Effects of different load variation rates on the operational stability in an S–CO2 Brayton cycle coupled natural circulation lead-cooled fast reactor

• Published in: Progress in nuclear energy (New series) 2024-10, Vol.175, p.105319, Article 105319
• Main Authors: Zhang, Shuai, Bai, Yunqing, Zhou, Xing, Li, Wenbo, Li, Yang, Li, Tingyu, Mei huang
• Format: Article
• Language: English
• Subjects: Control strategy; LFR; Load variation rate; Natural circulation; SCO2 Brayton cycle
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2024.105319

The thermal inertia results in net heat absorption in natural circulation lead-cooled reactors during power variation processes, increasing the risk of core meltdown. In this study, a dynamic simulation model of a natural circulation lead-cooled fast reactor coupled with a supercritical carbon dioxide Brayton Cycle power generation system has been developed based on Vpower. The influence of thermal inertia on system operating temperature under different power variation rates was discussed. The results indicate that during power reduction, different decline rates only affect the temperature variation range of the system without impacting the final stable state. However, during power increase, different ramp rates not only affect the temperature variation range but also lead to varying degrees of system temperature rise. To address this issue, an optimized turbine throttling scheme is proposed. Compared to the original plan, the new plan successfully stabilizes the temperature at the rated value after increasing the system power. This study provides insights for the operation control strategy of similar reactor types.