assessment of relap5/mod2 against ecn-reflood experiments · the conclusions concerning the...
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NUREG/IA-O 112ECN-C-92-008
InternationalAgreement Report
Assessment of RELAP5/MOD2Against ECN-Reflood Experiments
Prepared byA. Woudstra, J. P. A. Van De Bogaard, P. M. Stoop
Netherlands Energy Research Foundation ECNService Unit General ServicesP. 0. Box 1, NL-1755 ZG PettenThe Netherlands
Office of Nuclear Regulatory ResearchU.S. Nuclear Regulatory CommissionWashington, DC 20555-0001
July 1993
Prepared as part ofThe Agreement on Research Participation and Technical Exchangeunder the International Thermal-Hydraulic Code Assessmentand Application Program (ICAP)
Published byU.S. Nuclear Regulatory Commission
NOTICE
This report was prepared under an international cooperativeagreement for the exchange of technical information. Neitherthe United States Government nor any agency thereof, or any oftheir employees, makes any warranty, expressed or implied, orassumes any legal liability or responsibility for any third party'suse, or the results of such use, of any information, apparatus pro-duct or process disclosed in this report, or represents that its useby such third party would not infringe privately owned rights.
Available from
Superintendent of DocumentsU.S. Government Printing Office
P.O. Box 37082Washington, D.C. 20013-7082
and
National Technical Information ServiceSpringfield, VA 22161
NUREG/IA-O112ECN-C-92-008
InternationalAgreement Report
Assessment of RBLAP5/MOD2Against ECN-Reflood Experiments
Prepared byA. Woudstra, J. P. A. Van De Bogaard, P. M. Stoop
Netherlands Energy Research Foundation ECNService Unit General ServicesP. 0. Box 1, NL,1755 ZG PettenThe Netherlands
Office of Nuclear Regulatory ResearchU.S. Nuclear Regulatory CommissionWashington, DC 20555-0001
July 1993
Prepared as part ofThe Agreenient~on Research Participation and Technical Exchangeunder the International Thermal-Hydraulic Code Assessmentand Application Program (ICAP)
Published byU.S. Nuclear Regulatory Commission
NOTICE
This report is based on work performed under the sponsorship of theNetherlands Ministry for Social Affairs and Employment. The information inthis report has been provided to the USNRC under the terms of an informationexchange agreement between the United States and The Netherlands (TechnicalExchange and Cooperation Agreement between the United States NuclearRegulatory Commission and the Netherlands Energy Research Foundation ECN).The Netherlands has consented to the publication of this report as a USNRCdocument in order that it may receive the widest possible circulation amongthe reactor safety community. Neither the United States Government nor TheNetherlands or any agency thereof, or any of their employees, makes anywarranty, expressed or implied, or assumes any legal liability ofresponsibility for any third party's use, of the results of such use, or anyinformation, apparatus, product or process disclosed in this report orrepresents that its use by such third party would not infringe privately ownedrights.
-2 -
ABSTRACT
As part of' the ICAP (International Code Assessment and Applications Pro-
gram) agreement between EON (Netherlands Energy Research Foundation) and
USNRC, ECN has performed a number of' assessment calculations with the com-
puter program RELAP5.
This report describes the results as obtained by EON from the assessment
of the thermohydraulic computer program RELAP5/MOD2/CY 36.05 versus a
series of reflood experiments in a bundle geometry. A total number of
seven selected experiments have been analyzed, from the reflood experi-
mental program as previously conducted by EON under contract of the Com-
mission of the European Communities (CEO). In this document, the results
of the analyses are presented and a comparison with the experimental data
is provided.
-3 -
EXECUTIVE SUMMARY
For both Pressurized and Boiling Water Reactors (PWR's and BWR's) the bot-
tom ref'looding process following a large break LOCA is one of' the phenome-
na of' great interest to be examined. To test the ability of RELAP5/MOD2 to
model such conditions a great number of experimental programs has been
conducted to study the reflood heat transfer process and quench front pro-
pagation for bottom flooding conditions. The assessment calculations as
reported in this document concern reflood experiments as conducted by the
Netherlands Energy Research Foundation (EON). The experimental facility
represents a 36-rod bundle segment of a standard 15 x 15 PWR fuel design
with an axially uniform power profile.
This report describes comparisons between RELAP5/MOD2 calculations and
measurements of wall temperatures at different levels, quench front
position, collapsed liquid level, mass inventory in the bundle and in-
tegrated boundary mass flows.
The prime conclusions are as follows:
- The RELAP5/MOD2 reflood heat transfer model is only valid for high
reflood rates.
- Liquid carry-over is strongly overpredicted.
- Refinement of' axial nodalization above the recommended value did not
improve the calculational results.
CONTENTS PAGE
ABSTRACT 2
EXECUTIVE SUMMARY 3
1. INTRODUCTION 7
2. FACILITY AND TEST DESCRIPTION 10
2.1. Geometrical layout 10
2.2. Instrumentation 10
2.3. Operational procedures 11
2.4. Test matrix 12
2.5. Selected experiments 12
3. CODE INPUT MODEL DESCRIPTION 21
3.1. Input model sensitivity analyses 21
3.2. Base case input model 22
3.3. Initial and operating conditions 22
4. RESULTS 27
4.1. Sensitivity analyses 27
4.2. RELAP5/MOD2 results vs. experimental data 27
4.3. Analysis of results 28
4.4. Suggestions for model improvements 29
4.5. User guidelines 29
5. RUN STATISTICS 69
6. CONCLUSIONS 70
REFERENCES 71
LIST OF TABLES 72
LIST OF FIGURES 73
APPENDIX A: RELAP5/MOD2 INPUT DECK 76
-7 -
1. INTRODUCTION
As part of the International Code Assessment and Applications Program
(ICAP) agreement between the Netherlands Energy Research Foundation (EON)
and the United States Nuclear Regulatory Commission (US-NRC), EON has con-
ducted a number of assessment calculations using the thermohydraulic
system code RELAP5/MOD2/CY 36.05. ref. [1). The assessment calculations as
reported in this document concern a selection of seven reflood experiments
as conducted by EON under contract of the Commission of the European Com-
munities (CEO). The results of this ECN-reflood experimental program have
been documented in ref. [2).
As described in NUREG-1271, ref. [5), quantification of code uncertainty
for Large Break Loss-of-Coolant Accidents (LB-LOCA), Small Break
Loss-of-Coolant Accidents (SB-LOCA) and operational transients requires a
large number of assessment calculations to be performed for a variety of
integral as well as separate effect experiments. For each of these three
classes of accidents, phenomenologically based code assessment matrices
have been composed for both the Pressurized and Boiling Water Reactors
environment (PWR's and BWR's). One of the phenomena to be examined con-
cerns the reflooding process following LB-LOCA in both PWR's and BWR's.
A number of separate effect experimental programs have been conducted to
study the reflood heat transfer process and quench front propagation for
bottom flooding conditions. Table 1.1 lists some of these experimental
programs including their main characteristics. As can be observed from
this table, the EON-reflood experimental facility represents a 36-rod
bundle segment of a standard 15 x 15 PWR fuel design. The ECN-reflood
experimental program differs from other reflood experimental programs
by the axially uniform power profile being used.
RELAP5/MOD2 reflood assessment results already available indicate that
discrepancies exist between code predictions and experimental results,
ref. [3). Liquid carry-over is grossly overpredicted and therewith under-
prediction of the collapsed liquid level occurs. Most of this RELAP5/MOD2
assessment work indicates the cause of overprediction of carry-over is an
overestimation of the interphase drag in rod bundle goers, particu-
-8 -
larly in the slug flow regime. As stated in ref. [3], most of the
RELAP5/MOD2 interphase drag model assessment during..the development stage
has been based mainly on tube and open vessel data, and only to a minor
extent on rod bundle data.
