ASME STP-NU-038

This report reviews the current experience on various high temperature reactor intermediate heat exchanger (IHX) concepts. There are several different IHX concepts that could be envisioned for HTR/VHTR applications in a range of temperatures from 850 to 950°C. The concepts that will be primarily discussed herein are:

• Tubular Helical Coil Heat Exchanger (THCHE)
• Plate-Stamped Heat Exchanger (PSHE)
• Plate-Fin Heat Exchanger (PFHE)
• Plate-Machined Heat Exchanger (PMHE)

The primary coolant of the NGNP is potentially subject to radioactive contamination by the core as well as contamination from the secondary loop fluid. Intermediate heat exchangers (IHXs) have been proposed as a means of separating the primary circuit of the NGNP or other process heat application from the remainder of the plant in order to isolate the radioactivity and minimize radiation doses to personnel as well as protect the primary circuit from contamination.