ML17331B001

LER 93-008-00:on 930827,reactor Trip Occurred from Steam Flow/Feed Flow Mismatch Coincident W/Low Level in SG 4. Defective current-to-current Repeater replaced.W/930927 Ltr

ML17331B001
Person / Time
Site:	Cook
Issue date:	09/27/1993
From:	Blind A, Weber G INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-008, LER-93-8, NUDOCS 9310190104
Download: ML17331B001 (6)

Text

ACCELERATED DOCUMENT DISTRIBU I ION SYSTEM REGSTORY ZNFORMATZON DZSTRZBU3N SYSTEM (RZDS)

ACCESSION NBR:9310190104 DOC.DATE: 93/09/27 NOTARIZED: NO DOCKET ¹ FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana M 05000316 AUTH. NAME AUTHOR AFFILIATION R WEBERFG.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele BLINDFA.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 93-008-00:on 930827,reactor trip occurred from steam flow/feed flow mismatch coincident w/low level in SG 4.

Defective current-to-current repeater replaced.W/930927 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR 3 ENCL (LER),incident Rpt, etc.

SIZE:

TITLE: 50.73/50.9 Licensee Event Report NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-1 LA 1 1 PD3-1 PD 1 1 WETZEL,B 1 1 INTERNAL: AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRIL/RPEB 1 1 NRR/DRSS/PRPB NRR/DSSA/SRXB RES/DSIR/E1B 2

1 1

2 1

1 G~~

NRR/D+84~ZP LB RGN3 FILE 02 01 1

1 1

1 1

1 EXTERNAL: EG&G BRYCEFJ.H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 YOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! COYTACT THE DOCUMEYT COYTROI DESI',

I<00M I'1-37 (EXT. 50'.2065) TO ELIMINATEYOUR NAhIE FROh! DIS!'I'IBUTION D LISTS FOR DOCUhIEiTS YOU DOY,'T YEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 28 pa

Indiana Mic 'n Power Goml Cook Nuclear riant One CooK Place Bridgrnan, Ml 49106 616 465 5901 lNOlANA NI CHIGOE le POWER September 27, 1993 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-74 Docket No. 50-316 Document Control Manager:

,In accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event Re ort S stem the following report is being submitted:

93-008-00 Sincerely, A. A. Blind Plant Manager

/sb c'.

Attachment B. Martin, Region E. E. Fitzpatrick P. A. Barrett III R. F. Kroeger M. A. Bailey Ft. Wayne NRC Resident Inspector B. A. Wetzel NRC M. R. Padgett G. Charnoff, Esq.

D.. Hahn INPO S. J. Brewer B. A. Svensson gi)p 9310190104 930927 PDR ADOCK 05000316 S PDR

N4C FORM 366 U.S. NUCLEAR REGULATORY COMMI APPROVED OMB NO. 31504104 (64)9)

\ e 6 XP IR E 3.'4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPI.Y WTH THIS r'ICENSEE INFORMATION COLLECTION REOUEST: 50.0 HRS. FORWARD EVENT REPORT (LER) COMMENTS 4EGARDING BURDEN ESTIMATE TO THE RECORDS MANAGEMENT BRANCH (P630). U.S. NUCLEAR AND REPORTS REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,DC20503.

DOCKET NUMBER l2) PAGE 3 FACILITY NAME (1)

DONALD C. COOK NUCLEAR PLANT UNIT 2

(" REACTOR TRIP FROM THE REACTOR PROTECTION SYSTEM DUE TO A STEAM FLOW/FEED FLOW 050003]6 10F03 MISMATCH COINCIDENT WITH A LOW LEVEL IN NO. 4 STEAM GENERATOR EVENT DATE (5) LER NUMBER (61 REPORT DATE (71 OTHER FACILITIES INVOLVED (Sl DOCKET NUMBER(S)

MONTH DAY YEAR YEAR g SEOUENTIAL Srpm NUMBER

~~SR MONTH DAY YEAR FACILITYNAMES 0 5 0 0 0 0 8 27 93 9 3 0 0 8 ~

00 09 27 93 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT TO THE RLOUIREMENTS OF 10 CFR (); /Check one or morr Of the folfowinp/ (111 OPERATING MODE (9) 20.402 (Ii) 20A05(cl 60.73(e)(2)liv) 73.7((II) 20.405(el(1)(il 60.36(cl (1) 50.73(e ) (2) (v) 73.71(cl POWER LEY EL 50.36(c) (2) 50.73( ~ )(2)(v(i) OTHER /Sprciyy in Acr rrect 0 9 0 20A05(e) (1 I (ill Or/ow end in Fret. NRC Form 20.405( ~ )(1)(iiil d0.73(el(2) (I) 50 73( ~ l(2)(viii)(AI 3SEA/

