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Application of analytical electron microscopy to the study of intergranular corrosion in 304 stainless steel

Description: The technique of analytical electron microscopy in a scanning transmission electron microscope fitted with an energy dispersive x-ray spectrometer is used to measure the chromium depletion in sensitized 304 stainless steel along the grain boundaries. It is shown that such measurements could be misleading unless care is taken to properly choose the regions on the grain boundaries for such analysis.
Date: January 1, 1980
Creator: Pande, C S & Sabatini, R L
Partner: UNT Libraries Government Documents Department

Critical study of type II supernovae: equations of state and general relativity

Description: The relevance of relativistic gravitation and of the properties of nuclear matter at high density to supernova explosions is examined in detail. The existing empirical knowledge on the nuclear equation of state at densities greater than saturation, extracted from analysis of heavy ion collisions and from the breathing mode in heavy nuclei, is also considered. Particulars of the prompt explosions recently obtained theoretically by Baron, Cooperstein, and Kahana are presented. 40 refs., 9 figs., 3 tabs.
Date: January 1, 1986
Creator: Kahana, S.
Partner: UNT Libraries Government Documents Department

Collapse of accreting carbon-oxygen white dwarfs induced by carbon deflagration at high density

Description: A critical condition is obtained for which carbon deflagration induces collapse of an accreting C + O white dwarf, not explosion. If the carbon deflagration is initiated at central density as high as 10/sup 10/ g cm/sup -3/ and if the propagation of the deflagration wave is slower than approx. 0.15 upsilon/sub s/ (upsilon/sub s/ is the sound speed), electron capture behind the burning front induces collapse to form a neutron star. This is the case for both conductive and convective deflagrations. Such a high central density can be reached if the white dwarf is sufficiently massive and cold at the onset of accretion and if the accretion rate is in the appropriate range. Models for Type Ia and Ib supernovae are also discussed. 66 refs., 8 figs.
Date: January 1, 1986
Creator: Nomoto, K.
Partner: UNT Libraries Government Documents Department

BNL kaon beams, present and planned

Description: At the present time, there are three electrostatically purified (separated) kaon beams in operation at the Brookhaven AGS. They are optimized for .8 GeV/c, 1.1 GeV/c and 6 GeV/c. A fourth beam has been designed for a maximum momentum of 2.0 GeV/c. It features two-stage purification and higher order optical corrections. Anticipated performance figures for the beam, which is capable of delivering more than 10/sup 6/ kaons per spill, are given, as well as measured performance figures for the existing beams. Possible purification schemes for momenta above 6 GeV/c are discussed. Performance data from neutral and unpurified beams are presented.
Date: January 1, 1986
Creator: Lazarus, D.M.
Partner: UNT Libraries Government Documents Department

Application of synchrotron radiation to x-ray fluorescence analysis of trace elements

Description: The development of synchrotron radiation x-ray sources has provided the means to greatly extend the capabilities of x-ray fluorescence analysis for determinations of trace element concentrations. A brief description of synchrotron radiation properties provides a background for a discussion of the improved detection limits compared to existing x-ray fluorescence techniques. Calculated detection limits for x-ray microprobes with micrometer spatial resolutions are described and compared with experimental results beginning to appear from a number of laboratories. The current activities and future plans for a dedicated x-ray microprobe beam line at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory are presented.
Date: August 1, 1986
Creator: Gordon, B.M.; Jones, K.W. & Hanson, A.L.
Partner: UNT Libraries Government Documents Department

Detector issues for relativistic heavy ion experimentation

Description: Several aspects of experiments using relativistic heavy ion beams are discussed. The problems that the current generation of light ion experiments would face in using gold beams are noted. A brief review of colliding beam experiments for heavy ion beams is contrasted with requirements for SSC detectors. 11 refs., 13 figs.
Date: April 1, 1986
Creator: Gordon, H.
Partner: UNT Libraries Government Documents Department

Development of an x-ray fluorescence microprobe at the National Synchrotron Light Source, Brookhaven National Laboratory: Early results: Comparison with data from other techniques

