Condensation heat transfer coefficient with noncondensible gases for heat transfer in thermal hydraulic codes

Condensation in the presence of noncondensible gases play an important role in the nuclear industry. The RELAP5/MOD3 thermal hydraulic code was used to study the ability of the code to predict this phenomenon. Two separate effects experiments were simulated using this code. These were the Massachusetts Institute of Technology's (MIT) Pressurizer Experiment, the MIT Single Tube Experiment. A new iterative approach to calculate the interface temperature and the degraded heat transfer coefficient was developed and implemented in the RELAP5/MOD3 thermal hydraulic code. This model employs the heat and mass transfer analogy since it considers the sensible and condensation heat transfer simultaneously. This model was found to perform much better than the reduction factor approach. The calculation using the new model was found to be in much better agreement with the experimental values. (author)