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Calibrations of a tritium extraction facility

Description: A tritium extraction facility has been built for the purpose of measuring the absolute tritium concentration in neutron-irradiated lithium metal samples. Two independent calibration procedures have been used to determine what fraction, if any, of tritium is lost during the extraction process. The first procedure compares independently measured /sup 4/He and /sup 3/H concentrations from the /sup 6/Li(n,..cap alpha..)T reaction. The second procedure compared measured /sup 6/Li(n,..cap alpha..)T//sup 197/Au (n,..gamma..)/sup 198/Au thermal neutron reaction rate ratios with those obtained from Monte Carlo calculations using well-known cross sections. Both calibration methods show that within experimental errors (approx. 1.5%) no tritium is lost during the extraction process.
Date: January 1, 1983
Creator: Bretscher, M.M.; Oliver, B.M. & Farrar, H. IV
Partner: UNT Libraries Government Documents Department

Annual dose rate calculations for thermoluminescence dating

Description: Tabulations of decay data and dose rate calculations that are necessary for TL dating are presented. An effort has been made to collect the latest evaluated data and to catalog them in a form that is easily accessible, so that they may be updated as new revised values are reported. It is suggested that the largest error in thermoluminescence dating will come from sources other than the tabulated particle energies and branching ratios. These include: (a) the alpha to beta thermoluminescence efficiency determination; (b) concentration measurements of K, Rb, Th, and U; (c) all departures from secular equilibrium in the uranium and thorium decay chains; and (d) the imprecise calibration of laboratory radiation sources.
Date: January 1, 1978
Creator: Carriveau, G W & Troka, W
Partner: UNT Libraries Government Documents Department

Effect of interacting particles on primordial nucleosynthesis

Description: We modify the standard model for big-bang nucleosynthesis to allow for the presence of a generic particle species, i.e., one which maintains good thermal contact with either the photons or the light neutrino species throughout the epoch of primordial nucleosynthesis. The production of D, /sup 3/He, /sup 4/He, and /sup 7/Li is calculated as a function of the mass, degrees of freedom, and spin statistics of the generic particle. We show that in general, the effect of an additional generic species cannot simply be parameterized as the equivalent number of additional light neutrino species. The presence of generic particles also affects the predicted value for the neutrino-to-photon temperature ratio.
Date: May 1, 1986
Creator: Kolb, E.W.; Turner, M.S. & Walker, T.P.
Partner: UNT Libraries Government Documents Department

Calculated thickness of tungsten alloy required for specified attenuation of gamma radiation from sup 137 CS

Description: The traditional method of evaluating and calibrating health physics instruments is to use a calibrator that consists of a single high-activity gamma radiation source with different attenuators to select the radiation level desired for tesing. To have accurate radiation intensities inside the calibrator cavity, the attenuators must be designed from precise absorption calculations. This paper reports calculations made to determine the thickness of tungsten alloy metal required for specific attenuation. These calculations include the buildup contribution by secondary scattering radiation, and they are compared to values calculated with the buildup factor omitted. 3 refs., 2 figs., 3 tabs.
Date: January 1, 1991
Creator: Chiles, M.M.; Allin, G.W. & Pace, J.V. III.
Partner: UNT Libraries Government Documents Department

Capsule calorimeter development report

Description: A capsule calorimeter has been designed, fabricated, and tested that is capable of measuring the rate of thermal energy generation of a capsule source with an accuracy of plus or minus five percent over a range of 300 watts to 1,000 watts of power. Three operating modes were investigated. The rate of temperature rise mode of operation was found to be the superior operating mode based on accuracy, time cycle, and simplicity of operation. This mode of operation is recommended for use in the encapsulation plant for performing calorimetric determinations on the strontium and cesium capsules that will be produced in the plant. The heat generation data collected by calorimetry will be used for isotopic assay of the capsule sources. The capsule calorimeter is specifically designed for installation into a remotely operated hot cell.
Date: October 2, 1972
Creator: Hall, J.C.
Partner: UNT Libraries Government Documents Department

