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:
iew procedures are based on the identified SRP acceptance criteria. For deviations from these acceptance criteria, the staff should review the applicant’s evaluation of how the proposed alternatives provide an acceptable method of complying with the relevant NRC requirements identified in Subsection II. 1. To verify that the requirements of GDC 17 are satisfied, the following review steps should be taken: A. The electrical drawings should be examined to ensure that at least two separate circuits from the transmission network to the onsite power distribution system buses are provided (a single switchyard may be common to these paths). For evolutionary light water reactor design applications, 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) fail. The design should also include an alternate power source to non-safety loads, unless it is demonstrated that existing design margins will result in transients for loss of non-safety power events that are no more severe than those associated with the turbine-trip-only event specified in plant designs. See SRP Section 8.3.1 for further details. For passive reactor design applications, such as the AP 1000, the passive safety-related systems 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. If no offsite power is available, it is expected that the non-safety-related diesel generators would be available for important plant functions. However, this non-safety-related ac power is not relied on to maintain core cooling or containment integrity. Therefore, the passive reactor design supports an exemption to the requirements of GDC 17 for two physically independent offsite circuits,