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in subjects: "Radiation Transport"

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Point kernel versus radiation transport for iron deep penetration problems

The purpose of this study was to determine the relative merits and adequacy of the QAD-CG and QAD-CGGP point kernel codes for spent fuel shielding problems by comparing gamma dose results with those of several radiation transport codes - DOT IV, MORSE-SGC, XSDRNPM-S, and MCNP. An intercomparison of results from the radiation transport codes was also of secondary interest. The problem considered was an R-Z spent fuel cask model consisting of a homogenized source region (UO/sub 2/ fuel + basket) … more

Date: January 1, 1987

Creator: Broadhead, B.L. & Parks, C.V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Mechanisms of fast neutron penetration in thick layers of sodium

A series of computer experiments was carried out to elucidate the penetration mechanisms of fast neutrons through thick layers of sodium such as occur in LMFBR designs. As a one-dimensional approximation of the actual situation, the calculations concentrated mainly on the flux 5 meters from a plane isotropic fission source in an infinite sodium medium. Most of the transport calculations were made with the moments-method code BMT with a 496-energy point grid. Previously developed methods for rec… more

Date: January 1, 1975

Creator: Huang, L. Y.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Recent results from DIII-D and their implications for next generation tokamaks

Recent results from the DIII-D tokamak have provided significant contributions to the understanding of many of the elements of tokamak physics and the application of this understanding to the design of next generation devices including ITER and CIT. The limitations of magnetohydrodynamics stability on the values of plasma beta (the ratio of kinetic pressure to the containing pressure of the magnetic field) that can be attained has been experimentally demonstrated and found to be described by ex… more

Date: July 1, 1990

Creator: Luxon, J. L.; Bramson, G.; Burrell, K. H.; Brooks, N. H.; Callis, R. W.; Carlstrom, T. N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Polarization dependence of magnetic neutron scattering

The polarization dependence of magnetic neutron scattering is shown to depend on the imaginary part of the symmetric generalized susceptibility, chi/sub s//sup ..cap alpha beta../ = /sup 1///sub 2/(chi/sup ..cap alpha beta../(Q,..omega..) + chi/sup ..beta cap alpha../(Q,..omega..), as well as on the real part of the antisymmetric susceptibility, chi/sub a//sup ..cap alpha beta../ = /sup 1///sub 2/(chi/sup ..cap alpha beta../(Q,..omega..) - chi/sup ..beta cap alpha../(Q,..omega..)). The latter t… more

Date: January 1, 1976

Creator: Blume, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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E Division activities report, FY 1976

Some of the activities in E (Experimental Physics) Division are described. E Division carries out basic and applied research in atomic and nuclear physics as well as in material and biomedical sciences, centered around the Laboratory's four major accelerators. Experiments are grouped under the headings of neutron, photon, and charged-particle interactions. Investigations in this past year involved fission cross sections, nuclear reactions with neutrons, charged particles and gamma rays, in… more

Date: September 24, 1976

Creator: Barschall, H. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Radionuclide inventories for short run-time space nuclear reactor systems

Space Nuclear Reactor Systems, especially those used for propulsion, often have expected operation run times much shorter than those for land-based nuclear power plants. This produces substantially different radionuclide inventories to be considered in the safety analyses of space nuclear systems. This presentation describes an analysis utilizing ORIGEN2 and DKPOWER to provide comparisons among representative land-based and space systems. These comparisons enable early, conceptual consideration… more

Date: October 22, 1992

Creator: Coats, Richard L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Studies of metal: semiconductor interfaces in catalysis and energy conversion. Annual report, June 15, 1980-June 14, 1981

It was shown that CO hydrogenation reactions can be performed reproducibly on a small area well characterized Ni (111) single crystal using an isolation cell technique. The activation energy for methane production (24.7 kcal/mole) and other hydrocarbon product distribution are in excellent agreement with the literature. It was demonstrated that Ni dispersed onto TiO/sub 2/ (100) acquires a negative charge and that the Ni/TiO/sub 2/ (100) exhibits a methanation activity at least 4 times that of … more

Date: February 1, 1981

Creator: Chung, Y W

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Savannah River Site K-Reactor Probabilistic Safety Assessment

This report gives the results of a Savannah River Site (SRS) K-Reactor Probabilistic Safety Assessment (PSA). Measures of adverse consequences to health and safety resulting from representations of severe accidents in SRS reactors are presented. In addition, the report gives a summary of the methods employed to represent these accidents and to assess the resultant consequences. The report is issued to provide useful information to the U. S. Department of Energy (DOE) on the risk of operation of… more

