Document: NUREG-0800
Document ID: e47fd320-f3af-41cd-883e-a51e0949005d
Document Type: srp
Title: to verify that the AAC source (or sources) will not adversely affect the
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740424.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.2
CFR Part: 
CFR Title: 

Content:
t=s preferred and Class 1E ac power systems. I. The AAC power system is provided with a fuel supply that is separate from the fuel supply for the onsite EAC power system. A separate day tank, supplied from a common storage tank, is acceptable if the fuel is sampled and analyzed using methods consistent with applicable standards before its transfer to the day tank. J. If the AAC power source and an emergency onsite ac power source are identical, procedures are provided to ensure that active failures of each identical power source will be evaluated for common cause applicability and that corrective action has been taken to reduce subsequent failures. K. The AAC power system is capable of operating during and after an SBO without any support system receiving power from the preferred power supply or the blacked-out unit=s EAC power sources. The capability of the AAC to start on demand depends on the availability of the necessary support systems to fulfill their required function. These support systems may need varying combinations of dc or ac power for varying periods to maintain operational readiness. Information Notice (IN) 97-21 (Ref. 17) discusses two examples of a failure of the AAC to start on demand because of an extended loss of auxiliary electrical power sources. L. The portions of the AAC power system subjected to maintenance activities are/will be tested before returning the AAC power system to service. M. Plant-specific technical guidelines and emergency operating procedures will be implemented (or are in place, as applicable) that identify those actions necessary for placing the AAC power source in service. N. The AAC power system will be inspected, maintained, and tested periodically to demonstrate operability and reliability. The reliability of the AAC power system should meet or exceed 95 percent as determined in accordance with NSAC-108 (Ref. 37) or equivalent methodology. O. Where EDGs are identified as AAC power sources, they should meet the following