An assessment of the base blanket for ITER

Description: Ideally, the ITER base blanket would provide the necessary tritium for the reactor to be self-sufficient during operation, while having minimal impact on the overall reactor cost, reliability and safety. A solid breeder blanket has been developed in CDA phase in an attempt to achieve such objectives. The reference solid breeder base blanket configurations at the end of the CDA phase has many attractive features such as a tritium breeding ratio (TBR) of 0.8--0.9 and a reasonably low tritium inventory. However, some concerns regarding the risk, cost and benefit of the base blanket have been raised. These include uncertainties associated with the solid breeder thermal control and the potentially high cost of the amount of Be used to achieve high TBR and to provide the necessary thermal barrier between the high temperature solid breeder and low temperature coolant. This work addresses these concerns. The basis for the selection of a breeding blanket is first discussed in light of the incremental risk, cost and benefits relative to a non-breeding blanket. Key issues associated with the CDA breeding blanket configurations are then analyzed. Finally, alternative schemes that could enhance the attractiveness and flexibility of a breeding blanket are explored.
Date: January 1, 1991
Creator: Raffray, A.R.; Abdou, M.A. & Ying, A.
Partner: UNT Libraries Government Documents Department

Measurement of the energy dependent beta asymmetry in the decay of /sup 8/Li

Description: Progress is reported on a new measurement of the beta decay asymmetry in /sup 8/Li. Polarized /sup 8/Li is produced via the reaction /sup 7/Li(d,p)/sup 8/Li using vector polarized deuterons from a crossed beam polarized source. Plastic scintillation electron counters are used to measure asymmetry, tensor polarization correlation and to monitor beam current. Results are graphed and systematic error sources are discussed. 4 refs. (LEW)
Date: January 1, 1985
Creator: Bigelow, R.A.; Quin, P.A.; Freedman, S.J. & Napolitano, J.
Partner: UNT Libraries Government Documents Department

Alpha particle diagnostic beam line system to generate an intense Li/sup 0/ beam with an ORNL SITEX source

Description: The Oak Ridge National Laboratory (ORNL) SITEX (Surface Ionization with Transverse Extraction) negative ion source utilizes a 100-V/20-A reflex arc discharge in a 1300-gauss magnetic field to generate Cs+ ions and H+ or D+ ions, depending on the beam required. A shaped molybdenum plate is placed directly behind the arc column. Cesium coverage on this plate is used to minimize the surface work function, which requires two-thirds of a monolayer coverage. Cesium coverage ia adjusted both by cesium flow control into the arc discharge chamber and by temperature control of the converter using gaseous-helium cooling channels in the converter plate. Normal converter operational temperatures are 300/sup 0/ to 500/sup 0/C H/sup -//D/sup -/ beams are generated at the biased converter surface (-150 V with respect to the anode) by Cs/sup +/ sputtering of absorbed hydrogen or deuterium and by the reflection-conversion mechanism of H/sup +//D/sup +/ ions which strike the converter surface at 150 eV. The negative ions are accelerated through the 150-V plasma sheath at the converter surface and are focused by the converter geometry and magnetic field so as to pass through the exit aperture with minimum angular divergence. The ion optics of the SITEX accelerator has been calculated using the ORNL 3-D optics code and results in a divergence perpendicular to the slot of theta/sub perpendicular rms/ = 0.35/sup 0/ and parallel to the slot of theta/sub parallel rms/ = 0.18/sup 0/. This beam divergence should be adequate for injection into a radio frequency quadrupole (RFQ) for further acceleration.
Date: January 1, 1985
Creator: Dagenhart, W.K.; Stirling, W.L.; Tsai, C.C. & Whealton, J.H.
Partner: UNT Libraries Government Documents Department

