ML17209A657

Final Deficiency Rept Re Potentially Reportable Design Deficiency in Valves Mfg by Target Rock Corp,Initially Reported 801124.Target Rock Has Modified Valve Design to Eliminate Flow Induced Vibration

ML17209A657
Person / Time
Site:	Saint Lucie
Issue date:	01/26/1981
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, L-81-25, NUDOCS 8102250210
Download: ML17209A657 (7)

Text

REGULATORNPORMAT ION DISTRIBUTION STEM (RIBS)

ACCESSION NBR:8102250210. DOC ~ DATE: 81/01/26 NOTARIZED: NO DOCKET FACIL:50 389 St 9 Lucie PlantE Uni t 2E Florida Power 8 Light Co ~ 05000389 AUTH ~ NAME AUTHOR AFFILIATION UHRIGPR ~ E ~ Florida Power L Light Co, RECIP.NAB, RECIPIENT AFFILIATION 0 REILLYiJ ~ P ~ Region 2P Atlanta, Of f ice of the Director

SUBJECT:

Final deficiency rept re potentially reportable design deficiency in valves mfg by Target Rock Corpiinitially reported 801120 Target Rock has modified valve design to

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eliminate flow induced vibration ~

DISTRIBUTION CODE: B019S COPIES RECEIYED:LTR ~ENCL SIZE:

TITLE: Construction Deficiency Report (iOCFR50.55E)

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL ACTION: A/D LICENSNG 00 1 1 YOUNGBLOODgB 05 1 1 RUSHBROOKPM ~ 06 1 1 NERSESEV ~ 07 1 1 INTERNAL: AD/RCI/IE 17 1 ASLBP/J ~ HARD 1 1 D/DIR HUM FAC15 1 1 DIRE DIV OF LIC 1 1 EDO L STAFF 19 1 1 EQUIP QUAL BR11 1 1 HYD/GEO BR 22 1 1 I8E 09 '1 1 LIC QUAL BR 12 1 1 MPA 20 1 1 NRC PDR 02 1 1 OELD 21 1 1 PROC T T REV 13 1 1 QA BR 10 1 1 e.~ FIL 01 1 1 RUTHERFORD,lf, IE 1 1 21 1 1 EXTERNAL: ACRS 16 16 16 LPDR 03 1 1 NSIC 08 1 1 pF8 36 )99fl TOTAL NUMBER OF COPIES REQUIRED: LTTR 39 ENCL 39

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.O. BOX 529100, MIAMI, FL 33152 FLORIDA POWER I( LIGHT COMPANY January 26, 1981 L-81-25 Mr. James P. O'Reilly, Director, Region II Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303

Dear Mr. O'Reilly:

Re: St. Lucie Unit 2 Docket No. 50-389 Low Pressure Safety Injection System Valves Target Rock Valves - Design Deficiency 50.55 e On November- 24, 1980-, Florida Power 8t Light Company (FPL) notified the Office of Inspection and Enforcement, Region II of a potentially reportable design deficiency in several valves manufactured by the Target Rock Corporation.

On December 23, 1980 (L-80-414),. FPL submitted an interim response which stated that the subject deficiency was being evaluated and that a final report would be submitted by January 24, 1981. FPL has completed its evaluation, and a final report is attached for your review.

Very truly yours, Robert E. Uhrig Vice President Advanced Systems 8 Technology REU/TCG/ah Attachment, cc: Harold F. Reis,, Esquire,(w/o attachment)

Director. of Inspection and Enforcement.

U. S. Nuclear Regulatory Commission pot'f Washington, D. C. 20555 (w/attachment) gi(

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Final Design Deficiency Report Target Rock Valves

~Summa r A design deficiency was identified in valves manufactured by Target Rock Corporation and furnished by Combustion Engineering. Due to the design deficiency the valves, when operated under design conditions, would be prone to failure. The failure. would consist of the disc separating from the stem, cracks in the valve seat and backseat, and scoring of the disc below the seating surface.

In accordance with the requirements of 10 CFR 50.55(e), the above deficiency is considered reportable. By telephone FPL notified the NRC on November 24, 1980, and an interim report was submitted on December 23, 1980 (FPL Letter L-80-414). This final report is submitted to advise the NRC of the descrip-tion of the deficiency and the corrective actions that will be taken.

Descri tion Our NSSS vendor (Combustion Engineering) and Mr. C. R. McFarland (NRC) informed FPL that a. design deficiency had been identified in Target Rock valves (8" motor- operated globe valve) at the San Onofre Nuclear Generating Station (SONGS) and had been reported by Southern California Edison to the NRC under 10 CFR 50.55(e). An investigation concluded that St. Lucie Unit 2, globe valves HCV 3615, HCV 3625, HCV 3635, HCV 3645, V 3536, V 3539, V 3550, and V 3551 perform the same flow throttling service as the valves in the SONGS unit and are similar in design to the SONGS valves that failed, except that the,St.. Lucie valves are 6" (HCV 3615, HCV 3625, HCV 3635, HCV 3645), 4" (V 3536, V 3539) and'"'V 3550, V 3551) in size. The valve failure. at, SONGS has been attributed to excess flow induced vibration while the valve disc was in a partially open position. Cracks in the valve seat and backseat weld. a'nd scoring of the valve disc below. the seating surface would result from impact of the vibrating disc on the seat.

Corrective Action Target Rock Corporation has modified their valve design to eliminate flow induced vibration by providing a disc which is guided by the seat in the partially opened position., All affected 6", 4", and 3" valves cited above will be returned to the valve manufacturer for inspection, rework, modifica-tion and testing; Safet Im lication This deficiency could have adversely affected the safety of operations at the. plant during its 40 year life if it were to have remained uncorrected.

It represented a significant deviation from performance specifications which the component to perform its required repairs to establish the adequacy of

intended safety function. The affected val,ves are part of the Safety Injection System whose safety related function is to- insure that adequate flow is delivered to the Reactor Coolant System, thus insuring adequate core cooling.

Without the assurance of valve component integrity when subjected to the design basis service conditions, safety of plant operations could be jeopardized.

V. Conclusion Corrective action as indicated in Section III of this report will be under-,

taken by the, vendor to assure. that the valves are able to perform their intended safety function.

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