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:
of the real and/or reactive power support supplied to the grid from the nuclear unit. Plant technical specifications (TS) limiting conditions for operation (LCO) require the offsite power system to be operable. However, since the capability of the offsite power system cannot be tested except when challenged during an actual event, the design bases for the offsite power system can only be assured through analysis of the grid and plant 8.3.1-16 Revision 4 - May 2010 conditions. Plant operators should therefore be aware of: (1) the capability of the offsite power system to supply power, as required by TS, during operation and (2) situations that can result in a LOOP following a trip of the plant. Additional information on the adequacy of grid voltage, grid stability and grid reliability challenges due to deregulation of the utility industry, and the effect of grid events on nuclear power plant (NPP) performance, are provided in References 7, 13, and 38. GDC 17 also requires that the onsite power supplies and the onsite electrical distribution system have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure. Therefore, no single failure will prevent the onsite power system from supplying electric power, thereby permitting safety functions and other vital functions needing electric power to be performed in the event of any single failure in the power system. Guidance on the application of the single-failure criterion is provided in RG 1.53, with applicability as established in 10 CFR 50.55a(h). SRP Section 8.3.1 cites RGs 1.6, 1.9, 1.32, 1.75, 1.153, and 1.155, and NUREG/CR- 0660 as establishing acceptable guidance for meeting the requirements of GDC 17. Meeting the requirements of GDC 17 provides assurance that a reliable electric power supply will be provided for all facility operating modes, including anticipated operational occurrences and design-basis accidents (DBAs) to permit safety functions and other