NUREG/IA-0168

* International

Agreement Report

Assessment of RELAP5/MOD3.2

for Thermohydraulic Processes in

Heated Rod Bundles with

Tight Lattice at CKTI Test Facility

Prepared by

A. S. Devkin

Nuclear Safety Institute

Russian Research Center

"Kurchatov Institute"

123182, Moscow

Russia

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

October 1999

Prepared as part of

The Agreement on Research Participation and Technical Exchange

under the International Code Application and Maintenance Program (CAMP)

Published by

U.S. Nuclear Regulatory Commission
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NUREG/IA-0168

International

Agreement Report

Assessment of RELAP5/MOD3.2

for Thermohydraulic Processes in

Heated Rod Bundles with

Tight Lattice at CKTI Test Facility

Prepared by

AL S. Devkin

Nudcear Safety Institute

Russian Research Center

"Kurchatov Institute"

123182, Moscow

Russia

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555-0001

October 1999

Prepared as part of

The Agreement an Research Participation and Technical Exchange under the International Code Application and Maintenance Program (CAMP)

Published by

U.S. Nuclear Regulatory Commission

ABSTRACT

The assessment of RELAP5/MOD3.2 for two-phase hydrodynamics and heat

transfer processes in the rod bundle model with tight lattice are presented. This

experiments have been carried out at the bundle with non-standard geometrical

characteristics - close packed assembly and small hydraulic diameters. The

investigations have been carried out at the following range of parameters: pressures

P = 0.23-2.0 MPa, inlet water flowrate from zero up to G=17-18.3 kg/c, heat fluxes

q - up to 0.96 kW/m2 and void fractions a = 0.03 -0.89.

RELAP5/MOD3.2 assessment for processes at steady state conditions at small

or zero flowrates at the inlet of the tube bundle showed that for such processes code

gives rather good results. The comparison of computed and experimental results for

process of boil-off and reflooding shows that there is a good coordination between

computed and experimental values between temperatures of pipe bundle walls for

upper part of the bundle. For lower part of the bundle there are some discrepancies

between computed and experimental values of temperature, the later being some

lower than experimental ones. The calculated values of shroud temperature were

rather less than experimental ones.

iii

CONTENTS

Abstract iii

Executive Summary ix

L Introduction 1

2. Experimental Facility Description 1

3. Results of The Experiments 4

Table 2. Experimental Data for Low Flowrates 4

Table 3. Experimental Data for Closed Inlet 6

4. Nodalization Scheme 6

S. Results of Calculations for Steady State Conditions 7

6. Results of Calculations for Boioff Test and Sensitivity

Analysis 16

7. Run Statistics 27

8. Conclusions 28

Appendix: RELAPS Input Deck 29

V
LIST OF FIGURES

Fig. 1 Scheme of CKTI Test Facility 1

Fig. 2 Test Section 2

Fig. 3 Cross Section of Rod Bundle 3

Fig. 4 Nodalization Scheme of Test Facility 7

Fig. 5 Dependence of Void Fraction From Superficial Velocity

for Two Levels for Low and Zero Flowrates and

Low Pressures 10

Fig. 6 Results of Calculations and Experimental Ones for

Low Flowrates and Pressure 2 MPA 10

Fig. 7 Dependence of Void Fraction From Equilibrium

Quality at P=0.23 MPA 11

Fig. 8 Dependence of Void Fraction From Equilibrium

Quality at P-2.0 MPA 11

Fig. 9 Dependence of Void Fraction From Superficial

Velocity for Closed Inlet 12

Fig. 10 Dependence of Void Fraction From Superficial

Velocity at P=0.23 -0.54 MPA 13

Fig. 11 Dependence of Void Fraction From Superficial

Velocity at P=2.0 MPA for "Bundle" Option 13

Fig. 12 Dependence of Void Fraction From Superficial

Velocity at P=-2.0 MPA for "Bundle" Option 14

Fig. 13 Collapsed Level Behaviour 16

Fig. 14 Physical Level Behaviour 17

Fig. 15 Rods Temperature Distribution Along the Height

Before the Reflooding Stage 17

Fig. 16 Rod Temperature Behavior at Z-=0.28M 18

Fig. 17 Rod Temperature Behaviour at Z-0.66M 19

vi
LIST OF FIGURES (Continued)

Fig. 18 Rod Temperature Behaviour at Z=0.75M 19

Fig. 19 Rod Temperature Behaviour at Z=0.9M 20

Fig. 20, Rod Temperature Behaviour at Z=0.95M 20

Fig. 21 Rod Temperature Behaviour at Z=0.95M with Taking

into Account Rod Electrical Resistance Dependency

From Temperature 21

Fig. 22 Collapsed Level Behaviour With Different Upper Volume 22

Fig. 23 Rod Temperature Behaviour at Z=0.95 With Different

Power Distribution Between Rods and Shroud 22

Fig. 24 Rod Temperature Behaviour at Z=0.95 With Taking

into Account Presence of Insulators 23

Fig. 25 Shroud Temperature Behaviour at Z=0.35M 24

Fig. 26 Shroud Temperature Behaviour at Z-0.88M 24

Fig. 27 Shroud Temperature Behaviour at Z=0.88M With

Different Heat Losses 25

Fig. 28 Rod Temperature Behaviour at Z=0.95 With

Different Heat Losses a 26

Fig. 29 Shroud Temperature Behaviour at Z=0.35M With

Different Heat Losses 26

Fig. 30 Time Step Behaviour During Boiloff and Reflood Test 27

Fig. 31 CPU Time During the Test Calculation 28

vii
LIST OF TABLES

Table 1. Characteristics of Test Section 3

Table 2. Experimental Data for Low Flowrates 4

Table 3. Experimental Data for Closed Inlet 6

Table 4. Results of Calculations and Experimental Ones for

Low Flowrates 9

Table 5. Results of Calculations and Experimental Ones for

Closed Inlet 12

Table 6. Results of Calculations and Experimental Ones for

Low Flowrates ("Bundle" Option) 15

Table 7. Results of Calculations and Experimental Ones for

Closed Inlet ("Bundle" Option) 15

vili
EXECUTIVE SUMMARY

This report presents the results of RELAP5/MOD3.2 assessment in the

prediction of two-phase hydrodynamics and heat transfer in rod bundle model with

tight lattice. The experiments have been carried out at the CKTI (St' Petersburg) test

facility. The peculiarities of these researches were the non-standard geometrical

characteristics of the 55-rod bundle - close packed assembly and small hydraulic

diameters, and also the parameters - small flowrates (down to zero) and low pressure

