ML18030A369

Forwards, Analysis of Pitting Corrosion Failures in ESW Sys RHR Lube Oil Coolers & RCIC Pump Room Unit Coolers at Susquehanna Steam Electric Station.

ML18030A369
Person / Time
Site:	Susquehanna
Issue date:	11/12/1990
From:	Keiser H PENNSYLVANIA POWER & LIGHT CO.
To:	Butler W Office of Nuclear Reactor Regulation
Shared Package
ML17157A422	List: ML17157A421 ML18030A369
References
PLA-3457, NUDOCS 9011190326
Download: ML18030A369 (3)

Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM

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REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

,ACCESSION NBR:9011190326 DOC.DATE: 90/11/12 NOTARIZED: NO DOCKET FACIL:50-387 Susquehanna Steam Electric Station, Unit 1, Pennsylva 05000387 50-388 Susquehanna Steam Electric Station, Unit 2, Pennsylva 05000388 AUTH. NAME AUTHOR AFFILIATION KEISER,H.W. Pennsylvania Power 6 Light Co.

RECIP.NAME RECIPIENT AFFILIATION R BUTLER,W.R. Project Directorate I-2

SUBJECT:

Forwards, "Analysis, of Pitting Corrosion Failures in ESW Sys RHR Lube Oil Coolers 6 RCIC Pump Room Unit Coolers...." D DISTRIBUTION CODE A001D COPIES RECEIVED:LTR 'NCL SIZE TITLE: OR Submittal: General Distribution NOTES:LPDR 1 cy Transcripts. 05000387 LPDR 1 cy Transcripts. 05000388 RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PDl-2 LA 1 1 PD1-2 PD 1 1 D THADANI,M 2 2 S

NTERNAL: ACRS 6 6 NRR/DET/ECMB 9H 1 1

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NRR/DOEA/OTSB11 NRR/DST/SELB 8D NRR/DST/SRXB 8E REG

'XTERNAL: NRC PDR FILE 01 1

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1 NRR/DST OGC/HDS2 RES/DSIR/EIB NSIC 8E2 NRR/DST/SICB 7E NUDOCS-ABSTRACT 1

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D NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISlS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 25 ENCL 23

~ggg, Pennsylvania Power ii Light Company Two North Ninth Street ~ Allentown, PA18101-1179 ~ 215m0-5151 Harold W. Kelser Senior V/ce President-Nuclear 21 5/770.4194 NOY ~ ~19O.

Director of Nuclear Reactor Regulation Attention: Dr. W.R. Butler, Project Director Project Directorate I-2 Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, D.C. 20555 SUSQUEHANNA STEAM ELECTRIC STATION FINAL REPORT ON RHR MOTOR OIL COOLER FAILURE Docket Nos. 50-387 PLA-3457 FILES R41-2 A22 7D and 50-388

Dear Dr. Butler:

The purpose of this letter is to provide PP&L's final root cause evaluation of the RHR pump motor oil cooler failure which took place on May 28, 1990.

The report concludes that failure of the 2C RHR Pump Motor Oil Cooler was not the result of Microbiologically Influenced Corrosion (MIC) nor was the pitting recent in origin. The cause of the pitting was Under Deposit Corrosion caused by manganese, iron, silt and sediment with some influence by microbiologic activity.

Deterioration took place over a period of years. The rate of corrosion was influenced by such factors as heat, stagnation and velocity but the actual, unanticipated failure was the direct result of the lack of cleaning and inspection which would have provided the data needed to predict the life expectancy of the cooler.

PP&L will ensure that the RHR pump motor oil coolers are replaced prior to the end of useful life. In addition, PP&L will evaluate replacement of the copper coils with materials which are less affected by the corrosion products present in the cooling water.

6 P AGO DOCK 05'OOO3~~

PDC

2 FILE R41-2/A22-7D PLA-3457 Dr. W. R. Butler This revision of the inspection requirements will take place by December 31, 1990 to allow preventative measures to be taken before the 10 year life of the replacement coolers is reached.

In conclusion, we are confident that the actions described herein are conservative and adequate and therefore assure the continued safe operation of the plant.

Very truly yours, H. W. eiser cc: NRC Document-Con. rol Desk (original, with Attachment)

NRC Region I Mr. M.C. Thadani, NRC Project Manager Mr. G. S. Barber, NRC Sr. Resident Inspector