Severe accidents in Sodium Fast Reactors: Safety Study Approach, Prevention and Mitigation by Design is a unique presentation of research work from the Sodium Fast Reactor Severe Accident team at CEA. Focusing on in-core and out-core severe accident phenomena, this book analyzes severe accident scenarios and mitigation, related calculations and tools, and key outcomes from important experimental programs. The book describes the state-of-the-art on severe accident research which will help to inform and direct further pre-conceptual Generation IV SFRs. Lessons learned from the pre-conceptual phase of the French ASTRID project are highlighted alongside different approaches to demonstrate robustness. To support the demonstration of concepts explored, a special section dedicated to calculation tools and their validation offers readers a unique set of tools to guide and inform their own research work. Readers will gain a deep understanding of methodologies to illustrate approaches as well as an overview of safety approaches from key countries based on the editor’s rich international collaboration.