ML19246C393

Forwards Summary of 790614 Steam Generator Meeting in Silver Spring,Md to Review & Assess BNL Experience in Modeling U-Tube (Ustg) & once-through Steam Generators

ML19246C393
Person / Time
Issue date:	06/25/1979
From:	Zuber Z NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Patricia Anderson, Fabic S, Tong L NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
NUDOCS 7907240480
Download: ML19246C393 (40)

Text

{{#Wiki_filter:PBA /[ [o, UNITED STATES y g(f(,g NUCLEAR REGULATORY COMMISSION gg j WASW NGTON. D. C. 20555 s +.,*****/ JUN 2 51979 Those On The Attached List Gentlemen: Enclosed are the minutes of the Steam Generator Meeting held at the NRC-Willste Building, Silver Spring, Maryland, on June 14, 1979. Sincerely, N IrW N. Zuber Analysis Development Branch Division of Reactor Safety Research

Enclosure:

as stated s01 7t 9 07 24 0W N

Addressees of Letter Dated L. S. Tong, NRC/RES S. Fabic, NRC/RES P. Andersen, NRC/RES Consultant Y. Y. Hsu, NRC/RES W. Lyon, NRC/RES L. Shotkin, NRC/RES Z. Rosztoczy, NRC/NRR N. Lauben NRC/NRR F. Odar, NRC/NRR L. Phillips, NRC/NRR R. Curtis, NRC/RES P. Wood, NRC/RES W. Kato, BNL P. Griffith, MIT 3h

MINUTES OF THE STEAM GENERATOR MEETING Place and Time: NRC Willste Building, Silver Spring, MD, June 14, 1979 Attendees: See Attachment 1

Purpose:

1) To review and assess BNL's experience in modeling U-tube (UTSG) and once-through steam generators (OTSG)

2) To review available experimental data and phenomena relevant to steam generator transients.

3) To select models for improving present capability of codes to simulate steam generator transients.

Agenda: The agenda of the meeting is shown in Attachment 2. To facilitate the discussion and selection process the speakers were asked to

1) Review and assess present capability of codes to model steam generators 2)

Identify problem areas and rank them according to importance

3) Suggest metnods for resolving them 4)

Identify and rank needs for further improvements.

== Conclusions:==

1) Steam generator calculations needed by NRR are enumerated in Attachment 3.

These calculations require of codes to have the capability to model: A) On the Secondary Side: i) Slip ii) Phase separation - level calculations iii) Various modes of heat transfer with and without phase change iv) Recirculation (including natural circulation) v) Auxiliary feedwater (including effects on natural cir ulation in the primary side) vi) Flow mixing g vii) Stability with load changes }h viii) Control, safety and protection system NhY ~ ~ gq9er 0 4

, B) On the Primary Side: i) Parallel channel instability ii) Interr tions during natural circulation iii) Effects of noncondensibles iv) Critical flow through long tubes for tube rupture.

2) The IRT code under development at BNL, is a fast running code originally intended for calculating single phase flow transients in a PWR.

The code is based on the homogeneous, themal-equilibrium model and solves the continuity and energy equations. The momentum equation is not included in the code. Consequently, with exception of items iii) and viii) in Group A), IRT cannot model any of the phenomena and processes listed above. 3) In order to attain high computational speed, IRT uses large control volumes. This introduces numerical instabilities whenever large variations of thermal conditions occur within a single control volume. To remove this instability, BNL proposes to use profiles for enthalpy (see Discussion for details). According to present schedule, this modification of the code should be implemented by the end of Ncvember 1979.

4) NRR (F. Odar) stressed the need to model the effect of auxiliary feedwater which is introduced around tubes in the upper section. Since IRT does not model phase separation, BNL expressed a concern that numerical instabilities will be experienced if cold water is to be injected in the top control volume.

To resolve this question it was agreed to introduce water uniformly along the steam generator. If numerical instabilities still appear, then as a " bottom line" simplification, BNL is to introduce the auxiliary feedwater in the bottom control volume.

