ML20128D984

Forwards Portions of Contribution to ACRS Rept,Which Discusses Mechanical Design of Reactor Internals, Recirculation Sys & Main Steam Piping

ML20128D984
Person / Time
Site:	Monticello
Issue date:	11/13/1969
From:	Dromerick A US ATOMIC ENERGY COMMISSION (AEC)
To:	Boyd R US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9212070439
Download: ML20128D984 (7)

Text

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Nov i 3 e68 j

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I R. s toyd, Assistant Director for Reacter Projects, DRL

THNJ

5. Levine, Assistant Director for Reactor Technelegy, DRL NONT! CELLO NUCLEAR GENERATING PLANT - DOCKET NO. 50-263 Enclosed are the portions of our contribution to the ACRS report for the subject plant which discuss the mechanical design of the reactor 1 1

internals, the recirculation system, and the main stean piping.

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i l A. W. Dromerick, Chief Containment 4 Component Technology RT-835A Branch

DRL

C6 CTS:JFK Division of Reactor Licensing

Enclosure:

l Portless of ACRS Report ec w/enet:

4 D. R. Muller, DRL

} D. B.=Vassallo, DRL K. Wichman, DRL M. B. Fairtile, DRL bec: S. Levine, DRL R. C. DeYoung, DRL A. W. Dromerick, DRL J. P. Knight, DRL DISTRIBUTION:

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i For the corbined loading due to steady stato conditions, nornal operatinn transients and the operatinn basin earthqurAc, the primary and secondary strest 4

lit.ito for the 11catico)1o internain are uithin the limits of section III of the ASMC 11011er and Prc.snuro Vesoc1 Code. Ut*. find these lir.its neceptable. '

i Undur doninn accident conditionn, uhich juclude the ceabined londa fron a recirculation line break or a steam line break plus the desinn banio carthquie, t the pritsary stror:ses in the internnis r,tructure are within the limits of the ASME Code Section III. For t.hnso conditions, the deficctionn of the fue.1 f

channola control rod houcings and core support structurn are nir.o limited -

I-I to assure control red operation and the pronorvt.tton of core cooling rometry.

The hinhest peak strecoco in the interun1s assenbly ar.d its supporting structure occur during the thernal transiento resultinn-f ron the D3A and subsequent start-up and operation of the ccernency core cooling systenn. Thornal strees analyses,  ;

includine, finite olenent modeling of critical areas, were ec:nducted for the f

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shroud at the point of hithnt predictnd irradiation, the baf fle plate which supporto the jet utmp diffusert,, the dif funcru, and the various ocided joints that conneet thcas comprnento. In com instances the calculnted upper bounds for the penk str dn rengcc renultinr, f ron these thermal strencen n11r.htly execed I

the ASIM !!ucicar '!carel Cod.: fatin,t'e linftn for 10 cyc3cs. In these instances a etmhinntion of cinetic r"ed pinstic annlynce ucre opulled to anourc thnt ntructurnt inten.rtty of thcne rnenborn till be r nintalued du' ins and af ter the postuintnd condi tionn ent' the.t distortions vill be lirited to assure thr2t core flooding reid cooliri;, cap 6111 ties vill nc.t be ir pcited.

On the bash ef our evaluntion, s:u nt> riced r;bove, un find that adequate rinrr, ins of & fety have been provided in the drmi[;n of the reactor internni otructures for the postuirted occident conditions.

Some of the etninleno steci cantints in the !!onticello jet ptmp annemblics ucro found to be cracked. The principal cause of this crachinn has been identified by GC ns r.urface carburization. All of the cracked cantinen have been replaced.

llovcver, some of the cantinen used still have a highly carburized t urf ace.

The trnusition picco castinen nou instclied ucre produced by a raodified canting prccenn which has been shown to prevent s:urface carburization. Follow-on inspections in accordence uith an fraprovad quality nssorance pror,rnm have shwn -

the uce cantinp to be free of crackn.

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3-1he collar ccstings were rept.ir(d by rachining off the as-cast surfaces to the depth (0.10 inch) necessnry to assure removal of the carburization. The remaining castings in the jet put.p userblics $t111 have the carburized as-cast surfaces in those arcos not nachined for other purposes such ns weld preparation or to form clamping surfcces. 'lhe appliennt states that the low stresscs in these castings during nornal oparation end the fracture toughness of the base natcrial (under the c:.rbutized shin) are edequate reasons t o have confidence in the ability of these components to function without ftdlure during the life of the plant.

He find, however, that the analyses and teste upon thich those conclusions are ,

based appear to be greatly oversimplified, b'c also find that there were obvious deficiencies in the quality assurance profram under uhlch the carburlzed castinne.

were made. Because of these deficiencien, the inadequacy of the evaluations perforred and the record of failure involving these components, we shall require additional inservice inspection of all castings nanufactured and inspected to the same requirements as those which failed, gCIRCtlLA110:: SYSTEM 1hc reactor recirculation systen is d signed to withstand normal loads of mechanical, hydraulic, and thermal origin, including all design transients, plus operational basis catthquate loads (OBE) within appropriate code allowable strer.ses.

