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HSST wide-plate test results and analysis

Description: Fifteen wide-plate crack-arrest tests have been completed to date, ten utilizing specimens fabricated from A533B class 1 material (WP-1 and WP-CE series), and five fabricated from a low upper-shelf base material (WP-2 series). Each test utilized a single-edge notched specimen that was subjected to a linear thermal gradient along the plane of crack propagation. Test results exhibit an increase in crack-arrest toughness with temperature, with the rate of increase becoming greater as the temperature increases. When the wide-plate test results are combined with other large-specimen results the data show a consistent trend in which the K/sub Ia/ data extends above the limit provided in ASME Section XI. 24 refs., 11 figs., 7 tabs.
Date: January 1, 1988
Creator: Naus, D.J.; Bass, B.R.; Keeney-Walker, J.; Fields, R.J.; deWit, R. & Low, S.R. III
Partner: UNT Libraries Government Documents Department

A high-density, high-temperature mixture model

Description: This paper describes a model designed for multicomponent systems. The model is useful for high temperature and high pressures. (WRF)
Date: March 1, 1988
Creator: Ree, F.H.
Partner: UNT Libraries Government Documents Department

Time-dependent mass loss from hot stars with and without radiative driving

Description: A numerical hydrodynamics code is used to investigate two aspects of the winds of hot stars. The first is the question of the instability of the massive radiatively-driven wind of an O star that is caused by the line shape mechanism: modulation of the radiation force by velocity fluctuations. The evolution of this instability is studied in a model O star wind, and is found, /ital modulo/ some numerical uncertainty, to lead to wave structures that are compatible with observations of wind instabilities. The other area of investigation is of main-sequence B star winds. Attempts were made to simulate a radiatively-driven and a pulsation-driven wind in a B star, but in each case the wind turned out to be very weak. It is argued that the pulsation-driven wind model is not likely to apply to B stars. 28 refs., 11 figs.
Date: January 29, 1988
Creator: Castor, J.I.; Owocki, S.P. & Rybicki, G.B.
Partner: UNT Libraries Government Documents Department

Some effects of non-condensible gas in geothermal reservoirs with steam-water counterflow

Description: A mathematical model is developed for fluid and heat flow in two-phase geothermal reservoirs containing non-condensible gas (CO{sub 2}). Vertical profiles of temperature, pressures and phase saturations in steady-state conditions are obtained by numerically integrating the coupled ordinary differential equations describing conservation of water, CO{sub 2}, and energy. Solutions including binary diffusion effects in the gas phase are generated for cases with net mass throughflow as well as for balanced liquid-vapor counterflow. Calculated examples illustrate some fundamental characteristics of two-phase heat transmission systems with non-condensible gas. 14 refs., 3 figs.
Date: January 1, 1988
Creator: McKibbin, R. & Pruess, K.
Partner: UNT Libraries Government Documents Department

The electronic structure of condensed molecular systems

Description: We have reviewed some of the basic properties of the electronic structure of condensed molecular systems. For the rare-gas solids, we concentrated our discussion on changes in the ground- and excited-state crystal-atomic wave functions as calculated with an approximate theoretical method. Compression of these wave functions leads to a softening of the equation of state at high densities, which seems to account for much of the total many-body effects. This compression is a true many-body effect and cannot be easily decomposable into a sum of 3-body and higher terms. We reviewed the electronic properties of four molecular systems, each manifesting different behavior at high densities. Because of a general lack of theory of the electronic structure of molecular solids, we restricted ourselves to a descriptive account. Solid oxygen, for instance, seems to exhibit the beginnings of covalent bonding between the ..pi..* orbitals on adjacent molecules in its epsilon phase. It was a combination of optical-absorption data and infrared and Raman spectroscopy that led to these conclusions. Iodine is unique in that it becomes metallic as a molecular crystal at pressures easily obtainable experimentally. It is interesting that the x-ray data, which indicates a transition to a monatomic lattice at 21 GPa, and the Moessbauer spectra, which implies that molecular character is retained to 30 GPa, are in such disagreement. The next system discussed, solid acetylene, is a nice example of high-pressure polymerization and study of this system should shed light on the polymerization of more complicated systems. Finally, we briefly discussed the predicted dissociation of solid molecular nitrogen at high pressures. Here, theory has made a prediction and experiment has disproven it. Molecular systems show a diverse range of behavior in electronic structures at high pressures, from metallization to chemistry; theory is lagging. 68 refs., 10 figs.
Date: January 1, 1988
Creator: LeSar, R.A.
Partner: UNT Libraries Government Documents Department

