ML20150C308
| ML20150C308 | |
| Person / Time | |
|---|---|
| Issue date: | 05/03/1988 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2570, NUDOCS 8807120428 | |
| Download: ML20150C308 (40) | |
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} DATE ISSUED: 5/3/88 Advisory Comittee on Reactor Safeguards Thermal Hydraulic Phenomena Subcomittee Meeting Minutes April 19, 1983 Idaho Falls, ID PURPOSE: The purpose of the meeting was to review the draft models and correlations document for the RELAP-5/M00-2 thermal hydraulic code.
ATTENDEES:
ACRS NRC-RES C. Wylie, Acting Chainnan L. Shotkin I. Catton, Consultant N. Laubin M. Plesset, Consultant N. Zuber V. Schrock, Consultant P. Boehnert, Staff (DF0)
EG&G R. Duffey V. Ranson G. Wilson G. Johnsen R. Dimenna l J. Trapp l' R. Johnson R. Riemke R. Shumway R. Wagner MEETING HIGHLIGHTS, AGREEMENTS, AND REQUESTS
- 1. L. Shotkin (RES) provided opening remarks. He noted the current uses of RELAP-5 by NRC-RES for the plant analyzer, B&W MIST l
- program, the JAERI ROSA-IV effort, and the ICAP consortium. He said the code is also being used to address a number of regulatory issues. .
Dr. Shotkin noted that the RELAP-5 models and correlations (MC) report will provide final documentation for the code, with ,
ICICSATED ORIGINAL 8 880503 y -
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h71 2570 PDR
Thermal Hydraulic Phenomena Minutes April 19, 1988 justification of basic modelling, including the assessment process used to arrive at the final forms of models and correlations. The RELAP-5 code was originally designed to model SB LOCAs and tran-sients. The MC report focuses on the code pedigree. Modeling of basic T/H phenomena with different T/H codes (US and overseas) shows large variations in the codes' basic modeling capabilities.
He offered three possible reaso's for the differences: (1) certain edeling variations may have a , ijor effect on the code's ability to simulate integral test data. This may be particularly true for rate processes; (2) the code development process is not so dis-ciplined as to avoid the introduction of compensating errors; and (3) the T/H behavior of water and steam in a reactor geometry under accident conditions may be so complicated that it may never be possible to arrive at a unique set of basic two-fluid models and correlations.
Dr. Catton noted a leck of discussion on nunarical methods and on reflood phenomena in the MC document. Dr. Shotkin said that this is because the code was not designed to model large breaks. The MOD-3 version of REALP-5 will be fully able to model reflood. Dr.
Catton expressed surprise to hear that M00-2 is not a LB LOCA code.
Dr. Shotkin indicated that wr ile the code has been used to model LB LOCA, MODS 1 & 2 have not t .a assessed against LB LOCA test data.
! ,2 . R. Duffey (INEL) provided introductory remarks on the MC document.
( He distinguished between what the "Q/A" document is and is not j (Figures 1&2).
Dr. Catton again asked about use,of RELAP-5 for modelling LB LOCAs.
I Dr. Shotkin comented that in the past, the LB LOCA modeling effort was directed to the TRAC code. RES did not spend effort on assess-l ment of RELAF tor the LB LOCA. Mr. Laubin (RES-formally of NRR) indicated that ai far as he knows, NRR is not using RELAP-5 for LB LOCA modeling.
Thermal Hydraulic Phenomena Minutes April 19, 1988 '
Dr. Duffey said the day's presentations would focus on the diffi-cult and important modeling areas; for example, interphase relations (Figure 3). He said the code can analyze small breaks and system transients for PWR's and BWR's, provide insight on trends and timescales, and can be linkeu to core damage analysis.
It cannot analyze large breaks accurately, or provide detailed information on local phenomena.
In response to Dr. Plesset, G. Johnsen (INEL) said it will take "
30 man-months to develop LB LOCA redeling capability for MOD-3. It was noted that FRG is also supporting the MOD-3 LB LOCA effort ( w
$0.5M). Dr. Catton again emphasized that the MC document should contain discussion of the code's numerics. Dr. Shotkin said that there will be discussion of the numerics in both of the final QA reports (TRAC and RELAP-5).
t ,.
