ML20046B896

LER 93-011-00:on 921219,930209 & 0415,SW Pumps SW-P-41B, SW-P-41B & SW-P-41D Declared Inoperable,Respectively Due High Vibration.Caused by Excessive Abrasive Particles in Ocean Water.Pumps replaced.W/930730 Ltr

ML20046B896
Person / Time
Site:	Seabrook
Issue date:	07/30/1993
From:	Feigenbaum T, Peschel J NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-011, LER-93-11, NYN-93106, NUDOCS 9308060382
Download: ML20046B896 (6)

Text

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y Seab k NH 03874 f

= Telephone (603)474-9521 Energy Service Corporation

( Facsimile (603)474-2987 Ted C. Feigenbaum l

I Senior Vice President and  ;

Chief Nuclear Officer i l NYN-93106 1

l J uly 30,1993 United States Nuclear Regulatory Commission Washington, D.C. '20555 {

i Attention: Document Control Desk  ;

Reference:

Facility Operating License No. NPF-86, Docket No. 50-443

Subject:

Licensee Event Report (LER) 93-01100: " Voluntary LER 93-011, Service ,

Water Pumps SW-P-41B, SW-P-41C and SW-P-41D" i Gentlemen:

Enclosed please find Licensec Event Report (LER) No. 93 011-00 for Seabrook Station. This submittal documents events which occurred on December 19,1992, February ,

9,1993 and April 15,1993. l Should you require further information regarding this matter, please contact Mr. -

James M. Peschel, Regulatory Compliance Manager at (603) 474-9521 extension 377 i

i Very truly yours, l p^ -. i

w. ~

l Ted C. Feigenbau l

TCF:MLM/act f

Enclosures:

NRC Forms 366/366A f f

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f nyI '

_ a member of the Northeast Utilities system / I l

9308060392 930730 PDR ADOCK 05000443 E ,h,'/fu .

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United States Nuclear Regulatory Commission July 30,1993 Attention: Document Control Desk Page two -

i ec: Mr. Thomas T. Martin Regional Administrator l U.S. Nuclear Regulatory Commission l Region I _[

475 Allendale Road King of Prussia, PA 19406  ;

Mr. Albert W. De Agazio, Sr. Project Manager Project Directorate I-4 Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. Noel Dudley NRC Senior Resident Inspector f P.O. Box 1149 ';

Seabrook, NH 03874 ,

i INPO i

Records Center 700 Galleria Parkway ,

Atlanta, GA 30339-5957 l

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NRC fDRM 366 U.S. NUCLEAR RLGULATORY Ct#911SS10 APPROVED BY OMB NO. 3150-0104 (5 97) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH I " E$ "

LICENSEE EVENT REPORT (LER) $Agg"lNu$ EDLgDING g[G BIhlN 5 TE l)

THE 1hf0RMAT10N AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISS]DN, (See reverse f or re::uired nunber of digits / characters for each block) WASHINGTON, DC ?0555-0001, AND TO THE PAPERWORK REDUC 110N PROJE CT (3150-0104), OFF]CE Of MANAGEMENT AND BUDGET, WASHINCTON, DC 20503.

I AClll1Y NAML (1) Scabrook Station DOOR.f i NUMMR (2) PAGE(3) 50-443 1 OF 4 TITtE (4) Voluntary LER for Senice Water Pumps SW-P-418. SW-P-41C and SW-P-41D IVIN1 DAll (5) [ [ R NUMHI R (6) RI P0HI DAll (7) Olltf R I ACillill.S INV0l VID (8) l MONTH DAY YE AR YE AR NUMBE R NUMBER MONTH DAY YEAR 05000

' #" "" UU # "

12 19 92 93 --

11 --

00 07 30 93 0 00 i OPIRAllNG y IHl$ RE P0HI IS MMH H D PURWNI 10 M RIQM Mt NTS M 10 G R D (M one or nm) (H )

MODC (9) 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b) '

POWLR 20.405(a)(1)( t ) 50.35(c)(1) 50.73(a)(2)(v) 73.71(c)

(EVEL (10) 20.405(a)(1)(ii) 50.3b(c)(2) 50.73(a)(2)(vit) X OlHLR 20.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(vitt)(A) (Specify in 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(vtii)(B) A tract b ow 20.405(a)(1)(v) 50.73(a )(2)( iii) 50.13(a)(2)(x) NRC form 366A) l i101NSI[ CONIACI IOR litiS IIR (12)

