ML17329A255

LER 91-007-01:on 910819,shutdown Rods Mispositioned During Attempt to Move Control Rods Due to Malfunction of Multiplexing Relay in Rod Control Sys.Multiplexing Relay MXR-1 of Power Cabinet 2AC replaced.W/911115 Ltr

ML17329A255
Person / Time
Site:	Cook
Issue date:	11/15/1991
From:	Beilman T, Blind A INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-007, LER-91-7, NUDOCS 9111200330
Download: ML17329A255 (5)

Text

ACCELERATED D14TRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9111200330 DOC.DATE: 91/11/15 NOTARIZED: NO DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana M 05000315 AUTH. NAME AUTHOR AFFILIATION BEILMAN,T.P. Indiana Michigan Power Co.

BLIND,A.A. Indiana Michigan Power Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 91-007-01:on 910819,shutdown rods mispositioned during attempt to move control rods due to malfunction of multiplexing relay in rod control sys.Multiplexing Relay MXR-1 of Power Cabinet 2AC replaced.W/911115 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER),

ENCL L SIZE:

Incident Rpt, etc.

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 COLBURN,T- 1 1 INTERNAL: ACNW 2 2 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPBll 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 LB8D1 1 1 NRR/DST/SRXB 8E 1 1 REG 02 1 1 RES/DSIR/EIB 1 1 RGN3 FILE 01 1 1 EXTERNAL: EGGG BRYCE,J.H 3 3 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 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE iVASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

Indiana Michigar~

Power Company ~

Cook Vuclear Plant One Cook Place Bridgman, Ml 49106 616 465 5901

!Ni>54&"4 R~f CH$ 6RF>>

P'O'M'CR November 15, 1991 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-58 Docket No. 50-315 Document Control Manager:

In accordance with the criteria established by 10 CFR 50.59 entitled Licensee Event Re ort S stem the following report is being submitted:

91-007-0l Sincerely, A. A. Blind Plant Manager AAB:sb Attachment c; D. H. Williams, Jr.

A. B. Davis, Region E. E. Fitzpatrick III P. A. Barrett B. F. Henderson R. F. Kroeger B. Walters Ft. Wayne NRC Resident Inspector T. Colburn - NRC J. G. Keppler M. R. Padgett G. Charnoff, Esq.

D. Hahn INPO S. J. Brewer/B. P. Lauzau B. A. Svensson

" - cry f i""00330 9 l 1:I < >

F. +DOCK 0500v31.>

F'DR

NRC PDRM366 U.S. NUCLEAR REGULATORY COMMISSION (669) APPROVEO OMB NO. 31504)104 E XPIR ES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REOUEST: 60.0 HRS, FORWARD LICENSEE EVENT REPORT ILER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (F630), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. OC 20555, AND TO THE'APERWORK REDUCTION PROJECT (3)600104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON. DC 20503.

FACILITY NAME (I) DOCKET NUMBER (2) PA E D. C. Cook Nuclear Pl ant - Uni t 1 0 5 0 0 0 3 1 5 1 oF0 3 Shutdown Rods Mispositioned During Attempt To Move Control Rods Due To Malfunction Of Multi lexin Rela In The Rod Control S stem EVENT DATE (5I LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED I~ )

MONTH DAY YEAR YEAR SEQUENTIAL REY0N MONTH OAY YEAR FACILITY NAMES DOCKET NUMBER(SI NUMBER NVMBEII 0 5 0 0 0 0 819 91 91 007 0 '111 15 9 1 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T0 THE REQUIREMENTS OF 10 CFR (): (Cnectt one or more ol rhe followfnp) (11 OPERATING MODE (6) 20A02(B) 20A05(c) 50.73(el(2) (le) 73.71(B)

POWER 20A05( ~ ) (1)(0 50M(c) (I I 50,73(e l(2)(e) 73.71(c)

LEYEL 1 0 0 20.405(el(II(E I 50.36(cl(2) 50,73(el(2)(rN) OTHE R (Specify in AOrrrect Below emf ln yexr, Hf(C Form 20A05(el(1)(IIII X 60.73(e)(21(1) 50.73(e I (2) I T)I I) IA I 366A) 8!C. e~

