Document: NRC Regulatory Guide
Document ID: a4944d20-ef6e-480b-a45d-14425bedd2e5
Document Type: regulatory_guide
Title: ASME Code Cases Not Approved for Use (Rev. 8)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2219/ML22196A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.193
CFR Part: 
CFR Title: 

Content:
of concerns with the proposed conditions. Because of the number of issues raised by the NRC staff and because of the concerns expressed in the public comments, the NRC determined that a more effective approach for developing a suitable performance demonstration program was to work with ASME International to resolve the issues. Accordingly, the NRC is not going to endorse Code Case N-659 or Code Case N-659-1 at this time. The NRC staff continues to interact with the cognizant ASME committees, and the industry is working to provide additional data and information. 9/17/02 11/18/03 N-659-2 Use of Ultrasonic Examination in Lieu of Radiology for Weld Examination, Section III, Divisions 1 and 3 The NRC is not going to endorse Code Case N-659-2 at this time. Research is currently being conducted on a number of issues with respect to using ultrasonic testing (UT) to replace radiographic testing (RT). Although preliminary results suggest that replacing RT with UT may be feasible, the interchangeability of these techniques has not yet been fully demonstrated, UT acceptance criteria for fabrication/construction weld inspection have not yet been adequately defined, and the applicability of UT in the presence of high levels of acoustic noise such as that found in austenitic materials is not fully understood. The impact and implications of the expanded examination volume (full thickness) required for UT for fabrication/construction must also be addressed. In addition, the Code Case would allow the examinations to be performed in accordance with Section V, Article 5, up to and including the 2001 Edition, or Article 4 for a later edition and addenda. The reliability UT performed under the provisions of Section V, has been shown to be inferior to UT techniques developed through a program under which the performance characteristics have been shown to be sufficient and reliable. Furthermore, the qualification specimens do not specify an adequate number of flaws required for the sample