If the temperature gradient exceeds a certain level, fatigue could induce localised structural damage causing some components to creep and crack. More pronounced load variations, such as steep changes of reactor power level (up to ±20% Pr with the speed of 10% Pr per minute) or load following in the power range between 50% Pr to 100% Pr (with ramping rates of less than 5% Pr per minute) are limited to 20 000 cycles in the reactor lifetime. In addition, preventive measures, such as the automatisation of operation control, have already been taken in order to mitigate the impact of load following on material fatigue. Continuous monitoring of equipment fatigue (temperature measurements, non-destructive material tests) is routinely performed, especially on safety-related components.