Document: NUREG-0800
Document ID: 9cfc38bf-7808-446e-a43d-4ca9ff55df2a
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740289.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
sure that specified acceptable fuel design limits and design conditions of the reactor coolant pressure boundary are not exceeded. One of these circuits is also required to be designed to be available within a few seconds following a LOCA to assure that core cooling, containment integrity, and other vital safety functions are maintained. 8.3.1-15 Revision 4 - May 2010 GDC 17 requirements for the interface between the onsite ac power system and the offsite power system in evolutionary LWR design applications are documented in SECY-91-078, which states that the design should include at least one offsite circuit to each redundant safety division that is supplied directly from an offsite power source with no intervening non-safety buses, thereby permitting the offsite source to supply power for safety buses in the event the non-safety bus(es) fails. The design should also include an alternate offsite power source to non-safety loads, unless it can be demonstrated that existing design margins will ensure that transients for loss of non- safety power events are no more severe than those associated with the turbine-trip-only event specified in current plant designs. As documented in SECY-94-084 and SECY-95-132, the staff addressed technical issues associated with the RTNSS process in passive plant designs. Risk-important, non-safety-related, active systems in passive LWRs may have a significant role in accident and consequence mitigation by providing defense-in-depth functions to supplement the capability of the safety-related passive systems. Certified passive designs should demonstrate how the RTNSS evaluation process addresses the resolution of design issues, in accordance with SECY-94-084, SECY-95-132, and RG 1.206 Section C.IV.10. Subsequent COL applications could then reference the RTNSS evaluation in the applicable existing certified design control documents (DCDs) to demonstrate compliance with design requirements for passive design power systems as described in