ML18018B416

Forwards Nonproprietary & Proprietary Responses to Request for Addl Info Re Criticality Analyses for Spent Fuel Racks. Draft SER Open Item 360 Completed.Proprietary Response Withheld (Ref 10CFR2.790)

ML18018B416
Person / Time
Site:	Harris
Issue date:	10/21/1983
From:	Mcduffie M CAROLINA POWER & LIGHT CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML18018B417	List: ML18018B416 ML18018B418
References
LAP-83-483, NUDOCS 8310280014
Download: ML18018B416 (39)

Text

REGULATORY Ig/FRMATION DISTRIBUTION SYST (BIDS)

ArDOEEPTDN NERL8810280010 Doc ~ DATE1 88/10/21 NDTAR11201 No DocKET FACIL!50 i'F00 'Shear on Har ris,Nuclear Power Pl ante Uni.t ir Caroline 05000400 50440j, 4hearon Her ris Nuclear Power Plenty Uni,t 2r Caroline 05000401 AUTH~ NAME, AUTHOR AFFILIATION MCDUFFIEr M ~ A, Cer ol ina Power 8 Light Co.

RECIP'NNAME'ECIPIENT AFFIlIATION DENTON<H ~ Ri Office of Nuclear Reactor Regul=ationi Director.

SUBJECT!

Forwards nonproprietary 8 proprietary responses to request for addi info re, cr'i,ticelity analyses for spent fuel racks>

Draft SER Open Item" 360 completed,Propr ietaI y respond.

withhe,ld (ref it)CF'Rd ~ 790) ~

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OCT 811983 SERIAL:

LAP-83-483 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT NOS.

1 AND 2 DOCKET NOS.

50-400 AND 50-401 DRAFT SAFETY EVALUATION REPORT OPEN ITEMS AUXILIARYSYSTEMS BRANCH

Dear Mr. Denton:

This submittal ih in response to an NRC reviewer's request for additional information addressing the criticality analyses for the spent fuel racks referred to in CP&L's letter dated October ll, 1983, Serial No. LAP-83-472 and completes ail requested information for draft SER Open Item 360.

Enclosed are:

l.

One (1) copy of Westinghouse "Shearon Harris Spent Fuel Rack Criticality Analysis" (Proprietary).

2.

Forty (40) copies of Westinghouse "Shearon Harris Spent Fuel Rack Criticality Analysis" (Non-Proprietary).

3.

One (1) copy of Application for Withholding (CAW-83-86) (Non-Proprietary).

4.

One (1) copy of Affidavit (CAW-83-16) (Non-Proprietary).

This submittal contains proprietary information of Westinghouse Electric Corporation.

In conformance with the requirements of 10CFR Section 2.790, as

amended, of the Commission's regulations, we are enclosing with-this submittal an application for withholding from public disclosure and an affidavit.

The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission.

Harold R. Denton Correspondence with respect to the affidavit or application for withholding should reference CAW-83-86 and should be addressed to R. A.

Wiesemann,

Manager, Regulatory

& Legislative Affairs, Westinghouse Electric Corporation, P. 0.

Box 355, Pittsburgh, Pennsylvania 15230.

Yours very truly, MAM/pgp (8205NLU)

Enclosures M. A. McDuffie Senior Vice President Nuclear Generation CC:

Mr. B.

C. Buckley (NRC)"

Mr. G. F. Maxwell (NRC-SHNPP)

Mr. J.

P. O'Reilly (NRC-RII)

Mr. Travis Payne (KUDZU)

Mr. Daniel F.

Read (CHANGE/ELP)

Mr. R.

P.

Gruber (NCUC)

Chapel Hill Public Library Wake County Public Library Mr. Wells Eddleman Dr. Phyllis Lotchin Mr. Ahn D. Runkle Dr. Richard D. Wilson Mr. G. 0. Bright (ASLB)

Dr. J.

H. Carpenter (ASLB)

Mr. J.

L. Kelley (ASLB)

+ Denotes parties which have received the proprietary information.

Shearon Harris Nuclear Power Plant Draft SER Open Item 360 ASB Question 9.1.2 In order to permit us to evaluate K ff for spent fuel pools, provide fuxther information regarding all fuel to be stored, fuel distribution within the pool(s),

a detailed description of the storage

racks, a description of the calculational methods used in the determination of K f< by CPSL toegther with a discussion of the calculation and mechanical uncertainties considered in the calculation.

Describe how control will be maintained over the location of the fuel in the spent fuel pools.

Response

The maximum U-235 enrichment is 3.9 fox the Westinghouse 17xl7 fuel.

The rack parameters are shown in Table 1.

This table will be included in FSAR Section 9.1.2 in a future amendment.

The previously mentioned proprietary submittal addxessing criticality analyses for the Shearon Harris spent fuel racks is attached.

(8153SAL)

TABLE 1

SHEARON HARRIS SPENT FUEL RACK DIMENSIONS Fuel Type:

W 17xl7 and GE 8x8 RACK TYPE C-C SPACING CELL I.D.

POISON CAVITY POISON WIDTH CELL GAP (NOMINAL)

POISON THICKNESS WALL THICKNESS WRAPPER THICKNESS POISON (GM-B10/SQ.CM)

POISON

10. 500

8. 750

0. 090

7. 500

1. 330

0. 075

0. 075

0. 035

0. 020 BWR

6. 250

6. 050

0. 060

5. 100.

