Assessment and improvement of condensation models in RELAP5/MOD3.2

The condensation models of the standard RELAP5/MOD3.2 code are assessed and improved based on a database that is constructed from previous experimental data of various condensation conditions. The RELAP5/MOD3.2 default model of laminar film condensation does not give any reliable predictions, and the alternative model always predicts values higher than those of the experimental data. Therefore, a new correlation based on the experimental data of various operating ranges is needed. The Shah correlation, which is used to calculate the turbulent film condensation heat transfer coefficients in the standard RELAP5/MOD3.2, gives good agreement with the database except for Kuhn's experimental data. The RELAP5/MOD3.2 horizontally stratified condensation model overpredicts both cocurrent and countercurrent experimental data. The Kim correlation predicts the database relatively well compared with that of RELAP5/MOD3.2.