ML17345A700

LER 89-009-00:on 890519,design Inadequacy in App R Safe Shutdown Analysis Identified by Util Engineers.Caused by Design Inadequacy.Fire Watches Established for Unit 4 & Will Be Established for Unit 3.W/890519 Ltr

ML17345A700
Person / Time
Site:	Turkey Point
Issue date:	05/19/1989
From:	Herrin D, Woody C FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-89-191, LER-89-009, LER-89-9, NUDOCS 8906020200
Download: ML17345A700 (8)

Text

AC CELEBRATED D1STKBUTION DKMONSTRA,TIO.'i SYSTEM REGULATOR NFORMATION DISTRIBUTION EM (RIDS)

,ACCESSION NBR:8906020200 DOC.DATE: 89/05/19 NOTARIZED: NO DOCKET 8 FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION HERRINPD.W. Florida Power & Light Co.

WOODYPC.O. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 89-009-00:on 890519,10CFR50 App R safe shutdown analysis desi g n inade uac W/8 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

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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 D

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 IRM/DCTS/DAB 1 1 NRR/DEST/ADE 8H 1 1 NRR/DEST/ADS 7E 1 0 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 8D 1 1 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/PEB 10 1 1 NRR/DOEA/EAB 11 1 1 RE RPB 10 2 2 NUDOCS-ABSTRACT 1 1 G~ 02 1 1

1 RES/DSIR/EIB 1 1 RES/DSR/PRAB 1 RGN2 FILE- 01 1 1 R EXTERNAL EGSG WILLIAMSs S 4 4 FORD BLDG HOYPA 1 1 I L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 D NSIC MURPHY,G.A 1 1 S

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P.O. Box14000, Juno Beach, FL 33408-0420 MAY. 1 9 198S L-89-191 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point: Unit 3 Docket No. 50-250 Reportable Event: 89-09 Date of Event: April 21, 1989 10CFR50 A endix R Safe Shutdown Anal sis Desi n Inade ac 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, Actin enior Vice President Nuclear COW/TCG/cm Attachment cc: Stewart D. Ebneter, Regional Administrator, Region /gpss II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant S90$ 020 0 0 890519 PDR ADOCK 05000250PDC S

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NRC Form 255 UA'UCLEARREOULATORY COMMISSION (942)

APPROVEO OMR NO 21500)04 LICENSEE EVENT REPORT (LER) EXPIRE5: 5/2) ISS FACILITY NAME (I) OOCKET NUMSER l2) PA E Turkey Point Unit 3 0 5 0 0 0 2 5 0 1 OFp l5 CFR 50 Appendix R Safe Shutdown Ana1ysis Design Inadequacy EVENT OATS (5) LER NUMSER (SI REPORT OATS (7) OTHER FACILITIES INVOLVEO ISI MONTH OAY YEAR YEAR 54QV5NTIAL oe: treVI5ION MONTH OAY YEAR I ACILITYNAMES COCKET NVMSKRIS)

Glr NUMostl 4%2 NUMesrr Turkey Point Unit 4 0 s 0 o o 0 4 2 1 8 9 0 9 0 0 0 5 1 9 0 5 0 0 0 THIS REPORT IS SUSMITTKO PURSUANT 7 0 THE REQUIREMENTS OF 10 CFR (Ir (Cheep one ot Indre dr the Idlldrrrnd) (11)

OPERATINO MOO E (9) 20.402(II) 20.405(c) 50.72(e) (2)(h) 72.71RII POWER 20.405(el(1)(il SOM(e) I() 50.72le)(2)(rl 72.71(cl LEVEL P P P 20.405(el(1 l(Q) 50.25(c) (2) 50.72(e) (2)(rill oTHER Ispecrrpin Aotrrect

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LICENSEE CONTACT FOR THI5 LER (12)

NAME TELEPHONE NUMSER Dennis M. Herrin, Regu1ation and Compliance AREA COPE 305 2 6- 6749 COMPLETE ONE LINE'FOR EACH COMPONENT FAILURE OESCRISEO IN THIS REPORT (1$ )

CAUSE SYSTEM COMPONENT MANUFAC. MANUFAC IPOIITABL TURER CAUSE SYSTEM COMPONENT TURER

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SUPPLEMENTAL REPORT EXPECTEO ()4)

