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
CFR Part: 
CFR Title: 

Content:
formance of the secondary containment air treatment systems will be maintained. d. The potential radiation doses will be substantially below the guidelines of 10 CFR Part 100 and GDC 19. 3. Instrument lines penetrating the primary containment should be provided with an automatically operated isolation valve or one that an operator can manually operate from a remote location (e.g., in the control room or in another appropriate location). The valve should be located in the line outside containment as close to containment as practical. Excess-flow check valves may provide acceptable automatic operation in this application. There should be a high degree of assurance that these valves will perform as follows: a. They will not close accidentally during normal reactor operation. b. They will close or can be readily closed if the integrity of the instrument line outside containment is lost during normal reactor operation or under accident conditions. c. They will reopen or can be readily reopened under the conditions that would prevail when reopening them is appropriate. Power-operated valves should remain “as is” upon loss of power. The status (opened and closed) of all such isolation valves should be indicated in the control room. If a remotely operated valve is provided, sufficient information should be available in the control room or other appropriate location to ensure that the operator can take timely and proper actions. 4. Instrument lines penetrating the primary containment that are connected to instruments that provide input signals to the protection or safety systems and are closed systems both inside and outside of containment (e.g., for containment pressure instrumentation) are acceptable without containment isolation valves if they meet the conditions specified in Section 3.6.2 of American National Standards Institute (ANSI) N271-1976, “Containment Isolation Provisions for Fluid Systems” (Ref. 3). 5. Instrument lines penetrating primary containment