ML18004B925

LER 87-047-00:on 870804-05,auxiliary Feedwater Actuations Occurred Due to Trips of Main Feedwater Pump 1A.Caused by Discharge Pressure Switches Out of Calibr.Discharge Pressure Switches recalibr.W/870904 Ltr

ML18004B925
Person / Time
Site:	Harris
Issue date:	09/04/1987
From:	Schwabenbauer, Watson R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
HO-870493-(O), LER-87-047, LER-87-47, NUDOCS 8709100310
Download: ML18004B925 (10)

Text

REGU~~ INFORMATION DISTRIBUT ~TEM (BIDS>

ACCESSION NBR: 8709100310 DOC. DATE: 87/OV/04 NOTARIZED: NQ DOCKET FACIL: 50-400 Shearon Harr is Nuclear Power PlantJ Unit 1J Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION SCHWABENBAUER Carolina Poeer 5 Light Co.

WATSON> R. A. Car ol ina Power 5 Light Co.

RECIP. NAME RECIPIENT AFFILIATION

SUBJECT:

LER 87-047-00: on 870804-05J auxiliary feedujater actuations occurred due to trips of main feedea'ter pump 1A. Caused bg discharge pressure seitches out of calibr. Discharge pressure seitches recalibr. W/870904 DISTRIBUTION CODE: IE22D CDPIES RECEIVED: LTR itr.

TITLE: 50. 73 Licensee Event Report (LER) Incident RptJ J j ENCL j SIZE:

etc.

5 NOTES: Ap p 1 i cat i on f or p ermi t reneuja 1 filed. 05000400 RECIPIENT COP IES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 L* 1 1 PD2-1 PD 1 1 BUCKLEYJ B 1 INTERNAL: ACRS MICKELSQN 1 1 ACRS MOELLER 2 2 AEQD/DOA 1 1 AEOD/DSP/NAS 1 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB f f DEDRQ 1 1 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 1 NRR/DEST/ELB 1 NRR/DEST/lCSB 1 NRR/DEST/MEB 1 NRR/DEST/MTB 1 1 NRR/DEST/PSB 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 NRR/DLPG/GAB 1 1 NRR/DOEA/EAB 1 1 NRR/DREP/RAB 1 1 N RZDREP/RPB 2 2 NRR/PMAS/ ILRB 1 1 EQ F~ 02 1 1 RES DEPY GI 1 1 RES ELFORDJ J 1 1 RES/DE/EIB 1

, RGN2 FILE 01 1 1 EXTERNAL: EGG.G GROHJ M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRISJ J 1 1 NSIC MAYSJ G 1 1 TOTAL NUMBER OF CQP IES REQUIRED: LTTR 43 ENCL 42

Iv hA I I . e ~ 4404?k r4<kAv a ~

NRC Form 366

~0 US. NUCLEAR REOULATORY COMMISSION (9.63)

APPAOVED OMB NO. 31500104 EXPIRES: 5/31/65 LICENSEE EVENT REPORT (LER)

FACILITYNAME (I) DOCKET NUMBER (2) PA E 3 SH S N CLEAR P 0 5 0 0 0 1 OF AUXILIARY FEEDWATER ACTUATION.DUE TO MAIN FEEDWATER PUMP lA. TRIPS CAUSED BY DISCHARGE PRESSURE SWITCHES BEING 0 F EVENT DATE IS) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (SI

SEOUENTIAL REVISK?N FACILITYNAMES DOCKET NUMBER(SI MONTH DAY YEAR YEAR  !?Wc: NUMBER '?~c6 NUMBER MONTH DAY YEAR 0 5 0 0 0 0 8 0 5 8 7 8 7 0 4 7 0 0 0 9 04 87 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T 0 THE REDUIREMENTB QF 10 cFR (): /check one or more of the follovy/nP/ (11)

OPERATINO MODE (9) 20.405(c) 60,73(e) (2) (lr) 73.71(B)

