ML18219E121

Light Water Reactor Branch Forwards Branch Technical Position Cpb 4.3-1, Westinghouse Constant Axil Offset Control, Which Will Soon Be Included within Standard Review Plans

ML18219E121
Person / Time
Site:	Cook
Issue date:	10/28/1975
From:	Kniel K Office of Nuclear Reactor Regulation
To:	Tillinghast J Indiana & Michigan Electric Co, Indiana Michigan Power Co, (Formerly Indiana & Michigan Power Co)
References
Download: ML18219E121 (13)

Text

f'

( ~--f

( ~ ~ h"

~

4 hfdf FcCket tlos:

5'0-316 8 s e I~~

Tn8iana -r, f)ichioan Electric Ccnpeny f I'h Xndiana 8 Hichiom Power Cc..pany AT&2 Yr. Jcbn Tillincbqst Vice President P. 0. Fox 18 Pcvliro Creen Station ITep York, Kqv York 3C004 leren: I'+nt The Con;,iscion has recently establishm~ a basis for han8lira licensee su&ittals for Pestinohoum reactors which propo o util'izinq Constant Pxial Cffret Ccntrol (CACC) with ~aking factors los;er than 2.32 or k'enB v<Mer than +5%.,This basis is in the fort"of a F'ranch Techni-cal Position, CPB 4.3-1, and >~ill soon Lo include8 Mithin the SterxarB Fevicw Hans.

Pince this pcaiticn ray affect ..uhrittals ~Sich you have recently raCe or conterplz.to v:akino it is forwardal herewith for your inform"tion.

.hou38 you chtoarine thT-t rodificaticn to a sub'ittal pry ently Let dine before the Comt.ission is reouireo, forwar4',eo a econ <<"." practicablo so that ve e'ay complete our review.

it is regle. ted that tie revision ke Sincerely, Karl Bnie3, 0;iaaf 1'it ht Voter &e~ctorr: Pranch 2-2 Fivision of Reactor I.icersing F. clo.,ure:

Pravcb Technical Ec"ition, CKF'>.P;3 ccs ~/n:.e3.ordure:

.ee v.rxt p"m.

044IC4+ .XRXE.........,.......,........,.......UIt.R.2.-...2 '... -..2..

4VIINAMCW ,.......,...,.....,....,......;,'RABenedi.ct.: ...,.......... Kniel.

h DATCW , 10/,k../.75... Zo./4C/..7S.

FOITC ~318 (RCT. 9-53) hECM 0240 4 U 4h OOVCANMCNT PIIINTINO OCCICCI I474 444 I44

O. i, 2

ccs:

Mr. Robert Hunter Assistant Vice President American Electric Power Ser vice Corporation 2 Broadway New York, New York 10004 Gerald Charnoff, Esquire Bruce W. Churchill, Esquire Shaw, Pittman, Potts 5 Trowbridge 910 17th Street, N. W.

Washington, D. C. 20006 Businessmen for the Pu$ 1ic Interest Suite 1001 109 North Dearborn Street Chicago, Illinois 60602 DISTRIBUTION:

Docket File NRC PDR Local PDR TI C LWR 2-2 File VAMoore RHeineman WMcDonald NNXXXX MWi 1 l i ams RKlecker ELD IE (3)

RABenedict MService JStolz ASchwencer KKniel JPanzarella ACRS (16)

T. Noyak V. Stello D. Ross bcc: JRBuchanan and TBAbernathy OPPICC~

URNAMCW OATII W Porm AZ 318 (ReT. 9.33) hZCbf 0240 4 U. 8, OOVERNMKNTPRINTINO OPPICIU IOT4 OXO Ide

LI

~ J

~ .. 1 ri n lf P

I I7 IJ

%L CS v UNITED STATES w~UCLEAR REGULAT&RY COMMISSIO i WASHINGTON, D. C. 20555 Docket Nos: 50-315 50-316 October 28, 1975 Indiana E Nichican Electric Company Indiana s Michigan Power Company ATZÃ: Nr. John Tillir.chast Vice President P. O. Box 18 Bowling Green Station New York, New York 10004 Gentlemen:

The Commission has recently established a basis for handling licer.see submittals for Westinghouse reactors which propose utilizing Corstant Axial Offset Control (CAOC) with peaking factors lower than 2.32 or N band wider than +5%. This basis is in the form of a Branch Techni-cal Position, CPB 4.3-1, and will soon be included within the Standard Review Plans.

