The transfer function of a steadily diverging reactor

Abstract

In the design of automatic control systems which operate a diverging reactor, e.g. automatic start-up systems, a knowledge of the transfer function of the recctor is required. General expressions for the gain and phase shift of a steadily diverging reactor as functions of frequency are derived. Numerical values have been computed for a reactor with six groups of 235U delayed neutrons. “Doubling times” of 1, 5 and 20 sec and mean neutron lifetimes of 10 −3, 10 −4 and 10 −6 sec have been considered and results for these values are shown graphically. The results show that the transfer function of a diverging reactor is significantly different from that of a reactor in the steady state. The differences are of such a nature as to decrease the phase and gain margins of stability of the control system. The additional stability margins required can be found from the graphs.