. 3. V. Ransom provided a historical perspective on development of the RELAP code. He indicated that the three main motivations for development were: (1) tt betheNRC"stalwart"code,(2)to providesimplicity,and(3)toincorporateuserconveniences.
The details of the RELAP-5 development chronology were reviewed (Figures 4-6). The MOD-2 version was completed in 1983. M00-2 we.::
then frozen in 1985 as part of the ICAP effort.
Dr. Ransom does not seen any need for major changes to the basic code structure, numerics, or constitutive relations. The code is l about as good as it can get. Dr. Plesset indicated strong agreement.
- 4. The development process for RELAP-5 was detailed by G. Johnsen. He discussed: (1) the procedures for new coding and changes, (2) the developmental assessment and testing, and (3) plans for the next
Thennal Hydraulic Phenomena Minutes April 19, 1988 codeversion(MOD-3). Mr. Johnsen said deficiencies are discovered via independent assessment and by use in regulatory applications.
The steps taken in the development process are detailed on Figures 7-10. Dr. Catton urp d INEL to publicize their code improvement needs in order to help secure funding from "outside" sources to correct the code deficiencies.
The details of the developmental assessment program for the code were shown. These include both separate effects and integral experiments. Dr. Catton urged INEL to document the set of standard problem exercises used to assess the code. He noted that some SB LOCAs may require use of the reflood model. The MC report should document the reflood process.
Development plans for the MOD-3 version were reviewed (Figure 11).
- The problems identified in the ICAP assessment effort will serve as the basis for improvements._ Release of MOD-3 is planned for July 1089. In response to Dr. Catton, Mr. Johnsen said the MOD-?
version will include "quasi-3D" capability for the core and down-
-- comer. Improvements in the constitutive relations, and in process and wall heat transfer models are planned.
- 5. R. Dimenna introduced the MC document. The objectives of the document are: (1) to provide detailed information on the quality of closure equations, (2) to describe how these closure relations are coded in the program, and assure that what is listed in the code manual is indeed what the code uses, and (3) to provide a technical rationale and justification for using these closure relations in the range of interest to NPP safety evaluations. Some information not included in the document (e.g. numerics) was omitted due to lack of time. INEL applied the principles used in
- a *O Thennal Hydraulic Phenomena Minutes April 19, 1988 the CSAU method (i.e., disciplined application of engineering judgment) to determine which phenomena are important across a wide range of reactor application conditions (Figure 12). These "key" phenomena took the bulk of the assessment effort. ,
Further Subcomittee discussion led to a conclusion that for some items in the document, (e.g., interfacial drag and area), INEL did not devote adequate discussion effort, as these are problem areas.
Mr. Dimenna acknowledged this deficiency. In response to Mr.
Schrock, Mr. Dimenna said approximately 50% of additional effort is needed to adequately conclude the MC report.
INEL said they would address the following topics for the remainder of the day: code field equations, flow regimes, and significant phenomenological models.
a.
J. Trapp (University of Colorado) reviewed the basic field equa-6.
tions, numerical guidelines, finite difference equations, and the needed constitutive models. Figures 13-17 provide highlights of the detailed discussions.
In response to Dr. Catton, Dr. Trapp noted that the time step smoothing method used in RELAP does not weigh the "old" (previous time step result) against the "new" (current time step result).
The INEL approach differs from the LANL approach in this area and in Catton's opinion, INEL is using the correct approach.
- 7. V. Ransom discussed the time smoothing scheme used in RELAP-5.
Although the codes are stable without smoothing, the penalty is in excessive run time. He compared the smoothing schemes used in TRAC and in RELAP-5. Dr. Catton urged INEL to fully document this scheme in the MC report in order to dispel ambiguities regarding the numeric time step process used, u
F-April 19, 1988 Thermal Hydraulic Phenomena Minutes
- 8. The flow regime maps used in RELAP-5 were discussed by R. Johnson.
