To address the inherent design contradiction among the three primary functions of a nuclear fuel assembly bottom nozzle—debris filtration

coolant flow capacity

and structural load-bearing—this paper proposes an integrated functional-structural design featuring a spatially curved filtration channel. Leveraging the integral forming advantages of additive manufacturing technology and employing the TRIZ methodology through technical contradiction analysis and inventive principles

the proposed design transforms conventional planar filtration into a spatially curved swept-rib structure

achieving functional integration of debris filtration and structural support. Based on this concept

five swept-function models—exponential

polynomial

Bezier

linear

and sinusoidal—were selected to construct representative structural units of the bottom nozzle. Comparative analyses were conducted on debris filtration efficiency

coolant flow performance

and structural strength. Numerical results indicate that the designed bottom nozzle exhibits excellent debris filtration performance

with a maximum filtration efficiency of 93.3%. Specifically

the Bezier and linear models achieve a filtration efficiency of 96.7% for elongated debris. Regarding coolant flow performance

the Bezier and sinusoidal models reduce pressure drop by approximately 29% compared to the polynomial model. Differences in structural strength among the five models are negligible

suggesting that the curved geometry has a limited impact on load-bearing capacity. Based on a comprehensive multi-performance evaluation

the Bezier curve swept model demonstrates the most balanced performance across debris filtration

coolant flow capacity

and structural strength

making it the optimal design. This study validates the feasibility of integrating additive manufacturing with innovative design methodologies for the development of key structural components in nuclear fuel assemblies and provides a reference for the design and engineering application of high-performance bottom nozzles.