Document: NUREG-0800
Document ID: b351c30f-74b4-4d36-833e-939d23abae4e
Document Type: srp
Title: D-C POWER-SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350494.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.2
CFR Part: 
CFR Title: 

Content:
upplies. To assure this, the control circuits of the bus tie breakers or multi-feeder breakers must preclude automatic transferring of load centers or loads from the designated supply to the redundant counterpart upon loss of the designated supply (Position 4 of Regulatory Guide 1.6). Regarding the interconnections through bus tie breakers, an acceptable design will provide for two tie breakers connected in series and physically separated from each other in accordance with the acceptance criteria for separation of safety-related systems which is discussed below. Further, the interconnection of redundant load centers must be accomplished only manually. b. To assure physical independence, the criteria governing the physical separation of redundant equipment including cables and cable trays, and their implementation as depicted on preliminary (CP stage) or final (OL stage) physical arrangement drawings are reviewed to determine that the' design arrangement satisfies the requirements of IEEE Std 384 and positions of Regulatory Guide 1.75. These guides and standards set forth acceptance criteria for the separation of circuits .and electrical equipment contained in or associated with the safety-related power system. To determine that the independence of the redundant cable installation is consistent with the require- iments set forth in IEEE Std 384 and the positions set forth in Regulatory Guide 1.75, the proposed design criteria governing the separation of safety-related cables and raceways are reviewed includ- I ing such criteria as those for cable derating; raceway filling; cable routing in containment penetration areas, cable spreading rooms, control rooms, and other congested areas; sharing of raceways with nonsafety-related cables or with cables of the same system or other systems; prohibiting cable splices in raceways; spacing of power and control wiring and components associated with safety- related electric systems in control boards, panels, and relay racks; and