(VI) was measured in the filtrate at pH {le} 10 that were passed through a 50 mn filter. Pu(VI) complexes with phosphate over hydroxide at pH {le} 11.6, but at pH {ge} 11.9, only hydrolyzed Pu(VI) was detected. At pH = 12, the concentration of Pu(VI) was as high as …
Date: December 1, 1992
Creator: Weger, H. T.; Okajima, S.; Cunnane, J. C. & Reed, D. T.
System: The UNT Digital Library
A Calcium Oxide Sorbent Process for Bulk Separation of Carbon Dioxide (open access)

A Calcium Oxide Sorbent Process for Bulk Separation of Carbon Dioxide

The overall project is divided into two phases. Phase I, now complete, investigated the technical feasibility of a regenerable calcium sorbent-based process for the high-temperature, high-pressure (HTHP) separation of CO{sub 2} from coal-derived gas. A high-pressure electrobalance reactor and microgram quantities of sorbent were used in this phase of the study. Favorable results led to continuation of the project into Phase II where a laboratory-scale fixed-bed reactor involving gram quantities of sorbent and with capability for product gas analysis is being used. The possibility of the simultaneous occurrence of the water-gas shift reaction and CO{sub 2} separation is of particular interest in Phase II. Simultaneous reactions create the possibility of a direct, one-step process for producing hydrogen from coal-derived gas.
Date: December 1, 1992
Creator: Harrison, D. P.; Silaban, A.; Narcida, M. & Han, C.
System: The UNT Digital Library
Chaotic vibrations of tubes with nonlinear supports in crossflow (open access)

Chaotic vibrations of tubes with nonlinear supports in crossflow

By means of the unsteady flow theory and a bilinear mathematical model, a theoretical study is presented for chaotic vibrations associated with the fluidelastic instability of nonlinearly supported tubes in a crossflow. A series of effective tools, including phase portraits, power spectral density, Poincar`e maps, Lyapunov exponent, fractal dimension, and bifurcation diagrams, are utilized to distinguish periodic and chaotic motions when the tubes vibrate in the instability region. Results show periodic and chaotic motions in the region corresponding to the fluid damping controlled instability. Nonlinear supports, with symmetric or asymmetric gaps, significantly affect the distributions of periodic, quasiperiodic and chaotic motions of the tube with various flow velocity in the instability region of the TSP(tube-support-plate)-inactive mode.
Date: December 1, 1992
Creator: Cai, Y. & Chen, S. S.
System: The UNT Digital Library
Characterization of electrochemical systems and batteries: Materials and systems (open access)

Characterization of electrochemical systems and batteries: Materials and systems

Materials are a pacing problem in battery development. The battery environment, particularly in rechargeable batteries, places great demands on materials. Characterization of battery materials is difficult because of their complex nature. In many cases meaningful characterization requires iii situ methods. Fortunately, several new electrochemical and spectroscopic techniques for in situ characterization studies have recently become available, and reports of new techniques have become more frequent. The opportunity now exists to utilize advanced instrumentation to define detailed features, participating chemical species and interfacial structure of battery materials with a precision heretofore not possible. This overview gives key references to these techniques and discusses the application of x-ray absorption spectroscopy to the study of battery materials.
Date: December 1, 1992
Creator: McBreen, J.
System: The UNT Digital Library
Chemical and mechanical recycling of shredder fluff (open access)

Chemical and mechanical recycling of shredder fluff

Each year, the secondary metals industry recovers about 55--60 million tons of prompt and obsolete scrap which is used in the production of finished steel products. The single largest source of this scrap is the obsolete automobile. The shredder industry recovers about 10--12 million ton/yr of ferrous scrap, most of which is from shredded automobiles. However, for each ton of steel recovered, over 500 lb of fluff are produced. Shredder fluff is comprised of the nonmetallic content of the automobile and other shredded materials, such as refrigerators, dryers, and dishwashers, which are commonly called white goods. The plastics content of shredder fluff is typically about 15--20% by weight and is expected to increase over the next decade due to the significant increase in the use of automotive plastics over the past 10--15 years. At present, shredder fluff is landfilled. The rapidly escalating landfilling cost, along with environmental concerns over the fate of this waste, poses a significant cost and liability to the shredder industry. Research is being carried out to identify and develop recycling technologies that will reduce the volume and the mass of shredder fluff going to landfills and to minimize its cost impact on the recycling of secondary …
Date: December 1, 1992
Creator: Jody, B. J.; Daniels, E. J.; Bonsignore, P. V. & Shoemaker, E. L.
System: The UNT Digital Library
Coal ash behavior in reducing environments (open access)