0. 045

0. 075

0. 035 0.0103 All Dimensions in Inches (8153SAL)

3 4

~Tl~r Z~<

A VZYSZS 3.4.1 ~~H WTTZP~<CKT CH rACZOR Critical' of fuel asse. alies

~we ~t fuel storage rack 's prevent& by

~M design o2 '<<'.e racks wn'h limits uel assmhly

'interaction.

This is done by fix~ tne mimmn separation

'wtwe asse.-.al'es ~ i"we~'~ neut~ poi~ between asse..alies.

The design basis for preventing criticality ot'tside the reactor is

that, including uncertainties, there is a 95 percent probability at a

95 percent confidence level Cat

• the e" ective multiplication factor (K ~f) of "the ue~: assanoly ar-ay w'~1 be less ban 0.95 as recannended

'a MTSi'%210-1976 and in "~~ position or Review and Acceptance of Spent >>uel Storage ard F~lirg Applications".

allow'-.g are the ~Mitt<~ that are asswiM in i~ ting t'ms desi~ ~sm for ~ Shearcn F~~m spent f el storage racxs.

3.4

~ 2 MORAL STORAGE 3

~ 4 ~ 2 el PWR c~

a.

The fuel assembly contains "Ne hignes" e "icimo~t authorized wi"Mut a~ contml rcds or any nonconmi~ed bur;.able poi~ aM is at its rest react've point in life. The

~

ic'.zeat of >4e 17 x 17 Westinghouse optimized fuel assay is 3.9 w/o U-235 wi 4 no depletion or fission produc" buildup.

The mllcwi~ assarhly pa~et rs we e rredeled:

h~~-:OUSE PJZL ASS~cd (17 X 17 OFA)

'I~~~ of.=uel Beds pe

assy, Z'"c-4 ~ Clad O.D.

Clad Thickness Mc'el Pellet 0:D.

0 ~

36"'.0225" 0.3088"

-uel Pellet Densi"y

'el Pellet Dis~g Bcd Pitch 2 mber Zi c-4 Cue T&~s Cuide T~ O.D.

C~>'de i~ sickness 95% Theoretical 1.20%

0.4c6" Scuare 25 0.474" 0.016" T?m assavhly is conservatively ~cled wi"4 waie" replac~~

the assembly grid mime and no U-234 or U-236 in the

= el relict.

I U-235 burn~ is assumed.

b.

The storage c ll remi~ geanet~ is shcwn cn Figure 3.4-1.

C ~

The moderator is pea water at wa temperature witM "".e design 1imits of tNe cool Wch yields the largest reacty.

A conservative value of 1.0 ga/cm is useD for ~e density of 3

wate

. Ho dissolveD boron is includeD in De water.

d.

T?e array is either infinite in lateral extent or is sumunded bv a consecutively c"..csen reflector, whichever s appropriat or tM analytical nadel.

T."e vaginal case calcula" 'on is infinite in lateral and axial ev~t.

Poison plates are mt necessary cn the per'he~

of ~e rack rvcdule excect

'or the sides of the module ad jacent to another rack necule (eithe>>

a PNR rack or a

aMR rack)

~ riever for the.

Shearon Harris FHR racks, bison plates are used cn all mcdule peripneries except fcr om Mule in ea& pool.

Poiscn plates a e cmitteD w~cm one side of the module (6 cells) for cai~~ili"y witn "Ne su~eil-lane inspect'n program.

Calculations or ~use racks with "Ne poison r~ved i.Zicate a.

rack. Therefore,

~he rxm~M case of an i"+i~~te ar ay of bison cel's is a conservative assumption.

e.

Rc".~cal unce~~cties a~xi biases due to me"~cal tolerances du '

cons~~wc"'cn are treat+

by e'~Mt us~

"worst case" m:diticns or by ~fora'~ ~~itivity s udies to cot '~ the appropr'at values.

-z.e i ~ include

~a ""a a"wlysis are:

poison pocket Mc~ss sexless steA thickness

~ 23 center-to-cute spacing can bowLzxf The calculation rrethcd uncertainty and bias is discuss'ec"icn 3.4A.

f.

C"e~t is

~~en for "Ne neutron abso~~icn in full le~%

structural materials and in sol&~

r materials added specifically for rwumon absorption.

The mi~mun poison loadi~

(0. 02 aa 310/an

) is asnzneci in the coiscn plates aM B4C particle sel" shielding is inct,uded as a bias in the reac"ivity calcula~mon.

3.4.2.2 BNR rULL a.

The fuel assembly con aim

"'ce highest e~ iciz ".t authori ed without any bur.-ale poiscn arri is at iw most reac ive point in 1'.

