Calculation of Lead Shielding in Relative Distribution Measurement Systems of Neutron Flux in Reactors

The measurement system for relative distribution of multichannel neutron flux is designed to massively measure the radioactivity of irradiated foils.Every NaI detector measures one irradiated foil and the lead shield is used in detectors.To eliminate the effect of foils from other tracks on the measurement result of foil detector in its own track,this paper designs that the interference from the irradiated foils at the adjacent tracks on the measured tracks is less than 0.05%.This paper confirms the size of lead shield which meets the shield requirements by using the calculation method of point source integral and Monte Carlo verification method.