ML17328A301

LER 88-003-08:on 880111,repetitive Violation of ESF Instrumentation Limiting Condition for Operation Tolerances Occurred.Caused by Highly Restrictive Allowable Values. Calibr Frequencies Increased to monthly.W/900622 Ltr

ML17328A301
Person / Time
Site:	Cook
Issue date:	06/22/1990
From:	Beilman T, Blind A INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-88-003, LER-88-3, NUDOCS 9007020032
Download: ML17328A301 (6)

Text

ACCELERATED UTION DEMONS'ATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9007020032 DOC.DATE: 90/06/22 NOTARIZED: NO DOCKET FACIL:50-316 Donald C. Cook Nuclear Power Plant, Unit 2, Indiana & 05000316 AUTH. NAME AUTHOR AFFILIATION BEILMAN,T.P. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele BLIND,A.A. Indiana Michigan Power Co. (formerly Indiana & Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 88-003-08:on 880111,repetitive violation of ESF instrumentation LCO tolerances due to highly RA values.

W/9 DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), 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 GIITTER,J. 1 INTERNAL: ACNW 2 2 AEOD/DOA 1' AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB 7E 1 1 LB8D1 1 1 NRR/DST/SRXB 8E 1 1 EG FILE 02 1 1 RES/DSIR/EIB 1 1 01 1 1 EXTERNAL: EG&G STUART,V.A 4 4 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHY,G.A 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! 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 34 ENCL 34

Indiana Michigan Power Company Cook Nuclear Plant P.O. Box 458 Bridgman. Ml 49106 616 465 5901 INDIANA NfCHIGiAN POWER June 22, 1990 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-58 Docket No. 50-316 Document Control Manager:

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

88-003-08 Sincerely, A.A. Blind

~ ~

Plant Manager AAB:clw Attachment CC D.H. Williams, Jr.

A.B. Davis, Region III M.P. Alexich P.A. Barrett J.E. Borggren R.F. Kroeger B. Walters Ft. Wayne NRC Resident Inspector J.G. Giitter, NRC J.G. Keppler M.R. Padgett G. Charnoff, Esp.

Dottie Sherman, ANI Library D. Hahn INPO S.J. Brewer/B.P. Lauzau W(pg 9OO/O2QQ I- Di~

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NRC FORM 366 V.S. NUCLEAR REGULATORY COMMISSION (569) APPROVED OMB NO,31500104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUESTt 500 HRS. FORWARD LICENSEE EVENT REPORT ILER) COMMENTS REGARDING BURDEN ESTIMATE TO THF. RECORDS ANO REPORTS MANAGEMENT BRANCH (F630>, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTANO BUDGET,WASHINGTON, OC20503.

FACILITY NAME (I) DOCKET NUMBER (ll PA D. C. COOK NUCLEAR PLANT - UNIT 2 0 5 0 0 03 ] 6 1 OF0 REPETITIVE VIOLATION OF ESF INSTRUMENTATION LIMITING CONDITIONS FOR OPERATION TOLERANCES DUE TO HIGHLY RESTRICTIVE ALLOWABLE VALUES EVENT DATE(5) LER NUMBER (6) REPORT DATE (TI OTHER FACILITIES INVOLVED (Sl MOIITH OAY YEAR YKAR SEOUENTIAI :rvor','EVtSK MON'TH OAY YEAR FACILITYNAMES DOCKET NUMBER(5)

NVMBEII NUMBEII

.C. COOK - UNIT 1 0 5 0 0 0 0 1 8 8 0 0 0 06 22 90 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T 0 THE RLQUIREMENTS OF 10 CF R (): (Check One or more ot the torrorrino> (11 OPERATING MODK (9) 1 20.402(tr> 20.405(c) 50.7 3(e) (2) (>v) 73.71(II)

POWER 10.405 ( ~ l(1 I I I) 60.36(c) (Il 50.73(c)(2) (v) 73.71(c)

LEVEL 0 20.405(el(1) (ii) 50.36(c) (2> 50.73( ~ )(2)(v9) OTHER (Soecity tn AOttrect Oererr ~ nd In 7ee f htRC Form 20 405( ~ l(1 l(iiil X 50 73( ~ l(2)R) 50.73(el(21(viii)(A) 366A )

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LICENSKK CONTACT FOR THIS LER (12)

T. P. BEILMAN AREA CODE TELEPHONE NUMBER MAINTENANCE DEPARTMENT SUPERINTENDENT 61 6 65- 59 1 COMPLETE. ONE LINE FOR EACH COMPONE)4T PAILVRE DESCRIBED IH THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFAC. MAHUItAC. EPORTABLE TVRER TO HFROS Iy ",~gg@r'Pk>FWmCp~ CAUSE SYSTEM COMPONENT TVRER TO NPRDS Pere Irrpr,";.-:iPN a >pWPP~,i~lyP~

SUPPLEMENTAL REPORT EXPEC'TED (14) MONTH DAY YEAR EXPECTED SUB MISS I 0 N DATE (15)

YES Iit yn, COmnrete fXPfCyfD SVSMISSIOty OATfI NO ABSTRACT ILrmtt to te(k> tercet. r, ~,, eooroeimetely Afteen tinpre toece tyoerrrrtten hnetl (16)

This revision is being submitted to reflect an update on the results of the increased frequency (monthly) calibration checks performed to date.

