ML18022A511

LER 87-021-00:on 870414,circulating Water Sys Flow to Main Condenser Restricted,Resulting in High Condensate Temps,Trip of Both Feedwater Trains & Manual Trip of Turbine & Reactor. Caused by Debris on Pump Suction screens.W/870512 Ltr

ML18022A511
Person / Time
Site:	Harris
Issue date:	05/12/1987
From:	Hudson O, Watson R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
HO-870425-(O), LER-87-021, LER-87-21, NUDOCS 8705180101
Download: ML18022A511 (7)

Text

REQUL RY INFORNATION DISTR IBUTI 'YBTEN (R IDB)

I ACCESSION NBR: 8705180101 DOC. DATE: 87/05/12 NOTARIZED: NO DOCKET ¹ FACIL: 50-400 Sheav on Harv is Nucleav Pouer Plant> Unit 1> Carolina 05000400 AUTH. MANE AUTHOR AFFILIATION HUDSON> O. N. Cav olina Power 5 Ligh+ Co.

WATSON> R. A. Cav olina Power 5 Ligh+ Co.

RECIP. NANE "

RECIPIENT AFFILIATION

SUBJECT:

LER 87-021-00: on 870414> circulating water sos flow to main condensev' estv icted v'esul ting in high condensate temps> +v'ip of both feedwatev'v ains 5 manual "tv ip of tuv'bine 5 v'eac+ov'.

Caused bg debris on pump sue+ion screens. W/870512 I tv'.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR g ENCL > SIZE:

TITLE: 50. 73 Licensee Event Report (LER) Incident Rpt> etc.

NOTES: Application for pev mit v enewal f iled. 05000400 REC IP I ENT COP I EB RECIPIENT CO~IES ID CODE/NAI'IE LTTR EI'CL ID CODE/NAI'IE LT TR El'C L PD2-1 LA 1 PD2-1 PD 1 BUCKLEY B 1 1 INTERNAL: ACRS NICHELSON 1 1 *CRB NOELLER 2 2 AEOD/DOA 1 1 AEOD/DSP/ROAB 2 2 AEOD/DBP/TPAB 1 1 DEDRO 1 1 NRR/DEBT/ADE 1 0 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 1 MRR/DEST/ELB 1 NRR/DEBT/ICSB 1 NRR/DEBT/NEB 1 1 NRR/DEBT/NTB 1 NRR/DEST/PSB 1 NRR/DEBT/RBB 1 MRR/DEST/SGB NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 NRR/DOEA/EAB NRR/DREP/EPB 1 1 NRR/DREP/RAB 1 NRR/DREP/RPB 2 2 N /ILRB 1 NRR/PMAS/PTSB 1 1 REG FILE 02 1 1 RES SPEIS> T 1 1 RQN2 FILE 01 1 EXTERNAL: EQhQ GROH N 5 5 H ST LOBBY WARD 1 LPDR 1 1 NRC PDR 1 1 NBIC HARRIS> J 1 NSIC NAYS> G 1 1 TOTAL NUNBER OF COPIES REQUIRED: LTl R 43 ENCL 41

NRC Form 355 UA. NUCLEAR REGULATORY COMMISSION 194)3)

APPROVED OMB NO. 31504(04 EXPIRES: 5/31/SS LICENSEE EVENT REPORT (LER)

FACILITY NAME (I) DOCKET NUMBER (2) PAGE 3 Shearon Harris, Unit 1 0 s 0 o o40 OioF04 TITLE (4)

Reactor Trip Loss of Feedwater; Cooling Tower Fill Material in Condenser EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (5)

MONTH SEQUENTIAL Rm DAY YEAR FACILITYNAMES DOCKET NUMBER(S)

DAY YEAR YEAR  ?@j NVMSER ?7:I NUMBER MONTH 0 5 0 0 o 04 14 878 7 0 2 1 051 2 8 7 0 5 0 0 0 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CF R (II ICheck one or more of tne fotforffnff (11)

MODE (0) 20.402(b) 20.405(c) 50.73(s) (2) llv) 73.7101)

SOM(c) (1) 73.71(c)

'5 POWER 20AOS(e)(1) (I) 50.73(e) (2) (v)

LEVEL uo) 20.405 (e) (I ) (4) S0.35(c) (2) 50.73(e) (2) (rll) OTHER ISpeclfy in Abstrsct 8 "7 below end In Text, NIIC Form

<" N" 20AOS(s) (I ) (ill) 50.73(e) (2) (rill)(A) BBBAI jpj$ 50.73(e ) (2) (I) 20AOS(s ) (I ) (lr) 50.73(e) (2) (II) 50.73(e) (2) (vill)(5) 20.405( ~ ) (I ) (v) 50.7 3(s) (2) (III) 50.73(e) (2) (s)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE

0. N. Hudson 0 la o COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

" @coal v COMPONENT MANVFAC. SYSTEM COMPONENT MANUFAG 'PORTABLE CAUSE SYSTEM TVRER CAUSE TURER TO NPRDS 4!% ".K~!

