ML20012C723

LER 90-004-00:on 900213,loss of Emergency Bus 23-1 Occurred Due to Shorted Conductor Cable While Performing Wiring Verification.Caused by Personnel Error & Improper Installation.Electric Power Supplies recovered.W/900315 Ltr

ML20012C723
Person / Time
Site:	Quad Cities
Issue date:	03/15/1990
From:	Bax R, Fuhs A COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-004-03, LER-90-4-3, RLB-90-083, RLB-90-83, NUDOCS 9003230119
Download: ML20012C723 (5)

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Quad Chios Ndoleer Power Station 22710 206 Avenue North ooreova, Ullnois $1242 Tolophone 800/e64-2241 RLB-90-083 March 15, 1990 U. S. Nuclear Regulatory Commission Document Control Desk -

Washington, DC 20555

Reference:

Quad Cities Nuclear Power Station Docket Number 50-265 DPR-30, Unit Two Enclosed is Licensee Event Report (LER)90-004, Revision 00, for Quad Cities Nuclear Power Station.

This report is submitted in accordance with the requirements of the Code of Federal Regulations,. Title 10, Part 50.73(a)(2)(iv); The licensee shall report any event or condition that resulted in manual or automatic actuation of any Engineered Safety Feature (ESF).

Respectfully, COMMONWEALTH EDISON COMPANY QU CITIES NUCL AR POWER STATION

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. R.L.$B5 l ' Station Manager l

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l Enclosure cc: R. Stols l R. Higgins INPO Records Center NRC Region III ,

9003230119 900315 t "*g PDR S

ADOCK 05000263 PDC Yr ij 2660H a

e LICENSEE EVENT REPORT (LER) 1 . Form Rev 2.0 j.q Facility Name (1) DockCt Number (3) Pace (3) auad Citiet unit Two '

01 El 01 DI Of 1 i ) ofl0 4 Title (4) Loss of Emergency Bus 23-1 Due to a shorted 2 Conductor Cable While Performing Wiring Verification

[ vent Date fE) LER % r (6) Renart Date (71 Other Facilitiet involved fa)

Month Day Year Year //

/,p, sequential /

,/,p/ Revision eonth Day Year Facilit y Names Docket Numberft)

