); [EMAIL_ADDRESS] (C.Y.) Xiaoming Yang  
1 CNNC Key Laboratory on Severe Accident in Nuclear Power Safety, China Nuclear Power Engineering Co., Ltd., No 117 Xianshuan North Road, Beijing 100084, China; [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.Y.) Xiaoming Yang  
1 CNNC Key Laboratory on Severe Accident in Nuclear Power Safety, China Nuclear Power Engineering Co., Ltd., No 117 Xianshuan North Road, Beijing 100084, China; [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.Y.) [PERSON]  
1 CNNC Key Laboratory on Severe Accident in Nuclear Power Safety, China Nuclear Power Engineering Co., Ltd., No 117 Xianshuan North Road, Beijing 100084, China; [EMAIL_ADDRESS] (H.L. ); [EMAIL_ADDRESS] (C.W. ); [EMAIL_ADDRESS] (C.  
The condensation process of steam mixed with noncondensable gas is very complicated, as it involves not only the exchange and transfer of mass, energy and momentum between steam and condensed liquid, but also the exchange and diffusion of energy and momentum between steam and noncondensable gas [1]. So far, the research on this process mainly consists of experimental studies [5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15] and theoretical analyses [16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28]. In the experimental aspect, researchers have paid much attention to the heat transfer characteristics of condensation under various working conditions [6; 7; 10; 14; 15], as well as heat transfer enhancement using variant means. They conducted many experiments and obtained different heat transfer correlations, like the commonly used Uchida [7], Tagami [8] and Dehbi [9] models and so on, and correlations were made with the heat transfer rate via gas concentration, pressure, temperature, surface subcooling, and some other parameters. However, the main obstacle is that most correlations are not universally valid, and each empirical relation has a very strict application condition. At the same time, a numerical calculation has become an important means to explain condensation phenomena by means of both lumped parameter codes and 3D CFD codes [20; 21]; in contrast to the experiments, the numerical method can obtain more detailed information about the flow characteristics and gas concentration distribution. And many factors have also been considered to affect the condensation efficiency [25; 26; 27; 28] like the geometrical parameter, thickness of film, suction factor and so on, but for pure theoretical numerical calculations, the calculation process is complicated and difficult to understand, and at the same time, too many iterations lead to a divergence of the calculation results. In a nuclear power plant, the condensation process of steam with noncondensable gas on the surface of a heat structure is accompanied by an intense heat and mass transfer, which directly affects the spatial distribution of the temperature and pressure in containment, and then affects the safe operation of the integrated reactor [4]. This paper analyzes and discusses this phenomenon, proposes a condensation calculation model, and applies this calculation model to the integral analysis code of the PISAA (Program Integrated for Severe Accident Analysis) for severe accidents. By conducting specific working conditions, the wall condensation model in the PISAA is compared and verified with the mainstream containment thermal hydraulic codes. Additionally, the calculation results of the model are validated by comparing the data with those of the Wisconsin condensation experiment [15]. Finally, a brief sensitivity analysis is performed on the condensation heat transfer model, which further improves the accuracy of the condensation heat transfer calculation.