Numerical investigation of the thermal-hydraulics of the annular fuel assembly of a sodium-cooled fast reactor under rolling conditions

Le résumé fourni par la source

The annular fuel assembly represents an innovative fuel configuration designed to meet the requirements of Sodium-Cooled Fast Reactors (SFR). Annular fuel assemblies are one of the fuel configurations for pressurized water reactors that enhance the thermal-hydraulic performance of the reactor, thereby improving cooling efficiency. In addition, thus optimizing fuel utilization efficiency. The application of annular fuel is considered advantageous for SFR due to its numerous benefits in offshore nuclear power systems. The efficient cooling performance and compact design of SFR make them particularly suitable for deployment in ocean environments. During operation, the SFR will experience heave, such as heave, roll, and pitch induced by wind and wave actions. These fluctuations will result in periodic alterations to thermal parameters, including system fluxes and temperature differences, which will consequently impact the flow and heat transfer characteristics of the annular fuel assembly. Consequently, it is imperative to conduct comprehensive examinations of the performance of SFR under dynamic conditions in order to guarantee their reliable operation in complex ocean environments. The objective of this research is to investigate the heat transfer characteristics of the annular channel under rolling motion. The present research addresses the issue of heat transfer in the annular channel under rolling conditions. The results indicate that the rolling motion enhances the flow heat transfer in the system, and the average wall temperature and Nusselt number (Nu) undergoes periodic fluctuations. For a fixed period of rolling, the larger the rolling angle, the larger the amplitude of Nu oscillations in the sub-channels and the internal flow field. For a fixed angle of rolling, the larger the rolling period, the slower the flow rate and temperature changes in the sub-channels and the internal flow field, and the smaller the Nu oscillations. The impact of an elevated rolling angle on the Nu is more pronounced than that of the rolling period. However, both effects are constrained, and the amplitude of the Nu oscillation does not exceed 3.5751. This research contributes to the optimization of the design and operation strategy of the annular fuel assembly of SFR, ensuring its safety and high efficiency in ocean environments.

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