Surface charge accumulation of particles containing radionuclides in open air

Abstract

Radioactivity can induce charge accumulation on radioactive particles. However, electrostatic interactions caused by radioactivity are typically neglected in transport modeling of radioactive plumes because it is assumed that ionizing radiation leads to charge neutralization. The assumption that electrostatic interactions caused by radioactivity are negligible is evaluated here by examining charge accumulation and neutralization on particles containing radionuclides in open air. A charge-balance model is employed to predict charge accumulation on radioactive particles. It is shown that particles containing short-lived radionuclides can be charged with multiple elementary charges through radioactive decay. The presence of radioactive particles can significantly modify the particle charge distribution in open air and yield an asymmetric bimodal charge distribution, suggesting that strong electrostatic particle interactions may occur during short- and long-range transport of radioactive particles. Possible effects of transported radioactive particles on electrical properties of the local atmosphere are reported. The study offers insight into transport characteristics of airborne radionuclides. Results are useful in atmospheric transport modeling of radioactive plumes.

A Test Chamber Investigation of the Effect of Charging on Aerosol Deposition on Indoor Surfaces

“…4 aerosols ranges from less than ten negative elementary charges to greater than one hundred positive charges (Gensdarmes et al, 2001;Kim et al, 2015). The amount of charge an aerosol can have depends on its particle size and surface area, with larger particles, having larger surface area, holding more charge than smaller particles (Wu et al, 2005).…”

“…The self-charging process makes radioactive aerosols unique as compared to ambient aerosols, where charge is generally assumed to be neutralized or very low (single elementary unit) due to aerosol interaction with the ions present in the air (Jayaratne et al, 2014) and charge on ambient indoor aerosols is found to be lower than charge on outdoor aerosols (J-Fatokun et al, 2008). In this study, through use of a corona charger, the aerosols were given a charge in a range representative of radioactive aerosols (Kim et al, 2015). This aerosol charge introduces an electrostatic interaction with other aerosols, and also with surfaces present in the surroundings (Filippov, 1992;Wistrom and Khachatourian, 2001).…”

Understanding Sorption Behavior and Properties of Radionuclides in the Environment

“…Two or more mechanisms may operate simultaneously [30]. It has been reported that electrostatic charge generated by radioactivity contributes significantly to surface interactions between particles and environmental surfaces [31]. In assessing the potential for interactions with complexing agents, uptake into the food chain and mobilization, paradoxically the same governing variables and processes affecting heavy metals and metalloids in the biosphere can be extrapolated to analogue radionuclides [32,33].…”

“…Charge of the radionuclides is the determining factor for exchange sorption. It has been shown that radioactive particles can be strongly charged and yield an asymmetric bimodal charge distribution [34,35]. Therefore the processes involving electrostatic interactions will play a role in predicting their transport.…”

“…The retardation factor, R and current decay coefficient, μ can be derived and is given by Eqs. (31) and (32), respectively [88,89]:…”