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Irradiation Stability of Uranium Alloys at High Exposures

Description: Postirradiation examinations were begun of a series of unrestrained dilute uranium alloy specimens irradiated to exposures up to 13,000 MWD/T in NaK-containing stainless steel capsules. This test, part of a program of development of uranium metal fuels for desalination and power reactors sponsored by the Division of Reactor Development and Technology, has the objective of defining the temperature and exposure limits of swelling resistance of the alloyed uranium. This paper discusses those test results.
Date: March 26, 2001
Creator: McDonell, W.R.
Partner: UNT Libraries Government Documents Department

Status of Irradiation Tests of Dilute Uranium Alloys in NaK-Containing Stainless Steel Capsules

Description: To extend experience with uranium metal fuels to the high exposures required for power reactor operation, the Savannah River Laboratory has conducted over several years a series of irradiation tests of small uranium specimens of various alloy compositions in NaK-containing stainless steel capsules. These tests were designed specifically to establish the limits on exposure that could be reached during irradiation of the alloys at various temperatures without swelling and to determine the metallurgical factors that promoted the stability of the alloys. This paper discusses those test results.
Date: March 26, 2001
Creator: McDonell, W.R.
Partner: UNT Libraries Government Documents Department

C-106 High-Level Waste Solids: Washing/Leaching and Solubility Versus Temperature Studies

Description: This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing and caustic leaching on the composition of the Hanford tank C-106 high-level waste (HLW) solids. The objective of this work was to determine the composition of the C-106 solids remaining after washing with 0.01M NaOH or leaching with 3M NaOH. Another objective of this test was to determine the solubility of various C-106 components as a function of temperature. The work was conducted according to test plan BNFL-TP-29953-8,Rev. 0, Determination of the Solubility of HLW Sludge Solids. The test went according to plan, with only minor deviations from the test plan. The deviations from the test plan are discussed in the experimental section.
Date: January 26, 2000
Creator: Lumetta, G. J.; Bates, D. J.; Berry, P. K.; Bramson, J. P.; Darnell, L. P.; Farmer, O. T., III et al.
Partner: UNT Libraries Government Documents Department

LLNL high-field coil program

Description: An overview is presented of the LLNL High-Field Superconducting Magnet Development Program wherein the technology is being developed for producing fields in the range of 15 T and higher for both mirror and tokamak applications. Applications requiring less field will also benefit from this program. In addition, recent results on the thermomechanical performance of cable-in-conduit conductor systems are presented and their importance to high-field coil design discussed.
Date: March 26, 1986
Creator: Miller, J.R.
Partner: UNT Libraries Government Documents Department

Equations of state for self-excited MHD generator studies

Description: We have constructed a state-of-the-art equation of state (EOS) for argon covering the temperature density range attainable by currently proposed self-excited MHD generators. The EOS for conditions in the flow channel was obtained primarily by a non-ideal plasma code (ACTEX) that is based on a many body activity expansion. For conditions in the driver chamber the EOS was primarily obtained from a fluid code (HDFP) that calculates the fluid properties from perturbation theory based on the insulator interatomic pair potential but including electronic excitations. The results are in agreement with several sets of experimental data in the 0.6 - 91 GPa pressure range.
Date: February 26, 1980
Creator: Rogers, F.J.; Ross, M.; Haggin, G.L. & Wong, L.K.
Partner: UNT Libraries Government Documents Department

Prototype Engineered Barrier System Field Tests; Progress report

Description: This paper presents selected preliminary results obtained during the first 54 days of the Prototype Engineered Barrier System Field Tests (PEBSFT) that are being performed in G-Tunnel within the Nevada Test Site. The test described is a precursor to the Engineered Barrier Systems Field Tests (EBSFT). The EBSFT will consist of in situ tests of the geohydrologic and geochemical environment in the near field (within a few meters) of heaters emplaced in welded tuff to simulate the thermal effects of waste packages. The PEBSFTs are being conducted to evaluate the applicability of measurement techniques, numerical models, and procedures for future investigations that will be conducted in the Exploratory Shaft Facilities of the Yucca Mountain Project (YMP). The paper discusses the evolution of hydrothermal behavior during the prototype test, including rock temperatures, changes in rock moisture content, air permeability of fractures, gas pressures, and rock mass gas-phase humidity. 10 refs., 12 figs.
Date: July 26, 1989
Creator: Ramirez, A.L.; Beatty, J.; Buscheck, T.A.; Carlson, R.; Daily, W.; LaTorre, V.R. et al.
Partner: UNT Libraries Government Documents Department

