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:
ning direction does not make a difference in the sensitivity and vibration background noise received from the search unit or (2) these differences are taken into account by a correction factor. c. For mechanized scanning, signals should not be maximized during the establishment of the DAC curve. d. One of the following alternative guidelines should be followed for establishing the DAC curve: (I) The DAC curve should be established using a moving transducer mounted on the mechanism that will be used for examination of the component. (2) Correction factors between dynamic and static response should be established using full-scale mockups. (3) Correction factors should be established using models and taking scaling factors into consideration (assumed scaling relationship should be verified). (4) Correction factors between dynamic and static response should be established from the indications that are found during examination for sizing. For detection of flaws during the initial scan, correction factors may be assumed based on engineering judgment. If assumed correction factors are used for detection, these factors should later be confirmed on indications from flaws in the vessel during the examination. Deviation from the assumed value may suggest reexamining the data. 2.3 Calibration Checks If an EBS is used for calibration check, the following should apply: a. The significant DAC percentage level used for the detection and sizing of indications should be reduced to take into account the maxi mum error that could be introduced in th- system hy the variation of resistance or leakage in the connectors or other causes. b. Calibration checks should be performed on the complete connected system (e.g., transducer and cables should not be checked separately). c. Measures should be taken to ensure that the different variables such as temperature, vibration, and shock limits for which the EBS error band is determined are not exceeded during transport, use, storage, etc. d. When