ML17266A398

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LER 80-071/03L-0:on 801231,during Operation at 100% Power, Vol Control Tank Inadvertently Diluted,Leading to RCS Dilution,Increasing Power Above Tech Specs Limit.Caused by Failed Crosby Relief Valve V2173 on Acid Pump Discharge
ML17266A398
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 01/29/1981
From: Pace P
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17209A641 List:
References
LER-80-071-03L, LER-80-71-3L, NUDOCS 8102180653
Download: ML17266A398 (3)


Text

N AC FORM SSS P TTI t.lCEiNSEE EVCIMT REPORT U.S NUCl.SAR REGULATORY COMMISSION CONTROL SLOCIKI I I I!QI (PLEASE PAINT OA TYPE ALl, A'EOUIRKD INPOAMATIONI I~FILIAL EIIIQ0 01-001010101.0 0Q411 I III IQ~Q 4 9 UCKNSKS COOK LICSiu$4 EEIUMBER lS TS L;CL'4$4 TYPE l0 ST~T$4 CCN'T 0 I 2 RKPQAT LLLQS 0 5 i 0 0 i[!QT 40 4 I QOCXET NVMSSR 49 SV SNT OKSCRIPTION ANO PROSASL,S CO44SSOUSEHCSS QIO Ourin normal o eration at 100K ow r ,Q8 IO!4 0 ll 2I I Q>I inadIFertentl diluted leadin t I cated reactor ower increased over about 15 mini~Q ls, l Tc also increased durin the transient reachin 542 5 the s~a>>l.imit is 542 f.Action er T.S.3.2.5.u(as taken and d COMP, VALVE CCMPONENTCQQK SVSCQQS'VBCQOS 8 WXQIS mQ IS I9 OCCUAAKiICS REPORT REVISION'QQE TYPE~NO.L~J Laic~L3-laJ l 3*T.ACNM SAT'IPPIO44 PRIME COMP.COMPONENT 22 SVSMITTEO POAM$US.SVPPUKR MANUSACTUAKR Lue LJO I IS LOcFS eg 41 43 44 4T SYSTEM CA VS 4 CA VS S C QS COOK SUSCCOS ELLLie IFJS LEJQ 1 4 9 10 I I IS IS SSQUSNTI*l LERIRO eVKNTYSAA A SPORT NO.Qi;~EFEFEF~BP TI TT 23 34 TS 4'CH PUTUAK EJPEC.SNVTQCWN SE~ACTION CN PLANT MKTIIQO HQV AS'SLJS LJS LJO CALSS OKSCRIPTlON ANO CORRSCilVS ACTIONS Q2l o I!Mhile addin makeu and d'0~or!reduced.This is the first event of this t e.~04 T 3!relief valve V2173 Crosb st le JR-MR-S ailed returnin boric l uostream from the relief was normal T and later re aired.~AQSI n>>'MES~i<S~E T 4 3 IO I'3 IS 44~EnTY C NTS.'IT~SLe~io QP RELEASE AMOUNTOP ACTIVITY QSS~I!>>~Z QSS~ZQ24 NA T 3 IO I I PSRSONNK EXPOSURES NUMSER QSSCAIPTION 2 L0000 0'Q>>~ZLQE qlA T 5 I I I'3 IS P$1$CNNSL INlURIK3~LBOOOIQ$$QP CA OAMAQ S,Q PAOLITY Q42 SS QESCRIPTIQN

~ZQ42 NA T 4 3'g PUBLIC:~0.

ISSUSO QESCRiPT:QN S~20 LN IQ~NA 44 45 IO 8102 18OI'P53.NAMA OP PREPARER P.L.Pace.4 saCIIL'~~20 MKTIIOO QP$.ATUS-ei POWER OTIIKR STATUS Q CISCOVERY 40 I 40 40 NRC USE ONLY 44 39 30 (305)552-3801 QI SCOV KR Y 0 ESCA LATICN QS2 0 erator Observation LOCATION OP RELEASE Q2 NA REPORTABLE OCCURRENCE 335-80-.71 LICENSEE EVENT REPORT PAGE TWO ADD ITIONAI CAUSE DESCRIPT IOfl The chargino pumps';which take suction on the YCT, pump..bora'ted water~into the RCSfor boron concentration control and makeup.llhile blending boric acid and water to the VCT to slightly dilute the RCS and add make-up', a relief in the line to the blending valve failed.This returned the boric acic.'o the boric acid makeup f'ink instead of into the VCT.This resulted in the dilution of the VCT and therefore the dilution of the RCZ.The plant is designed to safely accomodate this transient but the event is potentially significant due to the misleading indication given.The relief valve is downstream from the boric acid flow element so the operators had indication of'a normal blend to the VCT.Due to the small amount of acid involved (a few gallons)and the large boric acid tank size (8,000 gallons), tank level did not respond with notice-able indication.

Increasing power was the first indication of the transient and the cause was not readily apoarent.Since dilution via the VCT is a slow process, the transient had been in orogress for several minutes before there was any indication.

An alternate boron injecticn path was used to reduce power.The relief was disassembled and found to have a cut seat and a bent stem.Th seat was repaired and the stem replaced.The bent stem was the root cause of the dilution.How the stem became bent is unknown.A review by Plant Operators of this LER and of the proper actions taken, will increase awareness of this problem and will help the operator to deal with similar events, should they occur in the future.

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