26 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Neutron flux."  
Results: 1 - 24 next
open access

Studies of Axial-Leakage Simulations for Homogeneous and Heterogeneous EBR-II Core Configurations

Description: When calculations of flux are done in less than three dimensions, leakage-absorption cross sections are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. Since the neutron flux is axially dependent, the leakages, and hence the leakage-absorption cross sections, are also axially dependent. Therefore, to obtain axial flux profiles (or reaction rates) for individual subassemblies, an XY-geometry calculation delineating each subassembly has to be done a… more
Date: August 1985
Creator: Grimm, K. N. & Meneghetti, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

DIF3D: A Code to Solve One-, Two-, and Three-Dimensional Finite-Difference Diffusion Theory Problems

Description: The mathematical development and numerical solution of the finite-difference equations are summarized. The report provides a guide for user application and details the programming structure of DIF3D. Guidelines are included for implementing the DIF3D export package on several large scale computers. Optimized iteration methods for the solution of large-scale fast-reactor finite-difference diffusion theory calculations are presented, along with their theoretical basis. The computational and data … more
Date: April 1984
Creator: Derstine, K. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Use of Additional Fission Sources or Scattering Sources to Model Inward Axial Leakages in Fast-Reactor Analysis

Description: 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 1981
Creator: Grimm, K. N. & Meneghetti, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The DIF3D Nodal Neutronics Option for Two- and Three-dimensional Diffusion Theory Calculations in Hexagonal Geometry

Description: A nodal method is developed for the solution of the neutron-diffusion equation in two- and three-dimensional hexagonal geometries. The nodal scheme has been incorporated as an option in the finite-difference diffusion-theory code DIF3D, and is intended for use in the analysis of current LMFBR designs. The nodal equations are derived using higher-order polynomial approximations to the spatial dependence of the flux within the hexagonal-z node. The final equations, which are cast in the form of i… more
Date: March 1983
Creator: Lawrence, R. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Prediction of Thermal-Neutron Fluxes in the Bulk Shielding Facility from Lid Tank Shielding Facility Data

Description: Technical reports details how thermal neutron data from the Lid Tank Shielding Facility (LTSF) at Oak Ridge National Laboratory was used to predict fluxes for the larger Bulk Shielding Facility (BSF) by accounting for geometric differences and neutron self-attenuation within mockups. The study found predictions generally by 12 to 22% higher for distances closer than 60 cm from the reactor, but they are in essentially in agreement at larger distances.
Date: January 12, 1959
Creator: MacKellar, A. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

High Isotope Reactor Preliminary Design Study

Description: A comparison of possible types of research reactors for the production of trans-plutonium elements and other isotopes indicates that a flux-trap reactor consisting of a beryllium-reflected light-water-cooled annular fuel region surrounding a light-water island provides the required thermal neutron fluxes at minimum cost. The preliminary design of such a reactor was carried out on the basis of a parametric study of the effect of dimensions of the island and fuel regions heat removal rates, and f… more
Date: March 20, 1959
Creator: Lane, J. A.; Cheverton, R. D.; Claiborne, H. C.; Cole, T. E.; Gambill, W. R.; Gill, J. P. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Time-Dependent Neutron Flux for a Pulsed Subcritical Assembly

Description: Report discussing a study regarding the time-dependent neutron flux for a pulsed subcritical assembly. From abstract: "A two-group analysis has been applied to the transient behavior of the thermal flux in a subcritical assembly which has been given a short burst of fast neutrons."
Date: April 15, 1957
Creator: Fults, Stanley C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutron Flux and Spectra Measurements in the Sandia Pulsed Reactor Facility (SPRF)

Description: Introduction: Neutron measurements were made in the pulsed reactor building and on the safety screen of the pulsed reactor in order to determine the neutron yield of the reactor as a function of (1) distance from the reactor centerline, (2) direction in the reactor building, and (3) position on the reactor safety screen.
Date: January 1962
Creator: Buckalew, William H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Problem in the Conversion of Neutron Dose to Flux

Description: This report discusses the calculation involved in converting neutron dose to flux. In order to test conversion calculation methods, the flux entering the Oak Ridge National Laboratory Lid Tank and the water by the north face of the Oak Ridge National Laboratory Bulk Shielding Reactor was used.
Date: June 29, 1953
Creator: McMillan, D. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Further Critical Experiments on a Small Reactor of Enriched U-235 with Al-H₂O Moderator and Beryllium Reflector

Description: From introduction: "The purpose of the present report is to describe briefly certain improvements that have been made in the experimental facilities and to present the results of further measurements on critical masses and spatial neutron flax distributions in Be reflected reactors having square and thin slab geometries."
Date: August 17, 1948
Creator: Martin, A. B. & Mann, M. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Evaluation of Resonance Capture Approximations