The ECN-reflood data base comprises a total of 48 experiments. Out of this
data base, a total of seven experiments have been selected for code
assessment, based on the different physical phenomena observed during the
experiments and the parameter variations used.
The structure and contents of this assessment document is as much as pos-
sible in conformity with the guidelines described in NTJREG-1271, ref. [5].
Chapter 2 presents a description of the ECN-reflood experimental facility,
the operating procedures and the test matrix. In chapter 3 the RELAP5/MOD2
input model is being described, as well as the initial and operating con-
ditions of the selected experiments. The results of' the RELAP5/MOD2 analy-
ses are presented in chapter 14 and compared against the experimental data.
Sensitivity analyses with respect to e.g. nodalization are also given in
chapter [4]. Information with respect to run statistics can be found in
chapter 5, followed by the conclusions in chapter 6. Finally, the
F{ELAP5/MOD2 input deck being used for one of the experiments is being
shown in Appendix A.
- 9-
Table 1.1. Comparison of some reflood experimental facilities.
No. f ros Heght Axial power RemarkNo. of ods Heiht (%) profile _______
Flecht 7 x 7 & 10 x 10 100 Cosine, 15 x 15Skewed
Flecht 21, 161, 163 10Cosine, 17 x~ 17seaset Skewed
Neptun 6 x 6 50 Cosine BWR geometry
TITF 8 x8 100 Flat PWR 17 x17rod geometry
ECN-reflood 6 x 6 100 Uniform PWR 15 x 15_________ _____________ _________________ 1 rod geometry
- 10 -
2. FACILITY AND TEST DESCRIPTION
An extensive description of the ECN 36-rod reflood experimental program
can be found in ref. [2). Here, only a brief description of the facility
and the experimental program will be given.
2.1. Geometrical layout
A schematic picture of the ECN 36-rod reflood test facility is shown in
Fig. 2.1. Apart from the test section, the facility consists of the fol-
lowing components:
- A pressurized water supply accumulator and injection line;
- Two carry-over tanks connected to the test section upper plenum;
- A blowdown tank for steam condensation.
Heat tracing of piping and vessels has been utilized to prevent steam con-
densation effects.
The test section itself comprises a 36-rod bundle, located inside a rec-
tangular low mass housing. The bundle consists of 32 electrically heated
rods and 4 unheated corner rods, which are used to bear instrumentation,
instrumentation leads and the grids. The indirectly heated rods (heated
length 3.00 m, outer diameter 10.7 mm) are divided into three concentric
rows. Axially a uniform power profile is applied, while radially the 4centre rods, the inner row and the outer row heater rods can be set at
different power levels to establish a radially non-uniform power or
initial wall temperature profile. The upper plenum of the test section
contains a mechanical steam water separator, see Fig. 2.2.
2.2. Instrumentation
The EON 36-rod reflood test facility has been instrumented using:
- thermocouples for temperature measurements;
- flowmeters for steam and water flow measurements;
- pressure transducers for absolute pressures, pressure differences
and water level measurements;
- resistors for heater current measurements.
- 11
The overall test facility instrumentation is shown in Fig. 2.1. Instru-
mentation directly coupled to the test section is shown in Figs. 2.3
and 2.4. As indicated, housing differential pressure cells are located
every 0.25 m to obtain void fraction measurements along the heated length
of the bundle. Channel thermocouples are mounted to measure the coolant
temperature radially and axially across the bundle. Apart from this, wall
thermocouples are positioned at 8 levels per rod at different azimuthal
positions, as shown in Fig. 2.4.
2.3. Operational procedures
In order to meet the initial conditions for each experiment, first the
accumulator is filled with water and heated to the desired coolant
temperature. Next, the test section, the carry-over vessels and steam/
water separator vessel are pressurized by nitrogen at the desired
pressure. The accumulator is pressurized with nitrogen up to a pressure
level which is necessary for the required flow rate control.
In case of radially uniform initial temperature profiles, the bundle was
initially low powered. For radially non-uniform high temperature profiles,
a radially non-uniform power profile was initially supplied to the bundle.
Once the initial pressure and temperature conditions are met, the desired
coolant flow is established. At the time when the coolant reached the bot-
tom side of the test section heated length the power is (stepwise) in-
creased to the desired level. This moment is determined by a fast tempera-
ture increase of the heater rod thermocouple at level 1, see Fig. 2.3.
This time, which could also be determined by a pressure increase of the
lowest differential pressure cell in the heated part of the test section
is defined as the "start of the experiment".
After all heater rods are quenched, as could be observed from the rod wall
thermocouple measurements, the heater power is switched off, and the ex-
periment is terminated.
- 12 -
2.4. Test matrix
The test matrix of' the experimental program was designed to provide an
experimental data base in order to determine the reflood phenomena as
a function of' the next parameters:
- flooding rate;
- system pressure;
- subcooling;
- initial cladding temperature and radial temperature distribution;
- rod power level and radial power distribution.
The range of test conditions and parameters studied during the ex-
perimental program is shown in Table 2.1. The complete test matrix com-
prises 48 experiments and is shown in Table 2.2.
2.5. Selected experiments
Out of the test matrix as shown in Table 2.2, 7 experiments have been se-
lected for purpose of code assessment. Those selected experiments are pre-
sented in Table 2.3. Selection of the experiments is based on both the
parameter variations being used for the various experiments, and the dif-
ferent physical phenomena being observed.
The data present in Tables 2.2 and 2.3 originates from ref. [2). However,
in order to perform tLhe code assessment work as accurate as possible, more
precise initial conditions have been obtained from the available data
tapes. These latter initial conditions have been summarized in Table 2.4.
