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in subjects: "Neutron Flux"

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Neutron environment in d + Li facilities

A microscopic d + Li neutron yield model has been developed based upon classical models and experimental data. Using equations suggested by the Serber and evaporation models, a generalized least squares adjustment procedure generated angular yields for E/sub d/ to 40 MeV using the available experimental data. The HEDL-UCD experiment at E/sub d/ = 35 was used to adjust parameters describing the neutron spectra. The model is used to predict yields, spectra, and damage responses in the FMIT Test C… more

Date: January 1, 1980

Creator: Mann, F. M.; Schmittroth, F. & Carter, L. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation dosimetry through spectral definition

We have developed a fieldable instrumentation system for determining from measured flux spectra, both the neutron and gamma ray dose rate distributions associated with radioactive sources. This system includes the sensors, the computer-based data acquisition and analysis hardware, and the requisite software for unfolding the sensor response functions to obtain the flux spectra, and for folding the resultant flux spectra with appropriate flux spectrum-to-dose conversion factors. We use bismuth g… more

Date: January 1, 1985

Creator: Dowdy, E. J.; Moss, C. E.; Robba, A. A.; Evans, A. E.; Lucas, M. C.; Shunk, E. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Operating manual for the de Phanger precision long counter (PLC)

The setting up, calibration operation, characteristics, and problems of the precision long counter for neutron intensity measurements are discussed. (WHK)

Date: February 6, 1978

Creator: Slaughter, D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The Advanced Neutron Source

The Advanced Neutron Source (ANS) is a new user experimental facility planned to be operational at Oak Ridge in the late 1990's. The centerpiece of the ANS will be a steady-state research reactor of unprecedented thermal neutron flux ({phi}{sub th} {approx} 9{center dot}10{sup 19} m{sup -2}{center dot}s{sup -1}) accompanied by extensive and comprehensive equipment and facilities for neutron-based research. 5 refs., 5 figs.

Date: January 1, 1989

Creator: Hayter, J. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron flux enhancement at LASREF

The accelerator at the Los Alamos Meson Physics Facility produces a 1-mA beam of protons at an energy of 800 MeV. Since 1985, the Los Alamos Spallation Radiation Effects Facility (LASREF) has made use of the neutron flux that is generated as the incident protons interact with the nuclei in targets and a copper beam stop. A variety of basic and applied experiments in radiation damage and radiation effects have been completed. Recent studies indicate that the flux at LASREF can be increased by at… more

Date: January 1, 1991

Creator: Sommer, W. F.; Ferguson, P. D. & Wechsler, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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LWR-PV damage estimate methodology

A credible estimate of the pressure vessel lifetime due to neutron-induced embrittlement is studied. The first step toward this goal is the accurate prediction of fluence and neutron energy spectrum at the pressure vessel. This, in turn, is obtained from least squares unfolding techniques of dosimetry measurements at a surveillance position, transport calculations, and a translation of information obtained at the surveillance position to the damage position. Including a prototypic neutron field… more

Date: January 1, 1980

Creator: Wagschal, J.J.; Maerker, R.E. & Broadhead, B.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Argonne Code Center: benchmark problem book

This report is a supplement to the original report, published in 1968, as revised. The Benchmark Problem Book is intended to serve as a source book of solutions to mathematically well-defined problems for which either analytical or very accurate approximate solutions are known. This supplement contains problems in eight new areas: two-dimensional (R-z) reactor model; multidimensional (Hex-z) HTGR model; PWR thermal hydraulics--flow between two channels with different heat fluxes; multidimension… more

Date: June 1, 1977

Item Type: Report

Partner: UNT Libraries Government Documents Department

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User's guide for revised SPEC-4 neutron spectrum unfolding code

The SPEC-4 computer code was developed in the United Kingdom to solve the spectrum unfolding problem for spherical gas-filled proton-recoil neutron spectrometers. This report describes the ORNL version of SPEC-4 which has been applied to the analysis of data from the Tower Shielding Facility. Recent modifications are described which largely pertain to the graphical output routines. In addition, the input requirements are presented in considerable detail including suggestions and recommendations… more

Date: August 1, 1980

Creator: Johnson, J.O. & Ingersoll, D.T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Dynamic Simulation of Multi-Pass Pressurized Water Nuclear Power Plants by Analog Computer Techniques

