Development of thermal hydraulic analysis code of annular fuel under flow blockage condition

Highlights: • A sub-channel code which is capable of modelling the flow blockage has been developed and verified. • The results of flow blockage of the inner channel and out channel has been obtained. • The effect of the flow blockage on the heat split and DNBR has been discussed. A sub-channel code capable of modelling the flow blockage of the annular fuel has been developed and verified by the experiment. A fuel conduction model has been developed for the blockage to consider the effect of the blockage on the temperature distribution of the fuel. Blockage at different position has been modeled and the middle blockage is selected as the calculation object. Blockage of inner and outer channel with different blockage rate has been calculated and the results of fuel temperature distribution, the heat split, the mass flow rate and the DNBR distribution has been obtained. Based on the analysis of the results, the blockage of inner and outer channel will have different effects on mass flow and heat split of the fuel, and the blockage of inner channel has a greater impact on DNBR and fuel temperature than that of outer channel.