Improvement of the condensation heat transfer model of the MARS-KS1.3 code using a modified diffusion layer model

摘要

The thermal-hydraulic system code, MARS-KS1.3, tends to underestimate the condensation heat transfer under the presence of non-condensable gases. To improve its condensation heat transfer model, we adopted the Herranz's diffusion layer model and further developed it, mainly focusing on thermal-hydraulic conditions in a nuclear containment during a hypothetical accident. Two key modifications include (i) the correlations to calculate heat and mass transfer on a vertical external surface for various flow conditions are adopted and (ii) a turbulent diffusion coefficient is applied to consider the effect of turbulence on mass diffusion.