05000416/LER-1993-003

LER 93-003-01:on 930324,SSW C Sys Pump Motor Failed Due to Movement of Motor Stator End Windings During Motor star-ups.SSW C Pump Replaced & Failed Motor Refurbished by GE & Being receipt-inspected.W/930812 Ltr

ML20056D486
Person / Time
Site:	Grand Gulf
Issue date:	08/12/1993
From:	Burke B, Hutchinson C ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GNRO-93-00099, GNRO-93-99, LER-93-003, LER-93-3, NUDOCS 9308160346
Download: ML20056D486 (4)

LER-2093-003,

Event date:
Report date:
4162093003R00 - NRC Website

text

-

U Entergy Operations,Inc.

. =~ ENTERGY e*

P. < ;r n, t.( ? ^>

• _

,n-...

c (E ' . 37 299

..n.

C. R. Hutchinson August 12. 1993 ' ' " "

U.S. Nuclear Regulatory Commission Mail Station Pl-137 Washington, D.C. 20555 Attention: Document Control Desk

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Loss of Single Train Safety System Function LER C3-003-01 CNRO-93/00099 Gentlemen:

Attached is Licensee Event Report (LER) 93-003-01 which is a final report.

Yours truly,

< .ii c ,/

l l _! l_ _ll l

,1

. Lx~ r

• I %/yl ,--/

CRH/BAB attachment cc: Mr. R. H. Bernhard (w/a)

Mr.11. W. Reiser (w/a) l Mr. R. B. McGehee (w/a) l Mr. N. S. Reynolds (w/a)

Mr. H. L. Thomas (w/o)

Mr. Stewart D. Ebneter (w/a)

( Regional Administrator U.S. Nuclear Regulatory Commission l Reaion II 101 Marietta St., N.W., Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor, Project Manager 'w/a)

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13113 Washington, D.C. 20555 ,

I i

I sorn ,

0309160346 930812 I

$DR S

ADOCK 05000416 PDR g;

3

//l

~

< Attachment to GNRO-93/00099

• j@C F ORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO.3160 0104 ,

(se3 EXP1RES 5/31/95 ECTIMATED BURDEN PER RESPONSE TO COkPLY WITH THIS l LICENSEE EVENT REPORT (LER) EME" REGARDiNG#" YREN YSNAS 'T$NE l; INFORMATION AND RECORDS MANAGEMENT DRANCH (MNBB 7714L U S NUCLEAR REGULATORY COMMISSION. WASHINGTON. i DC 20ff$.0001, AND TO THE PAPERWORK REDUCTION PROJECT j (3%D.0104). OFFICE OF MANAGEMENT AND WDGET. {

WASHINGTON. DC 20503 j e ACUT y KAME (1) DOC #11 NuMDER (2) PAGE (3)

Grand Gulf Nuclear Station 05000-416 01 of 03 i TITLE {4)

LOSS of Single Train Safety System Function i EVENT DATE (6) LER NUMBER (6) REPORT NUMBER (7) OTHER F ACILITIES INVOLVED (8) 1 MONTH DAY YEAR YEAR SEQuLNf 6AL RE VI5 ION MONTH CAY YEAR F ACluTf fdME QQCriiNUMBER MBER NWBER N/A 05000  ;

F ACILIT Y NAME DOCriT NUMBER 03 24 93 93 003 01 08 12 93 N/A 05000 ,

OPERATANG THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR $ (Check one or more (11)

MODE '9) 1 20.402(b) 20 405(c) { 50.73(a)(2Hiv) 73.71(b) poi /LIR 20.405(a)(1)(i) 50.36(c)(1) 'X 50.73(a)(2)(v) 73.71(c)

LEVEL (10) 100 20 405(a)(1)(ii) 50 36(c)(2) 50.73(a)(2)(vn) OTHER l 20.405(a)(1)(in) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) g*,*gtf aa8

• l 20 405(a)(1)(iv) 50 73(a)(2)(si) 50.73(a)(2)(viii)(B)  !

20 405(a)(1)(v) 50 73(a)(2)(in) 50 73(a)(2)(x)  !

LICENSEE CONTAC COR THis LER (12)

NAW. TELDHONE NUMBER (inctuos Area Cooe)

Bruce A. Burke / Licensing Specialist 601-437-6333 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THis REPORT (13) i sysTEu c wcneNT Maur ACTuRER cAuse system cOMPoNun MmufACTuRtR R causE ugTgt 4 age t

B Bl MO G080 Y ,

EXPECTED W TH DAY YEAR  ;

SUPPLEMENTAL REPORT EXPECTED (14)

YEs X NO submission I y ye. mpem EEPECTED SUD%S3ON DATE)

DATE (15) ,

ABh rc T steno 14oo .me. s. .m-m.,ev u w.r.mes ,-mn kn .ussi i

a G anc' Gulf Nuclear Station (GGNS) Division ll1 standby service water (SSW C) system pump muor failed on March 5 4 1993. The failure occurred approximately five and one-half hours  ;

into the weekly eight r T ' circulation run. SSW C provides cooling water for the high  !

pressure core spray (: a iumo room coolers and Division 111 standby diesel generator.  ;

j i  !

The cause of the motor failure was investigated by the motor manufacturer. This investigation f determined that the motor stator end windings apparently were moving during motor start-ups.  ;

The end winding movement likely caused a turn-to-turn electrical short which subsequently  :

caused a phase-to-phase short in the motor wind;ngs. The motor had an estimated total run time of twenty-five hundred hours. 7ne suspected cause of the motor failure was initially reported as an apparent phase-to-phase or phase-to-ground short in the motor. The motor was ,

reconditioned by the manufacturer. An NPRDS report was submitted for the failed motor.

