Stretch out operation, a practice at the conclusion of a nuclear power plant cycle, entails the introduction of positive reactivity to sustain reactor power by systematically reducing the primary loop coolant temperature and core power output. This paper delves into a comprehensive analysis of the reactivity balance and control strategies for both primary and secondary loops during such operations, drawing from the practical experience of Unit 2 at a nuclear power plant during its fifth fuel cycle. Furthermore, it explores the thermal efficiency fluctuations observed during a stretch out operation period, particularly those influenced by typhoon conditions. Building upon the control characteristics of the unit’s axial power deviation at the end of its cycle life, the paper proposes optimized power control strategies to enhance operational stability and efficiency.