IR 05000255/1990017
| ML18057A676 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/29/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18057A675 | List: |
| References | |
| NUDOCS 9012310004 | |
| Download: ML18057A676 (7) | |
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- e UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVAL~lTIQ~_Qf_}~~.:f~h1~~£f~
CONTAINMENT.CONSTRUCTION OPENING AND RELATED
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ITEMS. FROM INSPECTIO~,.;EEPO~J. f~~/9001]
INTRODUCTION Cons~mers Power Company is in the process of replacing the two steam generators (SG) at ~hE: Palisades Nuclear. Plant.** The replacement is being accomplished by cuttirtg a tr*ansfer opening in the containment, followed by riggi11g * ~ach SG as a whole unit~ After the completion of the SG replacement, ~he opening will be closed and the*- containment will bt. restored to its original integrit *
Ccnsumers PO\\.,.er Co11:par1y is performing* the rt:plact:mtnt ur1der 10 CFR 50.59. The NRC staff ha~ tur;ducted in~rec't ions of the r*e lated 10 CFR 50. 59 facility change packages associattd ~ti th the SG replacement. This Safety Evaluation addresses op~n items from InspEctiori Report 255/9001 *
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QP~!1_} tern 90017-0i
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T~e following ~oncerns ~ere noted regarding rnodific~tioris to the Component Cooling Water (CCW) Surge Tahk*Rorim:
The Safety -E.v~luation (SE) dHI not address the poter1t,ial for tht-
.releasf of airborne radicactivity through coristruction openings in the.. roo '
Some potential fer damage to the CCW surge tar1k *and other components in this area exists while the de-tensionin~ process is in progress~.
Th~ htat load en the CCW system during this:period was not addressed in the S The SE riotEG that the surge tank was re:quired only for
"long ~erm" CCW operatio The duration of "lo~g term" or a
. destription of hEat loading during that period were not addresse Further, no contirigency action were identifit-rl if da11:age to the CCW system should occur.*
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. The.licensee addressed the abcve noted iten1s in a later revision to th~ S The sc:op~ of the SE was broadened to include a small hole in the roof of the fuel pool building through wh~ch cables would pass to facilitate ~ork in the CCW surge tank roo Proper precautions were tak~n in the SE to mi~imize new air leakage paths. These.precautior1s, coupled with the negat:ive pre:ssu.re in
.- tli"e-fuel pqor-area, will assure-no air out-leakage from the roo The SE was also expanded to incorporate further ~rotective measures to prevent damage to the CCW surge tank *. The staff reviewed the updated facility change package aPd inspected the CCW surge tank room during the modification proces The latest revision to the SE adequately addresses the staff's *concerns. Thi item is co~sider~d close l I PDR ADOCK 05000255) l Q.
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pp~~~l!~~-90017-03, 04 The SE for the Auxiliary Building Modificatior1 for contair1mHt personnel access alsc. hiled tc address the potential release of airborne radioactivity via the acct:.ss openin This SE was revised by expanding the sectior1 detailir1£ ver1tilation flow -paths and potu1tial airborne radioactivity release. The staff
'reviewed the* updated faci 1 it.}L change package and inspected the containment access buildin Precautions taken to ensure that the fuel building negative pressure is mair1tained are adequate. It was verified that the auxiliary building entry doors were guarded by s.ecurity personnel when left open for personnel acces Item 90017-03 is considered close REquired Technical Specification changes have been submitted by the lfrensee~
The facility change package revision which r:eflected the licerisee's commitments
- to submit the changes ~as rtv5f~ed and found acceptabl Item 90017-04 is cot1sicit:-r-ed close f'P~!*. l!~~-~QOl 7-02-DfSCRI PTl{Jti *OF-*lHE -cONTAI N~IENT -AND-'- THE- "TEtiiPORARY ACCEss** OPENING>
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The Pc:lisacies coritairin:et:t is a prestressed concrete six-buttress' structure with, a circt1lar* flat base.slabt a 1.6.0 foot high vertical c.:ylinder and a shallow dorr~ The ir1sicE diameter of the co.ritaitin:eflt is 116 feet. * The fnside face of the containn1er1t is. lirit:d with a 1/4 iric.:h steel plat The dorr:e is 3* feet thi_d and
"is pfrstressed with 165 teridons grcupt-d in three sets. The cyllnder is_ 3 feet
- 6 foct1es thick ar:d is pr*estressed With 522 hoop tenclor1S arid 180 axial ter1~on Each tendon is made cf riinety (9C)-l/4 iric~ c'iameter high strengU wires.*
Iriitio11y the opening cut wi11 bE about 29 feet high arid 26 feet wide and is to be enlarged tc 32 ft:-t>t high arid* 30 feet wide to meet the restoratior1 coristructiori
- reqlliremt:*nt.. The analysis is b'ased on the larger opening. *The lower edge of t:he w:eriirig is about 60 feet above the top of the base slab*.. Seve11ty-b10 of the.