The ~mic.unmt of the uel assarhly. is 3.20 w/o U-235 with ru depleticn or fissicn product buildup.

nxdeled using the

%13.'cw'ng paramet rs:

The fuel asse..hl.y

~ s

'GMcPAL 2.ZCLKC HJEE AS~rLY (Bv'R 8 x SR)

Lattice Pi ch 0.640" scpa e

. =-uel Rods/~sanbly 62 Ha. Wate>> Rods/Asse-.hly - 2 Lacaticn of Yiater Res - Positions;.29

-.'36

%el Bod.Pellet O.D- 0.410"

=uel Bcd Pellet Lmiersicn.Densi z,954 Theore+'M>>-

Active Fuel ~ngth-6" ~tu a UO, 138" ~c~e (3 ~ 2 w/o U-235) i 6" i%a ura UO "uel ~ C'ad O.D. - 0.483" Fuel, Pac Clad Thickness 0.032" Fuel Bcd Clad Mate 'al Zirc 'cy - 2 Na"~m ~ O.D. - 0.591

~@ter PaQ LhicWess - 0.030" Mater Bra Material - Zircalov 2 Material - Zircaloy - 2 Thickness -"C'080" Inside Scuare Dim. 5.268" (min.)

Outside Scr'are Dim. 5.454" (radix.)

Inside Sauare Dim. 5.281" (avg.)

Curbside Sauare Dim. 5.441" (avg.)

Th assarhly is conservatively reeled wi"4 wat ~ replacing the asseably arid ml~ and no U-234 or U-236 in the

~ el pellet.

No'U-235 buxom is asmmed, nor is any credit tom for cado1.in-ium urna'ale poison.

F'gure 3.4-2 shows a schwa~.tic of the mt fuel storage racy illustrating the checkerboard arrangement of cell modules.

Ficure

3. 4-3

'shows

&e rxrn'~l ~~,. ~icns of ~~vidual I

mcdul es and indicates he unit ce 11 rmde led in the ~O analyst.s e

c.

The Liberator is pure water at De t~rature wi""Ln the desicn limits of tho cool whi~ yields tM larcest reac 'i"y, c~ervative va'e of 1 0 aa/aa is used for

"~e cecity of water+

I

~

I

d.

he ar=ay is ei"Her 'w~mte in lateral ~v"~~t or is sue outed by a conse'm 'vely c'.-.os~ reflector,

~~i'c.".ever -m appropr'ate "or the analyt'cal ~el. De xmirM c se ~~lyrical revel is inf ate in lateral extent.

Oe follow v diensions were cled in the axial cirec ion:

Fcd Clad

=

159.5" 6" ra,~al UO (top)

>38" enriche5 (3.2 w/o U-235) 6" natural UO (bottan)

Cmrnels

=

164" Bora lex 151" r

Storage Cell Can 164" Poison plates are not necessary cn

~he pe 'phery of

~~e ~ck nodules sine adjace~

SWR racks are locat&

~

enough apar to preclude an increase in reactivity relative to

~he iaaf'ate ar ay mdel of poiscn cells.

Fur"he~re,

"'"a WR rack rxaules with rn poison cn the periphery are also located fa" enough

~cm the PWR mxiules to preclude an increase in reactivity relat've to the infinite array myel of ~ or WR bison cells.

e.

Mechanical uncertainties ~ biases du to r."ec tamcal tolerances during construction are

""eated by e'e using "wors case" cordi"ions or by per foui'ensitivity studies to cb"~i~ "he appropriate values.

'Khe itaas inclucied in the analysis are:

- rack assanoly "ole ances

- material thickness tolerances

- center-to-center spac~e uel chanel effects poiscn loading The calculational rethcd mcer~sty ard. bias is' "scussed Sec" ion 3.4.4.

L'"edit is

"~Men for

~~e

."~u-n absorb 'n in ='

leng ~

smctural mate ials arri in sol'>

mat

'als added specifically for neu"~n absorption.

'The mim~~~'ison load~".a (0.0103 B /n

) is ass~-,ed w t.e poise plates ard BC ~icie sel 10 2.

4 shie3.di~ 's

'~c3.uded '~ a bias '". ".e reactivi"y c lculat~on.

3

~ 4. 3 POSiiJLATED AC"~M~

The'o1.lowing pcs ulated accident we"e analyzed:

a.

Drcp of fuel asserhly cn top of racks.

b.

Drop of fuel= assumably nex" to the maoisoned pe 'phery of the racks.

c.

Traive~ent loading of wrong ype of uel-into.a s crace cell.

d.

lass of coolie systans e.

Water inje tion into racks Men used for dry s orage.

EaW of these accidents are discussed in the sections which follcw.

3.4.3.1 Er or Fuel Asservhlv on oo of Racks Four possinle accident scenarios can 'ce yes ulated as ol'cws:

1) drcp of a FnE assembly cn eithe a

Pw'R or a WR rack,

and,

2) drop of a 2WR assavbly cn eithe a

PAR or a WR rack.

A uel assenbly d cpped cn top of the racks will be prevented by the

. rack s"wcture rcrn interac"'g with ".e ac"'ve fue s or+i in the rack. We top of the 'active f'el stored in the Bv'R racks 's a=prox-tely 13-. inches

~an. 6 tco.of.the,.rack'uture;

""a ~ of the ac" ive 'uel s ored in the FNR "acks is approximately 8,.5 'ches

=an

~

'l C ~

top of ~w rack s"-~c".

e. M~.e~re, c>>culations sm ">et a s-.gle m>lated PhZ asse..zlv in wa"o~ is more "zan a single isolat&

=-~E assa-eely in water

gently, "Ne worst case condition is

~we d"cp t 0 v~ a M racks react've (7 -- "-0.9)

(iC = 0.7).

