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U.S. Department of Energy
Office of Scientific and Technical Information

Finite-length surface crack propagation in clad cylinders

Technical Report ·
OSTI ID:6866531

Licensing issues within the nuclear industry dictate a need to investigate the effects of cladding on the extension of small finite-length cracks near the inside surface of a vessel. Limited experimental data and analyses indicate that cladding can inhibit the propagation of certain shallow flaws. This report describes an analytical study which was carried out to determine (1) the minimum flaw depth for crack initiation under PTS loading for semicircular surface flaws in a clad reactor pressure vessel and (2) the impact, in terms of the conditional probability of vessel failure, of using a semicircular surface flaw as the initial flaw. The analytical results indicate that, for initiation, a much deeper critical crack depth is required for the finite-length flaw than for the infinite-length flaw. Probabilistic analysis of selected PTS transients produced a substantial in the conditional probability of failure for a finite-length flaw model. It is recommended that a testing program be carried out utilizing clad cruciform and clad cylindrical test specimens. The completed experimental and analytical research will provide a basis for introducing a refined treatment of surface flaw initial geometry into PT'S fracture analysis procedures. This report is designated HSST Report 129.

Research Organization:
Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Oak Ridge National Lab., TN (United States)
Sponsoring Organization:
NRC; Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6866531
Report Number(s):
NUREG/CR-5915; ORNL/TM--12166; ON: TI93003171
Country of Publication:
United States
Language:
English