Document: NRC Regulatory Guide
Document ID: c55ba6c5-aa2d-4ad6-aba2-2001e16524ab
Document Type: regulatory_guide
Title: Ultrasonic Testing of Reactor Vessel Welds During Preservice and Inservice Examinations (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A015.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.150
CFR Part: 
CFR Title: 

Content:
lse length and voltages can be observed on an oscilloscope. The calibrated time base does not necessarily have to follow the time base of the distance-amplitude correction (DAQ curve bit may be chosen to suitably characterize the initial pulse. The pulse shape record will assist in analyzing potential differences in flaw response between successive examinations (i.e., is the difference due to flaw growth or system change). Pulse shape is best determined by using a high-impedance oscilloscope with the transducer disconnected from the instrument. 2. CALIBRATION According to Appendix I, Article I, 1-4230, Section XI of the ASME Code, 1974 edition, instrument calibration for 1"Ultrasonic Reinspection of Pilgrim 1 Reactor Vessel Nozzle N2B," John H. Gieske, NUREG-6502. 2"Summary Hatch Nuclear Plant Unit I Reactor Pressure Vessel Repair," 1972, Georgia Power Company. 3"Summary of the Detection and Evaluation of Ultrasonic Indications - Edwin Hatch Unit 1 Reactor Pressure Vessel," January 1972, Georgia Power Company. 4 Round robin tests conducted by the Pressure Vessel Research Committee (PVRC) of the Welding Research Council for UT of thick section steels. , performance characteristics (amplitude linearity and amplitude control linearity) is to be verified at the beginning -of each day of examination. Requirements in Article 4,4 Section V, 1977 edition, which is referenced by Section XI, for the periodic check of instrument characteristics (screen height linearity, amplitude control linearity, and beam spread measurements) for UT examination of reactor pressure vessels have been relaxed. The interval between periodic checks has been extended from a period of 1 day to a period of extended use or every 3 months, whichever is less. This change has not been justified on the basis of statistically significant field data. Performance stability of automated electronic equipment is dependent on system performance parameters (essential variables), and the ASME Code has no quality