ML20012C493

LER 90-004-00:on 900213,control Room B HVAC Intake Radiation Monitor Lost Power Causing auto-start of Emergency make-up Train B.Caused by Blown Fuses.Fuses Replaced.Logic Revs for Radiation Monitors Will Be installed.W/900315 Ltr

ML20012C493
Person / Time
Site:	LaSalle
Issue date:	03/15/1990
From:	Diederich G, Sanders L COMMONWEALTH EDISON CO.
To:	Office of Nuclear Reactor Regulation
References
LER-90-004-02, LER-90-4-2, NUDOCS 9003220068
Download: ML20012C493 (4)

Text

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Commonweahh Edison

. L7Salle County Nuclear Station Rural Route #1, Box 220 Marseilles, Illinois 61341 Telephone 815/357 6701 l

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March 15, 1990 1

i Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D.C. 20555 .

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Dear' sir:

Licensee Event Report #90-004-00, Docket #050-373 is being sutaitted to your office in accordance with 10CFR50.*13(a)(2)(iv).

i O j O. J. Di&*erich (Station Manager LaSalle County Station GJD/LRS/kg Rnclosure xc: Nuclear Licensing Administrator NRC Resident Inspector NRC Region III Administrator INPO - Records Center I

900322 C6 H

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' LICENSEE EVf W1 REPORI (LER)

, g Facility Name (1) Docket Noter (2) _Paae (3)

LaSalle M ty Station Unit 1 01 51 01 01 01 31 71 3 1lofl0l3 Title (4) Automatic Start of Control houm Emergency Make-up Ventilation Train Oue to slown Buses on the Control a - Radiation Monitor Event Date (5) LER thster (61 Report Date (7) Other Facilities involved (8)

Month Day Year Year // Sequential / Revision Month Day Year Facility Names Docket thstter(s) ff

/// thster //j/ Ne$er ff

//

LaSalle Unit 2 01 51 01 01 01 31 71 4 01 2 11 3 91 0 91 0

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01 0 0l3 11 5 91 0 0151010101 l l TH15 REPORT 15 $UBMITTED PURSUANT 10 THE REQUIREMENTS OF 10CFR OPMING (Check one or more of the followine) (11)

MODE N ,X_ 50.73(a)(2)(lv) 73.7)(b) 1 20.402(b) _ 20.405(c) _

POWER _ 20.405(a)(1)(l) _ 50.36(c)(1) _ 50.73(a)(2)(v) _ 73.71(c)

LEVEL 20.405(a)(1)(ll) 50.36(c)(2) 50.73(a)(2)(vil) _

Other (Specify i _ _ _

(10) 1I 0 0 _ 20.405(a)(1)(111) _ 50.73(a)(2)(l) _ 50.73(a)(2)(vill)(A) in Abstract

/,/,/,/,/,/,/,/ /,/,/ /,/,/,/,/,/,///,/,/ / _ 20.405(a)(1)(lv) ,,_ 50.73(a)(2)(ll) _ 50.73(a)(2)(vill)(B) below and in 50.73(a)(2)(lli) 50.73(a)(2)(x) Text) ffff

////'/'fj///'//'

fff' ffj/ /}f/////

ff/ 20.405(a)(1)(v)

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LICENSEE CONTACT FOR THIS LER (12) ,

Name TEtEPHONE NUSER AREA CODE Leon R. Sanders. Technical Staff Eneineer, extension 2701 0 l 1 15 315171-l6171611 CO W LETE ONE tlWE FOR LACH LOMPONE FAllURE DESCRIBE 0 IN 1HIS REPORT (13)

CAUSE SYSTEM C090NENT MANUFAC- REPORTABLE CAUSE SYSTEM COMPUNENT MANUF AC- REPORTABLE TURER TO NPRDS TURER TO NPRDS X ii t l l FI U Gl 01 81 2 N l l l l l l l l l 1,1 1 I I I I I I I I I SUTLEMENTAL REPORT EXPECTED (14) Expected Month l Day l Year Submission

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lyes (If ves, cauolete EXPECTED SUBMISSION DATE) YlNO I ll ll ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16)

At 1645 hours0.019 days <br />0.457 hours <br />0.00272 weeks <br />6.259225e-4 months <br /> on February 13, 1990, with Units I and 2 in Operational Condition 1 (Run) at 100% and 96% power respectively, the "B" Control Room HVAC (VC) Intake Radiation Monitor 2018-K7518 lost power causing an auto-start of the "B" VC Emergency Make-up (EMU) train. Per design, the system realigned to the pressurization mode of operation. Investigation of the radiation monitor revealed that the two (2) 1 agere fuses for the "28" VC Radiation Monitor Trip Unit 24 volt power supply were blown. The reason for the two blown fuses is unknown. The safety consequences of this event were minimal since the "B" VC system responded to the radiation monitor trip signal per design. Corrective actions included replacing the two 1 agere fuses for the "28" VC Radiation monitor Trip Unit 24 volt power supply and channel checks verified that the readings were approximately the scite before the loss of power and after the power was restored to the unit.