Three maps are used: horizontal (including 15' from the horizon-tal), vertical, and high mixing (for pump flows). The flow regimes and transition criteria used for the horizontal and vertical maps are given in Figures 18-21.
Mr. Johnson noted that the code does not model churn turbulent flow. Messrs. Catton and Schrock noted that flow of this type has been seen in separate effects experiments modeling RCS loop flow in B&Wreactors(Ishiiet.al.). INEL acknowledged this point.
Shortcomings in the flow regime maps were noted, along with the shortcomings (limitations) of the Taitel-Dukler (T-D) theory upon which the maps are partially based. INEL believes additional data is needed for validation of the T-D transition criteria.
Mr. Schrock commented that he is unsatisfied with the INEL approach l ,
here. The transition criteria used are a serious shortcoming, and t
need to be revised. Dr. Duffey acknowledged this point.
[ 9. R. Shumway reviewed the modeling of wall heat transfer used in i RELAP-5. The nonequilibrium wall heat transfer model partitions the heat transfer between the liquid and vapor phases. The various wall heat transfer models used in MOD-2 were described (Figures 22-24). Results of predicted versus measured heat flux data show l
an underprediction error rate of ~ 25%. Significant weaknesses l remain in modeling of CHF and rewetting behavior.
l
- 10. R. Riemke discussed the interfacial heat and mass transfer models used in RELAP-5. He described the source terms used in the mass and energy equations, the mass transfer model (bulk exchange and wall) and the assessment of the above models.
l
4 Thermal Hydraulic Phenomena Minutes April 19, 1988 Concern was expressed by the Subconnittee consultants over the modeling approach used in the subcooled boiling model. The logic used is unnecessarily complex for the problem at hand.
The bulk exchange tenns used in the mass equations were detailed (Figures 25-26). The limits planced on the terms were also noted (Figure 27).
Assessment of the above models agair.st the: (1)Christensen subcooledboilingexperiment,(2)Bankoffcocurrentsteam/ water mixing experiment, and (3) Neptunus pressurizer experiment were shown. For the Bankoff experiment, Dr. Catton questioned the use of Dittus-Boelter as modified by INEL for the case in point. He concludes that the correlation is being used improperly. However calculations agree well with datal l
- 11. The momentum closure aspects of the code as applied to the interfa-I cial drag and entertainment modeling were reviewed by R. Dimenna.
Mr. Dimenna noted that the interphase drag model computes the
- phasic drag based on interfacial area, phasic velocity difference, and drag coefficient. Dr. Catton believes that the modeling l approach used here is incorrect for treatment of deaccelerating flow.
Results of separate effects assessment tests (Figure 30) for the l
interfacial drag model were shown. Dr. Zuber suggested that the l model be compared against a simple air / water experiment in order to i give a "warm feeling" that the model is viable. Test data are l readily available.
Results of the above test comparisons as well as comparisons with integral test data (LOFT) show that the interfacial drag package needs improvement (Figure 31). Improved interfacial drag models areunderconsideration(e.g.,Bestion,Chexal-Lellouche).
O Thermal Hydraulic Phenomena Minutes April 19, 1988 In response to Dr. Zuber, Mr. Dimenna indicated that the interfa-cial drag incdels currently in RELAP-5 represent a good develop-mental effort, but further improvements are needed.
- 12. R. Wagner discussed the key process models used in RELAP-5, including the one dimensional heat conduction model, reactor kinetics, decay heat models, pump model, abrupt area change model, valve model, critical flow model, and the overall central system control model.
In response to Mr. Schrock, INEL said the homologus pump curves now used in RELAP-5 are not recomended for use to model a full size plant. Each user is advised to obtain his own pump degradation Curve.
- 13. R. Duffey provided concluding remarks. He noted that the Subcom-l
' mittee made a number of useful, constructive criticisms. The i RELAP-5 code is in wide use and has a high level of acceptance.