Date: December 1, 1992

Creator: Brandyberry, M. D.; Bailey, R. T.; Baker, W. H.; Kearnaghan, D. P.; O`Kula, K. R.; Wittman, R. S. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Influence of point defects on grain boundary diffusion in oxides

The influence of point defects on grain boundary diffusion of Co ions in NiO was studied using polycrystalline films and bicrystals. Grain boundary diffusion was studied at 750 C at oxygen partial pressure. Two diffusion regions were found. At low oxygen pressures, extrinsic diffusion was observed. Above oxygen pressure of 10{sup {minus}7}, influence of intrinsic point defects was detected. It was determined that grain boundary diffusion was > 3 orders of magnitude faster than volume diffusion.… more

Date: March 15, 1991

Creator: Stubican, V. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Three-dimensional calculations of neutron streaming in the beam tubes of the ORNL HFIR (High Flux Isotope Reactor) Reactor

The streaming of neutrons through the beam tubes in High Flux Isotope Reactor at Oak Ridge National Laboratory has resulted in a reduction of the fracture toughness of the reactor vessel. As a result, an evaluation of vessel integrity was undertaken in order to determine if the reactor can be operated again. As a part of this evaluation, three-dimensional neutron transport calculations were performed to obtain fluxes at points of interest in the wall of the vessel. By comparing the calculated a… more

Date: January 1, 1988

Creator: Childs, R. L.; Rhoades, W. A. & Williams, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Predicted Bremsstrahlung generation by energetic electron beams

The CYLTRAN photon/electron Monte Carlo code has been employed to predict Bremsstrahlung generation by monoenergetic electron beams from 10 to 1000 MeV. The forward-directed Bremsstrahlung intensity is investigated as a function of beam energy converter thickness, and material. At high energies, the forward extraction efficiency is maximized by using converters that are about 0.1-electron ranges thick. The largest intensities are attained with low-Z converter materials such as beryllium. Becaus… more

Date: January 1, 1991

Creator: Faehl, R. J.; Snell, C. M. & Keinigs, R. K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Inherent limitations and current status of the unresolved resonance treatment

The two general methods for representing the behavior of the unresolved resonances and the limitations of these methods are discussed. Possible solutions to the problem are considered. 17 references. (WHK)

Date: January 1, 1984

Creator: Hwang, R.N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Integral Experiments for Fusion Reactor Design: Analysis

Integral experiments that measure the energy spectra of neutrons and gamma rays due to the transport of approx. 14 MeV D-T neutrons through laminated SS-304 and borated polyethylene shield assemblies have been performed. Measured and calculated energy spectra and integrated flux distributions are compared for a typical shield assembly as a function of detector location.

Date: January 1, 1979

Creator: Santoro, R. T.; Alsmiller, R. G., Jr.; Barnes, J. M. & Oblow, E. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Monte Carlo calculations of 14-MeV neutron multiplication in thick beryllium assemblies and comparison with experimental results

Integral experiments performed at the Institute for Reactor Development at Juelich, West Germany, have raised doubts about the adequacy of current nuclear data and calculational methods in predicting neutron multiplication and leakage from beryllium assemblies bombarded with 14-MeV neutrons. Experimental values of inferred neutron multiplication were reported to be less than calculated values by approx. 25%. We have performed calculations of the experiments using the TART Monte Carlo code. The … more

Date: February 29, 1984

Creator: Doyle, J. C. Jr. & Lee, J. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Doppler effect measurements on solid and liquid Sn. [24 keV]

Neutrons at 24 keV were used to measure the integrated neutron transmission of relatively thick tin samples as a function of thickness and temperature. The effective total cross sections are plotted and discussed as a function of the Doppler effect, temperature resonance self-shielding, and thickness. 6 references. (JFP)

Date: January 1, 1978

Creator: Tsang, F.Y. & Brugger, R.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurements of the charge state distribution and transport of iron impurity ions in TFTR plasmas by a multi-chord x-ray crystal spectrometer

The radial charge-state distribution and transport of iron impurity ions in ohmically heated TFTR plasmas has been determined by a detailed comparison of the x-ray spectra obtained from a high resolution multi-chord crystal spectrometer with the predictions from plasma modeling calculations. 9 refs., 3 figs., 1 tab.

