ML17037C467
| ML17037C467 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 09/25/1975 |
| From: | Lear G Office of Nuclear Reactor Regulation |
| To: | Rhode G Niagara Mohawk Power Corp |
| References | |
| Download: ML17037C467 (12) | |
Text
Docket Noi 50-220 DISTRIBUTION:
NRC PDR
$ EP 3 5
~975 Local PDR Docket ORB83 Rdg KRGoller TJCarter Niagara Mohawk Powor Corporation OELD ATTN:
Mr. Gerald K. Rhode Vice President - Engineering 300 Erie Boulevard Nest
- Syracuse, New York 13202 SVarga DEisenhut Gentlemen:
RE:
NING MILE POI1NT NUCLEAR STATION, UNIT 1 Gray file Your lotter dated July 31, 1975, referenced a report entitled, "hfark ACRS (161 I Containmont Status Roport", dated July 31, 1975, prepared by tho General Electric Company (GE).
Based on our review of tho GE status
- report, we find that wo nood additional information to complote our ovaluation.
The information required is listed in the onclosure.
For your information, a copy of the enclosure was sent by telecopy to Mr. T. Keenan, Yankee Atomic Electric Company (Mark I Owners Group coordinator) on Septembor 9, 1975, In addition, most of the concerns listod in tho enclosure have boon tho subject of discussions between the NRC staff and GE. It is anticipated that the responses to the enclosure will be presented in tho final report of the hark 1'hort term program scheduled to bo issued at the ond of September,
- 1975, with the exception of the two items noted as long term program items.
Please contact us if there is any additional information neoded rogarding our request.
This request for generic information was approved by GAO under a blanket clearance number B-'g,80225 (R0072); this clearance oxpiros July 31, 1977.
Sincerely, f5(
George Lear, Chief Operating Reactors Branch N3 Division of Reactor Licensing
Enclosure:
Request for Additional Information OPPICR~
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Niagara Mohawk Power Corporation CC:
Arvin E. Upton, Esquire
- LeBoeuf, Lamb, Leiby $ MacRae 1757 N Street, N.
W.
Washington, D. C.
20036 Anthony Z. Roisman, Esquire Berlin, Roisman 5 Kessler 1712 N Street, N.
W.
Washington, D. C.
20036 Dr. William Seymour, Staff Coordinator New York State Atomic Energy Council New York State Department of Commerce 112 State Street
- Albany, New York 12207 Oswego City Library 120 E. Second Street Oswego,.
New York 13126
"t IE
hfARK I CONTAIhlhlEhlT STATUS REPORT JUI,Y 31, 3975 STRUCTURAl. Lh,G1;;rERX>,G ur:SnoXS AXD PoslTloss l.
On Page 1 of the roport. a statement is made that "tho hlarl<
3: containmonts will maintain their function during the most probablc course of tho LOCA event or during S/R valve discharge".
The cia)ression "most pro'bablc course of LOCA event" should bo defined and justification should bc provided to substantiate the
'xclusion or reduction ili magllitudc 1f any of ilidividual or combined LOCA offocts if the "most probable course..." is loss
'evere than thc worst possible LOCA cvcnt.
Tho,bases for the exclusion of S/R valve discharge loads from thc.short term program have not been presented in tliis report.
Provi<lc a thoroiigh <liscussion of S/R v;ilvc discharge loads and address the fo3.lowing point.":
1) thc possibility of combining S/R valve'loads with ot)lc).
I-pool dyll'ililic lo,.ds,
)
I
'I I
2) thc possibility and structural consequences of thc S/R v;ilvc'l),sc))argo loads occurring near. thc cnd of a LOCA cvont after a r1so Xn pool temperature>
3) thc ncgativc prcssure-rcsistini capability of various structures clcsigncd primarily ior. positivo poo3 prcssure, including the li)icr plate of concrete hlarl; I containmonts, 4) tlio possibility og exciting the resonant frcqucncy of thc ovaling or brcathi))g modes, of the torus, or otliex dynamic modes of otlier structiircs within tho pool, S) during the life of the plants thc number of oscillations anticipated to occur.
above and boloii the elastic limit, i)ith a supporting low cycle and higii cycle fatigue analysis for affcctod structuros, an<1 (long term program item) 6)
the load-resisting capability of various structures when subjected to a
LOCA near the ond of the plant lifo after, numerous cycles of S/R valve discharge loads (long term prqgram item).
2.
The results and conclusions presented in items "a", "b" and "c at the top of Page 0 arc not substantiated in the ILcport.
Th mat)Lcmatical models and methods of an"-lysis for items "a" and "o" are briefly, discussed in the letter from G. L. Gyorey to R. )()accary dated Juno 26, 1975.
The structural capability of thc ring header and vent pipes after failure of the column assembly has not been provided in either report.
