ML17221A658

LER 88-001-00:on 880201,safety Injection Tank 2B2 Declared Out of Svc & Relief Valve on Fill & Drain Line to Safety Injection Tank 2A2 Lifted & Failed to Reseat.Caused by Failure of Valves.Work Repair Orders issued.W/880301 Ltr

ML17221A658
Person / Time
Site:	Saint Lucie
Issue date:	03/01/1988
From:	Conway W, Powell J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
L-88-105, LER-88-001-02, LER-88-1-2, NUDOCS 8803090335
Download: ML17221A658 (6)

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I AC CELZMYED DI BUTION DEMONSTRA,s ON SYSTEM I

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8803090335 DOC.DATE: 88/03/01 NOTARIZED: NO DOCKET FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power & Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION POWELL,J.M. Florida Power & Light Co.

CONWAY,W.F. Florida Power & Light Co.

RECIPIENT AFFILIATION 'ECIP.NAME

SUBJECT:

LER 88-001-00:on 880201,safety injection tanks out of svc due to unrelated valve reseatzng problems. R W/8 I

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL L SIZE:

TITLE: 50.73 Licensee Event Report (LER), 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 TOURIGNY,E 1 1 h INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 AEOD/DOA 1 1 AEOD/DSP/NAS 1 1 AEOD/DS P/ROAB 2 2 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADS7E4 1 0 NRR/DEST/CEB8H7 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB7A 1 1 NRR/DEST/MEB9H3 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSBSD1 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 1 NRR/DLPQ/HFB10D 1 1 NRR/DLPQ/QAB10A 1 1 NRR/DOEA/EAB11E 1 1 NRR/DREP/RAB10A 1 1 NRR/DREP/RPB10A 2 2 COG FI~I NRRQD~IS/Q B9A1 RES/DE/EIB 02 1

1 1

1 1

1 NRR/PMAS/ILRB12 RES TELFORD,J RES/DRPS DIR 1

1 1

1 1

1 RGN2 FILE 01 1 1 EXTERNAL EG&G GROH i M 5 5 FORD BLDG HOY,A 1 1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS,J 1 1 NSIC MAYS,G 1 1 8

A TOTAL NUMBER OF COPIES REQUIRED: LTTR 46 ENCL 45

NAC Form 355 V.S. NUCLEAR REGULATORY COMMISSION (94)3)

APPROVED OMS NO. 3150-0101 LICENSEE EVENT REPORT (LER) EXPIRES; 5/31/SS FACILITYNAME (I) POCKET NUMbER (2) PAGE 3 St. Lucie Unit 2 0 5 0 0 0 1 OF T'E(I 2A2 AND 2B2 SAFETY INJECTION TANKS SIMULTANEOUSLY OUT OF SERVICE DUE TO UNRELATED VALVE RESEATING PROBLEMS EVKNT DATK (51 LER NVMSER (SI REPORT DATE (7) OTHER FACILITIES INVOLVED ( ~ )

MONTH OAY YEAR YEAR SKGUKNTIAL .a@1 RSY>S>ON MONTH OAY YEAR FACILITYNAMES DOCKET NUMSERISI NUMSKA NUMSSA 0 5 0 0 0 0 201 88 8 0 0 1 0 0 3 01 8,8 0 5 0 0 0 THIS REPORT IS SUSMITTEO PURSUANT T 0 THE RKOVIRKMENTS OF 10 CFR (I: ICnecs one or more oi tne Ioiiovnnei (11 OtERATING MODE (5) 20.C02(i) 20AOS(cl 50.73(s) (2) Orl 73.71(II)

~ OycE A 20AOS(sl(ll(ll SOW(cl(ll 50.73(s) (2)(v) 73.71(cl LEUKL (10) 1 0 0 20.605 4) llI I II) 50.35(sH2) 50.73( ~ ) (2)(vill OTHER ISpeciryin Asttrsct Oeiorr endin test. HAC Form 20.COS(s)II)l(5) 50.73( ~ )(1)lll 50,73(s l(2)(rill)IA) 366AI 20A054)ll)liv) 50.73(sl(1)I4) 50,73( ~ ) (21(vINII 5)

".. '. ", 'nh ~xolg)P++' 20.6054) llllvl 50.734) (1 I(ISI 50.73( ~ l(2)(sl LICENSEE CONTACT FOR THIS LER (11)

NAME TELEPHONE NUMBER Powell, Shift Technical Advisor J. M.

305465-3550 AREA CODE COMPLETE ONE LINE FOR EACH COMtONENT FAILURE OESCRISED IN THIS AEPOAT (13)

CAUSE SYSTEM COMPONENT MANUFAC. EPORTASLE MANUFAC EPORTASLE TIIAER TO NPADS CAUSE SYSTKM COMPONENT TUAER TO NPADS X B P R V T 0 2 0 Yes c'RNPWI(

XBPVTV C 710 Yes v .

