Neutron activation analysis of aerosolized sodium chloride to simulate size-fractionation of plutonium in a glovebox

Abstract

Open front hoods are routinely used to mitigate a worker’s inhalation hazard. However, it has been shown that these hoods leak contaminates, especially when a worker is performing work in the hood. Quantitative measurement performed in the past does not reflect actually working conditions, but instead tends to conservatively bias the measurement by placing the sampler inside the hood or forcing the air-stream out of the hood toward the sampler. In order to accurately measure the amount of material routinely leaking from an open front hood, an air sampler was positioned in front of the hood opening and samples were taken while a routine sample digestion process was done. The digestion process involved the heating of a surrogate mixture to dryness. Samples were taken with and without a worker present during the digestion process. The samples were then analyzed at the University of Texas using neutron activation analysis. The detection level using this method was low enough to measure the amount of aerosol escaping the hood. Based on these measurements, the capture efficiency of open front hoods for PuO₂ is 84%.