POWER 20.405( ~ )(1)(l) 50.36(c) (1) 50.734)(2)(v) 73.71(c)

LEVEL oo) c>Wp'0.402(B) 00 0 20,405(el(II(ill 50.36(c) (2) 50.73(e) (2) (rll) OTHER /SPeclfy /n Ahttrect tN/owend fn Text A'RC Fo' 20.405( ~ I (1)(ill) 50.73(e)(2) I I) 50.73(e) (2) (vill)(A) 366A/

20 405( ~ )(1)(ivt 50.73(e) (2) (li) 50.73( ~ ) (2)(vill)(B)

Rv '~R?~ 20,405(e)(1)(v) 50.73(e) (2) (III) 50.73(e) (2)(x)

LICENSEE CONTACT FOR THIS LER 02I NAME TELEPHONE NUMBER AREA CODE R. Schwabenbauer Regulatory Compliance , -26 9 193 62 69 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFAC.

TVAER y h

'('AUSE SYSTEM COMPONENT MANUFAC.

TVRER EPOATABLE TO NPRDS 4M':

B S J PI SM 35 x r?trCr 1m Nck@

%oxno.'NN SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SU 5 MISSION DATE (I BI YES llfyn, complete EXPECTED SUBhll$$ /O/Y DATE/

x NO ABsTRAcT /L/mlt to /cot)epecet, le., epproolmnely fifteen tlnple.opere typnvritten linn/ (16)

ABSTRACT:

The plant was in Mode 3, Hot Standby, at 0 percent reactor power on August 5, 1987. During the period of August 4, 1987 at 2344 hours0.0271 days <br />0.651 hours <br />0.00388 weeks <br />8.91892e-4 months <br /> and August 5, 1987 at 0212 hours0.00245 days <br />0.0589 hours <br />3.505291e-4 weeks <br />8.0666e-5 months <br />, there were four Auxiliary Feedwater (AFW) actuations due to trips of Main Feedwater (MFW) Pump 1A on high discharge pressure.

A work ticket was issued for Instrument and Control (I&C) technicians to check the setpoints of the pressure switches on the discharge of MFW pump 1A. Three out of the four pressure switches were found to be out of calibration; they had drifted to a lower setpoint. The fourth pressure switch was within acceptable tolerance. The pressure switches were recalibrated and MFW pump 1A started at 1328hours and ran normally.

Action to prevent recurrence is that design changes are being prepared for the Feedwater and Condensate Systems which will reduce the discharge pressure of

+ID O the Main Feedwater Pumps and provide margin between operating conditions and OC equipment trip setpoints'he actuation logic for the Auxiliary Feedwater P)H System will be reviewed to determine if the actuation on a Main Feedwater Pump QIC trip can be reduced.

r O(3.'v mo.lA R This event is reportable under 10CFR50.73(a)(2)(iv) as an actuation of an Engineered Safety Feature (Auxiliary Feedwater System).

NRC Form 365 IB.IL1l

~0 l

NRC Form 388A US. NUCLEAR REGULATORY COMMISSION (34)3)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150-0104 EXPIRES: 8/31/88 FACILITY NAME (I) DOCKET NUMBER (2) LER NUMBER (8) PAGE (3) ear SEOVENTIAL K% IIEVISION Shearon Harris Nuclear YEAR NVM crl '. r NVMBErl Power Plant Unit 1 0 5 0 0 0 4 0 0 87 0 47 00 0 2 OF 0 4 TEXT ///mero brooch />>//rko>>L Iree e/R/Oronc/HRC Form 3884'4/ I )7)

DESCRIPTION:

The plant was stable in .Mode 3, Hot Standby, at 0 percent reactor power on August 5, 1987. During the period of August 4, 1987 at 2344 hours0.0271 days <br />0.651 hours <br />0.00388 weeks <br />8.91892e-4 months <br /> and August 5, 1987 at 0212 hours0.00245 days <br />0.0589 hours <br />3.505291e-4 weeks <br />8.0666e-5 months <br />, there were four Auxiliary Feedwater (AFW)

(EIIS:BA) actuations due to trips of Main Feedwater (MFW) Pump 1A (EIIS:SJ) on high discharge pressure.

