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Octupole correlations in the heavy elements

Description: The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 2/sup 6/-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab.
Date: January 1, 1986
Creator: Chasman, R.R.
Partner: UNT Libraries Government Documents Department

Relativistic models in nuclear and particle physics

Description: A comparative overview is presented of different approaches to the construction of phenomenological dynamical models that respect basic principles of quantum theory and relativity. Wave functions defined as matrix elements of products of field operators on one hand and wave functions that are defined as representatives of state vectors in model Hilbert spaces are related differently to observables and dynamical models for these wave functions have each distinct advantages and disadvantages 34 refs.
Date: January 1, 1988
Creator: Coester, F.
Partner: UNT Libraries Government Documents Department

Application of high temperature ceramic superconductors (CSC) to commercial tokamak reactors

Description: Ceramic superconductors operating near liquid nitrogen temperature may experience higher heating rates without losing stability, compared to conventional superconductors. This will permit cable design with less stabilizer, reducing fabrication costs for large fusion magnets. Magnet performance is studied for different operating current densities in the superconductor, and cost benefits to commercial tokamak reactors are estimated. It appears that 10 kA . cm/sup -2/ (at 77 K and approx.10 T) is a target current density which must be achieved in order for the ceramic superconductors to compete with conventional materials. At current densities around 50 kA . cm/sup -2/ most potential benefits have already been gained, as magnet structural steel begins to dominate the cost at this point. For a steady state reactor reductions of approx.7% are forecast for the overall capital cost of the power plant in the best case. An additional approx.3% cost saving is possible for pulsed tokamaks. 9 refs., 4 figs., 8 tabs.
Date: October 1, 1987
Creator: Ehst, D.A.; Kim, S.; Gohar, Y.; Turner, L.; Smith, D.L. & Mattas, R.
Partner: UNT Libraries Government Documents Department

Effect of cross-sectional buckling on the behavior of ACS support columns

Description: These analyses of the performance of the support columns for the above-core structures (ACS) have two principal aims: (1) to predict the forces exerted by the column in a hypothetical core-disruptive accident (HCDA) so that the motion of the ACS can be predicted in a coupled fluid-structure analysis, (2) to provide the strains and deformations of the columns so that situations which lead to complete failure of the support system can be identified. In previous studies, the columns were represented by beam elements so changes in the cross section could not be treated. While the columns in many designs are relatively thick-walled, scale-model tests performed at SRI indicate significant changes in the cross section. Therefore, models have been developed in which the portions of the column which undergo significant changes in cross section are modeled by plate elements. For the purpose of comparing the plate-beam models in the context of the loads expected in an HCDA, its predictions were compared to experimental results obtained in the SRI scale model tests. The solutions were obtained by the code SAFE/RAS; a new plate element was added to that program to perform these studies.
Date: January 1, 1983
Creator: Kennedy, J.M. & Belytschko, T.B.
Partner: UNT Libraries Government Documents Department

EMC effect

Description: A review is presented of data and theoretical interpretations of the nuclear dependence of quark and antiquark distributions as observed in the deep inelastic scattering of neutrinos and charged leptons from nuclei. After a summary of the experimental situation and a survey of the broad spectrum of proposed explanations, I concentrate on the Q/sup 2/-rescaling approach and on interpretations in terms of conventional nuclear physics. The review concludes with a list of desirable future experiments. 31 refs., 4 figs.
Date: June 1, 1986
Creator: Berger, E.L.
Partner: UNT Libraries Government Documents Department

Evaluation of methods for leak detection in reactor primary systems and NDE of cast stainless steel

Description: Six cracks, including two field-induced IGSCC specimens and two thermal-fatigue cracks, have been installed in a laboratory acoustic leak detection facility. The IGSCC specimens produce stronger acoustic signals than the thermal-fatigue cracks at equivalent leak rates. Despite significant differences in crack geometry, the acoustic signals from the two IGSCC specimens, tested at the same leak rate, are virtually identical in the frequency range from 200 to 400 kHz. Thus, the quantitative correlations between the acoustic signals and leak rate in the 300 to 400 kHz band are very similar for the two IGSCC specimens. Also, acoustic background data have been acquired during a hot functional sensitivity of acoustic leak detection techniques. In addition, cross-correlation techniques have been successfully used in the laboratory to locate the source of an electronically simulated leak signal.
Date: January 1, 1984
Creator: Kupperman, D.S.; Claytor, T.N.; Prine, D.W. & Mathieson, T.A.
Partner: UNT Libraries Government Documents Department

