Improvement of Relap5/Mod3.2 Based on High-Pressure Horizontal-Stratified TPTF Experiment

The calculation of Relap5/Mod3.2 and Two Phase Test Facility（TPTF,Japan） experiment data is compared,which shows that Relap5 gives some derivation of void fraction distribution in the horizontal pipe.The analysis reveals that the horizontal junction flow regime of Relap5 has some error on the transition region and the transition equation of the horizontal-stratified flow regime,resulting in Relap5 mistaking some stratified condition as other condition.After modifying the transition region and the interphase drag equation on the transition region,new results from new Relap5 have been improved compared with the experiment data.