Document: NUREG-0800
Document ID: 72cf12c3-a823-4385-bbf4-92e2b543a906
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070498.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
al operation, maintenance, testing, and postulated accidents and (b) be appropriately protected against dynamic effects that may result from equipment failures, including missiles. The ac power system is required to provide power to systems important to safety during normal, abnormal, accident, and postaccident conditions. Meeting these requirements will provide assurance that the ac power system will supply electric power required for operation of systems important to safety even if/when subject to adverse environmental conditions and/or dynamic effects.78 3. Compliance with GDC 5 requires that structures, systems, and components important to safety shall not be shared among nuclear power units, unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units. This criterion requires that component parts of the ac power system 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 required 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 structures, systems, and components of the preferred offsite and onsite power systems. Sharing of onsite ac electric power systems and components is no longer permitted per Regulatory Guide 1.81. 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.79 4. Compliance with GDC 17 requires that onsite and offsite