Modest improvement will be made in MOD-3. Other, more basic
. suggestions for improvements made by the Subcomittee, will be forwarded to DOE for consideration.
I l Mr. Wylie thanked INEL for their excellent presentations. He l requested that the Consultants defer their coments on RELAP-5 to tomorrow when Messrs. Ward and Kerr will be present.
- 14. The meeting was recessed at 4:40 p.m.
- 15. Note: The Consultants made the following coments on the RELAP-5 MC report at the subcomittee meeting on April 20, 1988.
l l
Thermal Hydraulic Phenomena Minutes April 19, 1988 I. Catton - RELAP-5 has problems similar to TRAC. The "QA" docu-ment needs to be augmented. Both reports need discussion on the code's respective numerics. Discussion on reflood for RELAP-5 is needed. Also, the 1:apact of use of a constant Webber Number should be addressed (for TRAC as well). Both codes should receive some sort of peer review. The documents should be published as NOREG's ASAP. The issue of appling RELAP-5 to the LBLOCA should be cleared up - the code should not be limited to modeling of SB LOCA and transients.
M. Plesset - Prefers RELAP-5 to TRAC. RELAP-5 has kept the needs of the user in mind. He supports completion of M00-3. He recom-mends shelving some codes (like TRAC). .
V. Schrock - Concerned with the missing elements in the QA report,
, as is Dr. Catton. Believes the QA reports should be consistent
, from code-to-code. The flooding models need to be completely defined in the report, as does the stratification model. The practice of "modifying" correlations to be used in the code should
! not be done (both INEL and LANL are doing this). If it is done, the modification should be reported in the Literature in order to subject it to peer review, l
C. Wylie - INEL needs to specifically identify what' work is re-quired to convert RELAP-5 into a L8 LOCA code.
l NOTE: Additional meeting details can be obtained from a transcript l
I of this meeting available in the NRC Public Document Room, 1717 H Street, N.W., Washington, D.C., or can be purchased l
from Heritage Reporting Corporation, 1220 L Street, N.W.,
l Washington, D.C. 20555, (202) 628-4888.
l l
i
i l
WHAT IS A "Q/A" DOCUMENT AND PROCESS l
l IS:
o PEDIGREE / STATEMENT OF ORIGIN OF MODELS o IDENTIFIES POTENTIAL PROBLEM AREAS OBJECTIVELY AND CLEARLY o VERIFIED INDEPENDENTLY WHAT IS
._ ACTUALLY IN CODE o
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WHAT IS "Q/A" DOCUMENT AND PROCESS (CONT'D)
IS NOT:
o STATEMENT OF OVERALL CODE ADEQUACY o JUSTIFICATION FOR UNIQUE SET, OF 1
MODELS AND CORRELATION l 0 Q/A DOCUMENT IN "CONVENTIONAL" l
SENSE e ---
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FLOW REGIME ANNULAR INVERTED INVERTED HORIZONTAL VERTICALLY BUBBLY SLUG MIST ANNULh" SLUG DROPLET STRATIFIED STRATIFIED SHL -RN
]
SCL UnalM S-T M Theo M D-BM Brown M Brown M D-BM Const
+UnalM + Brown M +Unal M SHG L-RM D-BM Congt ! : Const I +L-RM +L-R L- @ l
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ft]h :
L-R - Lee-Ryley S-T - Seider-Tate D-B - Dittus-Boelter Theo - Theofanous "'
P-Z - Plesset-Zwick M - Modified TPhasic T sat E,sinceh ij ,7 large -
N Effective Interphase Relations: RELAP5/M002 12/87 x h D -
s
RELAPS CHRONOLOGY 1976-1978 - PILOT CODE EVOLUTION 5 EQUATIONS (1 ENERGY) TWO VELOCITY / DRIFT FLUX TEST NUMERICAL SCHEME .