- 13 -
Table 2.1. Range of' initial test conditions for the analyzed reflood
experiments
Initial heater rod wall temperature 200-C - 850-C
Power 1.7 - 5 W/cm2
Bundle outlet pressure
(upper plenum pressure) .2 - .6 MPa
Flooding rates:
Constant 1.4 - 8.0 cm/sec
Variable in steps 3.0 - 0.9 cm/sec
Coolant subcooling 20*C - 80*C
- 14
Table 2.2. Test matrix for the ECN-reflood program
Exp. Twall Power V i TinN.(P)initial, lev.4 (*C) (W/cm2) in/sc (o. (P) c.r. Ii.r. Io.r. c.r. Ii.r. Io.r. (csc) (C
321532163218322032213224322932303231410041024106411341144115411641174118411941204121412241244125412641274128412941304131413241334134413541364137413841394140414141424143414441454146414741494150
.6
.2
.6
.2
.2
.2
.4
200
200
600
400600
400600600
600
600
600
600600
800
800
800
800
800
200
200
600
400600
400600
60
600
600
600
600
600
800800800800800800800800
200
200
600
400600
400600
600
600600
600
600
800
8008oo800800800
3.33.43.31.74.03.44.13.43.43.33.33.63.83.83.83.83.73.63.63.63.61.93.603.605.24.83.63.6003.63.6553.603.603.603.603.63.63.63.6
3.63.73.61.82.23.72.93.73.73.63.63.63.63.02.23.02.23.63.63.63.61.72.23.62.23.65.05.02.12.23.63.62.22.1553.63.63.63.63.63.63.63.63.63.63.63.6
3.63.63.61.81.83.62.23.63.63.53.53.53.52.21.42.11.43.53.53.63.51.71.43.51.43.54.84.81.31.43.53.51.41.3553.63.63.63.63.63.63.63.63.63.63.63.6
1.5
.71.31.51.4
1.1-0.91.7-0.98.05.02.4
5.08.02.4
8
2.48
2.4
8
2.482.4
8
2.4
8
2.482.48
8040140100
10040100
40
100
40
100
100
100
40
60
120
c.r. - central rodsi.r. - inner ring rodso.r. - outer ring rods
- 15 -
Table 2.3. Selected experiments
Experi- Pres- Wall Power (W/cm') Inlet Inlet Sub
ment sure temp. velocity temp. cooling
(MPa) (K) c.r. i.r. o.r. (cm/s) (K) (K
3216 0.2 .473 3.4 3.7 3.6 1.5 313 80
3224 0.2 473 3.4 3.7 3.6 1.5 373 20
4100 0.2 873 3.3 3.6 3.5 8.0 373 20
4106 0.2 873 3.6 3.6 3.5 2.4 373 20
4120 0.2 873 3.6 3.6 3.6 8.0 313 80
4138 0.2 1073 3.6 3.6 3.6 2.4 373 20
14149 10.4 11073 13.6 3.6 13.6 1 2.4 1393 1 3
c.r. = central rods
i.r. = inner ring rods
o.r. = outer ring rods
Table 2.4. Initial and operating conditions
EXP P T t v Wall temperature (K) t Power Powerinn in level 2__ (MPa) (JKj () (M/S) 2_ 3 4F 5 6 7 8 (s) MW (W/cm)
3216- 0.2 313 0 00426.0
4. 0.1486 450 459 463 473 473 449 449 14 114805.3o .5
_____805.0 .014356 ___ _____ 587.5 115736.9 3.593224 0.2 373 0 0 0 475
5.0 0.014371 4716747 43 47 6 425: 113668.6 3.52___1192.5 .014193 __ __ 965.0 115347.2 3.57
41oo~ 0.2 373 0 0 0 8962.07.5 .0o 4 899 893 893 873 865 863 846 17.0 8962.0
7. 085920.5 114336.6 3.541 1_ 1000.0 .080549 __1_1 398.0 115819.2 3.59
4106 0.2 373 0 0 0 6505.07.4 o 6 6 6 6 7 7 5 6.0 6505.07.5 .023222 80 83 87 88 80 70 50 11.0 112308.7 3.48
1000.0_ .023222 ____781.0 114510.7 3.5541200 0.2 313 0 0 0 6558.0
5.9 0 849 851 859 857 860 859 841 13.0 6558.06.0 .081754 16.0 113832.5 3.53
____ 1000.0 o081754 1___ 1______ 131.5 115350.4 3.574138 0.2 373 0 0 0 18806.0
7.9 0 10 115 11 l8 12 12114.0 18806.08.0 .02349 10 115 11 118 12 121 1095 19.0 112584.2 3.49
1000.0 .02349 409.0 114032.4 3.53______1 1______ _ 799.0 114973.0 3.56
4149W 0.4 393 0 0 0 10390.05.9 0 102 18 14 11 15 11 03 10.0 10390.06.0 .023123 102 18 14 11 15 11 03 14.0 112502.3 3.49
200.0 .023267 574.0 114565.7 3.55380.0 .023275
1 _ _ 1___ 1_ _ 766.0 1 .023273 1_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
C'
- 17
suI'?LY VESSELTfST S!ECTION STEAM FLOW tTASURfNTNT SL6OUI)'J TAX%
2-
(I r p r
F - Io... L *Le..3. F - Preooefe. T - T-.i.rat-ro
- -- - -- Trace heative
Figure 2.1. ECN-Reflood test facility schematics.
- 18 -
.. i
Figure 2.2. Test section and steam/water separator.
- 19 -
chati. teopersturesPUISe-hesCad t.C.'Sin Cutler
3097
2375h
2553 !2
I 3 210 w
500
1 2500
f b-
5000
b653
500
cress soction Svcs 47.8 c22
subeha
hydras.iic diasecer 22.5 em rod di
len* 1bydrauiie disamter 10.6 sw
s15aer 20 .7 a
Figure 2.3. Reflood instrumentation in 36-rod bundle.
- 20 -
Q Dire ction of flow,
9
NORTH-7
9
Channel thermocouple incertain locations of levels e. ( an~d -t
cross section area
hydraulic diameter
47.8 cm2
12.5 mmsubchannel hydraulic diameter 13.6 mm
rod diameter 10.7 mm
Figure 2.14. Cross-section of the bundle with thermocouple positions.
- 21 -
3. CODE INPUT MODEL DESCRIPTION
The nodalization of the EON 36-rod reflood test facility is quite simple.
As indicated in Fig. 3.1 the electrically heated rod bundle is modelled as
a pipe which is connected to a heat slab representing the heater rods.
Mass flow, pressure and temperature of water entering the lower plenum of
the test section are controlled by the time dependent junction 115 and the
time dependent volume 110. Downstream of the test section, the steam water
separator has been modelled with the RELAP5 separator component. The sepa-
rator component is connected to the time dependent volumes 950 and 955.
3.1. Input model sensitivity analyses
Parameters for which a sensitivity analysis may be performed are the
length of the hydrodynamic nodes and the maximum number of fine mesh
intervals as applied by RELAP5/MOD2 to calculate the axial heat con-
duction in the rods when using the reflood model. User recommenda-
tions suggest a length of the hydrodynamic nodes between 0.15 and
0.61 m, and a maximum number of axial fine mesh intervals equal to 16
or 32. The maximum time step size should range between 0.01 and 0.05
seconds.
Four sensitivity analyses have been performed for experiment number 4100.
The parameter variations studied are listed in Table 3.1. while the cor-
responding nodalization schemes are presented in Fig. 3.1. The resulting
rod wall temperature time histories for levels 2 and 3 as identified in
Fig. 2.3. are shown in respectively Figs. 3.2 and 3.3. As can be observed
from these figures, run 1, 2, and 3 give approximately the same tempera-
ture behaviour. Run 4, in which volume lengths of 0.5 m have been used,
deviates significantly from the previous three runs, but nevertheless com-
es closest to the experimentally determined temperature-time histories.
However, for purpose of determination of code uncertainty the nodalization
of run 3 has been selected as the base case input model for code assess-
ment. The temperature time histories as obtained for this run only differ
to a minor extend from the ones resulting from run 1 and 2.
- 22 -
Furthermore, a hydrodynamic node length equal to 0.25 m as used in run 3seems to be the lower bound with respect to core modelling for an actual
nuclear power plant. RELAP5/MOD2 plant transient analyses using shorter
length of the core hydrodynamic nodes will end-up in unacceptably high
computer running times. The number of axial fine mesh intervals does not
appear to influence the calculated temperature time histories significant-
ly. Since a two times greater number of mesh intervals results in a small
increase in computer running time, as will be shown in chapter 5, the fi-
nest mesh intervals will be used in the base case input model.
3.2. Base case input model
Based on the considerations as outlined in the previous section, the base
case RELAP5/MOD2 input model nodalization is shown in Fig. 3.4. The hy-
draulic volumes have a length of 0.25 m and the number of axial fine mesh
intervals equal to 32. The maximum time step size is fixed at 0.01 s.
3.3. Initial and operating conditions
The initial and operating conditions are presented in Table 2.4. The data
have been fixed at these values by a careful examination of the available
data tapes. In Appendix A the input decks for experiment 3216 are given
for both the steady state calculation as well as the transient calculation
(restart of the steady state calculation). The input decks for the other
experiments can be obtained from Appendix A by replacing some data accor-
ding to Table 2.4.
- 23 -
Table 3.1. Sensitivity analyses performed for experiment no. 4100
Run no. Volume length Number of mesh Maximum time
(in) intervals () step size (s)
1 .125 16 0.01
2 .125 32 0.01
3 .25 32 0.01
1 4 1 .50 32 0.01
- 24 -
TS~vte 5 .
