There is an ongoing effort to advance the nuclear energy systems in the US and around the world to meet the increasing demand for energy and enhance the safety and efficiency of nuclear power plants. This progress is facilitated by the increasing interest in the development of advanced reactor concepts that includes high temperature gases, supercritical fluids, liquid metals and molten salts. Each of these reactor technologies have different requirements based on the different fluids, temperatures, pressures, and flow rates needed for optimal operation, but they could all benefit from new heat exchangers with advanced design and configuration that optimize heat transfer at reduced cost.

Advancements in manufacturing processes and new innovative developments and designs have resulted in significant improvements in heat exchanger technology. Compact heat exchangers (CHXs) are developed for efficient transferring of heat from the primary to the secondary loop in nuclear reactors. They are characterized by low space and weight requirements, high thermal effectiveness, low-pressure drop, moderate to high design pressure capability, and high effectiveness approaching 95%. These attributes improve cost and efficiency of advanced reactors. Solid state diffusion bonding has been used to create CHXs for various applications. It is a solid state welding process, in which two contacting surfaces bond under high temperature and pressure in vacuum environment.

Since CHXs are expected to play a crucial role in the deployment of the next generation of nuclear reactors, materials should be suitable for withstanding the associated high temperature conditions. Alloy 800H is a nickel-iron-chromium alloys with good strength and excellent resistance to oxidation and carburization in high-temperature environments due to its high Ni and Cr concentrations as summarized. The alloy is certified in the ASME Sec. III Div. 5 Class A for high temperature applications up to 760ºC, which makes it suitable for immediate deployment in nuclear energy systems without further investigations.

This study focuses on the evaluation of microstructural and mechanical properties of diffusion bonded stainless steel 316L and 316H as well as Inconel 800H sheets. Results show high quality of stainless steel bonding with great mechanical properties. Ni was added to promote the bonding of 800H and various trials were performed to meet the mechanical properties of the base alloy.


Microstructural Characterizations of Diffusion Bonded of 316l, 316h, and 800h Alloys for Compact Heat Exchanger Applications

Division / Sponsors: 
Pressure Vessels & Piping (PVP)


Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2020/volume/83815

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