TENTATIVE CONSTITUTIVE MODEL NUMBER DENSITY INTERPHASE DRAG RELAXATION MASS TRANSFER CHOKING MODEL 1978-1983 - SYSTEMS CODE DEVELOPMENT FUNCTIONAL MODULARITY
.' INPUT PROCESSlNG METHODS
~
READ, CHECK, INITIALIZE OUTPUT OPTIONS '
TIME STEP CONTROL ,
TRANSIENT SOLUTION MODULE ~
CONSTITUTIVE MODEL DEVELOPMENT PROCESS MODEL DEVELOPMENT S}L s
~
RELAP5 CHRONOLOGY (CONTINUED) 1979 - RELAP5/ MOD 0 FIRST SYSTEM MODELING CAPABILITY USED 1978 NRC BENCHMARK EXERCISE 1980 - RELAP5/ MOD 1 SMALL BREAK CONSTITUTIVE PACKAGE RELEASE AT FIRST INTERNATIONAL WORKSHOP 1982 - RELAP5/ MOD 1.5 LARGE BREAK MODELS
.. JET PUMP CONTROLS LIMITED RELEASE ,
1983 - RELAP5/ MOD 2 TWO ENERGY EQUATIONS INTERPHASE ENERGY TRANSFER / MASS TRANSFER IMPROVED INTERPHASE DRAG
'-9 NEW WALL HEAT TRANSFER -
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G RELAP5 CHRONOLOGY (CONCLUDED) ,
i 1984 - RELAP5/ MOD 2 DEVELOPMENTAL ASSESSMENT DOCUMENTATION RELEASE 1985 - RELAPS/ MOD 2 [FR0 ZEN VERSION]
NO MODEL IMPROVEMENTS PERMITTED DURING ICAP ASSESSMENT ERROR CORRECTIONS AND USER CONVENIENCE ADDITIONS ALLOWED y
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STEPS IN THE DEVELOPMENT PROCESS (1 0F 4)
- 1. DEFINITION OF DEFICIENCY OR NEED
- 2. LITERATURE REVIEW .
MATHEMATICAL MODELS RELEVANT DATA
- 3. SELECTION OF CANDIDATE APPROACH (ES) (PEER REVIEW) 1
~ -
l ADAPTATION "NEW" MODEL FORMULATION i
EVALUATION OF APPLICABILITY a ' ..
i 2
l STEPS IN THE DEVELOPMENT PROCESS i
l (2 0F 4)
- 4. DESIGN REPORT (LARGE, COMPLEX TASKS)
WHAT IS THE NEED?
WHAT OPTIONS ARE TO BE CONSIDERED?
l WHAT ACCEPTANCE TESTING WILL BE PERFORMED?
i
- 5. DEVELOPMENT OF PILOT CODING -
! 6. DEVELOPMENT AND CONDUCT OF TEST CASES i
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FOCUS: CONCEPTUAL PROBLEMS EXAMINE "REASONABLENESS" l -
EXAMINE LIMITING CONDITIONS AND TRANSITIONS l
REFINE CODING g
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11, RUN CASES FROM TEST CASE LIBRARY
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LIBRARY ENCOMPASSES CROSSECTION OF CAPABILITIES LOOK FOR EXPECTED AND UNEXPECTED CHANGES IN i RESULTS i -
VERIFY BASIC CODE FUNCTIONS (RESTART, PLOTTING, ETC.) ,
- 12. PREPARE DOCUMENTATION ,
COMPLETION REPORT (LARGE TASKS)
USERS MANUAL x .
DEVELOPMENT PLAN FOR RELAP5/ MOD 3 e IMPROVEMENTS BASED ON TWO-YEAR :
ICAP ASSESSMENT OF MOD 2 e COLLABORATIVE EFFORT INVOLVING INEL AND EXTERNAL ORGANIZATIONS:
SIEMENS (KWU) '
UK (CEGB)
SWITZERLAND SWEDEN i --
YANKEE ATOMIC NORTHEAST UTILITIES ,
o ESTIMATED RELEASE - JULY 1989 7
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l SOME PHENOMENA ARE IMPORTANT ACROSS A WIDE RANGE OF REACTOR :
! APPLICATION CONDITIONS. THESE PHENOMENA ARE CALCULATED i WITH THE FOLLOWING MODELS.