Cesium diffusion in graphite

Description: Experiments on diffusion of /sup 137/Cs in five types of graphite were performed. The document provides a completion of the report that was started and includes a presentation of all of the diffusion data, previously unpublished. Except for data on mass transfer of /sup 137/Cs in the Hawker-Siddeley graphite, analyses of experimental results were initiated but not completed. The mass transfer process of cesium in HS-1-1 graphite at 600 to 1000/sup 0/C in a helium atmosphere is essentially pure diffusion wherein values of (E/epsilon) and ..delta..E of the equation D/epsilon = (D/epsilon)/sub 0/ exp (-..delta..E/RT) are about 4 x 10/sup -2/ cm/sup 2//s and 30 kcal/mole, respectively.
Date: May 1, 1980
Creator: Evans, R.B. III; Davis, W. Jr. & Sutton, A.L. Jr.
Partner: UNT Libraries Government Documents Department

Cesium-137 source material for an irradiator

Description: The feasibility of using /sup 137/Cs for the gamma source in sludge irradiators is discussed. It was concluded that /sup 137/Cs, because of its availability in large quantities as a by-product of fission in nuclear reactors, is an excellent candidate source for use in sewage sludge irradiators. The capsules used to store /sup 137/CsCl in the Waste Encapsulation and Storage Facility embody the technology gained by extensive development and experience during the past 25 years. The WESF capsule provides a rugged, well-proved containment of /sup 137/CsCl that has been shown to be resistant to a series of unusual stresses.
Date: January 1, 1980
Creator: Lamb, E.
Partner: UNT Libraries Government Documents Department

Gamma-ray spectral calculations for uranium borehole logging

Description: Gamma-ray transport calculations were performed to determine the energy distribution of gamma rays inside a borehole introduced into an infinite medium. The gamma rays from the naturally occurring radioactive isotopes of potassium, thorium, and uranium were uniformly distributed in a sandstone formation (having a porosity of 0.30 and a saturation of 1.0) surrounding the borehole. A sonde was placed coaxially inside the borehole. Parametric studies were done to determine how the borehole radius, borehole fluid, and borehole casing influence the gamma-ray flux inside the sonde.
Date: June 1, 1980
Creator: Close, D.A.; Evans, M.L. & Jain, M.
Partner: UNT Libraries Government Documents Department

Mass-reduced quantum numbers: application to the isotopic lithium hydrides (X/sup 1/B/sup +/)

Description: The massed-reduced quantum number (MRQN) method of combining isotopic data is applied to the lithium hydride X/sup 1/..sigma../sup +/ ground state. The ..delta..G(eta) = ..mu../sup /sup 1///sub 2// ..delta..G(v), B(eta) = ..mu..B(v) and D(eta) = ..mu../sup 2/D(v) isotopically-combined functions are obtained. An isotopically-combined Rydberg-Klein Rees (ICRKR) potential is constructed using the G(eta) and B(eta) functions. Evidence for breakdown of the Born-Oppenheimer approximation is presented and examined. The Dunham, Simons-Parr-Finlan, and Thakkar methods of potential expansion are also applied to lithium hydride and compared to the RKR Potential.
Date: January 1, 1977
Creator: Li, K.C. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Radiative lifetimes for vibrational levels of the B /sup 1/PI state of /sup 7/LiH. [Probabilities, bound-free probability]

Description: Newly calculated radiative transition probabilities for the B /sup 1/PI ..-->.. X /sup 1/..sigma../sup +/ and A /sup 1/..sigma../sup +/ emission bands of /sup 7/LiH are used to calculate the radiative lifetime of the various vibrational levels (0 less than or equal to v' less than or equal to 2) of B /sup 1/PI LiH. An estimate of the B ..-->.. X bound-free emission probability is also included, although the lifetimes are dominated by the B ..-->.. X bound-bound emission. The calculated radiative lifetimes increase rapidly with v' from 11.3 nsec at v' = 0 to 17.0 nsec at v' = 1 and then 24.0 nsec at v' = 2.
Date: January 1, 1978
Creator: Zemke, W.T. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Radiative and nonradiative lifetimes for vibrational levels of the A /sup 1/. sigma. /sup +/ state of /sup 7/LiH. [Transition probabilities]