B~WN SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SUBMISSION DATE US)

YEs Iffym, complete ExpfcTED $ (IBEtlsslDN DATEI ABsTRAcT ILlmlt to fcoo speces, I e., epproxlmetefy fifteen slnpreepsce typewr/rten ffnNI (15)

On April 14, 1987, the Shearon Harris Nuclear Power Plant was operating in Mode 1 at approximately 87X reactor power. Around 1800, during the process of cleaning the circulating water pump suction screens, debris from the cooling tower basin entered the circulating water system and restricted flow to the main condenser. Condensate temperatures rose rapidly and led to a trip of both condensate pumps due to high condensate temperature. This resulted in the loss of both feedwater trains and, consequently, a manual trip of the turbine and reactor at 1830 on April 14. Following plant shutdown, all visible debris was removed from accessible areas. The plant was returned to service at approximately 1500 on April 15, 1987.

8705180101 870512 PDR ADOCK 05000000 8 PDR NRC Form 355 194)3)

UrL NUCLEAR REGULATOAY COMMISSION NRC Form 366A (983)

LICENSE EVENT REPORT (LER) TEXT CONTIN ATION APPROVED OMB NO. 3150-0104 EXPIRES: 8/31/88 FACILITYNAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR @%i SEOUENTIAI. i~oN REV/S/ON re: NUMSER T~>rd NUMSER

/cameo 0 5 0 0 0 OF TEXT <<>>co /4 /r//roo/t, rrro //I/or>>/HRC Arm 35549/ (IT)

DESCRIPTION OF EVENT On April 14, 1987, the Shearon Harris Nuclear Power Plant was operating in Mode 1 at approximately 87X power. All three circulating water pumps were in operation. Circulating water pump 'A'ad an elevated suction screen differential pressure, and a Work Request was issued at 1520 on April 14 to clean the pump screens.

The circulating water pumps have stationary vertical screens to keep debris from the cooling tower basin out of the pump intakes. Two suction screen positions (inner and outer) are available at each pump bay. The inservice screen is typically installed in the outer location (farthest from the pump). However, in this case, the screens were installed in the inner location. At approximately 1800 on April 14, work was in progress to clean the suction screens. The screens must be removed for cleaning. The affected pump was not shut down when the screen was removed because full circulating water flow was required. A spare screen had been installed in the outer position serving the southern bay of pump 'A'o start the cleaning process.

As the debris-laden inner screen was removed for cleaning, most of the trapped debris fell into the bay. The small trough attached to the bottom of the screen did not accommodate the large amount of material present. The fallen debris was immediately drawn into circulating water pump 'A'nd was pumped to the condenser.

At approximately 1825, condensate pump high temperature alarms were received in the Main Control Room. The operators then observed a condensate temperature rise from about 127 to 130'F within one minute. Condensate pump

'B'ubsequently tripped due to high condensate temperature at approximately 1829. This caused a loss of the 'B'eedwater train and initiated an automatic turbine runback and control rod insertion. Condensate pump due to high condensate temperature approximately 10 to 15 seconds

'A'ripped later. This caused a loss of the 'A'eedwater train and a loss of main feedwater flow. The reactor and turbine were manually tripped at 1830 due to the loss of both feedwater trains. A normal recovery from the trip ensued.

Auxiliary feedwater automatically started and was used to maintain steam generator levels until a feed system could be restored.

Following the plant shutdown, a debris removal effort was initiated. The condenser waterbox was entered for inspection and cleaning. The amount of debris removed was sufficient to cause significant flow reduction.

Concurrently, the circulating water pump suction screens were removed, cleaned, and reinstalled in the outer screen locations. Approximately 100 cu.

ft. of debris was removed from the condenser. The circulating water system waterbox was then was then restarted to flush material to the waterbox. The recleaned to remove as much residual debris as possible. Visible debris was removed from accessible areas of the cooling tower basin.

