Inhour equation and kinetic distortion in a two-point reactor kinetic model

A two-point reactor kinetic model for a strongly reflected reactor is developed and relevant parameters are assessed for the experimental zero-power reactor PROTEUS. The results are described in terms of an extended inhour equation and neutron source transfer functions for the core and the reflector. These transfer functions are applied to analyze reactor response to a pulsed neutron source which can be positioned in the core or in the reflector. The model gives a good description of the so-called kinetic distortion effect which complicates the reactivity determination by pulsed neutron source measurements. Quantitative results are in agreement with experimental data and with correction factors obtained with more detailed space dependent calculations. In order to deduce a correct reactivity value it is advised to apply a modified Simmons-King method with a two-point model version of the inhour equation.