Description: Theoretical predictions for the detection levels in x-ray fluorescence analysis with a synchrotron storage ring are being achieved experimentally at several laboratories. This paper is deliberately restricted to the state of development of the Brookhaven National Laboratory/University of Chicago instruments. Analyses at the parts per million (ppM) level are being made using white light apertured to 20 ..mu..m and an energy dispersive system. This system is particularly useful for elements with Z > 20 in materials dominated by elements with Z < 20. Diffraction causes an interference for crystalline materials. Development of a focusing microprobe for tunable monochromatic x-rays and a wavelength dispersive spectrometer (WDS) is delayed by problems in shaping an 8:1 focusing mirror to the required accuracy. Reconnaissance analyses with a wiggler source on the CHESS synchrotron have been made in the K spectrum up to Z = 80.
Date: January 1, 1986
Creator: Smith, J.V.; Rivers, M.L.; Sutton, S.R.; Jones, K.W.; Hanson, A.L. & Gordon, B.M.
Partner: UNT Libraries Government Documents Department

Direct heating containment vessel interactions code (DHCVIC) and prediction of SNL ''SURTSEY'' test DCH-1

Description: High-pressure melt ejection from PWR vessels has been identified as a severe core accident scenario which could potentially lead to ''early'' containment failure. Melt ejection, followed by dispersal of the melt by high velocity steam in the cavity beneath the PWR vessel could, according to this scenario, lead to rapid transfer of energy from the melt droplets to the containment atmosphere. This paper describes DHCVIC, an integrated model of the thermal, chemical and hydrodynamic interactions which are postulated to take place during high-pressure melt ejection sequences. The model, which characterizes vessel (or building), is applied to prediction of the Sandia National Laboratory ''SURTSEY'' Test DCH-1 and a (post-test) prediction of that test is made.
Date: January 1, 1986
Creator: Ginsberg, T. & Tutu, N.
Partner: UNT Libraries Government Documents Department

Nuclear data for production of /sup 117m/Sn for biomedical application

Description: The /sup 117m/Sn(4+)DTPA has been shown to have high uptake in cortical bone with negligible soft-tissue deposition. The long half-life (14 d) of /sup 117m/Sn and its emission of abundant short-range Auger and conversion electrons, make /sup 117m/Sn(4+)DTPA an attractive therapeutic agent for bone tumors. The necessary nuclear data for production of clinical quantities of /sup 117m/Sn using Sb(p,2pxn) reactions at BLIP was obtained. The excitation functions for /sup 121/Sb(p,2p3n) and /sup 123/Sb(p,2p5n) reactions in the regions of 43 less than or equal to E/sub p/ less than or equal to 60 MeV were measured and compared with predicted values obtained from semi-empirical formulae given by Silberberg and Tsao. /sup 117m/Sn is routinely produced at ORNL by thermal neutron activation of /sup 116/Sn. We have investigated the possibility of improving the specific activity of the reactor-produced /sup 117m/Sn by irradiating enriched /sup 116/Sn and /sup 117/Sn in the core of the HFBR. Our results indicate that, due to a strong absorption resonance at E/sub n/ approx. = 110 eV, better specific activity for reactor-produced /sup 117m/Sn can be obtained by irradiating natural tin in the core of a reactor. 7 refs., 1 fig. 1 tab.
Date: January 1, 1985
Creator: Mausner, L.F.; Mirzadeh, S. & Ward, T.E.
Partner: UNT Libraries Government Documents Department

Single particle excitations in RbAg/sub 4/I/sub 5/

Description: In an inelastic neutron experiment on RbAg/sub 4/I/sub 5/ a broad quasielastic peak was observed throughout Q-space. As the temperature was lowered, the quasielastic peak became a broad propagating excitation with dirac constant ..omega.. approx. 2.2 meV. This excitation was measured along several symmetry directions and it exhibited little dispersion. This confirms that the original idea of a single particle excitation corresponding to the Ag/sup +/ ions moving within a potential well created by the rest of the lattice. The temperature dependence of this excitation is consistent with recent calculations of neutron scattering in superionic conductors.
Date: January 1, 1979
Creator: Shapiro, S.M. & Salamon, M.B.
Partner: UNT Libraries Government Documents Department

