Comparison study of reactivity meters based on the H_∞ optimal estimator with that based on the inverse kinetics equation

Reactivity estimation using the neutron flux signal has been carried out mainly by two methods, inverse kinetics equation method and Kalman filtering method. Recently a new estimation method has been proposed. The method is based on the H_∞ optimal estimation theory and can improve rather slow time response of the Kalman filtering method. The previous studies on these methods, however, have been reported independently. Hence, the information required to select the most suitable method seems to be insufficient, especially for those who plan to design a new reactivity meter. From this point of view, we carried out a comparison study on the important characteristics for reactivity measurement, noise filtering and time response, between H_∞ estimator and the inverse kinetics equation method derived by neglecting the time derivative of neutron flux. The comparison results show that the two types of reactivity meters have similar characteristics. Also some findings are shown for the tuning guidance of a parameter(γ) which determines the characteristics of H_∞ estimator to be designed. (author)