At 2344 hours0.0271 days <br />0.651 hours <br />0.00388 weeks <br />8.91892e-4 months <br /> on August 4, 1987, MFW pump 1A was started to feed the Steam Generators (EIIS:SB), the pump tripped on high discharge pressure. This resulted in Auxiliary Feedwater (AFW) Pump 1B (EIIS:BA) to start, as required, to feed the steam generators. AFW pump lA was already in service at the time.

At 2356 hours0.0273 days <br />0.654 hours <br />0.0039 weeks <br />8.96458e-4 months <br />, another attempt was made to start MFW pump 1A; again it tripped on high discharge pressure. At 0005 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> on August 5, 1987, MFW pump 1B was started and the AFW pumps secured at 0017 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br />.

At 0156 hours0.00181 days <br />0.0433 hours <br />2.579365e-4 weeks <br />5.9358e-5 months <br />, it was decided to stop MFW pump 1B and try restarting MFW pump" lA. At 0201 hours0.00233 days <br />0.0558 hours <br />3.323413e-4 weeks <br />7.64805e-5 months <br />, an attempt was made to start MFW pump 1A with the discharge valves partially open instead of closed as required by pump logic.

MFW pump 1A tripped, which caused both motor driven AFW pumps to actuate, as required.

At 0212 hours0.00245 days <br />0.0589 hours <br />3.505291e-4 weeks <br />8.0666e-5 months <br />, with discharge valves on MFW pump 1A closed as required by pump logic, an attempt was made to start MFW pump 1A and again it tripped on high discharge pressure. At 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br />, MFW pump 1B was started and the AFW pumps were secured.

A work ticket was issued for Instrument and Control technicians to check the setpoints of the pressure switches (Mercoid Model gDAW-7043-804B-RG13E) on the discharge of MFW pump 1A. Three out of the four pressure switches were found to be out of calibration', they had drifted to a lower setpoint. The fourth pressure switch was within tolerance of its required setpoint. The MFW pump has four pressure switches installed on the pumps discharge line. The pump will trip if three out of the four pressure switches show a high discharge pressure. Since only one of the four pressure switches showed a low discharge pressure, MFW pump 1A tripped on high discharge pressure.

\

The pressure switches were recalibrated and MFW pump 1A was started at 1328 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.05304e-4 months <br /> and ran normally.

NRC FOII44 388A m U.S.GPO:1888.0424 838/488 (84)3)

NRC Form 366A UA. NUCLEAR REGULATORY COMMISSION T34)3)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150-0104 EXPIRES: 8/31/68 FACILITYNAME (1) DOCKET NUMBER (2) LER NUMBER (6) PACE (3)

Shearon Harris Nuclear YEAR @< SEQUENTIAL NUMBER ~P REVISION NUMSER Power Plant Unit 1 0 5 0 0 0 4 0 0 8 7 0 4 7 00 03 OF 0 4 TEXT /0'moro <<Mce /r Er)oker/, Irso a////Oon/I NRC Forrrr 3/IBAB/ (IT)

CAUSE:

It is concluded that= the drift of the discharge pressure switches is incidental to the event because the drift is very small with regard to the total setpoint.

The root cause of the MFW pump trip lies in the current design of the condensate and feedwater systems which produce very high MFW pump discharge pressures. As a result, when the pump is at minimum flow, small perturbations in system flow and pressure may inadvertently trip the pump. The minimum flow is maintained by a recirculation valve and it must respond to changes in flow demand from the steam generator flow control valves.

that the closure of a feedwater regulating valve can cause momentary pressure It has been calculated spikes of an additional 200 psig when the pump is run at minimum flow.