945 " t .126
HCATELA*Neli
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ridMsis .125
asoe? Us*
SteS as 1A1
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IThOMJUN lie
TWOVVMISt
PIPMIS2 M
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teAI IaWOODAUXATION SOi6
POO aan tm ww
a"TUO"I'L
0001
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TUGFVOL noa" 810" .28
a" is As
a" a .24
AS
if
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LEMOT" a" as is gas wLO Id
a" 07 is
8"" is
a" so AS
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I TWONW lie
5555 .5
Ste 5 .me1
4te 441 5 I
hKATSDLzENGT
&.5
F
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pipe5.5CM
M95 " Las
815 51 Al5
WMPiNW III
WO@AUZATiO" ScHmaRUN 9
Us WISH WrK*VALZ
WOCAURATION saHIMsRUN 4
as Was" SNM2VALS
Figure 3.1. Nodalization schemes for sensitivity study.
- 25 -
Figure 3.2. EXP 4I100; Wall temperatures at level 2.
TIME (SEC)
Figure 3.3. EXP 4100; Wall temperatures at level 3.
- 26 -
9501 1
ISEPARATOR410 ] .25
41002I 41003I MDP VOL
955
HEATEDLENGTH
3.0 M
310 15 .125
310 14 .25
310 13 .25
310 12 .25
310 11 .25
310 10 .25
310 09 .25
310 08 .25
310 07 ,.25
310 06 .25
310 05 .25
310 04 .25
3 10 03 .125310 02 .125310 01 1.125
XI TDPJN 115TMDPVOL INODALIZATION SCHEME
PIPE3.25 M
Figure 3.4I.
- 27 -
4. RESULTS
Comparisons between predictions with the code RELAP5/MQD2 and selected
test data from the ECN-reflood experiments [2) are described below.
4.1. Sensitivity analyses
The results of the sensitivity analyses as described in chapter 3.1
can be summarized as follows:
" The results of the coarse node model calculations (0.50 m) deviate
significantly from the results obtained with the fine node model
(0.125 and 0.25 in).
" The number of axial fine mesh intervals (16 or 321 does not influence
the calculated temperature time histories significantly as can be seen
in Fig. 3.2 and 3.3.
Based on these conclusions the nodalization as presented in Fig. 3.4. is
applied for the analyses.
4.2. RELAP5/MOD2 results vs experimental data
Code predictions are compared with the following measured quantities:
"Integrated boundary mass flows.
"Liquid mass inventory in the bundle.
"Collapsed liquid level.
"Quench front position.
"Wall temperatures at different levels.
Comparisons between code predictions and test data for the seven
selected reflood experiments are presented as follows:
Experiment 3216: figures 4.1 - 4.8.
Experiment 3224; figures 4.9 - 4.16.
Experiment 4100; figures 4.17 - 4.24.
Experiment 4106; figures 4.25 - 4.32.
Experiment 4120; figures 4.33 - 4.40.
Experiment 4138; figures 4.41 - 4.48.
Experiment 4149: figures 4.49 - 4.56.
- 28 -
4.3. Analysis of results
The calculations have been performed with the code RELAP5/MOD2 using the
available reflood model. As already mentioned in the previous section the
number of axial mesh intervals during reflood is set to 16 and the nodali-
zation presented in Fig. 3.4 is applied. The reflood model has to beactivated at the start of each calculation. The reflood heat transfer
package in the code RELAP5/MOD2, however, is only valid for flow patterns
occurring at high reflood velocities (inverted annular flow). As for low
reflood velocities a different flow pattern occurs (annular flow) a here-
with corresponding heat transfer package should have been applied. For
this reason agreement between calculated and experimental data can be ex-
pected for high reflood velocities. Only at these high reflood velocity
conditions a flow pattern with the quench front below the collapsed liquid
level will occur.
In Figs. 4.57 through 4.70 the RELAP5/MQD2 calculated and the experimental
results concerning quench front position and collapsed liquid level are
presented for the different selected cases.
Only for experiment 4120 the condition of a quench front below the col-
lapsed liquid level is met as can be seen in Figs. 4.65 and 4.66. For this
experiment the calculated values compare in general well with the ex-
perimental results as presented in Figs. 4.33 through 4.40.
Figs. 4.71 through 4.78 show the calculated and measured heat flux at
axial level 5, 6, 7, and 8 for experiment 4120. These figures show that
near the quench front the calculated heat flux is overpredicted and that
well above the quench front the heat flux is underpredicted. This explains
the overprediction of the wall temperatures below the quench front and the
underprediction of the wall temperatures above the quench front as pre-
sented in Figs. 4.39 and 4.40. The approach of the quench front causes a
faster wall temperature decrease in the calculation due to an overestima-
tion of the heat transfer and so the heat flux. Except for level 8 the
calculated wall temperatures for experiment 4100 show the same good agree-
ment as described above for experiment 4120 (Figs. 4.23 and 4.24). This
agrees well with the above stated simplification in the RELAP5/MOD2 re-
flood model concerning heat transfer and flow regime. Experiment 4120 as
well as experiment 4100 have a high reflood velocity leading to the in-
verted annular flow regime identical to the model in REL.AP5/MOD2.
- 29 -
The calculated wall temperatures for experiments 3216 and 3224 show a
large deviation from the experimental data (Figs. 4.7 and 4.8 and Figs.
4.15 and 4.16). These experiments have a low reflood velocity and for that
reason do not experience the inverted annular flow regime. For this reason
the heat transfer is widely underpredicted. Poor comparison results are
also obtained for experiment 4106, 4138, and 4149 where the quenching or~
the higher levels starts far too late or not at all. The calculated quen-
ching of level 2 and 3 in these experiments is reasonably predicted.
cFigs. 4.31 and 4.32, Figs. 4.47 and 4.48, and Figs. 4.55 and 4.56).
For almost all calculations the liquid carry-over is grosly overpredicted
and this results in an underprediction of the collapsed liquid level. The
overprediction of the carry-over of the water at the bundle outlet is that
an overprediction of the interphase drag in rod bundle geometries.
4.4. Suggestions for model improvements
As the reflood heat transfer package in the code RELAP5/MOD2 is only valid
for flow patterns occurring at high reflood velocities (inverted annular
flow) implementation of heat transfer correlations for other flow patterns
(annular flow) during reflood is recommended. Most of the RELAP5/MOD2
assessment work indicates an overprediction of the carry-over due to an
overprediction of the interfacial drag. This deficiency of the code is
also demonstrated in these analyses. For this reason the introduction of
a better correlation for the interfacial friction in the bubbly and slugflow regimes is suggested.
4.5. User guidelines
User recommendations in the RELAP5/MOD2 manual suggest a length of the
hydrodynamic nodes between 0.15 and 0.61 m, and a maximum number of axial
fine mesh intervals equal to 16 or 32. The recommended maximum time step
size should range between 0.01 and 0.05 seconds. In the base case
RELAP5/MOD2 input model for the presented reflood analyses the length of
the hydrodynamic nodes is 0.25 m with a maximum number of 32 axial fine
mesh intervals at the quench level. The maximum time step equals to 0.01
second.
- 30 -
C0.
C.,
0.0 100.0 200.0 300.0TIME (SEC)
Figure 4.1. EXP 3216; Mass injected.
C.,
0.0 100.0 200.0 300.0TIME (SEC)
Figure 4.2. EXP 3216; Mass steam out.
600.0
- 31 -
0.0 100.0 200.0 300.0 400.0 50 .0.0 600.0TIV.E (SEC)
Figure 4.3. EXP 3216; Total mass carry-over.
.. .. . . . . . . . .. . . . . .. . .
xC,......................
