HEATUP AND COOLDOWN RATE LIMITS
The important information in this chapter is summarized below.
Heatup-Cooldown Rate Limits Summary
Heatup and cooldown rate limits are based upon impact on the future fatigue life
of the plant. The heatup and cooldown rate limits ensure that the plant's fatigue
life is equal to or greater than the plant's operational life.
Large components such as flanges, reactor vessel head, and the vessel itself are the
Usually exceeding the heatup or cooldown rate limits requires only an assessment
of the impact on the future fatigue life of the plant.
May be required when heating large components
Used to minimize thermal stresses by controlling the heating rate
Become very significant if system is at room temperature or below and
very close to RTNDT temperature limitations