Advancing safety training for nuclear decommissioning and dismantling: Integrating MX-based approaches for improved competency development.

The decommissioning and dismantling (D&D) of nuclear power plants is a highly complex change process requiring significant technological, organizational, and human transformation. To navigate these changes effectively, managers and employees must be adequately prepared and supported. Despite the acknowledged need for training in this context, existing programs often lack a scientific foundation or a systematic evaluation. This study addresses this gap by developing and evaluating a scientifically grounded training program designed to support competency development of managers and employees in occupational safety during D&D. The training was derived from a comprehensive training needs assessment, including analysis of safety events and interviews with subject matter experts, and implemented as a problem-based training approach enriched with Mixed Reality (MX) elements. A multi-phase evaluation was conducted with two pilot groups (N = 15) from Germany and Switzerland. Results showed consistently positive reactions to the training design, relevance, and usability of the MX environment, alongside low simulator sickness scores. However, objective knowledge gains were inconsistent, with a temporary decline immediately after training, while follow-up results indicated stabilization. Findings suggest that MX-based training is well accepted by participants and offers promising potential for safety training in D&D and other high-risk socio-technical systems, while highlighting the need for further research on its effects on objective performance and long-term learning outcomes.