[en] This report describes the post Critical-Heat-Flux heat transfer experiments in a 3 x 3 rod bundle conducted at Lehigh University during the period of measurements of thermodynamic nonequilibrium in the post-CHF regime and to characterize its effects on the two-phase heat transfer. The data from these experiments are to be used for verification and improvement of post-CHF heat transfer models used in thermal-hydraulic codes. As part of this project a two-phase loop which incorporated special features and instrumentation necessary for post-CHF tests was constructed. The nine rod test bundle incorporated a heated shroud to simulate the operating characteristics of a large rod bundle. A special ''hot patch'' technique was developed and used successfully for the first time to achieve steady-state post-CHF conditions in a rod bundle. Special steam temperature probes, developed earlier at Lehigh for tests in single tubes, were modified for use in the rod bundle. Each test provided measurements of system of system pressure, coolant flow rate, wall heat flux, wall temperatures, two-phase equilibrium qualities, and vapor superheat temperatures. These primary data permitted determination of wall heat transfer coefficients, nonequilibrium vapor qualities, and when applicable, quench front propagation velocities. 35 refs., 68 figs., 16 tabs