Reactor Theory (Reactor Operations)DOE-HDBK-1019/2-93SUBCRITICAL MULTIPLICATIONSummaryThe important information in this chapter is summarized below.Subcritical Multiplication SummarySubcritical multiplication is the effect of fissions in the fuel increasing the effective source strength of a reactor with a k_{eff} less than one.Subcritical multiplication factor is the factor that relates the source level to thesteady-state neutron level of the core.The steady-state neutron level of a subcritical reactor can be calculated based onthe source strength and k_{eff} using Equation (4-3).N S11 k_{eff}The count rate expected in a subcritical reactor following a change in reactivitycan be calculated based on the initial count rate, initial k_{eff}, and amount ofreactivity addition using Equation (4-4).CR_{1}CR_{2}1 k_{2}1 k_{1}1/M plots can be used to predict the point of criticality.Rev. 0NP-04Page 9