WALL HEAT TRANSFER o ENERGY CLOSURE -
INTERFACIAL HEAT -
- TRANSFER o MASS CLOSURE -
INTERFACIAL MASS TRANSFER I
o MOMENTUM CLOSURE -
INTERFACIAL DRAG ENTRAINMENT ,
, o PROCESS MODELS -
CRITICAL FLOW ABRUPT AREA CHANGE REACTOR KINETICS o CERTAIN COMPONENT MODELS
7HERMAL-HYDRAULIC SYSTEM TIME CONSTANTS o PROPAGATION SONIC: A X/A - 0.001 S KINEMATIC: A X/V ~ 0.05 S o INTERPHASE RATE l
MASS TRANSFER: 0.001 S l
INTERPHASE DRAG: 0.005 S o BOUNDARIES l - HEAT SOURCES, VALVES, CONTROLS, PUMPS l
1 i s,
- NUMERICAL DIFFERENCING GUIDELINES 0 MASS AND ENERGY TERMS TREATED CONSISTENTLY ;
o IMPLICIT ONLY WHEN NECESSARY ,
ACOUSTIC PROPAGATION STIFF ENERGY AND MOMENTUM COUPLING l
l 0 AVOID ITERATION
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LINEARIZE WHEN REQUIRED o
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1 RELAP5/ MOD 2 Difference Scheme i
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- Scalar node
- Mass and energy-
- P, 99, Pg, a, Ug, Uf control volume i
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i Vector node 1
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j i :- vg l l 1 '
l 4 4 -_ _
- 1 l l
- Vf l l
l 1 I t
X j + 1/2 i
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- Momentum
- j + 312 ,
l j - 1/2 ~
i j control volume j+1 ,
S3 2992 N,
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Ol __-___w _ - _ _ - _ _ _ _ _ . - _ . _ _ _ _ _ - _ _ _ _ _ _ . _ _ _ - _ . - _ _ -
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RELAP5/ MOD 2 Semi-Implicit Solution ..
i Strategy .
I-l I J + 112 I+I J - 112 n+1 - -
n+1- -
n+1 --
n 1-n vg
++3x
{ V xx x P [PJ j i j Vapor EOS [P];n _3+ 1 - g vg vg x x x j j Liquid EOS - - j - 112 x p - -j+1/2 xxxxx a xx x J Mixture Mass xx l U9 xx x j Phasic Mass Diff xx xxxxx l U i
x x- xxx r-j x x j j Vapor Energy + + + =
+ x x
- j Liquid Energy x xxxx x x J-112 Mom Sum x xx l x x xx x
) J -112 Mom Diff x xx x x l
J + 1/2 Mom Sum x xx x x J + 112 Mom Diff s_ __ _ _ _ _ _ _ __
y yy y First reduction yy l
1 y
y .
