Speaker
Description
Tritium is a radioactive beta emission isotope of hydrogen with a mass of 3.0 and is mainly present as tritiated water(HTO) in wastewater discharged from nuclear facilities. However, since HTO and H2O have very similar physical and chemical properties, it is very difficult to separate a trace amount of HTO mixed in a large amount of water (H2O). There is a commercialized isotope exchange and hydrogen distillation technology that can remove tritium, but this technology is a process to remove HTO from pure water quality of D2O, so it is impossible to apply to large amounts of contaminated water such as contaminated water in Fukushima. The case of Fukushima in Japan may be considered a special case, but securing the technology to remove tritium generated by the operation of nuclear facilities is absolutely necessary worldwide, and since tritium can be used as fuel for nuclear fusion, securing the technology to separate and concentrate tritium is also necessary.
However, due to technical limitations in removing tritium from contaminated water at room temperature, it is currently difficult to achieve high tritium removal efficiencies with a single technology. Our research team has already developed four technologies capable of removing tritium from contaminated water at room temperature, but their low removal efficiencies have limited their application to large volumes of contaminated water.
In this study, to overcome these technical limitations, a method to improve efficiency and increase treatment capacity by fabricating the four technologies into standardized modules and arranging multiple modules in series or parallel was designed. A single standardized module was tested under various water quality and operating conditions to ensure reproducible data. This design allows for improved efficiency through serial arrangement of the module, and increased process capacity through parallel arrangement. To achieve this, single-module experiments will focus on ensuring reproducibility rather than improving tritium removal efficiency. Standardized modules based on diverse data enable mathematical modeling to simulate and predict removal efficiency when applying multiple modules, making them useful for designing large-scale tritium removal facilities. This research is currently developing standardized modules for four technologies (HTO selective adsorption material, zeolite membrane, electrochemical module, and PEM) their tritium removal performance has been confirmed through preliminary research. The experiment involves manufacturing a simulated contaminated water containing 40,000 Bq/L of tritium. The water is then passed through MF(Micro-Filtration), UF(Ultra-Filtration), and RO(Reverse Osmosis) systems to remove all contaminants except tritium, achieving a water quality of 1 μS/cm. The water is then passed through each module to remove tritium. Future research will explore the number and arrangement of modules for each technology (1×2, 2×1, 2×2, 4×4, etc.) and observe changes in removal efficiency by passing the same concentration of tritium-contaminated water through the process. Additional research will also be conducted to improve efficiency through a combined process that considers the characteristics and operating conditions of the four modules.