(from 0.23 up to 2.0 MPa).

The assessment of RELAP5/MOD3.2 code was done for two cases: for steady

state conditions at small or zero flowrates at the inlet of the rod bundle and for boiloff and reflooding processes. The comparison of calculated results with experimental

ones shows that there was a good coordination between computed and experimental

values of void fractions and bundle wall temperatures for almost all the tests.

ix

1. INTRODUCTION

RELAP5/MOD3.2 assessments for low velocity two-phase flow hydrodynamics

and heat transfer processes in the rod bundle model are not numerous. All the more such

assessments are interesting for non-standard geometry as for rod bundles with tight

lattice. Such experiments have been carried out at CKTI test facility (St' Petersburg). The

peculiarities of these researches were the non-standard geometrical characteristics of the

bundle - close packed assembly and small hydraulic diameters, and also the parameters -

small flowrates (down to zero) and low pressure (from 0.23 up to 2.0 MPa).

The assessment of RELAP5/MOD3.2 code was done for two cases: for steady

state conditions at small or zero flowrates at the inlet of the rod bundle and for boil-off

and reflooding processes.

2. EXPERIMENTAL FACILITY DESCRIPTION

CKTI test facility (Fig. 1) consists of test section, system of preparing of flow with

needed parameters and measurement system.

Pnrheeter

Fig. 1 Scheme of CKTI test facility

I
Fill wi

Fig. 2 Test section

Test section is a 55-pipes bundle with 6x1 mm diameter stainless steal tubes with

heated length 1006mm (Fig. 2). 6 comer pipes were made from insulator (Fig. 3). Pipe

bundle was placed into the shroud 61 x 1 mm. Pipe bundle and shroud were heated with

alternating current. There were five grids along the bundle. First grid was near the bottom

and the distance between them was 200 mm. The pitch of the bundle equals to 7.35 mm.

The comer rods were made from insulator 5mm diameter and they were unheated (Fig.

3). All the elements of the model excluding the comer rods and copper current supply

were made of stainless steel 12X18H1OT. The bottom part of the model had the flow inlet

orifice 10mm diameter and the upper one had two ones: axial orifice 18mm diameter for

flow outlet and side one 10amm diameter for flow inlet for tests without bottom inlet flow.

Flow control for different tests series was made with using valves 1 - 4 (Fig. 1).

2
Fig. 3 Cross section of rod bundle

Geometrical and hydraulic characteristics of tube bundle are presented in Table 1.

Table 1. Characteristics of test section

Element Hydraulic Length, mm Area, Flow losses

diameter, mm Mmm2

Bundle inlet 10 170 78.5 365

Tube bundle 3.77 .1006 1249 13.04

Bundle outlet 20 21 2515 0.155

Flow area and flow losses of each row of grid equal to 1072 mm2 and 0.49

accordingly.

Upper plenum volume between bundle outlet and outlet orifice equals to 0.6x 0-3

in3.

There were the preheater before the bundle inlet - electrical heated tube 22x3mm

diameter with length 3m inclined at 70 to horizon.

During the experiment the following parameters were measured:

" Pressure in the top of the model,

" Pressure differences along the channel at locations shown at Fig. 1,

" Flow temperatures at the bundle inlet and outlet and before the preheater,

" Inner heated tubes walls temperatures (54 thermocouples), the axial distance between

the thermocouples were 20-30mm,

3
" Mass flowrate at the bundle inlet,

" Electrical power which is a sum of the bundle and shroud power and it was divided

between them as 0.8 : 0.2.

Void fraction was determined as an average value between two pressure drop

measurement locations. The accuracy of this method at low flowrates is rather small and

equals to Aa = (2 - 6)x 10-2.

3. RESULTS OF THE EXPERIMENTS

First series of experiments was devoted to investigation of void fraction at low

upward flowrates. The parameters of the investigations were the following: pressures P =

0.23-2.0 MPa, inlet water flowrate G=17-18.3 kg/c, heat fluxes q-up to 0.96 kW/m2 and

void fractions a = 0.03 -0.89.

The results of this experiments are shown in Table 2, in which T is water

temperature at the preheater inlet, G - water flowrate, Q - preheater or bundle power, a -

void fraction and Jg =aVg- superficial vapor velocity.

