Evaluation of defect number density in sodium equipment stainless steel welds

Toyota, Kodai ; Hashidate, Ryuta ; Yada, Hiroki ; Takaya, Shigeru  ; Miyakoshi, Hiroyuki; Kato, Shoichi 

Probabilistic fracture mechanics (PFM) evaluation requires information on the probabilistic distributions of the number and size of initial defects, material properties such as crack growth rate due to fatigue and creep, and load to evaluate the failure probability of components. In this study, ultrasonic testing was conducted on the welds of the test equipment used in the research and development of fast reactors, and the number and size of defects were evaluated. The results could be used as conservative values of initial defects, and the values related to initial defects for PFM evaluation of FBR components were examined.