ML061880458
| ML061880458 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee  |
| Issue date: | 06/19/2006 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Julian E | |
| References | |
| 50-271-OLA, ASLBP 04-832-02-OLA, RAS 11812 NEDE-24154P, NEDO-24154 | |
| Download: ML061880458 (10) | |
Text
Supplemental Safety Evaluation For The Uneral Electric Topical Reaport qualification Of The One-Dimensional Core Transient Pzdal For Boiling Water R-2actors Volwas 1, II and III Prepared By Reactr Systems Branch, DSI cxiii!cxiv
-The Safety Evaluation Report on the ODYN code (Reference 2) is primarily an evaluation of the calculational =del vith little discussion of implementation requirements. Reference 3 provides the information required to bridge the gap between evaluation and implementation. Specifically, there are eight items covered in Reference 3; these are:
- 1. O0Yh Option B statistical adjustment factors,
- 2. Control rod drive scram insertion time conformance procedure for plans licensed under ODYN Option 5,
- 3. Unc2rtainty in ODYN pressure calculations,
- 4. ODYN model temperature limits,
- 5. UncerUainty In subcooled boiling =del,
- 6. Description of electronic hydraulic control modal,
- 7. L'lstinog of 00,7M input vcl"ILableso S. Czmparison of minimum critical power ratio oper&ting limits est-ablished by REDY and OYN.
Each of these items is discussed below.
item 1. Statistical Adjustment Factors Page 111-5 of Reference 2 allows two statistical approaches; one is a plant-specific statistical analysis and the othar is a generic analysis for plant groups (e.g. BWRP/2, 3, 4, 5, 6) and transients. The second approach involves the establishment of rgneric ACPR/ICPR adjustment factors for groupings of similar-type plants which can be applied to plant-specilic ACPRI/ICPR calculation from the 00Th licensing topical retort (LTR) deterministic approach.
Reference 3 provides the statisticl adjustment factors for the three transients hich are normlly limiting transients (load rejection or turbine trip without
Ax %be e--?1t~vz @f eacl sumil-Az11ee tast pafra in oeýpJiance I.-th tb techtical atcl-ficatict surwvi11aoce r.'qii rmos, the average value of all turvoillaince data at the 2C0A imserziou p~1ton gaterated lao tie c~ycle to
&;a. Is to be tezttd az tie 5Z esgpificAtce level agzli:t tha distrbuatizz asszoe inthe ODT. a&alsaz. The 3aV"1Z.Lcd Inforsut~io *hi4**aCb Platt USIDS thiS PT"JT WillazLe2sVe to TrOtAdt thvuihOvt tb& fuel C-YCJ2 JS The U~kr Of &CtIV4 aCO:?o iC-dS 2M.A~trd fOV .elb US-'.ila~
(at
. f--:::
uastisla t t~a 1M Mis d=0t&4 1 SM 1th IthfttsLa tdeoa ) sod the average ac~az tiz too s~ 20:. Itiantat "stiza fZT the ac%1Y* rzds nesslarad loZ tes t I ( I). Thae .uatioz zaad tv s ulxta~ the ogtarll. a~va:aze of all :!%e Scr datB generated to date 1z the C7:lae is:
Ube=
InI lai active Tossas13td todate Inthe cycetoa comply Ltth Tapts:iricl crar .adflxn~c9 requiraaer::.
cxvii
-I, t+/-i for o Tazt"'M iIdar Ot+/-tl=' 3, w7 L lso be ell:r*a, ed .ithe l~i=-
ai~*Ac(2-6)
The Talatir abtitI@V twe CU ezftICILt, A. cud the -*.*=t of ouweallIa29 e"M~cien decrtases, as doeS the acca~tance g itarisn, 'T20 MU;. tht acT2--
ipeed cr!:ie:1 12 tbeinZ titht"8ed As the L7CyCl'PTOZ7."38, based On the as thlat, es w=.& rrat tlovIh diLa h$em- a,*viltble du=rIn the vycle, the
=goraft7 I the toazz value ezlc~1c:1a- sheuli decrease.
We find the scr= Insertion tIme conft'rance procedure to be acceptable, Item 3. Uncertainty in ODYlfProessure Calculations Page 111-7 of P*fertnce 2 states that if SE can denmnstrate that the uncertainty In calculated pressure is sml1 (e.g. by a factor of 10 or more) relative to the tias In deterraining AVE vessel oveipressure limit, no addition of uncertainty to the calculation's of pressure Is neded. A sensitivity study varying ODYN Input paramters ever the range of Table 1 of Reference 2 shows the RMS Uncertainty in the peak vessel pressure tU be 11 psi. GE estimates the bias In the ASE czde to account for the material uncertainty to be approximately 310 psi. Therefore, there is no need to account for pressure uncertainty in cx+/-ix
Item 6. Description of Electronic Hydraulic Control Model An early draft of Relfretice 2 stated aWherein electronic hydraulic controls ara used in the design, the model used in selection of initial control setting shall be submitted for staff review.2 This statenent was made because Reference I provided information only for the mechanical hydraulic control.
GE claims that there is no functional difference between the two types of control. However, they provided a description of the model in Reference 3.
We agree with the GE claim that there is no functional difference between the t-z types of control.
Itemf 7. Listing of ODYN Inout Variables Page III-10 of Referance 2 states "Listing of important input vzritbles such as H13te~d In2 Tablo 1V tri initial plapt P-srme~- Includlng but flpt liimit-ed ti control -yettmx ch ctristlcs as depicted in Figures 4-13 thriough 4-16 of NEDO-24154, vol. 1, b&ut with nuzmerical values przvided should be provided with each submIttl. The Initial control system characteristics, including the model used in the selection of initial settings, shall be defined and substantiated In terms of the design basis for each control system of the plant.' Item 7 of Reference 3 lists typical values of these initial parameters which may be Included by reference intz individual plant submittals provided tbevalues are appropriate to the individual submittals.