A kinetic model of the primary loop of a multi-pass pressurized water reactor power plant is developed to evaluate, by analog computer techniques, the transient response characteristics under conditions of steam generator load and reactor control rod perturbations. Using the 2-pass 28 Mw(t) SM-2 reactor as a typical plant, transient behavior patterns are illustrated and examined for a variety of load inputs, variations in plant constants, and analog model simplifications. (auth)

Date: June 1, 1961

Creator: Brondel, J. O.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

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Radiation hardening of diagnostics

The world fusion program has advanced to the stage where it is appropriate to construct a number of devices for the purpose of burning DT fuel. In these next-generation experiments, the expected flux and fluence of 14 MeV neutrons and associated gamma rays will pose a significant challenge to the operation and diagnostics of the fusion device. Radiation effects include structural damage to materials such as vacuum windows and seals, modifications to electrical properties such as electrical cond… more

Date: January 1, 1991

Creator: Siemon, R.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Benchmark field study of deep neutron penetration

A unique benchmark neutron field has been established at the Lawrence Livermore National Laboratory (LLNL) to study deep penetration neutron transport. At LLNL, a tandem accelerator is used to generate a monoenergetic neutron source that permits investigation of deep neutron penetration under conditions that are virtually ideal to model, namely the transport of mono-energetic neutrons through a single material in a simple geometry. General features of the Lawrence Tandem (LATAN) benchmark field… more

Date: June 10, 1991

Creator: Morgan, J. F.; Sale, K. (Lawrence Livermore National Lab., CA (USA) ); Gold, R.; Roberts, J. H. & Preston, C. C. (Metrology Control Corp., Richland, WA (USA) )

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron flux measurements around PLT

Using Indium activation foils, the toroidal and poloidal neutron emission patterns were determined for PLT plasmas which include ICRF and neutral beam heating. The activities produced the /sup 115/In (n,n') /sup 115m/In reaction were determined by counting the 336 keV ..gamma.. line of the /sup 115m/In decay. This activation cross section falls just below 2.5 MeV so that the influence of scattered neutrons of degraded energies is reduced. From the magnitude of the activity, the absolute calibra… more

Date: September 1, 1980

Creator: Zankl, G.; Strachan, J.D.; Lewis, R.; Pettus, W. & Schmotzer, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

BOILING NUCLEAR SUPERHEATER (BONUS) POWER STATION. Supplementary Study. Extrapolation to Large Central Station Integral Nuclear Superheat Plant

An evaluation was made of the maximum size plant for which the BONUS reactor plant could serve as a realistic prototype and the design changes required to increase the size and characteristics for the present BONUS design such that it could serve as a realistic prototype for the largest feasible integral-superheat reactor power plant. (M.C.G.)

Date: October 31, 1962

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Analysis of the new GCFR upper and lower plenum flow-through shields

Analysis of the proposed GCFR upper and lower plenum flow-through shields has been performed using both discrete ordinate (DOT) and Monte Carlo (MORSE) methods. Several shields having one change of direction in the coolant path (chevron) and two changes of direction (herringbone) were investigated. The shields were modeled as unit cells with periodic boundary conditions. From plenum fluence calculations and design constraints at the reactor vessel liner, it was determined that all the shield co… more

Date: September 14, 1980

Creator: Cramer, S.N. (Oak Ridge National Lab., TN); Reed, D.A.; Emmett, M.B. & Rouse, C.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Reevaluation of ferritic steel DBTT data used in damage function analysis. [PWR; BWR]

Data used in damage function analysis of ferritic pressure vessel steels was improved in three areas: 1) errors in the fluences were corrected and all fluences renormalized on a common basis, 2) a physically realistic fluence dependence was used to extrapolate data to the desired property change level, and 3) improved a priori damage models were used to account for the energy dependence of damage. The above improvements eliminated spurious structure in the damage functions and reduced data scat… more

Date: January 1, 1979

Creator: Simons, R. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design of materials irradiation experiments utilizing spectral tailoring

The helium production to displacement per atom (He/DPA) ratio expected at the first wall of a fusion reactor for stainless steel alloys can be, within reasonable limits, reproduced in real time in fission reactors such as the Oak Ridge Research Reactor (ORR) due to the helium production characteristics of Ni(/sup 58/Ni + n/sub th/ ..-->.. /sup 59/Ni + n/sub th/ ..-->.. /sup 56/Fe + ..cap alpha..). The reproduction of the He/DPA ratio can be accomplished by intermittent modification of the therm… more

Date: January 1, 1980

Creator: Gabriel, T.A.; Lillie, R.A. & Bishop, B.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Use of additional fission sources or scattering sources to model inward axial leakages in fast-reactor analysis

