ML17348A969

LER 90-014-00:on 901107,crack Approx Three Inches Discovered in Coolant Water Flexible Hose Flange Weld.Caused by Mfg Defect.New Flexible Hose Assemblies Received & Installed on 4A & 4B EDGs.W/910701 Ltr

ML17348A969
Person / Time
Site:	Turkey Point
Issue date:	07/01/1991
From:	Plunkett T, Dawn Powell FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-91-084, L-91-84, LER-90-014-01, LER-90-14-1, NUDOCS 9107080092
Download: ML17348A969 (12)

Text

ACCELERATED DQTR18UTlON DEMONS 'lON SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

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ACCESSION NBR: 9107080092 DOC. DATE: 91/07/01 NOTARIZED: NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION POWELL,D.R. Florida Power & Light Co.

PLUNKETT,T.F. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION R

SUBJECT:

LER 90-014-00:on 901107,crack approx three inches discovered in coolant water flexible hose flange weld. Caused by mfg defect. New flexible hose assemblies received & installed on D 4A & 4B EDGs.W/910701 ltr.

DZSTRZBUTZON CODE: ZE22T COPZES RECEZVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER),

iIncident / Rpt,SZZE:etc.

ENCL NOTES RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 D AULUCK,R 1 1 INTERNAL: ACNW 2 2 AEOD/DOA AEOD/DS P/TPAB 1 1 AEOD/ROAB/DSP NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 NRR/DS~T- SPLBSDZ 1 1 NRR/DST/SRXB 8E RE FZLE 0~2 1 1 RES/DSIR/EIB RG ZLE 01 1 1 EXTERNAL EG&G BRYCE I J ~ H 3 3 L ST LOBBY WARD 1 1 NRC PDR NSIC POORE,W.

1 1 I NS C MURPHY I G ~ A 1 1 1 1 NUDOCS FULL TXT 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

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lO il P.O.'Box 029100,. Miami, Fl, 33102-9100 APL JUL 0 1 IS'I L-91-084 10 CFR 50..73 U.. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 90-014-00 Date of Event: November 7,. 1990 4 B Emergency Diesel Generator (DG) Cool'ing Water Flexible Hose Weld Crack Could Prevent DG'From Performing Intended Safet Function The attached voluntary Licensee Event Report 251-90-014-00 is being provided for information. purposes only following the guidance provided by NUREG 1022, Supplement 1, Item 19.1.

This LER is being submitted at this time because of interdepartmental discussions related to the potential generic i.'mplications of this event.,

Very truly yours, r1 T

/ I-.F.P/<<+t/

~ Plunkett kyQi~

Vice President Turkey Point Nuclear TFP/DPS/ds enclosures

.cc: Stewart D. Ebneter, Regional Administrator., Region II, USNRC, Senior Resident Inspector, USNRC, Turkey Point Plant 9107080092 910701 PDR ADOCK 05000251 PDR

/gS an FPL Group company

LICENSEE EVENT REPORT (LER)

DOCKET NUMBER (2) tACt (2)

FACILITT NAME (1)

TURKEY POINT UNIT 4 05000251 OF 4 4 B EMERGENCY DIESEL GENERATOR (DG) 'COOLING WATER FLEXIBLE HOSE WELD CRACK COULD PREVENT DG FROM PERFORMING INTENDED SAFETY FUNCTION RPT DATE (I) OTMER FACII ITIES INV. (0)

EVENT DATE (5) LER NUMBER (6)

SEO t DOCKET 6 (S)

MON YR NAME 90 90 014 00 07 01 91 OPERATI NC MODE'9) 10 CFR PONER LEVEL (10) 100 OTHER Voluntar (Specify in A)xitrxet belov xnd in text)

LICENSEE CONTACT FOR THIS LER (12)

David R. Powell, Superintendent of Licensing TELtPMONE NURSER 305-246-6559 COMPLETE ONE LINE FOR EACM COMPONENT FAILURE DESCRIEED IN TRIS REPORT (IS)

CAUSE STS TEN CAUSt B EK PSP X999 N EXPECTED SUttLEMENTAL REPORT EXPECTED (16) SURMISE ION DATE (1$ ) MONTH DAY YEAR (if yen'enplete EXPECTtD SUEMISSION DATt)

ABSTRACT (16)

This voluntary LER is being submitted following the guidance provided by, NUREG 1022, Supplement 1, Item 19.1.

On November 7, 1990, with both units operating at 100 percent power, a crack approximately three inches long was discovered in a coolant water flexible hose flange weld. The crack was found during installation of one of the four six inch flexible hoses in the new 4B Emergency Diesel Generator (EDG) coolant system. This inspection was being performed in preparation for part of phase acceptance testing prior to turnover to the plant. The two new EDGs 1'f 'the FPL are being installed as part of the Emergency Power Systems Enhancement Project (EPS) . The two new EDGs are scheduled for turnover to the plant in the summer of 1991. The cause of the weld crack was a manufacturing defect. -The wrong material was used in the flexible hose stub by the manufacturer. New flexible hose assemblies were received and installed on both the 4A and 4B EDGs. The new assemblies incorporate a design that does not require the wel'ds which cracked.

The existing flexible hoses were removed and returned to the vendor.

