Document: NRC Regulatory Guide
Document ID: fc586342-92f7-4c77-ae76-79e3674cf288
Document Type: regulatory_guide
Title: Criteria for Programmable Digital Devices in Safety-Related Systems of  Nuclear Power Plants + HISTORY –HISTORY 02/2023 – DG-1374, Proposed Revision 4 Prior to issuance of DG-1374, RG 1.152 was entitled, “Criteria for Use of Computers in Safety-Systems of Nuclear Power Plants” 06/2010 – DG-1249, Proposed Revision 3 – Revise 12/2004 – DG-1130, Proposed Revision 2 – Revise 05/1995 – DG-1039, Proposed Revision 1 03/1983 – DG-1130, Proposed Revision 2 – Revise (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2301/ML23012A242.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.152
CFR Part: 
CFR Title: 

Content:
logic and data structures. (e) Self-diagnostic functions are verified during periodic functional tests. 1.2.3 Self-diagnostics could be credited, on an application-specific basis, to either reduce or eliminate the channel operability tests, provided criteria 1.2.2(a), 1.2.2(b), 1.2.2(c), 1.2.2(d), and 1.2.2(e) and the following are met: (a) Self-diagnostic features do not adversely impact the reliability of the DI&C safety-related system and its ability to perform safety functions. (b) Self-diagnostics achieve the same acceptance criteria applied to the manual periodic channel operability test. (c) Provisions are in place to confirm the execution of the self-diagnostics during plant operation. The capability to periodically test and calibrate the automatic test DG-1374, Page 9 equipment should also be provided. (d) Administrative control and operation procedures are maintained to periodically verify the performance of self-diagnostics (e.g., periodic checks of event logs, manual verification of setpoints, rebooting of startup self-diagnostics). 1.3 Clause 5.5.4 of IEEE Std 7-4.3.2-2016 provides guidance on the use of priority functions. This clause addresses how command signals received from safety-related I&C PDDs and PDDs that are non-safety-related (NSR) for actuating a safety-related component should be prioritized. This clause does not specify whether the priority function is implemented within the PDD performing the safety-related function or in a separate PDD. If the priority function is used, the licensee or applicant should analyze the implementation to identify the potential introduction of additional hazards due to the increase in interconnectivity between safety-related PDDs and NSR PDDs. (2) Independence 2.1 A propagational failure is one hazard that safety-related systems that use digital communication may be more susceptible to due to the increased potential for errors to be introduced during communications processing and transmission. Sufficient