Conse-of a ~ asse. Sly cn Calculations show "'sat even for an infini"e ar ay o" %Z asse..hlies separated Ran eau o"Ne by as little as 7 inches of wate will have a ~'Lnal 4 -f of less "~ 0.9 which cl~ly darans" a"es "'~t I

an assanhly 8.5 m~ches

~cm active uel is essentially isolatai.

3.4.3.2 Drop of Fuel Assevbl Next to "Ne Unaoisoned Pe Men of the-Sac&

The "erst case" corxiiticns for Ms ac iden" xxxlc be "Ne drop of a.

E% fuel'ssembly next to an uncoisonM pe i=heral storage cell of a PNR storage rack.

This situation could lead. m an increase

'~ iC--

far the array of stored'uel.

Therefore,

"'~ double c=nt'gency principle of ANS 816. 1-1975 is applied for tMs ac ident. ~'

principle states that it. is unnecessary to ass~~ ~ mlikely, independent, concurrent event.s to ensure protection agains" a

cri"icality accident.

Thus, for acc'dent conditicns, t?

presence of soluble boron

(-2000 agn) ia the storage pool water ass~~

as a realist'c initial c=nditicn since not ass ~ i"s presence ~d be a s~rxi unlikely event.

En ~

~~

of Nes~~house 17 x

17 OFA fuel, me presence of approxmtely 2000 pan boron in a+1 water will dec ease re-ctivi-y by mare than 3'iC.

Thus K --

< 0.95 can be easily met 'or "Ms ef pos ulated accident since any reactivity irwease auld be less tM

" e negative wor> of Qe dissolved boron.

(

f.

3.4.3.3 Lmdve~ent Evading oz the Nrcra Tvoe o" =uel Into a Storace Cell The design of

~>e s"arage racks is such t~at a.

PrrR fuel assembly (because of'its ohysical size) cmct be inacver ~atly loaded into a BNR starage c ll. Tf a ERR

. fue3:. assembly is i~ve~~ently 1caded into a PNR storage cell, Dm design basis K ~

is not exceed since the single Br~ fuel assembly is less react've "~ the, 'Piv'R assenbly.

3.4.3.4 Lass oz Coolish stags/Nate Lnjec"ion Law Ra.cQ

%hen Used for D Storace For &e loss oZ..~ling.accident the effect auld be a crease tea water nederatcr density.

This acc cent can be grou~ wide t"e accident in which the storage racks are used as a

new fuel dry storage facility ard water is introduced for Eire +'ch~ or ~

other abmrnal situation.

Scth ac=idents involve mnerator de.aities less than 1

gm/c=

aaD sugges"

" m optimum tide ation condi tiorl.

Hawever, the "optimun nederaticn" accident is rat a

prcb1.em poisoned fuel storage racks.

'the presence of ooiscn plates ranges the mnditicns necessary for "ootimt~ reiteration" so that ec<

continually decreases as rrrderator density decreases Eaza 1.0 cm/aa 3

to 0.0 gn/an in poison rack designs.

Figure 3.4-4 s~

&e be'navior oz K

as a

unc"icn of mderator ezf density for a EhR poisoned spent fuel rack ard Figure 3.4-5 shows a

similar behavior cr a PNR spe~ fuel rack.

3. 4. 4 CRITICALITYHVZYTZCPZ i4ZIHOD The design method which tsures

"~e c"iticality sa "ety of fuel assemblies in the FWR and P~E s~at fuel storage racks uses the ~PZX systan of codes 'r c"oss-se "'cn generation a.w ~~O ZV for (1,2)

(3) reactivity dete~saticn.

~

+

~

~

.he 218 energy cr~ c"oss-section M>>ra~

"Mt is the c=nmcn (1).

s ~~'

coiW for M~

cross-se mons

~M or "M storage rack ar~~yses was gene ated

~cin

~c. F/3-V1 dat.'he NZTAhT prcgr~ (2) acds ~

M~s library R sel f shie1 de resor~ce cross-'sec ions t lat are ~propriate for e ch par"icular gaz"e~~.

The Sorcneim Lethal Treat..ant is us% m the NTPRL prcgram.

r~e~~

ard soat'al we'ght-i~ of cross-sections is oerMrmed by the XSDRIP41 orcgram wn'ch (2) a cne iizensiorM S

transport theory code.

These mul"'~~~

c"oss-sec"'cn sets are then used as input u WO XV, Rich is a (3) tMee cirensional Hmte Carlo theory program designed for reac"ivity calculations.

The calculatiorr'+&cd 'nd cross-section va~ ues are verifiM by caapariscn with critical experiment data for assam'olies similar to those for ~ch the racM are designs.

P s

cenchmarking cata is sufficiently diverse to establish that the method bias aM c~~~ty will arply to rack conditions inich incude s~ng neu"mn absorbers, large water cars and'cw naderator der.si"'es.

A set of 27 critical experiments has

'ceen analyzed using -the ~e methcd to denonstrate its aoplicability to criticality analysis ard to es~lish the m6M bias and variabili"y. The expe"~its ~~e fran water moderated oxide fuel arrays seoara ted by var.'us materials (Boral, steel, water) that simulate L:K fuel shi"oi.-.g arsQ storace conditions, 'o

dry, narde" spec nzn uraniun metal (4,5) cyl~er arrays with various intersperse materials (Plexiglas, (6) sM and air) that derentwte

"".e w'de range of applicabili"v of "Ne methcd.

