Reactivity Estimation Based on an Extended State Observer of Neutron Kinetics

Reactivity is a key physical parameter that directly reflects the balance between neutron generation and consumption in every nuclear fission reactor. In this paper, by regarding the reactivity as an extended state-variable of point kinetics, a novel extended state-observer (ESO) is proposed. Theoretic analysis shows that this newly-built ESO provides globally asymptotically bounded estimation for the reactor neutron flux, concentrations of delayed neutron precursors and reactivity. Numerical simulation results illustrate the influence of the observer parameter to its performance, and show that this ESO can provide better reactivity estimation than the classical inverse point kinetics (IPK) method. The ESO has a simple form, and has only one parameter to be tuned online, which can induce an easy engineering implementation.