Document: NUREG-0800
Document ID: eb1d19c1-686c-42f5-ba0a-c417c7b12b8e
Document Type: srp
Title: DC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070499.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.2
CFR Part: 
CFR Title: 

Content:
ification, thereby ensuring that an accident in one unit of a multiple-unit facility can be mitigated using an available compliment of mitigative features, including required dc power, irrespective of conditions in the other units and without giving rise to conditions unduly adverse to safety in another unit. SRP Section 8.3.2 cites Regulatory Guides 1.32 and 1.81 to establish acceptable guidance related to the sharing of structures, systems, and components of the onsite dc power system. Regulatory Guide 1.81, Position C.1 recommends that dc systems in multi-unit nuclear power plants should not be shared. 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 onsite power systems.76 DRAFT Rev. 3 - April 1996 8.3.2-10 4. Compliance with GDC 17 requires that onsite and offsite electrical power be provided to facilitate the functioning of structures, systems, and components important to safety. Each electric power system, assuming the other system is not functioning, must provide sufficient capacity and capability to ensure 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 circuits is required to be designed to be available in sufficient time following a loss of all onsite alternating current power supplies