ML20006E398

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LER 89-008-01:on 890228,reactor Vessel Low Water Level 2 Switch Found W/Setpoint in Excess of Reject Limit.Caused by Setpoint Drift.Channel Placed in Tripped Condition & All Static-O-Ring Pressure Switches to Be replaced.W/900214 Ltr
ML20006E398
Person / Time
Site: LaSalle Constellation icon.png
Issue date: 02/14/1990
From: Diederich G, Jacklin N
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
LER-89-008-01, NUDOCS 9002230055
Download: ML20006E398 (6)
v • d • e


Text

r, Commonw:cith Edison LaSalle CountyNuclear Station

, RuralRoute #1, Box 220-l: e : Marsell:es, Illinois 61341 L- ' Telephone 815/357-6761' M '

February 14, 1990 L

K Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stati.on P1-137 Washington, D.C. 20555 l 1

Dear Sir:

Licensee Event Report #89-008-01, Docket #050-373 is being .J j

submitted to your office to supercede previously submitted i Licensee Event Report 89-008-00 which was reported pursuant to NRC 1.E. Bulletin 86-02, " Static-O-Ring Differential-Pressure Switches."

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/ l ho G. J. DiedIrich 1

g) Station Manager LaSalle County Station l GJD/NWJ/kg l l

Enclosure xc: Nuclear Licensing Administrator NRC Resident Inspector NRC Region III Administrator INPO - Records Center i

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LICENSEE EVENT REPORT (LER) - F w Rev 2.0 .

Docket Nunber (2) Pane (3) (

- fccility Name (1)

LaSalle County Station Unit 1 01 51 01 01 01 31 71 3 I of!0 5 Title (4)., 4 I Setsoint Orift of Reactor Wessel Law Water Level (Level 2) Switch LER Nueer (6) Report Date (1) Other Facilities involved (8)

I. Event Date (5)

Sequential Revision Month Day Year Facility Names Docket thaber(s)

Month Day Year Year Nueer Nunber ,

L 0151010101 l l el 9 el 9 010Ie

~01 1 012 11 4 91 0 01 51 01 01 01 I I 01 2 21 e THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10CFR b

  1. N^ (Check one or more of the followina) (11) i 20.402(b) ,,,,_ 20.405(c) _ 50.73(a)(2)(lv) ,_,,,,, 73.71(b) p 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) ,,_,,, 73.71(c)

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20.405(a)(1)(111) 50.73(a)(2)(1) 50.73(a)(2)(vill)(A) in Abstract-

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LICENSEE CONTACT FOR THIS LER (12) l TELEPHONE NUSER Name-AREA CODE i

Ned W. Jacklin, General Engineer, extension 2397 8 l 1 15 315111-l6171611 COWLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT- MANUFAC- REPORTA8LE CAUSE MANUFAC- REPORTABLE SYSTEM'l COMPONENT- TURER' TO Q, TURER TO NPRDS X Al 0 l Pl 01 S Sl31812 Y l l l l l l l l I I l i I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED (14)

Expected Month l Day i Year Submission lyes (if ves. complete EXPECTED SUBMISSION DATE) X l NO l ll ll ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16)

At 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br /> on February 28, 1989, with Unit I at 76% power, Reactor vessel low Water Level 2 switch LS-1821-#026CB was found with its setpoint out-of-tolerance in excess of its Reject Limit during the routine perfonnance of a surveillance.

In spite of the out-of-tolerance setpoint, LS-1821-N026CB would have properly perfonned its Primary Containment Isolation functions as required in the event of reactor low water level because its "As Found" setpoint (including an accounting for static pressure effects) was still-within the Technical Specification Limiting Condition for Operation.

Static-0-Ring differential pressure instruments which exceed their Reject Limits are rejected from further service and replaced. The switch replacement and calibration were conpleted by 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br /> on March 1,1989.

The rejected instrianent was disassembled and inspected. Nn definite cause of failure was detennined.

Nothing ebnormal was found. The level switch which precipitated this event was replaced by an analog trip system during the third refueling of Unit 1.