vertical tendons and sixty cf the hoop.tendons will bt ee-tensionec Fifteen cf tht.c!e-ter1sioned vtrtical tel.dons attcl thirty-sE*ven of th~ dt:-ter1_si0ned hoop teridor.s which*pass tht'.ough the oper1H1g will be removed and reused. *The openirig
\\'li11 be rr,ade by a wire cuttirig nietho Except for two small concrete sections
,removed to facilitate coristructfor1 of the trar1sfer *rail systern. the cut-out bled: will be removed in one piec After the coniplttiori of the transfer of the SGs the opening will be closed and the.contair1mer.t will be restored to its
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-~riginal configuratio REGULJ1.TORY-CONCERNS - -
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-~ The-c-ompone-nts -~1hich-will be cut and replaced includ; concrete~ reir:forcing bar tet1dori sheathing and stetl lir.e The tendons arid grease will be removed before c:uttin The tendor1s \\'lill b~ reused in the restoration. The concerns in such an operation, which werf highlighted as open item 90017-02 in the staff's*
.insptctfor, of the related facility c.hange packagl's. are as follo\\\\'S: The behavior of the cor1tairin1u1t structur*e at the timt-when the operiing is cut (with the ver*t iteil or,d hoop tendo.ns arour1d tht: opening bt:ir:g dl:-tH1sioried) resultirig in a contairiment uns_ymmetrically prcstresse :
The creep and shrinkage of the concrete used in closing t~e opening, which are expected to bt larger then the surrounding concr~t~. resulting in higher compression in adj~c~nt concrete and in mer~ lo~s of prestres.
, The creep and relaxaticn of the reused tendons potentially resulting.in
_larger prestress loss~ The locatior1 of.cadweld splices for*rei.nfo.rcin~rbars*:-;at one sectior1 withou staggeririg anc;I *the use-of s i stH sp 1 ices fo_r qua 1 ity ~contra l. both ~f which may result i~: reduction of the ~trength of.-the reip~orcing_ bar.
Tht lto.ktightne~s of the ~onnection of ~ew tendon sheathing with the existir1g_ shE:athing 1.(*.PH:vent grtase leakage into* the concrete,.
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The effect of withdrawing and rE-iriserting the tendons may**wear 'the co.r_ruga~ecl sheathirig**'o.nci possib*ly ca*use*-1eakage 'of grease;*.
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lJ1t effec*t of a* structural* ir1tegrity ~te~t at 115% de:sigr: pt'~ssure:*on the contafr1mt:r.t (due to.loss of.. prestress ;,, tendo~1~). *
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The above ccr.cerns were conveyed _to ttie.licensee arid its.ArchitectiEngine~'r--**
(A/E) duri.ng ir1spectior1s ct tht! Palisades site and the A/E's offic.. * *
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. RESOLUTIN~ OF STAFF 1 S CONCERNS*:.:
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, In order to rt!spon~ to c_o.r!_terns.ilrisir:g fre;n; *cuttir1g ar;-.cp_enihg ir1 the*;
- *-co:ntairiment. Ut:_n.censee *had*-;ts A/E., *sechtel*Po~a~r Corporation, perform a:
deta i lu~ finite e-1emer.t.. ana*1ysi s for the whei le co.nta ir!mer1 The fc l lowing
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sur.;n;arizes tht-fiiiitt t:lemel1( analys_i~ as performti_d by -~h~ liceri,see:
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The* contafoniuit cy1indH togtthE-*r with the buttresses ar.d the ring gir'_de and the dome a.re idt,alized into 1400 e*lernent The coritairin;tmt is assumed t.o bf fiXEd.at tht foundatior1 leVEl *. The loads torisidered a're dea *
prl'stress (wtiith rarrgE:s from fun. maximum dettnsion arid minimum detension).
sEismic. wind-~ and therma Eight basic load tombinatiorrs*are cor;isidtrec!***_
for* Hie ccritoinrr:ent sht:l l structure eve 1uation duririg tht*. E:xistence. of the
- trar:sfer cipuiirr Eleven basic load combiriaticiris au; used to st.Udy the co~tain~ent sh~ll stru~t~re behavior after th~*c1ose-up of the transfer.
