Design space exploration for architecture selection: Radial Neutron Camera nuclear fusion diagnostic study case

System engineering is an established methodology meant to support engineering design activities for complex systems design. Nuclear fusion devices design complexity derives from contextual presence of both a challenging operating domain requiring frontier technology and a restrictive regulation on safety or systems compatibility aspects. System engineering methodologies adapted to nuclear design environment reduce risks of late design changes related to compatibility problems emerging at integration stage. Present work describes the methodology developed for the conceptual design phase of a nuclear fusion neutronic diagnostic, the Radial Neutron Camera for ITER plant. In particular the focus is on the characterization of design intents and the structured exploration of design domain aiming at baseline architecture to be engineered in next design phase. A formal definition of design domain space in terms of architectural elements has been developed to allow the instantiation of a set of candidate options. The instantiation process was structured according to sub-system intrinsic information content and potential mutual impact. Finally, architectural options have been assessed according to a specifically defined ranking function able to integrate information characterizing the candidate architectures deriving from different domains enabling a close collaboration with stakeholders.