,itam 8. Cometrison of*14CPR Operating, Limits Established by REDY and ODYh The Staff requested GE to provide a comparison of CPR operating limits based on REDY and ODYN prediction. The pur;ose of such a comparison was to cci
The cents for t~4.cb a=T' ha ettc g.oIlfied and approved are listed it 28afeeace 1, Voli.i 3, ad include tlý* felov'tr+/-a: (1) foe~dvaar Cutrziar ffluta-mazi..= dt~.ad; (2) presuazaT ragulator failure-closed direction; (3) Zen-orator laad rajocticz with and vitbout by72ss C'p@?atlco-; (4) m~l steanuliz.e 1.3olatioz valve closuare (trip.scr= and flux ecra); (5) loss of cznen'ser vuacu=; (6) turbine tri+/-p -v:hand without brnass; and (7) loss ofa1L-pcver all grid comions. CZ proposes tha O;-lhl the followin :?hrte aventz be 72aýQcrtad for reload suabudtt&2s OT 5Sfet7 U52!75is, reppon Tre'i~jls:
gen~erator load roe~o/ubz trip -itbout Ibypas: (whicheve Is 2121i:ng),
fiedvater cmtn~ollaT failure-saximu= de~and, &ad asil aezzalint i~clation ;A:V2 alosure-flux scram (tz satisfy AMC so:da pressure requirrt~ets). These A-.* :be moe prassuTlA:at1zt events 7presamtIy included In 7tlc~d subaltuzls, &adra~else tbt CV=!.B3t&C7 in the 0=T2 an~d Z=T revults. The ewe~tt "te icluaded it h These e~vents Irv CCs:!A erub7l ess severe %him thi t-:.-emnt9 %emwtfth :%.2 blp-aS3 Vstme 11; assi.ed to fail. Ty~lezl turbine tm.-ass capaciti~es 7Sle frao 23-40: of rated Zteanflciu. This t~pass czpacit7j results In ca sd erzbly imilder theo-ma enid everpressurizatlot event.
21 Pressure Regulator Failure - Closed Dtrection The sanadard event evaluated im SOR a17zly- Is to* it wbich the c*=o2.+/-l!=
-pressure regulazc is assumsd to fail In the closed directiciz. 'Under thes:
fzilurv ec~dti:vst the tackup ?egulatar takes ever contrl of thetubn
- 6ftialat valve~s, Travestin a-.y serious tr"- 1=:. The d rh t~c s li~d and sizilar to M preSZU70 Ott Point change itb no significant? reductic-.5 Of fj-l t-uer-l =rt-S AzzT.!
Wihomo In the MsA, 0h-it ricarm ts =2d-Z2 loss scvnot h~at the goczrato? and rvrbime tripz vithout t-fpass.
Cexii!
- 11 ° The staff agracs with the GE assessment of tha relative severity of th2 trtnsients listed. Therefore, the following events should be reanalyzed with ODYN for plants which have analyses of record using REDY:
- 1) generator load r-tjection/turbine trip without bypass
- 2) feedwatar contr-ller failure maximum demand
- 3) Pmin staam line isolation valve closure-flux scram.
If for a particular plant another event should be more limiting than those just listad, then the other event should also be reanalyzed with ODYN. For the new plant. with transient anal.vses supplied by GE, all of the events listed in Table 3 of Reference 1 should be analyzed with ODYN.
c0c=v
Table I.
SM-w= F 'a-F STZX7Jp,.IAL AnJVS-.w-LT ZAC-.OU~ (LCV3IC?)
Grou-jings LR TrIc 3?* ~,fl?
31"I 2/3 !O2C --0. 006 -0.016 3WR 4/3 W/o n.7 - O -0.*039 -0.009 WR 4/5 VIC RPT - M -Q..009 MM -,/S W/nT -D.
RMIE 4/3 FT MX .,a.001 +0.026 I.,1
- Wthte e=captiat of TUC? oT PUT evwatz, this s*.a of adjust~zt iactc:5 wilbe applicd to mll pressuriztion even~ts a~nalyzed withb the O=Y code to establish the ORl operating l+/-i.+/-:, eimcm they typlcally Lirolve generatcr a: rurbiz crtpa*
,*--vii
%0.0 13 21 Lo~
Aai*ý c AM MSXI¶~I "TA L= PF31nIl m CMF2 5:~ S.+/-V+/-i~lc-cs Coaefic.4= (A) vs. SurVc+/-11act Deca Im Cycle cxxix
GENERAL ELECTRIC U.S. Nuclear Regulatory Commission Page 2 adjustment factor (AF) to the ratio of the calculated values of ACPR and ICPR (aCPR/ICPR)c:
(CPR ne(w = CPR (T*-C-Rnew = MCPRTc + AF This equation can be simplified to:
ICPRneW SL I - rtE(CPR)C 7,-pF~c + AF]
Where SL = Safety Limit MCPR It should be noted that in both the Option A and Option B cases, the ICPR is defined as Safety Limit plus &CPR for the event being analyzed.
if you have any additional questions or comments, please contact me or H. C. Pfefferlen on (408) 925-3392 of my staff.
Vary tr'uly youJi's, R. H. Buchholz, Manager BWR Systems Licensing Safety and Licensing Operation RHB:sem/1158-59 IF cc: L. S. Gifford M. W. Hodges
~,Cd / C=c0ci