Analysis of MSIV-ATWS events with the BNL plant analyzer

Description: There are automatic safety features and operator-initiated emergency procedures which influence the sequence of events until the time when the standby liquid control system (SLCS), or other attempts to get control rods inserted, can effect shutdown of the core. One emergency procedure for a BWR/4 would require the operator to reduce the flow of high pressure coolant injection (HPCI) into the reactor. The core inlet flow rate at this time would be due to natural circulation and the reduced flow would lower the water level in the downcomer thereby reducing the natural circulation flow rate. This effect, and the reduction in core inlet subcooling due to mixing of the emergency feedwater with steam in the downcomer when the level was lowered, cause a sufficient increase in core void fraction so that the power would be reduced. A reduction in pressure might also be called for during this event in order to comply with the PSP heat capacity temperature limit (or possibly to prevent cycling of relief valves). In the past few years there have been several studies of this problem with the emphasis on calculating the power level in the core. In the present study we consider the power level as well as the resulting PSP temperature and take into account different assumptions regarding plant parameters and operator actions.
Date: June 1, 1986
Creator: Diamond, D.J.
Partner: UNT Libraries Government Documents Department

eP physics at the CBA

Description: In this report we have tried to demonstrate how a 20 x 400 GeV ep facility at the CBA will complement the physics of high energy e/sup -/e/sup +/ and hadron-hadron colliders. An ep collider will extend tests of the standard model by about an order of magnitude in spacelike momentum transfer, and extend our knowledge of electro-weak processes to a remarkable degree. It will be especially interesting to see if the lefthanded nature of the charged current observed at low spacelike momentum transfers persists to large, space momentum transfers. A high energy ep collider is unique in the opportunity to investigate QCD through the scale breaking at high Q/sup 2/ the high P/sub t/ QCD Compton process. In addition to probing small distance behavior in kinematic regions orthogonal to other collider facilities, an ep facility will generate data ultimately crucial to the understanding of the physics of e/sup +/e/sup -/ and hadron-hadron collisions. The current jet that is produced in the high energy ep neutral current process recoils against a single electron which can be used to predict the momentum of the quark which gives rise to the jet. The central problem in jet physics of deducing the kinematics of a quark by measurement of its hadronization jet can be studied under uniquely controlled circumstances. Finally the high Q/sup 2/ structure functions of the proton which are essential in understanding hard processes in hadron-hadron scattering can only be cleanly measured in an ep collider.
Date: January 1, 1982
Creator: Wiss, J.E.; White, D.H. & Morse, W.M.
Partner: UNT Libraries Government Documents Department

Initiation of stress corrosion cracking of sensitized type 304 stainless steel

Description: The corrosion potential of stressed sensitized Type 304 stainless steels were studied in oxygen-containing solutions to determine the relation between potential fluctuations and the initiation of stress-corrosion cracking. An in situ scanning vibrating electrode technique was shown to detect currents coming from growing stress corrosion cracks in dilute thiosulfate solutions at temperatures below 90/sup 0/C. The onset of the cracking was clearly indicted by rapid decreases in the potential. It was observed that small cracks, which had grown for a limited period, were not susceptible to reinitiation of the cracking process. The onset of cracking was clearly observable by marked decreases in the potential which continued to decrease if cracking remained active and increased when cracking stopped. At and above 200/sup 0/C there were no potential fluctuation indicative of the onset of stress-corrosion cracking. Small potential differences between platinum and stainless steel were observed demonstrating the presence of a single electrochemically reversible reaction determined the potential of all metals within the stainless steel autoclave, and thus masking the onset of cracking. The presence of only an iron-containing deposit on the platinum suggested that a sufficiently reversible redox couple was set up between deposited iron oxide and a soluble iron species in solution which dominated the potential of the stainless steel and the platinum.
Date: January 1, 1986
Creator: Isaacs, H.S.
Partner: UNT Libraries Government Documents Department

Homestake tracking spectrometer: a one-mile deep 1400-ton liquid-scintillation nucleon-decay detector

Description: We describe a proposed nucleon decay detector able to demonstrate the existence of nucleon decay for lifetimes up to 5 x 10/sup 32/ yr. The proposed instrument is a self-vetoed completely-active 1400-ton liquid scintillation Tracking Spectrometer to be located in the Homestake Mine at a depth of 4200 mwe, where the cosmic ray muon flux is only 1100/m/sup 2//yr, more than 10/sup 7/ times lower than the flux at the earth's surface. Based on computer simulations and laboratory measurements, the Tracking Spectrometer will have a spatial resolution of +- 15 cm (0.32 radiation lengths); energy resolution of +- 4.2%; and time resolution of +-1.3 ns. Because liquid scintillator responds to total ionization energy, all neutrinoless nucleon decay modes will produce a sharp (+- 4.2%) total energy peak at approximately 938 MeV, thereby allowing clear separation of nucleon decay events from atmospheric neutrino and other backgrounds. The instrument will be about equally sensitive to most nucleon decay modes. It will be able to identify most of the likely decay modes (including n ..-->.. ..nu.. + K/sub s//sup 0/ as suggested by supersymmetric grand unified theories), as well as determine the charge of lepton secondaries and the polarization of secondary muons.
Date: January 1, 1982
Creator: Cherry, M.L.; Davidson, I.; Lande, K.; Lee, C.K.; Marshall, E.; Steinberg, R.I. et al.
Partner: UNT Libraries Government Documents Department

