To study the feasibility of the Test Blanket Modules (TBM) replacement operations in ITER Port Cells, CEA develops a mixed (digital & physical) validation by simulations approach with immersive technology to verify hands-on operations. Main validation criteria concern operator accessibility, posture, detailed procedure sequence and time spent at workstations. Such complex replacement operations will assume series of hands on tasks for both normal and abnormal situations, sometimes with protection such as Air-Fed Suit (AFS). After initial validation of key operation feasibility on digital mock-up, the goal is to optimize the process with minimization of occupational radiation exposure under the As Low As Reasonably Achievable (ALARA) requirement. Virtual reality tools provide relevant means to develop a credible replacement scenario in a context of complex configurations. The process includes features such as ergonomics assessment tool coupled to multi operators’ collaboration, tangible tools and integration of advanced real time physics engine. Lessons learnt from the field of existing CEA facilities enable identifying key parameters related to workstation Humans factors. This first set of observations would help to define methodology and criteria for qualification of operation in AFS. The Digital simulation validation is deployed with a nuclear operator avatar in AFS to demonstrate Nuclear Maintenance Operation feasibility considering study of arduousness, accessibility and visibility thanks to real time motion capture. The recording of the whole simulation allows tracing and replaying for post-analysis data including body angulations, clash detection and operator field of view. The integration of this approach at an early phase of the design process enables validating technical options for replacement scenario. This leads to promising and beneficial results concerning design and integration of complex components in constraint working environments. This paper presents a review of the CEA studies regarding the extended virtual reality capabilities and results to support design TBM integration and replacement scenario within a nuclear environment framework.