Stability analysis on flow parameters in coolant temperature control system of lead-cooled fast reactor

•A simplified coolant system model of LFR has been established and verified.•A qualitative analysis of coolant flow with Lyapunov First Method has been completed.•The feed-water flow in secondary loop has significant effect on system stability.•A complete quantitative stability degree analysis program is designed and applied.•Higher Rw and lower Rc can increase real stability radius to improve system stability.