Abstract: In the two 1000MW ultrasupercritical units of a certain power plant project phase I, the P92 steel ID 349mm×72mm main steam pipe was adopted. The operation safety and life of this thin walled pipe attracted a lot of attention. With the help of fullload spectrogram of actual pipe damage obtained from the constructed condition monitoring and life safety management system, aiming at the laws of two material creep damage conventional longtime strength and lower boundary longtime strength, considering two wall thickness thin wall and thick wall, the operation safety and expected service life of P92 steel main steam pipe under the conditions of several combinations were analyzed and researched.

Key words: full-load spectrogram, main steam pipe, operation safety, life research