20A05 le) (I I (ix) 20AOS(el(II(x) 50.73(e)(2)(4) 50.73(e)(2)(IIII 50.73(el(2) (xlEI(B) 50.73( ~ l(2)(el LICENSEE CONTACT FOR THIS LER (12I NAME TELEPHONE NUMBER T. P. Beilman - Maintenance Superintendant AREA CODE 61 646 5- 5901 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANUFAC EPORTABLE ~%mZ CAUSE SYS'EM COMPONENT CAUSE SYSTEM COMPONENT MANUFAC. EPORTABLE TURER TO NPRDS ynr TURER TO NPRDS E A RLY C34 6 N iI"+VI"e

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So .,',II,, x..',$ 9 ~a@~;,;,k~'Pg SUPPLEMENTAL REPORT EXPECTED l14) MONTH DAY YEAR EXPECTED SUBMISSION DATE I15)

YES llfyN. COmplete EXPECTED SVBEIISSIOIY fJA Ml NO ABSTRACT ILlmfr to te00 rpecer, l.e.. epproxlmetely fifteen rinple.recce typewritten liner) (16)

This revision provides informaeion on the results of the root cause analysis and corrects the Failed Component Identification information.

On August 19, 1991, during routine surveillance testing of the full length rods, Control Bank A was ordered into the core by the Rod Control System but appeared not to move into the core by observation of the Analog Rod Position Indication.

Further positioning of Control Bank A resulted in an Urgent Alarm being received.

Initial troubleshooting of the Rod Control System found no reason for the Urgent Alarm and it surveillance compleeed.

was reset. The rods were moved per the test requirements and the At approximately 1200, a rod misalignment in Shutdown Bank A, Group 2 was suspected due to additional small amount of dilution required to keep thermal power at the pre-surveillance level and a decrease in the Analog Rod Position Indication for Shuedown Bank A, Group 2 in relation to pre-surveillance At 1305 hours0.0151 days <br />0.363 hours <br />0.00216 weeks <br />4.965525e-4 months <br /> the flux mapping system was used to determine that the 4readings. rods of Shutdown Bank A, Group 2 were inserted approximately 6 steps into the core.

Further eroubleshooting of the Rod Control System discovered a failure of the 2AC Power Cabinet Multiplexing Relay, MXR-1. It was replaced operation of the Rod Control Syseem was verified. The misaligned rodsandofproper Shutdown Bank A were brought out to the top of the core and normal operation resumed at 1605 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.107025e-4 months <br />. I NRC Form 366 (669)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSIO (6691 APPROV E'D OMB NO, 31500104 E XPI R E 6 I 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLl.FCTION REQUESTI 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH IP-5301. U.S. NUCLEAR AEQUI.ATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PRO4ECT l315001041, OFFICE OF MANAGEMENTAND BUDGET. WASHINGTON, OC 20503.

FACILITY NAMK (I) DOCKET NUMBER (21 LER NUMBER (61 PAGE (31 Y EA R "Q'.6 SEQUENTIAL P/'+ II6 V IS I 0 N NUMBE II .<BX NUMEEII D. C. Cook Nuclear Plant - Unit 1 0 5 0 0 0 315 9] 0 0 01 02 0 3 TEXT /// mors sPsssis ssEIIiNd, IIss sdd/0'oIIE/ NRC %%dmI 366A'4/ <<2(

Conditions Prior to Occurrence Unit One in Mode One at 100 Percent Rated Thermal Power.

Descri tion of Event On August 19, 1991, during routine surveillance testing of the full length control rods, Control Bank A was ordered 8 steps into the core by the Rod Control System (EIIS/AA) but appeared not to move into the core by observation of the Analog Rod Position Indication. Control Bank A was ordered another 2 steps into the core, leaving both group demand counters at 218 steps. The bank was ordered out of the core 4 steps and an Urgent Alarm was received. Further movement of the rods was discontinued pending investigation of the alarm.

noticed that Group 2 remained at 218 steps. The shutdown margin was then It was then verified to known plant conditions at the time.

Initial troubleshooting of the Rod Control System found no reason for the Urgent Alarm but it was noted that Power Cabinet 2AC (EIIS/AA-JX) vas selecting Shutdown Bank A instead of Control Bank A. As it was presumed to be selected by the control room, the alarm was reset and the rods were moved per the test requirements and the surveillance completed. Subsequent discussions with control room personnel indicated that no other rod bank had been selected. At approximately 1200, a rod misalignment in Shutdown Bank A, Group 2 was suspected due to additional small amount of dilution required to keep thermal power at the pre-surveillance level and a decrease in the Analog Rod Position Indication for Shutdown Bank A, Group 2 in relation to pre-surveillance readings.