Table 2. Experimental data for low flowrates

Test N T inlet, G, P, Q preheater, Q al/a 2 001/04$)2

C kg/s MPa kW bindle, experiment experiment

kW

6 95 17.9 0.23 7.55 1.04 0.62/0.52 1.4/1.33

7 95 18 0.23 7.55 2.34 0.66/0.55 1.7/1.6

8 95 18.4 0.23 7.55 3.9 0.7/0.6 2.1/1.9

9 93.5 17.9 0.23 7.55 6.5 0.75/0.69 2.75/2.38

10 93.5 17.7 0.23 7.55 9.15 0.82/0.76 3.3/2.87

11 93.5 18 0.23 7.55 12.4 0.9/0.82 4.16/3.6

12 93.5 18 0.23 7.55 14.9 0.94/0.84 4.78/4

13 93.5 17.8 0.23 7.55 6.32 0.71/0.65 2.69/2.33

21 128.5 17.6 0.56 10.75 1.08 0.56/0.57 1.036/1.009

22 127.5 16.9 0.54 10.75 2.48 0.65/0.63 1.274/1.217

23 126.5 17.3 0.54 10.75 4.35 0.67/0.64 1.483/1.371

24 126.5 17.3 0.53 10.75 6.74 0.7/0.67 1.773/1.6

25 125 17.15 0.53 10.75 9.3 0.77/0.74 2.053/1.823

26 125 17.3 0.51 10.75 12.3 0.81/0.76 2.533/2.323

27 125 18.6 0.50 10.75 15 0.82/0.76 2.843/2.433

28 125 17.6 0.49 10.75 9.1 0.74/0.69 2.16/1.903

55 128.5 17 2.0 16.13 1.17 0.51/0.47 0.405/0.405

56 128.5 17.1 2.0 16.13 2.62 0.53/0.5 0.415/0/412

57 127.5 17.6 1.98 16.13 3.7 0.51/0.64 0.5/0.48

58 127.5 17 2.02 16.13 7.38 40.53 40.58

59 127.5 17.1 2.0 16.13 9.9 -/0.51 -/0.64

60 127.5 17 2.0 16.13 13.5 0.67/0.6 0.84/0.74

61 127.5 17.1. 2.0 16.13 14.7 0.69.0.66 0.88/0.77

62 126 17 1.8 16.13 5.86 0.56/0.54 0.605/0.56

4
Indexes 1 and 2 concern to bundle locations with z=0.78-0.98 and z=0.58-0.78

accordingly from the bottom of the model. Qprheat means the power of preheater before

the bundle.

The second series of experiments have been carried out with closed at the bottom

bundle and at pressure P =1.28 MPa. The results of these experiments are presented in

Table 3.

5
Table 3. Experimental data for dosed inlet

Test P, Q, al//a2 (Jg)l/(Jg)2

number MPa kW experiment experiment

12 1.28 5.1 0.39/0.29 0.203/0.146

13 1.28 5.3 0.4/- 0.215/0.154

14 1.28 4.6 0.34/0.26 0.183/0.131

15 1.28 4.9 0.4/0.31 0.198/0.143

16 1.28 6.6 0.485/- 0.28/0.211

17 1.32 6.6 0.43/0.37 0.28/0.211

18 1.32 4.75 -/0.26 0.183/0.134

19 1.32 9.3 0.53/0.44 0.422/0.317

The third series of experiments is presented with only one test in which it was

investigated the behavior of bundle model in modes of partial uncovering and reflooding.

This test was carried out at the following initial parameters: pressure P-1.32 MPa, test

section power Q=9.3 kW, inlet flowrate at reflooding G--9.8g/s, inlet water temperature

Tin = T, -1 K, where T, - saturation temperature.

4. NODALIZATION SCHEME

6
009 Oil

102-10

102-09

102-09

102-07

VIIA102-06

101-10

101-09

101-OS

101-07

101-06

I"Z' W102-05 4105 10145 Pipe bundle

102-04 4.04 101-04

102.-03 4-3 101.03

102-01 .44ILL" 12l-1

002 005

• • 1Preheeter

103-11

Fig. 4 Nodalization scheme of test facility

The nodalization scheme of test facility is shown in Fig. 4. It consists of element

004 "pipe" divided into 10 subvolumes with two heat structures connected to it: 101 -

modeling 55 heated tubes and 102 - modeling the heated shroud. Heat losses heat flux is

determined on the outer surface of the shroud. Element 008 models the volume placed

above the bundle and it is connected to the volume 010 (through the "sngljun" ) in which

were set the conditions of saturated vapor. For the tests without inlet flow volume 010

was connected with volume 012 in which were set the conditions of saturated water.

Element 020 models the preheater and the parameters of flow at its conditions were set in

"tmdpvol" 002 and "tmdpjun" 003. In boiloff test elements 002 and 003 were connected

with pipe 004 ( without preheater).

Heat losses on outer surface of preheater and shroud were set according to

experimental tare as:

Q = 5 (T-293) W - for preheater,

Q = 13.5(T-293) W - for shroud, where T - metal surface temperature (K).

5. RESULTS OF CALCULATIONS FOR STEADY STATE CONDITIONS

Results of calculations and experimental ones for tests with low inlet flowrate and

for pressures P=0.23-0.56 MPa are presented in Table 4 and in Fig. 5. This figure shows

the dependency of a•xat. = f (Jg wemet.) and G-calclatd. = f (Jg Wcuted.), where Jg =

aVg - superficial vapor velocity, (x - void fraction. This figure shows the results of

7
experiments and calculations for tests without inlet flowrate also, which were conducted

at some higher pressure P = 1.32 MPa. One can see that the results of calculations are

closed to experimental ones at Jg < 2 m/s and they are some lower at velocities larger

than 2.5 rn/s.