0XE N
o ______ _____ *..*....RELAP /MOD2 ____
0.0 100.0 200.0 300.0 1900.0 500.0 600.0TIM~E (SEC)
Figure 4.4. EXP 3216; Mass in the bundle.
- 32 -
0.0 100.0 200.0 300.0 A00.0 500.0 600.0TIME (SEC)
Figure 4{.5. EXP 3216; Collapsed liquid level.
z
-j
-cEXPERIMENTRELAP5/MOD2
O.0 100.0 200.0 300.0 A00.0 500.0 600.0-IM.E (SEC)
Figure 4.6. EXP 3216; Quench front position.
- 33 -
TIME (SEC)
Figure 14.7. EXP 3216; Wall temperatures at level 2, 3, 4j.
R
7-7
0 I- XEIEN EEG---o EXPERIMENT LEVEL 5
It0- EXPERIMENT LEVEL 67 iPc; -+ EXPERIMENT LEVEL 7 w
2 .RELAP5/MOD2 LEVEL 56- c!** RELAP5/MOD2 LEVEL 6
g **.RELAP!S/MOD2 LEVEL 8
M- 0,4 5Li
300.0TIME (SEC)
Figure ~4.8. EXP 3216; Wall temperatures at level 5, 6, 7, 8.
-- 34 -
-I
w
0.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0
TIVE (SEC)
Figure 4.*9 . EXP 3224; Mass injected.
800.0
Figure 4.10. EXP 3224; Mass steam out.
- 35 -
(n(n
0.0 100.0 200.0 300.0 400.0 500.0 600.0TIME (SEC)
Figure 4.11. EXP 3224; Total mass carry-over.
800.0
0*0
-707 _ _ __ _
EXPERIMENT
I.RELAP5/MOD20.0 100.0 200.0 300.0 400.0 500.0
I I__________ I I _____ _____ _____
o I I_________________
TIME (SEC)
Figure 4.12. EXP 3224; Mass in the bundle.
600.0 700.0 800.0
- 36 -
0.0 100.0 200.0 300.0 400.0 500.0 600.0TIM'E (SEC)
Figure 4.13. EXP 3224; Collapsed liquid level.
800.0
800.00.0 100.0 200.0 300.0 400.0 500.0 600.0TIME (SEC)
Figure 4.14. EXP 3224; Quench front position.
- 37 -
0.0 50.0 100.0 150.0 200.0TIME (SEC)
Figure 4.15. EXP 3224; Wall temperatures at level 2, 3, 4.
R
o --- EXPERIMENT LEVEL 5 0I.h-; EXPERIMENT LEVEL 6 ___
0CEXPERIMENT LEVEL 6 - ____ c-__
EXPERIMENT LEVEL 8
.RELAPS/MOD2 LEVEL 56_ _ I_v ..... RLP5MD vEE~j- RELAP5/MOD2 LEVEL 67 ___ _______
o u-.RELAPS/MOD2 LEVEL rýý
C; 11_1 __ LL.0C!0. 0. 000 £00 500 60. 0 0
1IME (SEC)
Figure 4.16. EXP 3224; Wall temperatures at level 5, 6, 7, 8.
- 38 -
0.0 50.0 100.0 150.0 200.0TIME (SEC)
Figure 4.17. EXP 4l100; Mass injected.
0.0 50.0 100.0 150.0 200.0TIM: (SEC)
Figure 4.18. EXP 4100; Mass steam out.
- 39 -
0.0 50.0 100.0 150.0 200.0 250.0TIME (SEC)
Figure 4.19. EXP 4100; Total mass carry-over.
0.0 50.0 100.0 150.0 200.0 250TIME (SEC)
Figure 4.20. EXP 4100; Mass in the bundle.
350.0
- 4o -
IA_ _ I_ _
C -
0.0 50.0 100.0 150.0 200.0 250.0 300.0 30.
TIME (SEC)
Figure 4.21. EXP 4100; Collapsed liquid level.
00
__________ _________ I..o~~- __ _ _ _ _____i.._ _ _ __ _ _ _ _
150.0 200.0TIME (SEC)
Figure 4.22. EXP 4100; Quench front position.
- 41 -
100.0TIM~E (SEC)
Figure 4.23. EXP 4100; Wall temperatures at level 2, 3. 4.
x. 'X *o . av U
UU.
-aEXPERIMENT LEVEL 6S-CEXPERIMENT LEVEL 6
h EXPERIMENT LEVEL 7....C RELAP5/MOD2 LEVEL 5 I
o, - RELAPS/MOD2 LEVEL 6gi .RELAP5/MOD2 LEVEL 7 ____________
a 5....RELA05/MOD2 LEVEL 8
0.0 50 .0 100 150.0 200.0 250.0 300.0 350.0
Figure 4.24. EXP 4100; Wall temperatures at level 5, 6, 7, 8.
- 42 -
400.0TIME (SEC)
Figure 4.25. EXP 4106; Mass injected.
C!
C -~EXPERIMENT _______
.....RELAP5/M002
70
0.0 200.0 400.0 600.0 800.0
TIME (SEC)
Figure 4.26. EXP 4106; Mass steam out.
- 4~3 -
ia
0.0 200.0 400.0 600.0TI WE (SEC)
Figure 4.27. EXP 4106; Total mass carry-over.
P
TIME (SEC)
Figure 4.28. EXP 4106; Mass in the bundle.
- 44 -
R
GEX PERIMENT..... RELAP5/MOD2
ji- IV, ~.Ay ~vA/l . ..... ................. ............ ...I....... ...........
In
0.0 200.0 400.0TIME (SEC)
600.0 800.0
Figure 4.29. EXP 4106; Collapsed liquid level.
400.0-iME (SEC)
800.0
Figure 4.30. EXP 4106; Quench front position.
- 45 -
Liw-
300.0TIME (SEC)
600.0
Figure 4.31. EXP 4106; Wall temperatures at level 2, 3, 4.
C!
3--c EXPERIMENT LEVEL 55-0EXPERIMENT LEVEL 66-eEXPERIMENT LEVEL 7
o -EXPERIMENT LEVEL 8x.x RELAP5/MOD2 LEVELS5.
*oRELAP5/M002 LEVEL 6 1v .... RELAP5/MOD2 LEVEL 7 1a .. EAP5/MOD2 LEVEL 81 ____i
oi
0.0 200.0 400.0TIME (SEC)
600.0 800.0
Figure 4.32. EXP 4106; Wall temperatures at level 5, 6, 7, 8.
- 46 -
0.0 50.0 100.0NIE, (SEC)
Figure 4.33. EXP 4120; Mass injected.
En,
Figure 4.34. Exp 4120; Mass steam out.
- 47 -
0.0 50.0 100.0 150.0TIME (SEC)
Figure 4.35. EXP 4120; Total mass carry-over.
-0.0 5C.0 110.071M4E (SEC)
Figure 4.36. Exp 4120; Mass in the bundle.
200.0
- 48 -
0.0 50.0 100.0 150.0TIME (SEC)
Figure 4.37. EXP 4120; Collapsed liquid level.
0.0 50.0 100.0 150.'TIME (SEC)
Figure 4.38. EXP 4120; Quench front position.
200.0
- 49 -
-CEXPERIMENT LEVEL 20CEXPERIMENT LEVEL 3h-.EXPERIMENT LEVEL 4
PELAP5/M0D2 LEVEL 2x ... PE' Ac5/MOD2 LEVEL 3
0 .. *ELAP5/MOD2 LEVEL 4
0.0 20.0 '0.0 60.0 80.0 100.0TIME (SEC)
Figure 4.39. EXP 4120; Wall temperatures at level 2, 3, 4.
04
SEXPERIMENT LEVEL 50 -o EXPERIMENT LEVEL 6
A- EXPERIMENT LEVEL 7I LAJc, EPERIMENT LEVEL 8
Figure 4.40. EXP 4120; Wall temperatures at level 5, 6, 7, 8.