Evaluation of molten lead mixing in sodium coolant by diffusion for application to PAHR. [LMFBR]

Description: In post-accident heat removal (PAHR) applications the use of a lead slab is being considered for protecting a porous bed of steel shots in ex-vessel cavity from direct impingement of molten steel or fuel upon vessel failure following a hypothetical core dissembly accident in an LMFBR. The porous bed is provided to increase coolability of the fuel debris by the sodium coolant. The objectives of the present study are (1) to determine melting rates of lead slabs of various thicknesses in contact with sodium coolant and (2) to evaluate the extent of penetration and mixing rates of molten lead into sodium coolant by molecular diffusion alone.
Date: January 1, 1983
Creator: Chawla, T.C.; Pedersen, D.R.; Leaf, G. & Minkowycz, W.J.
Partner: UNT Libraries Government Documents Department

Development of acoustic flow instruments for solid/gas pipe flows

Description: Two nonintrusive acoustic flow sensing techniques are reported. One technique, passive in nature, simply measures the bandpassed acoustic noise level produced by particle/particle and particle/wall collisions. The noise levels, given in true RMS voltages or in autocorrelations, show a linear relationship to particle velocity but increase with solid concentration. Therefore, the passive technique requires calibration and a separate measure of solid concentration before it can be used to monitor the particle velocity. The second technique is based on the active cross-correlation principle. It measures particle velocity directly by correlating flow-related signatures at two sensing stations. The velocity data obtained by this technique are compared with measurements by a radioactive-particle time-of-flight (TOF) method. A multiplier of 1.53 is required to bring the acoustic data into agreement with the radioactive TOF result. The difference may originate from the difference in flow fields where particles are detected. The radioactive method senses particles mainly in the turbulent region and essentially measures average particle velocity across the pipe, while the acoustic technique detects particles near the pipe wall, and so measures the particle velocity in the viscous sublayer. Both techniques were tested in flows of limestone and air and 1-mm glass beads and air at the Argonne National Laboratory Solid/Gas Test Facility (SGFTF). The test matrix covered solid velocities of 20 to 30 m/s in a 2-in. pipe and solid-to-gas loading ratios of 6 to 22. 37 refs., 19 figs., 4 tabs.
Date: May 1, 1986
Creator: Sheen, S.H. & Raptis, A.C.
Partner: UNT Libraries Government Documents Department

Development of an array of cooled large area Si(Li) detectors

Description: A system containing six cooled, 34 mm diam by 7 mm thick, high-resolution Si(Li) detectors designed to maximize the sensitivity for counting x rays in the 10-30 keV range to measure trace radionuclides in soil samples has been successfully fabricated. The detectors were mounted in a paddle-shaped cryostat with a single large beryllium window on each side. This configuration provides for efficient anticoincidence background suppression and effectively doubles the sensitive detector area because x rays can impinge on the detectors from both sides. To maximize detection efficiency, the thickness of the cryostat was held to a bare minimum (25 mm); this caused severe difficulties during fabrication of the system. Cutting down the rim of the detectors reduced to an acceptable level the microphony caused by movement of the beryllium window that faces the lithium-diffused contact of the detectors. Since this system will be used for low level counting. careful testing was performed to select materials having the lowest radioactivity.
Date: October 1, 1985
Creator: Pehl, R.H.; Madden, N.W.; Walton, J.T.; Malone, D.F.; Landis, D.A.; Goulding, F.S. et al.
Partner: UNT Libraries Government Documents Department

Diffractive hard scattering

Description: I discuss events in high energy hadron collisions that contain a hard scattering, in the sense that very heavy quarks or high P/sub T/ jets are produced, yet are diffractive, in the sense that one of the incident hadrons is scattered with only a small energy loss. 8 refs.
Date: March 1, 1986
Creator: Berger, E.L.; Collins, J.C.; Soper, D.E. & Sterman, G.
Partner: UNT Libraries Government Documents Department

