ML20076G676
| ML20076G676 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/10/1994 |
| From: | J. J. Barton GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C321-94-2150, NUDOCS 9410200138 | |
| Download: ML20076G676 (2) | |
Text
!
c GPU Nuclear Corporation 1
Nuclear
= e; = 388 o
Forked River, New Jersey 08731-0388 609 971-4000 l
Wnter's Direct Dial Number:
l C321-94-2150 October 10, 1994 U. S. Nuclear Regulatory Commission Att: Document Control Desk washington, DC 20555 Gentlemen:
Subject:
Oyster Creek Nuclear Generating Station i
Docket No. 50-219 Facility Operating License No. DPR-16 Response to Request for Additional Information - Technical Specification Change Request No. 219 This letter confirms our discussion via teleconference on September 14, 1994 regarding Technical Specification Change Request (TSCR) No. 219, submitted to NRC on July 8, 1994 (C321-94-2089).
The revised degraded voltage setpoint coupled with interim administrative controls will protect required engineered safety features equipment from the adverse affects of degraded grid voltages. As stated in TSCR No. 219, administrative controls exist to provide adequate protection for 480V and 120V circuits. These administrative controls will remain until appropriate modifications can be completed. Modifications to the 480V system components identified in TSCR No. 21s which require a plant shutdown will be completed by the end of the current 15R refueling outage. Other modifications will be completed in conjunction with the implementation of the requested change to the Technical Specifications.
Additional field testing is ongoing during the 15R outage to verify 120V System voltage drops and current values. Measured voltage and current values will be compared to analysis assumotions. Any modifications to these 120V circuits identified as a result o.! 'Ais reanalysis are planned to be completed no later than the end of the 16R outage consistent with the Long Range Planning Program.
Upon completion of the above noted 480V System modifications and possible 120V System modifications, the revised degraded voltage setpoint will ensure adequate voltage to required engineered safety features eauipment under worst case postulated conditions.
9410200139 941010 t
PDR ADOCK 05000219 P
PDR po\\
1 S U 0 8 5 GPU Nuclear Corporation is a subsidiary of General Pubuc Ut.bes Corporation
\\Q
+
e-
\\
C321-94-2150
)
Page 2 The postulated worst case bus loading for a single onsite power distribution train was conservatively utilized as the basis for calculating the degraded voltage relay setpoint. This assumption is consistent with the design basis of the OCNGS onsite electrical distribution system as described in OC Final Safety Analysis Report (FSAR) Section 8.3.1, and satisfies the intent of 10 CFR 50, Appendix A, General Design Criteria regarding electrical power systems. The basis for the worst case loading on each train assumes that only one of the two power trains is available during the accident scenario.
Therefore, the remaining train must carry all the loads necessary for safe shutdown. The electrical distribution system was mathematically modeled using the DAPPER computer program.
Each train was analyzed separately to determine which was more heavily loaded.
Considering the worst case loading condition on the 4160V bus, downstream voltages were computed by the DAPPER program to determine the acceptability of supplied voltages. This method provides a conservative approach to ensure that all equipment required for safe shutdown is protected at the selected UV relay setpoint.
i If any additional information is required please contact us.
Sincerely, N~
f J. J.
Barton
- Vice President and Director Oyster Creek DJD/ pip c:
Administrator, Region I Oyster Creek NRC Project Manager Sr. Resident Inspector, OC T.
J. Hutler - Mayor of Lacey Township K.
Tosch - Director, NJ Bureau of Nuclear Engineering
-.