Abrupt onset of a second energy gap at the superconducting transition of underdoped Bi2212

Description: he superconducting gap--an energy scale tied to the superconducting phenomena--opens on the Fermi surface at the superconducting transition temperature (Tc) in conventional BCS superconductors. In underdoped high-Tc superconducting copper oxides, a pseudogap (whose relation to the superconducting gap remains a mystery) develops well above Tc (refs 1, 2). Whether the pseudogap is a distinct phenomenon or the incoherent continuation of the superconducting gap above Tc is one of the central questions in high-Tc research3, 4, 5, 6, 7, 8. Although some experimental evidence suggests that the two gaps are distinct9, 10, 11, 12, 13, 14, 15, 16, 17, 18, this issue is still under intense debate. A crucial piece of evidence to firmly establish this two-gap picture is still missing: a direct and unambiguous observation of a single-particle gap tied to the superconducting transition as function of temperature. Here we report the discovery of such an energy gap in underdoped Bi2Sr2CaCu2O8+delta in the momentum space region overlooked in previous measurements. Near the diagonal of Cu?O bond direction (nodal direction), we found a gap that opens at Tc and has a canonical (BCS-like) temperature dependence accompanied by the appearance of the so-called Bogoliubov quasi-particles, a classical signature of superconductivity. This is in sharp contrast to the pseudogap near the Cu?O bond direction (antinodal region) measured in earlier experiments19, 20, 21.
Date: May 26, 2007
Creator: Hussain, Zahid; Lee, W.S.; Vishik, I.M.; Tanaka, K.; Lu, D.H.; Sasagawa, T. et al.
Partner: UNT Libraries Government Documents Department

The Development of Models to Optimize Selection of Nuclear Fuels through Atomic-Level Simulation

Description: Demonstrated that FRAPCON can be modified to accept data generated from first principles studies, and that the result obtained from the modified FRAPCON make sense in terms of the inputs. Determined the temperature dependence of the thermal conductivity of single crystal UO2 from atomistic simulation.
Date: January 26, 2009
Creator: Phillpot, Prof. Simon; Sinnott, Prof. Susan B.; Seifert, Prof. Hans & Tulenko, Prog. James
Partner: UNT Libraries Government Documents Department

An experimental study of adsorption in vapor-dominated geothermal systems

Description: We report results of steam adsorption experiments conducted for rock samples from vapor-dominated geothermal reservoirs. We examine the effect of the temperature on the adsorption/desorption isotherms. We find that the temperature effect is only important on the desorption such that the hysteresis becomes more pronounced as the temperature increases. The scanning behavior within the steam sorption hysteresis loop is also studied to investigate the behavior during repressurization. Collection of sets of data on the sorption behavior of The Geysers geothermal field in California is presented.
Date: January 26, 1995
Creator: Satik, Cengiz & Horne, Roland N.
Partner: UNT Libraries Government Documents Department


Description: This report documents the results of tests designed to characterize the relationship between temperature and the measured potential of electrodes installed on multi-probe corrosion monitoring systems in waste tanks. This report also documents the results of tests designed to demonstrate the impact of liquid in-leakage into electrode bodies as well as the contamination of primary reference electrodes by diffusion through the electrode tip.
Date: March 26, 2010
Partner: UNT Libraries Government Documents Department

Anisotropic intermediate valence in Yb2M3Ga9 (M = Rh, Ir)

