ML18226A215

Response to Task Interface Agreement 2014-04, Adequacy of the Oconee Nuclear Station Design and Licensing Bases for Degraded Voltage Protection (TAC Nos. MF4622, MF4623, and MF4624; EPID L-2014-LRA-0003)

ML18226A215
Person / Time
Site:	Oconee
Issue date:	01/22/2019
From:	Gregory Suber Plant Licensing Branch II
To:	Gody A Division of Reactor Safety II
Klett A, 415-0489
References
EPID L-2014-LRA-0003, TAC MF4622, TAC MF4623, TAC MF4624
Download: ML18226A215 (21)

Text

/RA/

Code of Federal Regulations,

TSs and TS Bases Changes

Safety Evaluation for AMDs 232, 232, and 231

Amendment Nos. 300, 300, and 300

on the 230-kV switchyard Yellow busTherefore, we find that the licensee's proposed degraded grid protection modification (excluding [TS] changes which will be evaluated in a separate SE) is acceptable [emphasis added].230 kV switchyard yellow bus[emphasis added]

if an ES signal from any unit's Engineered Safeguards Protective System exists [emphasis added]

Also, the undervoltage condition in itself does not result in the separation of the Class 1E distribution system from the offsite grid; an ES (LOCA, MSLB) signal must exist coincidentally before undervoltage protection action occurs [emphasis added]

the staff permitted the use of alarms, procedures and manual actions, in lieu of automatic action [emphasis added]

Due to the complexity of the plant's existing undervoltage protection scheme and the onsite electrical distribution system coupled with the speculation that the quality of the grid servicing the Oconee site may have similar weaknesses to what exists in the Northeast, we conclude that it is not prudent to impose the complete requirements of the BTP[emphasis added]

If an ESF [engineered safeguards] signal is sensed[emphasis added]

and that corrective measures would be taken to assure that timely actions are taken to restore the voltage [emphasis added]