Validation of the MSG (Multi-dimensional Thermal-hydraulics Analysis Code for Steam Generators) for CFD Modelling of Sodium Heated Steam Generators

Abstract

A CFD code, MSG (Multi-dimensional Thermal-hydraulics Analysis code for Steam Generators), which is optimized for the helical coil type steam generators of the MONJU Fast Breeder Reactor at Tsuruga, Japan, has been developed. The purpose of this study is to validate the MSG code against experimental data recorded at MONJU and at the 50 MW steam generator test facility (SGTF) at O-arai Engineering Center, Japan, and to perform a cross-correlation with results from the superCOPD code. Quantitative all benchmarks produced sodium temperatures within 2% of measured values, whereas steam temperatures were scattered within 5%. Qualitative, discrepancies between the calculational mesh and the actual physical model of the facilities resulted in higher deviations in a fine mesh than in a crude and in the MONJU benchmarks notable surges were observed in the outlet steam and sodium temperatures. The SGTF in-vessel sodium temperature distributions revealed an overestimated rate of heat transfer. Finally, in the superCOPD code the analysis revealed a fixation of the calculated steam outlet temperatures caused by an inadequate treatment of steam superheat. It was recommended that the numerical scheme of the MSG code should be optimized and that the heat transfer correlations should be improved.