This event is voluntarily reported to the Nuclear Regulatory Consission in compilance with the requirements of Inspection Enforcement Bulletin 86-02.

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'" LtesaK U EVENT REPORT (LIR) TEXT CONTINUATION Form Rev 2.0 00CKET NUMER (2). LER WNSER (6) -Pee (3)

FACILITY NAE (1)l Sequential //,/, Revision

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  • ile C 4v Station Unit I' 0 l 5 1 0 1 0 1 0 1 31 71 3 8l9 ~ - - 01010 -- 0 l '1 01 2 0F 01 5 [

TEXT: ' ' Energy' Industry _ identification System (Ells) codes are identified in the text as _[XX]

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[PLANTANDSYSTEMIDENTif1CAil0N' General Electric - Bolling Water Reactor.

Energy Industry identification System (Ells) codes are identified in the text as [XX].

~A.. CONDil10N PRIOR 10 EVENT

_ Unit (s):- I' Event Date: 2/28/89 Event ilme: 0910 Hours  !

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Run Power Level (s):

765 p Reactor Mode (s): 1 ' Mode (s) Name: q L-

l. . B. DESCRIPTION OF_ EVENT Reactor Vessel (WB) [ADJ-Low Water Level 2 Switch LS-1821.#026C8 was found with its setpoint .

out-of-tolerance in excess of its Reject Limit in the non-conservative direction. - This discovery was ,

Leade at 0910 hours0.0105 days <br />0.253 hours <br />0.0015 weeks <br />3.46255e-4 months <br /> on February 28,1989'during .the. routine performance of LaSalle Instrument ,

o surveillance LIS-NS-102l _" Unit 1; Reactor Vessel Low Low Water Level (Level 2) Primary and Secondary:~

- Contalmnent Isolation Calibration." Unit I was operating at 76% of rated power at the time.

The "As Found" setpoint for LS-1821-N026CB'was 143.5 inches of water column ("WC), corresponding to

~ 47.2 inches of indicated reactor water level (" R ). The desired setpoint of this switch at -

' atmospheric pressure is -33.8 +/- 1.4 "RWL. Accounting for static pressure shift:(2.5 "WL per

. LST.46-156 for this particular switch) the actual as found setpoint was -50.55 "WL, which means thef

' switch would have operated 6.45 inches above the Technical Specification Limiting Condition for j

. Operation of >/= -57 "RWL. See Figure'l. ,

q C. . APPARENT CAUSE OF EVENT.

This' event was apparently causN by setpoint drift. The instrument was disassembled and inspected at the station to attanyt to determine the cause of the failure. No definite cause of failure could be l determined and nothing abnormal was found. No damage or other abnormalltles were found. ]

h D.  : SAFETY ANALYSIS OF EVENT This event did'not degrade plant safety.

The switch's actual as found setpoint, accounting for static shift, was -50.55 "RWL at reactor

_ pressure. :ThisLis well within the Technical Specification Limit'.ng condition for operation of -57 "WL. Thus all safety systems would have functioned as designed in the event of a low water level

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_i condition'in the reactor vessel.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION LER NUSER (6) Pace (3) s.. FACILITY NAME (1) DDCKET NUSER (2)

Year Sequential // Revision

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01018 0l I 01 3 0F 01 5 lI fl L @ lle County Station Unit 1 0 l 5101010131713 819 - -

TEXT Energy Industry identification System (Ells) codes are identified in the text as (XXJ

-E. CORRECTIVE ACTIONS l

As required by the SOR Differential Pressure Switch long Tenn Action Plan, SOR differential pressure switcheswhichdriftbeyondtheirrejectlimitsareconsideredtechnicallyinoperable. Accordingly, LS-1821-N026C8 was declared inoperable and the channel placed in the tripped condition at 1008 hours0.0117 days <br />0.28 hours <br />0.00167 weeks <br />3.83544e-4 months <br /> on  ;

february 28, 1989. The replacement and calibration of the switch was coupleted on March 1, 1989 and the channel was declared operable by 0645 hours0.00747 days <br />0.179 hours <br />0.00107 weeks <br />2.454225e-4 months <br /> on that date.