20A05( ~ I (1) I Iv) 50.73(el(2) (iil 60.73( ~ ) l2) (viii)IS) 20A05( ~ l(ll(vl 50.73(el(2) (iii) 50,73( ~ )(2)(e)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE G. A. WEBER PLANT ENGINEERING SUPERINTENDENT 6 16 465 -5 901 COMPLFTE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) v'x(.w:j, 'c'+I'D r epee'n P '6eoS MANUFAC MANUFAC EPORTABLE CAUSE SYSTEM COMPONENT TVRER TO NPROS;4 ~  %' 4 CAUSE SYSTEM COMPONENT TVRER TO NPRDS X J K IB F 18 0 N k4~~~34 MONTH DAY YEAR SUPPLEMENTAL REPO4T EXPECTED (14)

FXPECTED SUBMISSION DATE I'I 5)

YES /f/ yn, comp/err EXPECTE/J Si///M/SS/O// DATE/ X NO ABST4ACT /Limit to fr/X/ epecn, f.r.. epproeimetely fi freen einpfr tpetr typewritrrn finn/ (16)

On August 27f 1993, at. 0502 hours0.00581 days <br />0.139 hours <br />8.300265e-4 weeks <br />1.91011e-4 months <br /> with Unit 2 in Mode 1 (Power Operation) at 90 percent Rated Thermal Power, a Reactor Trip occurred from a Steam Flow/Feed Flow Mismatch coincident with a low level in the No. 4 Steam Generator.'hese conditions were the result of an uncontrollable speed decrease on the East Main Feed Pump (MFP) Turbine. An investigation revealed that the loss of speed control was the result of a malfunctioningand Current-to-Current Repeater (I/I). I/Zs were installed in both the East West MFP Turbine speed control circuits on August 13, 1993 via a Temporary Modification (TM). This action was taken following diagnosis of a ground condition which was interfering with the transfer of the modification turbine speed control circuit from manual to the automatic controlofmode. Post testing and power operation following installation the TM demonstrated that the TM had isolated the grounding problem from the speed controller and had restored proper functioning of the control circuit. Following the was trip, troubleshooting of the East MFP speed control circuit found that the I/I malfunctioning.

The defective I/I was replaced on August 30, 1993.

the I/I, circuit checks revealed inconsistencies which ultimatelycircuits Following replacement of led to a decision to remove the TM. The East and West MFP speed control were returned to their original design on September 12, 1993. The control mode transfer problems caused by the ground condition are being controlled administratively. Trouble shooting of the ground and subsequent repairs are scheduled for completion during the next Unit 2 Outage of sufficient duration.

NRC Form 366 (669)

NRC FORM 366A US. NUCLEAR REGULATORY COMMISSIR APPROVED OMB NO. 31504)104 (64)9)

I 4 EXPIRES: 4/30(92 ESTIMATED SUADEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFOAMATION COLLECTION AEQUESTI'500 HRS. FORWARD COMMENTS REGARDING BUADEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND AEPORTS MANAGEMENT BRANCH IF@30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (31504)(04), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (I) DOCKET NUMBER (2) LER NUMBER (6) PAGE (31 YEAR SEOVENTIAL J?o? REVISION k?" NUMBER ~ .>4 NVMSER DONALD C. COOK NUCLEAR PLANT UNIT 2 o 5 o o o 3 16 93 00 8 00 0 2 OF 0 3 TEXT ((((Ro>> 4pooo jg>>9o(RR(, o>> a(Oo'oo(NRC Form JSA2 I (12)

Condition Prior to Occurrences Unit 2 was in Mode 1 (Power Operation) at 90 percent Rated Thermal Power.

Descri tion of Event:

On August 27, 1993 at approximately 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />,'perators observed the East Main Feed Pump (MFP) (EIZS/SJ-P) decreasing in speed. The Operators response to the East MFP condition was to decrease Reactor Power and take manual to control of the MFPs. The East MFP did not respond to the manual attempts increase speed and restore feedwater flow. The West MFP (EIIS/SJ-P) did respond, but could not fully compensate for the loss of flow through the East pump.

At 0502 hours0.00581 days <br />0.139 hours <br />8.300265e-4 weeks <br />1.91011e-4 months <br />, a Reactor (EZZS/JE) Trip occurred from a Steam Flow/Feed Flow Mismatch coincident with a low level in the No. 4 Steam Generator (EZIS/AB-HX).

