Fast reactor design and safety analysis methods (computer codes) have been under development for approximately sixty years. During the first forty years, code development was driven by the immediate needs of operational facilities such as Experimental Breeder Reactors I and II and the Fast Flux Test Facility. Development was further driven by programmatic needs to support advanced reactor programs such as the Clinch River Breeder Reactor Project and the Advanced Liquid Metal Reactor Program. By the early 1990s, design and safety analysis codes had been well established to addressed the unique characteristics of fast reactors.During the subsequent twenty years, however, development was nearly stagnant as a result of U.S. Government policy changes that abruptly canceled nearly all of the fast reactor research in the United States. As a result, the state of fast reactor design and safety analysis methods has deteriorated.This report defines a Fast Reactor Methods Development Plan that describes the scope of maintenance and development activities that are required to ensure the existing fast reactor design and safety analysis codes are available to adequately support a fast reactor authorization basis or license application. Of highest priority is the need to establish a software development team that will implement and execute quality software engineering practices to preserve the tremendous amount of knowledge and experience gained during the preceding six decades.Design and safety analysis codes for fast reactors provide unique capabilities not available in codes designed for light-water reactors. By 1980, the number of codes available for fast reactor design and safety analysis was around 130 in the U.S. alone. By 2010, the number had dwindled to approximately 60 worldwide, with less than eighteen potentially available in the U.S. Of these, seven are identified in this report as being critical for design and safety analysis: