Document: NRC Regulatory Guide
Document ID: 83589d93-c6fc-479f-bebb-e115953f8c09
Document Type: regulatory_guide
Title: Containment Isolation Provisions for Fluid Systems + HISTORY –HISTORY 10/2015 – Periodic Review of Revision 1 – Reviewed with issues identified for future consideration
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1523/ML15236A283.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.141
CFR Part: 
CFR Title: 

Content:
Systems Office/division/branch: NRR/DSS/SCVB Technical Lead: Jerome Bettle Staff Action Decided: Reviewed with Issues identified for Future Consideration 1. What are the known technical or regulatory issues with the current version of the Regulatory Guide (RG)? RG 1.141, Revision 1, was issued in July 2010. This RG describes methods the Nuclear Regulatory Commission (NRC) staff finds acceptable for complying with Title 10 of the Code of Federal Regulations Part 50, Appendix A, “General Design Criteria for Nuclear Power Plants.” Revision 1 of this RG endorses the American Nuclear Society (ANS)/American National Standards Institute (ANSI) standard ANS 56.2/ANSI N271-1976 as did the initial issuance of the RG in April 1978. The ANS 56.2 working group revised N271 and issued ANSI/ANS-56.2-1984. The ANSI/ANS-56.2-1984 revision was determined to be adequate by the working group and found to contain additional guidance for containment isolation provisions, including diversity of actuation parameters and the concept of phased isolation. ANSI/ANS-56.2-1984 was reaffirmed in 1989, but with the subsequent disbanding of the ANS 56.2 working group, ANSI identifies the status of this guidance document as “withdrawn.” In preparing the RG 1.141, Revision 1, in 2009/2010, the NRC staff noted that the additional guidance provided was limited, covered elsewhere in industry standards and guidance, and that the staff’s Regulatory Positions contained in the original issue of the RG were for the most part not included. Therefore, for Revision 1 of RG 1.141, the staff decided that the RG revision would continue to endorse N271-1976 and include the same Regulatory Positions in order to keep the revision effort as simple as possible while adopting the updated RG format and “boilerplate” content. For the above reasons, any future revision of the RG 1.141 should adopt ANSI/ANS-56.2-1984, or a newer revision if available, with associated exceptions and clarifications. This change