/// "* r /// Number 01 s1 01 O! 01 I I

~~~ ~~'

O l2 1 13 91 0 91 0 0l0 14 010 0l3 1 lE 91 0 Of El 01 01 Ol l l OPERATING fCheck one or more of the followino) (11) 1 20.402(b) 20.40s(c) .1. 50.73(a)(2)(iv) ,_. 73.71(b)

POWER ._ 20.405(a)(1)(1) 50.36(c)(1) 50.73(a)(3)(v) 73.71(c)

LEVEL 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) Other (specify f101 0 l0 l 0 20.40s(a)(1)(iii) 50.73(a)(2)(1) 50.73(a)(2)(v111)(A) in Abstract

////////////////////////// 20.40s(a)(1)(iv) 50.73(a)(2)(11) 50.73(a)(2)(viii)(B) below and in

////////////////////////// 20.40s(a)(1)(v) 50.73(a)(2)(111) 50.73(a)(2)(x) Text)

Lf t[NSEE CONTACT FOR THIS LER f12)

Name TELEPHONE NUPRER AREA CODE Anthony Fuht . Raoulatory Atsurance. Extention 3104 3 10l9 61 El 41 -l 21 21 41 1 COMPLET[ ONE LINE FOR [ACH COMPONENT FAILURE DESCRIB[D IN THIS REPORT (13)

CAusE SYSTEM COMPONENT MANUFAC- REPORTABLE CAUsE SYSTEM COMPONENT MANUFAC- REPORTABLE TURER 70 NPRDS TURER TO NPRDS 1 l l l l l l l l l l l l l _

l l I I I i 1 1 1 1 I I I I SUPPLEMENTAL REPORT [XPECTED f14) Expected Month l Day l Year submission lYet fif vet. comolate [XPECTED SUSMISSION DATE) x i N0 1 l l ABSTRACT (Limit to 1400 spaces, i.e. approximately fifteen single-space typewritten lines) (16)

On February 13, 1990, at 0818 hours0.00947 days <br />0.227 hours <br />0.00135 weeks <br />3.11249e-4 months <br />, Unit Two was shutdown and defueled with a scram ,

signal inserted. An electrical contractor, while performing a wiring verification 1 inside a control room panel, laid on a board at the bottom of the panel. The board pinched a 2 conductor cable, shorting the 2 conductors, resulting in an Engineered Safety Feature (ESF) actuation due to loss of bus 23-1 and 28.

The root cause of this event is a combination of personnel error and improper installation. Immediate corrective action was to lif t the cable leads and recover the electric power supplies. Further corrective actions will consist of proper installation

, of nec cable, training, and periodic checks of the control room panels to ensure that '

tools and materials are not left in the panels.

This report is submitted to comply with 10CFR50.73(a)(2)(tv).

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2634H/07422

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,l LittNSEE EV[NT REPORT f LER) TEXT CONTINUATIDN Fcre Rev 2.0 q ' FACILITY NAME (1) DOCKET NUMBER (8) LtR NtMatR f 6) Fane (3)

Year /// ssquential // Revision

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/// E =ha r p/ N'=har omd cities unit Two oIE l o I o I'o 12 16 It c1o - oIol4 - oI o o12 or 014

. TEXT Energy Industry Identification system ([!!s) codes are identified in the text as [xx)

PLANT AND SYSTEM IDENTIFICATION:

General Electric - Bolling Water Reactor - 2511 MHt rated core thermal power.

JVENTIDENTIFICATION: Loss of Emergency Bus 23-1 Due to a Shorted 2 Conductor Cable +

While Performing Hiring Verification A .-- CONDITIONS PRIOR TO EVENT:

Unit: Two Event Date: February 13, 1990 Event Time: 0818 Reactor Mode: 2 Mode Name: REFUEL Power Level: 00 This report was initiated by Deviation Report D-4-02-90-007 REFUEL Mode (2) - Refuel In this position interlocks are established so that one control rod only may be withdrawn when flux amplifiers are set at the proper sensitivity level and the refueling crane is not over the reactor. Also, the trip from the turbine control valves, turbine stop valves, main steam isolation valves, and condenser vacuum are bypassed. If the refueling crane is over the reactor, all  :

rods must be fully inserted and none can be withdrawn. '

DESCRIPTION OF EVENT:

On February 13, 1990, at 0818 hours0.00947 days <br />0.227 hours <br />0.00135 weeks <br />3.11249e-4 months <br />, Unit Two was shutdown and defueled with a scram signal inserted. An electrical contractor, at the direction of an architect engineer, was doing a wiring verification in the control room in a bay behind the 902-8 panel (JL] [PL). He was lying on a board which he had found lying at the ,

bottom of the bay. The feed breaker from bus 23 [EB] to bus 23-1 tripped, resulting in a loss of power to bus 23-1, bus 28 [ED], the Offgas Filter Building Transformer 20, and the A Reactor Protection System (RPS) (JC] bus. The Essential Service System (ESS) Uninterruptible Power Supply (UPS) (EF] transferred to DC power (EJ) and the Instrument bus transferred to reserve power. This caused a Reactor Building Vent (VA] and Control Room Vent [VI) Isolation (JM), Standby Gas

-Treatment System (SBGT) (BH] automatic initiation, half Group 1, 2, and 3 isolations, 2A Reactor Building Closed Cooling Water (RBCCH) (CC] pump [P] trip, 1B Instrument Air (LD] Compressor (CMP 3 trip, 2A Fuel Pool (DA] pump trip, various reactor building and turbine building fan trips, and loss of power to various drywell and torus vent valves (VTV). All of this happened as expected for the loss of buses 23-1 and 28. There was no impact on plant operations due to the unit being in a shutdown and defueled condition. This equipment was subsequently returned to normal by 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br />.

C. APPARENT CAUSE OF EVENT:

This report is being submitted in accordance with 10CFR50.73(a)(2)(iv); The licensee shall report any event er condition that resulted in manual or automatic actuation of any Engineered Safety Feature (ESF).

