Document: NUREG-0800
Document ID: 905c5548-c088-471d-8232-20705a94d137
Document Type: srp
Title: 8.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1136/ML113640121.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.2
CFR Part: 
CFR Title: 

Content:
losing the capability to provide power for the minimum required safety functions.) The onsite electric power supplies, including the batteries, and the onsite electric distribution system, shall have sufficient independence, redundancy, and testability to perform their safety functions assuming a single failure. b. The complete onsite electric power system (Class 1E) must be capable of sustaining a single failure without loss of capability to provide power for the minimum required safety function. Electric power from the transmission network to the onsite electric distribution system shall be supplied by two physically independent circuits (not necessarily on separate rights of way) designed and located so as to minimize to the extent practical the likelihood of their simultaneous failure under operating and postulated accident and environmental conditions. A switchyard common to both circuits is acceptable. c. The offsite system shall be comprised of two physically independent circuits connecting the transmission network (grid) to the onsite distribution system (safety buses). (Separate transmission line towers are required but common switchyard structures are acceptable. No requirement for meeting the single failure criterion and, in the absolute sense, this criterion cannot be met because there is only one power source, the grid.) 8.1-19 Revision 4 - February 2012 GDC 17 Staff Interpretation Each of these circuits shall be designed to be available in sufficient time following a loss of all onsite alternating current power supplies and the other offsite electric power circuit, to assure that specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded. d. Each of the two required offsite power circuits shall be designed to be available in sufficient time to effect safe shutdown in the event of a loss of all onsite power and the loss of the other offsite circuit. (The staff has designated the second