5) Seven basic problems in modeling steam generators were listed by P. Griffith (see Discussion).

Of them, the most important is concerned with modeling flow maldistribution and associated flow instabilities among tubes. These phenomena which occur at gravity dominated flows, are of particular importance to calculations of natural circulation. A need was identified to obtain data on this effect from experiments conducted with a condensing mixture flowing through several U-tubes in parallel. 363 105

, Discussion A. Steam Generator Modeling - NRR Assessment and Needs The presentation was made by Dr. F. Odar. He informed the participants that NRR uses IRT for fast running calculations of FWR plant transients and LOCA. However, he stressed that the UTSG and 0TSG models in IRT are rather crude and emphasized the need for improved code capability to model steam generators. He enumerated the type of calculations that NRR has to carry out and listed code requirements which must be met if these calculations are to be performed satisfactorily. Both the type of calculations and code requirements, are listed in Attachment 2. B. BNL Presentation BNL's presentation dealt with the following topics: 1) IRT UTSG model 2) IRT OTSG model

3) OTSG modeling improvements

4) SG Mark II model

5) Experiments for SG model verification The handouts covering these topics are reproduced in Attachment 3.

1) IRT UTSG Model M. Levine described briefly the IRT code and its UTSG model. The code is based on the homogeneous, thermal equilibrium model. It solves the continuity and energy equation explicitely and omits the momentum equation. Consequently it cannot model a) phase separation b) level tracking c) natural circulation d) thermal nonequilibrium phenomena, such as injection of cold water in a vapor superheated region. }h \\b

4 On the primary si@ 'he code uses Dittus-Boelter correlation for the heat transfer coefficient, whereas on the secondary it uses the Jens-Lottes correlation. The entire secondary side is considered as one control volume. However, the length of the heat transfer area is determined from the intersection of a quality X, specified by the user, and the assumed linear quality profile (see illbstration in Attachment 3). 2 IRT - 0TSC Model C. Hsu described the present status of the IRT - OTSG model. The basic equations and heat transfer correlations are shown in At:achnent 3. The OTSG model has the same shortcomings as those enumerated above for the UTSG model. Present problem areas of tt 'TSG model, identified by C. Hsu were: a) time step control b) steady state initialization c) auxiliary feed water injection d) steam generator downcomer modeling e) recirculation through the aspirator. The last three items stem from the inability of the code to model phase separation, themal nonequilibrium and to calculate momentum balances along the loop. The need to improve the steam generator downcomer model was confirmed by comparing calculated pressure changes on the primary side with data. The discrepancy was attributed to the downcomer flow rates which affect thermal conditions on the secondary side. To improve calculations, BNL has introduced an overall momentum equation for computing the flow frcm the S.G. downcomer to the central section of the secondary side. This improvement will be implemented by the end of July 1979. W. Lyon observed that thermal conditions on the secondary side are affected not only by the flow rate but also by the enthalpy. Consequently, an improvement is needed in modeling the energy flux from the S.G. downcomer to the secondary side upflow section. This entails the modeling of the steam-water mixing at the aspirator. N. Zuber questioned the method used 3bb

, to calculate the flow rate through the aspirator and observed that the term W, should not appear in the equation used to calculate this flow. R The problem with auxiliary feedwater arises because of the fact that cold water is introduced around tubes in the upper section. Consequently, to model this process correctly, cold water should be injected in a top control volume that is originally filled with steam. Since IRT does not model either phase separation or thermal nonequilibrium, it cannot model this process. BNL expressed great concern that if they were to introduce cold water in a top control volume, the code would experience numerical instabilities. F. Odar suggested that, in the code, the injection of the auxiliary feed water should be distributed uniformly along the steam generator tubing. If numerical instabilities still occur (because there is not enough water to completely fill the control volumes and cold water will be mixed again with steam), then as a " bottom line" simplification, water should be introduced in the bottom control volume. 3. OTSG Modeling Improvements IRT uses large control volumes in order to achieve high computational speed. This introduces numerical instabilities whenever thermal conditions change drastically within one control volume. Since in the OTSG model, the heat transfer coefficients are flow regime dependent they can vary greatly in magnitude from one regime to another for example, from nucleate to film boiling. Coasequently, with large control volumes, the OTSG model can experience ldrge changes of energy removal, from one time step to another which introduces instabilities. In order to alleviate this difficulty, BNL has proposed to introduce spatially linear profiles of enthalpy. The method is described in Attachment 3, and bears similarity to the concept attempted in the THOR program. According to present schedule, this improvement is to be implemented in IRT by the end of FY 79. 4. S.G. Mark II Modeling W. Wulff described longer range plans for developing a steam generator model that would meet NRR's requirements. The model is described in.

