Due to the volatility of electrical power demand power plants are increasingly forced to run at varying
utilization levels. Besides typical daily cycles in recent times, the variable supply from regenerative energy
sources causes additional fluctuations. Power plants which were originally intended to provide the base load are frequently shut down and powered up V ariations in the steam temperature accompanying the power changes induce thermo-mechanical stresses in thick-walled components, which lead to material fatigue and superimposed creep, and consequently can cause failure. With respect to modern power plants and also for still