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Title: Short cracks in piping and piping welds

Technical Report ·
DOI:https://doi.org/10.2172/5895215· OSTI ID:5895215

This is the first semiannual report of the US Nuclear Regulatory Commission's Short Cracks in Piping and Piping Welds research program. The program began in March 1990 and will extend for 4 years. The intent of this program is to verify and improve fracture analyses for circumferentially cracked large-diameter nuclear piping with crack sizes typically used in leak-before-break analyses or in-service flaw evaluations. Only quasi-static loading rates are evaluated since the NRC's International Piping Integrity Research Group (IPIRG) program is evaluating the effects of seismic loading rates on cracked piping systems. Additional efforts involve investigating phenomena discovered during the course of conducting the Degraded Piping program. These include the evaluation of the occurrence of unstable crack jumps in ferritic steels at LWR temperatures, and the occurrence of anisotropic fracture properties causing helical crack growth. Both of these phenomena may affect the safety margins implicit in LBB analyses. Other investigations deal with the fracture behavior of bi-metallic welds, and improvements in crack opening area analyses used in LBB. Since much of the work in this program was just beginning during this first reporting period and progress is limited, a complete statement of work for the whole program is provided in this report. 42 refs., 14 figs., 11 tabs.

Research Organization:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; Battelle, Columbus, OH (USA)
Sponsoring Organization:
USNRC; Nuclear Regulatory Commission, Washington, DC (USA)
OSTI ID:
5895215
Report Number(s):
NUREG/CR-4599-Vol.1-No.1; BMI-2173-Vol.1-No.1; ON: TI91012463
Country of Publication:
United States
Language:
English