, S. Fabic noted that at the present time, WRSR does not have plans to develop a new steam generator code because the fast running version of TRAC scheduled for completion by the end of CY 79, should meet NRR's requirements.

5) Experimental Data Needed for Model Verification P. Saha reviewed available data on steam generator steady state and transient performance, and suggested experiments which would provide additional data for code assessment.

The details are also given in Attachment 3. C. MIT's Experiments P. Griffith briefly described the results of experiments conducted at MIT for the purpose of assessing the effect of flow maldistribution on two phase circulation through inverted U-tubes. The experiments were conducted with air-water mixture flowing through four inverted U-tubes connecting two plena The most significant result revealed by these experiments was the existance of two regions; one stable, the other unstable. In the stable region, the mixture was flowing through all four inverted U-tubes. Whereas in the unstable region, the mixture was flowing through some of the tubes while the others were starved. This phenomena depended on flow rates and appeared when the flow was gravity dominated. Consequently, it is particularly relevant to modeling steam generators in the natural circulation mode. On the basis of these experiments, P. Griffith suggested seven basic problems whose solutions should receive top priority; these are:

1) Find the unstable boundary delineatir.g the region of flow maldistribution

2) Determine plenum flow distribution

3) Establish a calculation scheme for ccnnecting plenum flows to tube ficws

4) Detemine heat transfer coefficients for downflow

5) Determine effects of thermal stratification on heat transfer coefficients

6) Determine the effect of multiple steam generators connected to the vessel

7) Detennine heat transfer regimes in tubes during downflow.

Peter Griffith agreed to discuss these topics in more detail together with available experimental data, at the forthcoming Steam Generator Workshop. 3()3 l

Attendance S. Fabic, NRC/RES P. Andersen, NRC/RES Y. Y. Hsu, NRC/RES W. Lyon, NRC/RES L. Shotkin, NRC/RES R. Curtis, NRC/RES P. Wood, NRC/RES N. Lauben, NRC/NRR F. Odar, NRC/NRR W. Kato, BNL M. Levine, BNL C. Hsu, BNL J. Jo, BNL P. Saha, BNL W. Wulff, BNL ^t) \\' 93

Steam Generator Meeting: Agenda NRC Willste Building Room 106, 9:00 a.m. June 14,1979 9:00 - 9:15 a.m. Opening Remarks - S. Fabic, RES 9:15 -10:00 a.ie Steam Generator Modeling - F. Odar, DSS NRR Assessment and Needs 10:00 -11:00 a.m. BNL's Modeling of U-Tube Steam Generators 11:00 -12:00 a.m. BNL's Modeling of Once-Th-ough Steam Generators 12:00 - 1:00 p.m. Lunch 1:00 - 2:30 p.m. Discussion 2:30 - 5:00 p.m. Selection of Improved Models and Recommendations i k 7) \\ ,) ~

F. Odar's Handout Steam Generator Codes Type of Steam Generators a) 0(eThruSteamGenerator (At least two kinds) b) U Tube Steam Generators Westinghouse (at least two kinds) Corbustion Engineering (at least two kinds)

Purpose:

