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:
its, operating licenses, and combined licenses must meet the requirements for safety systems in IEEE Std 603-1991 and the correction sheet dated January 30, 1995. In addition, nuclear power plants are currently replacing existing I&C equipment with digital computer-based I&C systems or advanced analog systems. Regulatory Guide 1.47 (Revision 0) does not address the application of digital I&C systems to bypassed and inoperable status indication in nuclear power plants. Therefore, revision of this regulatory guidance is necessary to incorporate the updated IEEE Std 603-1991 on safety systems endorsed by the NRC and to discuss the implications of the use of digital systems on the bypassed and inoperable status indication in nuclear power plants. 2. Objective The objective of this regulatory action is to include appropriate references to IEEE Std 603-1991 and a discussion of digital computer-based I&C systems or advanced analog systems. 3. Alternative Approaches The NRC staff considered the following alternative approaches: • Do not revise Regulatory Guide 1.47. • Update Regulatory Guide 1.47. 3.1 Alternative 1: Do Not Revise Regulatory Guide 1.47 Under this alternative, the NRC would not revise this guidance, and the original version of this regulatory guide would be retained. This alternative is considered the baseline or “no action” alternative and, as such, involves no value/impact considerations. This alternative would leave the regulatory guide outdated with the current regulations in 10 CFR 50.55a(h) and 10 CFR 50.34(f)(2)(v), and would not address the existing new digital I&C technology. 3.2 Alternative 2: Update Regulatory Guide 1.47 Under this alternative, the NRC would update Regulatory Guide 1.47 to reflect the requirements of IEEE Std 603-1991. The updated version would include a discussion of digital computer-based I&C systems and advanced analog systems. The update would retain references to IEEE Std 279-1971, because this IEEE standard remains