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
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CFR Title: 

Content:
achieved given the same input and system properties, including internal and external conditions. PDDs used in safety-related systems should have adequate system integrity such that the safety-related system can operate in a predictable and repeatable manner. Clause 5.5 of IEEE Std 7-4.3.2-2016 provides criteria for achieving system integrity in PDDs for use in safety-related systems. Clause 5.5.1 of IEEE Std 7-4.3.2-2016 refers to Annex D for guidance related to identifying and addressing potential hazards of the system. The NRC staff finds that Annex D of IEEE Std 7-4.3.2-2016 is an acceptable method to identify and control hazards of DI&C devices used in safety-related systems subject to the following clarifications: 1.1.1 The scope of Annex D is limited to DI&C devices. 1.1.2 Annex D provides fault tree analysis and failure modes and effects analysis as the examples of hazards analysis techniques. However, the NRC staff’s endorsement of Annex D does not constitute an endorsement of these techniques, and these techniques are not the only techniques for hazards analysis. 1.1.3 Annex D discusses Annex C in the background section. However, as discussed in Section C1a(1)1.1 of this guide, the NRC staff has not endorsed Annex C of IEEE Std 7-4.3.2-2016 DG-1374, Page 8 because it simply provides useful reference information, rather than specific guidance. 1.2 Clause 5.5.3 of IEEE Std 7-4.3.2-2016 provides criteria that the NRC staff finds acceptable for the use of self-diagnostics for the timely detection of failures. In addition, the criteria for fault detection and self-diagnostics in Clause 5.5.3 should be supplemented with the following: 1.2.1 Typical self-diagnostic methods may include, but are not limited to, monitoring memory and memory reference integrity, using watchdog timer (WDT) or processors, monitoring communication channels, monitoring central processing unit statuses, and checking data integrity. A WDT used to detect lock-up conditions should be