Creep-fatigue damage evaluation of sodium to air heat exchanger in sodium test loop facility

A high temperature design and evaluation of creep-fatigue damage for a sodium-to-air heat exchanger, AHX, has been conducted according to the recent versions of the high temperature design codes based on a full three-dimensional finite element analysis. AHX is a shell- and tube-type heat exchanger with 36 helical tubes, and has an outer diameter of 1.59 m and height of 6.5 m. AHX was installed in a sodium test loop facility, STELLA (Sodium integral effect test loop for safety simulation and assessment) recently constructed at the KAERI site. The materials of the shell and tube in AHX are 304SS and 316SS, respectively. Evaluations of creep-fatigue damage based on 3D finite element analyses were conducted at several critical locations of AHX according to the recent elevated temperature design codes of ASME-NH and RCC-MR, and the evaluation results of the two codes were compared. Based on the high temperature damage evaluation, the AHX design has been finalized, and fabrication of the component was conducted.