Document: NUREG-0800
Document ID: 98a045ec-37ef-46fc-9eaa-9e695c2d6e53
Document Type: srp
Title: OFFSITE POWER SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350488.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.2
CFR Part: 
CFR Title: 

Content:
he primary reviewer will coordinate this review with the other branch areas of review as stated in subsection I. The primary reviewer obtains and uses such input as required to assure that this review procedure is complete. 1. To assure that the requirements of General Design Criterion 17 are satis- fied, the following review steps should be taken (as applicable for a CP or OL review): (a) The electrical drawings should be examined to assure 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). (b) The routing of transmission lines should be examined on the station layout drawings and verified during the site visit to assure that at least two independent circuits from the offsite grid to the onsite distribution buses are physically separate and independent. No other lines should cross above these two circuits. Attention should be directed towards assuring that no single event such as a tower falling or a line breaking can simultaneously affect both circuits in such a way that neither can be returned to service in time to prevent fuel design limits or design conditions of the reactor coolant pressure boundary from being exceeded. (c) As the switchyard may be common to both offsite circuits, the elec- trical schematics of the switchyard breaker control system, its power supply and the breaker arrangement itself should be examined for the possibility of simultaneous failure of both circuits from single events such as a breaker not operating during fault conditions, spurious relay trip, loss of a control circuit power supply, or a fault in a switchyard bus or transformer. (d) The design is examined to determine that at least one of the two required circuits can, within a few seconds, provide power to safety- related equipment following a loss-of-coolant accident. General Design Criterion 17 does not require these circuits in themselves to be