Description: The intermediate valence compounds Yb{sub 2}M{sub 3}Ga{sub 9} (M = Rh, Ir) exhibit an anisotropic magnetic susceptibility. We report measurements of the temperature dependence of the 4f occupation number, n{sub f}(T), for Yb{sub 2}M{sub 3}Ga{sub 9} as well as the magnetic inelastic neutron scattering spectrum S{sub mag}({Delta}E) at 12 and 300 K for Yb{sub 2}Rh{sub 3}Ga{sub 9}. Both n{sub f}(T) and S{sub mag}({Delta}E) were calculated for the Anderson impurity model with crystal field terms within an approach based on the non-crossing approximation. These results corroborate the importance of crystal field effects in these materials; they also suggest that Anderson lattice effects are important to the physics of Yb{sub 2}M{sub 3}Ga{sub 9}.
Date: April 26, 2005
Creator: Christianson, A.D.; Lawrence, J.M.; Lobos, A.M.; Aligia, A.A.; Bauer, E.D.; Moreno, N.O. et al.
Partner: UNT Libraries Government Documents Department

Prerequisite requirements for higher graphite temperature limits and/or nitrogen atmosphere at all reactors

Description: The graphite temperature limits specified in the process standards-are being closely approached or have limited power levels at B, D, DR, and reactors. An increase of approximately 50--100 C in graphite temperature limits at these reactors would permit year-around operation on bulk outlet temperature limits. There has been considerable recent interest in extending to all reactors the use of nitrogen as a reactor gas constituent. With present graphite temperature limits, significant benefit from nitrogen usage will not be obtained during the winter months at reactors which are graphite temperature limited with approximately 100 per cent helium. However, during the summer months when bulk outlet temperature limitations result in graphite temperatures considerably below the maximum permissible graphite temperatures, the substitution of nitrogen for carbon dioxide could be of value. Under these circumstances, both a reduction in helium usage and a reduction in enrichment costs could result. With an increase in permissible graphite temperature limits, year-around benefit from reduced helium usage and reduced enrichment costs would be possible. To meet the Pu-240 specification with higher graphite temperatures however, would require a reduction in current goal discharge exposures with resulting increased fuel and burnout costs. Additionally, the incentives for higher graphite temperatures are very sensitive to both the mode of operation and to the assumed product worth. An economic study by the Process Analysis Unit discussing in detail the factors influencing the incentive for higher graphite temperature will be published in the near future. At a meeting among the staff several weeks ago, the prerequisite requirements for permitting higher graphite temperatures and/or nitrogen usage at all reactors were discussed. It is the purpose of this letter to briefly outline the prerequisite steps considered necessary to achieve these goals.
Date: February 26, 1962
Creator: Graves, S. M.
Partner: UNT Libraries Government Documents Department

Production losses associated with K Reactor graphite temperature limits

Description: As power levels have been raised at the K Reactors, the graphite temperature limit has caused significant production losses. These losses have come from three sources: (1) Occasions vhen pile power was directly limited because the graphite temperatures were limiting; (2) Losses in ECT because control rod movements to control graphite temperatures are not necessarily the best rod movements for pile, flattening; and (3) Losses due to lack of control in the final stages of an operating period because COp could not be used as a means of controlling long-term reactivity gains. This document attempts to establish the magnitude of these losses and shows the justification for increasing the graphite temperature limit. The data which is presented here is based upon operating data from December, 1959) through March, 1960, at KW. The results apply to KE as well as KW.
Date: April 26, 1960
Creator: Fuller, N. E.
Partner: UNT Libraries Government Documents Department

Production test IP-245-A dual area trip-out of B & C Reactor process pumps

Description: The objectives of the test described in this report are to obtain current knowledge of the flow characteristics of the B and C Reactor flow systems under various transient conditions that have a reasonable probability of occurrence. These tests will be used to revaluate the B and C Reactor bulk temperature limits, the Ball 3X low pressure trip settings, and quantitative adequacy of emergency flow from the combined high tanks - export system.
Date: March 26, 1959
Creator: Long, J. T. & Jones, S. S.
Partner: UNT Libraries Government Documents Department