NRC FORM 366A

• U,S.GPO:1988% 824 538/455

$ 4)3)

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (94LT)

LICENS EVENT REPORT (LER) TEXT CONTIN ATION APPROVED OMB NO. 3(50&104 EXPIRES: 8/31/88 FACILITY NAME (1) DOCKET NUMBER (21 LER NUMBER (6) PAGE (3)

YEAR N j"=8< SEQUENTIAL /&i'EVISION NUMBER '.4C NUMBER Shearon Harris Unit 1 o s o o o 40 87 0 2 1 0 0 03 OFO 4 TEXT /SmrFF EPoco lr t)rl/rkFIL IIFF /I/o/oo/NRC Fonrr 38543/117)

DESCRIPTION OF EVENT (continued)

In addition, selected heat exchangers in the normal service water system were inspected for debris. No debris was found in the air compressor and about two handfuls of debris was removed from the Waste 'B'ntercooler, Processing Building nonessential services chilled water system chiller (WC-3) heat exchanger.

The plant was returned to service at approximately 1500 on April 15, 1987.

CAUSE An inspection of the cooling tower indicated that the debris was primarily plastic fill material used in the tower to facilitate cooling water distribution. The fill material is a corrugated plastic sheet. (See attached sketch.) The returning circulating water is distributed to the spray nozzles and spray headers by means of concrete flumes. Seals connecting various parts of the flumes had failed and the leaking water was impinging directly on the plastic fill material. This caused the fill into the cooling tower basin. This debris had collected on the circulating material to break up and fall water pump suction screens.

In addition, the inservice screens were in the wrong location (inner position), the Work Request for cleaning the screens did not specify sequential instructions for cleaning the screens, and screen cleaning procedures were not available. The large amount of material on the screens was below the water line and could not be seen until the screens were lifted. When the screens were lifted for cleaning, the debris fell into the bay and since there was no backup screen, the material was sucked into the running pump.

An engineering evaluation of the cooling tower conducted. The evaluation indicated that the damage to the cooling tower is fill material damage was approaching its limit, and significant additional expected. Tower performance is expected to be degraded; and a performance fill damage is not monitoring program for the cooling tower will quantify the available capacity of the tower.

The normal service water (NSW) system also takes suction from the cooling tower. However, the pumps use a separate intake from the cooling tower basin. The NSW pumps'ischarge is also equipped with a self-cleaning strainer. The NSW supplies water to the Turbine Building, Waste Processing Building, and is the normal supply to the emergency service water system. As stated above, small amounts of debris were found in components serviced by NSW. As a result, a program will be developed to monitor heat exchangers serviced by NSW and ESW.

NRC FORM SESA 4 U.B.GPO.1986 D624 538/455 (94)3)

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (94)3)

LICENS EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150-0104 EXPIRES: 8/31/68 FACILITYNAME I'l DOCKET NUMBER (2) LER NUMBER (6) PAGE 13) yEAR gg i@ SEQUENT/AL NUMBER '::

g@ REVISION NUMSErr Shearon Harris Unit 1 o s o o o 4 8 7 2 1 0 OF 0 4 TEXT /Hmao 4Poco JI /99rr)a/, INo /I/orro/HRC Form 3/F/AS) (17)

ANALYSIS This event is being reported in accordance with 10CFR50.73(a)(2)(iv) due to manual actuation of the Reactor Protection System.

There were no safety consequences as a result of this event. All systems functioned as required, and the plant was shut down safely.

CORRECTIVE ACTIONS In summary, the following corrective actions were taken or are planned.

1. Visible debris was removed from accessible areas.

2. The circulating water pump suction screens were placed in the outer screen locations.

3. Circulating water pump suction screen cleaning procedures have been developed and implemented.

4. The cooling tower was subsequently repaired in a May outage.

5. A program has been developed and implemented to monitor the performance of critical plant heat exchangers that are serviced by normal service water either via NSW or ESW.

O/RC FORM 366A *U.S.GPO:1986.0 624 538/455 (94)3)

WARt1 AIR WARi1 AIR OUTLET ttt t DRIFT ELININATOR SPRAY N022LE

.D HOT WATER PVC FILL o o a oo oo o o o

o ' o'o

~ COOLED WATER COOL AIR COOL AIR FALLS TO BASIN BELOW INLET 365 F T. DIAMETER NATURAL DRAFT COOL I NG TOWER

0 C~I Carolina Power 8 Light Company HARRIS NUCLEAR PROJECT P.O. Box 165 New Hill, NC 27562 NAY 32 1987 File Number. SHF/10-13510C Letter Number'HO-870425 (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 87-021"00 Gentlemen.'n 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, R. A. Watson Vice President Harris Nuclear Project RAW:skm Enclosure cc. 'Dr. J. Nelson Grace (NRC RII)

Mr. B. Buckley (NRR)

Mr. G. Maxwell (NRC SHNPP)

MEM/HO-8704250/PAGE 1/OS1