2634H/07422

o tittkitt EVthT ktPORT fttR) TEXT CONTIhuATION For1m Rev 2.0 FACILITY #4ME (1) DDCKET NUPSER (2) LER NUMBER f6) Pane f31 Year / sequential //g/ Revision

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/// Number /// Number nuad cities unit Two oIsIoIeIo 12 16 15 9Io - o1oIa - oI o of 3 or o la TEXT, Energy Industry Identification system (E!!s) codes are identified in the text as [XX)

The root cause of this event is a combination of personnel error and improper installation. The board had been placed on top of a 2 conductor cable which ran across the top of a grounding bar at the base of the bay. When the electrician laid on the board, the two conductors in the cable were pinched together, and eventually shorted.

The 2 conductor cable's purpose is to provide a method of attaching a recorder during the performance of QTS 110-3, Unit Two Emergency Core Cooling System (ECCS)

[JE) Simulated Automatic Actuation and Diesel Generators Auto-Start Surveillance.

This cable is a type of cable commonly used for temporary test leads, and not usually used.for panel wiring. One of the conductors connects one side of an indicating light [IL) for the bus 23 to bus 23-1 feed breaker (BKR) to a terminal board on the 902-5 panel. Another conductor in the same wire connects the other side of the indicating light to the same terminal board. Shorting these two conductors, shorted across a contact as well as the indicating light, which made up the logic to trip the breaker.

i from 0730 to 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br />, station electrical maintenance personnel had worked in this bay. They stated that they found the board lying down, set it up on end so they could stand in the bay to do their work, then laid it back down again when they were finished. They did not notice any cables across the grounding bar. At approximately 0000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />,.the contractor electrician and architect engineer came in, the electrician laid on the board to perform an inspection.

All work groups have stated that they would not knowingly lay the board on the cable. The contractor electrician who laid on the board did not know it was on the cable, and did not think to look. It was not determined who originally laid the board on the cable. The cable had been run sometime before 1979 in support of

= surveillance testing. It is not known why 2 conductor cable was used instead of panel wire and why it was run along the floor instead of the wireways.

It is very rare for contractor or station personnel to leave work equipment at the job site. The board was an exception due to ongoing inspection and work in the panels. It is not accepted practice to leave the board or any other material inside the bay. The Station has always strived and will continue to strive to maintain the plant in the cleanest possible condition at all times.

The cable not being run in the appropriate wireways is also an unacceptable work practice. The requirements the Station has implemented since 1979 would ensure this would not occur again. These requirements include the Temporary Alteration Program and Modification Program.

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1 l LffENEtt EVENT REPDRT fLER) YtKT CONTINUATION Form Rev 2.0

) FACILITY NAME (1) D0CKET NUH8ER (2) 1ER NUMBER f6) Pane f3)

,* Year Sequential Revision g// kumber

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/ humber h d Citiet Unit Two 0 l El0 l010 12 16 IE 9 iO - 010 l4 - 01 0 01 4 0F 0 14_

TEXT Energy Industry Identification system (E!!a) codes are identified in the text as (XX)

D. SAFETY ANALYSIS OF EVENT:

Unit Two was shutdown and defueled during this event, and the Reactor Building Vent and Control Room Vent Isolation and SBGT initiation all occurred as designed.

Although power was lost to the ECCS equipment fed frcm bus 23-1 and bus 28, the ECCS equipment fed from bus 24-1 and bus 29 was operable, as was the Unit Two DG which provides emergency power to these buses. Therefore, the safety significance '

of this event was minimal.

i E. CORRECTIVE ACTIONS:

'Immediate corrective actions consisted of removal of the board, unlanding and including.the wires in the Temporary Alteration Program. Bus 23-1, bus 28, and the '

associated equipment were restored to normal.

Further Corrective Actions will be as Follows:

1. The wire used in this application will be removed and replaced with an appropriate grade of wiring properly run in the wire ways (NTS 2652009000701).

'a. A policy will be adopted which will prohibit the leaving of tools or supplies such as boards, meters, wire cutters, loose spare cable, etc., in a control room panel bay whee a worker is not present (NTS 2652009000702).

3. In conjunction with panel checks that are currently being performed once per shift, the Station Control Room Engineer will be instructed to direct attention specifically to the state of the Control Room panel bays once a station policy is adopted (NTS 2652009000703).

4. This event will be discussed with appropriate station personnel (NTS 2652009000704).

F. PREVIOUS EVENTS:

No previous Licensee Event Reports were found which were similar to this event.

G. COMPONENT FAILURE DATA:

There were no component failures associated with this event.

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