8
Table 4. Results of calculations and experimental ones for low flowrates

Test a,/a2 cl/a2 (Jg)l/(Jg)2 (Jg)l/(Jg)2

number RELAP experiment RELAP experiment

6 0.581/0.583 0.62/0.52 2.49/2.51 1.4/1.33

7 0.607/0.602 0.66/0.55 2.92/2.82 1.7/1.6

8 0.627/0.624 0.7/0.6 3.51/3.28 2.1/1.9

9 0.657/0.647 0.75/0.69 4.56/4.1 2.75/2.38

10 0.721/0.667 0.82/0.76 5.9/5.27 3.3/2.87

11 0.825/0.662 0.9/0.82 5.88/5.91 4.16/3.6

12 0.82/0.64 0.94/0.84 7.3/6.87 4.78/4

13 0.66/0.65 0.71/0.65 4.5/4.06 2.69/2.33

21 0.547/.55 0.56/0.57 1.98/2.0 1.036/1.009

22 0.577/0.574 0.65/0.63 2.31/2.28 1.274/1.217

23 0.606/0.596 0.67/0.64 2.7/2.61 1.483/1.371

24 0.645/0.623 0.7/0.67 3.18/3.0 1.773/1.6

25 0.678/0.651 0.77/0.74 3.25/3.14 2.053/1.823

26 0.663/0.651 0.81/0.76 4.43/3.97 2.533/2.323

27 0.674/0.662 0.82/0.76 5.03/4.45 2.843/2.433

28 0.652/0.64 0.74/0.69 3.95/3.62 2.16/1.903

55 0.3/0.35 0.51/0.47 0.9/0.93 0.405/0.405

56 0.338/0.381 0.53/0.5 0.99/.0.99 0.415/0/412

57 0.405/0.407 0.51/0.64 1.05/1.03 0.5/0.48

58 0.472/0.456 -/0.53 1.26/1.2 -/0.58

59 0.503/0.483 -/0.51 1.41/1.32 -/0.64

60 0.536/0.514 0.67/0.6 1.62/1.48 0.84/0.74

61 0.545/0.523 0.69.0.66 1.69/1.53 0.88/0.77

62 0.473/0.46 0.56/0.54 1.28/1.24 0.605/0.56

9
1.00-

voidg 0 0

go 00 0 0

0

Z

A

-A

0.40- 0

S V1 -wewkt r

A OVo~iV voio1-egtiuiw(C--O) LAP"

00M - I I

0.oo 20 4 6.00

Fig. 5 Dependence of void fraction from superficial velocity for two levels

for low and zero flowrates and low pressures

Figure 6 shows the results for larger pressures P = 2MPa. In this case the

difference between experimental data and RELAP results are larger and RELAP void

fractions are much lower than experimental values.

0.50

Voidg

0.60 U' oo.• •

~A.-

0.40 AP

A W _ __

AAA 0f

020 o viodgI- 1 AtO9 EV

* Vowd1e'sn

i 0 Vo-eXe2*WWifWM

0o0 ooI- ' I ' I I~

0.00 0.40 0.80 1.20 1.0 2.00

Fig. 6 Results of calculations and experimental ones for low flowrates and

pressure 2 MPa

10
The results of some of this experiments in coordinates a---f(x), where x is

equilibrium quality are presented in Figures 7 and 8.

1.00--

(190-

Ox -

0.80 -

on0 -

Voidg

0

0

0

0

0

0 0

0

P-02M~pa

0 Expeftwft

Qualty

I I i II I I

0.00 00 0.01 0.01 M.01 001

Fig. 7 Dependence of void fraction from equilibrium quality at P=0.23 MPa

00 -

0.60-

0.40

VoIdg

0 0

0

5 0

0

0 S

0

0

* Enn%

Ouafty

0.0 * I

am

' I

0.01

I

0•2 0.00 0.02

Fig. 8 Dependence of void fraction from equilibrium quality at P=2.0 MPa

11
The results for test without inlet flow (G=0) are presented in Fig. 9 and Table 5.

Table 5. Results of calculations and experimental ones for closed inlet

Test number CLI/a2 al/a2 (Jg)l/(Jg)2 (Jg)i/(Jg )2

RELAP experiment RELAP experiment.

12 0.283/0.271 0.39/0.29 0.197/0.153 0.203/0.146

13 0.283/0.28 0.4/- 0.2081/0.165 0.215/0.154

14 0.276/0.256 0.34/0.26 0.164/0.126 0.183/0.131

15 0.279/0.267 0.4/0.31 0.18/0.1407 0.198/0.143

16 0.325/0.304 0.485/- 0.295/0.23 0.28/0.211

17 0.321/0.301 0.43/0.37 0.287/0.223 0.28/0.211

18 0.271/0.261 -/0.26 0.169/0.132 0.183/0.134

19 0.416/0.366 0.53/0.44 0.453/0.242 0.422/0.317

0.80

Voidg

+

+

41:1

0402-

0.2

0~

0

0

+

G=O

*41 -evwiaP

V•01.Vc4e i~hr tni

Vd•2- RB.A•

Vbt:1,VOK:gvmM Unde"

Jg, mIs

0.O0

OL10

' I

0.30

' I

0.40

' I

0.50

Fig. 9 Dependence of void fraction from superficial velocity for closed inlet

It is evident that practically in all cases the calculated values of void fraction are

lower than experimental ones. It is clear that vapor drift calculated by RELAP is larger

than in experiments especially at higher velocities.

12
The next series of calculations were made with the same nodalization scheme but

with using option "bundle" in setting the geometry of "pipe" which models the pipe

bundle. Switching of this option changes the model of vapor drift calculation.

Fig. 10 shows the RELAP and experimental data for low pressures and Fig. 1

for pressure 2 MPa. These data are shown in tables 6 and 7 also.

VOI~ig

00

a.40- P- 0Z3- 054 Wa

4] VdV -F&,Mu 02)- 0 VotW-EL

Jg, nVs

I0 I ' I ' i I

0O0 2W 4W am .W

Fig. 10 Dependence of void fraction from superficial velocity at

P = 0.23 -0.54 MPa

VOIdg 0a A- ULL

cA

A Off 0.0~-

0.0 00 EP 19 n 1.

a WV-44MkuW

OM 0 &W1- m)p

+ VQV-FLM blUre

A VdV.MV&U

aM OAIMW2

Fig. 11 Dependence of void fraction from superficial velocity at P=2.0 MPa for

"bundle" option

13
It is evident that using of drift flux models developed with taking into account of

specific character of two phase flow in rod bundles adjust with experimental data much

better.

The similar results for case of zero inlet flow are presented in Fig. 12.

0L0-

0.60"-

0.40 -

Void9

4.

+.

4.

.0

0

0

÷

Vaid~1 - Oenmeft

Vod1 -RB.AP

VOW92. MAP

WWVedV Vh Mr

Jg, rrifs

0 )

0.30

' I

0.40

' I

0.10

Fig. 12 Dependence of void fraction from superficial velocity at P=2.0 MPa for

"bundle" option

It is evident that in this case the accordance between RELAP data and

experimental ones with using "bundle" option is better also.

14
Table 6. Results of calculations and experimental ones for low flowrates

("bundle" option)

Test al/ia2 ali/a2 (Jg)l/(Jg)2 (Jg)l/(Jg)2

number RELAP experiment RELAP experiment

6 0.567/0.570 0.62/0.52 2.49/2.51 1.4/1.33

7 0.616/0.609 0.66/0.55 2.92/2.82 1.7/1.6

8 0.655/0.645 0.7/0.6 3.51/3.28 2.1/1.9

9 0.729/0.707 0.75/0.69 4.56/4.1 2.75/2.38

10 0.789/0.776 0.82/0.76 5.9/5.27 3.3/2.87

11 0.825/0.797 0.9/0.82 5.88/5.91 4.16/3.6

12 0.851/0.822 0.94/0.84 7.3/6.87 4.78/4

13 0.824/0.79 0.71/0.65 4.5/4.06 2.69/2.33

21 0.630/0.636 0.56/0.57 1.98/2.0 1.036/1.009

22 0.674/0.673 0.65/0.63 2.31/2.28 1.274/1.217

23 0.750/0.711 0.67/0.64 2.7/2.61 1.483/1.371

24 0.802/0.756 0.7/0.67 3.18/3.0 1.773/1.6

25 0.836/0.784 0.77/0.74 3.25/3.14 2.053/1.823

26 0.854/0.819 0.81/0.76 4.43/3.97 2.533/2.323

27 0.860/0.840 0.82/0.76 5.03/4.45 2.843/2.433

28 0.820/0.64 0.74/0.69 3.95/3.62 2.16/1.903

55 0.421/0.425 0.51/0.47 0.9/0.93 0.405/0.405

56 0.461/0.457 0.53/0.5 0.99/.0.99 0.415/0/412

57 0.485/0.476 0.51/0.64 1.05/1.03 0.5/0.48

58 0.567/0.546 -/0.53 1.26/1.2 -/0.58

59 0.615/0.588 -/0.51 1.41/1.32 -/0.64

60 0.67/0.637 0.67/0.6 1.62/1.48 0.84/0.74

61 0.685/0.652 0.69.0.66 1.69/1.53 0.88/0.77

62 0.567/0.55 0.56/0.54 1.28/1.24 0.605/0.56

Table 7. Results of calculations and experimental ones for closed inlet

("bundle" option)

Test number al/a2 al/c2 (Jg)l/(Jg)2 (Jg)l/(Jg)2

RELAP experiment RELAP experiment

12 0.339/0.299 0.39/0.29 0.203/0.146 0.203/0.146

13 0.349/0.313 0.4/- 0.215/0.154 0.215/0.154

14 0.298/0.262 0.34/0.26 0.183/0.131 0.183/0.131

15 0.322/0.285 0.4/0.31 0.198/0.143 0.198/0.143

16 0.519/0.384 0.485/- 0.280/0.211 0.28/0.211

17 0.510/0.384 0.43/0.37 0.280/0.211 0.28/0.211

15
18 0.303/0.268 1-/0.26 10.183/0.134 1 0.183/0.134

19 0.603/0.572 0.53/0.44 0.422/0.317 0.422/0.317

6. RESULTS OF CALCULATIONS FOR BOILOFF TEST AND SENSITIVITY

ANALYSIS

The initial conditions for this test is the same as for test N19 without water supply

from the bottom of test section. An absence of inlet water flow leads to level decreasing

in the upper plenum of test section. After some period of time the level reaches the upper

part of heated pipes and zone of uncovered bundle increases and heatup of tubes begins.

If temperature of pipe tube reaches 555 CO water supply into the bottom part of test

section and reflooding process begins. The flowrate of water is G=9.8 kg/s and its

temperature is T.- - K, where Ts - is saturation temperature.

.Fig. 13 shows the results of calculations and experimental ones for collapsed level

in the test section. The calculations were made for two cases: with and without option

"bundle". The initial values of level are different for these cases because of different

void fraction distribution along the channel. However the time of maximal temperature

reaching is almost the same for both cases. Physical level behavior determined as the time

of wall temperature rising (or dropping at reflood stage) is shown in Fig. 14.

0.00 2M 4.00 6.00 U.D

Fig. 13 Collapsed level behaviour

16
Physical level, m

+0

0

+0

•0

+ 0

0

0+

0+0

0

01

0+

+ + ++ ÷

0.A -

0S Eprmn

0 FaA

+ FaAPw~iM re

I Thne, min I

4.0 6M0 .00

Fig. 14 Physical level behaviour

500.00 -

Tw, C

+.+

+Epiyt

FE- A~P *u

200.00-

7 m IMM I I ' I V 1

0.00 020 DA. 0.0 0.80 1.00

Fig. 15 Rods temperature distribution along the height before the reflooding

stage

17
Fig. 16-20 show the behaviour of pipe bundle wall temperatures for different

locations along the height. The calculated temperatures in the down part of uncovered

zone are some lower than the experimental ones. The calculated temperatures in the

upper part of uncovered zone are conversely higher than the experimental values that

leads to more earlier attainment of maximal temperature and reflooding beginning.