SVttLEMENTAL REtORT EXtECTED (lsl MONT>> DAY YEAR EXPECTED SU 5 MlSS10 N IH yet. comptete EXPECTED SVSMISSIOH DATEI DATE II5I YES X NO AssTRAcT ILimit to (coo specee. I e., epommmstery AINen tincre.apace type>sr>INn oner) 11 ~I On February 1 at 1008, while operating at 100% power, the St. Lucie Unit 2 2B2 Safety Injection Tank (SIT) was declared out of service due to the failure of a nitrogen vent valve to reseat. The valve had been opened to relieve excess nitrogen pressure while the tank was being filled. While waiting for nitrogen gas to be directed to the 2B2 tank, licensed control room operators began filling the 2A2 SIT. A relief valve on the and failed to reseat.

fill and drain line to the 2A2 SIT lifted Although the relief valve was immediately isolated, the level in the tank dropped sufficiently (1.5%) to allow nitrogen pressure to drop below the limits of Technical Specification 3.5.l.d. The 2A2 SIT was declared out of service at 1017 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.869685e-4 months <br />, and the plant entered action statement 3.0.3.

The 2A2 SIT was returned to service 8 minutes later at 1020 hours0.0118 days <br />0.283 hours <br />0.00169 weeks <br />3.8811e-4 months <br />, and the unit exited the 3.0.3 action statement. At 1028 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91154e-4 months <br />, the 2B2 SIT was returned to service, and all action statements were exited.

A plant work order has been issued for the nitrogen vent valve on the 2B2 SIT; until the work can be performed, a tag has been placed on the valve handswitch on the Control Room control board. A plant work order has also been issued on the 2A2 SIT the valve will remain isolated.

fill Isnd drain line relief valve. Until the work can be performed, This report is being submitted for informational purposes only.

8803090335 880302 PDR ADOCh. 05000389 (9 83I D( D

1 NRC form 3SSA U.S. NUCLEAR REOULATORY COMMISSION

/943 I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO, 3I 50&104 EXPIRES: B/31/BB FACILITY NAME Ie> OOCKET NUMBER ISI LER NUMBER IS) PACE I3)

SSOUSNTIAL 4evrsICN YEAR Id($ NUMeeR @j NUMSSR St. Lucie Unit 2 o 5 o o o 3 8 9 8 8 0 0 100 02 OF 0 4 TEXT /// more /pere /e /er/Ir/red, Ir/O odd/I/one/ HRC Fomr 3BEA'F/ I Ill DESCRIPTION OP EVENT On February 1, 1988, St. Lucie Unit Two was in Mode One (steady state operations, 100%

Injection power). Operations personnel were preparing to Tanks (SZT) (EIIS:BP).

fill the 2B2 and 2A2 Safety At 1003 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.816415e-4 months <br />, the licensed reactor control operator began to SIT. Zn accordance with procedural guidelines, as nitrogen pressure within fill the 2B2 the tank increased due to the increasing water level in the tank, a nitrogen vent valve was cycled to relieve pressure. After cycling the valve, noticed that the pressure in the SIT was still decreasing, even though the it was vent valve was indicating closed. Several attempts to close the valve were made using the hand switch in the Control Room before the gas pressure in the SZT stabilized, indicating the vent valve had closed. At that time, nitrogen pressure in the 2B2 SIT was approximately 465 psig, which was below the limits defined by St. Lucie Unit Two Technical Specification 3.5.1., and the 2B2 SZT was declared out of service at 1008 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.83544e-4 months <br />.

Operations personnel decided to continue filling the 2B2 SZT to the normal operating level of 85%, and then go on to repressurize the filled tank. When the 2B2 SIT was filled, non-licensed utility operators were told to begin lining up the nitrogen supply to the tank.

While the nitrogen system line up was in progress, the licensed Control Room operators began filling the 2A2 SIT to the normal operating level of 85%.

When the 2A High Pressure Safety Injection (HPSI) (EIZSEBQ) pump was started, level in the 2A2 SIT began to drop. A relief valve on the to the SIT had lifted and failed to reseat. The Assistant Nuclear Plant Supervisor fill and drain line supervising the operation immediately ordered that the relief valve be isolated by closing an upstream test return valve. This was done, but not before the level in the 2A2 SZT had dropped approximately 1.5%. The corresponding nitrogen cover-pressure had also dropped to 562 psig, which was below the 570 psig limit required by Unit Two Technical Specification 3.5.l.d. The 2A2 SIT was declared out of service at 1017 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.869685e-4 months <br />, and the plant entered Limiting Condition for Operation 3.0.3.

