Assessment and Improvement of the Horizontal In-Tube Condensation Heat Transfer Model in the MARS code

Extensive researches have been carried out for enhancing the safety of nuclear power plants and, especially, the development of passive cooling systems, such as passive containment cooling system (PCCS) and passive residual heat removal system, is increasingly important, where condensation is a crucial heat transfer mechanism. Recently, Ahn & Yun et al. developed a horizontal in-tube condensation heat transfer model as one of the activities for the PCCS development. In this work, we implemented the Ahn & Yun's condensation heat transfer model into the MARS code and assessed it using the PASCAL experimental data. Based on the results of the assessment, we identified the limitations of the Ahn & Yun's model and suggested a modified Ahn & Yun's model, and assessed the model using various experimental data.