Document: NUREG-0800
Document ID: 81256f55-72dd-4777-9472-f373c71c4554
Document Type: srp
Title: AC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550065.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
. Passive light water reactor design applications provide passive safety systems that do not need Class 1E ac electric power, other than that provided by the Class 1E dc batteries and their inverters, to accomplish the plant's safety-related functions for 72 hours. However, as documented in SECY 94-084, SECY-95-132, and Regulatory Guide 1.206 Section C.IV.10, the staff addressed technical issues associated with the RTNSS process in passive plant designs for risk-important, non-safety-related, active systems, such as the ac power system. These systems 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. Passive reactor plant designs should, therefore, include one offsite power source with sufficient capacity and capability from the transmission network to power the safety-related systems and all other auxiliary systems under normal, abnormal, and accident conditions. The offsite power source should be designed to minimize to the extent practical the likelihood of its failure under normal, abnormal, and accident conditions. The design review should therefore address the independence of the offsite power system with regard to the onsite ac power criteria to support those risk-important, non-safety-related, active systems identified through the RTNSS process. 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. Subsequent COL applications could then reference the RTNSS evaluation in the applicable existing certified design control documents to demonstrate their compliance with design requirements for passive design power systems as described in Section C.III.1 of Regulatory Guide 1.206. Further detailed information and guidance on electrical design for passive COL applications are provided in Section C.III.1.8.3.1 of Regulatory Guide