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:
introduces an error band in the calibra- tion process. The error band may depend on, among others, the following factors: (1) Drift due to ambient temperature change. (2) Drift due to high temperature storage. (3) Drift due to high humidity storage. (4) Drift due to vibration and shock loading during shipment. (5) Degradation of the memory device used to store the reference signal information due to vibra- tion, shock, aging, or heat effects. To ensure stability, computer systems are generally kept in an air conditioned environment; however, EBS systems are not usually kept in a controlled environment. Error band for one particular type of instruments was determined to be in the range of +6 percent. The error band for other instruments may be in a different range and may vary for the same instrument if memory devices or components of different quality are used at a later date. The error band is dependent on the temperature extremes, shock loadings, and vibrations suffered by the instrument. Since the error band value depends on these parameters, it would be advisable to ensure, throu gh recording instruments, that the EBS was not subjected to higher temperatures (container lying in the sun) and greater shock (container 5"Calibration Verification of Ultrasonic Examination Systems with the Electronic Block Simulator," D. J. Boomgard et al., August 1979, Report No. WCAP-9545, Westinghouse Electric Corporation, Nuclear Service Division, P.O. Box 2728, Pittsburgh, PA 15230. dropped) during transport than those parameters that served as a basis for defining the error band. Use of electronic simulators would be permissible if they can check the calibration of the UT system as a whole and the error band introduced by their use can be relied on and taken into consideration. d. Static Versus Dynamic Reflector Responses With some automated systems, the DAC curve is manually established. In these cases, the signal is maximized by optimizing the transducer orientation toward the