A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addition to valuable fuel cycle results. The systems section covers fuel pin and assembly design, fuel pin performance, overall systems considerations, and a major chapter on core materials-where advances in metal fuels and long-life structural capabilities are featured. The safety section includes both traditional safety analysis techniques as well as a perspective on methods to achieve passive safety response. Whereas the bulk of the book is focused on sodium-cooled fast spectrum systems, a final section features gas-cooled and lead-cooled fast reactor systems.