Validation issues: a view from the trenches

Description: Most papers on model evaluation or assessment dealing with verification and validation discuss means and mechanisms by which outside parties can perform peer review to provide verification and establish the validity of models. Little attention is paid to activities performed by the user-modeling team itself to improve the ability of the model to provide information useful in the decision-making process, and to provide confidence that the information is meaningful. This paper presents a number of case histories describing the authors' experience with this type of model improvement activity, called internal validation. They have been convinced that internal validation schemes should be incorporated in the project description and that they be used in part to answer questions of formulation. They further recommend that modelers incorporate sufficient funding in their project plans to carry out this function.
Date: January 1, 1979
Creator: Marcuse, W.; Pilati, D. & Sparrow, T.
Partner: UNT Libraries Government Documents Department

Toward a risk assessment of the spent fuel and high-level nuclear waste disposal system. Risk assessment requirements, literature review, methods evaluation: an interim report

Description: This report provides background information for a risk assessment of the disposal system for spent nuclear fuel and high-level radioactive waste (HLW). It contains a literature review, a survey of the statutory requirements for risk assessment, and a preliminary evaluation of methods. The literature review outlines the state of knowledge of risk assessment and accident consequence analysis in the nuclear fuel cycle and its applicability to spent fuel and HLW disposal. The survey of statutory requirements determines the extent to which risk assessment may be needed in development of the waste-disposal system. The evaluation of methods reviews and evaluates merits and applicabilities of alternative methods for assessing risks and relates them to the problems of spent fuel and HLW disposal. 99 refs.
Date: April 1, 1986
Creator: Hamilton, L.D.; Hill, D.; Rowe, M.D. & Stern, E.
Partner: UNT Libraries Government Documents Department

Experimental areas: summary of activity

Description: Participants were divided into two subgroups: a group to examine the large magnetic facilities and their impact on the design of the so-called facility halls, and a nonfacilities group that studied each of the other interaction regions. This latter group considered, in a time-ordered sequence dictated by the proposed construction schedule, topics associated with the wide-angle hall, open areas, and the small-angle hall. Although these divisions served to define the emphasis of the two subgroups, both sections also considered problems of a more general nature which are relevant, in principle, to all interaction regions. For example, the nonfacilities group discussed the needs for radiation shielding, different modes of beam dumping, requirements for interaction region vacuum chambers, etc., while the facilities group considered the effects of magnetic fields on the beams, the problem of access to central detectors, and the question of experiment mobility. Such topics are grouped under the vague heading General Considerations. Also included, as Appendices, are three BNL technical notes that relate directly to several of the topics studied and were used as source material in many of the discussion groups.
Date: January 1, 1978
Creator: Pope, B.G. & Stevens, A.J.
Partner: UNT Libraries Government Documents Department

Fate of accreting white dwarfs: Type I supernovae vs collapse

Description: The final fate of accreting C + O white dwarfs is either thermonuclear explosion or collapse, if the white dwarf mass grows to the Chandrasekhar mass. We discuss how the fate depends on the initial mass, age, composition of the white dwarf and the mass accretion rate. Relatively fast accretion leads to a carbon deflagration at low central density that gives rise to a Type Ia supernova. Slower accretion induces a helium detonation that could be observed as a Type Ib supernova. If the initial mass of the C + O white dwarf is larger than 1.2 Msub solar, a carbon deflagration starts at high central density and induces a collapse of the white dwarf to form a neutron star. We examine the critical condition for which a carbon deflagration leads to collapse, not explosion. For the case of explosion, we discuss to what extent the nucleosynthesis models are consistent with spectra of Type Ia and Ib supernovae. 61 refs., 18 figs.
Date: January 1, 1986
Creator: Nomoto, Ken'ichi
Partner: UNT Libraries Government Documents Department