o_pe_n~_ng ~it~ __ tWQ differer'1t mc_d_uli oJ_ el!lS.t.ici.ty.fer concret.... --* :
- The finite-E:fements are mostly' rectangula' Th' elerr*ents are co.nsidered uriiform thin plates with the four* corners of each e1e.n1ent as, nodaJ poi~ts for* iratercCir1r1ecticn between elern£ont The. plate element as idE-alized may be sairl to have five dtgrees of freE-dor Be:sica11y the approach used is r:early the san'~.- as that used by ethers p~rformi11g firiitt t-len:ent computer analysis for such a structure. The r~sults of tht finite element ar.alyses art in terms of stresses at the center of the ElemEnt which are compared with tht allowable values as sptcifi~d in the FSA The ratio between the str~ss obtained and the
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,e-4-allowablt is defined as *tht: utilization factor (UF) which serves as critt>rion of acceptanc To be acceptable the UF should be *equal to or lt.*ss than one.** For any UF grea!er than one in any element, a process o evf:ragi11g tht: stress£*s amor1g the adjacent elements is ptrfcrrr;ed. Such a s ituat ior1 ~x its at _"points of d_i sccrnt inuity or concentrated loads. *.
The use of averagirig tht: stresses of neighboririg elements is justified by tht:* licensee on tht: basis of the actual bt:havior of concrete structural* **
ele~ents~ Actually it should be noted that the stress distontinuities between elem~nts art *.*a direct result of t_he :strt:*ss patter_ns assumed in the e1ernu:t Each' element is stressed independently of its 11eighbors, which.**.
- actually is riot*: the case. Therefore, avE::rOgir;g the stresses of 11eigt1b.orir1 elements should give. a very reaso11able approximatior1 of stresses iri the
~lereents of the region.~
Th, results of the ffoitt: element ana'lyses were corr:parE:-d_'to ttiost' of the origir.al FSAR a.r.a1ys_es for the same C(Jllditio Th resL1lts ger.ero..lly are withi11 reC1sonable agreer.*eri At one lOcatilJn~ the junctior1.of the cylinder with the four1clation rr:a*t where :the present ar.a.lys'es _give n1uch higher bending
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va1uf:~ as explained by the litH:sH h ttiat the pr:t!sH!t *ana1yses consi.dtr
- thf cy1ir:dt:r as -fixed at the jur:ctiori while the origirial analyses take( the ba s~niat flexjb i 1 i ty il)tO.consideration.~. Tht licensee us~d 'the 'higher'_;; '
ber1dinu'.n:un.erits arid shE:'ar.s.to cht:d the.desior1 of the coritairin1er1t at th _
lc;c.atio'n -and four:ci it,_to* be ader;i1at ThE a~c:lysts *do *not fodicate a eibr;ormality irf f~e overa*11-behavior 'of the C()fltairimHif" for all the
-. t_crndUior:S' specifi,e ~,, a prestresstcr concr,ete structure, creep and 'shri':r;kagt cf concrete an: causes. -
. of pn:strHs. 1 oss.. Shr tn*ka9E.. eri _ses ir. r.H1 ly p 1 ~ced coricret~ as a r~ 5.u lt_ 9f.:.. --.-*.
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(or"\\Ct~ete dryhg. *Creep 1s lciac!* related~ that "iS, when concrete.. *-is uider
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- *.. _.,_ sustained 16ad,. then is plastic-deforriiatiori ir1 acidit ion to-thE-t:1astic: stroin;, -.
