ML20065R534
| ML20065R534 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 10/20/1982 |
| From: | Tucker H DUKE POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8210290250 | |
| Download: ML20065R534 (3) | |
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- DUKE POWER GOMPANY P.O. HOX 33180 CHAMLOTTE, N.C. 28242 IIAL II. TUCKEH TELEPHONE (704) 373-4531 vusemessonov October 20, 1982
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Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission Region iI m
101 Marietta Street, Suite 3100 N
- g, Atlanta, Georgia 30303 g
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Re:
Catawba Nuclear Station g
i Units 1 and 2
- f,3 p/ a Docket Nos. 50-413 and 50-414 a:
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Dear Mr. O'Reilly:
.c-Pursuant to 10 CFR 50.55e, please find attached Significant Deficiency Repett SD 413-414/82-21.
Very truly yours, B.f4y, Hal B. Tucker RWO/php Attachment cc: Director Mr. Robert Guild, Esq.
Office of Inspection & Enforcement At to rney-a t-Law U. S. Nuclear Regulatory Commission 314 Pall Hall Washington, D. C. 20555 Columbia, South Carolina 29201 Mr. P. K. Van Doorn Palmetto Alliance NRC Resident inspector 2135k Devine Street Catawba Nuclear Station Columbia, South Carolina 29205 82102902 3
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CATAWBA NUCLEAR STATION REPORT NUMBER: SD 413-414/82-21 REPORT DATE:
October 20, 1982 FACILITY: Catawba Nuclear Station Units I and 2 10ENTIFICATl0N OF DEFICIENCY:
Potential failure to activate the safeguards system due to possible failure of the switch contacts which shunt the proving lamp.
Deficiency identified August 16, 1982 by Westinghouse (received August 23,1982).
INITIAL REPORT:
On September 20, 1982, A. Ignatonis, NRC Region II, Atlanta, Georgia was notified of the deficiency by W. O. Henry and J. E. Thomas of Duke Power Company, Charlotte, North Carolina.
COMPONENT AND/OR SUPPLIER:
The component which could potentially fall is a test switch contact that is part of the Solid State Protection System manufactured by Westinghouse.
DESCRIPTION OF DEFICIENCY:
During review of a schematic disgram of the Solid State Protection System (SSPS), redrawn for purposes of consolidation, Westinghouse engineers uncovered an undetectable failure which could exist in on-line testing circuits for relays in the system.
Periodic testing of the SSPS Includes actuation of master relays which actuate Safeguards systems. When a preselected master relay is energized, a proving lamp in series with the output (slave) relay coil confirms electrical l
continuity. Operatioa of the relay is prevented by reducing the circuit voltage f rom 120 VAC to 15 VDC during test. Subsequent tests from the safe-1 9uards Test Cabinets energize (120 VAC) each output relay to confirm actuation of the Safeguards device.
In those instances where actuation of the final device cannot be tolerated, a proving lamp in the Safeguards test circuits verifles relay contact movement, field wiring and electrical continuity through the final device. Operation of the master relay by means of the pushbutton test switch removes the shunt from the SSPS proving lamp and allows the 15 VDC to energize it confirming the continuity of the output relay coll.
Upon completion of the master relay and output relay coli continuity tests, 120 VAC circuit voltage is restored. Howeve r, if the switch contacts which shunt the proving lamp should fall to reclose as expected,120 VAC would be applied to the lamp in event the system were called upon to operate. Depend-Ing on the output relay coil impedance and the number of output relays being operated by the master relay contacts, the current through the lamp could cause it to burn open before the output relay (s) energized.
in such an instance associated Safeguards devices in the affected train would not actuate.
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ANALYSIS OF SAFETY IMPLICATIONS:
A test switch contact failure could cause associated safeguard devices in the affected train not to operate.
CORRECTIVE ACTIONS:
A revision to the SSPS test procedure will be made by Westinghouse to i
ensure the relay test circuits in the SSPS operated properly when the system is returned to its normal operating mode. This action will be complete prior to fuel load.
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