Comparative study on sequential and simultaneous startup performance of space nuclear power system with multi brayton loops. (October 2022)

• Record Type: Journal Article
• Authors: Ma, Wenkui; Ye, Ping; Gao, Yue; Yang, Xiaoyong
• Is Part Of: Acta astronautica. Volume 199(2022)
• Page Start: 142
• Page End: 152
• Publication Date: 2022-10
• Subjects: Space reactor -- Brayton cycle -- Multi brayton loops -- Startup; Astronautics -- Periodicals; Outer space -- Exploration -- Periodicals; Astronautics; Periodicals; 629.405
• DOI: 10.1016/j.actaastro.2022.07.023
• Languages: English
• ISSNs: 0094-5765

Abstract

Abstract: The closed Brayton cycle is an ideal energy conversion technology for high-power space nuclear power system (SNPS) because of its small volume, light weight, and stable operation. To increase the redundancy of the system, a SNPS with multi Brayton loops (SNPS-MBL) is adopted. Startup performance is an essential part of the off-design performance of SNPS-MBL. In this study, the thermal-hydraulic model of the SNPS-MBL was established. Two startup schemes, simultaneous startup and sequential startup, for SNPS with dual Brayton loops (SNPS-DBL) were formulated and the performance of the two schemes were compared. The results indicated that motoring power of external power source (EPS) was required to drive the rotation of the shaft at the initial startup stage. And the simultaneous startup of SNPS-DBL was stable and less time-consuming, but the motoring power of EPS was high; the motoring power of sequential startup scheme was less than that of simultaneous startup, but the coupling effect between Brayton loops led to the fluctuation of gas inventory and power in Brayton loop (BL), which is easy to cause the instability of the system. Furthermore, the influence mechanism of space environment temperature on sequential and simultaneous startup schemes were analyzed. The results showed that the environment temperature impacted the coupling effects of multi BLs during sequential startup. Elevated environment temperature redistributed coolant inventories between BLs during sequential startup and changed power of EPS and startup time of the two startup schemes. This study provides a reference for the design and operation of SNPS-MBL. Highlights: The performance of space nuclear power system (SNPS) under different startup schemes were compared and studied. The coupling effects between Brayton loops (BL) during sequential startup scheme were evaluated. The demand of external power supply of sequential startup is less than that of simultaneous startup. The change of space environment temperature impacts the coupling effect between BLs during sequential startup.