Development of a thermal–hydraulic system code with multi-dimensional modeling for liquid metal pool-type fast reactor and preliminary verification and validation

Abstract

Liquid-metal pool-type fast reactors exhibit unique transient and steady-state behaviors under operational and accidental conditions due to their complex three-dimensional geometries and flow transport properties. To accurately capture these properties, a system analysis code LIMSAC integrating three-dimensional complex spatial and sub-channel hydrodynamic components, is developed in this paper. The code employs the Jacobi-Free-Newton-Krylov (JFNK) method for solving the field equations and demonstrates excellent robustness in dealing with nonlinear and complex coupled phenomena in multi-physics field problems. The development of the code includes the construction of the governing equations and component models, the numerical discretization scheme and a detailed overview of the solution method. The code’s architecture and modules have been developed and validated through numerical tests and experimental data, showing the ability to accurately simulate the thermal–hydraulic characteristics of liquid metal reactor systems, including transient variations in natural circulation loops and thermal stratification in liquid metal pools. The validation results show that the code is capable of simulating the thermal–hydraulic characteristics of the liquid metal reactor system accurately, including the transient variations of the natural circulation loop and the thermal stratification phenomenon of the liquid metal pool. The simulation results are consistent with experimental data in general, demonstrating the accuracy and reliability of the code. Future work will focus on further analytical and experimental studies to develop multi-dimensional turbulence models, extend the code framework, and add component models to accommodate a wider range of engineering safety analysis needs.