- 50 -
C0.
In
0.0 200.0 400.0TIME (SEC)
Figure 4.41. EXP 4138; Mass injected.
Figure 4.42. EXP 4138; Mass steam out.
- 51 -
c;.
0. 6 . 0 .06,. 0 .TIME (SC
Fiure44.E 418 oa0
as ar-vr
0
0.0 200.0 400.0 600.0 800.0
T IME (SEC)
Figure 4.441 . EXP 4~138; Mass in the bundle.
- 52 -
0EN ________________
~ ill ____ _________ _________ _________
z0
Li-JLi L ! .............. :
-cEXPERIMENT................RELA0 5/MOD2
0.0 200.0 400.0TIME (SEC)
600.0 800.0
Figure 4.45. Exp 4138; Collapsed liquid level.
400.0TIME (SEC)
Figure ~4.46. Exp 4138; Quench front position.
- 53 -
0.0 100.0 200.0 300.0 40c.0 500.0 600.0 700.0IME (SEC)
Figure 4.47. EXP 4138; Wall temperatures at level 2, 3, 4.
C!
CL 3- EXPERIMENT LEVEL 5U 0-C EXPERIMENT LEVEL 6P - EXPERiMENT LEVEL 7;00- EXPERIMENT LEVEL B T ____
x .... RELAP5/MOD2 LEVEL 5* RELAP5/MOD2 LEVEL 6
.7 9)ELAP5/MOD2 LEVEL 7!a R~ELA-5/MO02 LEVEL 8
0.0 200.0 400.0 600.0 800.0TIME (SEC)
Figure 4.48. EXP 4138; Wall temperatures at level 5, 6, 7, 8.
- 54 -
0.0 100.0 200.0 300.0 400.0 500.0 600.0TIME (SEC)
Figure 4.49. Exp 4{149; Mass injected.
I
300.0
TIME (SEC)600.0
Figure 4.50. EXP 4149; Mass steam out.
- 55 -
0.0 100.0 200.0 300.0 AOO.0TIME (SEC)
Figure 41.51. EXP 41149; Total mass carry-over.
0.0 100.0 200.0 300.0 A60.0
TIME (SEC)
Figure 4.52. Exp 4149; Mass in the bundle.
- 56 -
0.0 160.0 260.0 300.0 400.0 500.0 600.0TIME (SEC)
Figure 4.53. Exp 4149; Collapsed liquid level.
0.0 100.0 200.0 300.0 400.0TIME (SEC)
Figure 4.54. EXP 4149; Quench front position.
- 57 -
200.0TIME (SEC)
Figure 4.55. Exp 414I9; Wall temperatures at level 2, 3, 4t.
D--- EXPERIMENT LEVEL 5IL -C EXPERIMENT LEVEL 6
h EXPERIMENT LEVEL 7a EXPERIMENT LEVEL 8
ix ... RELAP5/MOD2 LEVEL 5*... RELAP5/MOD2 LEVEL 6SRELAc'5/MOD2 LEVEL 7
*... ELAP5/MOD2 LEVEL 8
C?0
0. 0. 6. 3c!0.0 A00.0 500.0 6ý0.0TIME (SEC)
Figure 41.56. EXP 4149; Wall temperatures at level 5, 6, 7, 8
- 58 -
EXPERIMENTAL RESULTS
300.0TIh.A (EC600.0
Figure 4.57. EXP 3216; Experimental quench front and collapsed
liquid level.
RELAP5/MOD2 RESULTS
0
0
.... QUENCH FRONT-COLLAPSED IO.LEVEL
0.0 100.0 200.0 300.0 400.0 500.0 600TIME (SEC)
.0
Figure 41.58. EXP 3216; Calculated quench front and collapsed
liquid level.
- 59 -
EXPERIMENTAL RESULTS
z
0,
0.0 100.0 200.0 300.0 0.0 500.0 600.0 700.0 800.0-IVE (SEC)
Figure 4.59. EXP 3224; Experimental quench front and collapsedliquid level.
RELAP5/M0D2 RESULTS
02W
†...U ENCH FRONT-COLLAPSED LIO.LEVEL _______
00200400.0 600.0 800.0TIME (SEC)
Figure 4.60. EXP 3224; Calculated quench front and collapsed
liquid level.
- 60 -
EXPERIMENTAL RESULTS
0.0 50.0 100.0 150.0 200.0 250.C 30C.0 350.0'rI).E (SEC)
Figure 4.61. Exp 4100; Experimental quench front and collapsed
liquid level.
RELAP5/MOD2 RESULTS
.....QUENCH FRONTo -COLLAPSED UQ.LEVEL
z0
FA
.0 5 .0 100.0TIME (SEC)
250.0 300.0 350.0
Figure 4.62. EXP 4100; Calculated quench front and collapsed
liquid level.
- 61 -
EXPERIMENTAL RESULTS
400.0
Figure 4.63. EXP 4106; Experimental quench front and collapsed
liquid level.
RELAP5/M0D2 RESULTS
a
Figure 4.64. Exp 4106; Calculated quench front and collapsed
liquid level.
- 62 -
EXPERIMENTAL RESULTS
0.0 50.0 100.0 150.0 200.0TIVE (SEC)
Figure 4.65. EXP 4120; Experimental quench front and collapsed
liquid level.
RELAP5/MOD2 RESULTS
TIME (SEC)
Figure 4.66. ExP 4120; Calculated quench front and collapsed
liquid level.
- 63 -
EXPERIMENTAL RESULTS
0.
-1Li
0.0 203.0 '00.0 600.0 800.0-IV--- (SEC)
Figure 4.67. ExP 4138; Experimental quench front and collapsed
liquid level.
RELAP5/MO02 RESULTS
TIME (SEC)
Figure 4.68. ExP 4138; Calculated quench front and collapsedliquid level.
- 64 -
EZ(PERA.4ENTAL .RESUL-TS
Figure 4.69. Exp 4149; Experimental quench front and collapsed
liquid level.
RELAP5/MOD2 RESULTS
.....QUENCH FRONT ....
-COLLAPSED UIQ.LEVEL
z __ ___ ____ _ _ ___ ____ __ ____ ___ ___ ____ ___ ____ __ ___.___........._ ___
00 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Hi
ý,AnA7/ A AoQ AC? I_
two. 200.0 300.0TIME (SEC)
400.0 500.0 600.0
Figure 4.70. EXP 4149; Calculated quench front and collapsed
liquid level.
-. 65-
C'4X
0.0 30.0 60.0 90.0 120.0 150.0 180.0 210.0
Figure 4.71. EXP 4120;- Calculated heat flux at level 5.
TIMlE [SEC)
Figure 4.72. EXP 4120; Experimental heat flux at level 5.
- 66 -
C-
Cý
0.0 30.0 60.0 90.0 120.0TIME (SEC)
150.0 180.0 210.0
Figure 4.73. EXP 4120; Calculated heat flux at level 6.
ME.1 ISM~
Figure 4.74. EXP 4120; Experimental heat flux at level 6.
- 67 -
90.0 120.0TimE- (SEC)
Figure 4.75. EXP 4120; Calculated heat flux at level 7.
HEAT fLUX TO COCLA.'4T VS TIM. 0 2Ue 1l2,1322,23.33 LEVEL7
A -
+. 2..
S23 -
a4
n~I
C!
Figure 4.76. ExP 4120; Experimental heat flux at level 7.
- 68 -
.00** N
0
1*
I.-o I I.,iII-I
6 _ _ I_ _ _ _ _ _ _ _
.30.0 60.0 90.0 120.0TIME (SEC)1s0.0 480.0 210.0
Figure 4.77. EXP 4120; Calculated heat flux at level 8.
b
ý"-. 0
Figure 4.78. EXP 4120; Experimental heat flux at level 8.
