ML17347A969

LER 89-002-00:on 890116,normal Plant Cooldown Initiated Due to Small Boundary Leak of Rcs.Caused by Transgranular Stress Corrosion Cracking in Mapping Sys Thimble Guide Tube J-12 & J-7.Guide Tubes Involved Repaired or replaced.W/890214 Ltr

ML17347A969
Person / Time
Site:	Turkey Point
Issue date:	02/14/1989
From:	Conway W, Lyons E FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-89-50, LER-89-002, NUDOCS 8902220046
Download: ML17347A969 (10)

Text

gCCELEMTED DlSJBl.TlON DEMONSTR+10N SY> TE>>>

v REGULATORY INFORMATION DISTRIBUTION SYSTEM (RZDS) 1 DEACCESSION NBR:8902220046 DOC.DATE: 89/02/14 NOTARIZED: NO DOCKET g FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 05000250 AUTH. NAME AUTHOR AFFILIATION LYONS,E. Florida Power & Light Co.

CONWAY,W.'F. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 89-002-00:on 890116,reactor cooldown required by TS due to small unisolable leak of RCS at seal table.

W/8 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ZD CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 EDISON,G 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER D

2 2 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADE 8H 1 1 NRR/DEST/ADS 7E 1 0 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 1 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/QAB 10 1 1 NRR/DOEA/EAB 11 1 1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 2 2 ~NRR/ TS/ IB 9A 1 1 NUDOCS-ABSTRACT 1 1 02 1 1 RES/DSIR/EIB 1 1 RES/DSR/PRAB 1 1 RGN2 FILE 01 1 1 R EXTERNAL: EG&G WILLIAMS,S 4 4 FORD BLDG HOY,A 1 1 I H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS,J 1 1 NSZC MAYS,G 1 1 NZE 'IO ALL "RIDS" RECIPZEÃIS:

PIZASE HELP US IO REXXJCE WASTE! CXNI'ACr 'IHE DOCUK&l'XÃZ5QLDESK, ROOM Pl-37 (EXT. 20079) TO EIZtGZLTE KSR NAME FKH DISTK03UTIGN LISTS FOR DOCUMEXIS YOU DON'T NEED)

TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

"I 4

NRC Form 355 U.S. NUCLEAR REGULATORY COMMISSION (9 53)

APPAOVED OMS NO. 3)9)4104 LICENSEE EVENT REPORT (LER) EXPIRES: 5/31/CS FACILITY NAME (II DOCKET NUMSEA LT) PA Turkey Point Unit 3 () 5 0 0 0 5 0 ] pF 0

""'"'Reactor Cooldown Required y ec naca peel >ca sons ue o Unisolable Leak of Reactor Coolant System at Seal Table EVENT DATE IS> LER NUMSER IS) REPORT DATE (7) OTHER FACILITIES INVOLVED (5)

MONTH OAY YEAR CCQUCNTIAL ri c v Iororr OAY YEAR FACILtrr NAMES DOCKET NUMBER(SI YEAR NUMCCil fr UM4 C rr MONTH Turkey Point Unit 4 0 5 0 0 0 2 5 0 1 16 89 0 0 2 0 2 14 8 9 0 5 0 0 0 THIS REPORT IS SUSMI'TTED PURSUANT T0 THE R EOUIREM EATS OF 10 cFR (): Icntcl one or more ol tne foriowinof l11)

OPERATINO MOOS ( ~ I 20.402(4 I 20.405( ~ I 50.73(cl(2) INI 73.71(III POWER 20.405( ~ )(Ill)I 50.35(cl(1) 50.73(c) (2)(r) 73.7)(c)

LEYEL 0 0 0 20.405(c)(IIISI 50.35(cl(2) 50.73(e) (2)(r4) OTHER ISpecify ln Aprtiect priow emf in Tert. Hl)C Form 20.405(el(1) (i4) 50.73(el(2)(il 50.73(ell2)(r4))(AI 3554) 20.405(cl(1)(ir) 50.73(c I (2) I 4) 50.73(cl (2l (r)4) l ~ I 20.405 (el(I I (r) 50.73(ell2) ()4) 50.73(el(2)(cl LICEIISEE CONTACT FOR THIS LER l12l NAME TELEPHONE NVMSEA AAEA CODE Edward Lyons, Compliance Engineer 0 5 2 6 - 6 7 3 1 COMPLETE ONE LINE FOII EACH COMPONENT FAILUAE OESCRI ~ ED IN THIS REPORT (13)

MANVFAC. EPORTASLE COMPONEICT'ANUFAC EPORTASL CAUSE SYSTEM COMPONENT TURER 'TO NPROS CAUSE SYSTEM TURER TO iroAOS

"'"c."o ':1;/~AX A B TBG M120 SUPPLEMENTAL REPORT EXPECTED (14) MONTH OAY YEAR EXPECTED SUSMISSION DATE (I SI YES llfYM. compirto EXPECTED SVSCIISSIOfl OA TEI NO ASSTRACT ILimit ro 1400 rpecer, I.e.. eppfornmeteiy fifteen rincierpecr typewrinen finer) (14)

On January 16, 1989, at 1915, with Unit 3 in Hot Standby (mode 3, 547F,

"'325 psig) and Unit 4 defueled, a normal cooldown of Unit 3 was initiated due to a small pressure boundary leak of the Reactor Coolant System (RCS).

