High temperature design of finned-tube sodium-to-air heat exchanger in a sodium test loop

•High temperature design of finned-tube heat exchanger (FHX) in SFR were conducted.•Full 3D FE analyses for the sodium-to-air heat exchanger unit were performed.•Stress levels of the FHX unit based on full 3D analyses were not severe.•Creep–fatigue damage as per design rules was evaluated to be within allowable limit. A sodium test loop called ‘SELFA’ (sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger) for simulating thermal hydraulic behavior of the FHX (finned-tube sodium-to-air heat exchanger) unit in a Korean prototype sodium-cooled fast reactor is planned to be constructed at KAERI (Korea Atomic Energy Research Institute). In this study, the elevated temperature design for a model FHX and creep–fatigue damage evaluation have been conducted for the model according to the design codes of ASME section III subsection NH and RCC-MRx based on full 3D finite element analyses. Design optimization for the finned-tubes and tube arrangements in the scaled-down FHX has been performed. The materials of the FHX and piping systems are austenitic stainless steel type 316. The design temperature of the SELFA test loop is 600°C and the design pressure is 1MPa. The damage evaluation results have shown that no creep–fatigue damage occurs in the present design of the FHX under the intended test conditions.