ML18016A384

LER 98-004-00:on 980313,design Deficiency Related to Indequate Runout Protection for Turbine Driven AFW Pump Was Identified.Caused by Inadequate Original AFW Sys Design. Evaluation (ESR 98-00100) Will Be completed.W/980409 Ltr

ML18016A384
Person / Time
Site:	Harris
Issue date:	04/13/1998
From:	Donahue J, Verrilli M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HNP-98-050, HNP-98-50, LER-98-004, LER-98-4, NUDOCS 9804170044
Download: ML18016A384 (9)

Text

CATEGORY 3y REGULA ORY INFORMATION DISTRIBUTION SYSTEM (RZDS)

FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina DOCKET 05000400 I

AUTH. NAME AUTHOR AFFILIATION VERRILLI,M. Carolina Power S Light Co.-

DONAHUE,J.W. Carolina Power 8 Light Co.

RECZP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 98-004-00:on 980313,design deficiency related to indequate runout protection for turbine driven AFW pump was identified. Caused by inadequate original AFW sys design. A Evaluation (ESR 98-00100) will be complete r DISTRIBUTION CODE: IE22T COPIES RECEIVED LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc. E NOTES:Application for permit renewal filed. 05000400@

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL R PD2-1 PD 1 1 FLANDERS,S 1 1 Y

INTERNAL: ACRS 1 1 AEOD SPD RAB 2 2 AEOD/SPD/RRAB 1 1 CENT 1 1 NRR/DE/ECGB 1. 1 NRR7DE/KE 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 D RES/DET/EIB 1 1 RGN2 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 0

1 1 LITCO BRYCE,J H 1 1 NOAC POORE,W. 1 1 NOAC QUEENER,DS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 U

N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOW ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 25 25 ENCL

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Carolina Power & UcJht Company Harris Nuclear Plant PO Box 165 New Hill NC 27562 APR -9 1998 U.S. Nuclear Regulatory Commission Serial: HNP-98-050 ATTN: NRC Document Control Desk 10CFR50.73 Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT.UNIT 1 DOCKET NO. 50-400 LICENSE NO. NPF-63 LICENSEE EVENT REPORT 98-004-'00 Sir or Madam:

In accordance with 10CFR50.73, the enclosed Licensee Event Report (LER) is submitted. This LER describes a design deficiency related to a potential runout condition occurring with the Turbine Driven Auxiliary Feedwater Pump during certain accident scenarios.

Sincerely, J. W. Donahue Director of Site Operations Harris Plant MV Enclosure

'c: Mr. J. B. Brady (HNP Senior NRC Resident)

Mr. L. A. Reyes (NRC Regional Administrator, Region II)

Mr. S. C. Flanders (NRC - NRR Project Manager) 9804170044 9804i3 PDR ADQCK 05000400 S PDR

~vvU i 4 5413 Shearon Harris Road New Hill NC

NRC'FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB No. 3160%104 EXPIRES 04/30/96 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH TIOS MANDATORY UIFORMATION COILECTION REDDEST: 50/I HRS. REPORTED lESSONS lEARNED ARE LICENSEE EVENT REPORT (LER) NICORPORATED UITO THE UCENSUIG PROCESS AND fEO BACK TO UIDUSTRY.

fORWARD COMMENtS REGAROUIG BURDEN ESTIMATE TO THE DIFORMATION ANO RECORDS MANAGEMOIT BRANCH ITS FSSL US. NUCLEAR REGULATORY COMMISSIOIL (See reverse for required number of WASHINGTOIL DC 20555400). ANO TO THE PAPERWORK REDUC'TION PROJECT ISI50 digits/characters for each block) 0104L OFFICE OF MANAGEMENT ANO BUDGET, WASHINGTOIL OC 205IKL FACIUTY NAME I'l DOCKET NUMBER I2) PACE Isi Harris Nuclear Plant Unit-1 50-400 1 OF 3 TITLE I4I Design deficiency related to inadequate runout protection for the Turbine Driven APW Pump.

EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (6)

FACILITY NAME DOCKET NUMBER SEOUENTIAL REVISION MONTH OAY YEAR YEAR MONTH OAY YEAR NUMBER NUMBER FACILITYNAME 3 13 98 98 004 00 13 98 DOCKET NUMBER 05000 OPERATING THIS REPORT IS SUBMITTED PUR SUANT To THE REQUIREMENTS OF 10 CFR B: (Check one o r more) (11)

MODE (9) 20.2201(b) 20.2203(a) (2) (v) 50.73(a)(2)(i) 50.73(a) (2) (viii)

POWER 20.2203(a) (1) 20.2203(a)(3) (i) 50.73(a)(2)(ii) 50.73(a) (2)(x)

LEVEL (10) 1 00% 20.2203(a) (2) (i) 20.2203(a) (3)(ii) 50.73(a)(2)(iii) 73.71 20.2203(a)(2) (ii) 20.2203(a) (4) 50.73(a) (2) (iv) OTHER.

20.2203(a) (2) (iii) 50.36(c) (1) 50.73(a) (2) (v) SpecHy In Abstract below or in NAC Form 366A 20.2203(a) (2) (iv) 50.36(c)(2) 50.73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12)

TELEPHONE NUMBER (IneIude Ares Code)

Michael Verrilli Sr. Analyst - Licensing (9191 362-2303 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE REPORTABLE REPORTABLE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO NPROS TO NPROS SUPPLEMENTAL REPORT EXPECTED (14) MONTH OAY YEAR EXPECTED YES SUBMISSION X (If yes, complete EXPECTED SUBMISSION DATE). No DATE (15) 6 30 98 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewrinon lines) (16)

Qn March 13, 1998, with the plant operating at 100% power in Mode 1, a design deficiency related to potential runout of the Turbine Driven Auxiliary Feedwater Pump (TDAFWP) was identified and determined to be reportable as operation outside the design basis of the plant, Specifically, a scenario exists during a main steam line break accident or main feed line break accident where the TDAFW pump could potentially operate at runout for a design maximum of 41 seconds and result in pump failure. The Harris Nuclear Plant (HNP) Final Safety Analysis Report (FSAR) states that the TDAFW pump will be available to mitigate the consequences of these postulated accidents. This condition was reported to the NRC via the emergency notification system per 10CFR50.72 on March 13, 1998 at 1155 hours0.0134 days <br />0.321 hours <br />0.00191 weeks <br />4.394775e-4 months <br />.

The cause of this condition is inadequate original AFW system design. The AFW system design did not consider the possibility of the scenario described in this LER and therefore, did not.include adequate runout protection for the TDAFW pump speed control mechanism.

Corrective actions included performing an immediate operability evaluation, which determined that the AFW system would remain capable of performing it's safety function following the loss of the TDAFW pump caused by runout. Additional Engineering analysis will be performed to determme the appropriate long-term solution.

A revision to this LER will be submitted upon completion, of this engineering analysis.

NRO ORM 364A US. NUCLEAR REGULATORY COMMISSION 16-9Q LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITT NAME II] OOCRET LER NUMBER IBI PAGE 13l SEOUENTIAL RenSIN NUMBER NUMBER Shearon Harris NUCIear Plant - Unit //1 50400 2 OF 3 98 - 004 - 00 TEXT Pf ufo oooooi nqw'eg ofo odcfrHoof ooofoo of fffIChno 34QI IITI EVENT DESCRIPTION:

On March 13, 1998, with the plant operating at 100% power in Mode 1, a design deficiency related to potential runout of the Turbine Driven Auxiliary Feedwater Pump (TDAFWP) was identified and determined to as operation outside the design basis of the plant. Specifically, a scenario exists during a main steam be'eportable line break (MSLB) or main feed line break (MFLB) accident where the TDAFWP could potentially operate at runout for a design maximum of 41 seconds and result in pump failure.

The TDAFWP is designed to be protected from runout by it's variable speed - differential pressure controller.