Following the Reactor Trip, all Engineered Safety Feature systems functioned as required. One equipment abnormality was noted during the event. A spurious Chemical Volume Control System (CVCS) (EIIS-CB) Letdown Isolation resulted in a low level in the Volume Control Tank, which provides the normal supply to the Centrifugal Charging Pump (CCP) (EZIS/CB-P). Operators realigned the CCP suction to the Refueling Water Storage Tank (EIZS/BP-TK).

Following restoration of the CVCS Letdown line-up, the CCP suction was realigned to the Volume Control Tank (EZZS/CB-TK).

This event was reported as a Four Hour Report to the U.S. Nuclear Regulatory Commission Operations Center, as required by 10 CFR 50.72(b) (2) (ii). In the Four Hour Report, it was stated that the reactor at 0502 hours0.00581 days <br />0.139 hours <br />8.300265e-4 weeks <br />1.91011e-4 months <br />, and that the West MFP tripped on high exhaust hood pressure.

protection actuation occurred Upon further review, it was confirmed that the reactor protection actuation (Reactor Trip) occurred at 0502 hours0.00581 days <br />0.139 hours <br />8.300265e-4 weeks <br />1.91011e-4 months <br /> and the West MFP tripped as the result of the Reactor Trip. A High MFP Turbine Exhaust Hood Pressure Alarm was received prior to the Reactor Trip. The MFP Turbine trips at the High-High Exhaust Hood Pressure Setpoint. This trip setpoint was not reached during the transient. The Four Hour Report error was a result of misinterpreting the High Exhaust Hood Pressure Alarm as an indication of a MFP Turbine High-High Exhaust Pressure Trip, during the initial post-trip review of the Operations Sequence Monitor printout.

Cause of Event:

The decreasing speed of the East MFP was the'nitiating event leading to the Reactor Trip. The speed reduction of the East MFP was caused by the malfunctioning of the Current-to-Current Repeater (EIIS/SJ-IB) in the East MFP speed control circuit. The cause for the malfunction has not been determined.

The Current-to-Current Repeaters were installed in both the East and West MFP automatic speed control circuits on August 13, 1993, via a Temporary Modification. The purpose was to provide isolation between the pressure setter and the control circuit, protecting the control circuit from a ground problem in the pressure setter.

The cause for the spurious CVCS Letdown Isolation could not be determined.

NRC Form 355A (569)

NRC FORM 356A U.S. NUCLEAR REGULATORY APPAOVEO OMB NO, 31500104 (649)

COMMISS'ICENSEE EXPIRES: 4)30)92 ESTIMATED BURDEN PER RESPONSE TO COMP(.Y WTH THIS EVENT REPORT (LER) INFORMATION COLLECTION AEOUEST: 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION ANO REPORTS MANAGEMENT BRANCH IP430) ~ U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (315001041. OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, OC 20503.

FACILITY NAME (I) DOCKET NUMBER (2) LEA NUMBER (5) PAGE 13)

YEAR SEOVENTIAL wr4 REvlsloN N VMS 8 4 .OO ~

NVM884 DONALD C. COOK NUCLEAR PLANT UNIT 2 o 6 o o o 3 1 6 9 3 0 0 8 0 0 0 3oF 03 TEXT llfmoro opoco JI r)rrrrired, Irw 4IFF/8'onol HRC form 3664'4) (11)

Anal sis of Event:

This report is being submitted in accordance with 10 CFR 50.73, paragraph (a)(2)(IV)r as an event that resulted in an unplanned automatic actuation of the Engineered Safety Features, including the Reactor Protection System.

The automatic protection responses, including the Reactor Trip and the associated Engineered Safety Features functioned properly as a result of the Reactor Trip.

Corrective Actions:

The defective I/I was replaced on August 30, 1993. During post-maintenance checks of the East MFP control circuit, inconsistencies were discovered which prevented the automatic operation of the East MFP. This ultimately led to a decision to remove the TM for the speed control circuits of both the East and West MFPs. The grounding problem which interferes with proper transfer of the MFP Turbine speed control circuit from manual to the automatic mode of operation still exists. Should their return to automatic will be provided with the assistance it be necessary to place the pumps in manual, of I( C personnel under Administrative Controls. No other mode of controller operation is adversely affected by the grounding problem. Troubleshooting of the ground and subsequent repairs are scheduled for completion during the next Unit 2 Outage of sufficient duration.

Failed Com onent Identification: 'P Component Name: Current-to-Current Repeater Manufacturer: Foxboro Model: 66 BC-OH EIIS Code: SJ-IB Previous Similar Events:

None NRC Form K4A (649)