A Fan Controlled Sodium to Air Heat Exchanger Design for Fail Safe Decay Heat Removal in Sfr

Passive safety systems help to improve overall plant safety, reliability and resilience. In this article, we propose a fan controlled sodium to air heat exchanger system design for fail-safe and passive decay heat removal (DHR). The proposed system uses a fan to control airflow and heat removal during normal operation, and when fan trips due to loss of power or a trip signal, DHR gets enabled in a fail-safe mode. The system is analyzed with the help of a 1D model as well as Computational Fluid Dynamics software. It is found from analysis that it is possible to control the air flow to about 5 to 10\% of full flow as in the case of conventional dampers to minimize heat loss during normal reactor operation. Reliability of the proposed system is also analyzed and shown that the proposed system has a much better reliability compared to the conventional passive DHRS