This differential pressure controller will control turbine speed between 2300 and 4100 rpm to maintain a 28 psig differential between the TDAFWP discharge pressure and the turbine steam inlet pressure. When Steam Generator (S/G) pressures are low, the main steam pressure at the turbine inlet drops and the pressure differential controller will demand a drop in turbine speed to decrease discharge head and maintain the set differential pressure. Therefore, TDAFWP discharge pressure will increase and decrease as S/G pressure increases and decreases respectively. The maximum design speed that the TDAFW speed controller will allow the turbine to operate is 4125 rpm. If a failure occurs in the speed controller system, a mechanical overspeed trip set at 125% of rated speed will trip the turbine by unlatching the trip and throttle valve and shutting off the steam supply.

During a MSLB or MFLB accident scenario, it appears that the speed controller will not prevent the TDAFWP from going into a runout condition. Both a MSLB and MFLB will initially depressurize all three S/G's. As the S/G's depressurize, the turbine speed controller will lower pump speed to maintain the required setpoint.

However, once the Main Steam Isolation Valves (MSIVs) close, steam will be isolated from the faulted S/G and the two intact S/G's re-pressurize causing turbine steam inlet pressure to follow the intact S/G pressures. AFW flow isolation will not automatically occur for a design maximum of 41 seconds after the MSIVs are closed and during this period the majority of AFW flow will follow the path of least resistance to the faulted S/G .

Therefore, the TDAFWP discharge pressure will remain at essentially zero (that of the faulted S/G) and the pump discharge pressure will fall below the steam inlet pressure. This will cause the turbine speed control system to go to maximum speed and place the pump in a runout condition. For a maximum of 41 seconds the pump will be turning at 4125 rpm and pumping unlimited flow at zero discharge pressure with no protection.

The HNP Final Safety Analysis Report (FSAR) does not specifically address this condition and states that the TDAFW pump will be available to mitigate the consequences of these postulated accidents.

This condition was reported to the NRC via the emergency notification system per 10CFR50.72 on March 13, 1998 at 1155 hours0.0134 days <br />0.321 hours <br />0.00191 weeks <br />4.394775e-4 months <br />.

NRG rORM 366A US. NUCLEAR REGULATORT COMMISSION I4.SS)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITT NAME 11) OOCRET LER NUMbER Ib) PAGE 0)

SEOUEHTML REVISION NUMBER KUMSER Shearon Harris Nuclear Plant Unit //1 50400 3 OF 3

~

98 - 004 - 00 TEXT Pl carr eeet i npwaf. oct mdtro'end ~ af iYRC hne 3SQI (Ill CAUSE:

The cause of this condition is inadequate original AFW system design. The AFW system design did not consider the possibility of the scenario described in this LER and therefore, did not include adequate runout protection for the TDAFW pump speed control mechanism.

SAFETY SIGNIFICANCE:

There were no actual safety consequences. This LER documents 'a potential failure scenario associated with the loss of the TDAFWP during a MSLB or MFLB accident.

The AFW system is designed and operated to include design margins and engineering margins of safety. The AFW system design is such that no initiating failure and assumed single failure will render all three AFW pumps and associated train unavailable in providing the necessary coolant flow to the S/Gs. With no specific runout protection, it is conservative to assume a consequential TDAFWP failure for a MSLB or MFLB accident as described in this LER. However, the consequential loss of the TDAFWP will not prevent the AFW system from performing it's design basis safety function of providing a flowrate of 400 gpm flow to the S/Gs. This is based on the continued availability of the remaining motor driven AFW pump.'REVIOUS SIMILAR EVENTS:

There have been no previous conditions identified or reported related to a potential TDAFWP runout and consequential failure during a MSLB or MFLB accident scenario.

CORRECTIVE ACTIONS COMPLETED:

1. An operability evaluation (ESR 98-00100) was completed on March 13, 1998, which determined that the AFW system would remain capable of performing it's safety function following the loss of the TDAFW pump caused by runout.

CORRECTIVE ACTIONS PLANNED:

1. Additional Engineering analysis will be performed to determine the appropriate long-term solution for the potential TDAFWP runout condition and consequential pump failure. A supplement to this LER will be issued to the NRC upon completion of this analysis.