Browsing by Author "Thompson, JJ"

Now showing 1 - 13 of 13
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    The critical size of a bare spherical reactor with anisotropic diffusion.
    (Australian Atomic Energy Commission, 1960) Thompson, JJ
    Using oblate spheroidal co-ordinates, the critical equation for a bare sphere with unequal axial and radial diffusion coefficients is derived. A two group model is used, with the degree of anisotropy the same in both groups.
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    Fuel element transient temperature studies.
    (Australian Atomic Energy Commission, 1961-11) Thompson, JJ
    A method is presented for the analysis of transient temperatures in a homogeneous circular cylindrical fuel element in a coolant channel with no axial conduction and no heat loss to the channel wall. In addition, some results are obtained for mean fuel element temperatures in power transients for a simpler model, but accounting for details of the axial coolant temperature distribution in the unsteady state.
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    Neutron diffusion formulae for homogeneous, axially symmetric, anisotropic media, for Monte Carlo applications.
    (Australian Atomic Energy Commission, 1961-07) Thompson, JJ
    Probability distributions and mean values relating to the diffusion of monoenergetic neutrons in a homogeneous but anisotropic medium are derived as basic studies of Monte Carlo calculations of radial and axial diffusion coefficients in heterogeneous systems. The generalisation of diffusion theory for application to anisotropic media is also discussed.
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    A note on the response of a circulating fuel reactor to random fluctuation in fuel concentration
    (Australian Atomic Energy Commission, 1956-11) Thompson, JJ
    A simplified model of a Uranium "Sodium" Beryllium circulating fuel reactor has been analysed to determine the root mean square power and temperature fluctuations due to random variations in the inlet fuel concentration. The results indicate that limits of ± 2% on the fuel concentration should reduce the mean square power excursion, due to this cause, to less than ½%. The calculations based on assumptions only, as regards the specification of the statistical nature of the fuel concentration, but the method can be used to obtain more realistic estimates when experimental evidence becomes available.
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    A note on thermo-elastic stress in axially symmetric anisotropic cylinders.
    (Australian Atomic Energy Commission, 1958-08) Thompson, JJ
    The equations of elasticity are used to determine the axially symmetric thermo-elastic stresses and displacements for an anisotropic cylinder with elastic symmetry under conditions of plane strain.
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    A preliminary kinetic study of a sodium-beryllium-uranium circulating fuel reactor
    (Australian Atomic Energy Commission, 1956-11) Thompson, JJ
    The initial response of a 1:100:2000 U-Na-Be Reactor, operating at a power density of 1200 cals/cc/sec, to a sudden change in the fuel concentration in the circulating carrier, has been calculated on the assumption of constant inlet temperature and no delayed neutrons. The result confirmed that the peak temperatures and power can be accurately calculated by ignoring the moderator temperature rise, and that the approach to the new steady state values is given by the solution of the linearized equations. The slow moderator heating implies that the departure from the steady state are still large when the carrier and fuel have completed one transit of the external circuit. The assumption that the mean temperature is the arithmetic peak but overestimates the maximum power and outlet temperature excursions by 15 1/2% and 7% respectively.
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    Response matrices in the double pN approximation of neutron transport theory
    (Australian Atomic Energy Commission, 1966-02) Thompson, JJ
    Relations are derived for reflection and transmission matrices of slabs in the double pN approximation which permit their evaluation without the determination of particular eigenvalues and eigenvectors for each problem. Invariance principles also lead to results analogous to those of Chandrasekhar in his classical theory of radiative transfer.
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    Some aspects of thermal neutron diffusion in non-uniform temperature moderator
    (Australian Atomic Energy Commission, 1959-07) Thompson, JJ
    The effect of non-uniform temperature on the Maxwellian distribution of thermal neutrons in a non-capturing moderator has been studied, using the heavy gaseous moderator approach. The results indicate that for typical temperature gradients in power reactors, the neutron temperature follows the moderator temperature with a negligible distortion of the spectrum, and that at the boundary between regions of different temperature, perturbations are restricted to a few centimeters.
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    Temperatures in a sphere with distributed source and variable surface heat transfer
    (Australian Atomic Energy Commission., 1964-08) Thompson, JJ
    An iterative perturbation theory solution is developed for a general, spherical, steady state heat conduction problem, to provide a basis for the estimation of hot spot factors for the fuel elements in a pebble bed reactor.
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    Theory and application of the double Pn method in slab geometry for isotropic neutron sources and scattering
    (Australian Atomic Energy Commission, 1963-04) Thompson, JJ
    A simple matrix formalism is developed to facilitate the application of the double PN method of spherical harmonics to multiple slab configurations, representative of some of the basic neutron transport problems in the theory of nuclear reactors. Special attention is given to the double P2 and P3 approximations, and the results of numerical computations are compared with known accurate results.
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    Two group theory for exploratory HTGC reactor calculation
    (Australian Atomic Energy Commission, 1958-08) Thompson, JJ
    A method is described for the manipulation of the solutions of two-group diffusion theory for a reflected sphere. Matrices are used to give a simple treatment useful for practical computation. The critical equation is formulated in terms of a second-order determinant only, which yields a measure of the amount of hypothetical absorber required between core and reflector for criticality and therefore a basis for a comparative study of systems. Sufficient equations are presented to enable both flux and adjoint flux distributions to be calculated. In addition, the basic results for the formulation of the critical equation for cylinders with either radical or end reflectors are given.
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    A two-group analysis of a finite fully reflected cylindrical reactor
    (Australian Atomic Energy Commission, 1960-12) Thompson, JJ
    A method is developed for the calculation of the critical size or effective multiplication constant of a fully reflected cylindrical reactor with a uniform core and uniform reflectors, using two-group theory. Solutions of the basic differential equations are superimposed, and boundary conditions satisfied by the use of orthogonal functions. The method appears suitable for a small digital computer.
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    A two-group, three-region, fully reflected cylindrical reactor program for the IBM 1620
    (Australian Atomic Energy Commission, 1962-12) Thompson, JJ; Godfrey, M
    This program was prepared as a pilot program for a larger computer and handles symmetrical reactors with core, side reflector and end reflectors, using 10 radial and 10 axial mesh regions. The output consists of the effective multiplication constant, the two flux distributions, and the fission source distribution. The extrapolated Liebmann process is used for the inner iterations.