ABSTRACT
This chapter presents the description of IHX, details of its thermal modeling, and various solution techniques for realistic assessment of steady and transient temperatures. The intermediate heat exchanger (IHX) transfers the heat from the radioactive primary sodium to the nonradioactive secondary sodium. The IHX and complete secondary sodium system serve as a physical barrier between the radioactive sodium and the tertiary steam/water system. The IHX in nearly all the reactors have had trouble-free operation except in the case of the PHENIX reactor. In this reactor in France, failure of a weld joint on the secondary outlet collector occurred due to differential expansion between the central downcomer tube and the outer shell. Thermal simulation of IHX can be by a lumped-parameter single-tube model or a detailed multi-channel model. The single-tube model can be further improved by considering several parallel channels and applying the appropriate flow maldistribution factors, to account for flow maldistribution during low-flow conditions.
