Reactor dynamics calculations for reactor with natural circulation of single phase coolant

Abstract

REACTOR DYNAMICS CALCULATIONS FOR REACTOR WITH NATURAL CIRCULATION OF SINGLE PHASE COOLANT* V. M. Selivanov, A. A. Gorev, I. I. Sidorova, and V. M. Gribunin UDC 621.039.56 The nonlinear mathematical model of the dynamics of the pr imary loop of a water-cooled watermoderated reactor with natural circulation of single-phase coolant is discussed. The solution of the nonstationary heat t ransfer equations is represented by an expansion in orthogonal Legendre polynomials with t ime-varying coefficients [1]. The introduction of this expansion makes it possible to reduce the entire system of equations describing the dynamics of the reactor to the form dx = Az + ] (x), where A is the (n • n) matrix of constant coefficients; x is the column vector of the phase coordinates; f(x) is the column vector of the nonlinear terms. The model under consideration is utilized in the case f(x) 0 to obtain the frequency response to an experimental arrangemenr simulating a reactor system [2]. It is pointed out that in accordance with the Gyftopoulos criterion [3], an increase in the negative temperature coefficient of reactivity (in absolute magnitude) will result in impaired system stability. Our calculations show that, in the presence of modest power perturbations, a reactor with natural coolant circulation and temperature feedback features is dynamically equivalent to a reactor with forced coolant circulation. 2. 3. LITERATURE CITED S. K. Sanathanan et a l . , Nucl. Sci. Engng., 23, No.2 (1965). V. M. Selivanov et a l . , At. Energ . , 27, 101-~969)o E. Gyftopoulos, Nucl. Sci. Engng., ~ No. 1 (1966)o NOTE ON OPTIMIZATION OF A STATIONARY REFLECTOR IN A PULSED FAST REACTOR B. I. Kuprin and E. P. Shabalin UDC 621.039.51 The pulsed neutron source method is highly recommended as a tool for solving many problems in neutron physics and in the physics of condensed media. Promising neutron sources for this line of research * Translated from Atomnaya ]~nergiya, Vol.31, No. 5, p. 505, November, 1971. Original article submitted submitted January 20, 1971; revision submitted April 22, 1971. t Translated from Ato~rmaya ]~nergiya, Vol. 31, No. 5, pp. 505-506, November, 1971. Original art icle submitted October 15, 1970. 9 1972 Consultants Bureau, a division of Plenum Publishing Corporation, 227 West 17th Street, New York, N. Y. 10011. All rights reserved. This article cannot be reproduced for any purpose whatsoever without permission o f the publisher. A copy of this article is available from the publisher for $15.00.