A research reactor is an extraordinary tool that can contribute to a country’s scientific resources, improve health care, and help to increase industrial and agricultural productivity, if it is appropriately conceived, managed and supported. This requires a strong policy and technical infrastructure, and management of long term financial liabilities. This publication sets out the four phases of a research reactor project with their associated milestones, starting with a careful assessment of the need for the research reactor, the issues it raises and the measures to address them. The publication provides a framework for self-assessment of readiness for a research reactor project and the resource requirements that it will impose. The guidance provided in this publication will be helpful for decision makers from governments, operating organizations and regulatory bodies as well as project sponsors and planners.