Fracture evaluation of an in-service piping flaw caused by microbiologically induced corrosion

Book · Sun Dec 01 04:00:00 EST 1996

OSTI ID:403210

Rudland, D L; Scott, P M; Wilkowski, G M ^[1]; Rahman, S ^[2]

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1. Battelle, Columbus, OH (United States)
2. Univ. of Iowa, Iowa City, IA (United States)

A pipe fracture experiment was conducted on a section of 6-inch nominal diameter pipe which was degraded by microbiologically induced corrosion (MIC) at a circumferential girth weld. The pipe was a section of one of the service water piping systems to one of the emergency diesel generators at the Haddam Neck (Connecticut Yankee) plant. The experimental results will help validate future ASME Section XI pipe flaw evaluation criteria for other than Class 1 piping. A critical aspect of this experiment was an assessment of the degree of conservatism embodied in the ASME definition of flaw size. The ASME flaw size definition assumes a rectangular shaped, constant depth flaw with a depth equal to its maximum depth for its entire length. Since most service flaws are irregular in shape, this definition may be overly conservative. Results from several fracture prediction models are compared with the experimental results. These results show that, for this case, the ASME Appendix H criteria significantly underpredicted the experimental maximum moment, while other fracture prediction models provided good predictions when accurate pipe, weld and flaw dimensions were used.

• OSTI ID: 403210
• Report Number(s): CONF-960706--; ISBN 0-7918-1770-9
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
AUXILIARY WATER SYSTEMS
BIOLOGICAL FOULING
COMPARATIVE EVALUATIONS
CONNECTICUT YANKEE REACTOR
DEFECTS
EXPERIMENTAL DATA
FRACTURE MECHANICS
MECHANICAL TESTS
PIPES
RELIABILITY
WELDED JOINTS