The results and st descriot've fac"s ~Mut each of the 27 bene'z-mark critical expen~ents are given in Table 3.4-1.

The ave ace K

of the hnchmarks is 0.9998 ~bien dmnstrates

"'wt there is no b'as assoc'tM wi"4 tM methM.

The soda& deviaticn of "Ne K

values is Q.C057 Q,K. The 95/95 one-sided

~ale anc~ ~'v'" ~ac"or for 27 values is 2.26., Tht's,

~Mere is a 95 percent.orc'cability wit's a

~

~

95 percent c=n=idence level "~et the uncertainty in reac"ivity, due to "~ meth',

is nc greate t'ien 0.013 5K.

These ze"~icds conform w'h H¹ N18. 2-1973; "Nuclear Suety C=iteria for the presign of Stat'n ~ Pressurized Water Re c"or Plants",

Sec" ion 5.7, Fuel F~lirg ~st~;- Mal N210-1976, Design Cbje ive or.L~R Spent Fuel Storage =acilities at Huclear Reer Stat'ons",,

Section 5.1.12; P2DZ H16.9-175, "Validation of Calculational He""res for Huclear Cmticali y Safety";

HFC Standard Review

Pgan, Section 9.1.2,,"Spent &el Storage";

aM the HRC Guidance, "~ Position or Revive ard Acceptance of Spe& "uel Storage aM Harali~ Arnlica-tions".

3. 4.S CBZTXCAZZTY PZQLYSIS This section presents the neutron mult'plica-ion factor K ff eff calculat& using'rm above meth'or the r.aninal designs of both the PWR ard. 6& racM.

Biases and uncertainties a"e developed for both rack tyoes arrl include consideraticn of t'. ~

ol'ow'g varia.

bles:

poison

loading, mison particle

size, rack construct'on tolerances, rack material sickness tolerances, water density aQ calculation mthcd mcer~inty.

This s~ion also cavbines 'Ne ncminal K

~ wi~A biases ani unce~~ties to develcp a final K e f e f for each tyce of storage rack (i.e.

WR or Pn1R) at a

95 pe cent probahili"y with a 95 percent confidenc level.

This se icn also presents

~he results of ser~itivity s-udies Rien

.s~ ~

"Ne'K f fcr eff center-to-c ster spacing, poiscn plates.: inally, a~y varies as a

~mcticn of cell, fuel ~midst, and poison load'm of &e sec"'cn discusses ~ ~LI&ticnof fuel racks loaded in De sere cool with PWR el racks and the gossibili"y of isterac"'cn between -"q M fuel "ypes.

I ~

I

3.4.5.1 PNR:-heel S

race Backs

a. Sinu~'O K feff Re K -~ for the ~i'~al design of De Rv'R

~ el storage racks was e

canpute9, by t'..e ~ ~e-m be 0.8968

+

.C050 (95/95).

h iCZha

@eccl ~ basM cn tNe man'~ di~~icns of the ~t cel3. shia cn 10 f'gure 3.4-1.

K'e~~~ua borcn load'~ o" 0 02 grams of B

pe k

sauare.

c ntimete was icnrporated in the riedel and "Ne water densi'y was 1 gram per cubic cenmeter.

he 5 el gzmetew.modeled for the remu~<1 ~O are given in sec"icn 3.4.2.1.

b.

Biases ard Uncer~t~es As discussed in.secticn 3.4.4 the ~O met'~ had a 0.0 bias with a 95/95 uncertainty of 0.013 Qk.

Calculations

'nave sham that Ken the boron in the poison plates is modeled as a hcnxqerazed mixture of elements, "Ne results a"e bias&

by a positive 0.0025 5k relative to excel.s Wch discretely define t'.",e B4C pa~mcles.

'Lhe rve"hanical tolerances of the

~3~ vidual storage cells and

">e construcacn tolerances of the PWR fuel storage rack will allow

~ a., b, c, 4 storage cells to be closer ~ether t~ the inches shcwn on figure 3.4-1.

For the Shearon Harris PHR racks

~>e wors" carhinaticn of mechanical m3.erances (i.e.,

she t metal th'caress, c 11 Z.D.

raax.'mum, rack grid

assanbly, ard cell bow~) will result in a,

cx,b,C, C.

roc"ion of Ae'wat~

gap Mtwe a adjac at c lls by

. ~mer-

aare, a

"GG-NCGO" gauge wi3 ~

be aap3.oyed'ur' cons~m~cticn to

a. b,C)c enure ~t the truu'ue1 gep or[

(eee Figure 3.4-1)

'te se u the a<,b,C,,<

wramer elates of adjacent. cells will not be less t>an J inches.

"-or a si~le ~ it is calculated ~t reac"ivity ccodes'ot increase significantly 'oecause Q.

increase in reac 'vity due to the wate cap reduc"'on cn. one st of.the c~n is o set

.by.~Me dec"ease in reac"ivity due to th ZncreasM wat gap cn "M opposi~'ide o

a.lysis, for "Ne ef=ec" of rec.anical tolerances,

~ever, assumes a wors" case of a rack ~posH o=

an ~y of grows of four cans where '~we wato~

gap betweoa

"~e four cans is 1 ~gbq g)C Mucm to Jincn.

