ML17348A539

Rev 1 to Special Rept:On 900527,discovered That Both nonsafety-related Standby Feedwater Pumps Unavailable for Facility.Caused by Failure of Valve Stem Bushing.Replacement Bushing Mfg on Site

ML17348A539
Person / Time
Site:	Turkey Point
Issue date:	08/29/1990
From:	Harris K FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-287, NUDOCS 9009050322
Download: ML17348A539 (7)

Text

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'<j REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9009050322 DOC.DATE: 90/08/29 NOTARIZED: NO DOCKET r4 FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION HARRIS,K.N. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Rev 1 to special rept:on 900527,facility standby feedwater pumps unavailability.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES'ECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 EDISON,G 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 j AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICB 7E 1 1 1 1 NRR/DST/SRXB SE 1 1 1 1 RES/DSIR/EIB 1 1 1 1 EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 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 FOR DOCUMENTS YOU DON'T NEED! 'ISTS TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

.. Box 029100, Miami, FL, 33102-9100 APL AUG 29 1990 L-90-287 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 3 Docket No. 50-250 Unit 3 Standby Feedwater Pumps Unavailability, Revision 1 to S ecial Re ort Technical S ecification 3.20.1 Action 2.b On May 27, 1990, at 1300 EDT, Florida Power & Light discovered that both non-safety related standby feedwater pumps were unavailable for Turkey Point Unit 3. In accordance with the requirements of Technical Specification (TS) 3.20.1, Standby Feedwater System" and TS 6.9.3.j., a Special Report, FPL letter 90-206 was issued on June 19, 1990, to describe the failure and corrective actions taken.

The attached report is revision 1 to that Special Report. This revision provides additional information on cause, design requirements, and the maintenance history of the valve and bushing that failed.

Should you have any questions please contact us.

Very truly yours,

)J I N$ Harris Vice 'esident Turkey Point Plant Nucl ear KNH/DRP/DPS/ds attachment cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant

</A() -ac PDfi 9OO AOuCK O.OOO"~ O PQI ~~@5 an FPL Group company

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sar-iQ- vs wc'v:~v sv:t" ih-~ra I Cl l~u. DClQ-<4 C,-pagz ~cwQ I I@le Event Descxiption; Qn May 27, 1990, at 1300 EDT, with Unit 3 in Mode 2 (Start-up) zero powe~, Florida Power 6 Light (FPL) discovered that both standby feedwater pumps were unavailable fox Turkey Point Unit 3 using the noxmal path (see discussion of optional paths in section 4) . This condition was discovered while aligning the standby feedwatex pumps to supply feedwater to the steam generators. Valve DWDS-3-012 (a non-safety related commercial grade valve) could not be opened. Since this valve is in the common discharge headex to Unit 3 for the standby feedwatex pumps, both pumps were unavailable to Unit 3. However, both pumps wexe available to Unit 4. The standby feedwater pumps were to be used while 3A steam generator feedwater pump (SGFP) was out of service for maintenance.

Causel Mechanical failure of a valve stem bushing on valve DWDS-3-012 (a non-safety related commercial grade valve) made the valve handwheel inoperable, Examination of the failed bushing indicated the failure was caused by over-stress of the bushing, There was no indication of embrittlement or othex aging factors< manufacturing flaws, or other potential causes for this failure. The ovex-stress condition is believed to be the result of the use of a valve wrench during this operation

{or a previous operation) of the valve.

3 ~ Corrective Actions:

Immediate Corrective Actions Immediate attempts were made to locate a replacement fox the failed bushing. When a replacement could not readily be obtained; a xeplacement bushing was manufactured on-site, approved as acceptable by engineering, and installed, Valve DWDS-3-012 was successfully test opexated and on May 31, 1990, at 1930 EDT, was declared operable.

B. Generic Concern Review An review of plant records was made to locate other installed valves of this type. A sample of other valves of this type would have either been disassembled for inspection of their bushings or would have been test operated, i f plant operat ing conditions permitted, to determine if the bushing failure was a generic concern.

A review of plant records showed this valve to be the only one of this type installed at Turkey Point. A review of the maintenance records indicated no previous failures of this valve or this bushing. A review of the maintenance records of other similar valves used in non-safety related systems indicate that this type of bushing does occasionally fail (one or two on site failures per year) .

C. Maintenance and Surveillances This valve is tested every refueling outage in accordance with procedure O-OSP-074.4, "Standby Steam Generator Feedwater Pumps/Cranking Diesels Test." If any problems are observed during the operation of the valve, action, is initiated to correct the proble'm. The standby feedwater pumps are test operated on a monthly basis in accordance with procedure 0-OSP-074.3, "Standby Steam Generator Feedwater Pumps Availability Test." Additionally, the standby steam generator feedwater pumps and flowpath are used, per procedure, for routine heatup and cooldown of the units.

D. Replacement Parts/Valves Spare bushings as well as material identical to the original bushings, in case they need to be fabricated again, have been ordered. Additionally, if DWDS-3-012 fails, spare valves identical to DWDS-4-012 (in the same position in Unit 4) are available for a total valve replacement.

,E. Operator Training Plant Operations personnel have been notified of the problems associated with DWDS-3-012 and instructed on recommended actions to take when manual valves do not operate freely. This instruction includes precautions on the use of valve wrenches.

Analysis of Event:

A. Standby Feedwater System The Standby Feedwater System is not automatically initiated and requires operator action to be used.

Although the system was installed and is used as a source of feedwater during normal startup, it could provide an additional source of water during accident mitigation for decay heat removal auxiliary feedwater if sources loss of the safety related should occur.

Redundancy The failure of valve DWDS-3-012 does not prevent feedwater flow to the Unit 3 steam generators from the standby feedwater system. The Unit 3 steam generators can be fed from multiple flowpaths to provide redundancy, to assure feedwater to the Unit 3 steam generators in the event main feedwater is unavailable and DWDS-3-012 is shut and can not be opened. These include the following:

1. Auxiliary feedwater pumps,

2. Standby steam generator is not operating, (via feedwater pumps DWDS-4-012 if Unit 4 4 514I 4 515I or 4-516 4-20-510; 3-20-510; and 3-514, 3-515, or 3-516),

3. Turkey Point Unit 2 feedwater pumps via 3-20-510,

4. Turkey Point Unit 4 main feedwater pumps via 4 510 and 3-20-510, and

5. Condensate pumps at lower steam generator pressures (upon RCS cooldown and depressurization)

Design Adequacy A review was conducted of the Standby Feedwater System modification package and the design description in the NRC Safety Evaluation provided with Amendment Number 118 to Facility License Number DPR-31 and Amendment 112 to Facility Operating License Number DPR-41. The review determined that the current Standby Feedwater System is installed as described in the Safety Evaluation.

A B S/G S/G S/G Main Feed Beg Bypass Header 4-5 l 4 Unit 4 4-515 4-516 Normal Feed Unit 4 DWDS-4 -012 P82A 4-510 Steam Aux S/B Feedwater F/W From Feed water Units1 & 2 P82B 3-510 A

S/G S/G S/G Uni.t 3-515 '

3-516 3-514 Normal Feed Unit 3 Sketch I 1

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