ML20087J701
| ML20087J701 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/09/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Bishop T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-29038-BSK, DER-83-79, NUDOCS 8403230039 | |
| Download: ML20087J701 (4) | |
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Arizona Public Service Company PO BOX 21666. PHOENIX. ARIZONA 65036 March 9, 1984 ANPP-29038-BSK/TRB T ri0 U. S. Nuclear Regulatory Commission 55 S
Region V Sk-Creekside Oaks Office Park N
3N9 1450 Maris Lane - Suite 210 y**
Walnut Creek, CA 94596-5368
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Attention: Mr. T. W. Bishop, Director Division of Resident Reactor Projects and Engineering Programs
Subject:
Final Report - DER 83-79 A 50.55(e) Reportable Condition Relating to AC Interference l
Spikes On The 125 Volts DC Bus (Diesel Generator) Exceeds
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Specification.
File: 84-019-026; D.4.33.2 Re fere nce : A) Telephone Conversation between T. Young and K. Parrish on November 18, 1983.
B) ANPP-28480, dated December 21, 1983 (Interim Report)
C) ANPP-28753, dated January 30, 1984 (Time Extension)
Dear Sir:
Attached is our final written report of the deficiency referenced above, which has been determined to be Not Reportable under the requirements of 10CFR50.55(e).
Very truly yours,
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(%t E. E. Van Brunt, Jr.
APS Vice President, Nuclear ANPP Project Director EEVB/TRB:db Attcchment ec:
See Page Two 8403230039 840309 PDR ADOCK 05000528 S- '
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l Mr. T. W. Bishop DER 8' -7 9 s
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Richard DeYoung Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 T. G. Woods, Jr.
W. E. Ide D. B. Fasnacht l
A. C. Rogers B. S. Kaplan L. A. Souza J. Vorees J. R. Bynum P. P. Klute A. C. Gehr W. J. Stubblefield W. G. Bingham R. L. Patterson R. W. Welcher H. D. Foster D. R. Hawkinson L. E. Vorderbrueggen G. A. Fiorelli S. R. Frost J. Self 4
D. Canady Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 l
Atlanta, CA 30339 t
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FINAL LEPORT - DER 8 3-79 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNITS 1, 2, 3 I.
Description of Deficiency DERs 83-35 and 83-52 identified safety significant conditions wherein ac spikes in the range of 20-70V-ac range on the 125V-dc bus would af fect the operation of the diesel generator, primarily the speed sensing and starting control circuits. The diesel generator design was based on the allowable 2% (2.1-2.8V-ac) ac-ripple on the 125V-dc bus.
Resolution of DERs 83-35 and 83-52 required modifications to the 125V-dc power supplies to limit ac ripple / spikes to the 2-4V-ac range. However, the new acceptance criteria.of 2-4V-ac ripple / spikes is above the diesel generator original design of 2% (2.1-2.8V-ac) allowable ripple / spikes.
Therefore, Cooper Energy, the diesel generator supplier, was requested to review the new 2-4V-ac ripple / spikes criteria and to evaluate if this revised criteria would in any way impact the safe operation of the diesel generator.
Cooper Energy conducted a factory test on an identical control panel, as supplied to PVNGS, to evaluate the effects of the revised criteria. Cooper Energy letter of January 9,1984 contains Test Procedure S00391-ES0-59-7183-88, and states that the Air Pax speed monitor, without the Bechtel recommendation to install a 1/4 inch Micarta board to insulate the chassis from ground, could tolerate a maximum of 6V-ac ripple / spikes without af fecting the speed pickup circuits.
In addition, Cooper Energy letter of January 9, 1984, file: CES No. 368 states that major components (i.e., exciter, governor) of the control panels, will not be effected by the revised criteria of 2-4V-ac ripple / spikes allowable on the 125V-dc bus.
Cooper Energy has indicated they will review other components in the En.-Tronic panels if deemed necessary.
Bechtel Engineering concurs with Cooper Energy's review that the revised acceptance criteria of 2-4V-ac ripple / spikes will not effect the diesel generator operations. However, to ensure that ac signals are not induced from chassis ground, the Air Pax speed monitor chassis will be modified by adding the 1/4 inch Micarca insulation board.
II.
Analysis of Safety Implications The review of the diesel generator contr61 circuits with regard to the revised criteria of 2-4V-ac ripple / spikes in lieu of the specified diesel generator 2.1-2.8V-ac range indicates no effect on the diesel generator safety-related functions.
In addition, the diesel generator was properly designed to function on the original specified 2.1-2.8V-ac ripple / spikes.
If the 125V-dc revised design requirement of 2-4V-ac ripple / spikes allowable is maintained, the diesel generator control circuits will function properly.
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l Mr. T. W. Bishop ANPP-29038 Page Two Based on the above, this condition is evaluated as not reportable under the requirements of 10CFR50.55(e) or 10CFR21, since if this condition were to remain uncorrected it would not represent' a significant safety condition.
III. Corrective Action A.
Specification Change Notice (SCN) 3535 to Specification 13-MM-018, has been issued to revise the allowable 2-4V-ac ripple / spikes criteria on the 125V-dc bus for the diesel generator.
B.
A Bechtel revision to Cooper Energy drawing G5-262-1009, Sht. 2, will be issued to reflect the Micarta board installation.
I C.
NCR SE-1684 was issued to provide an interim resolution to isolate the Air Pax speed monitor chassis from stray AC ripple / spikes. This was done to support Startup activities.
This NCR will be final dispositioned to implement the addition of Micarta insulation boards.in the Unit I diesel generator control panels.
D.
DCPs 2SM-DG-037 and 3CM-DG-037 have been issued for Unit 2 and 3 modifications, which will be completed based on APS direction.
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