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:
Guide 1.206, Section C.III.1 Chapter 8. Detailed review of grounding and lightning protection for the generating station and offsite power system is provided in SRP Section 8.2. Variations in voltage, frequency and waveform (harmonic distortion) in the onsite power system and its components during any mode of plant operation should not degrade the performance of any safety system load below an acceptable level. IEEE Std 308 and other industry standards (Reference 60), and Regulatory Guide 1.206, Section C.I.8.3.1, for COL applications that are not based on certified ALWR designs, provide guidance on system power quality limits and the effects of degraded voltage on instrumentation and protection systems. Regulatory Guide 1.206, Section C.III.1, Chapter 8, provides similar guidance for COL applications that are based on certified ALWR designs. In assessing the adequacy of the electrical ties between the onsite and offsite power systems, and the capability of the preferred power circuits to deliver power to the safety-related buses, both primary and secondary backup protective relaying schemes and their coordination, relay settings, and assigned control power supplies are reviewed. The reviewer should ensure that, in the event of an electrical fault, between the preferred power transformer supply breakers and the safety buses, no single failure will result in reducing the number of preferred power circuits to less than the minimum necessary for safety or prevent the separation of the affected circuit from the respective redundant portion of the onsite power system. In addition, it is verified that no single protective relay or interlock failure will prevent separation of the necessary redundant portions of the onsite power system from the preferred power system upon loss of the latter. Industry standards (References 47, 48, and 56) and, for COL applications that are not based on certified ALWR designs, Regulatory Guide 1.206, Section C.I.8.3.1.2, provide further