ML20006F595

LER 90-001-00:on 900122,RWCU Sys Received Div 1 Leakage Detection Ambient Temp High Isolation Signal,Causing Trips of RWCU Pumps a & C.Caused by Broken Thermocouple Input Lead.Lead Wire Reconnected & Isolation reset.W/900221 Ltr

ML20006F595
Person / Time
Site:	LaSalle
Issue date:	02/21/1990
From:	Diederich G, Kollross T COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-001-06, LER-90-1-6, NUDOCS 9002280213
Download: ML20006F595 (4)

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N: H .Commow:calth Edison:.

s LaSalle CountyNuclear Station'

' RuralRoute #f. Box 220 i

. Marseilles, Illinois 61341'

. Telephone 815/357 6761

<' February 21,.19901  !

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Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Station Pl-137 Washington, D.C. 20555

Dear Sir:

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' Licensee Event _ Report #90-001-00, Docket #050-373 is being

. submitted to your, office in accordance with .

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10CFR50.73(a)(2){iv).-

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. J.'Diederich hgStationManager LaSalle County Station GJD/CTK/kg t

. Enclosure' j xc: Nuclear Licensing Administrator .I NRC Resident Inspector NRC Region III Administrator INPO - Records Center 1

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LICENSEE EVENT REPORT (LER) F e Rev 2.0 Docket Number (2) Pane (3)

Facility Name (1)

IA11e County Station Unit 1 01 51 01 01 01 31 71 3 1lofl0!'3 l Title (4)

Reactor Water Cleanuo Isolation Due to ;;.aen TMa^9_=_le Lead Durino Surveillance Testinc Report Date (7) Other Facl11tles involved (8) l R M Cate (5) LER Number (6)

Revision Month Day Year Facility Names Docket Number (s)

Month Day Year Year /g//

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/// thaber W/ thaber 01 51 01 01 01 1 I oIoI1 01 0 o12 21 1 91 o 01 51 01 01 ol i I i 01 1 21 2 91 0 91 0 TulS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10CFR

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(Chock one or is of the followine) (11)

" 1 20.402(b) ___

20.405(c) _X , 50.73(a)(2)(iv) ,__, 73.71(b) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c)

POER _ 20.405(a)(1)(1) __,,, _

Other (Specify LEVEL 20.405(a)(1)(ll) ,_,_

50.36(c)(2) ,,,,,_ 50.73(a)(2)(vil) ,,,,_

in Abstract i (10) 0l 9! T ___ 20.405(a)(1)(lli) _,,_

50.73(a)(2)(l) ,,_,_ 50.73(a)(2)(vill)(A) 50.73(a)(2)(vill)(8) below and in l h //// / //////// ///// 20.405(a)(1)(lv) _ 50.73(a)(2)(ll) ,,_,,

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50.73(a)(2)(lli) 50.73(a)(2)(x) Text)

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LICENSEE CONTACT FOR THIS LER (12)

TELEPHONE IlUIBER Name AREA CODE 8 l 1 15 31 51 71 -l 61 71 61-1 Todd Ko11ross. Technical Staff. extension 2772 wsETE ONE LINE FOR EACH wriH WT FAllilDE DESCR18E0 IN THis REPORT (13)

CAUSE SYSTEM COMPONENT MANUFAC- REPORTA8tE CAUSE SYSTEM COIF 0NENT MANUFAC- REPORTABLE TURER TO HPRDS TURER TO IIPRUS l l l N l l l l l I 1

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,1 1 I I I I I Expected Month l Day l Year SUPPLEIENTAL REPORT EXPECTED (14)

Submission

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lyes (If ves. : =lete EXPECTED SUBMISSION DATE) YiNO l l ll ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16) l~ Dn January 22, 1990 at 2058 hours0.0238 days <br />0.572 hours <br />0.0034 weeks <br />7.83069e-4 months <br />, with Uait 1 in the Operation Condition 1 (Run) mode at 97% power, the Reactor Water Cleanup (IndCU) System received a Olvision 1 Leakage Detection (LD) Anblent Temperature High-L i Isolation Signal causing the IndCU Outboard Isolation Valve to automatically close followed by automatic trips

' cf the A and C RUCU pumps. This event occurred during a Main Steam (MS) [S8] Tunnel High Area Vent p

Differential Temperature Isolation Functional Test. During this test, as an Instrument Maintenance Technician was attempting to gain access tc the nain Steam Tunnel Differential Tenperature Switch thennocouple input leads, a fleid thennocouple input lead broke at the adjacent RWCU Heat Exchanger Room "A" Anblent Tesiperature Switch. At that moment, the 1t1C0 System received a Olvision I LD Mblent Tenperature High Isolation Signal, which caused a iniCU Suction Line Outboard Isolation. The technician lamediately relanded the loose lead.

The IndCU isolation was reset and the IndCU System was restarted at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on January 22, 1990. The root cause of this event has been detennined to be a problem involving the method of tenninating the temperature sensor leads at the Riley switches.