Bombardment-induced segregation and redistribution

Description: During ion bombardment, a number of processes can alter the compositional distribution and microstructure in near-surface regions of alloys. The relative importance of each process depends principally on the target composition, temperature, and ion characteristics. In addition to displacement mixing leading to a randomization of atomic locations, and preferential loss of alloying elements by sputtering, which are dominant at relatively low temperatures, several thermally-activated processes, including radiation-enhanced diffusion, radiation-induced segregation and Gibbsian adsorption, also play important roles. At elevated temperatures, nonequilibrium point defects induced by ion impacts become mobile and tend to anneal out by recombination and diffusion to extended sinks, such as dislocations, grain boundaries and free surfaces. The high defect concentrations, far exceeding the thermodynamic equilbrium values, can enhance diffusion-controlled processes, while persistent defect fluxes, originating from the spatial non-uniformity in defect production and annihilation, give rise to local redistribution of alloy constituents because of radiation-induced segregation. Moreover, when the alloy is maintained at high temperature, Gibbsian adsorption, driven by the reduction in free energy of the system, occurs even without irradiation; it involves a compositional perturbation in a few atom layers near the alloy surface. The combination of these processes leads to the complex development of a compositionally-modified layer in the subsurface region. In the present paper, selected examples of these different phenomena and their synergistic effects on the evolution of the near-surface compositions of alloys during sputtering and ion implantation at elevated temperatures are discussed. 74 refs., 7 figs., 1 tab.
Date: April 1, 1986
Creator: Lam, N.Q. & Wiedersich, H.
Partner: UNT Libraries Government Documents Department

Boilup transients in a closed system. [LMFBR]

Description: In analysis of certain hypothetical LMFBR accidents, it is often postulated that the core undergoes a gradual disruption leading to a boiling mixture of molten fuel and steel confined within the original core volume. The boilup behavior of such a fuel/steel mixture is an important consideration in assessing the potential for recriticalities. An experimental program is underway at ANL in order to provide a phenomenological understanding of the boilup behavior. The experiment is being conducted in a five-liter pressure vessel in which a pool of de-mineralized water is heated by volumetrically spaced electrical resistance heaters. This paper discusses the results of transient tests on pool boilup response to varying condensation rates at the upper boundary.
Date: January 1, 1983
Creator: Cho, D.H.; Lambert, G.A. & Chan, S.H.
Partner: UNT Libraries Government Documents Department

Acoustic leak detection and ultrasonic crack detection

Description: A program is under way to assess the effectiveness of current and proposed techniques for acoustic leak detection (ALD) in reactor coolant systems. An ALD facility has been constructed and tests have begun on five laboratory-grown cracks (three fatigue and two thermal-fatigue and two field-induced IGSCC specimens. After ultrasonic testing revealed cracks in the Georgia Power Co. HATCH-1 BWR recirculation header, the utility installed an ALD system. Data from HATCH-1 have given an indication of the background noise level at a BWR recirculation header sweepolet weld. The HATCH leak detection system was tested to determine the sensitivity and dynamic range. Other background data have been acquired at the Watts Bar Nuclear Reactor in Tennessee. An ANL waveguide system, including transducer and electronics, was installed and tested on an accumulator safety injection pipe. The possibility of using ultrasonic wave scattering patterns to discriminate between IGSCCs and geometric reflectors has been explored. Thirteen reflectors (field IGSCCs, graphite wool IGSCCs, weld roots, and slits) were examined. Work with cast stainless steel (SS) included sound velocity and attenuation in isotropic and anisotropic cast SS. Reducing anisotropy does not help reduce attenuation in large-grained material. Large artificial flaws (e.g., a 1-cm-deep notch with a 4-cm path) could not be detected in isotropic centrifugally cast SS (1 to 2-mm grains) by longitudinal or shear waves at frequencies of 1 MHz or greater, but could be detected with 0.5-MHz shear waves. 13 figures.
Date: October 1, 1983
Creator: Kupperman, D.S.; Claytor, T.N. & Groenwald, R.
Partner: UNT Libraries Government Documents Department

Be(d,n) source at a modest facility

Description: Source characterization for deuteron energies less than 8 MeV is discussed including: intensity, spectrum and angular distributions. Pulsed and steady-state applications of the source to the acquisition of fast-neutron data are illustrated by energy-averaged neutron total cross-section and spectrum-averaged activation cross-section measurements. Source utilization, measurement techniques, and experimental results are described with attention to self-shielding effects, background suppression and specification of uncertainties. These illustrations are extrapolated to broader-scope studies, taking advantage of the high fact-neutron intensities. The present and future potential is determined more by detection capability than by source properties. 19 refs., 9 figs.
Date: January 1, 1986
Creator: Smith, A.B.; Smith, D.L. & Whalen, J.F.
Partner: UNT Libraries Government Documents Department