Description: Newly calculated radiative transition probabilities for the A /sup 1/..sigma../sup +/ ..-->.. X /sup 1/..sigma../sup +/ (v' -v'') emission bands of /sup 7/LiH re used to calculate the radiative lifetime of the various vibrational levels (0 < or = v' < or = 26) of A /sup 1/..sigma../sup +/ LiH. For higher levels, an estimate of the bound-to-free emission probability is also needed and included. For the highest two levels, A /sup 1/..sigma../sup +/ ..-->.. B /sup 1/PI emission is possible and has been included, but makes a negligible contribution to the radiative lifetime. The calculated radiative lifetimes increase with v' from 28.9 nsec at v' = 0 to 36.1 nsec at v' = 16 and then decrease to 27.1 nsec at v' = 26. They are found to be in good agreement with measured total lifetimes, implying the nonradiative (predissociative) lifetime for the measured levels is approximately > 10/sup -7/ seconds, in accord with simple theoretical expectations.
Date: January 1, 1977
Creator: Zemke, W.T.; Crooks, J.B. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Radiative transition probabilities for the A /sup 1/. sigma. --X /sup 1/. sigma. /sup +/ bands of /sup 7/LiH. [Tables]

Description: The recently reported (J. Chem. Phys. 66, 5412 (1977)) hybrid potential curves for the X /sup 1/..sigma../sup +/ and A /sup 1/..sigma../sup +/ states of LiH are combined with the ab initio transition moments of Docken and Hinze (J. Chem. Phys. 57, 4936 (1972)) to calculate radiative transition probabilities between all upper (v' < or = 26) and all lower (v'' < or = 23) vibrational levels of /sup 7/LiH. By far the strongest single band found is the 23 to 26 band between the highest ''long-range'' levels in each potential. A comparison with experimental intensity observations is made; it appears that the experiments are globally in accord with calculations, but with some detailed differneces discussed herein.
Date: January 1, 1977
Creator: Zemke, W.T. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Operating experience of an ECR ion source on a high voltage platform

Description: The ATLAS PII-ECR ion source is the first ECR ion source to be designed for operation on a high voltage platform. The source system is required to provide beams of heavy ions with a velocity of 0.01c for subsequent acceleration by the superconducting ATLAS Positive Ion Injector linac. The ability of the system to provide high charge state ions with velocities up to .01c is possibly unique in the world today and as such has generated significant interest in the atomic physics community. A beamline for atomic physics has been installed and is now in use. The source began operation in October, 1987. The source capabilities and operating experience to date will be discussed. Other ECR-accelerator combinations will be compared to the ATLAS system. 10 refs., 3 figs., 3 tabs.
Date: January 1, 1988
Creator: Pardo, R.
Partner: UNT Libraries Government Documents Department

Source of monoenergetic electrons for beta dosimetry

Description: We have developed an electron spectrometer which can produce a continuous beam of monoenergetic electrons. The spectrometer uses 20 millicuries of Cs-137 as a source of electrons which can be magnetically focused at the exit port. Various electron energies can be selected by changing the magnetic field. The maximum electron energy and dose rate for the present design are approximately 630 keV and 1.5 rads per hour, respectively.
Date: January 1, 1983
Creator: Graham, C.L. & Elliott, J.H.
Partner: UNT Libraries Government Documents Department

Primordial lithium: New reaction rates, new abundances, new constraints

Description: Newly measured nuclear reaction rates for /sup 3/H(..cap alpha..,..gamma..)/sup 7/Li (higher than previous values) and /sup 7/Li(p,..cap alpha..)/sup 4/He (lower than previous values) are shown to increase the /sup 7/Li yield from big bang nucleosynthesis for lower baryon to photon ratio (eta less than or equal to 4 x 10/sup -10/); the yield for higher eta is not affected. New, independent determinations of Li abundances in extreme Pop II stars are in excellent agreement with the earlier work of the Spites and give continued confidence in the use of /sup 7/Li in big bang baryon density determinations. The new /sup 7/Li constraints imply a lower limit on eta of 2 x 10/sup -10/ and an upper limit of 5 x 10/sup -10/. This lower limit to eta is concordant with that obtained from considerations of D + /sup 3/He. The upper limit is consistent with, but even more restrictive than, the D bound. With the new rates, any observed primordial Li/H ratio below 10/sup -10/ would be inexplicable by the standard big bang nucleosynthesis. A review is made of the strengths and possible weaknesses of utilizing conclusions drawn from big bang lithium considerations. An appendix discusses the null effect of a factor of 32 increase in the experimental rate for the D(d,..gamma..)/sup 4/He reaction. 28 refs., 1 fig.
Date: December 1, 1986
Creator: Kawano, L.; Schramm, D. & Steigman, G.
Partner: UNT Libraries Government Documents Department

