Ultrasonic Phased Array Evaluation of Control Rod Drive Mechanism (CRDM) Nozzle Interference Fit and Weld Region
In this investigation, non-destructive and destructive testing were used to evaluate potential boric acid leakage paths around an Alloy 600 CRDM penetration (Nozzle 63) from the North Anna Unit 2 reactor pressure vessel head that was removed from service in 2003. For this investigation, Nozzle 63 was examined using phased array ultrasonic testing. Prior to examining Nozzle 63, a CRDM penetration mockup with known notches and boric acid deposits was used to assess probe sensitivity, resolution and calibration. Following the non-destructive testing of Nozzle 63, the nozzle was destructively examined to visually assess the leak paths. These destructive and nondestructive results are compared and results are presented. The results of this investigation may be used by NRC to evaluate licensees’ volumetric leak path assessment methodologies and to support regulatory inspection requirements.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1076727
- Report Number(s):
- PNNL-SA-86470; 401001060
- Country of Publication:
- United States
- Language:
- English
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Ultrasonic Phased Array Assessment of the Interference Fit and Leak Path of the North Anna Unit 2 Control Rod Drive Mechanism Nozzle 63 with Destructive Validation