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Sequential probability ratio controllers for safeguards radiation monitors (open access)

Sequential probability ratio controllers for safeguards radiation monitors

Sequential hypothesis tests applied to nuclear safeguards accounting methods make the methods more sensitive to detecting diversion. The sequential tests also improve transient signal detection in safeguards radiation monitors. This paper describes three microprocessor control units with sequential probability-ratio tests for detecting transient increases in radiation intensity. The control units are designed for three specific applications: low-intensity monitoring with Poisson probability ratios, higher intensity gamma-ray monitoring where fixed counting intervals are shortened by sequential testing, and monitoring moving traffic where the sequential technique responds to variable-duration signals. The fixed-interval controller shortens a customary 50-s monitoring time to an average of 18 s, making the monitoring delay less bothersome. The controller for monitoring moving vehicles benefits from the sequential technique by maintaining more than half its sensitivity when the normal passage speed doubles.
Date: January 1, 1984
Creator: Fehlau, P. E.; Coop, K. L. & Nixon, K. V.
System: The UNT Digital Library
Electron attachment fo halocarbons of interest in gaseous dielectrics (open access)

Electron attachment fo halocarbons of interest in gaseous dielectrics

Total electron attachment rate constants and cross sections for halomethane and haloethane (freon) compounds are summarized and new results are reported for haloethylenes. The relationship between the electron attachment cross section and the breakdown strength of dielectric gases reported earlier is further discussed.
Date: January 1, 1984
Creator: McCorkle, D. L.; Christodoulides, A. A. & Christophorou, L. G.
System: The UNT Digital Library
Hydrogen transport, mixing, and combustion studies (open access)

Hydrogen transport, mixing, and combustion studies

The transport, mixing, and burning of hydrogen inside containments are receiving a great deal of attention. We present detailed models describing this important phenomena and provide several example calculations to show the versatility and accuracy of the methods.
Date: January 1, 1984
Creator: Travis, J. R.
System: The UNT Digital Library
Ceramics for fusion devices (open access)

Ceramics for fusion devices

Ceramics are required for a number of applications in fusion devices, among the most critical of which are magnetic coil insulators, windows for RF heating systems, and structural uses. Radiation effects dominate consideration of candidate materials, although good pre-irradiation properties are a requisite. Materials and components can be optimized by careful control of chemical and microstructural content, and application of brittle material design and testing techniques. Future directions for research and development should include further extension of the data base in the areas of electrical, structural, and thermal properties; establishment of a fission neutron/fusion neutron correlation including transmutation gas effects; and development of new materials tailored to meet the specific needs of fusion reactors.
Date: January 1, 1984
Creator: Clinard, F. W. Jr.
System: The UNT Digital Library
Evaluation of selected approximations used in pressure vessel fluence calculations (open access)

Evaluation of selected approximations used in pressure vessel fluence calculations

In response to concerns over the issue of Pressurized Thermal Shock (PTS), Brookhaven National Laboratory (BNL), under the direction of the USNRC, has developed and benchmarked a methodology for calculating pressure vessel (PV) (>1-MeV) damage fluence. The methodology is based on the DOT-3.5 discrete ordinates transport code and has been shown to yield fluence results in good agreement with measurements and results from other calculations. This paper describes the basic methodology employed in BNL PV fluence calculations, and the results of a number of studies performed to assess the impact of various special effects on the calculated (>1-MeV) PV fluence.
Date: January 1, 1984
Creator: Todosow, M.; Carew, J. F. & Kohut, P.
System: The UNT Digital Library
Design, fabrication, and testing of the BNL radio frequency quadrupole accelerator (open access)

Design, fabrication, and testing of the BNL radio frequency quadrupole accelerator

The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS utilizes a Radio Frequency Quadrupole Accelerator for acceleration between the polarized source and the Alvarez Linac. Although operation has commenced with a few ..mu.. amperes of H/sup -/ beam, it is anticipated that future polarized H/sup -/ sources will have a considerably improved output. The RFQ will operate at 201.25 MHz and will be capable of handling a beam current of 0.02 amperes with a duty cycle of 0.25%. The resulting low average power has allowed novel solutions to the problems of vane alignment, rf current contacts, and removal of heat from the vanes. The design philosophy, details of cavity fabrication, and vane machining will be discussed. Results of low and high power rf testing will be presented together with the initial results of operations in the polarized H/sup -/ beam line.
Date: January 1, 1984
Creator: Brown, H.; Clifford, T.; Giordano, S.; Khiari, F.; McKenzie-Wilson, R.; Puglisi, M. et al.
System: The UNT Digital Library
Some uncertainties associated with self-calibration of microPIXE analysis (open access)

