IFMIF (International Fusion Materials Irradiation Facility) will be an accelerator-based neutron source to test fusion candidate materials. The Engineering Validation and Engineering Design Activities (EVEDA) of IFMIF are aimed to deliver the complete engineering design file of this major facility. Achieving a high level of availability and reliability is a key point for IFMIF mission. A goal of 70% of operational availability has been established. In order to fulfil the availability requirements, RAM (Reliability, Availability and Maintainability) has to be considered during the engineering design phase. This paper summarizes the methodology developed and the proposed process aimed at including RAM in the design of IFMIF, as well as the activities performed in this framework. Overall RAM specifications have been defined for IFMIF project. RAM methodology dealing with RAM design guidelines, reliability database and RAM modelization has been developed. As a first step for the iterative process of RAM analysis of IFMIF design, a fault tree model based on a new reliability database has been performed with Risk Spectrum®. The result is a first assessment of the availability and first allocation of RAM requirements.