Document: NUREG-0800
Document ID: 9cfc38bf-7808-446e-a43d-4ca9ff55df2a
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740289.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
feature (ESF) loads in any unit and safely shut down the remaining units in the event of an accident in one unit and a single failure or spurious or false accident signal from another unit and loss of preferred power to all the units. In addition, the physical arrangement of instrumentation and control devices on control room panels and consoles in one unit with respect to the other units is examined to ensure that the design minimizes the coordination needed between unit operators to accomplish sharing of the standby power systems. In the absence of specific criteria in IEEE Std. 308 governing the connection and disconnection of non-Class 1E loads to and from the Class 1E distribution buses, the review of the interconnections will consider isolation devices as defined in IEEE Std. 384 and augmented by RG 1.75 to determine the adequacy of the design. In ensuring that the interconnections of non-Class 1E loads and Class 1E buses will not result in the degradation of the Class 1E system, the isolation device through which standby power is supplied to the non-Class 1E load, including control circuits and connections to the Class 1E bus, should be designed to meet Class 1E criteria. Should the standby power supplies not have been sized to accommodate the added non-Class 1E loads during emergency conditions, the design should provide for the automatic disconnection of those non-Class 1E loads upon the detection of the emergency condition. This action should be accomplished whether or not the load was already connected to the power 8.3.1-30 Revision 4 - May 2010 supply. Further, the design must also prevent the automatic or manual connection of these loads during the transient stabilization period subsequent to this event. The description of the qualification test program (CP stage) and the results of such tests (OL stage) for demonstrating the suitability of the diesel generators as standby power supplies are judged to be acceptable if they satisfy the acceptance