Document: NRC Regulatory Guide
Document ID: a1541707-8144-409c-8842-4ea7d4b8ef4e
Document Type: regulatory_guide
Title: 10/2019 (Rev. 19)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1912/ML19128A244.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.147
CFR Part: 
CFR Title: 

Content:
SME Section XI Code Cases. When a licensee initially applies a Code Case listed in Tables 1 or 2 of this guide, it must implement the most recent version of that Code Case incorporated by reference in 10 CFR 50.55a. ASME may annul a Code Case because its provisions have been incorporated into the Code, the application for which it was specifically developed no longer exists, 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, 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 Code Case through the end of the present ISI interval. An annulled Code Case cannot be used in the subsequent ISI interval unless it is implemented as an approved alternative under 10 CFR 50.55a(z). If the NRC incorporated a Code Case by reference into 10 CFR 50.55a and ASME later annulled it because experience has shown that an examination or testing method is inadequate, the NRC will amend 10 CFR 50.55a and this guide to remove its approval of the annulled Code Case. 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 Code requirements, including implementation schedules, that it determines are consistent with 10 CFR 50.109, “Backfitting.” RG 1.147, Rev. 19, Page 5 ASME may revise a Code Case, for example, to incorporate user experience. The licensee or applicant cannot apply the older or superseded version of the Code Case for the first time. If an applicant or a licensee applied a Code Case before it was listed as superseded, it may continue to use the Code Case until it updates its Construction Code of Record (an applicant would update its application) or until the licensee’s 120-month ISI/inservice testing (IST) update interval expires, after