The supercritical carbon dioxide(S-CO2) coal-fired power generation system is a significant way to improve the efficiency and realize the rapid peaking of coal-fired power generation. However

under rapid peaking conditions

the S-CO2 cooling wall experiences significant creep and fatigue damage. This paper addresses the comprehensive characterization of cooling wall tubes during variable load peaking. A steady-state multi-field coupled three-dimensional model of S-CO2 cooling wall and a cooling wall damage model for transient variable load process are established. The validity of model is verified through experimental data. The steady state characteristics of the S-CO2 cooling wall and the variation rules of temperature

stress

fatigue and creep damage in the transient process of variable load are obtained. The influence of load variation rate on cooling wall tube damage is investigated. Through systematic analysis of load variation rates

this paper proposes a quadratic-function-based load modulation strategy to optimize the coordination between load variation rate and system demand. Compared with the constant variable load rate

the proposed control method decreases maximum fatigue damage by 16.95% and reduces peak creep damage by 19.84%. This novel approach significantly reduces the cooling wall temperature rise rate

peak temperature

and associated fatigue-creep damage

while enhancing operational flexibility and safety.