Some uncertainties associated with self-calibration of microPIXE analysis

The technique of self-calibration, based on internal labelling of target samples with known amounts of a given element, is often used in conventional PIXE analysis of environmental and biological samples, usually when a large number of samples is to be analyzed. However, extreme care should be exercised when attempting to use self-calibration procedures for microPIXE analysis, because the microdistribution of the labelling element in a drop of solution, for example, is usually nonuniform and particle microbeams with a homogeneous profile are difficult to obtain. This paper presents the results of a series of scanning irradiations by a 20 ..mu..m proton beam across dried solution drops containing known initial concentrations of thorium which had been deposited onto two different backings. Nonuniform distribution of thorium within the dried drops was observed.
Date: January 1, 1984
Creator: Paschoa, A. S.; Wrenn, M. E.; Bruenger, F. W.; Cholewa, M. & Jones, K. W.
System: The UNT Digital Library
Initial conditioning of the TFTR vacuum vessel (open access)

Initial conditioning of the TFTR vacuum vessel

We report on the initial conditioning of the Tokamak Fusion Test Reactor (TFTR) vacuum vessel prior to the initiation of first plasma discharges, and during subsequent operation with high power ohmically-heated plasmas. Following evacuation of the 86 m/sup 3/ vessel with the 10/sup 4/ 1/s high vacuum pumping system, the vessel was conditioned by a 15 A dc glow discharge in H/sub 2/ at a pressure of 5 mTorr. Rapid-pulse discharge cleaning was used subsequently to preferentially condition the graphite plasma limiters. The effectiveness of the discharge cleaning was monitored by measuring the exhaust rates of the primary discharge products (CO/C/sub 2/H/sub 4/, CH/sub 4/, and H/sub 2/O). After 175 hours of glow discharge treatment, the equivalent of 50 monolayers of C and O was removed from the vessel, and the partial pressures of impurity gases were reduced to the range of 10/sup -9/-10/sup -10/ Torr.
Date: January 1, 1984
Creator: Dylla, H. F.; Blanchard, W. R.; Krawchuk, R. B.; Hawryluk, R. J. & Owens, D. K.
System: The UNT Digital Library
Lumped-circuit model of four-vane RFQ resonator (open access)

Lumped-circuit model of four-vane RFQ resonator

Although the rf cavity code SUPERFISH is a necessary tool for designing rf cavities, it is often useful to have approximate analytic formulas for the electromagnetic properties of a cavity. One approach for the RFQ four-vane cavity is to use the analtytic solutions associated with an inclined plane waveguide. The large capacitive vane loading in the four-vane RFQ resonator allows a convenient representation by a simple lumped-circuit model. Formulas are derived that depend on a single unknown parameter: the vane capacitance per unit length, which can be calculated for different vane geometries using SUPERFISH. The formulas from the model are useful for estimating the RFQ's electromagnetic properties as a function of parameters such as frequency and intervane voltage.
Date: January 1, 1984
Creator: Wangler, T. P.
System: The UNT Digital Library
General-purpose RFQ design program (open access)

General-purpose RFQ design program

We have written a general-purpose, radio-frequency quadrupole (RFQ) design program that allows maximum flexibility in picking design algorithms. This program optimizes the RFQ on any combination of design parameters while simultaneously satisfying mutually compatible, physically required constraint equations. It can be very useful for deriving various scaling laws for RFQs. This program has a friendly user interface in addition to checking the consistency of the user-defined requirements and is written to minimize the effort needed to incorporate additional constraint equations. We describe the program and present some examples.
Date: January 1, 1984
Creator: Wadlinger, E. A.
System: The UNT Digital Library
Photon losses in cosmic ray acceleration in active galactic nuclei (open access)

Photon losses in cosmic ray acceleration in active galactic nuclei

The usual assumption of the acceleration of ultrahigh energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies, and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 13/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultrahigh energy cosmic ray 10/sup 20/ eV by greater than 10/sup 4/ times its energy. Hence, it is unlikely that any reasonable configuration of acceleration can avoid disastrous photon energy loss. A different site for ultrahigh energy cosmic ray acceleration must be found.
Date: January 1, 1984
Creator: Colgate, S. A.
System: The UNT Digital Library
Status, plans, and capabilities of the Nuclear Criticality Information System (open access)

Status, plans, and capabilities of the Nuclear Criticality Information System

The Nuclear Criticality Information System (NCIS), in preparation since 1981, has substantially evolved and now contains a growing number of resources pertinent to nuclear criticality safety. These resources include bibliographic compilations, experimental data, communications media, and the International Directory of Nuclear Criticality Safety Personnel. These resources are part of the LLNL Technology Information System (TIS) which provides the host computer for NCIS. The TIS provides nationwide access to authorized members of the nuclear criticality community via interactive dial-up from computer terminals that utilize communication facilities such as commercial and federal telephone networks, toll-free WATS lines, TYMNET, and the ARPANET/MILNET computer network.
Date: January 6, 1984
Creator: Koponen, B. L.
System: The UNT Digital Library
Refractory alloy technology for space nuclear power applications (open access)