On March 11, 1988 an equipment trend investigation was being performed on 4KV Bus Loss of Voltage relays and the 4KV Bus Degraded Voltage relays (EIIS/EK-27).

The 'as found'ondition of these relays. during past calibration checks has generally been found to be beyond the Technical Specification (T.S.) allowable values. Each relay was adjusted to within allowable values at the time it was discovered out of specification. All relays were functional and would have performed the ESF function, although at a slightly different voltage than specified in T.S.

An engineering review has determined a plus or minus 3 percent tolerance (as opposed to the current 0.5 percent) to be acceptable for the Loss of Voltage application. The Degraded Voltage application will accept a plus or minus 1.5 percent tolerance and will r'equire installation of more accurate undervoltage relays (Design Change currently underway), A T.S. change request has been submitted. As stated in the original LER, we have increased the calibration frequency from every eighteen months to monthly.

NRC Form 366 (64)91

NRC FORM 366A US. NUCLEAR REGULA'TORY COMMISSION

)669) APPROVEO OMB NO. 31500104 EXPIRESI 4/30/62 LICENSEE EVENT REPORT (LERI ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST; 500 HRS. FORWARD COMMEN'TS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPOATS MANAGEMENT BRANCH (P.530). U.S, NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT 13')500)04), OFFICE OF MANAGEMFNTAND BUDGET,WASHINGTON, DC 20503.

FACILITY NAME 11) DOCKET NUMBER 12)

LER NUMBER LS) PAGE 13)

YEAR .'<."I SEQUENTIAL NUM SR Ill 45VISION NI/M 46 D. C. COOK NUCLEAR PLANT " UNIT 2 TEXT l///44/4 SPPCe JI /PFVPPd. I/>> Pdd/Pe/M//YRC FP//4 366A 3/ l)Tl o s o o o 3 1688 0 3 0 8 02oFO This revision is being submitted to reflect an update on the results of the increased frequency (monthly) calibration checks performed to date.

Conditions Prior to Occurrence Unit 1 and Unit 2 were operating at 90 percent and 80 percent reactor thermal power, respectively, throughout the event. There were no inoperative struc-tures, components, or systems that contributed to this event.

Descri tion of Event On March ll, 1988, an equipment trend investigation was being performed on the 4KV Bus Loss of Voltage relays (EIIS/EK-27) and the 4KV Bus Degraded Voltage relays (EIIS/EK-27). The setpoints for these relays have been found to be outside of the Technical Specification (T.S.) allowable values (T.S. 3.3.2.1 Table 3.3-4, items 8a and 8b). Of 144 individual calibrations on the loss of voltage relays over a seven year period, 68 were found to be outside of the T.S.

tolerances. Of the 66 individual calibrations performed on the degraded voltage relays over a seven year period, 41'ere found to be outside of the T.S.

tolerances. The amount of deviation from the allowable setpoint band was limited and distribution among the relays was random, indicating no particular relay to be defective. A survey of other utilities which use this type of relay revealed that the performance of our relays is consistent with their experience and within manufacturer's specifications. Each relay was readjusted to within allowable values at the time it was discovered out of specification.

The Loss of Voltage relays are installed to sense a loss of offsite or normal auxiliary power to the ESS 4KV buses. Once the loss of voltage has been sensed and after a two-second time delay, these relays in a 2/3 phases logic initiate load shedding and emergency diesel generator starting. The Degraded Bus Voltage relays are installed to sense degraded reserve power feed to the ESS 4KV buses and, on a 2/3 phases logic with a two-minute time delay, trip open the reserve Seed breakers and start the emergency diesel generators. Once the emergency diesel generator has restored bus voltage to normal, safety loads are sequenced on to the safety buses. The Technical Specifications for Units 1 and 2 have existing setpoints of 80 percent (+.5%, -1.0%) for the Loss of Voltage and 90 percent (+1.0%, -.5%) for the Degraded Grid detection. The tolerance on these setpoints are tighter than the relays can obtain, and more importantly, tighter than required for performing their intended function, i.e., sensing loss of normal voltage, initiating load shedding, and diesel starting.

NRC Fon4366A 168S)

V.S, NUCI.EAR REGULATORY COMMISSION APPROV ED OMB 'NO, S(50010<

NRC FORM S66A (689( EXPIRES; ol50(99 WTH THIS EST(MA'TEO BUROFN PER RESPONSE TO COMPLY FORWARD LlCENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST.'00 HRS. THE RECORDS COMMENTS REGARDING BURDEN 'ESTIMATE TO NUCLEAR AND REPORTS MANAGEMENT BRANCH (P 5501. U.S.

TEXT CONTINUATION REGV(.ATORY COMMISSION. WASHINGTON. DC 90555, AND TO OFFICE 1HE PAPERWORK REDUCTION PROJECT IS(500(OOI.