The high discharge pressure and recirculation flow control systems are the subject of ongoing design changes. These changes are also examining the need for protective and setpoint trips on the MFW pumps.

As a separate matter, there is no clear need to have an automatic AFW start on an MFW pump trip especially at no load. This trip is anticipatory in nature and is not safety-related. No credit is taken in accident analysis for this trip. Carolina Power (t Light (CP&L) is investigating the requirement to include this actuation signal. Manual operation of the AFW system is routinely expected at no-load conditions in lieu of the MFW pump.

ANALYSIS:

This event is reportable per 10CFR50.73(a)(2)(iv) as an automatic actuation of an Engineered Safety Feature (Auxiliary Feedwater System).

There were no safety consequences as a result of this event. The Auxiliary Feedwater System started as required upon loss of Main Feedwater to maintain water levels in the Steam Generators.

In this case, as the reactor was stable in Mode 3, Hot Standby, and at 0 percent power, the loss of Main Feedwater did not result in a plant trip.

This start is non-safety and anticipatory. The drift of the pressure switches was not severe enough to cause a trip of the MFW pump at full load conditions. If the drift had been more severe, it could have caused a MFW pump trip under normal operating conditions (i.e. not during minimum flow conditions). The worst case would occur at 100 percent power where the loss of one Main Feedwater Pump results in an automatic turbine runback with the potential for a reactor trip, due to low Steam .Generator water levels during the transient. A loss. of all MFW is an analyzed accident in the FSAR.

NRC FORM SSEA *U 8 QPO 1988 0 824 538/465 (94)3)

0 I(

hi IE

NRC Form 388A US. NUCLEAR REOULATORY COMMISSION I

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3ISOMI04 EXPIRES: 8/31/88

() FACILITYNAME Ill DOCKET NUMBER Ill LER NUMBER IBI PACE (3I SEOVENTIAL REvreloN Shearon Harris Nuclear YEAR gg NVM88R NVM88R Power Plant Unit 1 0 5 0 0 0 4 P P 8 7 0 4 7 00 04 OF 0. 4 TEXT (/more <<reoe lr reqokerf, rree ed$ Wonal HRC %%drm 33843 I ull ANALYSIS: (continued)

Previous Auxiliary Feedwater System Actuations at no load conditions have been reported in LER-87-026-00, where low lube oil pressure tripped Condensate Booster Pump 1A. LER-87"046-00, where a loose linkage on a MFW recirculation valve caused a pump trip which initiated an AFW actuation.

Corrective Action'.

The discharge pressure switches for Main Feedwater pump lA have been recalibrated to the correct setpoints.

Action to Prevent Recurrence'.

1) Design changes are being prepared for the Feedwater and Condensate Systems which will reduce the discharge pressure of the Main Feedwater Pumps and provide margin between operating conditions and equipment trip setpoints.

2) The actuation logic for the Auxiliary Feedwater System will be reviewed to determine if the actuation on a Main Feedwater Pump trip can be reduced.

NRC FORM 388A *U,B.OPO.'1988.0 824 838/488 ~

I983)

~ l gPg Carolina Power & Light Company HARRIS NUCLEAR PROJECT P.O. Box 165 New Hill, NC 27562 P0~ 19el File Nuittber'SHF/10-13510C Letter Number'HO-870493 (0)

U.S. Nuclear Regulatory Commission ATTN: NRC Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO. 50-400 LICENSE NO. NPF-63 LICENSEE EVENT REPORT 87-047-00 Gentlemen:

In accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted. This report fulfills the requirement for a written report within thirty (30) days of a reportable occurrence and is in accordance with the format set forth in NUREG-1022, September, 1983.

Very truly yours,

~ Harris R. A. Watson Vice President Nuclear Project RAW:skm Enclosure cc: Dr. J. Nelson Grace (NRC RII)

Mr. B. Buckley (NRR)

Mr. G. Maxwell (NRC SHNPP)

MEM/HO-8704930/PAGE 1/OS1