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-generat...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.展开更多
This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the N...This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the NSC(Noyau de SCellement)experiment,designed to assess the performance of a sealing core composed of a mixture of 40%bentonite and 60%sand.The objective is to evaluate in situ hydraulic permeability,swelling behavior,and gas performance of the seal,which are essential components for the safe disposal of Intermediate-Level(IL)and High-Level Radioactive Waste(HLW)in deep geological repositories.The experimental setup,construction details of the NSC experiment,and the timeline of the project,from excavation,construction of the seal,and artificial hydration to hydraulic permeability tests,are comprehensively described.Andra has acquired valuable expertise in constructing an engineered barrier system,encompassing concrete plugs,and efficiently assembling a 5-m-long seal.Over the past decade,a controlled water injection process has been employed to hydrate the seal.The operational efficiency of sensors has been evaluated,with pore pressure sensors exhibiting moderate performance.In contrast,others,including total pressure,capacitive humidity,psychrometric humidity,and saturation sensors,demonstrate excellent performance up to their operational limits.The high-quality data obtained from this experiment will facilitate the modeling of the resaturation and hydraulic-gas performance of the seal.展开更多
基金financial support from the Nuclear Energy Science&Technology and Human Resource Development Project of the Japan Atomic Energy Agency/Collaborative Laboratories for Advanced Decommissioning Science(No.R04I034)The author Ruicong Xu appreciates the scholarship(financial support)from the China Scholarship Council(CSC,No.202106380073).
文摘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.
文摘This article presents findings from an extensive experimental program conducted by the French Agency for the Management of Radioactive Waste(ANDRA)at its Underground Research Laboratory.The focus of the study is the NSC(Noyau de SCellement)experiment,designed to assess the performance of a sealing core composed of a mixture of 40%bentonite and 60%sand.The objective is to evaluate in situ hydraulic permeability,swelling behavior,and gas performance of the seal,which are essential components for the safe disposal of Intermediate-Level(IL)and High-Level Radioactive Waste(HLW)in deep geological repositories.The experimental setup,construction details of the NSC experiment,and the timeline of the project,from excavation,construction of the seal,and artificial hydration to hydraulic permeability tests,are comprehensively described.Andra has acquired valuable expertise in constructing an engineered barrier system,encompassing concrete plugs,and efficiently assembling a 5-m-long seal.Over the past decade,a controlled water injection process has been employed to hydrate the seal.The operational efficiency of sensors has been evaluated,with pore pressure sensors exhibiting moderate performance.In contrast,others,including total pressure,capacitive humidity,psychrometric humidity,and saturation sensors,demonstrate excellent performance up to their operational limits.The high-quality data obtained from this experiment will facilitate the modeling of the resaturation and hydraulic-gas performance of the seal.