NAME TELEPHONL NUMBLR (Include Area t' ode)

Mr. James M. Peschel, Regulatory Compliance Manger (603) 474-9521 extension 37/2 COMPtiIF ONI IIN! IOR lADI COMPONINI IAllURE DISCRIBID IN THIS REPORI (13)

CAUSE SYSTEM COMPONENT MANUFACTURER gf3 CAUSE SYSTEM COMPONENT MANUTACTURER ,

B BI P J105 Yes a

SUPPil_MI NI AL RI POR1 IIPI CilD (14) [ XP[ CUD _. MONTH DAY YEAR Yi S SuliMISSIDN  ;

(If yes, corplete EXPECTED SUBMISSION DATE). X N DATE (15) l AH51RACI (Limit to 1400 spaces, i.e., approxinately 15 single-spaced typewritten lines) (16)

This LER is being submitted as a voluntary LER by North Atlantic Energy Corporation (North Atlamic).

At various times during a four month period, three of the four ocean Seniw Water (SW) Pumps were declared inoperable due to high sibration. The pump high vibration conditions occurred m the following order: SW-P-41C, December 19, 1992; j SW P-41D, February 9,1W3, and SW-P-41B, April 15, 1993. Ai! four ocean SW Pumps (SW-P-41A through SW-P-41D) are

Model No. H5056, two stage vertical pumps manufactured by the Johnston Pump / General Valve Co.

There were no adverse safety consequences as a result of these events.

The root cause of the high vibration condition for SW-P-41B, SW-P-41C and SW-P-4]D was due to excessive abrasive particles  ;

present in the ocean water. The abrasive particles produced accelerated wear of the shaft bearing journals. Contributing to i the excessive sibration was the significantly out of balance impellers in each pump.

North Atlantic has replaced / rebuilt all three SW pumps. The replacement! rebuilt pumps were successfully tested and remain in senice to date.

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4 NGC FDRM 35C (5-92)

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l CLC 10RM 36SA U.S. NUCLEAR REGULA10RY COPMISSICJ APPROVED BY OMB HO. 3150-0104 (5-92) EXPIRES 5/31/95 ESTIMATED BURDEN FER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO I LICENSEE EVENT REPORT (LER) THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

i l f ACit IlY NAML (1) IXXXLI NUMBER (2) t ER NUMBER (6) PAGE (3)

YEAR SEQUENilAL REVISION "U" " "

Seabrook Station 50-443 93 2 Of 4 '

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TLXi (11 more space is required, use additiona l copies of NRC form 366A) (17)

HACKGROUND INFORM ATION The Seabrook Station Senice Water (SW) System consists of two, independent and redundant parallel flow trains, each '

l supplying cooling water to a primary component cooling water heat exchanger, a diesel generator jacket water cooler, the  !

secondary component cooling water heat exchangers and the condenser water box priming pump seal water heat exchangers.

l Under normal conditions, flow is supplied by pumps taking suction from a common bay of the SW Pumphouse. If transfer to ,

the Cooling Tower (CT) occurs, senice water is obtained from the CT Basin using the CT Pumps. The SW System utilizes six pumps. Four pumps are in the ocean portion of the system and two pumps are in the CT portion of the system. Each pump ,

is capable of handling 100% of the SW System heat loads following a design basis accident. The SW System Limiting 1 Condition for Operation Action Requirements and Smveillance Requirements are specified in Seabrook Station Technical l Specifications 3/4.7.4 and 3/4.7.5.

I DESCRIPTION OF EVENT Three of the four ocean Service Water (SW) Pumps were declared inoperable due to high vibration at various times between December 1992 to April 1993. The pump failures occurred in the following order: SW-P-41C, December 19,1992; SW-P-41D, February 9,1993, and SW-P-418, April 15,1993. All four ocean SW Pumps (SW-P-41A through SW-P-41D) are Model No.

H5056, two stage vertical pumps manufactured by the Johnston Pump / General Valve Co.

