This thesis addresses the problems encountered during the simulated validation of real-time reactive systems at the design phase before the implementation. We assume that such systems are modeled as timed labeled transition systems, following the TROM methodology with parameterized events. In the previous work on the simulation, the simulator's algorithm had problems simulating some real-time reactive systems, such as the Train-Gate-Controller and Robotics system. This thesis aims to correct the flaws related to time conflicts in previous models, separate the Data Model module from the Validation tool, and add support for parameterized events in the simulator. As a system grows larger, assessing the performance of mission-critical applications become more important. This thesis proposes an assessment of a system's performance in terms of functionality, based on a Simulation, and illustrates its approach using the Robotics case study.