Audit Vendor Calculations a) Audit Demand Heat Curves used by B&W in OTSG for TMI-2 incident and transient calculations b) Audit Steam Generator Level Calculations in OTSG and U tube generators for transient (loss of feedwater), ATWS and accidents (steam line break accident) analyses c) Audit Mass ard Energy release calculations in steam line break accident - moisture carryover d) Audit natural circulation capability in the primary. This is dependent on the auxiliary feedwater in OTSG and level calculations in the U tube steam generators e) Audit parallel channel instability between the tubes in small break LOCA, SLBA and other tran:'ents where boiling of primary side occurs. f) Audit natural circulativ capability (or interaction) for different flow rates and heat fluxes in a bundle of tubes g) Audit the control, engineering safety and protection system h) Audit steam generator tube rupture analyses (SLBA or LOCA) 7 g \\ ',\\ "

l 2 Capabilities Required Secondary Side a) ilip b) Phase separation - level calculatiens c) All modes of heat transfer d) Recirculation e) Natural circulation f) Steam Separators - dryers g) Auxiliary feedwater (Eventually 3-D) h) Mixing and energy transfer (3-D) i) Stability (OTSG and U tube) with load changes j) Control, safety and protection system k) Effect of non-condensibles

1) Tube recovery - level calculations Primary Side a) Parallel channel instability b)

Interaction during natural circulation c) Effects of noncondensibles d) Critical flow through long tubes for tube rupture \\ \\} 3 f 1 n50)

. - ~...- _~ Full-Scale Once-Through Steam Generator Figure A-1. M AC70. CDOLmi s.LtT 7 1/ " ' ' T x ...,in x v \\ I .t.1. Lt.it st. 5,.6 ' MDhMLi Wi rm a F.cqi . m,... i l l l d' J[ li,'Af ""' . y assiu u, e tte,..'t.

• P I R 'l [, a r p Lt.

..L E, i, >t i tt f t,: :: 4 4 ,,1

.t h (: pml l,,r.

q a3 3 ....,, a %4 q.

• 6 l. 'ep t ;l ky./

u.t ss..oe'.Latts t ..w. 4" +, I / t l .= >:a i.> 4 u.a u.s,. 2,,, N ...a, -n y l ) '! i n e..u. i.a,, n, 1' 6 ,.!-.t.., 5,, ?, a.u s,.s. o, 3 ,a l 8, )! =&p =5 B c m 3 ac%"t f g' [,p j Q t t> 1 x p$ 4 Q ? J ! JNh jklj '.f s Livh $tast.& (2) ,l b dn gf 5 l%, muin .. ~... - 0.... Sawit < t p [ j ":'~?,:"' S!3.%i W%,,,,,,, .h ! t e.t .t. N / ~%.ggjgp @:n ..ni-7.... 6 3 ),' .uno. ->t., N .sn ni 3 y N i. in....i ../ Babcock &Wilcox A-4

~ .~K P ( REACTOR 400LANT INLET NAN 0 HOLE s ,.s y.9 RANIATS y h 'a =, ' SUPERHEAT =_ h _=. REGION FILE ,_ __g n _i U " 80lllHG RfGION CTLilGRICAL 0 BAFFLE [ NEAT TRANSFER "~ 9 REGIONS AT l 1605 POWER l ii' g STEAR ANNULUS NUCLEATE BOILING REGION J_ d j STEAR OUTLETS (2) HAENDLES o AUIlLI ARY FEEDIATER INLET N' FEEDIATER { } SUBC00 LED / INLETS (2) j\\ BOILING l h 7-{j REGION d g D N N S-2 REACTOR COOLANT - A }D t CUTLETS EANIAT p.- ORAIN N0ZZLE MAN 0 HOLE 't 5 \\\\ jg[ f]fffs /: (p rf L: W 4 ONCE-TRROUGH STEAB GENERATOR Figure 5.5 3

[ STE AM OUTLET T0 'fr ' MolSTURE SEPAR ATOR TURBihE GENERATOR I g ll' NANWAY p I w UPPER SHELL . l 'N SWIRL VAN E N0l$TURE SEPARATOR i { I E Q FEEDWATER INLET 5 ANTI-VIBR ATION BARS N, ,4 )I,l0id ( l TUBE SUPPORT 5 TUBE BUNDLE l 21 'llllI E ' P ARTI TION C c I TUBE PL ATE 3 c 5 MANWAY $UPPORT FOOT CHANNEL MEAD s PRIMARY COOLANT -- g P RIMARY COOL ANT INLET OUTLET i -s;p n - - 5 5-4 s a. ,-_-mw