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- If th* Jood* is r*el~asec!, Jhe**elastic strairi. i-s fully n*covered but* creep is (Jt,ly partis.lly recove*rE!d *.. In.a n£w.ly cast *concrefr ml'mbtr the* surface :i_oncret~ - * **
ur1der96£*s shrinhgt:.* due to drying but is rtstrafr1t::d from doirig sc :by tht fottt*ior rnncn*te and the reir1forcirig bars or both. It is thus subjHted to tensile* * * _ -
stre~s uitil the -occutrence cf surface CQ~crete crac~s which.relievE the 'tensi&n *
. *crtep ar:o shrin~age* an ot irideptrident phenomeria 'to. which th~ pririciple.of. -
suprrp.os_itfor1 can be applied *. However, for sinipl.ic.i.ty the common practiet:~ is to_
cc~sider the two phenomt>n~ to b~ additive.: Fer tht: Pilisades concrete. in the transfer opening, Bechtel co~1si.ders the effect. of.shrinkage on concrete,
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reirifortir:g steel and tt:.e lin"er arid. firids it. to be negligibl For creep, th£:
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__.. e_f f e('._t i ~ __ s 1.1)~ i ed i_n _the_ a~!a ly s_i s by _ucs i r:i9 a J_o_w~r IT*Odl! 1 vs. cf eJ p_s.t i c_i ty _ f Qr
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cQn*crett:* ~t:i:ch *is judged to be acceptable *. The* re*sult of such ar.* ar;alysi*s does,:
- not i.r1dicate any adver_se effect. It is assured by the 1icer:see that the -
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-'rr:aterials Sl":'lec:tt'd for-the concrete tr:i>e will be such ttlot it has high compressive strength*with low creep and shrinkage so that the values u~ed in the analyses*
are conservativ The stn*l li11H_ is not iricluded in the firii.tt eh..n_1ent analysjs n:ode Bechtel hi!s perfom1ed an ar;alysis of the lintr ~*late through tht' c~.s1.1n1ptior1 of st,rair1-ccnpatibi1ity betwt>err the lfoH plate and concrete shtll arcund tht> opH1in The information on ccr:cretE:: stress arid str-cii11 is fron: the finite eltment or1alysi On the basis uf this or,alysis, the licerisee concluded that tht: 1fot:r
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-5-platt:' iri tht' transfer opHirig is structurally adequat Tht: *f"iriite e.len:ent anal.,Yst:s ahc take into c:onsider*atior1 tht: load conditior1
- which* occur durir1g o structurei 1 inttgrity test (SIT) ~ii th reduced prestressir19 tendon forct*.
The results wncluded that tht contairimtnt car1 withstar1d preisures up to ~nd above 11t% of the dtsign pressur *
Jn order.to check this to be truly the case, structural displacement det'Hn-.inaticn and concrete cr:ackir:g size rr:easuremer1t duririg pressut'ization and depressurizotior; of the coritairiment will bE performe9 espHially i.n the area affec:terl b~. the transfer openin Transducers a~d invar wires to measure ciisplac:t:n:ents of tht conta.irimer1t c;yliric!H wall will be-installE.-C at the transfer cpnii1g area and other' locations thrcughout the. containment cylinder wal Concrete.cracks will bE rr:apped at t.hl'.fralisfer opening area as.well as ether cor.:paratle ares has been ct:n:(J11strated by these samt= pr*ac:tices carried out in the clcsirig of the original c9n_sfructil:r;openfog.*" *
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Sheathirig Joint-: A one feet coupling ~.'ill bE insta1lec~ i.dth.six irict1 cvt:r1,ap ch each side ~f the juint an¢ will be:~ealed with ~~oxy tir caulk arid taped to provide a lt:ak tight se<il. *
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Sheath~~g - The withdrawing and re-i~serting of the tendons removed from the e:pening area* wi1l not rHult in any danioge t.c*the st1f:othir:g greeter than tha of_the original iristal1atior1 in view of the fact ttiat the st1eathir19 has been previously filled with grease resulting in less friction~l force ~uring tendo n~vemen *
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. ~oricr_~tir!g* - _In closing_ the transfe.r c;_periing.wi_th r.ievc ~oncr_ete,_ a* cc.r.crete mi~--,
1hat is clesignt:>d to devt:>1cp a high ec.r-1)* strer1'gth alor1g with Hhibiti acceptable creep a_nd shririkagt: characteristics will bE use The c:cncrete ~1i1l
'be plated in the forms in ~4-inth layers at the rate of 4 feet per hour utilizing tremfo~. ere eh:phant trur1k Plo.cEment of the cor*crete \\'lill ccntinue until it is* appr*oximately six inches from the top at the inside face of the wall. The*
tl*p-of the oper.1irig is sloped so thcst tf1t thickness of the concrete lciyu varies fr-en: 6 focf1ts at inside face to 14 ir;th~s ot the C:litside fac "Master-Patch 20" will t~ used for this top layer. It has the characteri~tics of.high eorly strtngth with low shrirkage~
-6-The replacement concrete will be essentially stress free prior to.. tendon retensfor:irrg. arrd therefore there will be sorre dlfference ir1 ttie state cf stress*
bttween the new and adjacent Histing concret Thf! effect of this* differer:ct is evaluated* in the finite element analysi~ and found to be of littl~
s igriifi ca nee~
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Creep and Relaxation cf ReuseCf Tendon - In order to study creep and rela~atior;.. *,.:
of the-re-used tt11dons three wires wi 11 be pul1t:-d from the removed tendon,Samples of the wires \\<.'ill be tested* to. support the er1gir1eeri'rrg ar1a.lysis. *
E~f\\bY~Iill_ 9f.- b!f~g:E ! S * RESPONSES
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The staff. has rtvie~JE'C! the liCt>J;See's responses to. the ~hove concerns, es pee i e< 1 ly ttiose arr.er."b le through the fin.He e leme*nt ar.a 1yses and found th~t:.
