Development and Verification of Thermal-Hydraulic Constitutive Model for Rectangular Channel

The plate-shaped fuel element has good heat transfer characteristics, high average power density of the core, and low temperature of the fuel core, which is beneficial to improve the power-to-volume ratio of the core and ensure the safety of the core. Therefore, plate fuels are widely used in compact reactors such as research reactors, integrated reactors, and high-flux reactors. at present, most thermal-hydraulic analysis programs, such as RELAP, RETRAN, THEATRE, are mostly developed for large-scale pressurized water reactors using rod-shaped fuels. It is suitable for narrow rectangular channel of plate type fuel core. Based on this, this paper developed a set of thermal-hydraulic constitutive relation models suitable for narrow rectangular channels, including: flow resistance coefficient calculation model, wall heat transfer Coefficient calculation model, CHF calculation model, etc. The thermal-hydraulic constitutive relational model library of rectangular channel of plate-shaped fuel element is developed by using C++ language. In this paper, the developed constitutive relation model is transplanted into the reactor thermal-hydraulic real-time simulation program, and the IAEA 10MW material test reactor (MTR) benchmark is used to verify the developed rectangular channel thermal-hydraulic constitutive relation model library. Simulation analysis is carried out for two typical accident conditions, reactive introduction (RIA) and loss of flow accident (LOFA) defined in the benchmark problem. correctness.