ML17325A679

LER 88-003-00:on 880311,discovered That Setpoints of Voltage Relays Outside Tech Spec Allowable Values.Tech Spec Change Request Will Be Submitted as Soon as Engineering Review to Evaluate Acceptable Tech Spec Values & Tolerance Completed

ML17325A679
Person / Time
Site:	Cook
Issue date:	04/11/1988
From:	Beilman T, Will Smith INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-88-003, LER-88-3, NUDOCS 8804210251
Download: ML17325A679 (7)

Text

'ACCELERATED DIFQIBUTION DEMONSTRATION SYSTEM~REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:8804210251 DOC.DATE: 88/04/11 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 SMITH,W.G.

Indiana Michigan Power Co.(formerly Indiana&Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 88-003-00:on 880311,repetitive violation of ESF instrumentation limiting conditions noted.W/8 DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE: TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.NOTES RECIPIENT ID CODE/NAME PD3-3 LA STANG,J INTERNAL: ACRS MICHELSON AEOD/DOA AEOD/DS P/ROAB ARM/DCTS/DAB NRR/DE ST/ADS 7E NRR/DEST/ESB 8D NRR/DEST/MEB 9H NRR/DEST/PSB 8D NRR/DEST/SGB 8D NRR/DLPQ/QAB 10 NRR/DREP/RAB 10 S/BP/EXS RGN3 FILE 01 EXTERNAL: EG&G GROH,M H ST LOBBY WARD NRC PDR NSIC MAYS,G COPIES LTTR ENCL 1 1~1 1 1 1 2 1 0 1 1 1 1 1 1 1 1 1 1 RECIPIENT ID CODE/NAME PD3-3 PD ACRS MOELLER AEOD/DSP/NAS AEOD/DSP/TPAB DEDRO NRR/DEST/CEB 8H NRR/DEST/ICSB 7 NRR/DEST/MTB 9H NRR/DEST/RSB 8E NRR/DLPQ/HFB 10 NRR/DOEA/EAB 11 NRR/DREP/RPB 10 NRR/PMAS/ILRB12 RES TELFORD,J RES/DRPS DIR FORD BLDG HOY,A LPDR NSIC HARRIS,J COPIES LTTR ENCL 1 1 2 2 1 1 1 1 1 1.1 1-1 1 1 1 1 1 1 1 1 1 2 2 1 1 1~1 1 1 1 1 1 1 1 1 A S A D TOTAL NUMBER OF COPIES REQUI'RED:.LTTR 45 ENCL 44 NRC Form 355 (003)LICENSEE EVENT REPORT HLER)UA.NUCL'EAR REOULATORY COMMISSION APPROVED OMS NO.3(50010l EXPIRES: BISIISB FACILITY NAME (II D.C.COOK NUCLEAR PLANT-UNIT 2 DOCKKT NUMSKR (2)PA E o 5 o o o31 6toFG4"'EPETITIVE VIOLATION.OF ESF INSTRUMENTATION LIMITING CONDITIONS FOR OPERATION TOLERANCES DUE TO HIGHLY RESTRICTIVE ALLOWABLE VALUES EVENT DATE (5(LER NUMBER (5)REPORT DATE (7)OTHER FACILITIKS INVOLVED IB)MONTH OAY YEAR YEAR gg'SOUSNTIAL ccc NUMBER NUMBER RSV~MONTH OAY YEAR FACILITY NAMES D.C.COOK-UNIT 1 DOCKET NUMBER(BI 0 5 0 0 0 3 1 5 8 8 8 8 0 0 3 00 041 188 0 5 0 0 0 OPERATINO MODE (5)POWER 0 8 0 (101 20A02((r)20.405(~)(I)(0 20A054 I (1)(S I 20 e05(~l(1)(IQ)20A054)(I)(Ir)20.4054(Il I (r)20.e05(cl 50.35(cl (I)50.35(c)(2)

X 50,734)(2((O 50 73(e HEI(S)50.734)(2I(IS)

LICENSEE CONTACT FOR THIS LER (12)50.73(el(2)(lr)50.73(e)(2)(c) 50.734)(2)(Till 50.734)(2)(TIIII(A) 50.73(el(2)(Till)(S) 50.73(eN2)(xl 0 THE AECUIREMKNTB oF 10 cFR (I: Icnecfr one or more of tne folloefrnFI (11 THIS REPORT IS SUBMITTED PURSUANT T 73.71OI)73.71(cl DTHER (Specify In Aortrect trerow emf In Text, NRC Form BBQI""" T.P.BEILMAN INSTRUMENTATION AND CONTROL DEPARTMENT SUPERINTENDENT TELEPHONE NVMBEA AREA CODE 6 164 5-5 90'1 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPOAT (13(CAUSE SYSTEM COMPONENT MANUFAC.TVAER EPOATABLE TO NPRDS SIN CAUSE SYSTEM COMPONENT MANUFAC.TUAEA EPOATABL TO NPADS N):':"~'>g

..aM o(.rN: 5%%(i eM53((%5 SUPPLEMENTAL AEPORT EXPECTED I(el YES lll yer, complete EXPECTED SUBMISSION OA TEI X NO ABSTRACT ILlmlt to ICOO tpecee, I A, epproxlmetely fifteen rlnele.rpcce typewnrten lintel (15)EXPECTED SUBMISSION DATE 05)MONTH DAY YEAR On March ll, 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 calibra-tion 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 func-tional and would have performed the ESF function, although at a slightly different voltage than specified in T.S.A survey of other plants and relay manufacturers indicate that our relays are functioning consistent with the manufacturer's specifications and that our T.S;allowable values are too restrictive for this type of function and the relay being used.We have not been able to locate replacement relays with the required setpoint sensitivity in the industry.An engineering review is in progress to evaluate the maximum allowable voltage tolerances for the two applications.

