A RELAP5 model of a pressurized water reactor (PWR) power plant has been developed. The model of the power plant was a two-loop representation of a PWR power system with U-tube steam generators. A steady-state analysis of the model revealed that RELAP5 underpredicts the heat transfer from the primary to the secondary side of the reactor system. This is due to the fact that RELAP5 uses the heat transfer correlations that were originally developed to calculate the heat transfer coefficients for flow inside tubes, not the tube bundles. In order to mitigate the inaccuracy in the heat transfer predictions, several forms of nucleate boiling and critical heat transfer correlations were employed. As a result, a better heat transfer from the primary to the secondary was achieved. These modifications were also applied to obtain a 0.15-m (6-in.)-diam, cold-leg, small-break loss-of-coolant accident scenario. The response of the transient to these modifications was studied and is presented. The use of the modified correlations produces better steady-state results and predicts plausible transient behavior.