Technical Basis for Proposed ASME Code Case for Construction of Compact Heat Exchangers in High Temperature Reactors

The U.S. Department of Energy has recently completed a research program to support the development of the compact heat exchanger (CHX) for use in high temperature advanced reactors. The project was executed by an Integrated Research Project (IRP) and includes team members from the University of Wisconsin–Madison, University of Michigan, Georgia Institute of Technology, University of Idaho, North Carolina State University, Oregon State University, Electric Power Research Institute, MPR Associates, and heat exchanger manufacturers CompRex and Vacuum Process Engineering. The research was guided by a roadmap to support the eventual adoption of an American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section III, Code Case for compact heat exchanger designs in high temperature reactor service. This roadmap is outlined in Journal of Nuclear Engineering and Radiation Science, NERS 19-1161, which identified specific research gaps to support the Code Case. The IRP has completed the research and the ASME Section III Standards Committee is in the process of writing and approving a Code Case for Section III, Division 5, Class A applications. This paper provides the detailed technical basis for the ASME Code Case for CHX. The paper provides a vital link between the research results and the proposed Code Case and closes the research gaps that are tied to the original Roadmap. In addition, the paper provides further detailed commentary on the proposed requirements. The major technology gaps included material properties, failure modes and effects, analysis methods, and examination methods. The IRP studied basic material properties of diffusion bonded plate, creep and fatigue models, development of NDE methodology and development of advanced analytical approaches to design.