This article presents a collaborative system, called SCORE, useful for a multidisciplinary team designing a new nuclear power plant (NPP). It was developed during the first phase of the I 2 S-LWR project (Integral Inherently Safe Light Water Reactor). SCORE enables the generation of design cards (DCs). A DC includes four main spaces (Boy, 2005): (1) a rationalization space where the various components of the system being designed (SBD) are described in terms of design rationale, integration and requirements; this space includes declarative and procedural descriptions and statements; (2) an activity space where the current version of the SBD is displayed; it includes static and dynamic features; this space enables SBD manipulation; (3) a structure space where the various components and their interrelations are formally and declaratively described as systems of systems; (4) a function space where the various functions of the SBD are described in terms of procedural knowledge and dynamic processes involved; this space includes qualitative and quantitative physical and cognitive models. The rationalization space is informed using an adapted version of the QOC method (Questions, Options, Criteria), which was tested within the I 2 S-LWR design team. The activity space contains 3D models developed using AutoDesk Inventor, and transferred into the Unity game engine web player in order to facilitate integration within the DC spaces and enable intuitive manipulation of objects in the activity space. Two additional spaces were added: an instant messaging capability that allows design team members (DTMs) to exchange with one another on a DC; and a structured evaluation space. DCs are cooperatively created and refined by DTMs, and synthesized during periodic design meetings, the frequency of which may vary. Incrementally combining abstract explanations of designed elements and integration with their explicit visual representation improves mutual understanding among DTMs, and consolidates design decisions. This human-centered design (HCD) approach also improves individual and collective familiarization with the complexity of mixing several expert contributions in NPP design. In this case, HCD is not focused on end-users, but rather on the designers themselves.< Réduire