OF MANAGEMENTAND BUDGET, WASHINGTON, DC 90509.

REVISION PAGE (Sl DOCKET NVMBER (EI LER NUMBER L61 FACILITY NAIAE (11 SEQUENTIAL ggS YEAR NUMOER ou NVMSSR COOK NUCLEAR PLANT

" UNIT 2 D. C.

o s o o o 31 88 0 3 0 8 0 3 0F 04 JESA'Jl (IT)

TEXT illmoro Aooco lo (ouuwod. upp oddi doool lVRC Foun Cause of Event Calibration history shows a performance record in line with undervoltage relays used at other plants. We have reviewed the application of undervoltage relays for this function with other utilities and various relay manufacturers.

We have concluded that the undervoltage relays are being properly applied in this mode as a conventional protective relay. This use would not normally involve having an acceptance band. Hany utilities consulted had no Technical Specification required tolerances for this function and others had broader allowance values which more closely reflect the manufacturer's expected performance tolerances.

Anal sis of Event American Electric Power's System voltage studies have been performed and indicate that the worst case voltage on the ESS buses at the Cook Nuclear Plant would be 87.3 percent. We do not expect the ESS bus voltage to drop to a lower voltage than this unless a complete plant blackout condition occurred. Under a blackout condition, the ESS bus voltage would quickly drop well below the 80 percent undervoltage relay setpoint and initiate load shedding and diesel start.

The only function of the 80 percent voltage relays is to seme a total oss 0 f l ESS bus us v voltage. Therefore, the setpoint deviations we'e experienced translate into a different line voltage and time than the Technical Specification calls for, but the time involved for this additional voltage drop is insignificant.

The function of the degraded bus relays are to disconnect the plant from the grid for a sustained degraded condition, i.e., less than 90 percent. voltage for at least.two minutes. They are armed only when the plant is fed from offsite .

power. Plant normal configuration is to be fed from the generator auxiliary transformers except for short periods during startup and shutdown. Therefore, these relays are not normally active during unit operation.

Again, relating to our system studies, we do not believe the shift out of tolerance to be a safety problem for the degraded bus relays. Our studies indicate that the lowest possible offsite voltage to our buses would be 93.3 percent except for the short period during Reactor Coolant Pump (RCP) starting, which is less than one minute. During RCP starting, the bus voltage can dip to 87.3 percent, however, we are protected from an unnecessary trip by the two-minute time delay on this circuit.

N8 C Foun S66A (6$ 91

NRC FORM 366A V.S. NUCLEAR REGULATORY COMMISSION (689 I APPROVED OM8 NO, 3I500106 E XP IR ES: A/30/93 LICENSEE EVENT REPORT (LER) ESTIMATED 8VRDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REOVEST-, 500 HRS. FORWARD TEXT CONTINUATION COMMENTS REGARDING 8URDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP630). U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 30555, AND To 1HE PAPERWORK REDUCTION PROJECT I31504104I, OFFICE OF MANAGEMENTAND 8VDGET,WASHINGTON, DC 30503, FACILITY NAME III DOCKET NUMBER I2/

LER NUMBER IEI PAGE IS)

YEAR ': 9 66QUENNAL NUM668

'".n<Y'6' r' NUM 6 n D. C. COOK NUCLEAR PLANT - UNIT 2 0 5 0 0 0 3 1 8 8 0 3 0 8 0 TEXT /llnuup pnpco /F Puquuud, upp pddnenp/ /YRC %%d 366A 9/ I I TI An engineering review has determined a plus or minus 3 percent tolerance (as opposed to the current 0.5 percent) to be acceptable for the Loss of Voltage application. Most of the calibration history data is within 3 percent of the required setpoint. The few exceptions are considered nqrmal random failures.

The Degraded Voltage application will accept a plus or minus 1.5 percent tolerance. This value is suitable for the installation of more accurate undervoltage relays.

Based on the above, it has been concluded that there is no jeopazdy to the health and safety of the public as a result of this event.

Corrective Action The relays were recalibrated to within the allowable values at the time of discovery during the calibration. An engineering review has determined a plus or minus 3 percent tolerance to be acceptable for the Loss of Voltage application and a plus or minus 1.5 percent tolerance for the Degraded Voltage application. A Technical Specification change request has been submitted. In addition, a Design Change regarding the replacement of the currently installed Degraded Voltage relays with more accurate relays is scheduled to be completed at the next refueling outages for both units. As stated in the original LER, we have increased the calibration frequency from every eighteen months to monthly until the trend indicates a different frequency is justified.

Monthly calibration checks have yielded the following results to date:

4KV Loss of Voltage - 528 calibrations 12.3 percent 65 failures 4KV Degraded Voltage - 264 calibrations 15.5 percent 41 failures Failed Com onent Identification None.

Previous Similar Events LER 316/81-015 LER 316/82-108 LER 315/81-017 LER 315/83-069 LER 315/82-051 L'ER 315/83-094 LER 315/82-059 LER 316/82-100 NRC Form 366A I669)