~'reactivity incr~e of t~ c n 'gurat'on is

%w~d m'e 0.011 Qk and is

~.c3. <ed as a bias

" rm in calcu-la~~ ~

f'"M~

K f of tM rac!r-.

ef Scne mescal tolerances are not inc3.tded in t..e azMysis ~use worst case assumptions are used in tM ncminal case analysis.

An example of this is eccentric,assembly position..

Calculations were per formed wnich s~

that ~

cast reactive condition

s the assembly c ~tered in the can which is assumed in the rxxni~ case.

c.

Final K << for PWR Fue3. Storage Backs eff For normal oce"ation and using the method described in the above sections, tw.final K ff far tte rack is acta~ed in "'w fol exing manner:

ef rcmina1 4

met. vxi part

~ ~

ncmi 1~

2 1/2 where:

K

~ al =

ncaLnal case ~O K bias to account for the fact Mt ~"z~'cal tolerances can result in water caps betw~ oaiscn plates 1ess t an tXITQ lB1 e B

~thcd bias determined t an bene".m~k c=itical canoari-met.

sofls o

bias to account.for'ison par"'cle'elf-shielding.'

ks~~~ = 95/95 u;.c ~>>~ty in ~~ n~aal c se ~ K nczTU

'f=

95/95 ~~ce~~>>~ty in the ~mthcd bias.

Substituting calculat& values as developed in it~ a aM b, the result is:

K -~ = 0.8968

+ 0.011

+ 0.0 + O.CG25 + L(O.C050)

+ (0.013) j

= 0.9242.

Si.-ae K ff is less t~ 0. 95 includi~ mcerminties at a

95/95 probability/con"idenc

level, the acceptance criteria for cri~m-cality is rret.

d.

Sensitivity Studies for FeG Racks s~ the dependence of K f~ cn fuel are storage ceU. pa"ameters as ren~ested by "Ne hK, sensitivity studies w~e performed rela"ive ncm~~

lKxjel in

plates, the uel enrichment, and

'corm loadie of

~w pois-n the s-orage cell cen" er-tc-center spaci~

were vazie

. Figure 3.4-6 shows the results of W calcula-tions of the smitivity s d's

,storage racks.

for De Shearon 2~is RvR fuel lt 3.4.5.2 Bv'R Fuel Stora e Racks a.

Hcninal ~ K~~

The K -f for the naai.aJ.

design of the

~~R fuel storage racks was canputM by the ~ ~puter code to be 0.9274

+

.0033. (95/95).

he

~O myel was based cn the ren~a3.

dimensions of the unit c 11 sm n cn Figure 3.4-3. T¹ mL'n~~ borm load'~ of 0.0103 grars of per san -~we centimeter

.was i~corporated 'a

~he el and Ne water density was 1 gram px. cubic centzneter.

The "fuel ca ~~meters marveled for "Ne a+a~~.al ~O are. given 'a sec" ion 3.4.2.2'.',-

B'-ases a~ Uncez ~~es As discuss' a se ion 3

~ 4. 4-, the ~~0 me~.cc nad a 0; 0 bias w'4 a 95/95 unc r in y of

. 013 culations have shown "Mt when

~~e Mron in "~e poison plates is nxdelM as a haxqewzed mixture of elenents, t.e resul ts are biased by a icosi ave 0 ~ CC}6 <k rela,t'e to mdels wnicn d'c"etely define B4C ~. ticles.

The cons" uction'olerances for BnR racM allow for "Ne rxxni~

o.,C, (, a.

center.-ta-cent~"..saacinp

.. of storace cells of aches to be w, b,c,e.

~

randcmly reduced to i~ches for individual cells'.

Zt was calculated'Mt

~M inc ease in K ~ due to "M rardcm rMucwon in e2 cell conter-to-center auld be 'ess than 0.032 Q k wi& a (954 confidence/95%

probability) level.

Calculations for material thicknesses tolerances of the c ll Meet metal and the poison plates indicated that the increase in b,k auld be less t".an 0. 0079 with a (95'4 confidence/95% probability) level.

Xn additicn to tM uncer minty in th final K ~~ associate wi~N the ef various parameters discussed

above, there a "e other physical var 'bles that may affe K, Analysis s.~~ tMt the in' te poisoned array was narc react'e with uel c~~els included Can i" was without the cols.

Et was also deter~ed

"~mt the reac-tivity m higher, for the fuel (either c'~awe led or uchanne l.ed )

assemblies were lccatH exac" ~ y iz t.e center of the storacre c

M~

s.

The karaf 1ex poison is specified to con~a a

mim~ loading of.0103 ~vms of B per sn.are cen '~eter and t.at 10 value was nployed t'.mcghout the arz1ysi s for the sake o

conser-vatican.

The "natonal" case KZQ

( see item a) t'am

'nas already incoraorated

">z'ee "erst case" c"rditions

( ' e. dered fuel I, c~~els incll'dM, ard i~umun coiscn loaci~ )

~

c.

