Boron concentration present in spent fuel pools often has a significant impact on themeasurements of neutron based detection systems developed by the Next Generation SafeguardsInitiative (NGSI). As a result, a method of boron concentration determination is desired. Such ameasurement will help in the analysis of many of the detection systems. The approach used toquantify the boron concentration in this paper uses two neutron detectors; one is a bare ~3He tubeand the other is a cadmium (Cd) wrapped ~3He tube. The ratio of the two measured count rates isreferred to as a cadmium ratio and it scales with boron content in the water. Since the boron inthe water preferentially absorbs thermal neutrons, the bare detector response is perturbed relativeto the Cd lined detector because the Cd lined tube is essentially insensitive to thermal neutrons.The cadmium ratio was measured at boron concentrations ranging from 0 to 2400 parts permillion, by mass (ppm). In addition the experimental results were benchmarked with MonteCarlo N-Particle eXtended (MCNPX) simulations. Additional simulations were done todetermine the effectiveness of using results from existing detector designs from the NGSI effort.This work is supported by the Next Generation Safeguards Initiative, Office of NuclearSafeguards and Security, National Nuclear Security Administration
展开▼
