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:
he use of holography, synthetic aperture imaging technique, or acoustic emission, all of which are still in the stage of proto- type development and have not been proved effective for field use, would not be justifiable on the basis of either cost or effectiveness. 2.4 Comparison of Procedural Alternatives Leaving the situation as it is would mean that continued attention and manpower would have to be devoted by the NRC staff to investigate the uncertainties associated with flaw growth on a case-by-case basis. The low level of confidence in the present techniques means that excessive margins would continue to be used in the flaw-acceptance criteria. Also, unnecessary cutting and repair attempts to remove suspected flaws may result. The procedures recommended in this guide have been shown to be effective in practice, although they are not in general use in the United States. Including these procedures as regulatory guide recommendations should result in their wider use and consequently their improvement. After these procedures have been accepted by the industry, we will seek their inclusion in the ASME Code. Some of these procedures have already been sent to the ASME for considera- tion and inclusion in the present ASME Code procedures for ultrasonic examinations. 2.5 Decision on Technical and Procedural Alternatives On the basis of the above, it appears desirable to issue a regulatory guide to provide recommendations for improving ASME Code procedures. These recommendations, which are based on the advanced state-of-the-art UT procedures in current use by some organizations, would improve the ability to detect and characterize flaws without imposing new, unproved techniques for flaw detection on industry. 3. STATUTORY CONSIDERATIONS 3.1 NRC Authority The authority for this guide is derived from the safety requirements of the Atomic Energy Act of 1954, as amended, and the Energy Reorganization Act of 1974, as implemented by the Commission's regulations. In particular,