- 69 -
5. RUN STATISTICS
The number of system seconds and the CPU time used for the four sensitivi-
ty analyses as presented in section 3.1. are given in Table 5.1. The num-
bers are based on 100 seconds process time. The analyses are performed on
the Cyber 855 mainframe computer of the Technical Computing Center (ENR)
at Petten, the Netherlands.
Table 5.1. Run statistics.
Length of the Axial fine CPU Process time
hydrodynamic nodes mesh intervals (s) (S)
Run 1; Exp. 100 .125 m 16 2429 100
Run 2; Exp. 4100 .125 m 32 2554 100
Run 3; Exp. 4100 . 25 m 32 909 100
Run 4; Exp. 4100 . 50 m 32 15931 100
- 70 -
6. CONCLUSIONS
The conclusions concerning the RELAP5/MOD2 analyses of some selected
reflood experiments can be summarized as follows:
- The reflood heat transfer model in RELAP5/MOD2 is only valid for high
reflood rates. This is the main reason that cladding temperatures are
well predicted for high reflood velocities (0.08 m/s) while a poor com-
parison is obtained for low reflood velocities (0.015 m/s).
Modification of the heat transfer model to include low reflood rates is
recommended.
- Entrainment of water in the bundle is strongly overpredicted for all
selected cases. For this reason modifications of the interfacial fric-
tion correlations for the bubbly and slug flow regime are recommended.
- Refinement of the axial nodalization (axial nodes smaller than recom-
mended in the RELAP5/MOD2 users guidelines) does not improve the calcu-
lational results.
- 71 -
REFERENCES
[1) Ransom, V.H. et al.:
RELAP5/MOD2 Code Manual,
NUREG/CR-4312. August 1985.
[2] Boer. T.C., de; Molen, S.B., van der,eta.
Heat Transfer to a Dispersed Two-Phase Flow and Detailed Quench
Front Velocity Research, CEO Report EUR 10074 EN, 1985.
[3] Code improvement plan for TRAC-PF1 and RELAP5, INEL, November
1987. DRAFT.
[4] Compendium of ECCS Research for Realistic LOCA Analysis.
NUREG-1230, April 1987. DRAFT.
[5] Guidelines and Procedures for the International Code Assessment
and Applications Program. NUREG-1271, April 1987.
- 72 -
LIST OF TABLES Page
1.1. Comparison of some reflood experimental facilities. 9
2.1. Range of initial test conditions for the analyzed reflood 13
experiments
2.2. Test matrix for the ECN-reflood program. 14
2.3. Selected experiments. 15
2.4. Initial and operating conditions. 16
3.1. Sensitivity analyses performed for experiment no. 4100. 23
5.1. Run statistics. 69
- 73 -
LIST OF FIGURES Page
2.1. ECN-reflood test facility schematics. 17
2.2. Test section and steam/water separator. 18
2.3. Reflood instrumentation in 36-rod bundle. 19
2.4. Cross-section of the bundle with thermocouple positions. 20
3.1. Nodalization schemes for sensitivity study. 24
3.2. EXP 4100; Wall temperatures at level 2. 25
3.3. EXP 4100; Wall temperatures at level 3. 25
3.4. Nodalization scheme. 26
4.1. EXP 3216; Mass injected. 30
4.2. EXP 3216; Mass steam out. 30
4.3. EXP 3216; Total mass carry-over. 31
4.4. EXP 3216; Mass in the bundle. 31
4.5. EXP 3216; Collapsed liquid level. 32
4.6. EXP 3216; Quench front position. 32
4.7. EXP 3216; Wall temperatures at level 2, 3, 4. 33
4.8. EXP 3216; Wall temperatures at level 5, 6, 7, 8. 334.9 EXP 3224; Mass injected. 34
4.10. EXP 3224; Mass steam out. 34
4.11. EXP 3224; Total mass carry-over. 35
4.12. EXP 3224; Mass in the bundle. 354.13. EXP 3224; Collapsed liquid level. 36
4.14. EXP 3224; Quench front position. 36
4.15. EXP 3224; Wall temperatures at level 2, 3, 4. 37
4.16. EXP 3224; Wall temperatures at level 5, 6, 7, 8. 37
4.17. EXP 4100; Mass injected. 38
4.18. EXP 4100; Mass steam out. 38
4.19. EXP 4100; Total mass carry-over. 39
4.20. EXP 4100; Total mass in the bundle. 39
4.21. EXP 4100; Collapsed liquid level. 40
4.22. WX 4100; Quench front position. 40
4.23. Exp 4100; Wall temperatures at level 2, 3, 4. 41
4.24. EXP 4100; Wall temperatures at level 5, 6, 7, 8. 41
4.25. EXP 4106; Mass injected. 42
- 74 -
Page
4.26. EXP 4106; Mass steam out. 42
4.27. ExP 4106; Total mass carry-over. 434.28. EXP 4106; Mass in the bundle. 43
4.29. EXP 4106; Collapsed liquid level. 444.30. EXP 4106; Quench front position. 444.31. EXP 4106; Wall temperatures at level 2, 3, 4. 454.32. Exp 4106; Wall temperatures at level 5, 6, 7, 8. 454.33. EXP 4120; Mass injected. 46
4.34. EXP 4120; Mass steam out. 464.35. EXP 4120; Total mass carry-over. 474.36. EXP 4120; Mass in the bundle. 474.37. EXP 4120; Collapsed liquid level. 48
4.38. EXP 4120; Quench front position. 48
4.39. EXP 4120; Wall temperatures at level 2, 3, 4. 49
4.40. EXP 4120; Wall temperatures at level 5, 6, 7, 8. 49
4.41. ExP 4138; Mass injected. 50
4.42. ExP 4138; Mass steam out. 50
4.43. EXP 4138; Total mass carry-over. 51
4.44. ExP 4138; Mass in the bundle. 51
4.45. EXP 4138; Quench liquid level. 52
4.46. EXP 4138; Quench front position. 52
4.47. EXP 4138; Wall temperatures at level 2, 3, 4. 53
4.48. EXP 4138; Wall temperatures at level 5, 6, 7, 8. 534.49. EXP 4149; Mass injected. 54
4.50. EXP 4149; Mass steam out. 54
4.51. EXP 4149; Total mass carry-over. 55
4.52. EXP 4149; Mass in the bundle. 55
4.53. EXP 4149; Collapsed liquid level. 56
4.54. EXP 4149; Quench front position. 56
4.55. ExP 4149; Wall temperatures at level 2, 3, 4. 574.56. EXP 4149; Wall temperatures at level 5, 6, 7, 8. 574.57 EXP 3216; Experimental quench front and collapsed liquid level. 58
4.58 EXP 3216; Calculated quench front and collapsed liquid level. 58
4.59 EXP 3224; Experimental quench front and collapsed liquid level. 59
4.60 EXP 3224; Calculated quench front and collapsed liquid level. 59
- 75 -
Page
4.61 EXP 4100; Experimental quench front and collapsed liquid level. 60
4.62 EXP 4100; Calculated quench front and collapsed liquid level. 60
4.63 EXP 4106; Experimental quench front and collapsed liquid level. 61
4.64 ExP 4106; Calculated quench front and collapsed liquid level. 61
4.65 EXP 4120; Experimental quench front and collapsed liquid level. 62
4.66 EXP 4120; Calculated quench front and collapsed liquid level. 62
4.67 EXP 4138; Experimental quench front and collapsed liquid level. 63
4.68 EXP 4138; Calculated quench front and collapsed liquid level. 63
4.69 EXP 4149; Experimental quench front and collapsed liquid level. 64
4.70 EXP 4149; Calculated quench front and collapsed liquid level. 64
4.71 EXP 4120; Calculated heat flux at level 5. 65
4.72 EXP 4120; Experimental heat flux at level 5. 65
4.73 EX? 4120; Calculated heat flux at level 6. 66
4.74 EXP 4120; Experimental heat flux at level 6. 66
4.75 EXP 4120; Calculated heat flux at level 7. 67
4.76 EXP 4120; Experimental heat flux at level 7. 67
4.77 EXP 4120; Calculated heat flux at level 8. 68
4.78 EXP 4120; Experimental heat flux at level 8. 68
Win4ll. rap
- 76 -
Appendix A. RELAP5/MOD2 input deck.