Description: The program KRUDE, which solves the slowing down and adjoint equations for a mixture of resonance and nonresonance isotopes in an infinite homogeneous medium, was used to evaluate some resonance capture approximations (variational and successive) that use linear combinations of narrow and wide resonance fluxes. Results obtained for resonance capture in the 291-ev resonance of Zr/sup 91/ and the 192-ev resonance of U/sup 238/ are compared, and three methods for including Doppler effects in the v… more
Date: December 16, 1963
Creator: Edgar, K. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Application of the Variational Method to the Calculation of the Time Dependence of the Neutron Flux in Small Pulsed Slabs, Cylinders and Spheres

Description: The variational method is applied to the monoenergetic time dependent transport equation to obtain a simple relation for the asymptotic decay constant in small pulsed assemblies. The results indicate that flat trial functions may be a reasonable representation of the flux distributions in the thin slab limit. This approach is superior to many of the usual transport approximations.
Date: December 16, 1963
Creator: Judge, F. D. & Daitch, Paul B. (Paul Bernard), 1925-
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Bucklings, Disadvantage Factors, and [Delta]28 Measurements in Some Undermoderated Slightly Enriched Cores

Description: The reactivity lifetime of a water-moderated, thermal, power reactor using a low enrichment fuel is, in part, dependent upon the conversion ratio. The High Conversion Critical Experiment (Hi-C) was initiated at Argonne to extend the rage of investigations with light water moderated, slightly enriched, oxide-fueled cores. Bucklings were obtained from the clean critical core size and reflector savings values. The so-called "integral" technique was used to measure the disadvantage factor.
Date: 1963
Creator: Baird, Q. L. & Boynton, A. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Radiation Bursts in U235 Solutions

Description: From abstract: "Calculations are made of the magnitude of the radiation bursts that can occur in a mixer-settler and in a large tank containing U235 solution if the concentration gets out of control. Various rates of increase in concentration are studied and various restraints are imposed on the expansion of the systems. The neutron kinetics equations, with five groups of delayed neutrons, and the equations relating the neutron flux to the pressure and volume of the gas formed by fission fragme… more
Date: September 1958
Creator: Clark, Hugh K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fluxes and Reaction Rates in the Presence of Interferring Resonances

Description: The effects of competition between resonances of different isotopes were investigated. Flux and reaction rate calculations on a Pu/sup 239/-- U/sup 238/ system revealed that U/sup 238/ exhibits both self-shielding and interference effects, the latter becoming noticeable at enrichment of a few per cent. Gold activation was also found to be depressed by the presence of U, but was insensitive at low enrichment values, Investigation of the Pu/sup 239/ resonance integral showed an asymmetric effect … more
Date: November 1963
Creator: Kelber, Charles N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Asymptotic Neutron Spectra in Multiplying Media

Description: Asymptotic low energy neutron spectra have been measured for two multiplying systems. The reentrant hold spectrum (scalar flux) and the surface leakage spectrum were obtained for both assemblies using the pulsed-source chopper technique at the RPI linear accelerator.
Date: November 1963
Creator: Slovacek, R. E.; Fullwood, R. R.; Gaerttner, Erwin Rudolf, 1911- & Bach, D. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Diffusion Parameters of Water for Various Scattering Kernels

Description: Abstract. Some diffusion parameters of water are computed with various thermal-neutron scattering laws. It is found that the diffusion cooling coefficient, in particular, is reasonably sensitive to the scattering law, but that the diffusion cooling coefficients predicted by the Radkowsky and Nelkin kernels are in fortuitious agreement. The coefficients computed for the Nelkin kernel, when treated in a manner consistent with the way in which experimental data are treated, are in reasonable agree… more
Date: August 16, 1963
Creator: Calame, Gerald P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Argonaut Automatic Flux Controller Design Report

Description: Report issued by the Argonne National Laboratory over design studies conducted on Argonaut reactors for training and research purposes. As stated in the abstract, "the design presented in the form of a steady-state analysis based upon the small-signal linearization of the reactor kinetics transfer function. The measured controller performance and construction details of the equipment is given" (p. 7). This report includes tables, illustrations, and photographs.
Date: January 1960
Creator: Gerba, A., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Calculation of the Gamma-Ray Spectrum of the Bulk Shielding Reactor

Description: A calculation was performed to determine the high energy portion of the gamma-ray flux at the surface of the uranium-aluminum BSF reactor. The flux was considered to consist entirely of the un-collided flux plus the Compton scattered flux. The four sources of primary gamma rays included in the calculation were prompt fission gamma rays, capture gamma rays from aluminum, capture gamma rays from uranium, and fission-product decay gamma rays. These sources were divided into four energy groups. Alt… more
Date: July 31, 1957
Creator: deSaussure, Gerard
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen