AUTHOR=Wu Pan , Zhang Lixin , Shan Jianqiang , Zhang Bo 

TITLE=Researches on Special Thermal Hydraulic Phenomena of Annular Fuel Assembly by Sub-Channel Analysis Code-NACAF

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2021.696331

DOI=10.3389/fenrg.2021.696331

ISSN=2296-598X

ABSTRACT=Dual cooled annular fuel is a novel fuel design, which has the potential to improve the reactor power density while maintaining or improving the safety margin. The effects of tight-lattice, fuel burnup, fuel expansion, flow channel blockage on the thermal hydraulic performance of annular fuel is studied in this paper. A sub-channel analysis code named NACAF, is developed for annular fuel assembly or core analysis, taking into consideration of tight-lattice effects on prediction of pressure drop, critical heat flux and turbulent mixing, channel blockage model, heat conduction model for dual surface cooling condition, flow distribution between inner and outer channel. Validation work is carried out with comparing NACAF results with analytical solutions, as well as numerical results of existing sub-channel code for annular fuel, such as VIPRE-01 and TAFIX. Comparison results demonstrates NACAF’s prediction error is acceptable and it has the ability to simulate thermal hydraulic performance of annular fuels or annular fuel bundles. Based on the developed and verified NACAF, the special thermal hydraulic phenomena of annular fuel are studied to clarify the features of annular fuel.