Freely expanding detonation products: Scaling of rate processes

Description: Using the Los Alamos reactive hydrodynamics code KIVA, calculations have been made to simulate the free expansion of cylinders of detonation products into a high vacuum. The emphasis of this paper is on the scaling of rate processes with cylinder size and initial conditions as a function of position in the expanding mass. The processes considered include diffusion, unimolecular decomposition, biomolecular radical reactions, and vibrational relaxation. The calculations also give time-dependent velocity fields; schlieren images; and profiles of density, pressure, and temperature. Many features of the calculations can be compared with experimental observations, including time-delayed schlieren and shadowgraph snapshots, time-dependent absorption spectra, and time-of-arrival profiles of molecular species. Some unexpected insights, such as the effect of the equation of state on the shape of the expanding plume and the effect of position on the rate of quenching, are discussed. These calculations are being used to interpret the available experimental data and to design future experiments. 6 refs., 13 figs.
Date: January 1, 1988
Creator: Greiner, N.R.
Partner: UNT Libraries Government Documents Department

Scaling of the magnetoresistance of UBe/sub 13/ under pressure

Description: We report magnetoresistance measurements of the heavy electron compound UBe/sub 13/ above the superconducting transition temperature T/sub c/ and below 4 K for pressures P up to 19 kbar and for magnetic fields H up to 9T. We observe strong negative magnetoresistance at all pressures and temperatures. The resistivity /rho/ is quadratic in temperature T from T/sub c/ up to a maximum temperature of 1 K at 1 bar increasing to 2 K at 19 kbar. The slope of the T/sup 2/ term decreases with both H and with P. We find that delta(H) /triple bond/ /minus/ (/rho/(H) /minus/ /rho/(0))/rho/(0) for a given pressure scales as a function of HT and exhibits power law behavior over one decade with an exponent of 1.7. In addition, delta(H) at high pressure shows this same power law over a more limited HT range. 16 refs., 5 figs.
Date: January 1, 1988
Creator: Willis, J.O.; McElfresh, M.W.; Thompson, J.D.; Smith, J.L. & Fish, Z.
Partner: UNT Libraries Government Documents Department

Preliminary report confined tension testing of 900-24

Description: A specially designed confining pressure vessel is described that allows tensile samples to be tested under a superimposed confining hydrostatic pressure. Tests on samples of well characterized materials such as aluminum were used to verify the operation of the system, calibration of the internal load cell, and data reduction methods. The results of a series of exploratory tests done on the inert material 900-24 are described. 4 refs., 17 figs., 2 tabs.
Date: September 10, 1988
Creator: Harlow, R.A. & Browning, R.V.
Partner: UNT Libraries Government Documents Department

Analysis of internal wellbore flow

Description: Most two-phase geothermal wells are located in fractured rocks and intersect a few major feedzones. It is well known that internal wellbore flow between feedzones often occurs during warmup or pressure recovery periods. The internal flow can occur even when the reservoir is initially in pressure equilibrium because of the different phase composition that develops within the wellbore. Internal flow can cause large apparent pressure drawdowns and significantly affect pressure and temperature surveys as well as pressure buildup tests. This paper presents an analytic method for using static pressure surveys to calculate internal flowrates between two zones when the reservoir characteristics are known. Conversely, the transmissivity of the feedzone with the lowest transmissivity can be calculated from measurements of internal flowrates and wellbore pressures. 3 refs., 6 figs.
Date: January 1, 1988
Creator: Ripperda, M. & Bodvarsson, G.S.
Partner: UNT Libraries Government Documents Department

A method for suppression of pressure pulses in fluid-filled piping: Theoretical analysis

