Document: NUREG-0800
Document ID: 853719df-a6ea-408b-8d43-5956155abc38
Document Type: srp
Title: and 8.3.2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740246.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
on system operator (TSO), independent system operator (ISO), or reliability coordinator/authority (RC/RA). The agreements and protocols should be verified to include preferred operating limits for the offsite power system and preferred actions for recovering from a LOOP event. It should also include the use of transmission load flow analysis and real time contingency analysis (RTCA) software tools (analysis tools) (directly or through the TSO) to assist the NPP in monitoring grid conditions and operating status to determine the operability of offsite power systems under plant technical specifications (TS). The review should verify that the communication protocols are enforced by a formal contract or other means and include notification requirements to inform the NPP when the grid is stressed to the point where a trip of the NPP would result in inadequate post-trip switchyard voltages (less than the design basis voltage) for either actual grid conditions or potential (i.e., anticipatory contingency) grid conditions within any predetermined time limits. Additionally, the reviewer may perform independent calculations using the electronic copy of the model of the onsite distribution system provided by the applicant to ensure that each offsite power circuit has sufficient capacity and capability to provide power to the safety loads. See Section 8.3 for details. The reviewer should also review the description of the analysis tool used by the TSO to determine, in real time, the impact that the loss or unavailability of various transmission system elements will have on the condition of the transmission system to ensure that adequate post-trip voltages are available at the switchyard. The true capability of the offsite source cannot necessarily be verified through direct readings of plant switchyard or safety bus voltages. Recent operating experience (Reference 43) has shown that analyses of the surrounding grid and plant conditions, based on accurate and timely transmission