Development of improved spray system with effective electrical electrodes for aerosol removal: An experimental study in UTARTS facility

Safe reactor decommissioning, especially for damaged Fukushima Daiichi (1F) nuclear power plants, is vital for environmental safety. Key challenges include remotely cleaning radiation hotspots and cutting fuel debris within the damaged primary containment vessel. However, submicron radioactive Aerosol Particles (APs) can be generated, thus necessitating effective aerosol control and removal to avoid radioactive environmental pollution and reduce radiation exposure risks during 1F decommissioning. Flue gases containing submicron APs that result in environmental pollution can also generated from other industrial works, e.g., coal, mining and chemical sectors. Conventional water spray is difficult to scavenge these small APs. Although previous studies showed the effectiveness of charged droplets on accelerating aerosol removal, the charging configuration is also important to scavenging performance. Hence, this study performs aerosol scavenging experiments in our UTARTS facility with varying induction electrode designs. Experimental results show the saturation of scavenging efficiency at high voltage and indicate the importance of charging polarity. Moreover, proper configurations of electrode position, geometry and material are studied and discussed. Our findings can be beneficial for the improvement of spray system for aerosol removal to mitigate radioactivity release and minimize contaminated water production and have implications for gas purification in various environmental and chemical industries.