Nucleosynthesis in a baryon-inhomogeneous universe with coupled baryon diffusion

Description: Detailed calculations of big-bang nucleosynthesis in baryon-inhomogeneous universes show that {Omega}{sub b} can be considerably larger than its limit from standard big-bang nucleosynthesis. Such results require that late-time hydrodynamic effects deplete overproduction of {sup 7}Li and that the QCD surface tension be near the cube of the QCD coexistence temperature for fluctuations of the correct length scales to arise. 15 refs., 1 fig.
Date: August 2, 1990
Creator: Meyer, B.S.
Partner: UNT Libraries Government Documents Department

Ion exchange flowsheet for recovery of cesium from purex sludge supernatant at B Plant

Description: Purex Sludge Supernatant (PSS) contains significant amounts of /sup 137/Cs left after removal of strontium from fission product bearing Purex wastes. To remove cesium from PSS, an Ion Exchange Recovery system has been set up in Cells 17-21 at B Plant. The cesium that is recovered is stored within B Plant for eventual purification through the Cesium Purification process in Cell 38 and eventual encapsulation and storage in a powdered form at the Waste Encapsulation Storage Facility. Cesium depleted waste streams from the Ion Exchange processes are transferred to underground storage.
Date: April 29, 1977
Creator: Carlstrom, R.F.
Partner: UNT Libraries Government Documents Department

Preparation and characterization of cesium-137 aluminosilicate pellets for radioactive source applications

Description: Twenty-seven fully loaded /sup 137/Cs aluminosilicate pellets were fabricated in a hot cell by the vacuum hot pressing of a cesium carbonate/montmorillonite clay mixture at 1500/sup 0/C and 570 psig. Four pellets were selected for characterization studies which included calorimetric measurements, metallography, scanning electron microscope and electron backscattering (SEM-BSE), electron microprobe, x-ray diffraction, and cesium ion leachability measurements. Each test pellet contained 437 to 450 curies of /sup 137/Cs as determined by calorimetric measurements. Metallographic examinations revealed a two-phase system: a primary, granular, gray matrix phase containing large and small pores and small pore agglomerations, and a secondary fused phase interspersed throughout the gray matrix. SEM-BSE analyses showed that cesium and silicon were uniformly distributed throughout both phases of the pellet. This indicated that the cesium-silicon-clay reaction went to completion. Aluminum homogeneity was unconfirmed due to the high background noise associated with the inherent radioactivity of the test specimens. X-ray diffraction analyses of both radioactive and non-radioactive aluminosilicate pellets confirmed the crystal lattice structure to be pollucite. Cesium ion quasistatic leachability measurements determined the leach rates of fully loaded /sup 137/Cs sectioned pollucite pellets to date to be 4.61 to 34.4 x 10/sup -10/ kg m/sup -2/s/sup -1/, while static leach tests performed on unsectioned fully loaded pellets showed the leach rates of the cesium ion to date to be 2.25 to 3.41 x 10/sup -12/ kg m/sup -2/s/sup -1/. The cesium ion diffusion coefficients through the pollucite pellet were calculated using Fick's first and second laws of diffusion. The diffusion coefficients calculated for three tracer level /sup 137/Cs aluminosilicate pellets were 1.29 x 10/sup -16/m/sup 2/s/sup -1/, 6.88 x 10/sup -17/m/sup 2/s/sup -1/, and 1.35 x 10/sup -17/m/sup 2/s/sup -1/, respectively.
Date: July 1, 1981
Creator: Schultz, F.J.; Tompkins, J.A.; Haff, K.W. & Case, F.N.
Partner: UNT Libraries Government Documents Department