Passive Electrostatic Precipitator Device for Radionuclide Monitor Systems

Currently, the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty Organization relies on a network of stationary air samplers for collecting and analyzing radionuclide specimens. Recognizing the necessity for developing the next generation of portable radionuclide analyzers, the filtration unit emerged as a critical component for enhancement. Among various filter methods, electrostatic precipitators (ESPs) were identified as a promising technology due to their demonstrated increased collection efficiency compared to filter media at particulate matter (PM) sizes <500nm, along with significantly reduced pressure drop. To fulfill the DoE Office of Nuclear Detonation Detection's (NDD) objective of developing ESP systems for local-distance (<200 km) radionuclide monitoring, GVD successfully proposed a passive electret-based ESP (EESP) filter system employing initiated chemical vapor deposition (iCVD) polytetrafluoroethylene (PTFE) electret coatings. This approach yielded collection efficiencies of >80% for PM of 200nm with negligible pressure drops across the filter. In Phase II, GVD will focus on enhancing electret charge storage by optimizing iCVD PTFE deposition conditions, thickness, and substrate materials, as well as exploring the effects of pulsed corona discharge. Additionally, the resilience of materials to extreme environmental conditions will be evaluated to ensure long-term stability for storage and field-use. To ensure precise testing, GVD will collaborate with Lab Machinist Solutions (LMS ľ mechanical design consultant) to design high-precision test cells, enabling controlled geometric parameters and flow conditions during PM efficiency testing. These test cells will be utilized at the Aerosol Research and Engineering Labs (AREL) facility, employing a custom-built aerosol dispersion and measurement test rig. Each cell will undergo aerosol flow testing to determine how variations in electret materials, test cell geometry, and induced dynamic flow conditions affect collection efficiency. Based on these findings, GVD will select the most promising conditions for implementation in prototype demonstrations. To aid in prototype design, GVD will closely collaborate with LMS and XIA (experts in radiation detection/analysis) to integrate the EESP into a system capable of demonstrating critical interactions found within a portable radionuclide monitoring system, such as reel-to-reel implementation and media-detector interfacing. Furthermore, GVD will initiate scale-up processes within the Phase II period by defining designs for the coating reactor and corona charger to facilitate post-Phase II scaling to commercial batch sizes. This in tandem with collaboration from Mann+Hummel (internation filter manufacturer) will propel GVDĺs innovation to commercial success.