All safety related equipmer? operated as designed. Safety and health of the general public  !

were not compromised tv "i event.  !

a

< Attachment to GNRO-93/00099 t/RC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-Ot04 two) EXPIRES E!31/95 ESTMATED EMJRDEN PER RESPONSE TO COMPLY wrrH THIS LICENSEE EVENT REPORT (LER) Eu E REASE"EuEN Em" ATE" E*N TEXT CONTINUATION E"*s'YultES="a'E82*o"^"cNu"$d"w^"AsHi8$*

?E4J"@DC 20503* TlZ"R"l"22"?dk WASHIN3 TON i ACkITV NAML (1) DOCAET NUMBER p) LER NUMBLM (0) PAC.E 0$)

, Grand Gulf Nuclear Station 05000-416 93-003-01 2 OF 03 iu r r m.u . wow co, a wc wm mwm A. REPORTABLE OCCURRENCE Grand Gulf Nuclear Station (GGNS) Diviston ill standby service water (SSW C) system [Bl]

pump motor failed on March 24,1993. SSW C provides cooling water for the high pressure core spray (HPCS) system [BG) pump room coolers and Division 111 standby diesel generator cooling system [LB]. This event is reportable per 10 CFR 50.73(a)(2)(v)(A).

B. INITIAL CONDITIONS The plant was in Operational Condition 1 at approximately 100 percent power with reactor water at approximately 530 degrees F and 1027 psig. The weekly SSW C recirculation run was in progress for approximately five and one-half hours when the failure occurred.

C. DESCRIPTION C: OCCURRENCE While performing the weekly recirculation run of SSW C on March 24,1993, the SSW C pump tripped at 0512 hours0.00593 days <br />0.142 hours <br />8.465608e-4 weeks <br />1.94816e-4 months <br /> due to a pump motor failure. The weekly recirculation run is for corrosion protection and microbiological protection of the open recirculating system SSW C loop; chemical additions are made as part of the recirculation run. This motor failure resulted in declaring SSW C and HPCS inoperable.

D. APPARENT CAUSES The 100 horsepower,1,800 rpm three phase motor smelled of burned wiring /insulEtion upon failure. The motor and pump rotated freely following failure, thereby eliminating a fa' led pump or motor bee as causing the motor failure. It was initially suspected that an electrical sh9rt occurred in the motor, either phase-to-phase or phase-to-ground.

The cause of the motor failure was investigated by the motor manufacturer. This investigation determined that the motor stator end windings apparently were moving during motor start-ups.

The end winding movement likely caused a turn-to-turn electrical short which subsequently caused a phase-to-phase short in he motor windings.

Periodic vibration monitoring ensured that the pump-to-motor coupling was aligned. A vibration test had been performed satisfactorily one week prior to the motor failure.

i

- Attachment to GNRO-93/00099 NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO.315C.0104 'f tsv) EXPIRES SCg6_

. ESTMATED BURDEN PER RESPONSE TO COMPLY WrfH THIS LICENSEE EVENT REPORT (LER) cou$EN" REARE

• iuSE EuN 'T$NE  !

TEXT CONTINUATION ' $7""[s'Tuc^t S="n'e' nut ro7"cEEE ***EETE  !

i

? L " " # M

• W ' %"te"e"s*"?s"'s"uo %a W ASHINGTON, DC 23503 f AGluf Y #AML p) DOCKET NUMbLR (2) LER NUMBER (ti) PAGE (3)

Grand Gulf Nuclear Station 05000-416 93-003-01 3 OF 03 .

TLKT (W mtre spece se requeed use ea$honel copes of AIRC F9m 306A) 0 7)

The existing operating instruction procedure for this pump limits starts to two successive starts ,

from ambient temperature or one start from operating temperature. Subsequent starts may be' I made after thirty minutes of operation or sixty minutes c' being id!e. These controls comply with l vendor recommendations.

The motor had been in service since commercial operation of GGNS. The weekly eight hour I recirculation run was commenced in mid-1990. The motor had an estimated total run time of approximately twenty-five hundred hours.

E. CORRECTIVE ACTION l Immediate corrective actions included performing the action statement specified in GGNS i Technical Specifications 3.5.1,3.7.1.2, and 3.8.1.1. The SSW C pump motor was replaced with

• a spare unit and retested satisfactorily. Operability of SSW C and HPCS was restored at 2245 i hours on March 24,1993. The failed motor was refurbished by the manufacturer (General  ;

Electric) and is being receipt-inspected for return to spare parts inventory. A report was I submitted to the Nuclear Plant Reliability Data System for the motor failure. i F. SAFETY ASSESSMENT  !

l l

SSW water carries heat to the SSW cooling towers, the ultimate heat sink ( wm [BS] at GGNS )

for removal of decay hect generated by the reactor core. Divisions I and ll SSW provide cooling water for a variety of auxiliary systems, three common major toads being the respective train of residual heat removal (RHR) system [BO), standby diesel generator cooling system [LB],

and fuel poo' cooling system [DA). Division til SSW is for HPCS support systems (i.e., Division 111 standby diesel generator cooling system and the HPCS pump room coolers). Divisions I and  !

111 share the same cooling tower, but each division has its own pump. l HPCS is a single train system without any recognized redundancy However, HPCS is backed up by multiple trains of low pressure emergency core cooling systems and the automatic depressurization system. Additionally, high pressure makeup was available from the reactor core isolation cooling (RCIC) system [BN] The out-of-service time was maintained within the limits of GGNS technical specifications, thereby minimizing any safety significance of this event.

Safety and health of the general public were not compromised by this event.  !

G. ADDITIONAL INFORMATION Energy Industry identification System (Ells) codes are identified in the text within brackets [].

.