Figure 16 shows the experimental behaviour of wall temperature at Z--0.28 m and

calculated one for two locations nearest to measurement point - for Z=0.25m and

Z=0.35m. It is evident that calculated values are much higher than experimental one. For

more higher locations the difference between experimental and computed values become

smaller and for Z=0.95m (Fig. 20) the accordance between experimental and computed

values becomes good enough for both cases - with using "bundle" option and without it.

4MM.O

3%00-

aiaD -

2M.00

Tw, C

l -- Fl9.APZ-OM

--e- ~ A

-~*-RE.AP Z.02 (b~de)

-A- P~~z US (bwd)

200.a L

-I rTime. mmi

i.00 &OD &00 10.00

Fig. 16 Rod temperature behavior at zf0.28m

18
TWC

0

Time, rain

0.00 z00oo co 42 & 00 SO

Fig. 17 Rod temperature behaviour at z=0.66m

800.0o

Tw, C

Z-MO75 m

* envt 00MI1

e eA -7r

M AP~7na burd~e)

400.00-

0

20.00 -

r n. T~n

1/lfm -" .

0.00

O I

* 4.00 -4.00 &00

Fig. 18 Rod temperature behaviour at z=0.75m

19
*w C OChi

(20 200 4.00 600 8M 10.

Fig. 19 Rod temperature behaviour at zf0.9m

f0,0 200 4.00 00 8.00 1Q00

Fig. 20 Rod temperature behaviour at zf0.95m

20
During the test the upper part of the bundle becomes uncovered and heating of

tubes walls change their electrical resistance and power distribution along the test section.

Fig. 21 shows the results of calculations with taking into account the dependency of the

stainless steel electrical resistance from temperature. One can see that the results for both

cases are almost the same.

0.00 2.00 4.00 6.00 8.00 10.00

Fig. 21 Rod temperature behaviour at zf0.95m with taking into account rod electrical

resistance dependency from temperature.

More important factor for parameters behaviour is the value of upper plenum

volume. It's too difficult to obtain its value from the geometrical data. Fig. 22 shows the

dependence of level behaviour from upper plenum volume. It is evident that V=O.0006

m gives the best result for time of level drop beginning. So all of the calculations were

made with this value.

21
0.80

0.00 2.00 0 6.&00 &00

Fig. 22 Collapsed level behaviour with different upper volume

Another important parameter, which has a large influence on the results, is the

power disturbance between pipe bundle and shroud. Fig.23 shows the results of

calculations for distributions differed from base case - 80% for bundle and 20% for

shroud.

Z-0.95 M

70%-30%

-[ I Time, mlin

am0 22 4D M RO 00

Fig. 23 Rod temperature behaviour at zf0.95m with different power

distribution between rods and shroud

22
The influence of presence of six insulator rods is very small what is illustrated at

Fig. 24.

C100 IOD -C~OD 6 0 O

Fig. 24 Rod temperature behaviour at zf0.95m with taking into account

presence of insulators

Besides that it was checked the influence of such parameters as temperature of

water supplied into the upper plenum in the regimes without inlet flow and heat loss also.

The calculations showed the influence of this value is very small also excluding the tests

with very small inlet flowrates, when bundle power is the same order as the heat losses.

As for shroud temperature it was found the significant discrepancies between

computed and measured values. Fig. 25-26 show the results of calculations and

experimental ones for two locations of the test section. These calculations were made for

two cases differed by power distribution between pipe bundle and shroud. The base case

this distribution was 20% shroud power and the second - 30% shroud power. It is evident

that this factor has small influence on the shroud temperature behaviour.

23
320.00-

240.00-

2DD.00

-eL--A-

-4F FUJPE*ý

160.00 I ' I I I

2.00 4.00

I I I T I f - 6OD too MOD0

Fig. 25 Shroud temperature behaviour at zf0.35m

-*-RELAP -3%

0

M

we

0

0

3MOOD

OO

200.OD

0.00 2-00. 4.00 6.00 M00 10,00

Fig. 26 Shroud temperature behaviour at z=0.88m

24
Another factor that could have an influence on the shroud temperature behavior is

the heat losses value on its outer surface. Fig. 27-29 shows the results of calculations

carried out with heat losses reduced by 20%. As one expect the shroud temperature

becomes some larger, what illustrated by Fig. 27 for upper part of the shroud (Z=0.88m).

For bottom part of the shroud the temperatures changed insignificantly and difference

between experimental and computed temperature remains at former level (Fig. 29).

3WJ

T StrOL4 C

0.

a

ID

S

-UZ=OM mu

Expdment

RELAP5 with 1.0 QOoss

RELAP wft 0.8 01=e

M0

0.00 2-0 4.Z0 6.0 8.0 10.00

Fig. 27 Shroud temperature behaviour at z=O.88m with different heat losses

25
O2.0 M4M 6. 8M 10,O0

Fig. 28 Rod temperature behaviour at z=0.95m with different heat losses

T shroud, C

Z=0.35m

I 0 Evenmerit S-e-- RELAPwk 1.0 oss

- REAPwkhO.8 Ms

240MO

CLOD 2.00 4M 6.00 8D 10,0

Fig. 29 Shroud temperature behaviour at z=0.35m with different heat losses

26
7. RUN STATISTICS

RELAP5/MOD3.2 code efficiency is illustrated by Fig. 30-31 where time step

variation and CPU time during the calculation are presented. Grind time is evaluated as

CPU/(C*DT) = 0.00098 , where

C= 12 - volumes number,

DT = 8632 - time steps number,

CPU = 110 s - CPU time.