-l y 1
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y + + = y y + 1 +
y 1 y y y 1 y y
+ z z =
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5 Second reduction z + + z _ __ __
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MAJOR CONSTITUTIVE MODELS NEEDED o WALL DRAG: FWG, FWF l
! o INTERPHASE DRAG: FI i o WALL HEAT FLUX: Ows, QWF QIG, GIF l 0 INTERPHASE HEAT FLUX:
! o INTERPHASE MASS TRANSFER: FROM QIG AND QIF I
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N
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.i HORIZONTAL FLOW REGIMES o BUBBLY o SLUG o ANNULAR MIST o DISPERSED (DROPLET)*
o STRATIFIED
- NOT ADDRESSED BY TD A
HORIZONTAL TRANSITION CRITERIA o BUBBLY TO SLUG VOID FRACTION (TAITEL, B0RNEA, DUKLER 1980)
(VERTICAL)
MASS FLUX o SLUG TO ANNULAR MIST ,
V0ID FRACTION 0.75 TO 0.8 (TAITEL, DUKLER 1976, 0.5) o ANNULAR MIST ;$ DISPERSED (DROPLET) 50ID FRACTION = 1-10-7 (SM0OTHNESS) o STRATIFIED KELVIN-HELMHOLTZ (TAITEL, DUKLER 1976)
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VERTICAL FLOW REGIMES ,
o BUBBLY o SLUG o ANNULAR MIST o DISPERSED (DROPLET)*
Deyour o INVERTED REGIMES (POST-ERF)*
o STRATIFIED *
- NOT ADDRESSED BY TD b
~
VERTICAL TRANSITION CRITERIA o BUBBLY TO SLUG VOID FRACTION (TAITEL, BORNEA, DUKLER 1980)
SMALL TUBE (TAITEL, B0RNEA, DUKLER 1980)
MASS FLUX o SLUG TO ANNULAR MIST EFFECTIVELY VOID FRACTION (TAITEL, B0RNEA, DUKLER l 1980; WALLIS 1969) o ANNULAR MIST TO DISPERSED VOID FRACTION = 1-10-7 (SMOOTHNESS) o STRATIFIED TAYLOR BUBBLE VELOCITY o TRANSITION TO INVERTED FLOW REGIMES ANALOG 0US TO PRE-CHF (DE JARLAIS, ISHII 1985) s,
- s es 1 bl
l l
RELAP5/ MOD 2 Heat Transfer Models -
Heat Transfer Mode Model hwp = Max (Forced, Laminar,
- Single-Phase Liquid Convection- Natural) hwa = 0 u.
I hwp = Modified Chen NB
'l Subcooled Nucleate Boiling S hwo = 0 hw, = Modified Chen NB
-- Saturated Nucleate Boiling hwa- O Ocu, = Biasi (G > 200 kg/m 2-s) u- = Modified Zuber I Critical Heat Flux (G < 100 kg/m 2-s)
= Interpolation (100 < G < 200)
CCMAX012 i
D w .
.5 RELAP5/ MOD 2 Heat Transfer Models (continued)
Heat Transfer Mode Model q wr = Q cnir (FCHEN)
- ~
Transition Film Boiling fwa = q cc (1-FCHEN) q'ca -Max (FC,NC. Lam)
I c q wr = (Bromley-Pomerantz)(1-a) g + Sun Radiation O.,
' q wo - Max (FC.NC, Lam)
~
Film Boiling FC = (Dittus-Boetter)a NC = Modified Baylei Lam = (Sellars-Tribus-Klein)a CCMAX013 CN a
.. =
RELAP5/ MOD 2 Heat Transfer Models (concluded)
Heat Transfer Mode Model u.
hw, = 0 6; Single-Phase Vapor Convection
- hwa - Max (FC.NC. Lam) n_
hw, = Max (FC,NC. Lam)
Dittus-Boelter, Nusselt, Sellars-Tribus-Klein Condensation hwa - Max (FC, Lam)
FC = Carpenter-Colburn Lam - Chato for horizontal
= Nusselt for vertical CCMANOS4
(
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, BULK EXCHANGE TERMS (CONTINUED)
BUBBLY SLUG ANNULAR MIST HORIZONTAL VERTICAL BUBBLES TAYLOR BUBBLE DROPS LIOUID FILM STRATIFIED STRATIFIED 3.6 a bub 3.6 aqs Il-*TB) 4.5 3.6 a fd 4 IM A o 4 sin 0 c gf d b
d b
D *TB 2'o) d d
II-*f f) 5 II-*ff) (2 N 1r0 V-hjf,SCL Unal M Unal M Seider-Tate M Brown TheofanousM Dittus-Boelter 14.7 kg 0 6 hif,SHL Plesset-Zwick Plesset-Zwick 3x10 3x10 Dittus-Boelter 14.7 k d f(ATsf)
Lee- Ryl ef Lee- Ryley" d af(ATsf) 4 4 d hgg,SHG 10 10 Lee-Ryley N Lee-Ryley H Dittus-Boelter Dittus-Boelter 81.4 k g 10 f(ATsg) 4 4 4 4 4 4 hgg,SCG 10 f(ATg) ' '10 f(ATsq) 10 f(AT3q) 10 f(ATsg) 10 f(ATsg) 10 f(ATsg) 81.4 kg SCL - Subcooled Liquid SHL - Superheated Liquid SHG = Superheated Gas SCG = Subcooled Gas M - Modified S
f(AT39) - quadratic function of ATsg -T -T g (ATsf) - quadratic function of ATsf = Ts - Tg N
o.
