Crack Growth Evaluation for Small Cracks in Reactor Coolant Piping

Technical Report · Fri Apr 01 04:00:00 EST 1983

DOI:https://doi.org/10.2172/1086280· OSTI ID:1086280

Simonen, F. A. ^[1]; Mayfield, M. E. ^[1]; Forte, T. P. ^[1]; Jones, D. ^[1]

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1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

This report describes an evaluation of fatigue crack growth in Pressurized Water Reactor (PWR) piping. The results provide supporting data to a research program for the U.S. Nuclear Regulatory Commission (NRC) at the Pacific Northwest Laboratory which has the objective of evaluating the effectiveness and reliability of inservice inspection of primary coolant piping. The crack growth calculations described here were performed after a review and refinement of input parameters to a previous study entitled "Cold Leg Integrity Evaluation." Less conservative estimates of initial flaw size, crack growth rate curves, and stress transients resulted in a significant increase in predicted life for flawed piping over the results of the original study. Except for the charging inlet nozzle analysis, all locations of postulated cracking had predicted lives well in excess of the 40-year design life. A detailed comparison is made with published probabilistic fracture mechanics calculations. The deterministic predictions of long fatigue life are shown to be consistent with predicted low failure probabilities for PWR primary coolant piping. The two analysis approaches together indicate that present inspection rules are adequate to detect in primary coolant piping the fatigue crack growth caused by design stress transients.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE; USNRC
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 1086280
• Report Number(s): PNL--4642; NUREG/CR-3176
• Country of Publication: United States
• Language: English