EVALUATION OF ASEISMATIC INTEGRITY IN HTT R CORE-BOTTOM STRUCTURE .6.DYNAMIC STRENGTH OF GRAPHITE COMPONENT UNDER STRESS-CONCENTRATION CONDITION

In order to clarify the dynamic strength characteristics of a graphite component under stress concentration condition, the static and dynami c fracture tests were performed using scale-model specimens of the com ponent. The strain rate applied to the specimens was around 10(-5) l/s in the static test and 1 to 5 l/s in the dynamic test. As a result of the experiment, it was found that the ratio of the dynamic strength t o the static one depends on the stress gradient in the specimen;the sp ecimen with higher stress gradient shows a higher value of the strengt h. Moreover, it was also found that there is a critical stress gradien t at which the strength ratio reaches almost a constant value even if the stress gradient increases in the specimens.