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(1) The analyses are detailec!*and comprehens,iH.-
They iricludtd 'the whole ccntainrn~nt shell and considered all a~plita61~ loads* and load con1biriatio11 The-results of the analyses dc*not'iridicate arry abncrmal b~havj_or of_ t_he cor1tairrn.er1t either lc*ca.lly or gl9bal1.
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(2) Jhe technique of repla~fig the concrete i~ t~~ -0pening*and the.~roce~ure*
. cf evc. luatirig* stirinkogt and th_e use** of lo~;er concrete.modulus of elasticity: *
to con~icitr th.e. effect of creep and shrfokagt: or:i contairirr1er1t: appear to be- *
re-asonabl.E: ar;c1.,1re ac_c~ptabl *
- (3) The procedure: cf analyzirig the stetl *1;r;er ir1: *the *oper:irrg arf:a is acceptablt and th~ rt~ults appear to.be reasc~a~lE. - *
The staff.'s rerr,ainirig_.concerns are *related pr:in1arily tc quali.ty assura.r~ce a~d.
qi.:e:lity cor~trol. Tht:.staff bas four1d*ttie licensee's.respcrises to these concerns tc be: acceptabl \\..'-)th regard 'to t~e n-1a*r1r;er 'i11 ~1hich cadweld* s.plice~* wil.1 bt:.
usec t.t:E: 1ic.er;see respor*ded-thc.t the te.ndoris are the prir1c.ipol strength H*sisting*
.. e1emerts (Urt n:foforcitrg bars are provided *tc c:oritrol coricrete cracking due to therm~1 *1c;ads am! other forces :arisirig from structura*1 disco11tir1uity). * *.
- Furtht:rrr:on*: such. cadweld.splices. were used iri the c.losing of* the origirla*1:..
io~struction opening. *Therefore the ~adweld s~1ices ~s*used.will not je6pardize
.the structural irrtegr.ity of the corita-irrmer; **The~reascning,is convincing and..
the. concern~ with respect to the cadweld *splices are ~~tisfactcri1y resolve *
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COt~CLUSION
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On the basis of staff's review~and-site if1spectior1 of the fir;i.te elernent.. analyse~.s
- perforrrE-cl.. and -of the mE=asures.to be taken ir, qlio Jity assurance by the licensee, the staff concludes. that the cutting and closing cf the transfer opening i~..
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support of the stE;arn gerierator replacem~nt shcul~ not jeopatdize the structural integrity of the contairrmen As su,ch, inspect ion report operr :f ten1 90017-02 is ccrrsidered clOse Hcwever, fintil acceptability cf He* Pc.1isaciH containment is subject to th~ staff _review and.acceptarrce of the structural_.Hitt:gr*ity test rtpor Principal Co~tributors: C. P. Tan B'. E. Holian Date:
November 29; 1990
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~EFERENCES The-evaluatior1 and conclusion cf thi~ rtpcrt is based on staff's discussior1 with the licensee and on insp~ction of docun~nts at Palisades Plar1t Site and at licensee's A/E office. The documents inspected*are:,..
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Occ.un1er1tation or: finitE-element ar.alyses, Report_Nos. C-025 to C-31 inclusive, C-035, C-036, C-038 to C-4 Task plan summa:ries, Revision 0, May 15, 1990 *.
T~e adequacy of steel lhH plate in the contair1nitnt opening afte*r t restoration, calculation No. C-06 Effect of n~w concret~ shrinkagE on the contai~ment. shell, calculation*
No. C-032..
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Prim_ary.reactor* contair1ml'fr1t, stn1c:tural integrity test procedur*e, P~li~ades Plart, CPC, Bechtel job no. 2055.
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letter to NRC from *David* Hoffnl~ of consumers Power. C.ompany date~:
- September 20, 1990*.
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- . t f-., fcxed sheet fron*1:Consurr:ers Po~*Er orr' c*ont~irin-1trit ConstructilJfi' opening conc:at plac:t>n:erit dated October. 29,_ 199,\\'
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