This paper discusses virtual reality (VR) training for chemical operators on hazardous or costly operations of chemical plants. To this end, a prototypical training scenario is developed which will be deployed to industrial partners and evaluated regarding efficiency and effectiveness. In this paper, the current version of the prototype is presented, that allows life-sized trainings in a virtual simulation of a chemical reactor. Building up on this prototype scenario, means for measuring performance, providing feedback, and guiding users through VR-based trainings are explored and evaluated, targeting at an optimized transfer of knowledge from virtual to real world. This work is embedded in the Marie-Skłodowska-Curie Innovative Training Network CHARMING3, in which 15 PhD candidates from six European countries are cooperating.