High-level radioactive wste management: a means to social consensus

Description: The problem of safely disposing of high-level radioactive waste is not new, but it is becoming more pressing as the temporary storage facilities of public utilities run out. The technical questions of how best to immobilize these wastes for many centuries have been studied for years and many feel that these problems are solved, or nearly so. Many states have set up roadblocks to the federal waste management program, however, and it is clear that social consensus must be reached for any waste disposal program to be successful. The Nuclear Waste Policy Act of 1982 provides a long-needed framework for reaching this consensus, giving the states unprecedented access to federal decision-making. The rights of the states in a process of cooperation and consultation are clearly defined by the Act, but the means by which the states exercise those rights are left entirely to them. We examine the structures, methods, and goals open to the states, and recommend a rationale for the state decision process defining the roles of the governor and legislature.
Date: January 1, 1983
Creator: Pierce, B.; Hill, D. & Haefele, E.T.
Partner: UNT Libraries Government Documents Department

Zone approaches to international safeguards of a nuclear fuel cycle

Description: At present the IAEA designs its safeguards approach with regard to each type of nuclear facility so that the safeguards activities and effort are essentially the same for a given type and size of nuclear facility wherever it may be located. Conclusions regarding a state are derived by combining the results of safeguards verifications for the individual facilities within it. We have examined safeguards approaches for a state nuclear fuel cycle that take into account the existence of all of the nuclear facilities in the state. We have focussed on the fresh-fuel zone of an advanced nuclear fuel cycle, the several facilities of which use or process low-enriched uranium. At one extreme, flows and inventories would be verified at each material balance area. At the other extreme, the flows into and out of the zone and the inventory of the whole zone would be verified. The intention is to develop an approach which will make it possible to compare the technical effectiveness and the inspection effort for the facility-oriented approach, for the zone approach and for some reasonable intermediate safeguards approaches. Technical effectiveness, in these cases, means an estimate of the assurance that all nuclear material has been accounted for.
Date: January 1, 1986
Creator: Fishbone, L.G. & Higinbotham, W.A.
Partner: UNT Libraries Government Documents Department

Cost reductions in absorption chillers. Final report, June 1984-May 1985

Description: Absorption chillers have great difficulty competing with the electric-driven compression alternative, due in part to modest operating efficiencies and largely to high first costs. This project is an assessment of the possibility of lowering the costs of absorption chillers dramatically by the use of low material intensity in the design of a new generation of these machines. Breakeven costs for absorption chillers, their heat exchangers and heat exchanger materials were established which will allow commercial success. Polymeric and metallic materials appropriate to particular components and which meet the cost goals were identified. A subset of these materials were tested and ordered by success in tolerating conditions and materials found in absorption chiller applications. Conceptual designs which indicate the practicality of the low material intensity approach were developed. The work reported here indicates that there is a high probability that this apporach will be successful.
Date: May 1, 1986
Creator: Leigh, R.W.
Partner: UNT Libraries Government Documents Department

An x-ray microprobe beam line for trace element analysis

Description: The application of synchrotron radiation to an x-ray microprobe for trace element analysis is a complementary and natural extension of existing microprobe techniques using electrons, protons, and heavier ions as excitation sources for x-ray fluorescence. The ability to focus charged particles leads to electron microprobes with spatial resolutions in the sub-micrometer range and down to 100 ppM detection limits and proton microprobes with micrometer resolution and ppM detection limits. The characteristics of synchrotron radiation that prove useful for microprobe analysis include a broad and continuous energy spectrum, a relatively small amount of radiation damage compared to that deposited by charged particles, a highly polarized source which reduces background scattered radiation in an appropriate counting geometry, and a small vertical divergence angle of approx.0.2 mrad which allows for focussing of the light beam into a small spot with high flux. The features of a dedicated x-ray microprobe beam line developed at the National Synchrotron Light Source (NSLS) are described. 4 refs., 3 figs.
Date: January 1, 1987
Creator: Gordon, B.M.; Hanson, A.L.; Jones, K.W.; Kwiatek, W.M.; Long, G.J.; Pounds, J.G. et al.
Partner: UNT Libraries Government Documents Department

Neutron star formation in theoretical supernovae. Low mass stars and white dwarfs

Description: The presupernova evolution of stars that form semi-degenerate or strongly degenerate O + Ne + Mg cores is discussed. For the 10 to 13 Msub solar stars, behavior of off-center neon flashes is crucial. The 8 to 10 m/sub solar stars do not ignite neon and eventually collapse due to electron captures. Properties of supernova explosions and neutron stars expected from these low mass progenitors are compared with the Crab nebula. The conditions for which neutron stars form from accretion-induced collapse of white dwarfs in clsoe binary systems is also examined.
Date: January 1, 1986
Creator: Nomoto, K.
Partner: UNT Libraries Government Documents Department