High-Temperature Design of 700°C Heat Exchanger in a Large Scale High-Temperature Thermal Energy Storage Performance Test Facility

High-temperature design evaluations of 700°C (1292°F) heat exchanger was conducted that would be installed in a large-scale high-temperature thermal energy storage performance test facility under development at KAERI site. The helical tube type sodium-to-air heat exchanger, AHX with 125kWt capacity of Type 316L austenitic stainless steel would be subjected to high-temperature operation at 700°C. Case studies in elevated temperature designs were conducted for the two materials of Type 316L and Type 316L(N) stainless steel codified in French high-temperature design rules of RCC-MRx. Because some significant material properties are not available up to 700°C in RCC-MRx, the lack material properties and design coefficients were determined through high-temperature material tests and relevant determination procedures. Another case studies on design temperatures with 700°C and 650°C (1202°F) in sodium coolant were conducted due to the availability of material properties in the design rules, and comparisons were made among the four cases of the two materials (316L and 316L(N)) and two design temperatures (700°C and 650°C).