Determination of small reactivity in real time by the inverse kinetics method

Abstract

This article describes measurements of small reactivity which have been carried out on-line and in real time. Calculations were made with use of a one-point approximation and the inverse kinetics method. Experiments were performed on the fast-thermal critical assembly at the Institute of Nuclear Research in Świerk. Having in mind the significance of precision in reactivity measurements applied to reactor diagnostics, the authors tested the accuracy of the inverse kinetics method algorithm. The measurements carried out in real time on a reactivity meter designed on the basis of this method are influenced by an error of ≲ ± 0.06¢, and the measurements of the steady reactivity executed during 80 sec after perturbation are determined with an error of ∼ ± 0.012¢.