​Research reactors are a necessary basis for nuclear energy development and evolution. These reactors are those which paved the way to nuclear energy use, with the divergence of the first atomic pile CP-1 in 1942 at Chicago, and then, as early as the Liberation, the divergence of the French atomic pile ZOÉ in 1948 at Fort de Châtillon. For they so demonstrated the ability to generate and control nuclear chain reaction, which was then a major technological innovation, indeed. Since that time, they have kept on with their contribution, making it possible to measure neutron characteristics of reactors cores, investigate materials and fuels behaviour under irradiation, study the consequences of accident situations, validate new concepts as well as prototypes, and ensure teaching and operator training on actual nuclear facilities. In addition, research reactors are also implemented to meet research needs in Basic Physics to investigate  matter’s structure, as well as in various areas of industrial applications. Furthermore, they stand as an unrivalled tool to produce radionuclides for medical uses such as diagnosis and radiation therapy. This diversity of uses is echoed by a very wide variety of facilities, together with activities often performed within an international framework, and relating not only to reactor design and operation, but also to programs developed in these reactors.

Summary

• Foreword
  
• Research Reactors, their Use and History
  
• Validation Neutronics Calculations
  
• Testing Materials under Irradiation
  
• Investigating Accident Situations
  
• Worldwide Overview of Research Reactors
  
• Conclusion