ML20043E912

LER 90-006-00:on 900508,Unit 2 RCIC Declared Inoperable Due to Unstable Operation of RCIC Pump Flow Controller.Caused by Proportional Band of Controller Being Set to Respond to Changes in Flow Too Quickly.Flow controlled.W/900607 Ltr

ML20043E912
Person / Time
Site:	Quad Cities
Issue date:	06/07/1990
From:	Bax R, Hill K COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-006-07, LER-90-6-7, RLB-90-145, NUDOCS 9006130517
Download: ML20043E912 (6)

Text

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3, Commonwealth Edison Quad Cities Nuclear Power Station 22710 206 Avenue North

' Corcova, Illinois 61242. .

Telephone 309/664 2241 RLB-90-145 June 7, 1990- .,

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L. l j h .U. S N'uclear Regulatory; Commission l Document Control; Desk-Washington,-DC 20555 i i

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Reference:

Quad Clties Nuclear Power Station

, Docket-Number 50-265, DPR-30, Unit Two l- i L

Enclosed is Licensee Event Report (LER)90-006, Revistor, 00, for Quad Cities t l ' Nuclear Power Station. j

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-This report is submitted in accordance with the requirements of the Code of -r Federal Regulations, Title-10, Part 50.73(a)(2)(v)(D): The'llcensee shall' report any event or condition that alone could have prevented the fulfillment 1 of.the safety function of structures or systems that are needed to mitigate the consequences of an accident. .

Respectfully, ,

COMMONHEALTH' EDISON COMPANY- i QUAD CITIES NUCLEAR POWER STATION ptB

[ R,L.. x

. Station Manager >

'RLB/HJB/jt i

Enclosure

l. cc: R. Stols l T. Taylor

, 2 INP0 Records Center I od NRC Region III 2823H 9006130517 900607 -

-POR ADOCK 05000265 S PDC 11 f I l

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[ LICENSEE EVENT REPORT (1.ER) 7 ,p,y 3,g

.- Fac'111ty Mame (1) Docket Number (2) Pace f31 Dus'd Cities Unit Two 01 El 01 of 01 21 61 5 1 !of 0 E Title (4) -

Unit Two RCIC Incoerable Due to New Flow Controller Instability Found Durino Initial Installation Testino. j Event Date (El LER Number (6) Report Date (7) Other Facilities involved (8)  !

Month Day Year Year // Sequential /p,/,/ Revision Month Day. Year Facilit y Names Docket Numberfs)

/p,/p

// Number /// Number 01 El 01 01 01 I l

~~ ~"

01 5 01 8 91 0 91 0 0 1016 010 0l6 01 7 91 0 01 El 01 01 Ol' i l THIS REPORT Is SUBMITTED PUR$UANT TO THE REQUIREMENTS OF 10CFR .

(Check one or trere of the followinct fill 4 20.402(b) _ 20.405(c) __ 50.73(a)(2)(iv) 73.71(b)

POWER 20.405(a)(1)(1) _ 50.36(c)(1) 2L 50.73(a)(2)(v) 73.7)(c) i LEVEL 20.405(a)(1)(ti) 50.36(c)(2) 50.73(a)(2)(vii) Other (Specify  !

(101 0l2 l3 20.405(a)(1)(iii) 50.73(a)(2)(1) ._ 50.73(a)(2)(v111)(A) in Abstract

////////////////////////// __ 20.405(a)(1)(iv) __ 50.73(a)(2)(11) _ 50.73(a)(2)(viii)(B) below and in

////////////////////////// 20.405(a)(1)(v) _ 50.73(a)(2)(111) 50.73(a)(2)(x) Text)

LICENSEE CONTACT FOR THIS LER (12)

Name TELEPHONE NUMBER AREA CODE K. J. Hill. Technical Staff Enoineer Ext. 2150 3 10 19 61 51 41 -l 21 21 41.,,1 COMPLETE ONE LINE FOR EACH COM FAILURE DES {g! BED IN THIS REPORT f131  !