Refractory alloy technology for space nuclear power applications

Purpose of this symposium is twofold: (1) to review and document the status of refractory alloy technology for structural and fuel-cladding applications in space nuclear power systems, and (2) to identify and document the refractory alloy research and development needs for the SP-100 Program in both the short and the long term. In this symposium, an effort was made to recapture the space reactor refractory alloy technology that was cut off in midstream around 1973 when the national space nuclear reactor program began in the early 1960s, was terminated. The six technical areas covered in the program are compatibility, processing and production, welding and component fabrication, mechanical and physical properties, effects of irradiation, and machinability. The refractory alloys considered are niobium, molybdenum, tantalum, and tungsten. Thirteen of the 14 pages have been abstracted separately. The remaining paper summarizes key needs for further R and D on refractory alloys. (DLC)
Date: January 1, 1984
Creator: Cooper, R. H., Jr. & Hoffman, E. E.
System: The UNT Digital Library
Ohmic heating to 100-eV and helicity injection in CTX (open access)

Ohmic heating to 100-eV and helicity injection in CTX

In the year since the last CT symposium, two major CTX results have been achieved. Electron temperatures over 100 eV have been obtained and the magnetic fields of the spheromaks have been sustained by helicity injection from the coaxial magnetized plasma source. The behavior and magnitude of the fields in the spheromak can be predicted from just the source voltage and flux by assuming a constant rate of helicity loss by resistive decay.
Date: January 1, 1984
Creator: Henins, I.; Barnes, C. W.; Hoida, H. W.; Jarboe, T. R.; Klingner, P. L.; Knox, S. O. et al.
System: The UNT Digital Library
Octupole shaps in nuclei, and some rotational consequences thereof (open access)

Octupole shaps in nuclei, and some rotational consequences thereof

During the last years a large number of experimental papers presenting spectroscopic evidence for collective dipole and octupole deformations have appeared. Many theoretical attempts have been made to explain the observed spectroscopic properties in terms of stable octupole deformations. The coupling by the octupole potential, being proportional to Y/sub 30/, is strongest for those subshells for which ..delta..1 = 3. Therefore the tendency towards octupole deformation occurs just beyond closed shells where the high-j intruder subshells (N,1,j) lie very close to the normal parity subshells (N-1,1-3,j-3), i.e. for the particle numbers 34 (g/sub 9/2/-p/sub 3/2/), 56 (h/sub 11/2/-d/sub 5/2/). 9C (i/sub 13/2/-f/sub 7/2/) and 134 (j/sub 15/2/-g/sub 9/2/). Empirically, it is specifically for the particle numbers listed above that negative parity states are observed at relatively low energies in doubly even nuclei. From the different combinations of octupole-driving particle numbers four regions of likely candidates for octupole deformed equilibrium shapes emerge, namely the neutron-deficient nuclei with Z approx. = 90, N approx. = 134 (light actinides) and Z approx. = 34, N approx. = 34 (A approx. = 70) and the neutron-rich nuclei with Z approx. = 56, N approx. = 90 (heavy Ba) and Z approx. = 34, N/sup …
Date: January 1, 1984
Creator: Nazarewicz, W.; Olanders, P.; Ragnarsson, I.; Dudek, J. & Leander, G. A.
System: The UNT Digital Library
Minet validation study using EBR-II transient data (open access)

Minet validation study using EBR-II transient data

The MINET code, developed to simulate large and complex thermal-hydraulic systems, such as balance of plant, was used to simulate an EBR-II test transient. MINET calculations agreed well with measured parameters, confirming the validity of the basic MINET methodology and key component models.
Date: January 1, 1984
Creator: Van Tuyle, G. J.
System: The UNT Digital Library
Space resolved absolutely calibrated VUV spectroscopic measurements on CTX (open access)

Space resolved absolutely calibrated VUV spectroscopic measurements on CTX

Space resolved particle confinement times have been measured in two independent methods in CTX. The confinement time near the magnetic axis was found to be tau/sub p/ approx. 100 ..mu..s and a factor of two lower for the outer flux surfaces. Attempts at sustainment so far have resulted in cold plasmas and additional impurities being injected with the flux. This problem is being specifically addressed in the electrode facility.
Date: January 1, 1984
Creator: Hoida, H. W.; Barnes, C. W.; Henins, I.; Jarboe, T. R. & Sherwood, A. R.
System: The UNT Digital Library
Hypernuclear research at the AGS (open access)