Operations personnel continued filling the 2A2 SZT, and at 1020 hours0.0118 days <br />0.283 hours <br />0.00169 weeks <br />3.8811e-4 months <br />, the 2A2 level and pressure were restored to the limits specified in T.S. 3.5.1.

At 1028 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91154e-4 months <br />, when nitrogen pressure was restored to the normal operating pressure of 615 psig, all action statements were exited.

NRC FORM SeeA I94LTI

NRC Form 3BSA U.S. NUCLEAR REGULATORY (943) COMMISSIO'PPROVED LICENSEE EVENT REPORT (LER) TEXT CONTINUATION OMB NO. 3(SOW(04 EXPIRES: S/31/BS FACILITY NAME (I I DOCKET NUMBER l3) LER NUMBER (S) PACE (3)

YEAR SEOVENTrAL REYISloN St. Lucie Unit 2 NVMSOR rrVMBER o s o o o 8 8 0 0 1 00 03 OF 0 4 TEXT /// rrroro <<roco /o rtu/))o L uoo oddro'orro/ HRC Forrrr 3EBA3/ ((7)

ROOT CAUSE The root cause of the 2B2 SIT depressurization was the failure of the nitrogen vent valve to reseat after opening.

The root 'cause of the 2A2 depressurization was the failure of a relief valve to reseat after opening. It could not be determined after the event whether the relief valve lifted at the correct pressure.

SAFETY ASSESSMEHT This event is not deemed reportable as per the requirements of 10 CPR 50.73.a.2.i.B, any operation or condition prohibited by the plant's Technical Specifications; however, this report is being submitted for informational purposes only.

A review of the St. Lucie Unit Two FUSAR, Sections 15.6.6.2, Large Break LOCA, 15.6.6.3, Small Break LOCA and 6.6.3.2.2, Safety Injection System Assumptions, shows that a minimum of three Safety Injection Tanks are assumed to be operable.

However, these analyses also assume the existence of other limiting parameters, including the loss of offsite power and, in the most limiting case, 75% flow from a single HPSI, 50% flow from one LPSI and 40% flow from a single charging pump. During the eight minutes that St. Lucie Unit Two was operating outside the bounds of Technical Specification 3.5.1.d, both trains of the safety injection systems were operable, all three charging pumps were operable, and off-site power was available. Therefore, of the public were not affected at any time during this event.

it can be concluded that the health and safety NRC PQRM 3OOA (943)

v'RC Form 3BBA U.S. NUCLEAR REOULATORY COMMISSIOF 19831 LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO 3150&)Os EXPIRES: 8/31/88 FACILITY IrAME (I) DOCKET NUMBER (ll I.ER NUMBER (Bl PACE (3)

YEAR 'e BEOVENTIAL M% rIEYrsrON NVMBEII w~W NVMBErr St. Lucie Unit 2 o s o o o 88 0 01 0 0 0 4 OF 0 4 TEXT ///move <<>>ce /s etu/'vsrL use /vuofo's/ HRC %%d JBSA's/ ()7)

CORRECTIVE ACTIONS A plant work order has been issued for the repair of the malfunctioning vent valve on the 2B2 Safety Injection Tank. As this work cannot be performed while the unit is at power, a caution tag has been placed on the valve hand switch on the control board in the Unit Two Control Room. The redundant nitrogen vent valve on the 2B2 SIT was subsequently tested and found to be operable.

A plant work order has been issued on the relief valve on the 2A2 SIT fill and drain line. As this valve cannot be repaired while the unit is at power, it has been isolated.

for The fill and drain line provide a path for the filling draining of the SIT to the Reactor Drain Tank; the of the 2A2 SIT and the line serves no safety-related function.

ADDITIONAL INFORMATION The specific failure modes of both of the valves will be investigated.

Com onent Information The vent valve on the 2B2 SIT is a 1" solenoid-operated glove valve, manufactured by Target Rock Valves.

The relief valve on the 2A2 SIT is a 1.5" relief valve, manufactured by Crosby Manufacturing.

For related events involving the depressurization of a SIT, see Licensee Event Reports 389-83-20, 389-83-25 and 389-83-35.

NRC FORM 3BBA (9831

P. O. Bo 00, JUNO BEACH, FL 33408 0420 MARCH 1 1988 L-88-105 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 88-01 Date of Event: February 1, 1988 2A2 and 2B2 Safety Injection Tanks Simultaneously Out of Service Due to Unrelated Valve Reseatin Problems The attached Licensee Event Report is being submitted pursuant to the rectuirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, W. F. Conw y Senior Vice President Nuclear WFC/GRM/gp Attachment cc: Dr. J. Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant GRM2/029 . LER an FPL Group company