A RETRAN-02 model has been developed for the Cofrentes nuclear power plant, a 2894-MW(thermal) Spanish boiling water reactor 6. The startup and pre-operational tests have been used to perform an extensive qualification of the model. Special attention has been given to the qualification of the control system models, and the emergency response information system station available at Cofrentes has proved to be a very powerful tool to record useful plant data. The tests used in the qualification include recirculation, pressure, and level control system tests, recirculation pump transfer to low speed, one feedwater pump trip, turbine trip, and main steam isolation valve closure. The very good results obtained with the model provide confidence in its future use in plant transient analysis. Several modifications have been made to the qualified model to prepare it for the analysis of abnormal transients. The modifications include improvements in the nodalization, simulation of the emergency core cooling system, and use of separate phase models. The models are at present being used for plant transient evaluation support, independent vendor licensing calculations, qualification of an improved operator training simulator, and studies of potential modifications to setpoints and systems operation for anticipated transient without scram mitigation.