In contrast to large break, loss-of-coolant accident analysis, analysis of plant operational transients requires an accurate steady-state initialization and proper modeling of the actions of plant control systems during the transient. To assess the basic capability of the RETRAN-02 computer code to calculate operational transient phenomena, posttest analyses of the loss-of-fluid test anticipated transient tests L6-1, L6-2, L6-3, L6-5, and L9-1 were performed. The comparisons of the RETRAN-02 calculations with the experimental data show the importance of matching both the initial conditions and the boundary conditions. The results indicate that RETRAN-02 is capable of calculating operational transient phenomena with reasonable accuracy.