Efficient control and removal of laser-generated aerosol particles by combining water spray with pre-injection of electrical charged mist for nuclear reactor decommissioning

Abstract Laser-induced aerosols, predominantly submicron in size, pose significant environmental and health risks during the decommissioning of nuclear reactors. This study experimentally investigated the removal of laser-generated aerosol particles using a water spray system integrated with an innovative system for pre-injecting electrically charged mist in our facility. To simulate aerosol generation in reactor decommissioning, a high-power laser was used to irradiate various materials (including stainless steel, carbon steel, and concrete), generating aerosol particles that were agglomerated with injected water mist and subsequently scavenged by water spray. Experimental results demonstrate enhanced aerosol removal via aerosol-mist agglomeration, with charged mist significantly improving particle capture by increasing wettability and size. The average improvements for the stainless steel, carbon steel, and concrete were 40%, 44%, and 21%, respectively. The results of experiments using charged mist with different polarities (both positive and negative) and different surface coatings reveal that the dominant polarity of aerosols varies with the irradiated materials, influenced by their crystal structure and electron emission properties. Notably, surface coatings such as ZrO 2 and CeO 2 were found to possibly alter aerosol charging characteristics, thereby affecting aerosol removal efficiency with charged mist configurations. The innovative aerosol-mist agglomeration approach shows promise in mitigating radiation exposure, ensuring environmental safety, and reducing contaminated water during reactor dismantling. This study contributes critical knowledge for the development of advanced aerosol management strategies for nuclear reactor decommissioning. The understanding obtained in this work is also expected to be useful for various environmental and chemical engineering applications such as gas decontamination, air purification, and pollution control.