EXPECTEO MONTH OAY YEAR SU OMISSION YES II/ yet, complete tXPSCTEO $ (idltlSSION OATEI CATE II5I NO AssTRAOT (Umlt to 1400 tpecer, l.A, epproxrmererp Ilrrecn I/nore.rpece rypewrrrren rlnetl l15)

On April 21, 1989, at 1730, with Units 3 and 4 in Mode 5 (cold shut-down), FP&L Engineering identified an Appendix R Safe Shutdown Analy-sis design inadequacy at Turkey Point. The Chemical and Volume Control System charging pumps take suction from either the Volume Control Tank through valve LCV-115C or the Refueling Water Storage Tank through valve LCV-115B An interlock is provided such that LCV-115B if will open- LCV-115C closes. Had a fire occurred in either the Charging Pump Room or Rod Control Equipment Room, LCV-115B may not have opened, LCV-115C -may have closed spuriously and the operating charging pump may have been damaged due to flow starvation. The cause of this event was design inadequacy. The initial Appendix R design review failed to recognize the criticality of timing with regard to alignment of an alternate water source to preclude potential charging pump damage . Fire watches have been established in the Unit 4 Charging Pump Room and Rod Control Equipment Room. Procedure 4-0NOP-016.9 has been issued providing for operator actions upon notification of a fire in these areas. Similar actions will be taken on Unit 3 prior to Mode 4 entry from Mode 5. Long-term corrective action alternatives are under investigation by FP&L Engineering.

NRC Fonx 255 (9.52)

NRC Form 358A UW NUCLKAR RBQULATORY COMM(85(ON (9431 LICENSEE EVENT REPORT ILER) TEXT CONTINUAT ON APPROVBO OMB NO. 3(50M(05 EXPIA88: 8/31/88 PACII ITY NAM8 (1) OOCKBT NUMBBR (1) LBR NUMBBR (8) PAOB (3(

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DESCRIPTION OP THE EVENT On April 21, 1989, with Units 3 and 4 in Mode 5 (cold shutdown), a design inadequacy in the Appendix R Safe Shutdown Analysis was identified by FPGL Engineering.

In accordance with the Appendix R Safe Shutdown Analysis, credit is taken (in each fire area) for only one Chemical and Volume Control System (CVCS) charging pump (EIIS:CB, Component:P) as being avail-able for safe shutdown. Only one charging pump is required to maintain hot standby and achieve cold shutdown in the event of a fire. The charging pumps take suction from either the Volume Control Tank (VCT) through normally open motor-operated level control valve LCV-115C, or from the Refueling Water Storage Tank (RWST) through normally closed air-operated control valve LCV-115B.

An interlock is provided between these valves such that LCV-115B will open if LCV-115C closes.

Since the circuits for valve LCV-115B are routed through the Charging Pump Room and the Rod,Control Equipment Room, it must be assumed that valve LCV-115B will be rendered inoperable due to the adverse effects of a fire in either area. Consequently, should a fire in the Charging Pump Room cause a spurious closure of valve LCV-115C while charging pump "B" is running, or should a fire in the Rod Control Equipment Room cause a spurious closure of valve LCV-115C while charging pumps "A" and "C" are running, the pump(s) will be starved of suction flow from the VCT and RWST since valve LCV-115B may not open. This could potentially cause damage to the operating charging pump(s) due to flow starvation and result in the inability of the applicable charging pump(s) to perform the required safe shutdown function. This scenario applies to either Unit 3 or Unit 4.

The Appendix R Safe Shutdown Analysis takes credit for operator action to mitigate the adverse effects of spurious operation of LCV-115C by aligning an alternate water source to the charging pump(s) prior to sustaining damage. However, the short amount of time available before pump damage could occur was not recognized.

CAUSE OP THE EVEST The cause of this event was design inadequacy in that the initial Appendix R Safe Shutdown Analysis design review failed to recognize the criticality of timing with regard to alignment of an alternate water source to preclude potential charging pump damage upon spurious closure of LCV-115C.

