A study on the specimen size effect of fracture resistance curve of nuclear piping materials

In determining a fracture resistance curve (J-R curve), the effect of specimen size must be considered. An extensive research is currently underway in nuclear industry to quantify this constraint effect including size, non-dimensional crack length etc. The objective of present paper is to investigate the relationship between the specimen size and the fracture resistance (J-R) curve. The final goal is to apply this relationship to leak-before-break analysis of nuclear piping systems. An experimental study on the effect caused by specimen size variation was carried out with base metal of SA515 Gr. 60 carbon steel and SA516 Gr. 70 carbon steel and weld metal of SA516 Gr. 70 carbon steel and SA312 TP347 stainless steel. The fracture toughness test was performed by the single specimen technique in accordance with SATM E1152-87. The effect of specimen size and the influences were investigated and discussed. (author)