ML19329B031

Informs of Potential Safety Question Re Reactor Vessel Support Member Transient Load Capacities After Postulated Reactor Coolant Pipe Rupture Adjacent to Reactor Vessel. Requests Review of Support Sys Design Bases in 30 Days

ML19329B031
Person / Time
Site:	Davis Besse
Issue date:	11/21/1975
From:	Schwencer A Office of Nuclear Reactor Regulation
To:	Roe L TOLEDO EDISON CO.
References
NUDOCS 8001290743
Download: ML19329B031 (3)

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DIS'IRIBUTION: w/o encl.

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LWR 2-3 Rdg TIC VMoore Toledo Ediren Cercany RKlecker AT:'ti:

Fr. Icwell E. Fce MNilliams Vice Prec1 cent, Facilities LEngle revelcerent EGoulbourne Editen Plaza AC?.3 (16) w/l encl.

300 t'adisen Avenue ELD Toledo, Chic 43652 IE (3)

Centleren:

The purpcse cf this letter is to inferr ycu of a pctential refety cuestien which has been raised regarding the desien of reactcr pressure veccci currett systers fer pressurized water reacters (.Wc).

Cn May 7,1975 the !. C was inferred by a licensee that certain transient Icads T

en the reacter vessel suc;crt renters that wculd recult fren a nostulatec reacter ecolant pipe ructure irrediately adjacent te the reacter vescel bad been underestirated in their criginal desicn analvcec.

It is the NFC staff's cpinien that the cuestien related to the treatrent of transient loads in the desien of reacter verrel suppcrt systerc rcv renly to other I';R facilitiec, especially there fcr which the decien a alyces were cerferra:d ccre tire acc. re rave therefere initiated a svateratic review cf this retter to deternire hcw thece leccs were tc%cn inte acccunt en cther M fccilities, and what, if cny, ccrrective.mascurec rcy be reccired fcr specific facilitics.

~he results cf licenrce studiec re crted to dete irdicate tbct, althcuch the cargirs of rafety ray be lets thcn cricinally interded, the rereter vecrel currett syster would retain cufficient rtructural intecrity to ru pcrt the vessel ard that the ultirate concecuencer cf thir pcctulated accident which eculd af fect the ceneral r.ublic are nc werce than cricinally c:ated.

Fe have net ccapleted cur irdependent evaluaticn of these studies. Fewever, bared en the teruits of cur evaluatien cf thic cFencrecen to date cra in recceniticn cf the Icw pretability of the carticular pipe recture which eculd lecd te additieral transient leadc en the currert svrters, we ccrcle?c that centinued receter ccereticn ard centinued licensinc of fccilitier fcr crerttien are cccertable wnile we ccnduct our generic review.

Le recuest that ycu revicu the decicn Facer fcr tre reccter versel cu tcrt cystem fer ycur fccility(ies) to deterrine whet"cr the trcnsient loc (r described in the encicture were taken into ccccurt scorecriately in the Ferien.

Pleace fr.fer-er cf the rerultc cf veur review within 3f., davc.

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The attach.ent: to the enclosure are crovided to indicate the inferntien that eculd te needed, shculd we deterrice, en the basis of 1 cur revidw, that a reescessnent of the vessel cupport design is recuired.

Fe are centinuing to evaluate and review the methedc1 coy for calculating the suhecoled bicudewn Icads with the nuclear steam system supellers.

Ycu should centact your nuclecr stear system surplier fer infer.atien recardine there calculatiens if necessary to cc plete your revicw.

This recuest for ceneric infctratien wac appreved by CAO urfer a blenket clearance nu or E-18C225 (FCC72). This clearance expires July 21, 1977.

Sincerely, Gdif 7 -k...a ;,r A. Schwercer, Chief Licht Eater Feccters Erarch 2-3 Civisien of Feacter Licensinc Enclocure:

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Ccnald F. Etuser, Er The Clevelard Electric lile:-inating Cerc.iny F. C. Ecx 50C0, Fccm 610 Clevelard, Chio 44101 Cerald Charneff, Esq.

Shaw, Pittran, Fetts ard Trewbridce 910 17th Street, N.;.

Uashincten, D.C.

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