Document: NUREG-0800
Document ID: 805f7e09-51a2-413b-92af-e23bb9073497
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070493.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8
CFR Part: 
CFR Title: 

Content:
has failed to restore adequate voltages, the Class 1E distribution system should be automatically separated from the offsite power system. Bases and justification must be provided in support of 39 the actual delay chosen. c) The voltage sensors shall be designed to satisfy the following applicable requirements derived from IEEE Std. 279-1971, "Criteria for Protection Systems for Nuclear Power Generating Stations" (Reference 4) and/or IEEE Std 603 (Reference 5) as endorsed by Regulatory Guide 1.153 : 40 1) Class 1E equipment shall be utilized and shall be physically located at and electrically connected to the Class 1E switchgear. 2) An independent scheme shall be provided for each division of the Class 1E power system. 3) The undervoltage protection shall include coincidence logic on a per bus basis to preclude spurious trips of the offsite power source; 4) The voltage sensors shall automatically initiate the disconnection of offsite power sources whenever the voltage set point and time delay limits (cited in item 1.b.2 above) have been exceeded;41 5) Capability for test and calibration during power operation shall be provided. 6) Annunciation must be provided in the control room for any bypasses incorporated in the design. d) The Technical Specifications shall include limiting conditions for operations, surveillance requirements, trip setpoints with minimum and maximum limits, and allowable values for the second-level voltage protection sensors and associated time delay devices. 2. The Class 1E bus load shedding scheme should automatically prevent shedding during sequencing of the emergency loads to the bus. The load shedding feature should, however, be reinstated upon completion of the load sequencing action. The technical specifications must include a test requirement to demonstrate the operability of the automatic bypass and reinstatement features at least once per 18 months during shutdown. In the event an adequate basis can be provided for retaining the load