Estimation of shutdown reactivity in power reactor: comparative study of inverse point kinetics and Kalman filtering

Measurement and on-line display of reactivity are of great help in calibration of reactivity control and safety devices and planning of suitable actions during the reactor operation. Reactivity can be estimated by the traditional Inverse Point Kinetics (IPK) method or by a recently developed Kalman filtering (KF) based method. The KF based reactivity estimation proves superior to IPK method, especially in subcritical operating regime which is characterized by very low neutron flux level and large fluctuations in it. In this article, a comparison in the performance of the reactivity estimation by methods based on KF and IPK has been made by analysis of data collected from power reactors. The KF based approach has been found to yield higher accuracy, noise suppression and robustness than IPK based approach. (author)