Coal ash behavior in reducing environments

A key factor in the successful design and operation of coal gasification systems is the ability to control and mitigate ash-related problems. Some of the major ash-related problems are slag flow control, slag attack on the refractory, ash deposition on heat-transfer surfaces, corrosion and erosion of equipment materials, and emissions control. Such problems are closely tied to the abundance and association of the inorganic components in coal and the gasification conditions. The CABRE project is a three-year program designed to investigate the transformations and properties of coal ash in reducing environment systems. The CABRE project is organized into a three-task structure which is the backbone of the project`s strength. Task 1, Analytical Methods Development, has concentrated on the special needs of analyzing samples produced under a reducing atmosphere as opposed to the more often studied combustion systems. Task 2, Inorganic Partitioning and Ash Deposition, has focused on the production of gasification-type samples under closely controlled conditions for the study of inorganic partitioning that may lead to deposition. Task 3, Ash and Slag Physical Properties, has made large gains in the areas of sintering and strength development of coal ashes under reducing atmospheres for the evaluation of deposition problems.
Date: December 1, 1992
Creator: Erickson, T. A.; Benson, S. A.; Steadman, E. N.; Brekke, D. W.; Folkedahl, B. C.; Tibbetts, J. E. et al.
System: The UNT Digital Library
Coal gasification for the coproduction of electricity and fertilizer (open access)

Coal gasification for the coproduction of electricity and fertilizer

TVA is proposing to develop and commercially demonstrate the coproduction of electricity and fertilizer (urea) using integrated gasification/combined cycle (IGCC) technology. The coal-based coproduction demonstration project will show that the coproduction process can economically and environmentally enhance the production of both electric power and urea. As conceptualized, the proposed coproduction demonstration project facility would be designed for a nominal electrical capacity of about 250 megawatts (MW), Table I. During normal operation, the facility would produce about 150 MW of base-load electrical power and 1,000 tons per day of urea. Sulfur from the coal would be recovered as elemental sulfur. During peak power demand, the fertilizer capacity could be reduced or bypassed and the full 250 MW could be made available. This scheme would allow continuous operation of the gasifier at 100% of its rated capacity which would reduce the annual revenue requirements for power generation by permitting the production of fertilizer. As TVA`s vision of this proposal matures (i.e., as consideration is given to alternative schemes, as TVA reviews its power demands, and as more detailed engineering estimates are developed), the nature and scope of cyclic-operation may be altered.
Date: December 1, 1992
Creator: Kelly, D. A.; Nichols, D. E. & Faucett, H. L.
System: The UNT Digital Library
Commercialization of coal-fueled gas turbine systems (open access)

Commercialization of coal-fueled gas turbine systems

The overall goal of this program is to develop and demonstrate the technological bases for economically attractive, commercial, coal- fired gas turbine systems. Objectives to accomplish this goal include these: identify candidate technical approaches to meet the challenges of using coal as a turbine fuel, screen the candidate technical approaches by testing their relative performance and evaluating their effects on the economic attractiveness of commercial coal-fueled systems, demonstrate the most promising technologies and associated components in proof-of-concept system tests leading up to commercialization. This paper presents background information on the project, and results on cogeneration systems, combined cycle power plants to include performance and cost.
Date: December 1, 1992
Creator: Wilkes, C. & Wenglarz, R. A.
System: The UNT Digital Library
Considerations of the low-velocity stage of a radioactive beams accelerator (open access)

Considerations of the low-velocity stage of a radioactive beams accelerator

Studies of the low-velocity stages of a radioactive beams accelerator are summarized, highlighting the limitations of existing RFQ technology when applied to the specifications of the IsoSpin Laboratory.
Date: December 1, 1992
Creator: Talbert, W. L.
System: The UNT Digital Library