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:
eliminate unnecessary repairs. The radiation exposure during repairs is usually many times the exposure during examination, so a net reduction in radiation exposure is expected. h. Reducing margins of error in estimates of flaw growth and thus helping reduce overconservative estimates and decisions on flaw acceptance. i. Providing more consistent UT procedures for flaw characterization, thereby leading to procedures that ensure lower probability of missing large flaws and ensuring greater safety for the public, industrial workers, and government employees. 1.3.3.2 Impact. There will be major impact in the following three areas: a. Quality control of the UT equipment At present, requirements in the ASME Code for quality control of UT equipment are marginal; for example, there are no direct requirements to control the quality of UT transducers. Criterion XII, "Control of Measuring and Test Equipment," of Appendix B, "Quality Assur- ance Criteria for Nuclear Power Plants and Fuel Repro- cessing Plants," to 10 CFR Part 50 requires, in part, that measures be established to ensure that instruments used in activities affecting quality are properly controlled, calibrated, and adjusted at specified periods to maintain accuracy within necessary limits. The recommendations of this guide will help to bring about uniformity in the quality control procedures among different companies and will ensure that quality control measures arc taken to ensure reliability and reproducibility of UT results. No new UT equipment will be needed to follow the recommendations of this guide. However, the quality control measures recommended for UT equipment will impose extra cost burdens that are difficult to estimate without feedback from industry. b. Increase in examination time 4 This guide would recommend, for the first time, that indications with significant length of indication travel (larger than the standard calibration holes) or with significant depth dimensions be recorded. It is not