A Technical Specification change request will be submitted as soon as this evaluation has been com-pleted.In the interim, we will increase the calibration frequency from every eighteen months to monthly.8804210251 38041k PDR ADOCK 05000316 DCD NAC Form 355 rn 41~

RC fonII 358A (983)LICENSEE EIT REPORT (LER)TEXT CONTINVAQN U.S NUCLEAR REGULATORY COMMISSION APPROVED OMB NO.3150-0104 EXPIRES I 8/31/88 fACILITY NAME l11 D.C.COOK NUCLEAR PLANT-UNIT 2 OOCKET NUMBER l2I YEAR LER NUMBER (8)SEGVENTIAL NVMSER REVISION NVMSEII PAGE (3(TEXT/xmas NMcs/4/sSVEsIE s44 44UESna/HRC fsmI 3554'4/I IT(0 5 0 0 0 3 1 6 8 8 003 00 02 OF 0 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 structures, 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 o'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 were 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'th'at 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 feed 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 Unit 1 and 2 have existing setpoints of 80 percent (+.5X,-1.0X)for the Loss of Voltage and 90 percent (+1.0/.,-.5X)for the Degraded Grid detection.

The tolerance on these wetpoints are closer than the relays can obtain, and more importantly, closer than required for performing their'intended function, i.e., sensing loss of normal voltage, initiating load shedding, and diesel starting.Cause Of The 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.

NRC EORM ESSA~CVO I~U S GPO:(988 O824 538/455 M NRC Form 3SBA ($83)LICENSEE E T REPORT (LER)TEXT CONTINUA U.S.NUCLEAR REGULATORY COMMISSION APPROVEO OMB NOi 3(50&lei EXPIRES: 8/3I/88 SAC(LITT NAME (Il D.C.COOK NUCLEAR PLANT-UNIT 2 Tm(T/Pmep NMRp i/npuied, vm aSNone/NRC An/I 4548/(Ill COCKET NUMBER (ll 0 5 0 0 0 3 1 YSAII 8 8 LER NUMBER (el M~E SSCVSNT/AL Qiq REVISION NVMSSR~~NVMSSR-0 0 3-0 0 PACE (3)0 30F 0 4 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.Many 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 The Event American Electric Power's System voltage studies have been performed and indicate that the worst case voltage on the ESS buses at the 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'nitiate load shedding and diesel start.The only function of the 80 percent voltage relays is to sense a total loss of ESS bus voltage.Therefore, the setpoint deviations we'e experienced translat;e into a different line voltage and time than the Technicak.

S~oitication"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 slight 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.Based on the above, it has been concluded that there is no Jeopardy to the health and safety of the public as a result of this event.N Rc poRM SSBA IA 4'll*U.S.GPO, IBBe.o e2i 538/i55 NRC Form 3SSA (BB31 LICENSEE IehlT.REPORT (LER)TEXT CONTINU/(IN US.NUCLEAR REGULATORY COMMISSION APPROVED OMB NO.3150-0(04 EXPIRES: 8/31/88 ACIUTY NAME (11 D.C.COOK NUCLEAR PLANT-UNIT 2 TEXT/B'I/RES gad/E/dykey INS//I/ddd/HRC Fenn 38543/(171 DOCKET NUMBER (2(o s o o o YEAR 8 8 LER NUMBER (8(SECUENTIAL yg NUMBER 0 0 3 REVISION NUMBER 00 04 PAGE (3)OF 0 4 Corrective Action Equivalent relays with less drift have not been identified as available in the industry.The relays were recqlibrated to within the allowable values at the time of discovery during the calibration.

In addition, all of the relays were recalibrated from April 7-9, 1988.Out of the 36 relays for Units 1 and 2, eleven were found out of specification.

Unit 1's were last calibrated in July 1987 and Unit 2's were calibrated in February 1988.An engineering review is in progress to evaluate acceptable Technical Specifi-cation values and tolerances for the type.of relay used.A Technical Specification change request will be submitted as soon as this evaluation has been completed.

In the interim, we will increase the calibration frequency from every eighteen months to monthly until the trend indicates a different frequency is)ustified.

Failed Com onent Identification None.Previous Similar Events LER 316/81-015 LER 315/81-017 LER 315/82-051 LER 315/82-059 LER'316/82-100 LER 316/82-108 LER 315/83-069 LER 315/83-094 NRC FOAM ESSA ill ll l1'U.S.GPO:1888.0.824 538/F55 indiana Michigan Power Company Cook Nuclear Plant~P.O.Box 458 Bridgrnan, Ml 49106 616 465 5901 Z INQMNA MCHSG@N POWER April ll, 1988 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C.20555 Operating License 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:

88-003-00 Sincerely, W.G.Smith, Jr.Plant Manager WGS:clw Attachment cc: D.H.Williams, Jr.A.B.Davis, Region III M.P.Alexich R.F.Kroeger H.B.Brugger R.W.Jurgensen NRC Resident Inspector J.F.Stang, NRC R.C.Callen G.Charnoff, Esq.Dottie Sherman, ANI Library D.Hahn INPO PNSRC A.A.Blind P.A.Barrett/P.

Lauzau