ML18066A283

LER 98-010-00:on 980721,reactor Manually Tripped.Caused by Failure of Coupling Which Drives Feedwater Pump Main Lube Oil Pump.Main Lube Oil Pump Coupling & Associated Components Replaced & Satisfactorily Tested

ML18066A283
Person / Time
Site:	Palisades
Issue date:	08/18/1998
From:	Engle D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18066A282	List: ML18066A281 ML18066A283
References
LER-98-010, LER-98-10, NUDOCS 9808240283
Download: ML18066A283 (2)

Text

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NRC FORM 366

• U.S. EAR REGULATORY COMMISSION APPROVED MB NO. 3150-0104 EXPIRES 06/30/2001 16*1998) Estimated burden per response to comply with this mandatory information collection request: 50 hrs. Reported lessons learned are incorporated into I the licensing process and fed back to industry. Forward comments LICENSEE EVENT REPORT (LERI regarding burden estimate to the Records Management*Branch (T-6 F33),

U.S. Nuclear Regulatory Commission, Washington, DC 20.555-0001, and (See reverse for required number of to the Paperwork Reduction Project (3150-0104), Office of Management and Budget, Washington, DC 20503. If an information collection does digits/characters for each block) not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

FACILITY NAME 111 DOCKET NUMBER 121 PAGE 131 CONSUMERS ENERGY COMPANY - PALISADES NUCLEAR PLANT 05000255 1 OF 2 TITLE 141 LICENSEE EVENT REPORT 98-010, REACTOR TRIP DUE TO FAILURE OF THE MAIN FEEDWATER PUMP EVE ~T nt .TE 151 I S:R 0.11 ***nr-n 11'::1 REPORT n.1TE 171 nTUS:R Clt.f"ll ITIS:C:: 111vn1 VFn /RI MONTH OAY YEAR YEAR SEQUENTIAL NUMBER IREVISION NUMBER MONTH DAY YEAR FACILITY NAME DOCKET NUMBER 05000 FACILITY NAME DOCKET NUMBER 07 21 98 98 --* 010 -- 0 08 18 1998 05000 I THIS RFPORT IS C::llR.MITTl'n PllRC::llAl\lT TO THE nr:n1 *ft .. llll=lllTC:: nc 1n rcR 6* trh.,,.i.- nn* nr morel 1111

, .OPERATING*

MODE (9)

I 20.2201 (b) 20.2203(a)(1) 20.2203(a)(2)(v) 20.2203(a)(3)(i)

50. 73(a)(2)(i)

50. 73(a)(2)(ii) 50.73(a)(2)(viii)

50. 73(a)(2)(x) 0 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50. 73(a)(2)(iii) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) x 50. 73(a)(2)(iv) OTHER

- NAME Dale Engle, Licensing Engineer 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 50.36(c)(1) 50.36(c)(2)

. I ll"S:l\ICCC r.nNT .ar.T cnD THIC:: I Cl 11 71

50. 73(a)(2)(v)

50. 73(a)(2)(vii)

TELEPHONE NUMBER !Include Area Code)

(616) 764-2848 Specify in Abstract below or in NRC Form 366A l"nlVIDI FTF n111i: 111111= i:nR S:Al"H :A11 11ci: ni:c l"RIDi:n IN ru1c:: -~- n* 1 1 ::II REPORTABLE . REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO EPIX TO EPIX B SJ CPLG W318 y SUPPLEMENTAL REPORT h.-c .. 1tu1141 MONTH DAY YEAR EXPECTED 1~

(If yes, complete EXPECTED SUBMISSION DATE). Ix 'NO.

SUBMISSION DATE (15)

ABSTRACT (Limit to 1400 spaces, i.e., approximately 1 5 single-spaced typewritten lines) (16).

On July 21, 1998, at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, with the Plant operating at 99.6% power; the reactor was manually tripped due to a partial loss of main feedwater [SJ]. At the time of the reactor [RCT] trip one of the two main feedwater pumps [P] had tripped.

The Control Room received an oil system trouble alarm [AA] on the "A" main feedwater pump turbine driver, followed immediately by a trip of the main feedwater pump. In response to the trip of the main feedwater pump, the reactor was manually tripped in accordance with operating procedures. When the steam generator low level set point was reached, the auxiliary feedwater system [BA] actuated as expected.

The main feedwater pump trip was caused by failure of the coupling which drives the feedwater pump's main lube oil pump, resulting in a feedw~ter pump trip on low lubricating oil pressure.

The main lube oil pump coupling [CPLG] and associated components were replaced and satisfactorily tested in conjunction with returning the plant to operation.

9808240283 980818 PDR ADOCK 05000255 s PDR NRC FORM 366 (6-1 998}

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\) NRC FORM 366a U.S. NUCLEAR REGULATORY COMMISSION 6/98 LICENSEE EVENT REPORT (LER) g TEXT CONTINUATION FACILITY NAME 11 l DOCKET12l LER NUMBER f6l CONSUMERS ENERGY COMPANY YEAR I SEQUENTIAL NUMBER REVISION NUMBER PALISADES NUCLEAR PLANT 05000255 2 98 010 00 TEXT (If more space 1s required, use add111onal copies of NRC Form 366A) (17)

EVENT DESCRIPTION On July 21, 1998, at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, with the Plant operating at 99.6% power, the reactor was manually tripped due to a partial loss of main feedwater. Prior to the reactor trip, both main feedwater pumps were operating in automatic mode providing feedwater to the steam generators. The Control Room received an oil system trouble alarm on the "A" main feedwater pump turbine driver, followed immediately by a trip of the main feedwater pump.

In response to the trip of the main feedwater pump, the reactor was manually tripped in accordance with operating procedures. Subsequent to the reactor trip, the steam generator low level set point was reached, resulting in an actuation of the auxiliary feedwater system.

All safety systems functioned as designed. This event resulted in both the manual

• actuation of the reactor protection system [JD] and the automatic actuation of the auxiliary feedwater system.and is therefore reportable to the NRC in accordance with 10CFR50.73(a)(2)(iv) as an event that resulted in actuation of engineered safety features.

ANALYSIS AND CAUSE OF THE EVENT The "A" main feedwater pump turbine driver was subsequently inspected to determine the cause for the pump trip. Upon disassembly and inspection, it was determined that the main feedwater pump trip was caused by failure of the coupling which drives the feedwater*

pump's main lube oil pump, resulting in a feedwater pump trip on low lubricating oil pressure. The coupling was noted to have exceeded its service life, having worn excessively at its mating surfaces, ultimately to the extent that it could no longer transmit torque from.the drive shaft to the oil pump shaft. Contributing to coupling wear were worn drive shaft bearings, which allowed excess shaft play, and the coupling itself, which was not appropriately centered between the shafts.

Past periodic inspections of the main feedwater pump turbine driver internal components have been performed without detailed written instructions, resulting in the missed opportunity to identify and replace these components prior to failure.

SAFETY SIGNIFICANCE This event had no safety significance. Applicable safety systems functioned as expected.

The plant was stabilized and maintained in hot shutdown until the next day when it was returned to service.

CORRECTIVE ACTIONS The main lube oil pump coupling and associated components were replaced and satisfactorily tested in conjunction with returning the plant to operation.

• Detailed work instructions are being developed and implemented to support future periodic inspection activities on the main feedwater pump turbine driver internal components.