For the combined loading case of the design basis earthouake (DBE) plus the desig.n basis accident, the primary stresses are also within the appropriate code limits.

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tecirculation pipinn v.u; darinned to the l'3AS D31.1 Prent.urc Piping Code, 1

Additional decirn and surrectica requirennnta vore taken from the AS."I Ilotler ned Pror.nurc Vesnel Cede Section I. The recirculation pino linco have nino been i

i provided with a syntem of pipe rent raintt, which are denir,ned to If nit the oipe

! notion which would occer in the event of cf ther a ciretoferential break or p lonnitudinal t.plit.

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• incto ration rent ritinth have been desirned to pernit the j

nerval and net.cscary pipe t-overenta dus to prnsure end thotnal expttnnion vithout

inducing additional ntreer,es.

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Valves in the recircult.tlen nynten ucro denf racd prinarfiv to the USAS B31.1 Prensure Pipinn Code. Where this code did not pr ovide ruidance, requiretaents were extracted f ron the ASMC Boilejr and Prennurn Vence] Code Section I.

i As in the enno of the najority of the BUR reactora now in operatica, the recir-culation pumps vero decinned to Section III of the ASMS Iloiler and Prensure 3

Veccol Code as Clace C vassals.

{ The cciopic analysis of the recirculation synten va4 perforned by the equivalent static coef ficient rnethod. A lunped naan tathenatical nodel uns uned to deterntne the periods of vibration and the t: ode shapon. Pesponse of the pipinn synten vos then deternined by crectral acceleration techniquen.

On the bacia of our review of the infornation at6taitted by the applicant, stemnrized i

above, ve find the desinn criteria and design linits for the recirculation systto acceptable. The uno of the equivalent otatic coef ficient nothod for the scisnic w- w am p n y g -v--~v,--r, rw-~- v-, nv- , -- y ,- , , , - - , - ,w y - ,. ,g em ----,--

g-yv y rs-~e--

y- rn---- - - n

analysis of this systen in puu ntly inder review by our dynarie deninn connult ant.

Our final acceptance of th ner. ten an inctalled is, therefore, dependent on our consultants deternination of the adequncy of the analytical techniques used to execute the desir;n.

ST Q 1 3 The nain nt ean piping frcm the reactor vmel to the turbi.no ven designed to the USAr, b31.1.0-1967 Code for Presourc Piping. The cpplicant ha stated hin intention to hydroctett cailly tect all piping in the royr4 ten to 1 1/4 tinen the deni gn pressure.

In addition to the banic design requirnnento inponed by the B33.3.0 Code, a scient e naalysis ut.s perfomed by the equivalent stntic coef fief rnt tmthod.

The strescos calculated by this nethod, vhen conbined with the nercosen eniculated to renuit f rom nornal operating loads, and OBE scinnic loads are cell within the code alicunbles. Similarly, the combined stresses fron operatinr, lords plua D3E scionic loads are voll vithin the yield strength of the pipina, rateriel.

We find the above design ctress limits acceptable. The details of applicction of the equivalent static coef ficient nna3ycia for= thic plant end cysten 19 nce undar reviou by our dynamic desir.n consultant. Our. final acceptnaco of thin desinn vill be held until the. analytical techniques enployed are found to be adequate.

In addition to any Code required inspections all circunferential butt velda tu this piping vill be 100 percent radionraphed, and all ciretmferential velds fron the reactor vessel to the second icolation valve will. also be inspected usinn l

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either nar,netic particle or liquid penet rnnt techniques. We find this innpection progran neceptabic.

V11m A*1 ? O3 C0170L The re netor intera:h. win u.clyxcd to detemine the enpnbility to withstand f1co induced vibratico. At thic tir e no vj$ ration i scen :etemotn are pinnned durinr, the r. tar tup ter;c imriod. In discurnint thir. t?.ncter the appliemt stateo that the GL vJbrction centrol pro. Orca for all pluit featuro vill be or hnt been adequateJy doment.t rat ed ca ctht r bun plca ts. bhilo uc ca,rce that a major vihrntion ter,t progrna in t.ot raewnnry for o plant of proven den $ tn, uc do not anroc with cny position whit.h could allou a large pour ' reactor to be epercted at nignificant poucr icvcIn prior to confirmtory vibrnt.lon tects. In t.ddi tion, ns of thin tirn- confiining data from vibration tenta r.t reference pinnts for !!onticello (Drendon 2, Oynter Creek and flino ' tile point-) have not been released to DRI.

for ovaluation. Un understond that thin delay in dua in part to the- f act that difff cultier, involving instrtracnt f ailures during the vibration mensurouent et some of the referenco plants _ have dcInyod the devalernant of infomntien noccanary to denenstrate the vibration characteristien of the EUR type reactor.

Un shall requirn, therefore, that the vibration Jevo3n of the critical internni F

and recirculation t.yntem conponento be nenitored durin ; the plant ctartup and initial operation pericd.

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