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Nuclear Science, IRE Transactions on

Issue 1 • Date March 1957

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Displaying Results 1 - 14 of 14
  • Table of contents

    Page(s): c1
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    Freely Available from IEEE
  • IRE Professional Group on Nuclear Science

    Page(s): c2
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    Freely Available from IEEE
  • Ionization Chamber Survey Instrument

    Page(s): 1 - 2
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    A wide range survey instrument is described. Ranges are 20 mr/hour to 20 r/hour full scale. The thin plastic ionization chamber is easily replaced if contaminated. A three-tube, negative feedback circuit with low battery drain is used. The input resistor selector switch is a new design with high insulation. It is nonmicrophonic and does not cause transients when changing ranges. View full abstract»

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  • Regulation of the Individual Dynode Voltages for Photomultiplier Tubes

    Page(s): 3 - 11
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    An individual dynode voltage regulating system has been devised which can be mounted on the phototube socket in much the same manner as, and with no more difficulty than, the common bleeder resistance voltage divider. Two types of these regulators have been investigated; the first using silicon diodes, and the second using NE-2 neon tubes. The statistical spread of beta-ray counts was reduced from (±) six standard deviations to nearly the normal spread of (±) three standard deviations. The photometric sensitivity range of linearity was increased by an order of magnitude. View full abstract»

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  • Nuclear Reactor Start-Up Simulation

    Page(s): 11 - 14
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    This paper describes the problem of simulating nuclear reactor start-up with an electronic analog computer. The reactor kinetic equations are discussed and the range that their solution must cover is defined. Source range simulation and alternate methods of simulating the intermediate range are presented. The use of reactor period signal in the intermediate range is described. In the power range, which includes a representation of the heating and temperature effects, the inherent advantages of a pressurized water reactor are outlined. The portion of the start-up simulation which applies to nuclear reactors in general is summarized. The areas of modification necessary for the simulation of other than pressurized water reactors is outlined. View full abstract»

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  • Frequency Response Measurements of Power Reactor Characteristics

    Page(s): 15 - 19
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    The problem of measuring fundamental characteristics of an inherently stable power-producing reactor is described. It is noted that, in the power range of operation of such a plant, reactivity is a function not only of control rod position, but also of power itself. The mechanism of the latter effect involves the variòus inherent coefficients of reactivity. The result is that conventional, low-power methods can be used neither to obtain rod calibrations, nor to determine temperature coefficient in the very range of operation where these characteristics assume importance. It is shown that a number of parameters including those mentioned above may be measured by effecting small sinusoidal perturbations in control rod position over a range of frequencies. The resultant frequency responses are analyzed by the familiar transfer function-block diagram method. Certain inherent advantages of the method are cited including: 1) Ability to separate effects which predominate in different frequency regions. 2) Improved reproducibility of power range measurements. Disturbances induced by steam plant changes, inherently nonreproducible, are avoided. 3) Good accuracy of data. The measurement replies primarily on good differential accuracy, easier to obtain from operational instrumentation than good absolute accuracy. 4) Ability to check data reproducibility by obtaining several cycles of data at each frequency. A brief description is included of the manner by which the technique is used to determine the following nuclear properties: 1) Perturbing rod calibration, 2) Temperature coefficient of reactivity, 3) Neutron generation lifetime, 4) Fractional production of delayed neutrons, 5) Mean delayed neutron decay constant. View full abstract»

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  • A Self-Checking Radiation Monitor

    Page(s): 19 - 25
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    A self-checking system of circuits is expected to provide a new high in operational reliability for the set of radiation monitors described. Developed under sponsorship of the Bureau of Ships, these monitors can readily be adapted for application in any nuclear installation where radiation monitoring must be performed. Three basic channels are provided to measure accurately the gamma radiation in the range from 1 to 1000 mr/hr, the thermal neutron flux from 20 to 20,000 thermal neutrons/cm2 sec, and the air-particle concentration from 10-9 to 10-6, ¿C/cm3 or from 10-8 to 10-5 ¿C/cm3. Checking of each channel is performed by periodically (and automatically) placing a small radioactive source next to the detecting element in each channel. This results in a signal near the maximum range of each channel. During such checks, the alarm-indicating circuit is disconnected and the channel output applied to a comparator circuit; there will result a "circuit fault" indication if any part of the signal-handling or the checking circuits has failed. The philosophy and the limitations of the checking scheme are discussed. The calibration of the air-particle channel is in terms of a specific isotope. Calibrations for other isotopes can be prepared. Shielding is applied to the detecting element in the air-particle channel in order to minimize counts due to the ambient gamma background. The gamma detector has shielding to equalize its response to radiation at energies between 80 kev and 2 mev. View full abstract»