Description: A simple, nondestructive method to suppress pressure pulses in a fluid-filled piping is theoretically analyzed, and the result provides the basis needed for design and evaluation of a pressure-pulse suppression device based on the proposed theory. The method is based on forming of fluid jets in the event of a pressure surge such that the pulse height as well as the energy of the pulse are reduced. The result for pressure pulses in the range of practical interest shows that a substantial reduction can be attained in the pulse height with accompanied reduction of pulse energy remaining in the system. The analysis also reveals that a certain amount of trade-off exists in the design of the suppression device; a certain level of pulse energy remaining in the system must be accepted in order to limit the pulse height below a certain level and vice versa. 7 refs., 5 figs.
Date: June 1, 1988
Creator: Shin, Y.W. & Wiedermann, A.H.
Partner: UNT Libraries Government Documents Department

Parametric modelling of temporal variations in radon concentrations in homes

Description: The /sup 222/Rn concentrations in the living area, the basement, and the undelying soil of a New Jersey home have been measured at half-hour intervals over the course of a year, as have indoor and outdoor temperatures, wind speed and direction, and indoor-outdoor and basement-subslab pressures; in addition, periods of furnace opration have been logged. We generalize and extend an existing radon entry model in order to demonstrate the dependence of the radon concentration on the environmental variales and the extent of furnace use. The model contains parameters which are dependent on geological and structural factors which have not been measured or otherwise determined; statistical methods are used to find the best values of the parameters. The non-linear regression of the model predictions (over time) on the measured living area radon concentrations yields an R)aup 2) of 0.88. 9 refs., 2 figs
Date: January 1, 1988
Creator: Revzan, K.L.; Turk, B.H.; Harrison, J.; Nero, A.V. & Sextro, R.G.
Partner: UNT Libraries Government Documents Department

Remote maintenance design activities and research and development accomplishments for the Compact Ignition Tokamak

Description: The use of deuterium-tritium (D-T) fuel for the Compact Ignition Tokamak (CIT) requires the use of remote handling technology to carry out maintenance operations. The remote operations consist of removing and replacing such components as first wall armor protection tiles, radio-frequency (rf) heating modules, and diagnostic modules. The major pieces of equipment being developed for maintenance activities internal to the vacuum vessel include an articulated boom manipulator (ABM), an inspection manipulator, and special tooling. For activities external to the vessel, the equipment includes a bridge-mounted manipulator system, decontamination equipment, hot cell equipment, and solid radiation-waste (rad-waste) handling and packaging equipment. The CIT Project is completing the conceptual design phase; research and development (R and D) activities, which include demonstrations of remote maintenance operations on full-size partial mock-ups are under way. 5 figs.
Date: January 1, 1988
Creator: Spampinato, P.T.
Partner: UNT Libraries Government Documents Department

The turbulent heat flux in low Mach number flows with large density variations

Description: A transport equation has been derived which is the difference between the volume- and mass-averaged velocities and is simply related to the turbulent heat flux phi/sup h/. Using this equation and an assumption analogous to the drift flux approximation of two-phase flow modeling, an algebraic closure relation for phi/sup h/ that exhibits fluxes due to directed transport proportional to -del anti p and due to gradient transport proportional to -del Tau has been obtained. Much work remains to be done before the model can be used in predictive calculations of low Mach number flows with large density variations. The transport equation involves an additional scalar b that is a measure of the density fluctuations. An equation for b must be derived and terms in it modeled. We hope to use the transport equation and b-equation in conjunction with a k - anti epsilon turbulence model. The k- and anti epsilon- equations must be reexamined to see that modifications are needed when the flows have large density variations. When mass transport is important, such as in many combustion problems, expressions for the turbulent mass flux must be developed.
Date: January 1, 1988
Creator: O'Rourke, P.J. & Collins, L.R.
Partner: UNT Libraries Government Documents Department

