Document: NUREG-0800
Document ID: 81256f55-72dd-4777-9472-f373c71c4554
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550065.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
emaining units. Accordingly, component parts of the ac power system should not be shared among units without sufficient justification, thereby ensuring that an accident in one unit of a multiple- unit facility can be mitigated using an available compliment of mitigative features, including necessary ac power, irrespective of conditions in the other units and without giving rise to conditions unduly adverse to safety in another unit. SRP Section 8.3.1 cites Regulatory Guides 1.32 and 1.81 to establish acceptable guidance related to the sharing of SSCs of the preferred offsite and onsite power systems. [Sharing of onsite ac electric power systems and components is no longer recommended per Regulatory Guide 1.81. (For new plants, sharing of diesel generators between units is not recommended.)] Meeting the requirements of GDC 5 provides assurance that an accident within any one unit of a multiple-unit plant may be mitigated irrespective of conditions in other units without affecting the overall operability of the offsite and onsite power systems. 4. Compliance with GDC 17 requires that onsite and offsite electrical power be provided to facilitate the functioning of SSCs important to safety. Each electric power system, assuming the other system is not functioning, must provide sufficient capacity and capability to assure that specified acceptable fuel design limits and the design conditions of the reactor coolant pressure boundary are not exceeded as a result of anticipated operational occurrences and that the core is cooled and containment integrity and other vital functions are maintained in the event of postulated accidents. GDC 17 further requires that electric power from the transmission network to the onsite electric distribution system be supplied by two physically independent circuits designed and located so as to minimize the likelihood of their simultaneous failure under operating, postulated accident, and postulated environmental conditions. Each of these