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  • The Relative Stability of Boiling and Pressurized Light Water Moderated Reactors

    Page(s): 25 - 29
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    This paper compares the stability of a given heterogeneous core when operated with a pressurized or subcooled water cooling system in which the power is removed by boiling. In order to provide a basis for comparison the following assumptions are made: 1) reactor power is the same in both cases, 2) the core geometry is the same in both cases, 3) in the case of subcooled operation, coolant flow rate and core inlet temperature are held constant, and 4) in the case of boiling operation reactor pressure is constant. Assumptions 3) and 4) imply that the load equals power generated at all times. The core geometry and the values of the various system parameters are taken from published literature wherever possible. It is shown that the results of this analysis are readily predictable from physical reasoning. View full abstract»

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  • Designing Heterogeneous Reactors for Stability

    Page(s): 30 - 33
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    A study of the nonlinear kinetics of heterogeneous reactors can lead to basic design criteria which are useful in designing stability into a given reactor. The design of most reactors is usually based upon other physical parameters such as reactivities, heat transfer surfaces, metallurgical conditions, and operating lifetimes. The question of reactor stability is often deferred on the design schedule until these other parameters have so closely bounded the design that only incidental changes are possible. It is fortunate that many reactors are naturally stable over wide ranges of design conditions. Nonlinear kinetics have been examined in two ways in the past. The first method is to modify the basic reactor kinetic equations to include the effects of temperature, pressure, or poisoning. Solutions of these equations generally can be obtained with some approximation being needed. The second method consists of obtaining the transfer function of a simple reactor and modifying the characteristics of this reactor by feedback networks. The first method has been used successfully by Weinberg and Ergen for homogeneous reactors and by Lipkin and others for heterogeneous reactors. The second method is an engineering one which is capable of giving considerable information over a wide range of variables and will be used in this paper with suitable approximation to examine the stability of heterogeneous reactors. View full abstract»

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  • Electronics at the French Atomic Energy Commission

    Page(s): 34 - 39
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    This paper gives a description of the organization and functioning of the Electronic Division of the Atomic Energy Commission of France. The Division is organized into four sections, Physical Electronics, General Electronics, Industrial Electronics, and Radioactive Isotopes Measurement. The sections are subdivided into groups. There are approximately 200 persons in the Division. Descriptions are given in this paper of typical development projects and method of operation. Some examples of interesting instruments are given together with a brief description of their operation. View full abstract»

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  • Design and Use of the Reactivity Computer

    Page(s): 40 - 48
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    The basic, underlying variable of reactor control is the reactivity. We may regard the reactivity as a measure of the deviation from equilibrium of the neutron balance in a reactor. Or more precisely, we may define the reactivity as the average excess number of neutrons produced per fission that cause further fission, "excess" being the number over and above the one-neutron-per-fission that is required to maintain a self-sustaining fission reaction. Reactor control may be described as the process of changing the neutron environment within a reactor so as to produce momentary excursions in the reactivity from its equilibrium value of zero. The measurement of these excursions in reactivity is the subject of this paper. Two electrical analog computer designs are described which compute the reactivity from electrical signals which are provided by conventional reactor instrumentation systems. One computer utilizes a neutron flux input signal; the other employs a log-rate (of neutron flux) input signal. Applications of these computers in control system analysis and reactor instrumentation are discussed. View full abstract»

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  • Radioactive tracer study of sewage field in Santa Monica bay

    Page(s): 49 - 50
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    In a unique experiment just completed in Santa Monica Bay, CA, USA, radioactive isotopes were successfully used to trace dispersion of sewage effluent in ocean waters. The results help to establish proper design procedures to insure against beach pollution in a current expansion of the Los Angeles sewage system. To effect the experiment twenty curies of scandium-46 were mixed with sewage effluent and discharged into the sea. Scientists aboard a laboratory ship then took radioactive measurements over a wide area to determine dilution rate and direction of diffusion. View full abstract»

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  • Information for authors

    Page(s): 50a
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  • Institutional listings

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Aims & Scope

This Transactions ceased production in 1962. The current retitled publication is IEEE Transactions on Nuclear Science.

Full Aims & Scope