During Seabrook Station's second refueling outage, between September 23, 1992 and October 8,1992, Senice Water Pumps SW-P-41C and SW-P-41D were removed for routine inspection, overhaul, and rebuilt at Seabrook by Station Maintenance personnel. SW-P-41C maintenance consisted of replacing the bowl assembly (including 2 impellers), shafting, bearings and columns with spare parts. SW-P-41D maintenance consisted of reusing the same bowl assembly (including 2 impellers) and replacing the shafting, bearings and columns with spare parts. Post-maintenance testing for both pumps showed normal conditions and operating parameters to be within acceptable limits.

On December 12-13, 1992, a severe ocean storm caused excessive debris and seaweed to enter the Circulating Water (CW) and SW Pumphouses. Senice Water Pumps SW-P-41C and SW-P-41D were operating during the majority of the storm. The unusual amount of debris (scaweed) eventually caused a loss of CW flow to the condensers resulting in a manual reactor trip (LER 92-025-00). l On December 19,1992, SW-P-41C began experiencing high vibration. Vibration signatures indicated that the vibration was excessive (overall vibration was > 1.0 in/sec). The pump was declared inoperable due to high vibration. At the time the pump was declared inoperable, it had accumulated approximately 204 total running hours.

On February 9,1993, SW-P-41D showed signs of higher-than-normal vibration. Vibration signatures indicated that vibration was excessive (spikes up to 1.9 in/sec). As a result, the pump was declared inoperable. At this time, the pump had accumulated approximately 500 total running hours.

On April 15,1993, SW-P-41B showed signs of higher-than normal vibration. Vibration signatures taken during the Technical Specification Operability Surveillance Test were high, although within the limits. Additional vibration analyses were performed, and SW-P-41B was declared inoperable due to high intermittent vibration spikes up to 1 in/sec. At this time, the pump had accumulated approximately 4921 total running hours.

.- .g NRC f 0RM 36fA U.S. MUCLLAR RLGut A10RY CtP911SS]Cd APPROVLD BY OMB NO. 3150-0104 (5-92) EXPlRES 5/31/95 ESTIMATED B'JRDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. 6 FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO LICENSEE EVENT REPORT (LER) THE INF ORMAT10N AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, TEXT CONTINUATION WASHINGTON, DC 20555-000), AND TO THE PAPERWORK ,

REDUCTION PROJECT (3150-0104), OfflCE Of MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

IACitITY NAMI (1) DOCKl1 NuMBIR (?) LIR NUMDfR (6) PAGE (3)

SEQUENTIAL REVISION YEAR NUMBER NUMBER Seabrook Station 50-443 93 00 3 OF 4

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~1LK1 (11 more space is required, use additional copies of NRC f orm 366A) (17)

CORRECTIVE ACTIONS SW-P-41 C l Service Water Pump S%-P-41C was inspected and tested to determine the cause of the vibration. Adjustments were made in an effort to reduce sibration. The vibration could not be reduced and the root cause could not be determined. Therefore, this pump was reinoved from senice and replaced with the original pump which had been removed during OR02. The final assembly consisted of the old column sections, lineshafts, bearings and a new bowl assembly. The replacement pump was successfully tested and remains in service to date. Balance quality of the two impellers currently installed is unknown. The two impullers taken from SW-P-41C pump were returned to the manufacturer who found them significantly out of balance.

The impellers were rebalanced and returned to Seabrook Station.  ;

i SW-P-41 D Service Water Pump SW-P-41D was removed and replaced with a rebuilt pump. The rebuilt pump consisted of new shafts and bearings, as well as the original bow' sembly, columns and impeller.= that were removed from SW-P-41C. The impellers were rebalanced by the manufacturer pri o .o installation. The rebuilt pump was successfully tested and remains in service to i date. The two impellers removed from SW-P-41D were returned to the manufactarer who found them significantly out of balance. The impellers were rebalanced and returned to Seabrook Station.

1 l SW-P-41 B Senice Water Pump SW-P-41B was removed and replaced with a rebuilt pump. The rebuilt pump consisted of a spare bowl assembly and r: balanced impellers. The columns and shafts were also replaced. The replacement pump was successfully tested and remains in senice to date. The two impellers removed from SW-P-41B were returned to the manfacturer who found them signWeantly out of balance. The impellers were rebalanced and returned to Seabrook Station. i l

l ADDtT10NA1, INIORM ATION The SW pump specification states: (1) all pumps shall be tested at the factory to check balance, and (2) operation and 0 performance in accordance with the Hydraulic Institute Standards for Centrifugal, Rotary and Reciprocating Pumps. Johnston UPump has stated that all pump impellers are balanced and documented by company programs and procedures before the

! performance test is implemented. In July 1976, United Engineers & Constructors Inc. conducted a site surveillance at the ,

Johnston Pump facility. The surveillance was to verify all applicable acceptance criteria using a Quality control vendor l Surveillance Check Plan (OCVS) before shipping the pumps to Seabrook. The OCVS did not identify or require verification j of impeller balancing documentation. Johnston Pump has recently been requested to provide pump impeller balancing  !

documeritation for the Seabrook Station SW pumps. Johnston Pur p has reviewed their records and is currently unable to locate this information.