The leak was identified while performing an overpressure leak test of the RCS. The leak (approximately 12 drops per minute) was emanating from a crack in the flux mapping system thimble guide tube J-12. In addition, weepage was evident from guide tube J-7 ands and from the high pressure seal at E-5. Unit 3 reached cold shutdown at 1050 on January 17, 1989. Liquid penetrant (PT) examination was performed on all of the guide tubes above the seal table for both Unit 3 and 4. These examinations identified several other indications . All of the guide tubes with unacceptable indications have been repaired or replaced. Two'uide tube segments that were replaced were sent to an offsite materials laboratory. Based on the evaluations performed, it was concluded that the two cracks in those guide tubes were caused by transgranular stress corrosion cracking . The defects

,initiated from the outer surface of the tubes. FPL will reinspect the Unit 3 and 4 guide tubes using PT. This reinspection will be performed for Unit 3 during its next refueling outage and for Unit 4 during its next refueling outage .

220046 877()214 F DR ADOCI 0~00()z v NRC Form 355 F'DC~

(9 53 I

NRC FoIIII 388A U.S. NUCLEAR REGULATORY COMMISSION (NI3 I LICENSEE Ei T REPORT (LER) TEXT CONTINUAT N APPROVED OMS NO, 3I SOW!OS EXPIRESI 8/31/88 FACILITY NAME III DOCRET NUMSER l2l PAGE IS)

LER NUMBER (Sl SEGUENTIAL Turkey Point Unit 3 YEAR NUMSER REVISION NUMSER o s o o o 2 5 8 9 002 0 0 0 2 OF 0 4 TEXT /I/ ms/s spsss is /PEI/dsd, IISs sdd/ddIN///RC Form 38/IA's/ Ill)

DESCRIPTION OF THE EVENT On January 16, 1989, at 1915, with Unit 3 in Hot Standby (mode 3, 547F, 2325 psig), a normal cooldown of Unit 3 was initiated due to a small pressure boundary leak of the Reactor Coolant System (RCS) (EIIS: AB). At 1516 on January 16, 1989, a leak test of the RCS pressure boundry was commenced in accordance with procedure OP 1004.1, "Reactor Coolant System System Leak Test Following RCS Opening". At approximately 1648 the leak inspection team reported to the control room a leak of approximately 12 drops per minute at incore flux mapping system guide tube J-12. The leakage was emanating from a crack between the guillotine isolation valve and the Reactor Vessel, and was therefore, unisolable .

In addition, weepage was evident from guide tube J-7 and from the high pressure seal at E-5. Technical Specification 3.1.3.a states, "If reactor coolant leakage exists through a fault in the system boundary that cannot be isolated (ex.

vessels, piping, valve bodies) the reactor shall be shutdown, and cooldown to cold shutdown shall be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." At 1824 the Plant Supervisor Nuclear instructed the Reactor Control Operator to prepare for RCS cooldown. At 1915 a normal cooldown of the RCS was initiated in accordance with plant procedures. Unit 3 reached cold shutdown at 1050 on January 17, 1989 without further incident.

Following cooldown, all of the Unit 3 guide tubes above the seal table were inspected using liquid penetrant examination (PT). Indications were present in the following guide tubes: J-7, J-12, H-4, M-3, N-12. The weepage from E-5 was originating from a Swagelok fitting located above the guide tube.

Following examination of the Unit 3 guide tubes, the Unit 4 guide tubes were examined by PT. Guide tube conduit H-1 contained rounded indications similar to some of those in Unit 3.

CAUSE OF THE EVENT Metallurgical examinations were performed on sections of the J-7 and J-12 guide tubes. Based on the results of the evaluations performed, it is concluded that the cracks/indications in the guide tubes were caused by transgranular stress corrosion cracking. The defects initiated from the outer (OD) diameter surface of the tubes and most likely resulted from chloride contamination. The source of the presumed chloride contamination is not known at this time.

The cause of the weepage from the E-5 conduit fitting was not specifically identified.

