ML20039C275

LER 81-028/03L-0:on 811118 & 1218,bistables 2-PC-431 G & I Found Out of Tolerance.Caused by Defective Potentiometer on 811118.On 811218,leads Were Tightened,Correcting Problem

ML20039C275
Person / Time
Site:	Prairie Island
Issue date:	12/18/1981
From:	Hunstad A NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20039C272	List: ML20039C271 ML20039C275
References
LER-81-028-03L, LER-81-28-3L, NUDOCS 8112290161
Download: ML20039C275 (1)

Text

NS FORM 366 U.E. NUCLEA3 REGULATO3Y COMMISSION (747)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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lh IPLE ASE PRINT OR TYPE ALL REQUIRED INFORMATIONI lo I i8 l9 lM lLICENSEE 7 N l PCODE l 1 l N l 20l@15 14 l0 l- l0 l0LICENSE l 0 NuwdER l 0 l 0 l - l 0 l260 l@4 26 l1l1l1l1l@l57 C A T 68lg LICENSE TYPE J0 l

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2111818111@ 80 EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h l o 12 l lDuring normal operation while conducting the monthly Analog Prctection Functional l 10 l 31 l Test , bistables 2-PC-431 G & I were found out of tolerance on 11/18/81 and 12/18/81 4 l o 14 l l 2-PC-431 G unblocks the safety iniection (SI) actuation logic at 2000 psig (TS l l

ITITI ITable 3. 5-3) . 2-PC-431 I actuations SI at 1815 psig (TS T^'e 3.5-1). On 11/18/81l l 016 l lboth setpoints drifted sliRhtly outside allowed tolerance. On 12/18/81.both set- l 10171 looints were drif ting alternately high and low slightly outside allowed tolerance. l lotal IRedundant channels were operable. No effect on health and safety of the public. _j C CE CO E SUSC E COVPONENT CODE S 8 ODE 3 E

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[N Jg el lY lg lN lg l F l 1l 8 l 0lg 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l3 gollBoth bistables are contained in one unit (Type 63-U-BC-OHEA-F). A defective poten-l l3 lil ltiometer in the unit was identified and replaced on 11/18/81. On 12/18/81 electri-1 m l cal leads to the unit were tightened, correcting the problem. The conditions of _j lil3l l the leads may have affected the drif t on 11/18/81 also. This unit will be closely l m Imonitored to ensure the problem is solved. l 7 8 9 80 STA  % POWER QTHER $TATU$ DISCOy RY 065COVERY DESCR'P(ION W W@ l1 l 0 l 0 lhl NA l [B_j@l Month surveillance tes t l ACTIVITY CONTENT RELE ASED OF RELE ASE AUOUNT OF ACTIVITY LOC ATION OF RELE ASE i e NA I i NA I 7 8 9 Ls.J @ LT.J@l to 11 44 45 so PERSONNEL ENPOSURES NUVBE R TYPE DESCRIPTION u LJ 10l 0101@Lz_J@l NA I PERSONNEL INJVR ES NdV9 E R DESCRI8 TION 7

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