- - ~, c G-u DRYERS l SEPARATORS @! (([0D[ [0[00[ I N M N O. SERVICE REQ'D F- _I:+ 20'-5 " g' O. D. 2 PRIMARY OUTLET 2 ) 1 PRIMARY INLET 1 l /[ 3 3 DOWNCOMER FEEDWATER 1 r 4 STEAM OUTLET 2 5 BOTTOM BLOWDOWN 1 6 ~~ 6 LIQUID LEVEL 8 7 PRIMARY MANWAY 2 8 SECONDARY M ANWAY 2 s 69'-0"M 9 HANDHOLE 2 10 UPPER ECONOMlZER 1 l FEEDWATER l l 11 LOWER ECONOMlZER 1 l4-15'-10" FEEDWATER { l 1[ o, D. "{ ) c==a b ?h ~ 45' ~

• 'l em-s l

2 A* g 4 ] g -lI .[ l i f dd 'd d 2 'd h. d {g' O ! l! l A Vl O-(@- 45' V 9_ \\ DRY WElGHT 1,4?8,900 LB5 FLOODED WEIGHT 2,220,000 LB5 NORMAL OPERATING WT. 1,725,000 LB5 (FULL LOAD) Amendment No. 28 SHIPPING WEIGHT 1,570,000 LB5 May 5,1975 STEAM GENERATOR Rg e

a Bril PRESET.TATI0tl AT SG t'0DELIfl0 f EETI!!G 45 nin. Current IRT U-Tube SG !'odel ti. fl. Levine 10 min. OTSG flodel Introduction it. M. Levine 15 min. Current IRT OTSG !;odel C. J. Hsu OTSG !! ark I itodeling 10 min. Downcomer C. J. Hsu 15 min. SG !!adel J. H. Jo SG t' ark Il f:odel 20 min. OTSG/UTSG

11. t!ul f f 15 min Experiments for SG flodel Verification P. Saha i

l I

e BNL/NRC Meeting on Steam Generator Modelling June 14, 1979 @ \\'\\

T12T llcoi Exc f a o, y.,. gg,Il /gf '*> b!L Ws, k f ) SG > s c' c , cc @pt ^ f) ( ,yv e @^ 9" .,g,3 e 363

ConSerVaboN in a rs m= Xw Volkm e (ht <r) = o eneyy (d4) = 9 1 E uh + v/s Assu me cah,apJ b: b (f)X] .v. e (p,x) 5'olve 6r ji, >Q, d, (or j, 4, x') . UTSG '1-p

4 e e DN8 3 I 1 48 !s,! 4 3 V T S G 'l \\$~

O TSG -1 OTSG Fived n acier lhho e n eO uS Epk L L,1=Ly frc : Encry h< /n<c r p m) co y "rn L h/){nj) Sec : Ann t e ncy; b<hnec Tubes: Eheyy b alave l ~<< g te mp.ymdie>,7 (t4ra ua//) HL Xfc : 5 d odes So/ve r : Eyp/rbef D unco ~ec e f p g, q f(/A) tic w n s hnci4d = 1 f

6. Jfe - OTSG In [SC Foxd nodes sk/l=/v< 3 TJes = Nto Sec. pressue cL%cJ L rk y D,plusi, 7h o (nk + if nu.) i DN8 f on t &prmmc) 4, y ~44 'wer

uitL, nede.

