Evaluation of B10Plus+* Proportional Detectors for Neutron Coincidence Counting

GE-Reuter-Stokes (GERS) has developed a new line of neutron proportional counters, the BRIPlus+w proportional counter. The detector design is intended to serve as a costeffective alternative to traditional He-3 proportional counters in a variety of applications. The detector is a hybrid design B-10-lined tube optimized with the addition of a small quantity of He-3 gas to improve the detector performance and efficiency. As a demonstration of the BIOPlus+* detector, GERS has constructed a Uranium Neutron Collar (UNCL) system consisting of B10Plus+ proportional counters. GERS has designed and built a demonstration UNCL system intended to match the performance of a Type-I UNCL design in Pressurized Water Reactor (PWR) geometry operating in thermal mode. GERS offered their system on loan to the International Atomic Energy Agency (IAEA) Safeguards Division of Technical and Scientific Services for an assessment of the detector technology and the demonstration system. We have characterized the demonstration UNCL system and compared its performance with a traditional Type-I UNCL design in regular use by the IAEA. This paper summarizes our findings and observations during the characterization and testing activity.