Fatigue Crack Growth Analysis of Internal Surface Crack on Pressure Vessels
Zhi-jie Li , Geng-yu Zhou , Guang-chen Jiao , Chun-lei Ma 
 Consys Group Limited
 Suzhou Nuclear Power Research Institute
18th National Conference on Fatigue and Fracture (NCFF2016), Zhengzhou, China, April 2016
The reactor pressure vessels are important parts in nuclear power plants, the integrity of which is a barrier for the reactor safety. Small cracks would generate with the reactor running and the complex conditions in the reactor would cause fatigue crack growth. The pressure vessel cannot be replaced during its service life, so the fatigue crack growth should be considered in an accurate or conservative way to ensure the size of the crack are under limit. In addition, the calculation of fatigue crack growth is necessary in life extension program for old nuclear power plants. Meanwhile, simulating the whole process from a surface crack to a through-wall crack is helpful and useful in LBB evaluation. In a word, crack growth analysis is very important.
In this paper, the whole growth process of internal surface crack in the circumferential direction on the pressure vessel under fatigue loads is simulated on the basis of Zencrack and parameters in the whole process are monitored such as stress intensity factor, J integral. The specific value of the parameters in the whole growth process are achieved. This analysis provides a practicable method for the design and safety evaluation when taking cracks of the pressure vessel into consideration, the life extension evaluation of old power plant and LBB evaluation.