The effect of age on the structural integrity of HEPA filters

Description: All of the controls on high-efficiency particulate air (HEPA) filters are based on rigid manufacturing standards with regard to filtration efficiency, temperature performance, pressure integrity, and strength. Third-party inspection and testing by the US Department of Energy increases the reliability of new HEPA filters, but only routine in-place testing is used to assure that an aging filter performs adequately. In 1980 the Lawrence Livermore National Laboratory initiated a small evaluation to determine if age has a significant effect on the structural integrity of HEPA filters. A series of used uncontaminated filters dating back to 1965 was obtained for these tests. Tensile strength tests on the old media indicated a decrease in strength. To provide additional measurement of the filters' overall strength, several of these aged filters were subjected to pressure pulses equivalent to the NRC Region I tornado pulses and shock wave overpressures. Data from these tests indicate a decrease in breaking pressure of from 25/endash/50%. A large increase in complete filter pack blow-out during the simulated NRC Region I tornado tests was also observed. The preliminary results indicate the need for an administrative lifetime for HEPA filters used in critical nuclear facilities. Due to the unique conditions in each facility, different administrative lifetimes may be necessary.
Date: August 17, 1988
Creator: Johnson, J. S.; Beason, D. G.; Smith, P. R. & Gregory, W. S.
Partner: UNT Libraries Government Documents Department

Vacuum sorption pumping at cryogenic temperatures of argon and oxygen on molecular sieves

Description: Cryosorption pumping is a method of excavating enclosed volumes by adsorbing gas on a deep bed of solid sorbent (typically a zeolite) at cryogenic temperatures. Modeling the dynamic behavior of these systems for air pumping requires information on two major constituents of air, oxygen and argon, which had not been previously studied, as well as data on a nonadsorbing specie, helium. Deep beds of Davison 4A molecular sieves were subjected to a metered flow of pure gas and the pressure history of the experiment was monitored, using computer data acquisition techniques. Particle size variations is the major variable in determining the mechanism of the process. The data acquired in the current study compare favorably with previous experiments. Previously developed models for the dynamic sorption behavior of deep beds under vacuum for two extreme conditions, micropore and micropore control were tested in this study. The sorption behavior of argon clearly fit into the category of macropore controlled sorption, indicating that these species are adsorbed primarily on the surface of the zeolite crystals, much like the theoretical and experimental results for N/sub 2/ cryosorption on the same sieves of Crabb. On the other hand oxygen sorption is most likely micropore controlled, and may be molded by the method of Praznick. 11 refs., 7 figs., 1 tab.
Date: January 1, 1988
Creator: Perona, J.J.; Gibson, M.R. & Byers, C.H.
Partner: UNT Libraries Government Documents Department

Very high pressure Moessbauer spectroscopy using diamond anvil cells

Description: The technique of generating very high pressure by means of Diamond Anvil Cells (DAC) for Mossbauer Effect applications is outlined. A comprehensive description is presented of the principles of DAC, modification for the use in M/umlt o/ssbauer Spectroscopy (MS), the Merrill--Bassett and Bassett cells, of pressure measurements, of gasketing and collimation, and of hydrostatic media. Examples of /sup 151/Eu, /sup 119/Sn and /sup 129/I are given showing the feasibility of DAC applications in MS. Other isotopes with potential use for high pressure MS using DAC are suggested. 27 refs., 9 figs.
Date: January 1, 1988
Creator: Pasternak, M.P. & Taylor, R.D.
Partner: UNT Libraries Government Documents Department

Shock consolidation of YBa/sub 2/Cu/sub 3/O/sub 7-x/ powders

Description: Yttrium-Barium-Copper Oxide ceramics, commonly known as Y-123, have been shock compacted by numerous investigators. Unfortunately most of them, initially, had not succeeded in obtaining crack/melt-free monoliths. What is now known from these and similar efforts is that the shock pressure must be low and that the temperature excursion due to the shock and related strains be minimized and kept below the decomposition temperature of the Y-123 compound. This paper describes the efforts and considerations in some of the shock work performed at Los Alamos National Laboratory. 12 refs., 8 figs., 1 tab.
Date: January 1, 1988
Creator: Staudhammer, K.P.
Partner: UNT Libraries Government Documents Department

Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR (pressurized-water-reactor) plants

