Abstract: The filtration of coolant impurities in nuclear power plants constitutes a critical process for ensuring reactor system safety and prolonging equipment service life. However, current filter materials exhibit three fundamental limitations: supply chain vulnerabilities from import dependency (35% procurement cost escalation, 6~8 month maintenance cycles), excessive leaching rates of soluble silicon (21 mg/L) and sulfate ions (141 mg/L) in conventional glass fiber filters, and inadequate 0.45 μm particulate retention efficiency (baseline 86.83%). This study innovatively develops nano-aluminum modified glass fiber filters through one-step hydrothermal synthesis, achieving in-situ grafting of AlOOH nanolayers to construct functionalized filtration media with stabilized positive Zeta potential (+11 mV). Performance evaluations demonstrate: 99.95% retention efficiency for 0.45 μm particulates; 87.64% (2.6 mg/L) and 84.43% (22 mg/L) reductions in silicon/sulfate leaching compared to imported counterparts; and comparable contaminant-holding capacity (60.57±1.2 g/cm³). This technological breakthrough resolves the import substitution challenge for nuclear-grade filters, achieving two-order-of-magnitude enhancement in primary coolant purification efficiency and 40%~60% reduction in operator radiation exposure, thereby providing crucial technical support for safe and economical nuclear power plant operations.