e

IRT ONCE-THROUGH STEAM GENERATOR BASIC E9UATIONS (A) PRIMARY-SIDE: - IT, A (T. - T,,,;) ( T.,)t - Tet (! Y c. 2Wc = et e rc e g (B) S. G. TUBE M.V,,,c. ([ = V A (T. - T,,,.) - % A.s:(T.c- %) s ee re p B 1 1 PRIMARY-SIDE TUBE WALL = + +1-Uri fe FOULING RESIETANCE RESISTANCE 1_ 1_ SECONDARY-SIDE / TUBE WALL h it 52 FOULING RESISTANCE (RESISTANCEj ASSUMPTIONS (A) (%'),a (Tet),a T -- Pt 2 (B) FOR EACH INTEGRATION TIME STEP, Wj IS ASSUMED TO BE CON-STANT FOR ALL THE PRIMARY NODES. THE VOLUMETRIC FLOW RATE,Wj[fj,HOWEVER, 13 DIFFERENT FOR EACH NODE. \\N 2

HEAT _ TRANSFER CORRELATIONS MODE 1 - SUBC00 LED FORCED CONVECTION SIEDER-IATE CORRELATION MODE 2 - SUBC00 LED AND NUCLEATE BOILING THOM's CORRELATION MODE 3 - IRANSITION BOILING MCDONOUGH, MILICH AND KING MODE 4 - STABLE FILM BOILING MIROPOL'SKII's CORRELATION MODE 5 - SINGLE-PHASE STEAM FLOW DITTUS-BOELTER CORRELATION FOR STEAM 1361) '/ 3

_ - 5.,c + q - W, + ( e)z f TWe)Dc i E Ps a [(Yc+s3) 2 Lal Iy Ac - Bz ks (i = / ~ N) = WHERE, FOR EXAMPLE, 1-1 1-1 K; - a; _E 4; At s; - a. L E, B: At = 8'. = n: mz 3 Z-1 E - di-i bc = ( A;.,- Aa) 7; - CT; 0.2 = i Kz = { 4 - 4 _,) kc + d + C 6-,- 4) f W + (Z hFe D f oc 2 2 i-/ + [(Z We)'. - d (2 We)c + ([ dWe)g 2 \\N 363 PODR DE81NL

L I ->- Steam A P Feed Water sec W, h f f A Seconda ry-side Downcomer Volumes U

• DC DC A

Vol. 3 H

== DC A pf DC Vol. 2 - g Water density DC Vol. 1 I h 4 - DC y y (Mass) in

• "f - "DC DC DC DC) d(m h

(Energy) DC ff-NDC DC dt At steady-state condition KW

1. "DC -

"i"i 9 f pf from which X is calculated. During transient, since H DC p DC W,c = r ,,. 9, if6 Sb3 7

3 O a%MnaEM, 0oHC i Do SMo9.?82 a " 8e 3 8 @ a 5 f_o - o U 0 IB 0 e 0 1 6/ 0 1 0 1 \\ / \\ 7 1 \\ ,\\ 2 9 0 si* i ( i 1 \\ ) ,/ 0 t,j s / \\ /, 30 ,\\' 0 ( / P 2 x R ) 4 E 0. S .N' 0 S U R .N I 5 0 Z E I0 N R T I M N P I ,E 60. RE R S0 S E S 1 .C U R 7 ( E 0 3 0 ) VS I .m. I 0 N 1 E 0 ,0 0 e 3 00 0 1 10 0 12 m 0 0 C p y,t ~

PRESSURE, PSIfl as.o eso,a sys.o toca.a sc25.0 to p.o i g.o s.tca.a 1135,a g .o = ,o o D C- -\\N .s. o w O 11 g .c H-iA en M o g e 8-b h <i m 8. Qm me e-e "I z N H .b - mo ",X3 r P1 .D 2 .t C = 1 N a rri i,t O 4 B_ I M b o i 6 .-a s f 3 ,8 - j [ P1 eI i, o a e u v 13 .O ~ [ o q 1I g_, 1 o o 'Q. Y Q \\ Sb3'

