ML20039B106

LER 81-031/03L-0:on 811109,setpoint of Standby Liquid Control Relief Valve Found to Exceed Tech Specs Range.Caused by Setpoint Drift Apparently Due to Crystallization of Sodium Pentaborate on Disc/Seat Interface

ML20039B106
Person / Time
Site:	Vermont Yankee
Issue date:	12/09/1981
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20039B098	List: ML20039B097 ML20039B106
References
LER-81-031-03L, LER-81-31-3L, NUDOCS 8112220293
Download: ML20039B106 (1)

Text

NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION

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LICENSEE EVENT REPORT LER 81-31/3L CONTROL BLOCK: l l l l l I l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6 IO lil I v l 71 v i v i si ,l@l ol of -lo lo lo lo l o l l o l o l@l 41111 l 1l 11@l57 CAT I Sa l@

7 8 9 LICENSEE CODE 14 15 LICENSE NUMBER 25 26 UCENSE TYPE JG j CON'T I

lOliI J 8 EuRCE 60 d lOl51ololol21711 61 COCKET NUMB ER hl 1 1169 l 0 IEVENT 68 9 I0 ATE 8 l 1 l@l 1121REPORT 74 75 Ol 91 OATE 81 1l@ 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h 10121 l Durine routino surveillnnce testinc of the Standhv T iould Control Relief Valves. thol a

10 l 3 l lsetnoint of relief valve SR-39-B was found to be 1540 nsic. This is conernry l i

10141Ien ehn rnnnirna vnnen nf 1 Ann-1Aon ncio nor Toch- snon- soc A AA e4nco enn I i

I o i 5 I I system has been successfully hydrotested to 2250 psig, there were no consequences I i l 016 l l rn rhn nnh140 bonleh nnd enfnfm ne n voet 1 r nf rhic nunne similnr i

IO!7Iloccurrences were reported to the Commission as LER 77-23/3L. 78-24/3L. and I IO181l80-16/1L. I 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUSCODE COMPONENT CODE SU8 CODE SUSCOCE lO19l 7 8 9 l Pl Cl@ d@ W@ l Vl Al LI Vl El Xlh I XI@ LaJ @

to 11 12 13 18 19 20

, SEQUENTIAL OCCURRENCE R9 PORT REVISION lea EVENT YE AR REPORT NO. CODE TYPE N O.

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la 11 I l-l I o l 31 il I/l I of 31 Iti l-l 1ol

._21 22 23 24 26 27 28 29 30 31 32 ACTION PUTURE EFFECT SHUTDOWN ATTACHMENT NPRO-4 PRIME COMP. COVPONENT TAKEN ACTION ON PLANT METHOD HOURS -4 SUBMITTED PORMbu8. SUPPU ER MANUFACTURER IEl@lZl@ l_Z_j@ lZl@ l oI ol ol ol (_N_j @ M@ W@ lCl7l1IOl@

33 34 35 36 37 40 41 42 43 44 47

, CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 11 101 I The deviation was attributed to setpoint drift. The suspected cause of the I i

W ldrift is crystallization of sodium nonenhorate on rho dicc/ cone intnefnco l q

1,121 l A clean up system has been installed to remove the sodium pentaborate during i g l monthly pump testing. This should reduce relief valve setpoint drif t. The l Iila1l valve was cleaned, adiusted, and reinstalled. I 7 8 9 80 ST S  % POWER OTHA STA TUS Ots O RY DISCOV ERY 0ESCRIPTION l5 I5l W h IoloIolhi NA i l,H_jhl Surveillance Test l 2 AblVITY CO TENT REuASEo OP aEuASE tOCATiON OP REu,SE @

l i I e8I 91.2.] @ 10 7

[2_l@l 11 AMOuNTOP NA 44 ACTivlTv l 45

@ NA l 80 l

PERSONNEL EXPOSURES NUV8ER TYPE DESCRIPTION 12171 I o l o l o @W@l NA l

PERSONN A'iN2u'4 ES Nuu.ER cESCRIPnON@

NA l 151811010101@l-7 8 9 11 12 80 LOSS OP OR DAMAGE TO PAC 1UTV Q TYPE DESCRIPTION N./

L!_LJlZl@l 7 8 3 to NA I 80 DE RIPTION

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81120ip PARER arren P. Murphy pgesg (802) 257-7711 {

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