NRC PORM 355A

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NRC Form 3OSA U.S. NUCLEAR REGULATORY COMMISSION (9 93)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO. 3150M(04 EXPIRES: S/31/SS FACILITY NAME lll COCKET NUMSER (ll LER NUMSER (9) PACE (31 yEAR /OII( SEOVENTIAL gRv AOVIOION Turkey Point Unit 3 NVMSSR iiOI( NVMSEII o s o o o 2 5 89 0 9 00 0 3 QF 0 4 TEXT /// more <<>>oe /e norrr/er/ Iree erfd/O'Or>>/NRC Freer JNA'e/ ()7)

ANALYSIS OF THE EVENT The scenario .for thi's event requires an unlikely sequence of events to occur simultaneously:

The VCT outlet valve closes spuriously due to a fire .

The RWST valve logic circuitry is damaged by a fire to the point of malfunction.

The associated charging pump(s) is/are running.

A fire of extreme severity is required to reach the potential for this event to occur. The Turkey Point Final Safety Analysis Report. shows the Charging Pump Rooms as having a low level of "combustible loading".

This "combustible loading", in conjunction with the Fire Protection features provided, should prevent this level of damage .

The major source of combustibles in the Rod Control Equipment Rooms is the exposed cable in, the cable trays. No ignition source, besides the cables, ia available to initiate a fire which could involve the cable trays . This design minimizes the potential for a severe fire ~

Had a fire occurred in either the Charging Pump Room or Rod Control Equipment Room and resulted in a loss of all charging flow during power operation, plant Technical Specification 3.6.d would have been entered and procedure 3/4"ONOP-047.1, "Loss o'f Charging Flow, in Modes 1 through 3," would have been implemented . This procedure requires an operator to determine the cause of the charging pump failure and attempt to reestablish charging flow. If charging flow can not be reestablished, the operator closes the letdown orifice isolat-ion valves and the seal return isolation valve and initiates a shutdown to Mode 3 (hot standby). If charging flow has not been reestablished Coolant after reaching hot standby, provisions are made to ensure that Reactor System inventory lost due to Reactor Coolant Pump number 2 seal leakage is replaced by flow from the Safety In)ection Pumps. A controlled cooldown per procedure 3/4-GOP-305, "Hot Standby to Cold Shutdown," is then initiated utilizing the Safety In)ection Pumps as needed to maintain Pressurizer take level.

If the Safety In]ection Pumps are not operable, time event.

is available to other mitigating actions to prevent escalation of the Based on the above, the health and safety of the public would not have been affected.

CORRECTIVE ACTIONS

1. Fire watches were established for Unit 4 and will be established for Unit 3 in the Charging Pump Room and the Rod Control Equipment Room in accordance with approved Engineering Safety Evaluations prior to entering Mode 4 from Mode 5. Fire watches meet the requirements of procedure O-ADM-016.4, "Fire Watch Patrol," and have means of direct and NRC FORM 3OOA (943)

NRC Potm 3SSA UA. NUCLEAR REQULATORY COMMIS8(ON (943)

LICENSEE E NT REPORT ILER) TEXT CONTINUA N APPROVEO OM8 NO. 3(50-0104 EXP( 8 EE: 8/31/88 FAC1LITY NAME 11) OOCKET NUMEER (2)

LEA NUMBEA (8) PACE l3) yE*R $ 8); SEQUENTIAL 8 ISION Turkey Point Unit i<~~r

3 NVM Sll::.<5 NVMSSA o s o o o 2 5 8 9 009 00 04 OF 0 4 TEXT ///more epece/e eoe/)erL oee d/d//me///RC Fcvm 38SA'e/ l)7) immediate communications to the Control Room.

2. Procedure 4-0NOP-016.9, "Response to a Reported Fire in the Charging Pump Room, Rod Control Equipment Room, Cable Spreading Room or Control Room," was issued on April 27, 1989.

Operator training on this procedure has been performed.

3. Procedure 3-0NOP-016.9 will be issued for Unit 3 prior to entering Mode 4 from Mode 5.

4. A number of long-term corrective actions to resolve the identified Appendix R Safe Shutdown Analysis design inadequacy on Units 3 and 4 are currently being evaluated by FP6L Engineering.

ADDITIONAL INFORMATION Nones No similar Licensee Event Reports have been issued from Turkey Point.

NRC PORM SSSA (983) t'