CAUSE SYSTEM COMPONENT MANUFAC- REPORTABLE CAUSE SYSTEM COMPONENT MANUFAC. REPORTABLE TURER 70 NPROS TURER TO NPR05 l

! I I I l l l I I l l- 1 i l I  ;

I I I I I i i i I I I I I I I SUPPLEMENTAL REPORT EXPECTED f14) Expected Month i Day I Yeg submisston lyes fif yet. complete EXPECTED SUBMISSION DATE) X l No l l i ABSTRACT (Limit to 1400 spaces, i.e. approxtmately fifteen single-space typewritten lines) (16) .[

ABSTRACT-

j At 1912 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.27516e-4 months <br /> on May 8, 1990, Quad Cities Unit Two was operating in the RUN mode at i 23 percent of noted core thermal power. At this time, the Unit Two Reactor Core i l Isolation Cooling (RCIC) system was declared inoperable due to unstable operation of the RCIC pump flow controller, FIC-2-1340-1, during performance of RCIC Manual Initiation Test, QOS 1300-7.

l The cause.of this event is being attributed to the response of the newly installed i

controller to changes in flow being too quick which resulted in unstable flow oscillations.

The proportional band setting of the new flow controller was adjusted and the system was successfully tested and declared operable at 2235 hours0.0259 days <br />0.621 hours <br />0.0037 weeks <br />8.504175e-4 months <br />, on May 8, 1990, i.

This event is being reported according to 10CFR50.73(a)(2)(v)(D).

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LICENSEE EVENT REPORT-(LER) TEXT CONTINUATION- Ferm Rev 2.0 FACILITY,NAME (1) .

DOCKET NUMBER (2) LER ktMBtR (6) Pane (3) i3  : Year sequential Revision

Number Number

,0uad Cities Unit Two 0l510l0 l0 l 21 61 1 9 l' 0 - 0 10 l6 . O I f) 01 2 0F 01 5

~. TEXT = Energy Industry Identification system (t!!s) codes are identified in the text as [XX]

hlANT'AND'SYSTEMIDENTIFICATION:

General Electric - Boiling Water Reactor - 2511 MWt rated core thermal power.

EVENT IDENTIFICATION: Unit Two RCIC Inoperable Due to New flow Controller Instability.

Found During Initial Installation Testing.

A. CONDITIONS PRIOR TO EVENT:

Unit: Two Event Date: May 8, 1990 Event Time: 1912 Reactor Mode: 4 Mode Name: RUN Power Level: 23%

This report was initiated by Deviation Report D-4-2-90-023 RUN Mode (4) - In this position the reactor system pressure is at or above 825 psig, and the reactor protection system is energized, with APRM protection and-RBM interlocks in service (excluding the 15% high f flux scram).

B. DESCRIPTION OF EVENT:

At 1912 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.27516e-4 months <br /> on May 8, 1990, Quad Cities. Unit Two was operating in the RUN mode at }

23 percent of rated core thermal power. At this time, the Unit Two Reactor Core '

Isolation Cooling (RCIC) (BN] system was declared inoperable due to unstable operation of the RCIC pump [P] flow controller [TC), FIC-2-1340-1, during performance of the RCIC Manual Initiation-Test, 005 1300-7. This testing was in progress as a new RCIC pump flow controller had been installed prior to this event under modification M4-2-88-378. .y The RCIC manual initiation test is performed to verify system operation u.nder  !

actual auto-initiation conditions. With the RCIC system lined-up for normal l standby operation, the system is initiated by depressing the manual initiation .;

pushbutton at control room panel [PL] 902-4. The startup sequence is then j

,1dentical to that required in an auto-initiation, including valve [V) actuation and j injection into the reactor [RCT) vessel [RPV). A strip chart is connected at panel ]

902-4 to record turbine [TRB] speed, pump discharge pressure ~and pump discharge j flow to the vessel for base data reference purposes. J At 1835 hours0.0212 days <br />0.51 hours <br />0.00303 weeks <br />6.982175e-4 months <br /> on May 8, 1990, RCIC Monthly and Quarterly Test. 00s 1300-1, was -

successfully completed and the Operating Department prepared for performance of '

QOS 1300-7.