At 1305 hours0.0151 days <br />0.363 hours <br />0.00216 weeks <br />4.965525e-4 months <br /> the flux mapping system was used to determine that the 4 rods of Shutdown Bank A, Group 2 vere inserted approximately 6 steps into the core and entry into Technical Specification 3.0.3 began at this time. The flux mapping system was also used to verify. that any other banks involved with Power Cabinet 2AC vere not misaligned, The banks checked were Control Bank A, Control Bank C and also Shutdovn Bank A, Group 1. At 1403 hours0.0162 days <br />0.39 hours <br />0.00232 weeks <br />5.338415e-4 months <br /> reactor power reduction began and an Unusual Event was declared.

Further troubleshooting of the Rod Control System discovered a failure of the 2AC Power Cabinet Multiplexing Relay, MXR-1 (EIIS/AA-RLY). It was replaced and proper operation of the Rod Control System was verified. When tested later on the bench, the relay exhibited fluctuating coil circui,t readings out of the circuit.

Notification of the event was made on the ENS at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />. Each of the misaligned rods of Shutdown Bank A was brought out to the top of the core, one at a time, while verifying that reactivity changes remained within limits. The Unusual Event was terminated at 1605 hours0.0186 days <br />0.446 hours <br />0.00265 weeks <br />6.107025e-4 months <br />.

Further research was conducted as to the possibility of the root cause being due to the Stationary B Firing card and/or the Signal Process card. Based on the available information and the satisfactory operating results since the event, the intermittent failure of MXR-1 is believed to be the cause of failure.

NRC FORM 366A u.s. NUCLEAR REGuLATORY COMMISSIO (649) APPROVED OMS NO,31504i04 EXPIRES, '4/30/92 tSTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) iNFORMATION COLLECTION REOVEST'00 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGtMENTBRANCH IP-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555. AND TO 1HE PAPERWORK REDUCTION PROJECT 13')504'l04). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON. DC 20503.

FACILITY NAME I'I) DOCKET NUMBER (2) LER NUMBER (6) PAGE 131 YEAR SEGUENTIAL AEVISION NUMSEA NUMBER D. C. Cook Nuclear Plant - Unit 1 o s o o o 315 91 0 0 7 01 03 OF TEXT /// mdip 44444 /4 /Pi/uiipd, u44 dddicidnu//YRC Fomi 366A3)117)

Cause of Event The rod misalignment was due to failure of the Multiplexing Relay, MXR-1, in Power Cabinet 2AC which allowed Shutdown Bank A, Group 2 to move while Control Bank A was selected.

nal sis of Event Technical Specification 3.1.3.4 addresses the situation of only one shutdown rod below the insertion limit of 228 steps (fully withdrawn). As four shutdown rods were below this limit and required entry into Technical Specification 3.0.3, this event is considered to be reportable pursuant to 10CFR50.73(a)(2)(i)(B) as an operation prohibited by the Plant's Technical Specifications.

Safety consequences of the event were evaluated and determined to be insignificant. Flux mapping measurements taken prior to the event (August 6, 1991) shows the following:

1) Margin in Heat flux hot channel factor 20.6X

2) Margin in Nuclear enthalpy hot channel factor 7.6X

3) Margin in Allowable power level 9.7X These margins can easily accommodate possible increase in peaking factors due to insertion of shutdown bank A by six steps. Also, a review of the Reload Safety Evaluation indicates an excess shutdown margin of 1817 pcm. This excess offsets any reduction in the shutdown margin due to insertion of Shutdown Bank A by six steps.

Corrective Aetio Multiplexing Relay MXR-1 of Power Cabinet 2AC was replaced and proper operation of the Rod Control System was verified. The misaligned rods of Shutdown Bank A were then brought out to the proper position at the top of the core, one at a time. Subsequent use of the control rods to complete planned shutdown activities and routine surveillance testing has been satisfactory with no similar problems occurring.

Faile Co o t d ti atio Unit One Rod Control System, Power Cabinet 2AC, Multiplexing Relay MXR-1 Plant Designation: 2-RCS-2AC, 2A1EZl Manufacturer: C.P. Clare and Company Model: HG3A-1004 EIIS Code: AA-RLY Previous Similar Events None