Document: NUREG-0800
Document ID: 65f2433f-2c4a-4580-b173-0c6da7fa4d73
Document Type: srp
Title: Draft Revision 7 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159A996.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
tion 1.6, “D3 Assessment”). Point 3 also addresses manual initiation methods of RTS and ESFAS, if subject to a postulated CCF. The independence requirements of a diverse protection system from the safety protection system (i.e., physical, electrical, and communication separation) are defined in IEEE Std 603-1991. The diverse means could be safety-related and part of a safety division, and would then be subject to meeting divisional independence requirements. The diverse means could also be nonsafety-related in which case the IEEE Std 603-1991 requirement to separate safety-related equipment from that which is not safety-related would still apply and would require independence of the two systems. In either case, the diverse means should be independent of the safety system such that a CCF of the safety system would not affect the diverse system. Point 4 directs the inclusion of a set of displays and manual controls (safety or nonsafety) in the main control room (MCR) that is diverse from any CCF vulnerability identified within the “safety computer system” discussed in Points 1 and 3 above and meets divisional independence requirements as applicable for the specific design implementation. These displays and controls are for manual, system level or divisional level (depending on the design) actuation and control of equipment to BTP 7-19-8 Draft Revision 7 – August 2015 manage the “(plant) critical safety functions” (see Section B.1.2 above). Further, if not subject to the CCF, some of these displays and manual controls from Point 4 may actually be credited as all or part of the diverse means called for under Point 3. The Point 4 phrase “. . . safety computer system identified in Items 1 and 3 above.” refers to the safety-related automated RTS and ESFAS. For digital system modifications to operating plants, retention of existing analog displays and controls in the MCR could satisfy this point (see Section B.1.5, “Manual Initiation of Automatically