This event is reportable to the requirements of 10CFR50.73(a)(2)(iv) due to the actuation of an Engineering Safety Feature system.

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0 1 0'l 1 '- 01 0 01 2 '0F 01 3 [

0 1 5 1 0 1 0 1 0 1 31 71 3 9'l 0

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tatalle' taunty Station Unit 1" -

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

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1PLAlli AllD SYSTEM 10ENTiflCAT10N .

~ General Electric - Dolling Water Reactor-

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

' A. . CONDITION PRIOR 70 EVENT 1/22/90 Event Time: _ 2058 Hours D ' Unit (s):.. Y I . Event Date: I Run Power Level (s): 975

' Reactor Mode (s): 1 - Mode (s)'Name:

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, , 8. . DESCRIPTIGN OF EVENT x{ on January 22,'1990 at 2010 hours0.0233 days <br />0.558 hours <br />0.00332 weeks <br />7.64805e-4 months <br /> with Unit 1 in.the Run Mode at 97% power,-Instrument Maintenance (IM)- i

' technicians began performing LaSalle Instre ent Surveillance LIS-MS-305, " Unit 1 Main Steam Tunnel High I Area Want Differential Temperature Main Steam Isolation Valve (MSIV) Isolation functional Test." At-k }~

'o 2058 hours0.0238 days <br />0.572 hours <br />0.0034 weeks <br />7.83069e-4 months <br />, the IM technician began moving wires from Unit 1 Division 1 Reactor Water Cleanup (RWCU)

. [CE) Heat Exchanger Room ?At Anblent Temperature Switch,1E31-41615A, to gain access to the lead ' wirr for the Main Steam (MS) [58] Isolation Differential Temperature Switch, IE31-4160lG. During this -

process', a fleid themoccuple input lead broke off of the teminal associated with temperature' switch j'

.1E3141615A.o The technician,irealizing what had happened, lsmediately relanded the disconnected lead and' j notified the Control Room Iluclear Station operator (1150, 11 censed Aeactor Operator). At that time, the 'f

10. System had received a Division 1 Leakage Detection (LD) [CE] Anblent Temperature High Isolation -

This was cSignal, and;the 100C0 Outboard Isolation Valve,1G33-f004,' automatically closed isolating falCU.

followed by an automatic trip of the A and C 1h100 puups due to low suction line flow. .All equipment involved operated as designed under the given~circunstances.

.The 150C0 isolation was reset and the IndCU System was restarted at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> onlanuary 22, 1990. 3

_l This event is' reportable pursuant to the requirements of 10CFR50.73(a)(2)(lv) due to the actuation of an

' Engineered Safety Feature System.

E x s C. -APPARENT CAUSE OF EVENT f

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-The cause of the IndCU Outboard Valve Isolation event was due to a thermocouple input lead which broke.

,l - off Temperature Switch IE31-41615A during LIS-MS-305. These leads have to be noved slightly in order fcr Jf survelliance testing of their related instruments and tend to break at the switch due to tM brittleness

^of the tharnocouple utre.

The root cause of this event has been determined to be a problem involvir.g the method of terminating the  ;

temperature sensor leads at the Riley switches.

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LICMEE EVENT REPORT (LER) TEXT CONTINUATION Form Rev 2.0  ;

FACILITY IIME (1) DOCKET trUleER (2) LER 1RWWER (6) Pace (3) l Year /f/

f Sequential //

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Revision j

/T/ thaber // Nember l

% 11e County Station unit 1 015101010131713 9Io - 010l1 - 01 0 013 0F 01 3

? TEXT Energy Industry iden*,1fication System (Ells) codes are identified in the text as [XX]

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O. SAFETY ANALYSIS OF EVENT The falCU Suction Line Outboard Isolation and subsequent shutdown of the IndCU System had no lapact on the safe operation of Unit 1. TS-1E31-4861SA tripped and caused a IndCU Suction t.ine Outboard isolation as designed. The IndCU System was shutdown due to the isolation from January 22, 1990 at 2058 hours0.0238 days <br />0.572 hours <br />0.0034 weeks <br />7.83069e-4 months <br /> to 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />. During that time, reactor coolant conductivity remained well below the 1.0 micronho per ,

centimeter square allowable Ilmit as specified in Techtilcal Specification 3.4.4.

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~ E. CORRECTIVE ACTIONS ~1 l

On January 22, 1990, a thermocouple input lead from Temperature ^.,wltch IE31-41601G broke during l LIS-4tS-305. The technician, realizing what had happened, inmediately reconnected the Ivad wire. By 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />, the IndCU isolation was reset and the 1tf00 System was restared.

An investigation is in progress to detennine a suitable method of terminating the tenperature sensor .

leads to minimize the occurrence of lead failure at the Riley switches. Action item Record 374-200-88-02601 is trMking this investigation.-

F. PREVIOUS EVENTS None.

G. COMPONENT FAILURE DATA Manufacturer Nomenclaturo Model Number MFG Part Number Riley Temoe.ature Switch Temp-aatic 861 N/A l

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