Document: NRC Regulatory Guide
Document ID: fe0fff83-b171-47c6-a3a7-46faf8de3252
Document Type: regulatory_guide
Title: Criteria for The Protection of Safety-Related
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2415/ML24158A041.pdf
Revision Date: 2024-08
Chapter: 
Section ID: RG-1.238
CFR Part: 
CFR Title: 

Content:
e IEEE Standards Board on March 24, 2022. IEEE Std. 741-2022 provides (1) criteria that establish protection requirements for Class 1E power systems and equipment, (2) the purpose of and the means for obtaining protection from electrical and mechanical damage, or from failures that can occur within a time period that is shorter than that required for operator action, and (3) testing and surveillance requirements. The NRC has published several documents on undervoltage relay considerations and the protection of Class 1E power systems, including IN 1995-05, RIS 2011-12, BTP 8-6, IN 2012-03, and BL 2012-01 together with its closure. The capacity, capability, and availability of an offsite power system may be affected by grid maintenance and grid conditions, especially during times of high grid load and high grid stress. The North American Electric Reliability Corporation standard NUC-001-4, “Nuclear Plant Interface Coordination” (Ref. 24), requires coordination between nuclear plant generator operators and transmission entities to ensure safe plant operation and shutdown. NUC-001-4 establishes a protocol for communication with the plant’s transmission system operator, combined with information on the transmission system operator’s capabilities, that can help nuclear power plant operators understand changes in the grid that could affect plant operations. In relation to harmonics and harmonic distortion, IEEE Std. 519, “IEEE Recommended Practice and Requirements for Harmonic Control in Electric Power Systems” (Ref. 25), provides guidance on the design of power systems with nonlinear loads. IEEE Std. 1159, “IEEE Recommended Practice for Monitoring Electric Power Quality” (Ref. 26), and IEEE Std. 1531, “IEEE Guide for the Application and Specification of Harmonic Filters” (Ref. 27), provide additional information on monitoring power quality and on harmonic filters, respectively. The NRC staff reviewed IEEE Stds. 519, 1159, and 1531 and found that these