Performance of different duct-nozzle arrangement on heat removal from a nuclear fuel storage vault under regular operating conditions

Abstract

The work presents a numerical analysis of airflow and heat transfer in a nuclear fuel storage vault for a fast breeder reactor. Suitable modifications in the inter-connecting duct geometry and overall ventilation design were suggested to obtain an efficient ventilation arrangement. After proper validation, the effect of variation in shapes of inter-connecting ducts on effective heat removal and optimization of air exchange rate through the vault was considered for investigation. Furthermore, the study presented the variation of airflow and temperature distributions inside the domain of the vault for various ducts and nozzles combinations. The results showed that the overall ventilation performance of the nuclear fuel storage vault was enhanced when square duct-nozzle combinations were put to application. It was also found that for all nozzle-duct arrangements, the introduction of diffusers on the nozzle-tip enhanced the mixing of air, which resulted in an improvement of heat removal from the subassemblies. The ducts connecting the blanket and the fuel enclosures were rearranged and the influence of interacting air jets on heat removal was studied and discussed. Also, parallel and cross arrangements of nozzle-mounted inter-connecting ducts were compared for efficient heat removal. The simulated results will be helpful in designing a suitable ventilation system and regulating the airflow distribution.