Experience has shown that an integrated decision making process, including deterministic and probabilistic analyses together with good engineering practices, consideration of operating experience and sound managerial arrangements, is effective in refining and improving safe design and safe operation of nuclear installations. This publication is intended to promote a common understanding among the international nuclear community of how the concept of risk can be used in making safety decisions relating to nuclear installations. It identifies the framework, principles and key elements for integrated risk informed decision making (IRIDM) and describes the interrelationship between the key elements as well as the integration of their input. Although this publication is focused on the use of IRIDM in the context of nuclear power plants, including their fuel handling and storage systems, it can be equally applied with appropriate adjustments to other nuclear facilities and activities as well as to non-nuclear applications.