Study on properties of glass fiber filter material for positive zeta potential of coolant in nuclear power plant

The microscopic particles present in the primary coolant of a nuclear power plant, when activated, have radioactivity that can affect the safety of the plant’s operation and the radiation dose of the workers. Traditional filtration materials only use mechanical interception to achieve the removal of small particles, which causes the initial filtration resistance to increase continuously, reducing the service life of the filter material. The element leaching rate is also an important indicator of the performance of the filter material. Since the filter material itself leaches Si 4+ , it will combine with Ca 2+ , Mg 2+ , and Al 3+ ions in the coolant to form negative temperature coefficient silicates, which can form dense deposits at the hottest part of the fuel element bar, affecting the reactivity and fuel performance of the core. The leached SO 4 2− can cause intergranular corrosion on pipe materials, which has a significant impact on the service life of equipment. In this paper, nano-scale Al powder (50 nm) was used as raw material to successfully prepare AlOOH crystal by one-step hydrothermal method, which was grafted on the surface of glass fiber to prepare glass fiber filter material with high positive Zeta potential, and the method combining mechanical filtration and electrostatic adsorption was realized to remove small particles. At the same time, the leaching of Si 4+ and SO 4 2− was decreased. The experimental results showed that the filtration effect of the modified filter material for 0.45 μm particle size increased from 86.83 % to 99.95 %, and the 14-day Si 4+ leaching concentration decreased by 73.17 % and the 14-day SO 4 2− leaching concentration decreased by 84.43 %. This research helps advance the development of advanced materials that can withstand the harsh environment of nuclear energy systems, providing a reliable solution to ensure coolant purity and the safety of the entire reactor.