=REFLOOD Exp 3216
100101
NEWRUN
STDY-ST
*TIME STEPS
201END0.5
MIN.5E-4
MAX. 01
31013101
CTRL~ MINED MAJED REST202 25 1000 1250
*****20800001 TREWET*****20800002 ZTRWT
*MINOR EDITS
301
303304305306307308309
*TRIPS
pZTRWI
HTTEMPHTTEMPHTTEMPHTTEMPHTTEMPHTTEMPHTTEMP
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- 77 -
03100000031000010310010103100201031002020310020303100204031002050310020603100207031002080310020903100210031002110310021203100213031002140310030103100302031003030310060103100801031009010310090203100903031009040310090503100906031009070310090803100909031009100310091103100912031009130310091403101001031011010310120103101202031012030310120403101205031012060310120703101208031012090310130003101301
HEATER15.004785
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90.4 . OE-5.0.0.0717.0.0717.0.0717
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- 78 -
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01150000011501010115020001150201011502020115020301150204
UPPLEN3. 0047854. OE-534100100000.04100000000.03100100000.0
OUTLET1000000.4. OE-530.
OUTLET1000000.4. OE-530.
INLET11000000000.04.95.0805.0
SEPARATR0.25.0118200000.9500000000.09550000000.04100000000.0
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- 79 -
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*TABLES
20770
20277700
TBL/FCTN20 .03.22E+6
TBL/FCTN16.73.2 66E+6
TBL/FCTN
1 1 *BORONNITR.
1 1 *HETER
1 1273.15 12.9805
255.37 3561611.533.15 4233615.699.82 4502416.
2000.00 5376019.
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422.04 3964814.588.71 4334415.810.93 4636816.
2000.0 25.1060
477.59644.26
1366.48
4099214.4435081.5376019.
POWER 510 1 . 1 .0.0 426. 14.5 426. 17.5 114805.3 587.5 115736.9
- 81 -
* CONTROL VARIABLES
205001002050010120500102205001032050010420500105205001062050010720500108205001092050011020500111205001122050011320500200205002012050020220500203205003002050030120500302205003032050040020500401205004022050040320500500205005012050060020500601205007002050070120500800205008012050080220500803
COLLVL0.0
STEAM-OUTVELGJRHOGJVO IDGJWATER-OUTVELFJRHOFJVOIDFJWATER-INVELFJRHOFJVOIDFJINJECTEDCNTRLVARS TEAM- OUTCNTRLVARWATER-OUTCNTRLVARMAS S0.0
sum0.1250.2500.2500.2500.2500.2500.2500.2500.2500.2500.2500.2500.125MULT410030000410030000410030000MULT410030000410030000410030000MULT115000000115000000115000000INTEGRAL4INTEGRAL2INTEGRAL
1.0VOIDFVOIDFVOIDFVa IDFVO IDFVOIDFVOIDFVOIDFVOIDFVOIDFVO IDFVO IDFVO IDF.004785
0.0 13100300003100400003100500003100600003100700003100800003100900003101000003101100003101200003101300003101400003101500000.0 1
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1.0 10.0CNTRLVARCNTRLVARCNTRLVAR
-1.0-1.0
S567
- 82 -
R EFLOOD EXP 3216
100101103
RE STARTRUN54
TRANSNT
*TIME STEPS
201END MIN550.0 .5E-4
MAX.01
CTRL MINED MAJED REST202 25 1000 1250
2080000120800002
TREWETZTRWT
31013101
*MINOR EDITS
301302303304305306307308
*TRIPS
501510520530600
20010
20501000
PZTRWTHTTEMPHTTEMPHTTEMPHTTEMPHTTEMPHTTEMP
3100100003101310100505310100705310100905310101105310101305310101405
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0000
1000. N *END0.0 Ls *POWER0.0 Ls *FILL FLOW.0 L *REFLOOD
Q-FRONT-0.250
sum1.0
1.0ZTRWT
0.0 13101
NRC F RM 335 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER12.ag,) (A~sslomd by NRC. Add Vol.. Ilwoo.. Rev..NRcM 1102. q ad Addendum Numbers. if sav.)3201. 320? BIBLIOGRAPHIC DATA SHEET NUREG/IA-0112
(See iflstfuctiofl on the reere ECN-C-92-0082. TITLE AND SUBTITLE
Assessment of RELAP5/M4OD2 Against ECN-Reflood Experiments 3. DATE REPORT PUBLISHEDMONTH YEAR
July 19934. FIN OR GRANT NUMBER
L2245S. AUTHOR(IS) 6. TYPE OF REPORT
A. Woudstra, J. P. A. Van De Bogaard, P. M. Stoop Technical
7. PERIOD COVERED (inclusive Direst
8. PERFORMING ORGANIZATION - NAME AND ADDRESS (II NRC.provide Division. 0/lice or Region. U.S. Nuclear Regulatory Commission, and mailling #ddrvus.it conrracror, providenew edmesadwling addrvess.J
Netherlands Energy Research Foundation ECNService Unit General ServicesP. 0. Box 1, NL,-1755 ZG PettenThe Netherlands
9. SPONSORING ORGANIZATION - NAME AND ADDR ESS PIlNRC. type *Tn as above"; if cantractor. Provide NRC Division. Jllice or Region. U.S. Nuclear Regulatory Commission.and mailing edoressj
Office of Nuclear Regulatory ResearchU. S. Nuclear Regulatory CommissionWashington, DC 20555 -000 1
10. SUPPLEMENTARY NOTES
11. ABSTRACT 1200 words or lear)
As part of the ICAP (International Code Assessment and Applications Program) agreement between ECN(Netherlands Energy Research Foundation) and USNRC, ECN has performed a number of assessment calculationswith the computer program RELAP5.
This report describes the results as obtained by ECN from the assessment of the thermohydraulic computer programRE-LAPS/MOD2/CY 36.05 versus a series of reflood experiments in a bundle geometry. A total number of sevenselected experiments have been analyzed, from the reflood experimental program as previously conducted by ECNunder contract of the Commission of the European Communities (CEC). In this document, the results of theanalyses are presented and a comparison with the experimental data is provided.
12. KEY WORDSIDESCR PTOR S (List words or phroses that will assist tesarchers In locating the reporr.i1 13. AVAI LABI LITY STATEMENT
RELAP5/MOD2, ICAP, thermohydraulic Unlimited14. SECURITY CLASSIFICATION
iThitPage!
Unclassified(mis Radon!
Unclassified15. NUMBER OF PAGES
16. PRICE
NRIC FORM 335 (2491
Federal Recycling Program
NUREG/IA-0112 ASSESSMENT OF RELAPS/MOD2 AGAINST ECN-REFLOOD EXPERIMENTS
UNITED STATESNUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555-0001
JULY 1993
SPECIAL FOURTH-CLASS RATEPOSTAGE AND FEES PAID
USNRCPERMIT NO. G-67
OFFICIAL BUSINESSPENALTY FOR PRIVATE USE, $300