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Neutron Age in Graphite-Water Lattices.

Description: The Fermi age of thermal neutrons in a lattice containing both water and graphite in some sort of weighted average of the age in water and in graphite independently, with correction for volumes of non-moderating elements or voids. The correct weighting function has been in question during design calculations for the NPR. This paper presents a very simple and direct approach to the problem, resulting in a weighting equation which seems to be theoretically sound. Unfortunately, simple theories ca… more
Date: October 28, 1959
Creator: Simpson, D. E.
Partner: UNT Libraries Government Documents Department
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Two-Group Constants for Reactor Materials

Description: In order to facilitate reactor design studies a compilation of calculated two-group constants averaged over the infinite-medium flux produced by a fission source was made for approximately 80 materials of interest to reactor engineers. A comparison with available experimental age measurements is included. (auth)
Date: May 1, 1958
Creator: Stanley, Mary J.
Partner: UNT Libraries Government Documents Department
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A Test of the Age Theory (Part I)

Description: The Selengut-Goertzel and the P/sub 1/-approximations to the Boltzmann equation for the neutron slowing down process in a medium of finite extent are rewritten as integral equations over Placzek functions. In this form, the equations can be solved by iteration; also, in the asymptotic case, they permit the corresponding age equations to be read off directly. The first order nonasymptotic deviations of the flux from the age theoretical expressions are calculated. (auth)
Date: August 1, 1958
Creator: Sauer, A.
Partner: UNT Libraries Government Documents Department
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AN ORACLE CODE FOR CALCULATION OF FERMI AGES BY NUMERICAL INTEGRATION

Description: An oracle code was prepared for the calculation of Fermi ages by numerical integration. The code is designed to compute values of The effects of and fast and slow diffusion constants for two-group calculations from cross section data. The values of The effects of and the diffusion constants may be obtained for mixtures of any or all of sixteen elements. While the present tapes do not contain cross sections for sixteen different elements, cross sections may be changed in a simple and rapid manne… more
Date: April 10, 1956
Creator: Tobias, M.
Partner: UNT Libraries Government Documents Department
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A Pulsed Neutron Source Technique

Description: For a measurement of the diffusion constant D from the decay of the fundamental mode only, optimal dimensions of the pile are given, leading to a fast decay of the higher modes. Another method is discussed which makes use also of higher modes. Evaluation formulas and optimal pile dimensions for this method are derived. The amplitudes of the normal modes are calculated for different initial distributions of the neutrons by means of the Fermi age theory. The error introduced using Fermi age theor… more
Date: November 1, 1960
Creator: Siems, R. & Melissaropoulos, M.
Partner: UNT Libraries Government Documents Department
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CRITICALITY IN DUMP TANKS FOR HRE-3 BLANKET

Description: The possibility of criticality occurring in the HRE-3 slurry dump tanks was examined by estimating the critical concentration for an infinite system and comparing it to the concentrations which might conceivably occur with mixing please delete the above abstract no.5631==============
Date: January 31, 1958
Creator: Prince, B.E. & Rosenthal, M.W.
Partner: UNT Libraries Government Documents Department
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A MONTE CARLO CODE FOR THE TRANSPORT OF NEUTRONS

Description: A Monte Carlo code for the BM 704 computer was written to study the transport of neutrons in a uniform heterogeneous lattice of cylindrical fuel assemblies. Models of the geometric and physical processes are used to obtain the neutron age and migration area; the flux as a function of position, energy, and direction; and absorption data from which thermal utilization and the multiplication constant k may be calculated. (auth)
Date: December 1, 1959
Creator: Baxter, William V.
Partner: UNT Libraries Government Documents Department
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TWO-GROUP CALCULATIONS FOR A STEEL-WATER CRITICAL EXPERIMENT AND THE APPR

Description: Two-group constants have been prepared for a range of steel-water volume ratios. A calculation of critical mass and flux distribution has been made for an existing steelwater critical experiment. In order to check the experimental critical mass the age was increased. The effect of this adjustnnent on flux distribution was noted. The critical mass and flux distribution were calculated for the clean APPR critical experiment using the adjusted curve of age vs steel- water volume ratio. The calcula… more
Date: September 28, 1955
Creator: Gallagher, J G
Partner: UNT Libraries Government Documents Department
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SPECTRAL SHIFT CONTROL REACTOR BASIC PHYSICS PROGRAM-THEORETICAL ANALYSIS. PART II. BPG COMPUTER PROGRAM REPORT

Description: The BPG code was written to compute the criticality of reactors using all kinds or moderators, specifically including mixtures of H/sub 2/O and D/sub 2/ O. Since slowing down with hydrogen moderator is susceptible to exact calculation, and since the Fermi age equation accurately treats heavy moderators such as carbon, the important innovations in this code deal with the transition from light to heavy scatter, and particularly with the treatment of moderation by deuterium. Included in the descri… more
Date: January 1, 1962
Creator: de Coulon, G.A.G.; Gates, L.D. & Worley, W.R.
Partner: UNT Libraries Government Documents Department
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SPECTRAL SHIFT CONTROL REACTOR BASIC PHYSICS PROGRAM. Quarterly Technical Report No. 2, October-December 1960

Description: Basic physics parameters are being determined for lattices of slightly enriched fuel in moderators consisting of D/sub 2/O--H/sub 2/O mixtures of different concentrations. The principal effort was devoted to procurement and erection of equipment and materials needed for the critical experiments with D/ sub 2/O in the moderator, the exponential experiments, the hot exponential experiments, and the neutron age experiments. The erection of these facilities and the D/sub 2/O handling system was com… more
Date: October 31, 1961
Partner: UNT Libraries Government Documents Department
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Analytical calculations of neutron slowing down and transport in the constant-cross-section problem

Description: Aspects of the problem of neutron slowing down and transport in an infinite medium consisting of a single nuclide that scatters elastically and isotropically and has energy-independent cross sections were investigated. The method of singular eigenfunctions was applied to the Boltzmann Equation governing the Laplace transform (with respect to the lethargy variable) of the neutron flux. A new sufficient condition for the convergence of the coefficients of the expansion of the scattering kernel in… more
Date: April 1, 1978
Creator: Cacuci, D. G.
Partner: UNT Libraries Government Documents Department
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APPR-1 Axial Non-Uniform Burn Up--Initial Studies

Description: The control rod position in relation to reactor lifetime and the relative concentrations of U/sup 235/ and B/sup 10/ as a function of U burned were found by a modified 2-group theory using the adjusted age and a straight 2- group theory without fast multiplication or resonance capture. Results indicate that at 15% average burnup the flux shape and reactivity do not vary appreciably from that given by the uniform analysis. (F.S.)
Date: March 28, 1956
Creator: Fairbanks, F. B.
Partner: UNT Libraries Government Documents Department
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SPECTRAL SHIFT CONTROL REACTOR BASIC PHYSICS PROGRAM-THEORETICAL ANALYSIS. PART I. ANALYSIS OF EXPERIMENTS

Description: The data obtained in the series of SSCR experiments and the theoretical analysis of the results demonstrate the spectral shift control principle clearly. The critical assemblies show that considerably larger amounts of fuel can be loaded into a core moderated with a mixture of D/sub 2/O and H/sub 2/O than in one moderated with H/sub 2/O alone. The measured Cd ratios and the calculated neutron balances show that the excess reactivity associated with this extra mass is held up in the resonance ab… more
Date: March 1, 1962
Creator: Wehmeyer, D.B.; Doederlein, J.M.; Roach, K.E. & Wittkopf, W.A.
Partner: UNT Libraries Government Documents Department
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