Abstract: The primary heat exchanger is a key heat transfer component for lead-based reactors, which directly affects the economy and security of the reactor. Here, based on the model of heat exchanger of a lead-based natural circulation reactor, the influences of the tube length, outer diameter, wall thickness and tube pitch on the thermal-hydraulic analyses were discussed. JF factor was used to evaluate the comprehensive performance of the heat exchanger, on the basis of which, the best structure parameter A1B2C1D2 was determined by using CR and SN factor. The results show that tube length makes a greatest contribution to comprehensive performance, and the influence of tube pitch is almost negligible.

Key words: lead-based reactor, primary heat exchanger, thermal-hydraulic analysis, JF factor