Development of a thermal-hydraulic analysis code for annular fuel assemblies

In this work a detailed study of the annular fuel has been carried out. A thermal hydraulics code, ANUFAN (Annular Fuel Analysis), based on the bundle average method, capable of modeling both internally and externally cooled annular fuel pins is developed. Code predictions have been compared with calculations from Korea Atomic Energy Research Institute (KAERI) and MIT Heat transfer fraction difference between ANUFAN and RELAP was found about 1.7%. Analysis of a 54 - fuel rod assembly is carried out with 36 and 45 numbers of annular fuel pins keeping the same channel size and bundle power as of the solid fuel assembly. Fuel pin maximum temperature of the annular fuel is found much less than the solid fuel. MCHFR value for annular fuel is found much higher compared to that of the solid fuel of 54 - fuel rod assembly. The full paper covers the details of the computer code, the analysis carried out and the results obtained.