Specimen size effect on fracture toughness of reactor pressure vessel steel following warm pre-stressing

Iwata, Keiko ; Tobita, Toru; Takamizawa, Hisashi ; Chimi, Yasuhiro; Yoshimoto, Kentaro*; Nishiyama, Yutaka 

The effect of warm pre-stressing (WPS) on fracture toughness was evaluated for a reactor pressure vessel steel. Various types of thermomechanical loadings were applied to 1T-CT specimens. The results were compared with predictions from several analytical WPS engineering models. The specimen size effect was subsequently investigated under the load-unload-cool-fracture transient condition using 1T-, 0.4T-, and 0.16T-CT specimens. Analyses of the plastic zone distribution and residual stress were conducted to identify the difference in the WPS effect among the specimens.