This paper reports on the current version of the RELAP5/MOD2 computer code which underpredicts the degree of superheat in the secondary side of the steam generator bundles. Many studies have concluded that this is due to overprediction of the interphase drag force. New interphase drag correlations have been developed for the bubbly and slug regimes. These correlations were implemented in the current version of the RELAP5/MOD2 computer code. Steady-state conditions for 65, 75, and 100% power loads of 30-tube once-through steam generator tests are simulated. The calculated primary- and secondary-side temperature profiles show that the new interphase drag correlations achieve closer agreement with experimental data than the temperature profiles of the original code.