Corrosion in liquid metal pump blades by molten salts

A catastrophic failure in a liquid metal pump within a molten salt reactor has revealed a pattern of accelerated corrosion on the impeller blades. High-temperature salts, combined with cyclic mechanical stresses, caused premature material degradation. This case exemplifies the challenges of fatigue in extreme environments, where the synergy between chemical attack and mechanical stress accelerates component lifespan.

CFD simulation and stress analysis to predict failures 🔬

To address this problem, a multidisciplinary workflow was employed. First, computational fluid dynamics (CFD) was modeled with Ansys CFX to simulate the liquid metal flow pattern and temperature distribution on the blade surface. The results revealed high-velocity and recirculation zones where salts concentrate. Subsequently, the thermal and pressure loads were imported into a finite element model in Siemens NX to calculate equivalent stresses. The superposition of these high-stress zones with areas of higher salt concentration identified the critical points for corrosion-fatigue initiation.

3D visualization and validation with real tests 🛠️

The three-dimensional reconstruction of wear using Volume Graphics allowed comparing the simulated erosion profile with the actual failed blade. The correlation was over 85%, validating the predictive model. This methodology demonstrates that integrating CFD and stress analysis not only explains the failure but also enables redesigning the blade geometry to reduce salt stagnation points, extending the component's service life under extreme operating conditions.

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