ML18040A345

LER 98-004-01:on 980302,TS Required LSFT of Level 8 Trip of Main Turbine Was Missed.Caused by Knowledge Deficiency of EHC Sys.Revised Applicable LSFT Procedures Prior to Refueling Outage 6.W/980604 Ltr

ML18040A345
Person / Time
Site:	Nine Mile Point
Issue date:	06/04/1998
From:	DAHLBERG K A, WARD K D NIAGARA MOHAWK POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-004, LER-98-4, NMP2L-1788, NUDOCS 9806160140
Download: ML18040A345 (10)

Text

NIAGARA MOHAWK G EN ERATION BUSINESS GROUP NINE MILE POINT NUCLEAR STATION/lAKE ROAD, P.O.BOX 63, LYCOMING, NEW YORK 13093 dune 4, 1998'NNP2L 1788 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE: Docket No.50-410 LER 98-04, Supplement 1 Gentlemen:

In accordance with 10CFR50.73 (a)(2)(i)(B), we are submitting LER 98-04, Supplement 1,"Missed Technical Specification Required LSFT of Level 8 Trip of Main Turbine." This supplement is to clarify actions taken to correct the cause of knowledge deficiency.

Very truly yours, Kim A.Dahlberg, Plant Manager-NhG?2 KAD/GJG/kap Attachment xc: Mr.H.J.Miller, Regional Administrator, Region I Mr.B.S.Norris, Senior Resident Inspector Records Management 9806ihoi40 50004ie PDR ADQCK 0 S 0

REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)ROVED OMB NO;3!500lcl EXPIRES: ESfJMATKD BURDEN PER RESPONSE TO COMPLY Wml Tl BS INFORMATION COLLECIION REQUESf c 50AJ HRS.FORWARD COMMENIS REGARDOIO BURDEN ESAMATK TO TIES RECORDS AND REPORTS MAN AGEMENf BRANCJ I (M30), U.S.NUCLEAR REGULATORY COMM lSS ION, WAS)BNGION, DC 3M55, AND TO THE PAPERWORK REDUCIION PROJECT O1500104), OFF)CHOP MANAGEMENf AND BUDGBI;WASHINGION, DC 30503 FACK1IY NAME (I)Nine Mile Point Unit 2 DOCXEf NUMBER (D 05000410 PAGE O)1 OF 4 TIILE (4)Missed Technical Specification Required LSFT of Level 8 Trip of Main Turbine EVENI'ATE (5)MONIH DAY*YEAR gag REVISION NUMBER REPORT DATEG)MONBl DAY YEAR OTHER FACILmES INVLVED (I)FACJLIIY NAMES 03 02 98 98 0 1 06 04 98 N/A N/A 05000 05000 OPERATING MODB (9)TIES REPORT IS SUBMIITIXI PURSUANT TO THK REQUIREMENIS OF IO CFR 5: (CJ>cca c>>c c>cc>>c>cc c/dscfcJJ>>wJ>>I)(I I)POWER LEVEL (lc)J>YK~>~W 0 20.2201(b) 0 20.2203(a)(1) 0 20.2203(a)(2)Q 0 20.2203(a)(2)(ii) 0 20.2203(a)(2)(iii) 0 20.2203(a)(2)(iv) 0 20.2203(a)(2)(v) 0 20.2203(a)(3)

Q 0 20.2203(a)(3)(ii) 0 20.2203(a)(4) 0 50.36(c)(1) 0 50.36(c)(2) 3 50.73(a)(2)Q 0 50.73(a)(2)(ii) 0$0.73(a)(2)(iii) 0$0.73(a)(2)(v) 0 50.73(a)(2)(v) 0 50.73(a)(2)(vii) 0 50.73(a)(2)(viii) 0 50.73(a)(2)(x) 073.7i 0 orHHt J>CccU>I>c>Ilcc>occ aclo>>>ccc>J J>c roc, J>BC Fcc>>c 555U NAME K.D.Ward-Technical Support Manager LICENSEE CONfACf FORTIES LKR (l1).TKIZPHONB NUMBER (315)349-1043 COMPLEIK ONB ISNB FOR EACH COMPONENf FAILURE DESCRIBED IN TIES REPORT (I3)REPORTABLB TO NPRDS SUPPLKMKNFAL REPORT EXPECIKD 0O 0 YES Q'ycc, co>tpkcc ZXFECIKD S Jtul5SJOJVJMIF>J 5 EXPIATED SUBMISSION DATE (l5)MONIH DAY ABSTRACT ghsltco140cPc>ccc>ac>

