The goal of the PITSTOP (Immersive platform for structured operator training) project is to overcome the limits of traditional workplace training on dangerous systems and reduce the related risks, using an innovative integration of engineering simulation models and virtual reality (VR) tools. This article specifically presents the first VR platform for training on small-scale industrial steam generators, representative of a vast class of hazardous industrial equipment. The dynamic model of the steam generator was developed in matlab-simulink using a mixed physics-based and data-driven approach. The generator model includes the main engineering components, actuators and measuring equipment, as well as control logic and emergency procedures. It can simulate normal operations and emergency situations. The model was calibrated using experimental data collected from the real system at various operating conditions to align simulated performance with the real behavior. The VR environment was developed in Unity, a graphics engine widely adopted by the videogame industry, using three-dimensional computer-aided design models of the steam generator and its surroundings. The user can access this immersive system wearing an HTC Vive headset. Unlike most existing training systems, learners can interact with the actuators using bare hands gestures, without controllers, making the experience intuitive and easily accessible. By connecting the dynamic model with the VR environment, the user's interactions are directly provided to the steam generator model, which in turn directly outputs the steam generator response to the VR environment, providing audio and visual feedback to the user, as if they were actually acting on the real generator. The results from this study could boost the further development of training platforms to safely train operators and certify their competence.