Document: NRC Regulatory Guide
Document ID: 30181e34-3bc1-46b8-8de9-ef073c34bc13
Document Type: regulatory_guide
Title: Bypassed and Inoperable Status Indication for Nuclear Power Plant Safety Systems + HISTORY - HISTORY 10/2008 – DG-1205 , Proposed Revision 1 (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0821/ML082140114.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.47
CFR Part: 
CFR Title: 

Content:
n shall provide accurate, complete, and timely information pertinent to safety system status.” Clause 5.8.3 of the standard provides the specific guidance on the indication of bypasses, which may be provided by a nonsafety system. The clause states, “If the protective actions of some part of a safety system have been bypassed or deliberately rendered inoperative for any purpose other than an operating bypass, continued indication of this fact for each affected safety group shall be provided in the control room.” IEEE Std 603-1991 defines a safety group as “a given set of interconnected components, modules, and equipment that can accomplish a safety function.” Clause 5.8.3.2 of IEEE Std 603-1991 specifically requires that the indication of bypasses “shall be automatically actuated if the bypass or inoperative condition (a) is expected to occur more frequently than once a year and (b) is expected to occur when the affected system is required to be operable.” Clause 5.8.4 of the standard requires that the location of information displays be “accessible to the operator.” Current designs of safety systems and protective actions are such that certain safety functions of a nuclear power plant may be bypassed or made inoperable during the performance of periodic tests or maintenance. Regulatory Guide 1.118, “Periodic Testing of Electric Power and Protection Systems” (Ref. 4), endorses IEEE Std 338-1987, “Criteria for the Periodic Testing of Nuclear Power Generating DG-1205, Page 4 Station Safety Systems” (Ref. 5), as an acceptable method for the periodic testing of electric power and protection systems. Generally, the plant’s administrative procedures require that the operator give permission before the initiation of any activity that would or could affect a safety system. The decision to grant such permission should be based on knowledge of the operating status of the safety systems, the extent to which the activity will affect those systems,