The purpose of this report is to document elevated temperature design knowledge and experience accumulated over the past two decades by engineers in France, Germany, Japan, the United Kingdom (U.K.), and the United States (U.S.).The recommendations, guidance and proposed use of structural design methods presented here are based upon the development programs pursued by these five countries.Although there are some differences in research priorities, overall similarities among national development programs confirm a common perspective in problem identification and the problem resolutions have created an international consensus on LMFBR structural design technology development needs and future technology directions.