Since being returned to service,1Lhe radiation monitor has experienced no further problems. Modification 1-0-88-003 will Install logic revisions for the VC radiation monitors to require more than one detector to cause an actuation of the system.

This event is repytable pursuant to the requirements of 10CFR50.73(4)(2)(iv) due to the actuation of an Engineered Safety teature (ESF) system.

-- g _ a ,

tWMEE EVENT EPORT (LER) TEXT CONilduAfl0W Foss Rev 2.0 i Paae (3) i FACILlif IIW (1) DOCKET NueER (2) LER NumER (6)

Year /// Sequential g/jr Revision fff

/// thster /// thster L M te County station unit 1 0 1 5 1 0 1 0 1 0 1 31 71 3 9IO - 01014 - 01 0 01 2 0F 01 3 TEXT Energy Industry identification System (Ell 5) codes are identified in the text as [XX]

I PLANT AND $YSTLM IDEN11FICAT10N 1

1 General Electric - Bolling Water Reactor EnergyIndustryidentificationSystem(Ells)codesareidentifiedinthetestas(XX).  :

A. CON 0! TION PRIOR TO EVENT Unit (s): 1/2 Event Date: 2/13/90 Event Time: 1645 Hours ___

Reactor Mode (s): 1/1 Mode (s) Name: Run/Run Power Level (s): _100E/965 l

8. DESCRIPil0N OF EVENT ,

On February 13, 1990 at 1645 hours0.019 days <br />0.457 hours <br />0.00272 weeks <br />6.259225e-4 months <br /> with Units 1 and 2 in Operational Condition 1 (Run) at 1005 and 965 respectively, the "B" Control Room HVAC (VC) (Vl] Intake Radiation Monitor 2018-E7518 (F1) [IL) lost i power causing an auto-start of the *8 VC E1mergency Make-up (EMU) train. Per design, the "B" VC train ,

realigned to the pressurization mode of operation. At the time of this event, the "A" VC system was operating in Rectrculation Mode with the minimum outside air danpers open and flow through the charcoal ,

adsorber. The "B" VC EMU train was placed in Pull-to-Lock (i.e., shutdown and prevented from automatically starting) and a 7-day time ctock was started in accordance with Technical Specification 3.7.2. ,

Upon investigation it was determined that the two (2) 1 aspere fuses for the "28" VC Radiation Monitor Trip Unit 24 volt power supply were blown. The fuses were replaced per LaSalle Astninistrative Procedure LAP-400-11 which restored power to the "28" VC Radiation Monitor Trip Unit. A channel check of the VC s

Radiation Monitors had been performed per LaSalle Operational Surveillance LOS-AA-52 approalmately 5 alPJtes before the loss of power to the "28" trip unit. When power was restored to the unit it was l

verified that the reading was approximately the s ee as before the loss of power.

On february 13, 1990 at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> the "B" VC EMU train was taken out of Pull-to-Lock and the "B" VC EMC '

train and the "28" VC Radiation Monitor 2018-K7518 were declared operable.

This event is reportable pursuant to the requirements of 10CfR50.73(a)(2)lv) due to the actuation of an ,

Engineered Safety feature (ESf) System.

C. APPARENT CAUSE OF EVENT lt was found that two (2) 1 aspere fuses for the "28" VC Radiation Monitor Trip Unit 24 volt power kupply were blown. The reason for the two blown fuses is unknown. There were no calibrations or work being done on or near the "28" VC Radiation Monitor Trip Unit 24 voit power supply at the time of the l event.

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L - -. . .

. LICENSEE EVENT REPORT (LER) TEXT CONTINUATION f orm Rev 2.0 FACILITY NAME (1) DOCKET Nu mER (2)- LER NUSER (6) Pace (3)

Year /// Sequentla) // 7jj/ Revision fjj

/// Weber /// Neber LaSalle County Station unit 1 o I 5 I o I o I o i 31 11 3 9Io - oIoIa - oI o 01 3 0F 01 3 TEXT Energy Industry identification System (Ells) codes are identified in the text as (XX]

D. SAFETY ANALYSIS OF EVENT The safety consequences of this event were minimal since the "B" VC system responded to the radiation ,'

monitor trip signal (ESF) actuation per design.

E. CORRECTIVE ACTIONS The two (2) I aspere fuses for the "28" VC Radiation Monitor Trip Unit 24 volt power supply were replaced. A channel check of the VC radiation monitors had been performed per LOS-AA-52 approximately 5 minutes before the loss of power and again after power was restored to the "28" Trip Unit. The channel checks verified that the readings were approximately the same before the loss of power as after the power was restored to the unit. Since being returned to service, the radiation monitor has experienced to further prob 1ms. >

Modification 14-88403 will install logic revisions for the VC radiation monitors to require more than one detector to cause an actuation of the system.

F. PREVIOUS EVENTS There are no previous events of blown fuses causes a VC radiation monitor to actuate.

G. COMPONENT FAILURE DATA Manufacturer Nomenclature Model Number MFG Part Number p

Little Fuse Fuse,1 Amp NA 313001 125V, 3AG, Slo Blow r

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