Document: NRC Regulatory Guide
Document ID: 1bd47be4-b79c-4108-b744-3e7d400266e8
Document Type: regulatory_guide
Title: ASME Code Cases Approved for Use Without Conditions (Rev. 0)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2509/ML25091A013.pdf
Revision Date: 2025-09
Chapter: 
Section ID: RG-1.262
CFR Part: 
CFR Title: 

Content:
sed alternatives in 10 CFR 50.55a(z) or specific exemptions in 10 CFR 50.12, “Specific Exemptions,” as applicable. ASME may annul a code case because its provisions have been incorporated into the BPV Code or OM Code, the application for which it was specifically developed no longer exists, experience has shown that the design analysis or construction method is no longer required, or experience has shown that an examination or testing method is no longer adequate. After ASME annuls a code case and after the NRC amends 10 CFR 50.55a and this guide, applicants and licensees may not implement that code case for the first time. However, a licensee that implemented the code case before its annulment may continue to use that Section XI or OM code case through the end of the present code of record interval and may continue to use that Section III code case until it voluntarily updates its Section III Code of Record. An annulled Section XI or OM code case cannot be used in the subsequent code of record interval unless it is implemented as an approved alternative under 10 CFR 50.55a(z) or as a specific exemption under 10 CFR 50.12. If the NRC incorporated a code case by reference into 10 CFR 50.55a and ASME later annulled it because experience has shown that the design analysis, construction method, examination method, or testing method is inadequate, the NRC would amend 10 CFR 50.55a and this guide to remove its approval of the annulled code case. Applicants and licensees should not begin to implement such annulled code cases in advance of the rulemaking. Notwithstanding these requirements, the Commission may impose new or revised ASME BPV and OM Code requirements, including implementation schedules, that it determines are consistent with 10 CFR 50.109, “Backfitting.” RG 1.262, Page 5 ASME may revise a code case, for example, to incorporate user experience. The licensee or applicant may not apply the older or superseded version of the code case unless it was applied