[2E01-07] Advanced Technologies of Design, Management & Evaluation for Nuclear Plants

[2E02] Development of failure mitigation technologies for improving resilience of nuclear structures

(2)Study on Initiation and Propagation of Local Failure at Structural Discontinuities of Nuclear Components

*Kensuke Narumi¹, Naoto Kasahara¹, Takuya Sato¹, Yoshiki Tsunemoto² (1. UTokyo, 2. UTokyo(Currently CRIEPI))

Keywords:structural discontinuities, local failure, ductile fracture, fracture surface, stress triaxiality, large deformation elastic and plastic analysis

In order to clarify the behavior of local failure in the reactor vessels, the nozzle junction part of a vessel was studied by a failure experiment and an analysis. The purpose of this study is to apply the new fracture surface, to clarify effects of nozzle shape on the failure mode, and to propose a method to directly analyze the initiation and propagation of fracture. In conclusion, effects of the rigidity ratio of the nozzle part and the circular plate part and the rate of change of rigidity on the change of the failure mode was clarified. In addition, a fracture surface was applied to enable direct analysis of the initiation and propagation of ductile fracture and local failure.