Development of neutron flux measurement by using prompt and delayed self powered neutron detectors

Abstract

As an effort to improve operating margin, an accurate measurement of neutron flux with delayed and prompt self powered neutron detectors has been studied in this paper. Cobalt and Rhodium has been used as emitters of prompt and delayed detectors, respectively. For sensitivity calculation, we perform Monte Carlo simulation by considering such aspects as, neutron capture rate, insulator effect, neutron self shielding factor of the emitter, electron escape probability and emitter burnup. Sensitivities from our Monte Carlo simulation show good agreement with those measured or calculated by others. It is found that a step change of neutron flux, ramp increase of neutron flux and a sinusoidal neutron flux after a long steady state reactor operation are to be measured accurately by the combination of delayed and prompt self powered neutron detectors.