~".al K~--.=or ~'R =uel Storage Backs

.=or nonval oceraticn aM using "ze me~'~ cescri~

in t'..e a'cove sec"ions,

~Me i"M ( -- for the rack 's cetera'aeD in tNe follcvi~g iVBP>>1~~ ~

2 2

where:

= rxxn~aal case ~O K ~~

eff 3

= met~ bias determined

~crn benchmark c itical caapari-metL~

~ = bias to account for poison particle sel -shielding.

ks

.~ = 95/95 uncertainty in t'm rxzninal case ~ 6 f.

naninal eff'ech

= 95/95 uncertainty in

~he calculation of &e b'as a~w cons~can tolerances.

ks ~

= 95/95 uncer ainty ia the metM bias.

nethcd mat

= 95/95 unce~winty afsociat~

with material "sickness tolerances I

Substitu&m calculate values given ' itm a anci b

~a "Ne order list& above, "M result is:

K ~f = 0.9274

+ 0.0 + O.CG6 + L(.C031)

+ (.C032)

+ (.013) 2 2

2 eff

+ (.0079) 3.

='.9493

Since K - - is less

~ ran 0.95

~.cludi~ mcer~ties at a 95/95 prcbani3.i y/confidence

level,

~

ac e~~.co

. cri"eria for c=i"1-1 'y ~i'et ~

d.

Sensit'vity Studies for ~R ~cks sr'm de~adence of K ff cn fuel ~ storage ceM pararraters as recues ed

'roy "Ne HBC, sensitivity studies me aerfcr."ei relative to

~m nial, model in whiW <M 'co~ lca"'

of ~

poison

plates, tNe "uel ez'ichme..t, arZ the s"crage ceL~

coster-tc-center spac~

were varied.

Figures 3.~7 arri 3.4-8 shcw C~ results of the calculations of the sensitivity studies.

3.4.5.3

"-NR/BNR Racks in Same Poof.

In the S:earcn Ferris ~t fuel pools koth BvR arP WR eel storage racks may ce placed in tM same pool.

~m se mens 3.4.5. 1 arB 3.4.5.2 it was determined t>wt the aaximun mt~~n multiplicat'cn fac or, K,

for an infirm" array of stored

fuel, including eff'ncertainties was

0. 9242 for PWR fuel and 0.9493 or SK uel.

Calculations were per ormed whi~ s'~aZ t~wt, if the cell cen" er-line plane of the perip'ne al c U.s of a ERR rack were;,vista~.M at a dis~<

eaual to or greater than 9.0 inches

~an

~De cell centerline plane of the peripheral cells of a ~.ack, the result-or the ~ined configuraticn was less t".~ 0.94, Since eff the ~1 layouts irMcate ~t the 9 inch mi~mm is not violated,

~m accez~c cr'teria is rL~ fcr gaols contai~ hath BvR arri RvR storage racM 3.4. 6 AC~-~N< - CRITERLW:"OR MTZQ~rZTY The neutrcn multiplicaticn fac"or in "Ne s~at fuel cml shall a less t".ran or emm1 to 0.95, includ'~ all uncertainties, under all co%1 t'ns

~

Ge..emily,

<<Ne accep~~ce c=iter' or postulated acciden" c ndi-

"-'ons can be Ke==

0 98 because of -~ accuracy of ~ r'e.-'=~ used cowled wi 'a

~".e lcw ~c'oability of cc=mence.

=or

~ "am~.ce, PSSZ N210-1976

~w accepmce criteria for "'w "op"'-un mde aticn" c"ndition is K < 0.98.

Riever, for simplicity, the ac~~m~ce c iteria fcr all c'nditiora-willbe K f~

< 0.95 inc3.uciinp accidents.

l.

N.E. Ford ZZI, et el, "A 218-Group Neutron Cross-Sec ion Library in the

&Z( Master Znter~~ce Fomat.. for Criticality Safety Studies, '" ORL/CSD/

(July 1976)'.

2.

N.M. Greene, et al, "AHPX: A Nodular Code Sys an for Ge..crating Coupled i411tigro~

Neu"~-Garma Libraries fran HK)F/B, "

OAK,/'ZN-3706 (Lrrch

'976).

3.

L.M. Petrie ~

N.=.

Cross, "KE K ZV" -

An proved ante C~~lo Critical'y Prcgran,."

ORL-4938 (Novanber 1975).

4

~

S. R. Bie~i, et al, "Critical Separation Between Subcical Cluste s

of

2. 35 wt 8

U Enriched K)

Peas in Wate" wi"4 Fixed Neutron Poisons,"

Bat"~lie Pacific M~r&west Laboratories FNL-2438 (Oc"ober

'977)

~

5

~

S.R.

Bierman, et al, of 4.29 wt 0

"U Po~ sons g

Bat~~3.1e 1978)

~

"C"itical Separation Betwe a Sumac"itical Clusters cliched UO2 Rats

~ a Nate" with Fixed Neuron Pacific Nor&west oratories PL-2614

(~ch 6.

J.T. ~mrs, "Critical ~e D~~micna~

Ar ays of U (93.2) -

Net+3.

Cyl ".de s," Nuclear Scienc and ~ ne

~ ~,

Vol~~e 52, paces 350-359 (1973).