For all structural analyses referenced in the short term program provide the following:
.a.
a description of the mathematical model used in thc anal>sis including justification for the boundary conditions and a discussion of thc computation of rotational and translational spr3.ng,constants',
b.
a description of thc methods of analysis
- employed, including reference to cstablishcd computer codes, types of elements
- used, inclusion of shear dcformations, and non-lincariti'cs, a jLLstification f01 simplifying assumptions made in.tho anal>'scs,
. d.
tlute bases for inpLit load data
<<nd material properties, and 0 ~
a presentation of rosults and conclusions vi)Lic)i include l
1)
) occ)t3.0n and magn3.tLlde of cxccssivc strcsscs or dcformatlons for critical clcr>ents, a>>d 2) t)lc justlficat;Lon t)1 Lt sLLc)1 cxccss3vc strcsscs 4'ill not
~ 7.'csult in loss of function of the containment or, ot)7er sfacty-rel;(ted systems.
Include thc strain rate effects',
thc acccptablc ductility ratios, thc margins of safety, the degree of conservatism,
)717ysical tests, crack control, effects on lcaktightncss,
... Ctc.
3.
A discussion of the five basic groupings of ))ark I plants is presented
~
on Page 5 <<nd detailed in Table 1.
Describe thc bases'or selecting t))c'ypical p)ant from each group for an in depth anal>'scs.
FLL11 scale hard(i'are tests and strain rate material tests are referred to Mitl>in t)>c report.
Describe the tost procedure, detail simplifying assLlml)tlons p
corn)7:Lrc thc matcrlag Llscd f01'.
~ t)lc 'test 4'1th that. Llscd ln the plants, justif>'hc LLse of static tests for dyna)pic and cycl3,c loading phenomenon, and compare t)Lc tost results 4'1th static finite element analyses.
~
'n Page 12 and 13,- the fundamental frequency of the ring header assembly is specified as 20 IIZ, Provide the details nc proccdurcs of analysis
>>hich lead to thc establishment of thi" v,.luc.
Can higher modes of the ring header assembly, its component parts or other structures within
't)>c torus bc excited by pool dynamic loads?
Por. the do>>'ncomer lateral expected to result in the downcomer.-hcacler assembly by performing a low cyclo load analysos,.specify the number of c>clos inelastic behavior of any clement of thc and justify t)~e integrity of this assembly fatigue analysis.
Present diagrams which detail thc distribution of thc resultant do>>nward and upward forces on the toru
, presented on Pago 17.
In the analysis of torus supports the following should also be, considered:
seismic loads in combination>>'ith
<lead, live and pool dyriamic loacls; thc integrity o~ lateral bracing, diagonals, ctc.;
column buckling; <<nd the intcgrit>
of thc stiffening ring and column connections.
"Acceptable strain limits" arc referred to on I'agc 17.
I)cfinc: these limits'nd justify their usc for both stccl and reinforced concrete
- axial, shear and bonding deformations, The special considerations of subparagraph Is); 3131.2 of Subsection iX) of thc KS.'Ill 8 I) )'Y Code,Section III, res)'rict yiclciing to localized areas.
S)iccif> thoso po'ol dynmnic loads>>)erich produce only such local
)'icld.i,ng.
I In thc section cntitlcd "Screening Analysis" on 1'agc lS several ins ignif1 ant" loa<l s are listed.
Speci fy>>'hcthcr 01 not. an)'f those 3o ids cou3d occur in combination with thc pli,vnl) significant pool d)>>ainic loacls a>i<1, if so, what would bc their percentage contribution.
On Pago lS i statement is )nade that "Vent headers can handle fallback loads cvc>> if lateral columns arc assumed to buckle".
Provide a description of the analysis which 'technicall)'upports the above statement.
Include a discussion of the buckling analysis of these columns.
In addition, denionstratc that 'after thc potential failure of these colwnns duc to fallback loads, the remainclcr of thc I.OCA loads can still be rcsistecl.
In support of thc data presented on. thc scrccning analysis, provide justification and skctc)res for any element in which 'stresses exccccl thc clast.ic limit, in particular, the vacuum breakers ancl thc relief valve lino over the pool.
Specif>
the safet>
ancl seismic classification of these clcments and provide justification that the 'failure of thc element woulcl not. cause loss of either, the "containment, or thc emergency coro cooling system function.
13.
On Page 20,
- a. comparison of other plants to theIreference plant assumed a parabolic pressure time pulse with a peak of 1/ psi and a dur tion of 20 milliseconds.
Justify these values in.light of the apparent discrepancy.with data presented on Page 13.
14.
Provide justification for. the use of a dynamic load factor of 1.3 and a dynamic allowable stress increase factor of 1.4 as presented in the comparison of other plants to the reference plant, pages 20 and 23.
15.
Provide a discussion of the analysis of the vent pipe bellows assembly which demonstrates its integrity when subjected to large dcfor:nations perpendicular to its axis of primary expansion.
~ '
a.
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