When calculations of flux are done in less than three dimensions, bucklings are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. If the net leakage for a given energy group is outward (positive), the buckling is positive, and buckling methods work well. However, if the new leakage for a given energy group is inward (negative), the buckling is negative and can lead to numerical instabilities (oscillations in the iterative flux calculation). This rep… more

Date: October 1, 1981

Creator: Grimm, K. N. & Meneghetti, D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Supplementary neutron-flux calculations for the ORNL Pool Critical Assembly Pressure Vessel Facility

A three-dimensional Monte Carlo calculation using the MORSE code was performed to validate a procedure previously adopted in the ORNL discrete ordinate analysis of measurements made in the ORNL Pool Critical Assembly Pressure Vessel Facility. The results of these flux calculations agree, within statistical undertainties of about 5%, with those obtained from a discrete ordinate analysis employing the same procedure. This study therefore concludes that the procedure for combining several one- and… more

Date: January 1, 1982

Creator: Maudlin, P. J. & Maerker, R. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Ceramic and cermet targets

Use of isotopic materials as targets in high temperature environments, e.g., reactor cores, require that chemically stable forms of the isotopes be employed. Usually oxides are compatible with temperatures > 1600/sup 0/K, although some light element oxides exhibit some volatility at temperatures > 1300/sup 0/K. Especially in the case of heavy elements, the relatively low melting points of the metals, poor compatibility of the metals with encapsulation materials, and high chemical reactivity at … more

Date: January 1, 1979

Creator: Kobisk, E. H.; Quinby, T. C. & Aaron, W. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Substitute safety rods: Physics design and NTG calibration

Under certain assumed accident conditions, an SRS reactor may loose most of its bulk moderator while maintaining flow to fuel assemblies. If this occurs immediately after operation at power, components normally dependent on convective heat transfer to the moderator will heat up with the possibility of melting that component. One component at risk is the safety rod. Tests have shown that the current cadmium safety rod, which contains aluminum as well as cadmium, can fail at temperatures only sli… more

Date: July 1, 1991

Creator: Baumann, N.P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Two-Dimensional Neutronics Analysis of the Tokamak Fusion Test Reactor

The nuclear performance of the TFTR has been studied using two-dimensional radiation transport methods. The calculations were carried out using the two-dimensional discrete ordinates code DOT using S/sub 8/ angular quadrature and a P/sub 3/ expansion of the transport cross-section data. The cross sections were taken from the DLC-37 library and collapsed to a 35-neutron--21-gamma-ray energy group subset to facilitate the calculations. The TFTR and the concrete pillbox-shaped shield that surround… more

Date: January 1, 1977

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

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LOCA simulation in the NRU reactor: materials test-1

A simulated loss-of-coolant accident was performed with a full-length test bundle of pressurized water reactor fuel rods. This second experiment of the program produced peak fuel cladding temperatures of 1148K (1607/sup 0/F) and resulted in six ruptured fuel rods. Test data and initial results from the experiment are presented here in the form of photographs and graphical summaries. These results are also compared with the preceding prototypic thermal-hydraulic test results and with computer mo… more

Date: October 1, 1981

Creator: Russcher, G. E.; Marshall, R. K.; Hesson, G. M.; Wildung, N. J. & Rausch, W. N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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A fission source of radioactive heavy ions

Fission products, formed following neutron capture by a target located in the moderator of a high-flux reactor, may be mass separated to provide intense beams of radioactive nuclei. These will span a broad mass range whose form will depend on the target element and on the presence of epithermal neutrons. Shorter lived activities may be used for beams and those with a longer half-life may be collected to form radioactive targets. Neutron fluxes as high as 10{sup 14} neutrons cm{sup -2}s{sup -1} … more

Date: January 1, 1989

Creator: Hamilton, W.D. (Oak Ridge National Lab., TN (USA) Vanderbilt Univ., Nashville, TN (USA). Dept. of Physics and Astronomy)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

User's manual for the CDC-6600 version of AMPX

A CDC-6600 version of AMPX-I, the Oak Ridge National Laboratory's modular code system for generating coupled multigroup neutron--gamma libraries from ENDF/B data is described. The AMPX modules can generate multigroup neutron cross sections; generate multigroup gamma cross sections; generate gamma yields for gamma-producing neutron interactions; combine neutron cross sections, gamma cross sections, and gamma yields into ''couples sets;'' perform one-dimensional discrete-… more

Date: November 1, 1977

Creator: Pickard, P. S. & Vandevender, W. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department