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On an analytical evaluation of the flux and dominant eigenvalue problem for the steady state multi-group multi-layer neutron diffusion equation

  • C. Ceolin , M. Schramm , B. E. J. Bodmann , M. T. Vilhena and S. de Q. B.Leite
Published/Copyright: November 4, 2014
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Abstract

In this work the authors solved the steady state neutron diffusion equation for a multi-layer slab assuming the multi-group energy model. The method to solve the equation system is based on an expansion in Taylor Series resulting in an analytical expression. The results obtained can be used as initial condition for neutron space kinetics problems. The neutron scalar flux was expanded in a power series, and the coefficients were found by using the ordinary differential equation and the boundary and interface conditions. The effective multiplication factor k was evaluated using the power method. We divided the domain into several slabs to guarantee the convergence with a low truncation order. We present the formalism together with some numerical simulations.

Kurzfassung

In dieser Arbeit lösen die Autoren die stationäre Neutronendiffusionsgleichung für mehrschichtige Bereiche und das Multi-Energiegruppenmodell. Das Verfahren, welches das Gleichungssystem löst, basiert auf einer Taylor-Reihenentwicklung und führt zu einem analytischen Ausdruck. Die erhaltenen Ergebnisse können als Anfangsbedingung für raumabhängige Neutronenkinetikprobleme verwendet werden. Der skalare Neutronenfluss wurde in eine Potenzreihe entwickelt und die Koeffizienten durch Verwendung der gewöhnlichen Differentialgleichung, der Randbedingungen und der inneren Anschlußbedingunen ermittelt. Der effektive Multiplikationsfaktor k wurde anhand der Potenzmethode bestimmt. Der Bereich wurde in mehrere Schichten unterteilt, um Konvergenz mit einem niedrigen Reihenabbruch zu garantieren. Der Formalismus wird zusammen mit einigen numerischen Simulationen vorgestellt.

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Received: 2014-05-12
Published Online: 2014-11-04
Published in Print: 2014-11-30

© 2014, Carl Hanser Verlag, München

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