Domestic and personal determinants of the contamination of individuals by household radon daughters

Description: Radon daughters were counted by gamma spectroscopy from 180 adult residents of eastern Pennsylvania during the winter of 1983-84. Body radon daughter contamination is an index of relative individual respiratory exposures to radon daughters. These can be related to household radon levels, and to personal risk factors such as sex and tobacco smoking. Over 75% of this Pennsylvania population appeared to have environmentally enhanced radon daughter contamination; 59% had counting rates greater than 2 s.d. above background. House radon levels were the major determinants of radon daughters contamination in the 112 subjects for which both sets of measurements were available (p<.001). Both sex (<.02) and cigarette smoking (p<.005) were found to significantly modify that relationship, after nonlinear adjustment for travel times. Using a logarithmic model, for a given radon level body contamination by radon daughters in females was 2-3.5x higher than in males. Nonsmokers had 2-4x higher levels of contamination than smokers. For female nonsmokers relative to male smokers (which in general corresponds to the population of major concern relative to the population from which risk estimates have been derived), the excesses multiply. These results are for total contamination, both internal and external.
Date: January 1, 1986
Creator: Stebbings, J.H.; Kardatzke, D.R.; Toohey, R.E.; Essling, M.E. & Pagnamenta, A.
Partner: UNT Libraries Government Documents Department

Argonne National Laboratory, High Energy Physics Division: Semiannual report of research activities, July 1, 1986-December 31, 1986

Description: This paper discusses the research activity of the High Energy Physics Division at the Argonne National Laboratory for the period, July 1986-December 1986. Some of the topics included in this report are: high resolution spectrometers, computational physics, spin physics, string theories, lattice gauge theory, proton decay, symmetry breaking, heavy flavor production, massive lepton pair production, collider physics, field theories, proton sources, and facility development. (LSP)
Date: January 1, 1987
Partner: UNT Libraries Government Documents Department

Preliminary radiation dose assessment for the Palmerton ore storage site, Palmerton, Pennsylvania

Description: Potential maximum radiation doses rates were calculated for the Palmerton ore storage site in Palmerton, Pennsylvania. The RESRAD computer code, which implements the methodology described in the US Department of Energy's manual for establishing residual radioactive material guidelines, was used in this evaluation. Four potential scenarios were considered for the Palmerton ore storage site. Two scenarios were developed on the basis of industrial use of the site, and two were developed on the basis of residential use of the site. The scenarios also vary with regard to time spent at the site, sources of food consumed, and source terms. The RESRAD code was used to analyze potential radiation doses from three exposure pathways. The results indicate that the basic dose limit of 100 mrem/yr would not be exceeded in Scenarios A (industrial use, hot spot), B (industrial use, homogenous contamination), and C (residential use, homogenous contamination), but would be exceeded in Scenario D (residential use, hot spot). The potential maximum dose rates for Scenarios A, B, C, and D are 1.0 mrem/yr, 0.66 mrem/yr, and 360 mrem/yr, respectively. 3 refs., 3 tabs.
Date: February 1, 1991
Creator: Nimmagadda, M. & Yu, C.
Partner: UNT Libraries Government Documents Department

KAOS/LIB-V: A library of nuclear response functions generated by KAOS-V code from ENDF/B-V and other data files

Description: KAOS/LIB-V: A library of processed nuclear responses for neutronics analyses of nuclear systems has been generated. The library was prepared using the KAOS-V code and nuclear data from ENDF/B-V. The library includes kerma (kinetic energy released in materials) factors and other nuclear response functions for all materials presently of interest in fusion and fission applications for 43 nonfissionable and 15 fissionable isotopes and elements. The nuclear response functions include gas production and tritium-breeding functions, and all important reaction cross sections. KAOS/LIB-V employs the VITAMIN-E weighting function and energy group structure of 174 neutron groups. Auxiliary nuclear data bases, e.g., the Japanese evaluated nuclear data library JENDL-2 were used as a source of isotopic cross sections when these data are not provided in ENDF/B-V files for a natural element. These are needed mainly to estimate average quantities such as effective Q-values for the natural element. This analysis of local energy deposition was instrumental in detecting and understanding energy balance deficiencies and other problems in the ENDF/B-V data. Pertinent information about the library and a graphical display of the main nuclear response functions for all materials in the library are given. 35 refs.
Date: April 1, 1989
Creator: Farawila, Y.; Gohar, Y. & Maynard, C.
Partner: UNT Libraries Government Documents Department

