Midland reactor pressure vessel flaw distribution
- Failure Analysis Associates, Inc., Menlo Park, CA (United States)
- Sandia National Labs., Albuquerque, NM (United States)
The results of laboratory nondestructive examination (NDE), and destructive cross-sectioning of selected weldment sections of the Midland reactor pressure vessel were analyzed per a previously developed methodology in order to develop a flaw distribution. The flaw distributions developed from the NDE results obtained by two different ultrasonic test (UT) inspections (Electric Power Research Institute NDE Center and Pacific Northwest Laboratories) were not statistically significantly different. However, the distribution developed from the NDE Center`s (destructive) cross-sectioning-based data was found to be significantly different than those obtained through the UT inspections. A fracture mechanics-based comparison of the flaw distributions showed that the cross-sectioning-based data, conservatively interpreted (all defects considered as flaws), gave a significantly lower vessel failure probability when compared with the failure probability values obtained using the UT-based distributions. Given that the cross-sectioning data were reportedly biased toward larger, more significant-appearing (by UT) indications, it is concluded that the nondestructive examinations produced definitively conservative results. In addition to the Midland vessel inspection-related analyses, a set of twenty-seven numerical simulations, designed to provide a preliminary quantitative assessment of the accuracy of the flaw distribution method used here, were conducted. The calculations showed that, in more than half the cases, the analysis produced reasonably accurate predictions.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States); Failure Analysis Associates, Inc., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10120657
- Report Number(s):
- SAND--93-7064; ON: DE94006350; BR: GB0103012; CNN: CONTRACT AA-7600 RP-2975-19
- Country of Publication:
- United States
- Language:
- English
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210200
COMPUTER CODES
DEFECTS
DISTRIBUTION FUNCTIONS
FAILURES
FRACTURE MECHANICS
MIDLAND-1 REACTOR
MIDLAND-2 REACTOR
NUMERICAL ANALYSIS
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
NONBOILING WATER COOLED
PRESSURE VESSELS
PROBABILITY
ULTRASONIC TESTING