The Thermal-Hydraulic Analysis and Optimization of Annular Fuel for Lead-Cooled Fast Reactor

The annular fuel element is a safe and efficient new fuel element type. According to previous studies on PWRs, it can bear higher core power density while maintaining or even improving reactor safety when compared to traditional rod lattice fuel rods. In this paper, the application of annular fuel element in lead-cooled fast reactor is studied. Firstly, the flow and heat transfer characteristics of lead-bismuth in annular channel are analyzed by using the computational fluid dynamic method. On this basis, a thermal hydraulic calculation code suitable for annular fuel in lead cooled fast reactor has been developed, which is verified by comparing with CFD results. The application and design optimization of annular fuel in the lead-cooled fast reactor core are carried out using the developed annular fuel single channel code. The effects of different annular fuel parameters on the results are studied, and the core design with rod lattice and annular fuel element is compared and analyzed. The calculation results show that with the same fuel volume and coolant mass flow rate, the maximum core temperature of the annular fuel element is about 600K less than that of the rod bundle fuel element, which shows that the annular fuel element has significant safety superiority.