ML20041B266

LER 82-002/03L-0:on 820126,main Steam Line Low Pressure Switch PS-2-261-30D Found to Trip at 794 Psig.Caused by Instrument Drift.Switch Recalibr

ML20041B266
Person / Time
Site:	Quad Cities
Issue date:	02/10/1982
From:	Kaeppel F COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20041B261	List: ML20041B260 ML20041B266
References
LER-82-002-03L, LER-82-2-3L, NUDOCS 8202230449
Download: ML20041B266 (2)

Text

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NRC FORM 366 U. S. NUCLEAR RECULOTORY COMMISSION P 77)

• LICENSEE EVENT REPORT

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CONTROL SLOCK: l l l l l l l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6 jo lil l Il .Ll Ql Al D l 2 l@l 0 l 0 l 01 -l 0l 0l 0l- l 0 l 0 l250 l@l 4l 1l Il il Il@l57 CAT LICENSE TYPE Jo l

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7 8 9 LICENSEE CODE 14 15 uCENSE NUYSER 26 COWT 10111 7 8 3E l L60 l@l 01510101012161 61 DOCKET NUMBER sl@l 68 011121618121@l 69 EVENT CATE 74 Ol 21110 75

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REPORT DATE EVENT DESCRIPTION AND PROBA8LE CONSZQUENCES h tol2l l On January 26. 1982, while performina surveillance OIS 20-1. Main Steam Line Low l IO63l l Pressure Calibration. pressure switch PS-2-261-30D was found to trio at 794 03ig. I 1014 I I This was belnw the 825 psia limit reautred by Technical Specification Table 3.2-1.1 l o I s l l No sinnificant driftino of these switches has been found since 1973. The other  !

l O is i l three switches were found operable and would have provided a Group I Isolation on l lTTT1 l low Main Steam Line pressure. Thus, the consequences were minimal. l IOlal l l 7 8 9 80 DE CO E SLBC E COVPONENT CODE SLBC DE SU E 10191 l C l 0 l@ [_Ej@ l E l@ l l l N l Sl Tl Rl Ul@ l E l@ LZ_J @

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3J 34 35 36 37 40 42 43 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h gi;Oi j This occurrence was caused by instrument drift. The PS-2-261-30D switch was  ;

li ii i i recalibrated to trip at 856 psig. No other action was deemed necessary. I Ii1211 I 1 i 131 I l l i 141 l l 7 8 9 80 ST S  % POWER OTHER STATUS 15 0 RY DISCOVERY CESCRaPTION l' I s l [G_j@ l 0 l Ol 0l@l NA l l B l@l Operator Observation l

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A TIVITY CONTENT RELEASE AVOUNT OF ACTIVITY LOCATION OF RE LEASE l i l e8 3I lz_J @D OF RELEASEL1J@l 7 to 11 NA 44 l l 45 NA 80 l

PERSONNEL EXPOSLRES I NUM8ER TYPE CESCRt# TION 39 j l1 l 7 l l 01 01 0l@l Z l@l NA l

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' 8 I NUMBER DESCRIPTION li lx I9 l301 01 Ol@l 7 ti 12 NA 80 l

LOSS OF OR DAMAGE TO FACILITY TYPE C E SCRI8 TION I i l 98 l9l 'Zl@l10 NA l 7 80 DESCRIPTION *

! ISSU

! [3_LoJ LtdL81 NA I i lll!!!!I!!!If 7 8 9 10 66 63 30 7, NAVE OF PREPARER Fred Kaeppel PsONE: 309-654-2241, ext. 171 f, 8202230449 820210

, PDR ADOCK 05000265 t S PDR ,

4 I '. LER NUMBER: LER/R0 82-2/03L-0 ll. LICENSEE NAME- Commonwealth Edison Company Quad-Cities Nuclear Power Station

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lil. FACILITY NAME: Unit Two IV. . DOCKET NUMEFD.: 050-265 V. EVENT DESCRIPTION:

On January 26, 1982, Unit Two was shutdown for a maintenance outage.

Instrument Maintenance was performing Main Steam Line Low Pressure Switch Calibration, QlS 20-1. On low Main Steam line pressure these four. switches, arranged in a one-out-of-two-twice logic, cause the Reactor to isolate by

. closing the Main Steam isolation Valves if in the RUN mode.

While performing the surveillance, one switch, PS-2-261-300, was found to trip at 794 psig. This was below the limit of 825 psig as. stated in Technical Specification Table 3.2-1. Previous Main Steam Line low pressure switch setpoint drift was reported in Quad-Cities Station deviation report numbers D-4-2-72-5 and 0-4-2-73-13 VI. PROBABLE CONSEQUENCES OF THE OCCURRENCE:

The effect of the pressure switch being out of adjustment is minimal. The other three switches were found to be within the required Technical Specification ilmit. Therefore, low pressure in the Main Steam Lines would have isolated the Reactor as designed.

Vll. CAUSE:

The cause of this occurrence was instrument setpoint drift. The pressure switch is a Bourdon tube _ type, Barksdale model number B2T-A12SS.

Vllt. CORRECTIVE ACTION:

The setpoint of the switch was re-adjusted to trip at 856 psig. The switch was then functionally tested and found to trip at 856 psig. No further corrective actions were deemed necessary.