Work Request L87899 was written to replace this rejected instrument (serial neber 85-4-284) with an identical instrument certified for use at LaSalle (serial nunber 86-9-2673). Therejectedinstrument was disassembled and inspected by the station to attengt to determine the root cause of failure.

Nothing abnonnal was found. A long tenn plan is in effect to replace all SOR level switches with ,

Rosemount analog trip systems. The switch which caused this event was replaced under Modification M-1-1 096 during the Unit I third refuel outage.

F. -PREVIOUS EVENTS

  • l LER Nunber Title 374/86-007-00 Excessive Static-0-Ring Pressure Switch Drift 374/96-011-01 Failure of 12.S* DP Level Switch to Respond to Low Level 374/96-019-01 Reactor Vessel Low Level Confinned ADS Pennissive Switch Out of Tolerance Due to Setpoint Drift 373/87-010-01 Automatic Depressurization System Low Level Confinned Switch Setpoint Found Out of Tolerance Due to Setpoint Drift .

374/87-011-01 Residual Heat Removal Pung Mininnan Flow Bypass Differential Pressure Switch Found out of Tolerance Due to Setpoint Drift 373/88-028-01 Setpoint Drift of Reactor Vessel Low Water Level Switch 373/88-029-01 Setpoint Drift of Low Level Confinned Automatic Depressurization System Pennissive Switch 374/88-005-01 High Pressure Core Spray Minimum Flow Bypass Flow Switch Out of Tolerance Due to Setpoint Drift 374/88-013-01 Low Pressure Core Spray Minimum Flow Bypass Differential Switch Found Above RejectionLimit 374/88-015-01 Residual Heat Removal Pup Minimum Flow Bypass Differential Pressure Switch Found Out of Tolerance Due to Setpoint Drift 373/89-003-00 Setpoint Drift of Reactor Vessel Low Water Level Switch 373/89-005-01 Main Steam High Flow Switch Out-of-Tolerance Due to Setpoint Drift 373/89-004-01 2AResidualHeatRemovalMinimumFlowBypassSwitchFoundGreaterthanRejectLimit During Surveillance Testing 374/89-006-01 Setpoint Drift of Low Level confinned Automatic Depressurization System Pennissive Switch

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y~- g Form Rev 2.0  ;

" E LICENSEE EVENT REPORT (1.ER) TEXT COWilNUAT10N' LER NUSER (6) J gie (3)  ;

o FACILliY NAE (1) ' DOCKET NUSER (2) >

Sequential Revision -;

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, ' TEXT: ' Energy Industry identification System (Ells) codes are identified in the text as [XX]  !

G; . COMPONENT FAILURE DATA

, Manufacturer Nonenclature Model Essber MFG Part Number ,

103-AS 4212-NX-CI A- NA SOR, Inc. Differential Pressure Switch JJITX6 [

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Year, // Sequential Revislon ]

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t @ lle County Station Unit 1 0 1 5 1 0 1 0 1 0 1 31 71-3 819 -

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. TEXT ' Energy Industry identification System (Ells) codes are identified in the text as [XX). .

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i 4 I F100RE'1

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'1 Inches Of Indicated i Reactor Water Level l 1

-21.90" g

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- -  ; -2 6 .'40 " ] I l

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> -32.40" Desired-Reject- Action; . Setpoint -l l Limitz .. Tolerance -33;80"- Setpoint .,-

Limits ,

- . Atmos. Press i L l *

.> -35.20" i l

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t- -  ; -41.40"

-45.80" "As Found" Setpoint (Atmospheric Pressure)- + .

-47.10" Technical Specification Nominal Setpoint > -50.00" L' Calculated Trippoint (Rated Pressure) + -50.55" Technical' Specification Limit + -57.00"

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p Figure 1: Static 0-Ring Setpoint Information

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