Since this position may affect submittals which you have recently made or contemplate makinc, it is forwarded herewith for your information.

Should you deter'iodine that modification to a submittal presently pcr.dine before the Corrmission is required, it is requested that the revision be forwarded as soon as practicable so that we may corrplete our review.

Sincerely, n

Karl Kniel, Chief Light Nater Reactors Branch 2-2 Division of Reactor Licensing

Enclosure:

Branch Technical Position, CPB 4.3-1 ccs w/enclosure:

See next pace

'0

.0 4 +

ccs:

Nr. Robert Hunter Assistant Vice President American Electric Power Service Corporation 2 Broadway New York, New York 10004 Gerald Charnoff, Esquire Bruce W. Churchill, Esquire Pittman, Potts 8 Trowbridge 'haw, 910 17th Street, N. W.

Washington, D. C. 20006 for the Public Interest

'usinessmen Suite 1001 109 North Dearborn Street Chicago, Illinois 60602

i'

'CH TECfKICAL POSITIO'A CPB 4.

NESTING)<OUSE CO%START, AXIAL OFFSET CO.'ASTROL (CAOC)

BACKGROUND f

In "connection with the'taffr review of l!'CAP-81SS (17xl7), we revicwcd and accepted a scheme developed by l'i'cstinghousc for .operating,reactors in such a fashion that throughout the core cycle including during thc most limiting

~

power maneuvers'he total pea):ing factor, Fq, will not excccd the v..luc consistent with the LOCA or ot)icr limits'!g acci.dent analysis. This operating schcn called constant axi <1 offset control (CAOC), involves maintaining thc axial flux difference <<it}!in a narrow tolerance band around a burn!!p-dcpendcnt target in in atte. pt to mininizc'the variation of.thc axial dis-tribution of xenon during plant nanc:!vers.

I Originall>'carly '7i)), thc r!aximum allo!;able Fq (for LOCA) was 2.5 or grc<<tcr.

Later (late '74), when 'llccdcd c)la llgcs werc made to the f)CCS cva]!!:!tion r!odcl, 1'~'csting<<ouse, jn oidcr to rect physics:in<<lysis corn!!itr:.ents to al} its cus-

, tomcrs at i'irtual)>'he same t.i::!c did a g<rneric an<<l>'sis (onc d<.si~ nod to suit a spectrum of opcrati:!g:!n<l soon-to:bc-operate!g reactors) and showed that nost plants could meet the requirements of Appc;!<!ix K and.CF)'0. )6

'(i.e., 2200oF pca); clad tempeiature) if )'~ < .32. Also, l"esfinghousc s!!ow<d that CAOC procedures employing a + SQ target. band would limit pca); ):q for 'e,.:

   ~

of these reactors to less than 2.32.

     )!)e recognized at that time, however, that not all p)ants needed to maintain I

Fq below 2.32 to moot. FAC, or, needed to operate within a + 5'an<I to achieve Fq < 2.32. In fact, Point Beach was allo!.'.cd to opcratc with a wider band thc )i'isconsin Electric Po<<cr Company denonstratcd to our. satisfaction 'ecause t}!at the reactors could be nanc<fvcrcd within a widci band (+6,-9"-') and still hold Fq bclo<<'.32.'i'e fully expected that in time most plants would have indivi<lual CAOC <<nal>'ses and procedures ta'ilorcd to the requirements of their plant-specific ECCS analyses.

