ML17347B345

LER 89-009-00:on 890823,boric Acid Transfer Pump Seal Pot Found W/No Visible Level Resulting in No Flow Path to Rcs. Caused by Design of Boric Acid Transfer Pump Double Seals. Review Continuing for Alternate Seal design.W/890922 Ltr

ML17347B345
Person / Time
Site:	Turkey Point
Issue date:	09/22/1989
From:	Goldberg J, Herrin D FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-89-347, LER-89-009-01, LER-89-9-1, NUDOCS 8909270114
Download: ML17347B345 (7)

Text

'CCE~mTED QBUTION DEMON+TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS) e ACCESSION NBR:8909270114 DOC.DATE: 89/09/22 NOTARIZED: NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION HERRIN,D.W. Florida Power & Light Co.

GOLDBERG,J.H. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION k

SUBJECT:

LER 89-009-00:on 890823,boric acid transfer pump seal pot found w/no visible level resulting in no flow path..

W/8 ltr.

DISTRIBUTION CODE- IE22T COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER),

ENCL g SIZE:

Incident'Rpt, etc.

NOTES:

RECIPIENT 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 ACRS MICHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 DEDRO 1 1 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 . NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB NRR/DLPQ/PEB

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1 2

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2 NRR/DLPQ/HFB 10 NRR/DOEA/EAB 11 NUDOCS-ABSTRACT 1,1 1

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1 1 1 RES/DSIR/EIB 1 1 RGN2 FILE 01 1 1 EXTERNAL: EG&G WILLIAMS,S 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOXF TO ALL '%ZC6" RECIPIENTS'IZASE HELP US 'IO REXQCB  %@PTER QMIRCT THE DOCUMENI'GNTBOL DESK RXH Pl-37 (EXT. 20079) m ELIMINAXB YOUR NAME PKH DISTEGBVX'ION.

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P.O. Box14000, Juno Beach, FL 33408-0420 SEPTEMBER 2 2 1989 L-89-347 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 89-09 Date of Event: August 23, 1989 Boric Acid Transfer Pump Seal Pot Found With No Visible Level Resulting in No Flow Path From the Boric Acid Tank to Unit 4 Reactor Coolant S stem The attached Licensee Event Report is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, J. H. Goldberg l Executive Vice President JHG/JRH/cm cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant PDR ADOC~

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Turkey Point Unit 4 02 51 1 OF p 3 TITLE Iel I 1c rans er ump o 1 s1 e eye ng 1n No Flow Path From Boric Acid Tank to Unit 4 Reactor Coolant System EVKNT DATE (5) LER NUMSEA (SI AEPOAT DATE (7) OTHER FACILITIES INVOLVED (SI MONTH DAY YEAR YEAR <cN SSOVSNTIAL tri5 NVMSKR

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4C NVMSSR MONTH DAY YEAR FACILITYNAMES DOCK ET NUM 5 5 R(SI 0 5 0 0 0 823 8 9 8 9 009 0 00 9 22 89 0 5 0 0 0 THIS REPORT IS SUSMITTKD PURSUANT T0 THE REQUIREMENTS OF 10 CFR g: /Chert one or more of the foll~no/ (11 OPKAATINQ MODE (SI

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LICKNSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NVMSEA Oennis W. Herrin, Regulation and Compliance Engineer 305 24 6-6 731 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE OKSCAISED IN THIS REPORT (13)

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On August 23, 1989, at 1715, Unit 4 entered Technical Specification 3.0.1 for 33 minutes when the 4B Boric Acid Transfer Pump (BATP) was declared out of service. At the time of the event, the 4A BATP was out of service to repair a flange leak. At 1715, while making normal rounds, operations personnel discovered that the seal pot, which .pro-,

vides seal cooling water to the 4B BATP, had no visible water level.

Following the discovery, the 4B BATP seal pot was refilled and pump flow was verified . The seal pot level was observed, to remain stable.

This was completed after 33 minutes, and Unit 4 exited Technical Speci-fication 3.0.1. The cause of this event is most likely attributable to the design of the BATP double seals. FPL believes that frequent pump starts and stops may cause axial shaft movement which results in separation of the inner seal faces. When the 4B BATP stopped automatic make-up to the Volume Control Tank at approximately 1700, FPL believes the inner seal faces temporarily "cocked", resulting in a drain of seal water into the pump casing. FPL engineering is continuing to re-view alternate seal designs for the BATPs which will not require quench water to the seal.

NAC Form 355

(%531

NRC.For~ 388A U.S. NUCLEAR REQULATORY COMMISSION I9>]l LICENS )4T REPORT (LER) TEXT CONTI APPROVEO OMS NO. 3) 50M)04 EXPIRES: 8/3)/88 FACILITY NAME I) l OOCKET NUMBER Ill LER NUMSER I8) PAGE (3)

Turkey Point Unit 4 YEAR Q>g EEOUENTIAL NUM \R sgrg ~EVISIOH

'~: NUMSC/I 0 5 0 0 0 2 5 8 9 009 0 0 02 oF 0 3 Deseri tion of the Event On August 23, 1989, at 1715, Unit 4 entered Technical Specification 3.0.1 for 33 minutes when the 4B Boric Acid Transfer Pump (BATP) (EIIS:CA, Component:P) was declared out of service . Unit 4 was operating at 100 percent power with the -4A BATP out of service to repair a leak. At the time of this event, the 4B BATP was aligned to take suction from the C Boric Acid Tank (BAT) and dis-charge to the Unit 4 Charging Pumps, the 3A BATP was aligned to take suction from the A BAT and discharge to the Unit 3 Charging Pumps, and the 3B BATP was aligned to recirculate the B BAT.