t IRT ONCE-IHROUGH STEAM GENERATOR PURPOSE: MODIFY IRT ONCE-THROUGH STEAM GENERATOR TO TRACE BOUNDARIES OF DIFFERENT HEAT. TRANSFER REGIMES. MODEL: 3 TO 5 VARIABLE VOLUMES ~ 2 TO 4 BOUNDARIES '2 FIXED POINT OF TUBE RUPTURE POINT OF RECIRCULATION h TO DOWNCOMER ,2 M0vlNG fB0!LINGPOINT (CHF POINT (?) k ]h)

e LONG-RANGE PLANS FOR STEAM GENERATOR MODELING OTSG E UTSG MODELING NEEDS PRIMARY SIDE SECONDARY SIDE SOLID STRUCTURES PROPOSED MODELING METHODS FLUID MODEL S0'.UTION METHOD REQUIRED PROCESS MODELS ENTRAINMENT/DEENTRAINMENT CROSS MIXING PHASE SEPARATION CONDENSATION 'l

a e e a .f.Cf D. goot.at ,.t ti I B. SPIC I,0. PC.T p...... i i .... o.,< ii.s,.; h\\ 1 4 f.w m s,N M M U!g:g!U.jj ,. : sz,n y -" ..a,m.... i ~. t.... ,n i. gL..l:l'.!!';y;lgrn/ c cJ n, y 7gpn af';i jiW r '.i q g .......,,a .. q....t mi. ,1 n -q W. g q [e, f,,,,,,.... P.,ts i t ..,r... y-z.j 7 g sit u cotte r i,i 1 X....,,, t t. !t st.s..e,,i l j:: i,,p .m..:....a .u, ~1 W . -. u,,, y 3 3, u.t,,.s,c,,, 3 T %Q .,,e.- ,e,,, B a a lqf.g r$ sij ten. s.s,a w C L.'gA. p $ Rn av ::ttirs a M h S,.kBfhk}khbb'f _EFy@niti;h"H p y u u 1 i:

3.. m u

..,v -. e-fi1%$$$ M..,ik @m m ....., s. a,,, x g4,...... ....,a,,. n Bf a..u.,,.o,, s. ne I 1 O) A.ix.a es...i N-la, b w .:.:;r,r-x, s fx --- .n v 'i p \\ -) J N. 1" - ..... J STEAM GENERATOR OUTLINE THREE MILE ISLAND NUCLEAR STATION UNIT 2

100 90 Superheat \\ 80 3 7 70 / x 30 B> b40 A 30 A Nucleate Boiling [ Film ,/ Boiling 0 0 10 20 30 40 50 60 70 80 90 100 Rated Power,% \\ 3-)' h,3 STEAM GENERATOR HEATlHG SURFACE YERSUS POWER T11REE MILE ISLAND NUCLEAR STATION UNIT 2 .,1- ~. ( FIGURE 5.5-5 sc,-

A PRIMARY SIDE FLOW MODEL SINGLE-PHASE LioulD 4 TWO-COMPONENT, IWO-PHASE FLCW (H O AND N ) 2 2 NONHOMOGENEOUS, NONEQUILIBRIUM FLOW (SLIP) FORCED AND FREE CONVECTION INTERFACE TRACKING 1. MIXTURE LEVEL 2. BOILING BOUNDARY (3. FLOW AND HEAT IRANSFER REGIMES) HEAT TRANSFER SINGLE PHASE, LIQUID TWO-PHASE, LIQUID WATER & N 8 WATER VAPOR 2 SUBC00 LED BOILING BULK BOILING J CONDENSATION (EFFECT OF N ) 2 LIQUID ENTRAINMENT ANNULAR - MIST FLOW INTERFACE 6

~~ SECONDARY SIDE FLOW MODEL SINGLE-PHASE, LIQUID AND' VAPOR / AIR IWO-COMPONENT, IWO-PHASE FLOW (WATER AND AIR) NONHOMOGENEOUS,IIONEQUILIBRIUM FLOW FORCED AND FREE CONVECTION INTERFACE TRACKING 1. MIXTURE LEVEL 2. BOILING 3OUNDARY (3, FLOW At4D HEAT IRANSFER REGIMES) HEAT TRMSFER sit 1GLE PHASE, LIQUID ~ TWO-PHASE, LIQUID WATER AND AIR Susc00 LED BOILING BULK BOILING (CONDENSATION, Py<P) 2 ENTRAINMEllT VAPOR (DOWNCOMER ENTRANCE) LIQUID (MIXTURE LEVEL) g;b 3b

