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:
mecha- nized equipment. Each on-site periodic calibration should be preceded by complete system per- formance verification using a minimum of two (2) target reflec- tors separated by a distance repre- senting 75 percent of maximum thick- ness to be examined. b. Written records of calibra- tions should be established for both target reflector responses and Code calibration block DAC curves for each transducer. These written records may be used to monitor drift since the original recorded calibration. c. Measures should be taken to ensure that the different variables such as temperature, vibration, and shock limits are minimized by controlling packaging, handling, and storage. I I1 is 1.150-12 2.4 Calibration Blocks 3.1 Internal Surface Calibration blocks should comply with Appendix I to Section XI or Article 4, Section V of the ASME Code. When an alternative calibra- tion block or a new conventional block is used, a ratio between the DAC_ curves obtained from the original block and from the new block should be noted (for reference) to provide for a meaning- ful comparison of previous and current data. The calibration side-drilled holes in the basic calibration block and the block surface should be protected so that their characteristics do not change during storage. These side- drilled holes or the block surface should not be modified in any way (e.g., by polishing) between successive examinations. If the block surface or the calibrat1i-on reflector holes have been po1li'shed by any chemical or mechanical means, this fact should I be recorded. 3. EXAMINATION The scope and extent of the ultrasonic examinations should comply with IWA-2000, Section XI of the ASME Code. If electronic gating is used to define the examination volume within which indications are recorded, the start and stop control points should include the entire required thickness including the material near each surface. If a single gate is used, it should be capable of recording multiple indications