                               ~

Therefore, whon we acccptcd'AQC it

                                                                    ~

was not just F~ = 2.32 and a + S~o band width we wore approving, but'the CAOC methodology. This is analogous to our review'nd approval of ECCS and fuel pcrformancc evaluation models. The CAOC nethodo]os, which. is described in )"CAP-S385 (Rof. 1), entails (1) establishing an envclopo of allocd power s)iapcs and poi'er densities, (2) devising an operating strategy for the cycle which maximizes plant flexibility (nanouvcring) and minimizes axial power shape changes, (5) clo.",on-strating <)iat this str..tcgy i ill not result i>> core conditions th t violate the envelope of permissible core power charactoristics, and (0) de,.onst; ating that t)iis po>>'or distributioi control schono can bc ofl'ectivcly su~ervisccl i'it!i out-of-'coro detectors. l'icstinghousc ai gucs tliat point 3, above, is achic:vccl by. calculatin<! a)) of the load folio>>'aneuvers planned Cor thc proposed cyc)c ancl s!ioi;ing t)iat thc maximum poi;cr <lcnsitics cxsccto<l arc within limits. Those calcu)ations arc perForncc) i;it)i a radiai/axial synt!icsi's mct)iocl i<hie)i )ias b<<cn shoi;n t:o prc<lict conservative poi'cr <lcn. itics>>!i<<n compared to cxpoiii"..<<nt. !;".iilc: icc

    )lave accepted CAOC on tlic basi s of t)iosc ana lyse s, >>c liavc 'i iso re<!i! i rc d t!iat po>>cr distributioi s bc ncasurcd t)irougliout: a number oF representative (Fro-clucntly, linitin<.) maneuvers oar]y in cycle lifo to confirm tliat pca):ing facto>s are iio grc:itcr tlia:i i>cclictc<!. ldclitiona])y, >>e aro sponsorin~ .".

scrics of calculat:ions <<t DXL to chccl: aspects of t: he t'i'cstinl,)iouse ana]ysis. The'o>>cr distribution LORICA). noasurcmcnt: t:est:s dcscribcd al)ove will, of course,

                                                                        ~

( automatically rclatc incoro and cxcorc clctcctor .responses, and thereby valiclate that; po>>er distribution control can bo managccl >>'it)i excoro detectors. 8)BZC) 1 T):C) VOSI')'10'8 11'hencvcr an applicant or liccnseo proposes. CAOC for other than Fq = 2.32 and hX = +S'e is cxpcctcd to provide: Analyses of I:~ x po>>cr fraction showing thc maximum 1'q(") at po>>er levels

 ~ \      'up to 100"'nd DNB pcrformancc with allo>>od axial shapes relativo to t)io design, bases for ovorpo>>er and loss of flow transients. 'Thc ciivclopc of

    '4

~ 'f

                        ~                  .....

these analyses must be shown to be valid for

                                                              ~

al'1 normal operating modes and anticipated roactor conditions. (Seo Table 1 of Reference 2 for the

    .cases which must, be analyzed to form such an cnvclope.)

A

2. A description of tho codes used, how cross-sections for cycle >>ero deter-mined, and what Fxy values were used.

3. A commitmcnt to perform load-follow tests wherein Pq is dotermincd by 1

taki>lg incorc maps during the transient (:iOTE: Ii'cstinghouso has outlined for 'both tho NRC staff and thc ACRS an augmented startup test program designed to confirm cxpcrincntall> thc pr dieted po>>cr sh.pcs. Thc details of this program will b" .disclosed in a'oon-to-bc-issued l"CAP rcport. Thc tests will bc carried out, at scvcra] rcprcsentati:c - both !5xl5 ancl 17xl7 - reactors. l':c luv'c endorsed those tests as has the ACRS in its Junc 12, 1975 Diablo letter. In addition, for thc near term, wc plan to require th ~t those licensees idaho propose to depart from thc previously approved peal;ing factor and tar<,'ct band width p'el form slmi)ar tests, precise!y which ones to bc doter::iincd on a case-by-case basis, to liroadcn our confidence in analytical methods by cxtcnding thc comnarison o! prcdiction>>>>'ith mcasurcmcnt to include morc and morc burnup histories.) RE!:EP.riCE

1. T. hlorita, ct cl., "Power Distribution Control and l.oad Po) lo>>in" Proccdurcs," KCAP-S:!03, l':cstinghousc Electric Corporation, S ptcmbcr 1974.

I I (Hd..Note - l'i'CAP-S403 and -SSS5 are .thc non-proprietary and proprietary versions of the same document.)

2. C. Eichcldinger, Nestinghousc Electric Corporation, lcttcr to D. B.

Vassillo, U.S. Nuclear Regulatory Commission, July 16, 1975'.

e,

      ~    ~

C' ~ ~}}