Hypernuclear research at the AGS

Although the field of hypernuclear research is over 30 years old, progress in exploring the detailed behavior of hypernuclei has been slow. This fact is due mainly to the technical problems of producing and studying these strange objects. Indeed each step in the improvement of technique has been accompanied by a breakthrough in our understanding of this fascinating subject. In this paper, the aim is to describe the evolution of hypernuclear research, stressing especially the contributions of the program based on the Brookhaven AGS. 23 references, 17 figures, 1 table.
Date: January 1, 1984
Creator: Chrien, R. E.
System: The UNT Digital Library
Unitary, unified models for NN. -->. NN. pi (open access)

Unitary, unified models for NN. -->. NN. pi

First-generation unitary, unified models reproduce the new NN ..-->.. NN..pi.. data reasonably well, but there are two interesting warts in the comparison of theory and experiment. 20 references.
Date: January 1, 1984
Creator: Silbar, R. R.
System: The UNT Digital Library
Impact of fluid expansion and contraction on completion techniques for hot wells (open access)

Impact of fluid expansion and contraction on completion techniques for hot wells

The thermal expansion and contraction of fluid with large changes in temperature can cause significant changes in (1) fluid displacement volumes, (2) pressure gradients in columns of fluid, (3) compressibility of the fluid, and (4) pressure in unported enclosures. In conjunction with the completion of Fenton Hill Hot Dry Rock (HDR) Wells EE-2 and EE-3 methods have been developed to calculate and compensate for expansion and contraction of wellbore fluids. These methods are outlined and specific operations where the methods were developed and used are described.
Date: January 1, 1984
Creator: Dreesen, D. S. & Nicholson, R. W.
System: The UNT Digital Library
Review of induction linac studies (open access)

Review of induction linac studies

The three major experimental activities are as follows: (1) The Single-Beam Transport Experiment (SBTE): A quadrupole transport system consisting of 5 matching lenses and 41 identical F-D lens pairs to test the stability, or otherwise, of transport of a high-current Cs/sup +1/ beam over a long distance; (2) The Multiple-Beam Experiment (MBE): An arrangement of long-pulse induction accelerating units between which are placed multiple-beam focussing arrays to transport 16 independent beams threading the same accelerating structure. The experiment is designed to simulate on a small scale as many as possible of the features to be encountered in the HTE; and (3) The High Temperature Experiment (HTE).
Date: January 1, 1984
Creator: Keefe, D.
System: The UNT Digital Library
Diffusion of molybdenum through H-451 graphite (open access)

Diffusion of molybdenum through H-451 graphite

Diffusion rates of molybdenum through graphite were determined in the temperature range of 2250/sup 0/C to 3300/sup 0/C. This work was conducted to characterize the behavior of fission products under an unrestricted core heat-up accident condition in a HTGR (High Temperature Gas Cooled Reactor).
Date: January 1, 1984
Creator: Lee, B. S.; Uneberg, G. & Sastre, C.
System: The UNT Digital Library
Effects of preionization by electron cyclotron heating in INTOR (open access)

Effects of preionization by electron cyclotron heating in INTOR

A model has been developed for the electron cyclotron heating (ECH) preionization and startup effects on the ISX-B tokamak. This model has satisfactory agreement with most of the observed phenomena on ISX-B. The model has been applied to INTOR under the assumption that sufficient power at a frequency commensurate with this device will be on hand. We have assumed the following parameters for INTOR: R = 5.3 m,a = 1.52 m, B/sub t/ = 6 T, and a maximum applied loop voltage of 35 V. The results suggest that moderate amounts of preionization will aid in the start up by allowing a reduction in the applied loop voltage, V/sub l/, will save some transformer flux, and will permit a more rapid current ramp. Massive preionization (greater than or equal to 1 MW) does not appear to be necessary.
Date: January 1, 1984
Creator: England, A. C. & Eldridge, D. C.
System: The UNT Digital Library
Comparison of BIASI and Columbia CHF correlations using BODYFIT-2PE (open access)

Comparison of BIASI and Columbia CHF correlations using BODYFIT-2PE

This paper compares the BIASI critical heat flux (CHF) correlation with the Columbia CHF correlation by using both the homogeneous equilibrium two-phase model with algebraic slip and the drift flux model in BODYFIT-2PE. All calculations were compared with the GE 3 x 3 CHF experiment. This comparison serves as a qualification process for the CHF correlations in the framework of BODYFIT-2PE.
Date: January 1, 1984
Creator: Chen, B. C. J.; Chien, T. H.; Sha, W. T. & Kim, J. H.
System: The UNT Digital Library