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JJ>>cc)06)On March 2, 1998, Niagara Mohawk Power Corporation (NMPC)determined that the Nine Mile Point Unit 2 (MMP2)Logic System Functional Tests (LSFT)for the main turbine trip on high reactor vessel level (Level 8)failed to verify the entire circuit.This is a violation of Technical Specification Surveillance Requirement (TS SR)4.3.9.2 which is required to be performed at least once per 18 months.The cause of this event has been determined to be an apparent knowledge deficiency of the Electro Hydraulic Control (EHC)system combined with poor work practices, which led the LSFT procedure developers to conclude that the EHC panel was the actuated device.Contributing to this event was the omission of relevant information when the LSFT procedure for the Level 8 turbine trip was developed.

The circuit diagrams for the Level 8 turbine trip show the EHC panel as a circuit termination.

The applicable LSFT procedures will be revised prior to refueling outage 6 (RFO6).This event has been discussed with personnel performing the Generic Letter 96-01 procedure reviews.

0 NRC FORM 366A FACILIIY NAME (I)REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)TEXT CONTINUATION PROVED OMB NO.3)30010l EXPIRES: ESIIMATED BURDEN PER RESPONSE TO COMPLY Wml Tl IIS DIFORMATION COLLECfION REQUEST: SOA)I BLS.FORWARD COMMEÃfS REGARDBIG BURDEN ESIIMATE TO TIIE RECORDS AND REMRTS MANAGEMENI'RANCII (M30), US.NUCLEAR REGULATORY COMMISSION WASIENGfON>>

DC 3OSSSt AND TO THE PAPERWORK REDUCflON PROJECf OISOOIOQ, OFHCE OF MANAGEMENI'ND BUDGEf, WASIIINGTON, DC 20303.PAGE O)Nine Mile Point Unit 2 05000410 YEAR$98 04 REVISION NUMBER 0 1 02 OF 04 TE)ff Qnsarv tPtttt lt ttyket, sr@ofdMasd NRC iona SSSI's)P D On March 2, 1998, Niagara Mohawk Power Corporation (NMPC)determined that the Nine Mile Point Unit 2 (NMP2)Logic System Functional Tests (LSFT)for the main turbine trip on high reactor vessel level (Level 8)failed to verify the entire circuit.This is a violation of Technical Specification Surveillance Requirement (TS SR)4.3.9.2 which is required to be performed at least once per 18 months.This deficiency was identified in response to a question from another licensee concerning LSFT testing of the Electro Hydraulic Control (EHC)system.The EHC system engineer reviewed the LSFT drawings and determined that the EHC circuit had been tested from the Level 8 transmitter to an EHC panel in accordance with an LSFT procedure which references TS 4.3.9.2.The circuitry from the master trip bus within the EHC panel to the turbine stop and control valves was tested in accordance with an Instrument and Control surveillance procedure which did not specifically reference TS 4.3.9.2.However, the circuitry from the EHC panel input terminals to the master trip bus was not tested in either of the LSFT procedures.

After further review, it was found that the EHC panel circuitry from the input terminals to the master trip bus has been tested since Refueling Outage 3 in October 1993, but not by an LSFT.Work orders have been initiated with step text to perform the testing each refueling outage since RFO3.Therefore, the entire circuit has been tested since October 1993 to meet the LSFT requirements.

NMPC had performed two previous LSFT reviews and an initial review of this Level 8 LSFT as part of the overall LSFT review for Generic Letter (GL)96-01.None of these reviews identified this deficiency.

However, the NhP2 GL 96-01 process has not been completed.

A senior engineer is required to perform an independent verification of the initial reviewer's work.That verification would likely have identified this deficiency.

The cause of this event has been determined to be an apparent knowledge deficiency of the EHC system combined with poor work practices, which led the LSFT procedure developers to conclude that the EHC panel was the actuated device.Contributing to this event,was the omission of relevant information when the LSFT procedure for the Level 8 turbine trip was developed.

