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A Preliminary Study for CRUD Removal by Multiple Membrane of Electro-Kinetic Process
Sion Kim,Byung Seon Choi,Sang Yoon Park,Bum Kyoung Seo,Won Geun Son,Changhyun Roh 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2
When decommissioning of nuclear facilities happens, large amounts of radioactive wastes are released. Because costs of nuclear decommissioning are enormous, effective and economical decontamination technologies are needed to remove radioactive wastes. During NPP operation, corrosion product called Chalk River Unidentified Deposits (CRUD) is generated. CRUD is an accumulation of substances and corrosion products consisting of dissolved ions or solid particles such as Ni, Fe, and Co on the surface of the NPP fuel rod coating. CRUD is slowly eroded by the circulation of hot pressurized water and later deposits on the fuel rod cladding or external housing, thereby reducing heat production by the nuclear fuel. Decontamination of radiologically contaminated metals must be performed before disposal, and several methods for decontaminating CRUD are being studied in many countries. Decontamination technology is an alternative to reducing human body covering and reducing radioactive waste disposal costs, and much research and development has been conducted to date. Currently, the importance of decontamination is emerging as the amount of waste stored in radioactive waste storage is close to saturation, and the amount of radioactive waste generated must be minimized through active decontamination. In this study, a preliminary study was conducted on the removal of CRUD by multiple membrane in an electro-kinetic process using an electrochemicalbased decontamination method. Preliminary research to develop a technology to electrochemically remove CRUD by using a self-produced electrochemical cell to check the pH change over time of the CRUD cell according to voltage, electrolyte, membrane and pH change.
김시온 ( Kim Sion ),조은하 ( Jo Eunha ),최수훈 ( Choi Soohoon ) 한국물환경학회 2020 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2020 No.-
In the current research, various conditions were evaluated to understand the release of fibrous microplastics and organic leachate from teabags. Six commercial teabags composed of 4 different plastic materials were tested under different temperatures, fiber damages, and water contact times. The main object of the research was to verify the amount of microplastics or organic leachate that may occur in tea consumed in our every day lives. The main focus was to verify the fibrous microplastic release and organic leachate of teabags under different damages. Damages of 1 ~ 10 cm were conducted on the teabags and submerged in glass vials under different temperatures. The teabags were cut with steal scissors of different degrees and the tea leaves were removed. Empty teabags were washed with deionized (DI) water for three trials before the experiments were conducted. Three empty teabags were submerged in every glass vial and submerged under constant temperatures in a water bath. the water bath contained a shaker where the samples were shaked during each trial. After being submerged in the water bath, the water from the teabags were filtered through a cellulous acetate membrane filter with pore sizes of 1 μm. Each filter was rinsed thoroughly and filtered with DI water before filtrations of the teabag samples. Filtered fibrous microplastics were counted with an optical microscope. Residual microplastics in the filtered water were analyzed with a TOC anayzer, dynamic light scattering analyzer, and SEM imaging. Results showed a logametric increase for both fibrous microplastic release and organic leachate with the increase of the damage inflicted on the teabags. Samples under higher temperatures also showed a higher release of the fibrous microplastics and leached TOC matter. The time for which the damaged teabags were submerged under water also showed a strong correlation with plastic release and TOC leaching. The hydraulic size of the filtered microplastics were in the size range of 1 nm to 2.4 μm. SEM resulted also showed similar sizes of microplastics with EDX results indicating the fibers as polymeric matters. The type of teabags and its assembly method also indicated a degree of influence in the release and leachate of the teabags. The current research has showed the amount of potential mircroplastic consumption via tea consumption.