To establish the sodium loop technology and investigate thermo-hydraulic behaviors of upper plenum of the FBR core through experiment, construction of a small scale sodium loop is necessary. In this study, the design and analysis of sodium loop piping were performed. The loop piping was analyzed according to RCC-MR code RC 3600 that is design and construction rule of fast breeder reactor. The integrity of the piping system under high thermal loads and design pressure was evaluated through analysis. The results of stress and fatigue analyses were within the allowable limit. Therefore the suggested piping design will preserve its integrity. An analysis procedure of the high temperature piping was established. (Author).