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3 4 LICENEff TVENT RtPORT f LERl TEXT CONTINUAT10N Form Rev 2.0'

FACIt.!TY[NAME (1) DDCKET NUMBER (2) LER NUMBER f6) Pace f31 N_ Year /// seguential Revision -l jj/

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f Number /j//

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/ __N' h Quad Cities Unit Two 0lEl010 1 0 l 21 61 5 9_l 0 - 010l6 - 0 10 01 1 0F DI E TEXTc Energy Industry Identification system (Ells) codes are identified in the text as (XX)

After depressing the RCIC manual initiation pushbutton for QOS 1300-7, all valve I actuations~ occurred ~as designed and the initial turbine acceleration transient was controlled by the turbine ramp generator. As the turbine accelerated, pump flow overshot the flow controller.setpoint and hit the high end of the scale, 600 gallons per minute-(gpm). This was followed by a quick reduction of pump flow to O gpm. ~ Pump flow began oscillating from the high to the low end of the scale at a

. j rate.of once'every 3 seconds.  ;

The Unit Two Nuclear Statio'1 Operator (NS0) switched the flow controller to the manual mode and_was able to control pump flow. While maintaining flow manually at 400 gpm, it was noted that pump flow varied approximately plus or minus 3 gpm.

Af ter'several minutes of manual operation, the NSO switched the flow controller back to the automatic mode. Pump flow remained steady for several seconds but eventually began oscillating slightly and increasing to the severe oscillations as before. The NSO tripped the RCIC system using the turbine trip pushbutton. '

At 1912 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.27516e-4 months <br /> on May 8- 1990, the Unit Two RCIC system was declared inoperable due to the inability of the pump flow controller to control flow in the automatic mode. RCIC system outage report, 00S 1300-01, was initiated and Nuclear Work Request 084556 was. written for Instrument Maintenance (IM) personnel to investigate and repair. NRC notification of the event via_.the Emergency Notification System (ENS) phone system was completed at 2140 hours0.0248 days <br />0.594 hours <br />0.00354 weeks <br />8.1427e-4 months <br /> on May 8, 1990, to comply with the requirements of 10CFR50.72(b)(2)(t11)(0). *

.Approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following the initial failure, the test was repeated with IM  ;

personnel _in attendance. The turbine responded as before and the NSO took manual control to maintain 400 gpm. The IHs reviewed the strip chart of pump flow, discharge pressure and turbine speed taken during the startup. It appeared that

'the wide swing of the newly installed pump flow controller was a result of the controllers proportional band needing adjustment. The controller was responding to

.the changes in flow, but the rate at which it corrected flow was too_ quick and as a result it caused unstable flow oscillations.

With the RCIC-turbine in operation, the proportional band of the flow controller was increased to effectively respond to the system characteristics. Following this adjustment, the flow controller was switched to the automatic mode and operated satisfactorily.

-The RCIC Manual Initiation Test was successfully completed at 2235 hours0.0259 days <br />0.621 hours <br />0.0037 weeks <br />8.504175e-4 months <br />, on a May -- 8, ' 1990. The Unit Two RCIC system was declared operable and the outage report

terminated.

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i Form Rev 2.0

?? LICENSEE EVENT.REPDRT fLER) TEXT CONTINUATION

.FACId TY.hAME (1) DOCKET NUMBER (2) .

LER NUMBER f6) Pace f3) $

Year sequential Revision l

Number Number

• buad Cities Unit Two 0 l' & l 0 l' 0 l 0 l 2161 $ 910 - 01016 - 0 l0- 01 4 0F of E TEXT Energy Industry Identification system (Ells) codes are identified in the text as [XX) '

C. . APPARENT CAUSE OF EVENT:  :

LThis event is being reported according to 10CFR50.73(a)(2)(v)(D): the licensee

.shall~ report any event or condition that alone could have prevented the fulfillment of thel safety function of structures or systems that are needed to mitigate the

< consequences of an accident.

