ML20214R860
| ML20214R860 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 11/20/1986 |
| From: | Rice P GEORGIA POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-86-377-000 GN-1187, PT21-86-377, PT21-86-377-000, NUDOCS 8612080116 | |
| Download: ML20214R860 (3) | |
Text
Georgia Power Company Post Omce Box 282 Waynesboro. Georgia 30830 Westone 404 554 9961. Ext.0360 3413 404 724-8114 Ext. STS Georgia Pbwer P. D. Rice
"~~~*=-m November 20, 1986 United States Nuclear Regulatory Commission Region II File: X7BG03-M123 Suite 2900 Log:
GN-1187 101 Marietta Street, Northwest Atlanta, Georgia 30323
Reference:
Vogtle Electric Generating Plant-Units 1 and 2; 50-424, 50-425 Diesel Generator Control Relay Panels; Letter GN-1069, dated September 5, 1986 Attention: Mr. J. Nelson Grace In previous correspondence, Georgia Power Company described a potentially reportable condition concerning General Electric Type NGA15AG3 relays used in Transamerica Delaval Diesel Generator Control Panels.
Georgia Power Company has concluded that a reportable condition as defined by Part 10 CFR 50.55(e) and Part 10 CFR 21 does exist.
However, since RTE-Delta has previously notified the - NRC of this condition, Georgia Power Company is submitting this report pursuant to the reporting requirements of Part 10 CFR 50.55(e).
Enclosed is a summary of our evaluation.
This response contains no proprietary information and may be placed in the USNRC Public Document Room.
Yours truly, P. D. Rice REF/PDR/tdm i
xc:
U. S. Nuclear Regulatory Commission Document Control Desk l
Washington, D. C.
20555 H. G. Baker D. R. Altman L. T. Gucwa J. P. O'Reilly P. R. Bemis C. W. Hayes G. F. Head J. A. Bailey G. A. McCarley R. E. Conway
- 0. Batum R. W. McManus i
R. H. Pinson G. Bockhold Sr. Resident (NRC) i C. W. Whitney C. E. Belflower C. C. Garrett (OPC) i B. M. Guthrie J. F. D'Amico J. E. Joiner (TSLA) l D. E. Dutton W. D. Drinkard D. Feig (GANE)
((
R. A. Thomas E. D. Groover NORMS l
8612030116 861120 l
PDR ADOCK 05000424 1/
w ^' -
S PDR
-.y1 "l
EVALUATION OF A P0TENTIALLY REPORTABLE CONDITION DIESEL GENERATOR CONR0L PANEL RELAYS 1
Initial Report: On August 6, 1986, Mr. R.
E.
Folker, Vogtle Project Quality Assurance Engineer, informed Mr.
E.
F.
Christnot of the USNRC-Region II of a potentially reportable condition associated with the failure of General Electric type NGA15AG3 auxiliary relays used in the generator control panel for Class IE emergency diesel generator (EDG).
This condition was initially identified at Vogtle in Operations Deficiency Report ODR T-1-85-1466 and was reported to the NRC by Transamerica Delaval and Delta Controls pursuant to 10CFR21.
In subsequent correspondence to the NRC, Georgia Power Company indicated that a final report on this condition would be submitted by November 21, 1986.
Background Information: The EDG was supplied by Transa'nerica Delaval Inc.,
as a complete package with its control panel assembled by Delta Controls Inc.
The EDG control system consists of an engine control panel and a generator control panel.
There are 14 General Electric (GE) DC auxiliary relays (type NGA15AG3) employed in the generator control panel of each unit.
These relays are continuously rated and have a diode-resistor combination for coil surge suppression.
Ten of these auxiliary relays are used to multiply the generator protective relay output.
These protective relays function during operations such as periodic tests or a loss of offsite power and are bypassed in the event of a loss of coolant accident.
Examples of these protections are EDG circuit breaker tripping, lockout operations, and annunciation initiation at the main control room and at the EDG panel.
The remaining 4 auxiliary relays are used in the generator regulator control circuits to provide control for the generator excitation system.
The generator excitation system provides DC power for the generator field under all loading conditions.
Without this field excitation, the generator will not produce required voltage.
During initial testing of the EDG, one of the auxiliary relays on the Unit l
1 Train B generator control penel (1BCPDG3) burned.
This relay is part of l
the generator regulator control circuit.
The relay was replaced and the panel was then re-energized.
Subsequent checking of the EDG system indicated that the newly installed relay had also burned.
As a result, further inspection of similar relays on the Train B generator control panel was initiated and revealed that two additional auxiliary relays in the Train B generator' control panel showed signs of degradation as a result of resistor overheating.
I Consultation with GE engineers concluded that the resistor overheating and relay degradation and failure was the result of incorrect connection of the coil in a reverse polarity configuration.
Engineering Evaluation:
As required by General Design Criterion 17 and Regulatory Guide 1.9, the EDG must have sufficient capacity and capability to ensure that Class 1E power is supplied to the equipment needed to maintain the plant in a safe condition.
With the identified condition, the EDG could not meet this requirement. Delta Controls Inc., misinterpreted the GE auxiliary j
relay NGA15AG3 wiring diagram which led to reverse polarity connection and l
i
o the burning of the resistor and other electronic components of the relay.
Failure of the auxiliary relays to function as required could result in the loss of the Class 1E EDG and impact the safe operation of the plant.
Quality Assurance Program Evaluation Breakdown: A review of this condition has concluded that a quality assurance program breakdown did not occur.
This condition results from a misinterpretation of GE wiring diagrams.
==
Conclusion:==
Based on the above evaluation, Georgia Power Company has concluded that this condition is reportable per the reporting criteria of Parts 10CFR21 and 10CFR50.55(e).
However, since Delta Controls and Transamerica Delaval Inc., have adequately informed the NRC of the existence of this condition in their respective letters of April 24, 1986 and June 9,1986, Georgia Power Company is reporting this condition per the ' reporting criteria of Part 10CFR50.55(e).
Corrective Action:
A.
The auxiliary relays removed from the EDG generator control panels were tested three times by Delta Controls Inc., and passed the required test.
Delta Controls Inc., stated that the resistors could have been damaged during this series of tests, therefore, the resistors on each relay were replaced.
B.
Following consultation with GE engineering, the subject relays for Unit I were reinstalled and wired correctly through field change requests EFCRB-12287, 12326, 12319, 12327, 12285, 12288, 12289, and 12506 issued on November 27, 1985.
C.
Vendor's drawings of the EDG system for both units were revised, showing the correct wiring of the auxiliary relays.
These drawings were subsequently issued by Bechtel in project elementary diagram format.
Unit 2 drawings were issued August 5, 1986.
D.
Unit 2 auxiliary relays are scheduled to be installed on February 10, 1987, by FEC0 E-281-C, revision 0.
1 l
., _ _ _ - _ _. _