Surrogate-based engineering evaluation and service-life enhancement of a pleated 316 L metal-fiber cartridge for lead‑bismuth coolant purification

Corrosion-product control in lead‑bismuth eutectic (LBE) coolant loops is important for maintaining hydraulic reliability, reducing impurity accumulation, and extending the service life of purification components. However, engineering-scale data on the filtration efficiency, dust-holding capacity, and pressure-drop evolution of pleated metal-fiber cartridges for LBE systems remain limited. In this study, a pleated 316 L sintered metal-fiber cartridge was experimentally evaluated using a water-SiO 2 surrogate system, and the applicability of the surrogate was assessed through mechanism-based similarity analysis. The results show that both the surrogate and the target PbBi-Fe3O4 system operate in the creeping-flow regime (Re f < 1), with comparable Peclet numbers and interception-dominated capture, supporting the use of the surrogate for engineering performance evaluation within the investigated regime. Under representative operating conditions, the clean cartridge exhibited high instantaneous removal efficiency (>95%) and a dust-holding capacity of 1668 g/m 2 at a terminal pressure drop of 300 kPa. Continuous segmented regression revealed a two-stage pressure-drop/loading relationship with a transition at approximately 1027–1050 g/m 2 , corresponding to a shift from pleat-internal loading to outer-surface cake growth. This transition provides a practical maintenance indicator for cartridge replacement. Structural optimization showed that reducing the packing density of the sintered medium increased dust-holding capacity by 6.86%, while introducing an outer loose-fiber layer further delayed rapid pressure-drop growth. The best configuration, a 3 mm-compressed coating with an 8 μm fiber diameter, increased the corrected dust-holding capacity from 2048 to 3052 g/m 2 , corresponding to a 49.05% improvement. The present work establishes a surrogate-based engineering framework for evaluating and optimizing pleated metal-fiber cartridges for corrosion-product removal in LBE coolant purification systems.