ANALYSIS The amount of leakage from the guide tubes was very small and well within the capabilities of the normal makeup system. Unit 3 was cooled down in a normal manner without further incident. Based on this, the health and safety of the public was not affected .

NRC FORM 388A I94ISI

NAC Form 3ddA U.S, NUCLEAR AFGULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPAOVEO OMB NO. 3150WIOO EXPIRES: B/31/EB FACILITY NAME uI OOCKET NUMBEA I?I PAGE I31 LER NUMBER Id)

YEAR $ E Q I/E N T I A L REVISION NI/MSE4 NVMSS4 Turkey Point Unit 3 o 5 o o o 2 5 0 002 0 0 3 OF 0 4 TEXT I/Imari ssrooeis nqukrd. Irse sr/I//oorrs//r//IC Famr 3SBA'>> >

Following Unit 3 cooldown, the affected sections of the leaking guide tubes J-7 and J-12 were removed and sent to an offsite materials laboratory for evaluation. Based on the results of the evaluations it was concluded that indications on the guide tubes were caused by transgranular stress corrosion cracking. ,The defects initiated from the OD surface of the tube and most likely resulted from chloride contamination. Since maintenance activities are performed frequently above the seal table but not below the seal, table, it is believed that the presumed chloride contamination is limited to above the seal table . The evaluations performed also indicated that detection of the defects can be accomplished using PT examinations.

CORRECTIVE ACTIONS

1) Unit 3 was cooled down, and all of the guide tubes were examined by PT.

These examinations revealed five guide tubes with unacceptable indications on the tube.

2) A plant modification was performed to replace the affected sections of guide tubes J-7 and J-12.

3) The indications on guide tubes H-4, M-3 and N-12 were removed with a burr or hand file . Following removal of the indications, wall thickness verifications were performed on the tubes. The areas were then examined by PT to ensure the indications were completely removed .

4) The Swagelok fitting at E-5 was disassembled and reworked. The fitting exhibited no leakage when returned to service.

5) The Unit 3 guide tubes were verified to be leak free at full pressure .

6) The guide tubes above the seal table in Unit 4 were examined by PT. The indications at location H-1 will be removed prior to Unit 4 entering mode 4.

7) Plant procedures require that the seal table area be visually inspected for leakage following an opening,and reclosing of the RCS. In addition, FPL will reinspect the guide tubes between the seal table and the high pressure fitting for Unit 3 and 4 using PT. This reinspection will be performed for Unit 4 during the next refueling outage for Unit 4, and for Unit 3 during the next refueling outage for Unit 3.

8) The guide tubes between the seal table and the high pressure fittings will be cleaned with an appropriate solvent to remove any residual chlorides on the guide tubes. This action will be completed prior to entering mode 4 for Unit 4 and during the next refueling outage for Unit 3.

r

9) FPL will attempt to identify the source of the presumed chloride contamination. Additional corrective actions to prevent recurrence will be taken, as appropriate, depending on the results obtained.

NAC FOAM SSSA I9BSI

IRC form 388A U.S, NUCLEAR REGULATORY COMMISSION 9.83)

LICENSEE E T REPORT (LER) TEXT CONTINUATI APPROVEO OMB NO. 3)50M)04 EXPIRES: 8/31/88 FACILITY NAME 11) DOCKET NUMBER )3) ).ER NUMBER )8) PACE 13) ferTO SEOVENTIAL ~i~o. REV/SION YEAR 44iR r/UMBER ff4) NUMBER Turkey Point Unit 3 o 5 o o o 2 5 0 9 002 0 0 04OF 4 TEXT lllmore e>>oe /4 rer/ulred, u>> edd/o'o/ro/ HRC %%drm 3SSA 9/ (17)

ADDITIONAL INFORMATION Although Turkey Poi'nt has had RCS leaks in the past, no LER s were identified that describe a similar event.

The guide tube material is ASTM A213, 304 SS, cold drawn and heat treated .

NRC FORM 388A (9 83)

'4

~,1

P.O. Bnx 14000, Juno Seach, FL 33408.0420 FEBRUARY. 1 4 $ 98.9 L-89-50 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 3 and 4 Docket Nos. 50-250 and 50-251 Reportable Event: 250-89-02 Date of Event: January 16, 1989 Reactor Cooldown Required by Technical Specifications due to Small Unisolable Leak of Reactor Coolant S stem at Seal Table The attached pursuant to Licensee Event.

the requirements notification of the subject event.

'f Report (LER) 10 CFR is being submitted 50.73 to provide Very truly yours, Pg~+//~~a Q V W. F. Conw Senior Vic President Nuclear WFC/RHF/cm Attachment cc: Malcolm L. Ernst, Acting Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant an FPL Group company