ML20148S040
| ML20148S040 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 01/07/1981 |
| From: | Hines E DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, EF2-49-876, NUDOCS 8102020520 | |
| Download: ML20148S040 (4) | |
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January 7, 1981 EF2-49,876 Mr. James C. Keppler, Director Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Final Koport ot 10CFR50.55(c) itee on Inadequate Pipe Clearance. (s35)
Dear Mr. Keppler:
On December 10, 1980, Detroit Edison's Mr. H.A. Walker, Supervisor -
Construction Quality Assurance, telephoned Mr. Richard Knop of SRC -
Region Ill to report on a problem with Inadequate Pipe Clearance in the drywell at the Fermi 2 site.
In reviewing drywell piping clearances for installation of insulation it was noted that inadequate clearance was provided in many instances for installation of the required insulation.
In reviewing the actual clearances, it was noted that in many cases adequate clearance may not have been provided for pipe expansion due to heating. This could cause physical damage to Quality Assurance Level I piping, as well as possible damage to other Quality Assurance Level I equipment in the drywell.
A preliminary analysis indicates that the probable cause of the problem was the failure to specify minimum piping clearances on engineering drawings and/or construction specifications. Detroit Edison Engineering has completed their investigation of the problem and the final report is attached.
Very truly yours, 7-EH/ MAW /cp Attachment cc:
Mr. Victor Stello, Jr., Director Of fice of Inspection and Enforcement Division of Reactor Inspection Programs U.S. Nuclear Regulatory Commission Washington, D.C.
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Mr. Bruce Little, Resident Inspector 3
U.S. Nuclear Regulatory Co= mission i
l Resident Inspectors Office 6450 North Dixie Highway ll [
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Newport, Michigan 48166
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o ENRICO FFRiI FO ER ptANT - U? TIT 2 DEFICIEEY RETORT TEADEDUATE CIE>RANCE AIUACENT TO DRWELL pIpItr; SYSTDG TO ACCCf40DATE pRIDICTED THEM*AL EXpANSIG1 AND VIBRATICN-INDUCD f0VEMD7PS INTFCOUCTICN In order to insure that damaging contact will not occur between Mjacent piping systes or between piping and other adjacent plant features due to trovement caused by thermal expansion, seismacally induced vibratico and operationally induced vibraticn, it is necessary to rmintain ranimun clearances between all closely spaced plant features. niis clearance re -
quirement was provided for during tre design phase of Femi 2's ' piping Systems by application of a "Desicn Cbjective" which provided a mani. um of three (3) incres of clearance betwcen the outer surface of each pipe (or its insulatico) and any adjacent plant features. While this c6jective was generally adhered to in design, it was not fonxilly established as a design requircrent, nor was it adcpted as a criterien to be maintained during ccnstruction.
Supplementing the mini:nrn clearance objectives stated above, is tre planned preocerational Vibration and Dmanic Effects Testing precran which is described, in detall, in Sections 3.9 ard 14.1 of the Feca 2 FSAR. This program has been develcped to verify the overall y_plidity of the various Piping Systma 'Ihenral EhT:ansion and Vibration /calytical Sttdies, ccr. ducted during che plant design phase. 'Ihis prccram u s not fonrulated, haever, to cover all piping systcms nor was it intended to provide assurance of adequate clearance between plant piping systems and adjacent features prior to initial system heat-up/ pre-operaticnal testing.
DESCRIFrTICN CF 'IME pCTTENTIAL DEFICTE?C(
Field cbservaticns of installed piping systens in the drywll revealed cases where QA IEvel I Piping Systems pass questicnably close to adjacent pipes or other adjacent plant features. Based upcn these cbservaticns, a detailed survey was made of all installed piping systems in the drywll to determine those cases where the potential for contact, during plant operaticn, existed. The criteria applied durin<- the survey, required tPe identificaticn of all cases where a minimum of three incMs of clearance was not available for a non-insulated pipe or six inches for an insulated pipe.
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4 Deficiency Feport Pacy3 2 Once the cases of clearance less than the specified arrount were identified, a sample of the more apparently serious problems was investigated by ccn-parisco of the actual available clearance to the trovtrient predicted by tre Piping System Stress Analysis. Based upon the results of the survey, cases where potential ccntact between the installed QA Level I Piping and adjacent plant features were identified, and it was ccncluded that in accordance with the rules of 10CFR50.55(e) (1) (iii), a potential reportable deficiency existed.
NUCIFAR RFTL'IEIURY CCtNISSICN NCfrIFICATICN In accordance with the mies of 10CFT150.55(e), Itcm 2, verbal notificaticn of the above descrited potential 6eficiency was provided to the NRC Region III Staff, by the Fernu 2 Project Quality Assurance Dtrector, on Decceter 10, 1980.
CFRECTIVE ACTICU
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For each identified 1ccation where the pipe to pip 2 or pipe to other adjacent
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feature clearance is less than three incrus for ncn-insulated piping, or six inclus for insulated piping, the pipir.g drawings are being rnarked-up with the magnitude and direction of tre predicted n:1xirum thenral plus scismic deflec-tion, as provided by the Piping Stress Analysis; plus a nurgin of 20% to account for uncertainties in that analysis. 'These marked drawings are then used to perform a field walk-dcun of each potential problem location to see whether ccntact could occur during operaticn.
If it is determined, based upcn the walk-dcwn, that ccntact will not occur, no further acticn is taken.
If, during the walk-dcun it is deternined tMt ccntact will occur, apprcpri-ate rrodificaticns to the piping and/or the other cbject, are initiated to solm the problem on a case. unique basis.
In acMiticn, a field ccnstmetion criteria docurent will te prercred and issued which will provide for trdinirrum spacings to be maintained between adjacent plant features, and/or to alert the field forces to seek specific engineering assist-ance in cases where m.inimum spacmgs cannot be treintained.
SAFET( IMPI.ICATIrUS OF 'INE DEFICIETY If Piping Systems thenral expansicn is harpered due to ccntact wir n other adjacent plant features, there is a prcbability that damgingly high loads can be developed in the pipe, its supports, the restraining feature or the building structure. Such loads tray cause pe:manent deformaticns in the piping and its supports and could result, in the worst case, in structural failures.
Similarly, if piping which is vibrating due to seismically induced or operaticn-ally induccd loadings, is penrutted to ecntact adjacent plant features during that vibrator,/ excitaticn period, there is a possibility that irrpactive damge and/or premature fatigue failures tray result.
'Ihe Piping Systems involved are in the final phases of constructicn; bcwever, none of thm have been hydttstatically tested, N-staned or turned over to the cwner for final acceptance or preoperaticnal testing. The walk-dcwn program
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described above is part of the routine pre-hydrostatic test check out, and is
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9 Deficiency Report Page 3 intended to identify any apparent discrepancies in the finally censtructed systems. nus activity will ecntinue ticugbut the systems ccnpleticn and turnover sequence.
Cmduct of tM walk-dcwn program, coupled with the analytical verification activities of the Preoperaticnal Vibration and Dynamic Effects Test Prcgra.,
provide a very high degree of confidence that these systems will not exper-ience significant service loadings which were not accounted for in the original design.
As a result of this confidence, it is concluded that situations which could result in piping. system damage, to a dcgree that could cmprcruse the health and safety of the public, will not occur during the preoperational test or comercial phases of plant operation.
Prepared by:
/'8'80 J. d. Casiglrd Principal Engineer i
Approved Ly:
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T. H. Dicksco, Director Project Design JHC/bp G
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