Influences of thermal spikes in ion beam mixing

Description: Guided by the results of molecular dynamics simulations, we develop a thermal spike model for the relaxation of collision cascades in which the hot zone has mobile, reacting defects and cools by thermal diffusion. Marker atoms within such spikes are taken to migrate by radiation enhanced diffusion which is governed by the locally transient temperatures and defect concentrations. The atomic mixing associated with such motions is examined, on the basis of the model, for a variety of ion-target systems. The dependences of spike mixing on diffusion mechanism, irradiation ion and energy, and sample temperature are discussed. 11 references, 4 figures, 1 table.
Date: October 1, 1984
Creator: Peak, D. & Averback, R.S.
Partner: UNT Libraries Government Documents Department

Search for free quarks at PEP

Description: The results of a search for fractionally charged particles produced in e/sup +/e/sup -/ annihilation at 29 GeV/c/sup 2/ are discussed. Results from cosmic-ray searches for fractionally charged particles, tachyons, and massive particles using the same detector are also presented.
Date: January 1, 1982
Creator: Freedman, S.J.
Partner: UNT Libraries Government Documents Department

Analysis of the burping behavior of the cold solid methane moderator at IPNS (Intense Pulsed Neutron Source)

Description: Examination of the cold solid methane moderator at IPNS (Model II) revealed that a circumferential weld failed due to high internal pressure, such as would be caused by thermal expansion of solid methane or the release of Hydrogen gas upon spontaneous heating. This weld is the main object of current attention for a design of a replacement. The present paper deals with the processes which lead to the burping behavior and outlines the analysis of some of the consequences. The purpose is to determine conditions under which the system can operate at the lowest possible temperature, avoiding the problems experienced to data.
Date: January 1, 1986
Creator: Carpenter, J.M. & Walter, U.
Partner: UNT Libraries Government Documents Department

Magnetic monopoles and dipoles in quantum mechanics

Description: The force on and the energy of a ''di-monopole'', which is the limiting case of a dipole made from two monopoles at zero separation and finite magnetic moment, interacting with an externally fixed magnetic field resulting from an electric current, is considered. A model involving only a monopole is used to illustrate the physical principles involved when magnetic sources move in a solenoidal field whose source is an electric current. The problems encountered in Hamiltonian theory are discussed. 5 refs., 3 figs. (LEW)
Date: January 1, 1986
Creator: Lipkin, H.J. & Peshkin, M.
Partner: UNT Libraries Government Documents Department

Anelastic relaxation in irradiated Cu-Be

Description: Ultrasonic velocity measurements were made after thermal neutron irradiation of single-crystal Cu specimens containing 700 or 3700 appM Be. Ultrasonic attenuation was measured in similar specimens after 3 MeV electron irradiation. Three anelastic relaxation processes due to self-interstitial-Be complexes were observed. Cu-Be 1 was found to occur near liquid helium temperature; the temperature dependence of the velocity change suggests that reorientation of the Cu-Be 1 complex may involve quantum mechanical tunneling. Cu-Be produced an attenuation peak at approx.2.5 K at a frequency of 10 MHz. Cu-Be 3 appeared simultaneously with 2 as a shoulder on the high temperature side of the 2.5 K attenuation peak.
Date: May 1, 1985
Creator: Rehn, L.E.; Wiedersich, H. & Granato, A.V.
Partner: UNT Libraries Government Documents Department

Tracer diffusion of /sup 60/Co and /sup 63/Ni in amorphous NiZr alloy

Description: Tracer diffusion of /sup 60/Co and /sup 63/Ni in equiatomic amorphous NiZr alloy in the temperature range between 486 and 641/sup 0/K can be described by: D/sub Co/sup */ = 3.7 x 10/sup -7/ exp(-(135 +- 14) kJ mole/sup -1//RT) m/sup 2//sec and D/sub Ni//sup */ = 1.7 x 10/sup -7/ exp(-(140 +- 9) kJ mole/sup -1//RT) m/sup 2//sec. The values of D/sub Ni//sup */ are in reasonable agreement with those measured by the Rutherford backscattering technique. The measured diffusivities were independent of time, indicating that no relaxation took place during diffusion. 27 refs., 2 tabs.
Date: January 1, 1987
Creator: Hoshino, K.; Averback, R.S.; Hahn, H. & Rothman, S.J.
Partner: UNT Libraries Government Documents Department