9 g O PROPOSED MODELING METHOD FLUID MODEL GEOMETRY BALANCE EQUATIONS INTERFACE EQUATION CONSTITUTIVE EQUATIONS SOLUTION METHOD SPATIAL DISCRETIZATION TEMPORAL DISCRETIZATION & SOLUTION METHOD \\r 3b3

~~ UTS G GEOMETRJ n I 5EPERATOR/ DRYER / f**

• E-PRIMARY StoE h

i, f s o d Q k /

==> ct f b= :> Q / ~ n / d f e- $p g v / f 7 L h h h WA SEcoN DARY SIDE -o O I g \\Jo d n

INTERFACE EQUATIONS 4 1. INTERFACE WITH CONTINU0US FLOW VARIABLES Y{f(Z)) = 0 i cap /ar)/ca%hz) = EXAMPLE: BOILING BOUNDARY 2. KINEMATIC JUMPS mixture AND GAS MASS JUMP CONDITION AND FLOW VARIABLES BELOW AND ABOVE THE INTERFACE. 93

~- SOLUTION METHOD P.D.E. AYT + BYZ SPATIAL DISCRETIZAILOH 1. CELLS WITHOUT INTERFACE UPWIND DIFFERENCING (BNL, RPI) e 2. CELLS WITH MOVING INTERFACE LP MODEL WITH EXTRAPOLATION OF PROPERTIES f, Y AT INTERFACE FROM DISCRETE MODEL. TIME DISCRETIZATION STAND-ALONE PROGRAM MUST HAVE TIME INTEGRATION SCHEME OF HOST CODE (SYSTEMS CODE). \\ [U i

~ REQUIRED PROCESS MODELS 4 ENTRAINMENT/DEENTRAINMENT DROPLETS AT MIXTURE LEVEL DROPLET-TUBE-BAFFEL INTERACTION STEAM ENTRAINMENT AT DC ASPIRATOR CROSS MIXING UTSG OTSG BAFFELS PHASE SEPARATION BAFFEL EFFECTS CONDENSATION SUPERHEATED STEAM & INCONDENSIBLE GASES. O \\

EXPERIMENTS FOR STEAR GEt1ERATOR MODEL VERIFICATI0H 9

B. U-TUBE S. G., o STEADY-STATE AND TRANSIENT'EXPTS. e GLOBAL VARIABLES (SAME AS OTSG) 0 INTERNAL VARIABLES - TWO-PHASE / WATER LEVEL IN SECONDARY - PERFORMANCE OF SEPARATOR (CARRY-0VER AND CARRY-UNDER) - PRESSURE, TEMPERATURE, QUALITY AND VOID FRACTION (FOR 2-PHASE) IN PRIMARY AND SECONDARY - RADIAL DISTRIBUTION OF PRESSURE, TEMPERATURE, QUALITY AND VOID FRACTION IN SECONDARY

3. SUGGESTIONS FOR ADDITIONAL EXPERIMENTS A. FULL-SCALE S. G. o VERIFICATION TESTS IN POWER PLANTS 0 IRANSIENT TESTS (E.G., LOAD FOLLOWING) - MAii1LY TO PROVIDE GLOBAL VARIABLES - INTERNAL VARIABLES AS MUCH AS POSSIBLE B. SUALL-SCALE S. G. 9 CONTROLLED, WELL-INSTRUMENTED EXPERIMENTS IN LABORATORY e SIMULATE ALL POSSIBLE REACTOR CONDITIONS OF INTEREST INCLUDING NATURAL CIRCULATION THROUGH STEADY-STATE AND/OR TRANSIENT TESTS o SHOULD PROVIDE BOTH THE GLOBAL AND THE INTERNAL VARIABLES 30J}}