K-Reactor Retubing Program graphite temperature study

Description: A project has been proposed and the funds allocated for the replacement of the central zone aluminum process tubes at both K Reactors with smooth bore zirconium process tubes of approximately the same outside diameter as the original tubes. Associated with this project is the problem of relieving the present graphite stack distortion in the vicinity of the process tube channels and counteracting or prereliving, at this time, the expected graphite stack distortion that, will take place over the next ten years. Such relief becomes increasingly important when it is realized that long reactor life is required for the zirconium tubes in order to justify the cost of the project. This justification is also based upon the ability to charge normal sized, self supported fuel elements during the reactor life of the tubes. Relieving the restrictions in the graphite process channels caused by stack contraction will be done by removing localized portions of the graphite from the tube blocks and trunion blocks with a guided cutting tool. This immediately brings up the question of graphite temperatures and the presently imposed maximum graphite in temperature limits. Combined coring and graphite stark distortion could result in excessive graphite temperatures or localized hot spots. This graphite temperature study was undertaken to permit predicting possible temperature problems that might be associated with the restoration of graphite channel straightness since the timing of the overall project completion will not allow time for extensive testing to determine such problem areas.
Date: December 26, 1962
Creator: Agar, J. D.
Partner: UNT Libraries Government Documents Department

Vibrational and Electronic Properties of Fullerene and Carbon-Based Clustors. Final Reports for period July 1, 1997 - June 30, 2001

Description: Lattice dynamics is of central importance for the mechanism of ferroelectricity. In particular, the soft mode behaviors are directly related to many of their ferroelectric and dielectric properties. In this project, we have carried out experimental studies of the vibrational spectra of SrTiO{sub 3} films grown by pulsed laser deposition using a metal-oxide bilayer structure. Raman scattering, with and without bias electric field, and Fourier-transform far-infrared ellipsometry were utilized. These results are compared with the low-frequency dielectric properties. We found that in the films the soft mode is harder compared to that in bulk crystals, in agreement with the Lyddane-Sachs-Teller (LST) formalism. We have studied electric field-induced Raman scattering in SrTiO{sub 3} thin films using an indium-tin oxide/SrTiO{sub 3}/SrRuO{sub 3} structure. The soft mode polarized along the field becomes Raman active. Experimental data for electric field-induced hardening of the soft modes and the tuning of the static dielectric constant are in agreement described by the LST formalism. The markedly different behavior of the soft modes in thin films from that in the bulk is explained by the existence of local polar regions. The study was extended to Ba{sub x}Sr{sub 1-x}TiO{sub 3} films with Ba contents x = 0.05, 0.1, 0.2 and 0.5. The temperature dependence of the soft mode frequency shows evidence of the ferroelectric phase transition in the films. Relative Raman intensity of hard phonon modes shows the ferroelectric phase transition occurs over a broad range of temperatures in thin films, which is different from bulk behavior. Comparison of temperature evolution of Raman spectra for films grown on SrTiO{sub 3} and LaAlO{sub 3} substrates shows the influence of strain on the temperature of ferroelectric phase transition.
Date: November 26, 2002
Creator: Xi, X.
Partner: UNT Libraries Government Documents Department

Long-Term Waste Package Degradation Studies at the Yucca Mountain Potential High-Level Nuclear Waste Repository

Description: The Site Recommendation (SR) process for the potential repository for spent nuclear fuel (SNF) and high-level nuclear waste (HLW) at Yucca Mountain, Nevada is underway. Fulfillment of the requirements for substantially complete containment of the radioactive waste emplaced in the potential repository and subsequent slow release of radionuclides from the Engineered Barrier System (EBS) into the geosphere will rely on a robust waste container design, among other EBS components. Part of the SR process involves sensitivity studies aimed at elucidating which model parameters contribute most to the drip shield and waste package degradation characteristics. The model parameters identified included (a) general corrosion rate model parameters (temperature-dependence and uncertainty treatment), and (b) stress corrosion cracking (SCC) model parameters (uncertainty treatment of stress and stress intensity factor profiles in the Alloy 22 waste package outer barrier closure weld regions, the SCC initiation stress threshold, and the fraction of manufacturing flaws oriented favorably for through-wall penetration by SCC). These model parameters were reevaluated and new distributions were generated. Also, early waste package failures due to improper heat treatment were added to the waste package degradation model. The results of these investigations indicate that the waste package failure profiles are governed by the manufacturing flaw orientation model parameters and models used.
Date: February 26, 2002
Creator: Mon, K. G.; Bullard, B. E.; Longsine, D. E.; Mehta, S.; Lee, J. H. & Monib, A. M.
Partner: UNT Libraries Government Documents Department