During 1980, RETRAN was used to simulate the reactor core response characteristics during the Peach Bottom 2 beginning of cycle 5 main steam relief valve (SRV) discharge tests. The SRV tests were conducted at power (50% power) for the purpose of demonstrating that the torus structural response with the “Tee” quencher design is less severe than the structural response predicted by the plant unique torus analysis. In comparison with the measured plant transient data, RETRAN predicted accurate reactor power and pressure trends and magnitudes during both the opening (depressurization) and closing (overpressurization) of the SRVs. Based on these results, it is evident that the RETRAN code and the RETRAN Peach Bottom plant model provide reasonable simulation of mild over/underpres-surization transient events. For the subject analysis, RETRAN 01 Mod 2 was implemented.