OEt<CIlt tARK CRIT ICAL EXPERIMENTS Enrichment 255 U02 rod la ttice

2. 35

4. 29 U ttetal cylinders 93.2 Re f1 ec tor water para ffin Sepa ra ting Material water s ta inless s teel bora 1

wa ter stainless steel bora1

air, air Characterizing Se clara t ion

~cm

11. 92

6. 39 4.46 lo.aa

11. 47

7. 76

7. 42

6. 34

9. 03

5. 05

10. 64

9. 76 0.08

6. 72

15. 43 23;04 eff l.ooa -'ooa O.993

+.oO4 l.oo5 +.ooa 0.994

+.004

~ l.oo5

+.ooa 0.992

~.004

o. 992

~

. ooa l.ooa

+.oo4 l.oo5

~.ooa 0;992

~

.Oo4 1.001

+.004 O.999

+

.OO5 0.999

~.005

0. 990

>.006 0.998

~.005 0.990

~.003 1.006

+

.005'are paraffin air air

19. 97

36. 47 1.005

~

1.001

+

.003

.004 bare para f fin bare para f fin bare para ffin bare alt air plex i ol ass plex ir~lass plex)g)ass plexiq)ass s teel

13. 7a 23.40 '.

15. 74

24. 43

21. 74

27. 94 14.74 l.oo5

+.oo3 1.005

+

l.olo

+

.004

.003 1.006 t.004 0.999

+.003 0.994

~

.005 l.ono ~.003

n

,J I

ts

~a~

I raaaaa

~SRSSRRS

~RRRRSSS

~

SSSSRRRS

~RSSSm RENRR

~RRRRSSS RRRRRRSS RSRSSRSS RRRRRRES

~SRSRSSI

~RSSSRSS

~SESSREE

~RRSSSSR

~RSSESSR

~RRRRRRS s

~

~

~

-UHIi CELL OF IttF IftI TE ARRAY

] SORAFLEX

~) b~)c) K

~,b,c, e PE TP f L II A II

] GAP

~,L,c,e j'iNNER CELL MALL a~ O)C,C I

SORAFLEX

~,4,cic MRAPPER PETA IL NP II F I~RE 3.4-3.

gpf fit(AL 0 fllEt(S fOttS FOR TYP fCAL SP Eg T FUEL STORAGE C ELL

~

~

~ g 4

~

I ~

I ~

~

~

~

I l

l o

~ i f

I I t

F IGURE 3. 4 5

K~~ - YS.

'QATAR i~OOERATOR GENS ITY FOR A TYPICAL "POISONED" PMR SPENT FUEL STORAGE RACK 1.0 TYPE Qf RA('K

'-C; [

j I'NCq PQ I SO<~

LOADI,",G, 0

Q2 gm <10/

2 FUEL, 3.5 l,"/0 M 17 g

17 0.5 Kelf 0.8 0.7 0.6 p

0.4 0.6 0.8 1.0 YiQQERATOR QEI(S I T'f g:a/cm

.FIGURE 3. 4-6 K f As A FUNCTIOt~ OF C-C SPACING POISON LOAOING At/0 ENRICHMENT FOR PMR SPENT FUEL RACK

0. 96 iv,vI' C-C SPACING 0.94 POISON LOAOING 0.92 EWR ICHHEHT

0. 90 0

~ 88 Ov86

,'CHHENT M/0 3.4 (It;C~)

10.0

)ING (gm 210/cm

)

0.01 3.9 10.5 0.02 4.4 11.0 0.03 NOTES:

'.FOR ENRICHMENT CURVE, 0-C

=

SPACING CURVE,. M/0 = 3.9, LOAOING W/0

= 3.9,

~,h,c, e-LOAOING- = 0.02 LOAO ING

= 0. 02 C-C

=

1,0. 5"'

~

}

y

~

~

(

~

~

~

~

~

~

I FIGURE 3. 4-7 HEUTRGH+SL. IPLICATiQR FAC rOR, W~T=,

AS. A FUNCTION OF FUEL ENRICHMENT

~.:

ANO POISON S-10 LOAOIi%

FOR SMR SPEHT FUEL RACK i

~

~

I

~QLSQN LOADING II

~

0. 94

~235 a4RicwzÃi:

ENR I CHMENT U N/0

2. 70 POIcGH GM ti--7VJ Z00 BOOTES:

FOR

~

FOR FOR I

'.'20 I

I

0. 5103 I

ENRICHMENT CURVE, B-10 LOADING = 0;6'103 PO I SON LOADI HG

CURYE, EHR I CHMENT

= 3, 20 BOTH. CURVES, THE "C".HTER-TQ-CENTER.PAC I iG I

I

3. 70

0. 0153

I

(

I 4

a'

~...

~

~

~

~

~ L- ~

~

~

"::.:.. FIRIRE 3..4-8 ilEUTROH.~CLTIPL'ECATI(2t.FETOR- $Mfp }

. ':AS P FUNCTION GF. STORAGE CELL CENTER-ITO-CDTER SPACING miR ~NT. ~~~~C:

I I

I I

I l

~

I

~

C r

~

i

~

~

Q. QQ I

~

~

~

NiiiiNii SPACINSt c 'b,c) c.'

N(NIVAL SPACING 4.ib,C.) C.

I

~I~

I r

I r

~

~

. l 1

i

~

I

~

~:

I I

I 6.3 6..2

'6.'4 6.5 6

6 INCHES SPACING

=

l CELL 'CENTER-TO-CENTER SPACING

( I NCHES

)

NOTES:

FUEL ENRICHMENT = 3,20 H/0 UZ35 f'

'OlSON LOAOING l= O.OI03 grn-8'CN

• OUE TO "CHECKFR60ARO" DES'IGN.'1'INIHUH CELL