ML17300A755

Special Rept 1-SR-87-012:on 870302,following Cleaning of Contacts,Diesel Generator a Failed to Start in Emergency Mode.Caused by Defective Power Resistor.Root Cause of Failure Data Sheet Initiated & Further Action Will Be Taken

ML17300A755
Person / Time
Site:	Palo Verde
Issue date:	03/30/1987
From:	Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
1-SR-87-012, 1-SR-87-12, 192-00173-JGH-T, 192-173-JGH-T, NUDOCS 8704210109
Download: ML17300A755 (6)

Text

REGULATOR NFORMATION DISTRIBUTION S EH (R IDS)

ACCESSIQN NBR: 8704210109 DOC. DATE: 87/03/30 NOTARIZED: NO DOCKET 0 FAC IL: STN-50-528 Palo Verde Nuclear Stat ioni Uni t 1> Ari zona Pub 1 i 05000528 AUTH. NAME AUTHOR AFF XLIAT ION HAYNES'J. G. Arizona Nuclear Power Prospect (formerly Arizona Public Serv RECIP. NAME REC IP XENT AFFILI*TXQ'A MARTIN> J. B. Region 5i Office of Director

SUBJECT:

Special Rept 1-SR-87-012: on 870302'ollowing cleaning of contactsi diesel generator "A" failed to start in emergency mode. Caused bg defective power resistor. Root cause of failure data sheet initiated 5 further action will be taken.

I DISTRIBUTION CODE: IE01D COPIES RECEIVED'TR ENCL SIZE:

TITLE: General (50 Dkt)-Insp Rept/Notice of Violation Response NOTES: Standardized plant. M. Davisi NRR: 1Cg. 05000528 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 0 PD5 PD 1 1 LICXTRA> E 1 1 DAVIS> M 1 1 INTERNAL: ACRS 2 2 AEQD 1 1 DEDRO 1 1 EN LXEBERMAN 1 NRR ROE. M. L 1 NRR/ADT 1 1 NRR/DOEA DIR 1 1 NRR/DREP/EPB 1 1 NRR/DREP/RPB 2 2 NRR/DRXS DIR 1 1 NR /ILRB 1 QGC/HDS1 1 1 EG FIL 1 1 RES SPEISi T 1 FILE 01 1 1 EXTERNAL: LPDR 1 1 NRC PDR NSIC 1 1 NOTES: 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 25 ENCL 24

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Arizona Nuclear Power Project P.o. BOX 52034 ~ PHof NIX, ARIZONA85072-2034 192-00173-JGH/TRB/TJB March 30, 1987 Mr. John B. Martin, Regional Administrator Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596-5368

Subject:

Palo Verde Nuclear Generating Station Unit 1 Docket No. STN 50-528 (License NPF-41)

Special Report 1-SR-87-012 File: 87-020-404

Dear Mr. Martin:

Attached please find a Special Report 1-SR-87-012 prepared and submitted pursuant to Technical Specifications 4.8.1.1.3 and 6.9.2. This report discusses a valid Diesel Generator failure that occurred on March 2, 1987.

If you have any questions, please contact Tom Bradish, Compliance Supervisor at (602) 932-5300, Ext. 6936.

Very tru y yours, J. G. Haynes Vice President Nuclear Production JGH/TRB/TJB/cld Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

R. P. Zimmerman R. C. Sorenson i E. A. Licitra A. C. Gehr ~i INPO Records Center )r C3 CP Cfl 8704210109 870230 PDR I0IDQCK 05000528 S POR

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PALO VERDE NUCLEAR GENERATING STATION UNIT 1 Valid Diesel Generator Failure on March 2, 1987 Docket No. 50-528 License No. NPF-41 Special Report 1-SR-87-012 This Special Report describes an event involving a valid failure of an Emergency Diesel Generator. The report is provided pursuant to Technical Specifications 4.8.1.1.3 and 6.9.2 and contains the information recommended in Regulatory Position C.3.b of Regulatory Guide 1.108, Revision 1, August 1977.

At approximately 0036 MST on March 2, 1987, with Palo Verde Unit 1 in Mode 4 (HOZ SHUTDOVN), Diesel 'Generator "A" was declared inoperable in order to allow contacts on relays (¹9, ¹10, ¹21) to be burnished. The contacts were being burnished as a prudent measure based on the identification of an oxidation film on the corresponding Diesel Generator relay contacts in Unit

2. Action Statement 3.8.l.l.b was entered as a result of the Diesel Generator inoperability.

At 0245, following the contact cleaning, emergency start signals were sim-ulated through the use of installed jumpers in accordance with the appropriate work order retest instructions. After the jumpers were installed, Diesel Generator "A" started however, speed, voltage and frequency began oscillating.

A second start attempt was made 'with the same results.

Troubleshooting of the Diesel Generator revealed that the cause of the faiiure was a defective power resistor (65PR). The power resistor receives 135 vdc, reduces it to 24 vdc, and provides it to the Governor Amplifier. The Governor Amplifier is part of the main electronic controls for the Governor which regulates the Diesel Generator's engine speed by controlling the fuel control system. Thus, the loss of the power resistor renders the Diesel Generator incapable of starting in the emergency mode. A root cause of failure data sheet has been initiated to determine the cause of the power resistor failure.

Additional corrective action will be taken, results of the root cause determination.

if necessary, based upon the Following the troubleshooting effort, the power resistor was replaced, the appropriate surveillance test was completed, Technical Specification Action Statement 3.8.1.l.b was exited, and the Diesel Generator was returned to service at 0237 on March 3, 1987. The Diesel Generator was unavailable for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the power resistor failure was identified. This is the fourth (4th) failure in the last 100 valid tests. In accordance with the Palo Verde Unit 1 Technical Specification, the current surveillance test interval (once in 31 days) may be continued based on the number of failures (determined on a per Diesel Generator basis).