Description: Recent pressure-vessel surveillance data from the High Flux Isotope Reactor (HFIR) indicate an embrittlement fluence-rate effect that is applicable to the evaluation of the integrity of light-water reactor (LWR) pressure vessel supports. A preliminary evaluation using the HFIR data indicated increases in the nil ductility transition temperature at 32 effective full-power years (EFPY) of 100 to 130/degree/C for pressurized-water-reactor (PWR) vessel supports located in the cavity at midheight of the core. This result indicated a potential problem with regard to life expectancy. However, an accurate assessment required a detailed, specific-plant, fracture-mechanics analysis. After a survey and cursory evaluation of all LWR plants, two PWR plants that appeared to have a potential problem were selected. Results of the analyses indicate minimum critical flaw sizes small enough to be of concern before 32 EFPY. 24 refs., 16 figs., 7 tabs.
Date: January 1, 1988
Creator: Cheverton, R.D.; Pennell, W.E.; Robinson, G.C. & Nanstad, R.K.
Partner: UNT Libraries Government Documents Department

Crack arrest behavior of reactor pressure vessel steels at high temperatures

Description: The Heavy-Section Steel Technology Program at the Oak Ridge National Laboratory under the sponsorship of the US Nuclear Regulatory Commission is conducting experimental and analytical studies to improve the understanding of conditions that govern the initiation, rapid propagation, arrest and ductile tearing of cracks in reactor pressure vessel (RPV) steels. In support of this objective, large-scale wide-plate experiments are performed to generate crack-arrest toughness data for RPV steels at temperatures approaching and above the onset of Charpy upper-shelf behavior. Analytical studies are addressing the role of dynamics and nonlinear rate-dependent (i.e., viscoplastic) effects in the interpretation of crack run-arrest events in these ductile materials. A summary of the wide-plate tests performed to date is presented, including details of test procedures, test data, and results of analyses performed to date. The importance of incorporating viscoplastic effects into dynamic analysis of crack run-arrest events in these strain-rate sensitive steels is examined through applications of selected proposed viscoplastic constitutive equations and fracture parameters to the interpretation of data from the wide-plate tests. The crack-arrest data are compared with those from small ASTM-type specimens and other large structural tests.
Date: January 1, 1988
Creator: Pugh, C. E.; Naus, D. J. & Bass, B. R.
Partner: UNT Libraries Government Documents Department

Pressure broadening of the ((dt. mu. )dee)/sup */ formation resonances

Description: The treatment of ((dt..mu..)dee)/sup */ formation at high densities as a pressure broadening process is discussed. The quasistatic approximation is shown to satisfy the usual conditions of muon-catalyzed fusion better than does the impact approximation. Complete accurate results are shown for the impact approximation, and a preliminary rough treatment is presented to illustrate the quasistatic approximation. 13 refs., 8 figs.
Date: January 1, 1988
Creator: Cohen, J. S.; Leon, M. & Padial, N. T.
Partner: UNT Libraries Government Documents Department

Poloidal VV currents, disruption-induced VV forces, and TSC-EIGENCIRC interfaces

Description: This paper discusses the following topics: Poloidal vacuum vessel currents induced by toroidal flux changes; TSC disruption-induced forces on the CIT 2.10m vacuum vessel; status of EIGENCIRC-TSC interface; and TSC disruption run with external TF structure. 6 figs., 2 tabs. (LSP)
Date: January 1, 1988
Creator: Sayer, R.O.
Partner: UNT Libraries Government Documents Department

Tritium pellet injector results

Description: Injection of solid tritium pellets is considered to be the most promising way of fueling fusion reactors. The Tritium Proof-of- Principle (TPOP) experiment has demonstrated the feasibility of forming and accelerating tritium pellets. This injector is based on the pneumatic pipe-gun concept, in which pellets are formed in situ in the barrel and accelerated with high-pressure gas. This injector is ideal for tritium service because there are no moving parts inside the gun and because no excess tritium is required in the pellet production process. Removal of /sup 3/He from tritium to prevent blocking of the cryopumping action by the noncondensible gas has been demonstrated with a cryogenic separator. Pellet velocities of 1280 m/s have been achieved for 4-mm-diam by 4-mm-long cylindrical tritium pellets with hydrogen propellant at 6.96 MPa (1000 psi). 10 refs., 10 figs.
Date: January 1, 1988
Creator: Fisher, P.W.; Bauer, M.L.; Baylor, L.R.; Deleanu, L.E.; Fehling, D.T.; Milora, S.L. et al.
Partner: UNT Libraries Government Documents Department