Date: April 1, 1989

Creator: Bitter, M.; Hsuan, H.; Hill, K. W.; Hulse, R. A.; Von Goeler, S.; Johnson, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

MELCOR Accident Consequence Code System (MACCS)

This report describes the MACCS computer code. The purpose of this code is to simulate the impact of severe accidents at nuclear power plants on the surrounding environment. MACCS has been developed for the US Nuclear Regulatory Commission to replace the previous CRAC2 code, and it incorporates many improvements in modeling flexibility in comparison to CRAC2. The principal phenomena considered in MACCS are atmospheric transport, mitigative actions based on dose projection, dose accumulation by … more

Date: February 1, 1990

Creator: Chanin, D. I.; Sprung, J. L.; Ritchie, L. T. & Jow, Hong-Nian

Item Type: Report

Partner: UNT Libraries Government Documents Department

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A computer code to estimate accidental fire and radioactive airborne releases in nuclear fuel cycle facilities: User's manual for FIRIN

This manual describes the technical bases and use of the computer code FIRIN. This code was developed to estimate the source term release of smoke and radioactive particles from potential fires in nuclear fuel cycle facilities. FIRIN is a product of a broader study, Fuel Cycle Accident Analysis, which Pacific Northwest Laboratory conducted for the US Nuclear Regulatory Commission. The technical bases of FIRIN consist of a nonradioactive fire source term model, compartment effects modeling, and … more

Date: February 1, 1989

Creator: Chan, M.K.; Ballinger, M.Y. & Owczarski, P.C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Calculation of Neutron and Gamma Ray Energy Spectra for Fusion Reactor Shield Design: Comparison with Experiment

Integral experiments that measure the transport of approx. 14 MeV D-T neutrons through laminated slabs of proposed fusion reactor shield materials have been carried out. Measured and calculated neutron and gamma ray energy spectra are compared as a function of the thickness and composition of stainless steel type 304, borated polyethylene, and Hevimet (a tungsten alloy), and as a function of detector position behind these materials. The measured data were obtained using a NE-213 liquid scintill… more

Date: August 1, 1980

Creator: Santoro, R. T.; Alsmiller, R. G., Jr.; Barnes, J. M. & Chapman, G. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Nodal methods for discrete-ordinates transport problems in (x,y) geometry

A nodal method has been developed for improved spatial differencing of the discrete-ordinates form of the x,y geometry transport equation. In applying this method, spatial flux expansions are assumed along the edges of each solution node (mesh cell), and flux and source expansions are assumed in the interior of the node. Nodal method schemes are thus identified by the expansions used for node edges and node interior. Nodal schemes assuming constant-constant, constant-linear, and four forms of l… more

Date: January 1, 1981

Creator: Walters, W. F. & O'Dell, R. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron filters for producing monoenergetic neutron beams

Neutron transmission measurements have been made on high-purity, highly-enriched samples of /sup 58/Ni (99.9%), /sup 60/Ni (99.7%), /sup 64/Zn (97.9%) and /sup 184/W (94.5%) to measure their neutron windows and to assess their potential usefulness for producing monoenergetic beams of intermediate energies from a reactor. Transmission measurements on the Los Alamos Sc filter (44.26 cm Sc and 1.0 cm Ti) have been made to determine the characteristics of the transmitted neutron beam and to measure… more

Date: January 1, 1982

Creator: Harvey, J.A.; Hill, N.W. & Harvey, J.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Measurement of the neutron total cross section of natural magnesium from 9 keV to 39 MeV. [Tables, resonance]

The neutron transmission through a 5.09-cm sample of natural magnesium was measured for neutron energies between 9 keV and 39 MeV. The Oak Ridge Electron Linear Accelerator (ORELA) was used to provide the neutrons, which were detected at the 200-m flight path by a NE-110 proton recoil detector. The experimental results are tabulated and compared with the total cross section in the ENDF/B-IV file for magnesium.

Date: June 1, 1978

Creator: Larson, D.C.; Harvey, J.A.; Hill, N.W. & Weigmann, H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Monte Carlo photon benchmark problems

Photon benchmark calculations have been performed to validate the MCNP Monte Carlo computer code. These are compared to both the COG Monte Carlo computer code and either experimental or analytic results. The calculated solutions indicate that the Monte Carlo method, and MCNP and COG in particular, can accurately model a wide range of physical problems.

Date: January 1, 1991

Creator: Whalen, Daniel J.; Hollowell, David E. & Hendricks, John S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Irradiation experiment for lithium ceramics

Solid breeder materials are required in D-T fusion reactor blankets to convert fusion neutrons to tritium and thermal energy while providing some neutron shielding for the magnets. Lithium compounds such as Li/sub 2/O, LiAlO/sub 2/, Li/sub 4/SiO/sub 4/ and Li/sub 2/ZrO/sub 3/ have been proposed as solid breeder materials. Tritium is necessary to maintain the fuel supply for the D-T fusion reaction. No high burnup irradiation performance data is available for these materials in a neutron environ… more

Date: March 1, 1982

Creator: Hollenberg, G.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department