At 1715, the 4B BATP was declared out of service when Operations personnel making normal rounds discovered that the seal pot, which contains seal cool-ing water under Nitrogen (N2) pressure, had no visible water level . (These normal rounds are performed on a four hour interval.) Since the 4A BATP had previously been declared out of service, there was no flow path established from the BATs to the Unit 4 Reactor Coolant System (RCS). Technical Speci-fication 3.6.d requires that during power operation, "System piping, inter-locks and valves shall be operable to the extent of establishing one flow path from the boric acid tanks, and one flow path from the refueling water storage tank, to each Reactor Coolant System." Unit 4 entered Technical Specification 3.0.1 which states, in part, "When a Limiting Condition for Operation is not met, except as provided in the associated ACTION requirements, within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> action shall be initiated to place the unit in a MODE in which the specifica-tion does not apply...". Following the discovery, the 4B BATP seal pot was re-filled and pump flow was verified. The seal pot level was observed to remain stable. This was accomplished 33 minutes later at 1748, and Unit 4 exited Technical Specification 3.0.1.

Cause of the Event The cause of this event is most likely attributable to the design of the BATP double seals. FPL believes that frequent pump starts and stops may cause axial shaft movement which results in separation of the inner seal faces. When the 4B BATP stopped automatic make-up to the Volume Control Tank at approximately 1700 on August 23, 1989, FPL believes the inner seal faces temporarily "cocked",

resulting in a drain of seal water into the pump casing.

Upon discovery of the low water level on the 4B BATP seal pot, operations per-sonnel inspected the BATP area. No evidence of seal water leakage from the seal pot drain valve, the 4B BATP outer seal, or from. any seal water system fittings was identified. After adding water to the seal pot an verifying pump flow, the seal pot level was observed to remain stable .

Anal sis of the Event Sufficient shutdown capability for the most severe anticipated cooldown trans-ient (main steam line break), assuming the most reactive control cluster is fully withdrawn, is achieved via the use of boron from the refueling water stor-age tank through the safety in)ection system. This flow path is a normal align-ment required by Technical Specification 3.6.c.4.

NRC FORM 388A (983)

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NPC Fmm 300A (94ll US. NUCLEAR REGULATORY COMMISSION C LICENSEE E ENT REPORT ILER) TEXT CONTI A ION APPROVED OMS NO. 3ISOM104 EXPIRES: 8/3(/88 FACILITY NAME ('II OOCKET NVMSER (3I LER NUMSER (0( PACE (3)

YEAR ~iM$:( SSOI/SHTIAL:y67 RCVISIOH HUMddn HUM00<<

Turkey Point Unit 4 TEXT ///nuun <<wed /0 /Pduiwf. uw 000/and/HRC Ann 30843/ (IT(

o s o o o2 51 89 0 0 900 03 OF 0 3 The BATs and the BATPs provide a souice of concentrated boric acid to be added to the reactor coolant system to offset reactivity changes caused by normal plant operating transients, changes in power levels, and to maintain shutdown conditions . An additional means of providing borated water is from the refuel-ing water storage tank through the charging pumps to the RCS. Although a flow path from the BAT to the Unit 4 Reactor Coolant System (RCS) was not available, the flow path from the refueling water storage tank to the RCS was available throughout the event. The BATPs are required for 10CFR50, Appendix R transients and'or post-LOCA chemistry control. These transients do not require immediate boration, therefore, substantial time is available to realign the Unit 3 BATPs to supply water from the C BAT to the Unit 4 charging pumps'ased on the above, the health and safety of the public were not affected .

Corrective Actions

1) The 4B BATP seal pot drain valve was opened and it was confirmed that the seal pot contained water. Maintenance personnel then added approximately two quarts of water to the 4B BATP seal pot to restore the level .

2) Pump flow from the 4B BATP was verified and the seal pot level was observed to remain stable . A visual inspection of the 4B BATP following restoration of the seal pot level showed no signs of pump outer seal leakage.

3) In LER 250/88-019, FPL made a commitment to evaluate the BATP seal design and initiate a modification to remove the seal pots. Due to the inability to locate an acceptable BATP seal which does not require seal cooling water, this commitment is hereby modified by FPL. FPL is continuing the review of alternate seal designs for the BATPs.

As an interim measure to improve the present BATP seal water system design,

'a plant change/modification (PC/M) will be issued by May 31, 1990. This PC/M will provide improved level indication for the seal pots and will pro-vide a means of adding make-up water without having to remove the seal pot nitrogen pressure indicator from service .

Additional Information The BATPs are manufactured by Goulds, Inc ., Model No. 3196-ST-8 . The, seals are manufactured by Durametallic.

Similar occurrences have been reported in LER 250/88-019, LER 250/88-005, and LER 250/87-017

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