The circuit diagrams for the Level 8 turbine trip show the EHC panel as a circuit termination.

The cause of the individual not finding this during the initial GL 96-01 review was again knowledge deficiency and poor work practice.The individual believed that since the EHC/Turbine System is non-safety related, the actual trip of the main turbine was simply an economic issue to prevent turbine damage and not for reactor safety.Based on this, the individual did not pursue his review beyond the EHC panel input.

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NRC FORM 30SA REGULATORY COMMLSSION LICENSEE EVENT REPORT (LER)TEXT CONTINUATION PROVED OMB NO.31100I0(EXPIRES: ESTIMATED BURDEN PER RESPONSB TO COMPLY WIB I Tl BS INFORMATION COLLKCIION RE(IUESF: SOA)HRS.FORWARD COMMENTS REGARDB(G BURDEN ESIIMATETO THE RECORDS AND REPORTS MANAGEMKNI'RANCH (P>>030), UA.~REGULATORY COMMISSION, WASI BNQION>>DC 30SSS, AND TO TIIE PAPERWORK REDUCIION PROJKCP (IIS00104)>>

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DC 30S03.FACLIIY NAME (I)LKR NUMBER (6)SEQUENIIAL NUMBER REVISION NUMBER PAGE(3)Nine Mile Point Unit 2 05000410 98 04 0 1 03 OF 04 TEXT Q'~apace 4 reqafraf, me ok5danaf NRC F~30'~'s)(II)This event is reportable in accordance with 10CFR50.73(a)(2)(i)(B),"any operation or condition prohibited by the plant's Technical Specifications." The purpose of the turbine trip on high water level is to cause a reactor scram to limit the minimum critical power ratio.NMP2 Updated Safety Analysis Report (USAR)Section 15.1.2, Feedwater Controller Failure-Maximum Demand, Subsection 15.1.2.2.3, Effect of Single Failures and Operator Errors, states"In Table 15.1-3, the first sensed event to initiate corrective action to the transient is the vessel high water level (L8)trip.Multiple level sensors are used to sense and detect when the water level reaches the L8 setpoint.At this point in the logic, a single failure will not initiate or prevent a turbine trip signal.Turbine trip signal transmission, however, is not built to single-failure criterion.

The result of a failure at this point would have the effect of delaying the pressurization"signature." However, high moisture levels entering the turbine will be detected by high levels in the turbine s moisture separators, resulting in a trip of the unit." In addition, excessive moisture entering the turbine will cause vibration to the point where it too will trip the unit." Based upon these other turbine trip signals and associated reactor scram, the impact of not having this Level 8 trip is negligible.

Therefore, this event did not pose a threat to public health and safety or to plant personnel.

The applicable LSFT procedures will be revised prior to next use.2.This event has been reviewed and expectations reinforced with the personnel performing the GL 96-01 procedure reviews.The purpose of this review was to assure that personnel clearly understand that an LSFT is required to test from initiating device to the actuated device.The verification process for GL 96-01 will specifically address the LSFT circuit scope as part of the verification review.The verification reviews are scheduled for completion by the end of RFO6.Since the personnel who originally developed the EHC-LSFT procedures are no longer employed at NMPC, and Corrective Action 2 assured a thorough review, no additional training is warranted.

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FACLrrY NAME (I)UA.REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)TEXT CONTINUATION PROVED OMB NO, 3 I 300104 EXPIRES: ESrMATED BURDEN PER RESPONSE TO COMPLY Wm(T)BS B(FORMATION COLLECIION REQUEST: 50A)HRS.FORWARD COMMENTS REGARDE(G BURDEN ESBMATE To THE RECORDS AND REPORTS M ANAGEM ENr BRANCH (M30), US.NUCLEAR REGULATORY COMMISSION WASHINGPON>>

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none.B.Previous similar events: NMP2 has had a number of instances where procedure preparation or review caused missed or inadequately performed surveillance tests.In accordance with NMPC's Corrective Action Program, a Deviation/Event Report (DER)was initiated to evaluate this trend.A root cause team was assembled to evaluate this overall trend to determine if process problems or other common aspects could be identified.

Required corrective actions will be taken as necessary to correct any identified deficiencies in accordance with the corrective action program.C.IdentiGcation of components referred to in this LER: g>>??(?0?i',.",R>>S4>>(r0!

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