The new flexible cooling water hoses were successfully retested during the remaining EDG acceptance tests. FP&L Quality Assurance (QA) and Nuclear Engineering are reviewing the generic implications of this event to determine if additional corrective actions are necessary.

LICENSEE ENT REPORT (LER) TEXTCONTINUATION

/FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO ~

TURKEY POINT UNIT 4 05000251 90-014-00 02 or 04 I. EVENT DESCRIPTION This voluntary LER is being submitted following the guidance provided by NUREG 1022, Supplement 1, Item 19.1.

On November 7, 1990, with both units operating at 100 percent power, while preparing for Emergency Diesel Generator (EK) (EDG) acceptance tests, a crack approximately three inches long was discovered in a coolant water flexible hose flange weld. The crack was found during installation of one of four six inch flexible hoses in the new 4B Emergency Diesel Generator (EDG) coolant system. This inspection was being performed in preparation for part of phase 1 of the Florida Power and Light (FPL) acceptance testing before turnover to the plant. The two new EDGs are being installed as part of the Emergency Power Systems Enhancement Project (EPS). They are scheduled for turnover to the plant in the summer of 1991.

II. EVENT CAUSE'.

Immediate Cause The immediate cause, of this event was a crack in the weld connecting the flexible hose pipe stub (EK) (FCON) and the flange.

b. Immediate Cause The manufacturer of the flexible hoses was different from that specified on the drawing received from the vendor.

c. Root Cause The cause of this event was a manufacturing error. Two samples of the weld material from the defective flexible hose were analyzed for chemical composition by Florida Power and Light.

This analysis and subsequent discussions with the vendor, Morrison-Knudsen Company, Inc., determined that the wrong material had been used by the manufacturer in the flexible hose stub. The filler metal to be used for welds is determined by chemical compatibility and thermal expansion compatibility with the metals being welded. The metals being welded were different from those called for in the plans. Therefore, the weld filler material called for in the plans was no longer applicable. This metal incompatibility resulted in the crack formation and propagation.

III. EVENT SAFETY ANALYSIS The Emergency Diesel Generators are necessary to provide on-site power to required safety related loads during a loss of off-site power. An engineering evaluation of this event by FPL engineering concluded that the loss of engine coolant due to the leakage described above could eventually result in engine failure by engine overheating.

0 LICENSEE OIENT REPORT (LER) TEXTk)NTINUATION J FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

TURKEY POINT UNIT 4 05000251 90-014-00 03 oF 04 The defect was discovered and corrected prior to turn-over of the subject EDG to the plant. EDGs 3A and 3B have a different type of flexible hose that has not experienced this type of failure.

Pre-operational inspections and tests were developed to locate infantile problems similar to the crack. discussed above. The tests and inspection are performed before the, equipment can be declared operational. Both units 3 and 4 are defueled and EDGs 4A and 4B are not required to support any required equipment.

At the time of this event, with both units defueled, the spent fuel pool cooling was the only load requiring backup power availability.

EDGs 3A and 3B were inoperable due to the current Emergency Power Systems Enhancement Project and EDGs 4A and 4B were still undergoing pre-operational and acceptance testing. If off-site power had been lost to Turkey Point Nuclear Power Plant, at this time, the site had available at least two (non-safety) blackstart diesels, which could have been started and connected via a dedicated line to the emergency buses from the C bus in approximately 20 minutes. Thus, the health and safety of the public were not affected by this event.

IV. CORRECTIVE ACTIONS The defective flexible hose and one of the other three flexible hoses associated with the 4B EDG were returned to the vendor for analysis and replacement on January 30, 1991.

2. The vendor supplied a complete set of new flexible hose assemblies for both 4A and 4B EDGs. The new assemblies were manufactured by the company specified on the vendor drawings.

The new assemblies incorporate a design that uses a floating coupling. in place of the weld that cracked. The new flexible hoses were installed on both 4A and 4B EDGs. The old flexible hoses were removed and'eturned to the vendor.

3. The new flexible cooling water hoses were successfully retested during the remaining EDG acceptance tests (phase II testing).

4. The Turkey Point Independent Safety Engineering Group (ISEG) has independently reviewed documentation of this event and recommended further review of quality activities and possible generic implications. The final determination of further corrective actions by FP&L Quality Assurance (QA) and Nuclear Engineering is scheduled to be completed by July 31, 1991.

0 LTCENSEE ENT REPORT (LER) TEXTbNTZNUATXON

'i/FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

TURKEY POINT UNIT 4 05000251 90-014-00 04 or 04 V.. ADDITIONAL INFORMATION

1. Similar LERs:

Voluntary LER 251-90-012-00 issued March 15'991I also reported problems with the coolant water system on the new EDGs.

2 ~ Vendor/Manufacturer: I

,Florida. Power & Light Turkey Point EDGs 4A and 4B were assembled by Morrison-Knudsen Company, Inc. The diesel portion of the EDG was manufactured by the Electro-Motive Division of General Motors. The engine is a 20 cylinder, skid-mounted diesel. The engine model number is 20-645F4B. The fai;led flexible hose assembly was manufactured by Air Craft Metal Products. The replacement assembly and the one called for in the vendor drawings was manufactured by Flexonics.

The generator portion of the EDG was manufactured by NEI Peebles-Electric Products.

3. The vendor, Morrison-Knudsen Company, has .worked with FPL during this event.

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