BULK EXCHANGE TERMS (CONTINUED)
INVERTED ANNULAR INVERTED SLUG MIST BUBBLES VAPOR FIIM DROPS "TAYLOR" DROP a
gf d b
" (I' 8) II'*B) ! b'52 d d
II'"BI b *B N' O d d
hjf,SCL Unal N Dittus-Boelter Broun Brown" Brown" kg kg kg 6
hgf,SHL Plesset-Zgick 3x10 y f(ATs+) y f(ATsf ) y f(ATs >)
Lee-Ryley k
4 M hj g,SHG 10
[k Lee-Ryley Lee-RyleyN k k 4
Lee-Ryley N 4 hj g,SCG 10 f(ATg) [ [ 10 f(ATg)
SCL = Subcooled Liquid SHL = Superheated Liquid SHG = Superheated Gas SCG = Subcooled Gas M = Modified f(AT39) = quadratic function of AT3g = Ts -T g f(aTy ) = quadrahc yo ,cru. of ars j = T' - rp N
b ki
BULK EXCHANGE TERMS - LIMITING BEHAVIOR o MECHANISTIC MODELING RANGE IS 10-5 < c<g < 0.99999 l 0 IN THE 0 < c4G < 10-5 OR 0.99999 < c< g < 1.0 RANGE, A LARGE HTG OR HI F IS USED TO SATISFY MASS AND ENERGY CONSERVATION WHILE REQUIRING SATURATION CONDITIONS FOR APPEARANCE /DISAPPEARANLE o SINGLE PHASE - NONEXISTENT PHASE AT SATURATION VAPOR - H s = 0, HIF LARGE LIQUID IHIF = 0, nIG LARGE t
l i FLOW REGIME BASED INTERFACIAL
! AREA AND DRAG l BASIS FOR l REGIME INTERFACIAL AREA DRAG COEFFICIENT l NUKIYAMA-TANASAWA l PARTICLE DISTRIBUTION l WITH:
1 M
! ISHII AND.CHAWLA
! DISPERSED We = 10 (BUBBLES)
! (BUBBLY, MIST)
= 3 (DROPLETS)
M ll SLUG ISHII AND MISHIMA ISHII AND CHAWLA
~
TAYLOR BUBBLE 4
! l 9
lk
FLOW REGIME BASED INTERFACIAL 4 AREA AND DRAG (CONTINUED) i l BASIS FOR REGIME INTERFACIAL AREA DRAG COEFFICIENT
! GE0 METRIC IDEALIZATION ANNULAR MIST (LIQUID FILM, VAPOR BHARATHAN CORE) WITH ENTRAINMENT l;
I GE0 METRIC IDEALIZATION DARCY-WEISBACH HORIZONTAL WITH QUIESCENT FRICTION FACTOR l USING INTERFACE i STRATIFIED INTERFACE
' REYNOLDS NUMBER INVERTED REGIMES ROLES OF VAPOR AND LIQUID INTERCHANGED 7
h 1 s.
'4
THE RELAP5/ MOD 2 INTERFACIAL DRAG MODEL HAS BEEN ASSESSED WITH SEPARATE EFFECTS TESTS, INCLUDING:
o GE LEVEL SWELL - TEST 1004-3 1-FT DIA.
14 FT. HIGH SATURATED SYSTEM BLOWDOWN o DUKLER AIR-WATER FLOODING COUNTER-CURRENT AIR-WATER FLOW o CREARE'DOWNCOMER TEST HI ECC LIQUID DOWNCOMER PENETRATION N
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