ML20235B989
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6dEcket File DEC 13 $2.
PDR Local PDR RP Reading Doeket Be. 50-263 Branch Reading JRBuchanan, ORNL DJSkovholt, L:OR TJCarter, L:0R Eerthern States Power Company ACRS (16)
AITE: Ihr. Arthur V. me k.eg R0 (3)
Ties Presideae of y :_;;mg JGallo, OGC 414 Bise11st Mall DLZiemann, L:0RB #2 Minnespells, Mi=====ta 55401 JJShea, L:0RB #2 RWReid, L:0RB #2 Gentlemens RMDiggs, L:0RB #2 Further infe==*ia= is aser semilable to supplement the 31restorate of Regulatory Operatieas h 11mtim 72-1 shish infenned yes of the failure
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of several hangers that esyperted the emergener eere eseling system emeties header at the quad-eE*Waa 2 remeter.
n=*==* measurements at quad-Cities 1 and 2.and am1=1**i== performed by the 11eenses have use been reported to the ABC. The emase of the failure was detarstand to hos (1) facerrect mesumptiens of the static loads in the design of the hanger support syst;em; and (2) failere to esasider in the hanger system design the offect of # mmute leads, faciuding these resulting from operatima of the automatia puessera relief valves.
At quad-Citi$s 1 and 2, time meneered support system statie vertical hanger leads varied between 4 and 22.300 abe. h origiani design maximma lead for each henger was approximately 8000 lbs. h namoured everesa vertical hanger lead one appresimately 9400 lbs. The reasse for this diserapemey is not knesa at.this time; however, the ammeured E
vertimm1 leeds en the hungers were generally found to be the largest at leestions where the Smargeney Core emeling System (ECCS) peep suetten piping uns esenected to the sustian header.
M====remmets takaa en the susties header and rappression ehember during operattaa of the am*===*4= pressere relief valves have been maalysed and the results indiente that beamte 1meds imposed en the hangers during relief valve operatism also eseeed design mestamma leads. These dynamie leads were met eemaisered la the original hanger design er in the' design of the ampyr===4+= ahamber at this
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It is requested that yee provide this office with the following infor-nation relating to Monticello Unit 1:
1.
Provide a sesumary of a dynamie analysis of the torus ring header system subjected to blendswa forees resulting from aparation of the antenatis preneure relief valve.
T==1=Ae informatias em the 2,g r
mathematical model, estammt 26 of the system. and the V
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/ s, Northern States Power Company DEC 131972 2.
Provide the basis for determinaties of foreias foneties as derived from alther test data'er analytiani methods.
3.
Provide a sammary of (a) the stress analysis of the terms ring header erstam, imelading the interaction of cerus wali and henger sepperts under statia and dynamie leads, and (b) fatigue analysis of the ring header, hangere, and eeuponent parts that are edrjested to eyelis Imod during blowdown.
4.
In the event the above analysis deusestrates stresses in essess of eeds alleuable design values, provida your plans and schedmies for eerrective setians, and esafirmatory toets.
5.
Describa any previstems that may be available in the plant design whiek would allow "'m amargency eere and sentai====t emeling systems to fumetLA for less-term effectiveness in the event of failare of the emeties header.
If all of the reevented informaties is met surrently sveilable 'piesse supply within thirty days the armitahle information together with a descripties of yeer plans and schedule for warplying any missing infor-motian.
This inferusatten shonid be provided with ese signad eristaal and thirty-mine additimaal espies,.
Sinserely,
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Domaid J. Showbolt dseistent Director for Operating Roseters miresterste of Lie asing
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est Gerald Charnoff Shaw, Pittman, Potts, Trowbridge & Maddas 910 - 17th Street, N. W.
Washington, D. C.
20006 Enviremmental Library of Miameseta 4
1222 8. E. 4th Street I
Minneapolis, Mi - ta 55414
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