Memorial-index-based inverse kinetics method for continuous measurement ofreactivity and source strength

A new neutron inverse kinetics method has been proposed to compute both rea ctivity and source strength using only noise-containing reactor power signa ls in a subcritical state. The method is applicable to cases when the effec tive source strength varies with a change in reactivity. A newly defined ki netics parameter, "Memorial Index", is introduced to detect properly the st art and end of a transient and to exclude time intervals that are ill-posed for numerical source strength estimation analysis based on the grouping me thod. Results for a numerical simulation analysis demonstrate that the revi sed analytic procedure incorporated with the Memorial Index enables one to continuously calculate precise values of both source strength and reactivit y during a complicated subcriticality transient.