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:
ta obtained from UT equipment of uncertain and unspecified performance lead to discussions and delays in the review process resulting in loss of NRC staff time and loss of plant availability and power generation capacity for the utilities. These situations definitely need to be avoided as much as possible. This guide is aimed at achieving this purpose by issuing recommendations that will be supplementary to the existing ASME Code UT procedures. The issue remains whether to wait for the development of advanced NDE techniques and continue with the present ASME Code procedures resulting in uncertainties, delays, and discussions or to encourage improvement in the present state of the art of conventional UT. The decision appears to be obvious that we should use conventional UT based on engineering judgment until some new techniques for flaw detection and sizing can be proved effective in the field. This guide is aimed at providing the recommendations needed to improve on the ASME Code UT requirements until proven advanced NDE techniques are available. E I I 1.150-20 APPENDIX TO VALUE/IMPACT STATEMENT Values that will result from this regulatory guide are much easier to perceive than the impact. It is very difficult• to assess the real impact because the kind of statistical data needed is simply not available at this time. One way in which we hope to estimate the impact is through industry feed- back after the guide has been issued. We have made an attempt, in a qualitative manner, to estimate the value/impact of regulatory guide positions, position by position, as follows: 1. INSTRUMENT PERFORMANCE CHECKS Recording the characteristics of the ultrasonic testing (UT) examination system will be useful in later analysis for determining the location, dimensions, orientation, and growth rate of flaws. System performance checks to deter- mine the characteristics of the UT system will be made shortly before the UT examinations. Each UT examination will therefore be correlated