A MODIFIED PROCEDURE FOR THE EVALUATION OF PULSED SOURCE EXPERIMENTS IN SUBCRITICAL REACTORS

The difficulties encountered in the evaluation of pulsed source experiments in subcritical reactors are reviewed briefly as an introduction to the description of a modified procedure which avoids these difficulties. By using the physical information obtained about the delayed neutrons, instead of rejecting them as background, one can find both reactivity and generation time from the very same pulsed source measurement. If measurements are begun only after the delayed neutron precursors have attained their equilibrium, the reactivity and reduced generation time of the prompt neutrons can be given by very simple approximations. Results obtained in recent experiments using the pulsed source method, the modified source jerk method, and the modified pulsed source method are compared. (J.S.R.)