Session: CS-07-04 Recent Developments in ASME Codes and Standards - 4 (with CS-08)

Paper Number: 179681

179681 - Fatigue Crack Growth Behavior at Low Stress Intensity Factor Range for Reactor Pressure Vessel Steel in Water Environment for the Asme Code Section Xi 

Abstract: 

The reference fatigue crack growth rate da/dN of ferritic steels characterized in terms of the applied stress intensity factor range is provided in Nonmandatory Appendix Y in the ASME Boiler and Pressure Vessel Code Section XI. The reference fatigue crack growth rate curves in the Appendix Y are given in both air and light water reactor environments, and the fatigue crack growth rate in water environment are generally higher than that in air environment at the same stress intensity factor range. However, in the low stress intensity factor range near the threshold, the crack growth rate in air environment is higher than that in right water reactor environment. According to ASME Boiler and Pressure Vessel Code Sec. XI, either of the higher fatigue crack growth rates in air or light water reactor environments is to be used for fatigue crack growth calculation for light water reactor environment. In this study, sample calculations of fatigue crack growth in light water reactor environments were performed in the region of low stress intensity factor range to investigate the effect of using the reference fatigue crack growth rate for the air environment instead of the reference fatigue crack growth rate for the right water reactor environment on the total crack growth amount.

Presenting Author: Yoshihito Yamaguchi Japan Atomic Energy Agency

Presenting Author Biography: Author joined Japan Atomic Energy Agency in 2008. He has studied the structural integrity assessment considering the age-related degradation mechanisms of pipes since joining the company. Currently, he has been developing a probabilistic fracture mechanics analysis codes PASCAL series for the seismic fragility evaluation on aged piping of nuclear power plants.

Authors:

Yoshihito Yamaguchi Japan Atomic Energy Agency
Kunio Hasegawa Japan Atomic Energy Agency