The instability of the flow controller was caused by the proportional band of the controller being set to respond to changes in flow too quickly which resulted in >

unstable flow conditions.

The RCIC pump flow controller 1s new and was recently installed during a refuel outage prior to this event. The initial calibration of.the controllers was

. identical to the previous controllers except for-the proportional band. As a result of data obtained from identical controllers installed on Unit One, the a proportional band of the Unit Two RCIC controller was decreased prior to l installation in order to provide a quicker response. 1

-D.? ' SAFETY ANALYSIS OF EVENT: J s )The safety of the plant and personnel was not affected in this event. The RCIC ,

system automatically initiates on-reactor low-low water level-(-59 inches) [JE] and is designed to provide core cooling water in the event the reactor becomes isolated

from the main condenser (SG) simultaneously with a loss of the reactor feedwater system [SJ]. -The RCIC system is not part of the station Emergency Core Cooling Systems-(ECCS) and is therefore not required for a Loss of Coolant Accident (LOCA).

s The' instability of the RCIC flow controller would have prevented turbine operation

. in the automatic mode but would not have prevented automatic system inttlation.

Once the system had initiated, the operator could have taken manual control to a

provide necessary pump flow, i iThe instability of the flow controller affected the operability of the-RCIC system for only a short time period from the time of startup from the refuel outage to the '

time that the problem was detected. This would include the time from reaching

-reactor criticality at 0541 hours0.00626 days <br />0.15 hours <br />8.945106e-4 weeks <br />2.058505e-4 months <br /> on May 7, 1990, to the time of this event at 1912 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.27516e-4 months <br /> on May 8, 1990.

Per Technical Specification 3.5.E, when RCIC is found to be. inoperable, continued reactor operation is permissible provided the High Pressure Coolant Injection (HPCI)'[BJ) system is operable. In addition to HPCI providing a backup to RCIC, othe Safe Shutdown Makeup Pump (SSMP) is a motor driven pump designed as a backup to ,

'RCIC as part of the station safe shutdown analysis. The SSMP was available

_throughout this event, and HPCI was available at all times except for overspeed testing from 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on May 7, to 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> on May 8', 1990.

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LICENE(( EVENT REPDRT fLER) TEXT CONTINUAfl0N' Form Rev 2.0 '

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.F%CILITY2NAME (1). '00CKET N(MBER (2)  ! LER NUMBER f6) Pace'f3)

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Year /// sequential // Revision .[

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Quad Citiet Unit Two oi510l0 l' o 8 21615 910 - 01016 - 0 l0 01 5 0F 0! E _

,; TLXTj: Energy Industry Identification system (Ells) codes are identified in the text as (XX]' I

'i E. CORRECTIVE ACTIONS: $

The.immediate corrective action consisted of switching the flow controller to

-manual-to control pump flow. After a second failure to maintain automatic flow.

control, the turbine was manually tripped, the outage report initiated and a work ,

request written to: investigate'and repair.

Investigation by IM personnel determined the problem to be due to the proportional.  !

band of the new flow controller needing adjustment. The proportional band setting -

, 'of the flow controller was increased to respond to system characteristics and the '

turbine was successfully tested and declared operable.- 1

Although not affecting system operability, it was noted that small flow i oscillations existed =in the RCIC system. The System Engineer will investigate the ,

. source of the RCIC system flow oscillations (NTS 2652009002301).

'F. PREVIOUS EVENTS:

There are previous events involving instability of the original type RCIC and HPCI ,

pump flow controllers. However, this is a new controller and was in the process of initial installation testing. No search of'the Nuclear Plant Reliability Data 3 System (NPRDS) was performed as there was no compor,ent failure identified in this i event.

I G.-lCOMPONENTFAILURE-DATA:

-l There was no component failure associated with this event.

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