Document: NRC Regulatory Guide
Document ID: c458fb43-5ee6-4e14-a33d-808ec974115a
Document Type: regulatory_guide
Title: Instrument Lines Penetrating Primary Reactor Containment + HISTORY - HISTORY 09/2009 – DG-1225 , Proposed Revision 1 Prior to the issuance of Revision 1, RG 1.11 was entitled "Instrument Lines Penetrating Primary Reactor Containment (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0909/ML090970530.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.11
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CFR Title: 

Content:
U.S. NUCLEAR REGULATORY COMMISSION September 2009 OFFICE OF NUCLEAR REGULATORY RESEARCH Division 1 DRAFT REGULATORY GUIDE Contact: J. Bettle (301) 415-1314 DRAFT REGULATORY GUIDE DG-1225 (Proposed Revision 1 of Regulatory Guide 1.11, dated March 1971) INSTRUMENT LINES PENETRATING THE PRIMARY REACTOR CONTAINMENT A. INTRODUCTION General Design Criterion (GDC) 55, “Reactor Coolant Pressure Boundary Penetrating Containment,” and GDC 56, “Primary Containment Isolation,” of Appendix A, “General Design Criteria for Nuclear Power Plants,” to Title 10, Part 50, “Domestic Licensing of Production and Utilization Facilities,” of the Code of Federal Regulations (10 CFR Part 50) (Ref. 1) establish that a plant’s principal design criteria require, in part, that each line that penetrates the primary reactor containment and that is part of the reactor coolant pressure boundary or connects directly to the containment atmosphere has at least one locked, closed isolation valve or one automatic isolation valve inside containment, and at least one locked, closed isolation valve or one automatic isolation valve outside containment (a simple check valve may not be used as the automatic isolation valve outside containment) “unless it can be demonstrated that the containment isolation provisions for a specific class of lines, such as instrument lines, are acceptable on some other defined basis.” This guide defines a basis that the staff of the U.S. Nuclear Regulatory Commission (NRC) considers acceptable to implement the intent of GDC 55 and 56 with regard to instrument lines. This guide applies to all types of nuclear power plants with a primary containment. The NRC issues regulatory guides to describe to the public methods that the staff considers This regulatory guide is being issued in draft form to involve the public in the early stages of the development of a regulatory position in this area. It has not received final staff review or approval and does not