Document: NUREG-0800
Document ID: 97120913-d26f-4324-ab62-22f3f5b73925
Document Type: srp
Title: and 8.3.2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600410.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
oad break switches. For evolutionary light water reactor design applications, as documented in SECY 94-084 for designs such as the CE-ABB System 80+ and the GE ABWR, the design should provide 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 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 (References 33 and 35). These issues are reviewed in detail in SRP Section 8.3.1. 8.2-8 Revision 4 - March 2007 For passive reactor design applications, the passive safety-related systems only require electric power for valves and related instrumentation, which can be supplied from the onsite Class 1E batteries and associated dc and ac distribution systems. The acceptability of this design for the AP 1000 is documented in SECY-05-0227 and FSER NUREG-1793. If no offsite power is available, it is expected that the non-safety-related diesel generators would be available for important plant functions, but this non-safety- related ac power is not relied on to maintain core cooling or containment integrity. Therefore, this passive reactor design supports an exemption to the requirement of GDC 17 for two physically independent offsite circuits, by providing safety-related passive safety systems for core cooling and containment integrity (see also References 33, 34, 35). However, one offsite power source with sufficient capacity and capability from the transmission network must be provided to power the safety-related systems and all other auxiliary systems under normal, abnormal, and accident conditions. The offsite