The SW Pumps will be modified by applying a chrome oxide coating to the bearing areas of the shafts and by replacing the existing rubber cutless lineshaft bearings with composite type bearings.

Vibration monitoring will be performed more frcquently following a major storm in order to better detect the onset of acy abnormal conditions. These vibration signatures will be carefully examined and the rotating speed vibration ecmponent trended to detect the onset of degradation.

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MRC FORM 3%A U.S. NUCLi>Jt REGULA1GRY COMMISSION APPROULD DV OMB CD. 3150-0104 (592) EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURL)EN ES11 MATE 10 LICENSEE EVENT REPORT (LER) THE INf0RMA110N AND RECORDS MANAGEMENT BRANCH TEXT CONTINUATION (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHING 10N, DC 20555-0001, AND TO THE PAPERWORK REDUC 110N PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

IACitITY MAM O) 00CK11 NUMBl'R (2) Lt R NUMBt R (6L PACE (3)

YEAR SEQUENTIAL REVI5 ION Seabrook Station 50-443 93 4 OF 4

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1LKt (11 more space is required, use additional copies of NRC f orm 366A) (11)

The SW Pump failure information has been evaluated by North Atlantic Engineering for reportability pursuant to 10CFR21.

Their evaluation of the information found the events not reportable under the provisions of 10CFR21.

To date no significant degradation of the SW Pump 41A has been identified. SW-P-41A is monitored each time it is run and the appropriate maintenance actions will be taken if degradation is noted.

ROOT CAUSE SW. P-41 C .

SW-P-41C was evaluated for the cause of high vibration by Pump & Vibration Consultants, Inc. (PVC). The PVC evaluation concluded that the most probable cause of failure of SW-P-41C was due to excessive abrasive particles present in the water during the December storm. The abrasive particles produced accelerated wear of the shaft bearing journals. This caused the excessive vibration to occur due to the impeller out-of-balance. Since the shaft bearing journals in this type of pump are lubricated by the fluid being pumped, (ocean water in this case) any abrasive material in the water is passed through the bearings resulting in abnormal bearing wear. Additionally, the pump impellers were significantly out-of-balance. This contributed to the pump being removed from senice and declared inoperable.

SW-P-41 D The root cause of failure of SW-P 41D was attributed to excessive abrasive particles present in the ocean water during the December storm. North Atlantic determined the root cause of failure of SW-P-41D to be the same as that of SW-P-41C because of the identical, as-found condition of the pumps and the fact that both pumps were operating during the December storm. SW-P-41C and SW-P-41D had identical wear patterns on the bearing journals. The impellers of SW-P-41D were significantly out-of-balance.

SW- P-41 H The root cause failure for SW-P-41D was attributed to excessive abrasive particles present in the ocean water during the numerous 1492-1993 winter storms. North Atlantic determined the root cause of failure of SW-P-41B to be the same as that of SW-P-41C and SW.P-41D because of the identical, as-found condition of the pumps. SW-P-41B had identictd wear patterns on the bearing journals as SW-P-41C and SW-P-41D. The SW-P-41B impellers were significantly out-of-balance.

PIANT CONDITIONS At the time of each event, the plant was in MODE 1 and operating at 10Ec power.

S AI ETY CONSEOUENCES No adverse safety consequences resulted from the inoperability of the three SW pumps. The SW System remained operable and capable of fulfilling its design basis function during each pump inoperable event. The SW System was maintained operable by transferring heat loads to the CT by existing station procedures. Although the four ocean SW Pumps were declared inoperable, they we.re maintained available for use. If needed these pumps could have been put back into service within approximately ten minutes.

PREVIOUS OCCURRENCES There have been no other previous occurrences / events of this type.

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