0.12

0.10

ODS

DTSTEP, s

Time, s

81M0

Fig. 30 Time step behaviour during boiloff and reflood test

27
120.00 CPU time, 3

80.00-

40.00

"Time, s

0.0 - I I- I I I

0.00 200.0 400.00 600.00 800A0

Fig. 31 CPU time during the test calculation

8. CONCLUSIONS

RELAP5/MOD3.2 assessment for processes proceeding in the rod bundle model

with tight lattice was made. First series of the investigated experiments have been

conducted at steady state conditions at small or zero flowrates at the inlet of the bundle.

The comparison of computed with RELAP5/MOD3.2 results with experimental ones

showed that for such processes code gives rather good results. The comparison of

computed and experimental results for process of boil-off and reflooding shows that there

is a good coordination between computed and experimental values between temperatures

of pipe bundle walls for upper part of the bundle. For lower part of the bundle there are

some discrepancies between computed and experimental values of temperature, the later

being some lower than experimental ones. The calculated values of shroud temperature

were rather less than experimental ones.

28
APPENDIX: RELAP5 INPUT DECK FOR BOILOFF AND REFLOOD TEST

=* CKTI boiloff test

0000100 new transnt

* time 1 time2

0000105 5.0 10.0

0000110 air ,

* time step control data

* end time min dt max dt optn mnr mjr rst

0000202 100.0 1.0-9 0.10 00003 10 10000 100000

0000203 265.0 1.0-9 0.10 00003 10 10000 100000

0000204 300.0 1.0-9 0.10 00003 10 10000 100000

0000205 400.0 1.0-9 0.10 00003 10 10000 100000

0000206 800.0 1.0-9 0.10 00003 10 10000 100000

*301 void 004070000

301 voidg 004070000

302 voidg 004090000

303 cntrlvar 02 * Ggl

304 cntrlvar 01 *WGg2

305 cntrlvar 04 *Wg01 306 cntrlvar 03 *WgO2

307 cntrlvar 05 *Mloss all

308 cntrlvar 06 *1loss 1

309 cntrlvar 16 *Level

310 emass 0 *

311 mflowj 005000000 * outflow

312 tmass 0

313 dt 0

314 cntrlvar 14 *core mass

* max clad temperature greater than 820 K

0000501 cntrlvar 015 ge null 0 820.0 1

0020000 inleta tmdpvol * AAAAAAAAAAAAAAAAAAA

* area lengh volume azim. ang ver ang elev

0020101 0.0 10.0 10.0 0.0 0.0 0.0

* rough h. diamn fe

0020102 4.e-5 0.0 00 ,

* ebt

0020200 003

* time press temp

0020201 0.0 1.32e6 464.46

29
*1~

0020202 500.0 1.32e6 464.46

0030000 inlet tmdpjun * AAAAAAAAAAAAAAAAAA

* from to area

0030101 002000000 004000000 1.249e-3

0030200 1 501

* h liq flow vap flow int vel

0030201 0.0 00.Oe-3 0.0 0.0

0030202 0.1 9.8e-3 0.0 0.0

0030203 1000.0 9.8e-3 0.0 0.0

* component 4

* core

0040000 core pipe * AAAAAAAAAAAAAAA

0040001 10 * nvol

* vol area vol no

0040101 1.249e-3 10

* jun area jun no

0040201 1.072e-3 I ** grid

0040202 1.249e-3 2

0040203 1.072e-3 3 ** grid

0040204 1.249e-3 4

0040205 1.072e-3 5 **grid

0040206 1.249e-3 6

0040207 1.072e-3 7 ** grid

0040208 1.249e-3 8

0040209 1.072e-3 9 -*grid

* vol length vol

0040301 0.1 01

0040302 0.1 02

0040303 0.1 03

0040304 0.1 04

0040305 0.1 05

0040306 0.1 06

0040307 0.1 07 * void2

0040308 0.1 08

0040309 0.103 09 *voidl

0040310 0.103 10

* aver vol no

0040601 90.0 10

* rough dhy vol no

30
0040801 1.0-3 3.77e-3 10

* floss floss Jun no

0040901 0.49 0.49 1

0040902 0.00 0.00 2

0040903 0.49 0.49 3

0040904 0.00 0.00 4

0040905 0.49 0.49 5

0040906 0.00 0.00 6

0040907 0.49 0.49 7

0040908 0.00 0.00 8

0040909 0.49 0.49 9

* pvbfe vol no

0041001 01000 10

0041001 01100 10 *bundle

* fvcahs jun no

0041101 001000 9

* ebt p t volno

0041201 003 1.32533e6 465.645 0.0 0.0 0.0 1

0041202 003 1.32466e6 465.622 0.0 0.0 0.0 2

0041203 003 1.32404e6 465.601 0.0 0.0 0.0 3

0041204 003 1.32343e6 465.579 0.0 0.0 0.0 4

0041205 003 1.32285e6 465.560 0.0 0.0 0.0 5

0041206 003 1.32229e6 465.540 0.0 0.0 0.0 6

0041207 003 1.32176e6 465.522 0.0 0.0 0.0 7

0041208 003 1-32124e6 465.504 0.0 0.0 0.0 8

0041209 003 1.32075e6 465.487 0.0 0.0 0.0 9

0041210 003 1.32025e6 465.470 0.0 0.0 0.0 10

0041300 0 * ctrl word

* flowf flowg win jun no

0041301 0.0 0.0 0.0 9

0050000 uppl sngljun

* from to area floss floss fvcahs

0050101 004010000 006000000 1.072e-3 0.5 0.5 001000

0050101 004010000 008000000 1.072e-3 0.5 0.5 001000

* flowf flowg win

0050201 1 0.0 0.0 0.0

*---6- -7

*0060000 up snglvol

*0060101 6.32e-4 0.065 0.0000 0.0 90.0 0.065

** pvbfe *0060102 4.0-5 0.0 01000

*0060200 003 1.32+6 465.2 0.0 0.0 0.0 **:

*0070000 uppl sngljun

from to area floss rloss fvcahs

31
*0070101 006010000 008000000 2515.e-6 0.155 0.155 101000

** flowf flowg win

*0070201 1 00.0e-3 0.0 0.0 **

* * _ -2 1 -- -- -- 3-- ------ -- . .. 6 - --- 7

0080000 up snglvol

0080101 20.0e-4 0.165 0.0 0.6e-4 90.0 0.165

* hf

0080102 4.0-5 0.0 01000

0080200 003 1.32+6 465.2 0.0 0.0 0.0

0090000 uppl sngljun

* D=l8mm

* from to area floss rloss fvcahs

0090101 008010000 010000000 254.34e-6 2.0 2.0 000000*

* flowf flowg win

0090201 1 00.0e-3 0.0 0.0

0100000 outlet tmdpvol . AAAAAAAAAAAAAAAAAM

* area lengh volume azim. ang ver ang elev

0100101 0.0 10.0 10.0 0.0 0.0 0.0

* rough h. diam

0100102 4.e-5 0.0 00000

0100200

0100201

0100202

ebt

002

time press temp

0.0 1.32e6 1.00

500.0 1.32e6 1.00

*

*°

HEAT STRUCTURES

bundle

* - - - - - - - - - - - - - - - - - - -

10101000

10101100

10101101

10101201

,nh np geomn st-st left

10 4 2 0 2.0e-3

0 1

3 3.0e-3

004 3

10101301 1.0 3

10101401 467.5 4

32
10101501 0

10101502 0

10101503 0

10101504 0

10101505 0

10101506 0

10101507 0

10101508 0

10101509 0

10101510 0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

I

I

I

1

1

1

I

I

5.5 1 *(0.1*55tubes=5.5)

5.5 2

5.5 3

5.5 4

5.5 5

5.5 6

5.5 7

5.5 8

5.655 9

5.655 10 *(0.103*55=5,655)

10101601 004010000 0

10101602 004020000 0

10101603 004030000 0

10101604 004040000 0

10101605 004050000 0

10101606 004060000 0

10101607 004070000 0

10101608 004080000 0

10101609 004090000 0

10101610 004100000 0

I

1

1

1

1

1

1

1

I

1

1 5.5 1

1 5.5 2

1 5.5 3

1 5.5 4

1 5.5 5

1 5.5 6

1 5.5 7

1 5.5 8

1 5.655 9

1 5.655 10

10101701 100 0.1 0 0 10 *

* left chf hf lhb gslf gslr glcf gcr bf no

10101801 0.0 10.0 10.0 0.0 0.0 0.0 0.0 1.0 10

10101901 6.0e-3 10.0 10.0 0.0 0.0 0.0 0.0 1.0 10

* shroud

*----------------------------------------------------

* nh np geom st-st left

10201000 10 4 2 0 30.5e-3

10201100 0 1

10201101 3 31.5e-3

10201201 004 3

10201301 1.0 3

10201401 465.5 4

10201501 004010000 0 1 1 0.1 1

10201502 004020000 0 1 1 0.1 2

10201503 004030000 0 1 1 0.1 3

10201504 004040000 0 1 1 0.1 4

10201505 004050000 0 1 1 0.1 5

10201506 004060000 0 .1 1 0.1 6

10201507 004070000 0 1 1 0.1 7

10201508 004080000 0 1 1 0.1 8

10201509 004090000 0 1 1 0.103 9

10201510 004100000 0 1 1 0.103 10

33
10201601

10201602

10201603

10201604

10201605

10201606

10201607

10201608

10201609

10201610

-700

-700

-700

-700

-700

-700

-700

-700

-700

-700

O 3701 1 0.1 1

0 3701 1 0.1 2

0 3701 1 0.1 3

0 3701 1 0.1 4

0 3701 1 0.1 5

0 3701 1 0.1 6

0 3701 1 0.1 7

0 3701 1 0.1 8

0 3701 1 0.1039

0 3701 1 0.103 10

10201701 101 0.1 0 0 10 *

• left chf lhf lhb gslf gslr glcf gcr bf no

10201801 0 10.0 10.0 0.0 0.0 0.0 0.0 1.0 10

10201901 0.0 10.0 10.0 0.0 0.0 0.0 0.0 1.0 10

• heat structure thermal property data

• mtl.type th.con htcap

20100400 tbl/fctn 1 1 * tube.(gamma=7.9 g/cm*cm*cm)

• thermal conductivity tube

*crduo temp th.con.

20100401 273.15 15.3

20100402 373.15 16.9

20100403 473.15 18.1

20100404 573.15 19.5

20100405 673.15 20.3

20100406 800.15 21.6

20100407 900.15 23.3

20100408 1000.15 25.0

• volumetric heat capacity tube

*crdno temp htcap.

20100451 273.15 3.803+6

20100452 373.15 3.903+6

20100453 473.15 4.063+6

20100454 573.15 4.234+6

20100455 673.15 4.329+6

20100456 800.15 4.329+6

20100457 900.15 4.329+6

20100458 1000.15 4.210+6

* general tables

34
* power table

* Q total=9.3 kW for test 3D (0.8)

*erdno name trip

20210000 power 501 ,

*crdno time power Wt

20210001 0.0 0.744e4

20210002 0.1 0.744e4

* power table shroud (20%)

*crdno name trip

20210100 power 501

*crdno time power wt

20210101 0.0 0.1860e4

20210102 5.0 0.1860e4

*

* power table preheater

*crdno name trip

20210200 power 501

*crdno time power wt

20210201 0.0 7.55e3

20210202 1.0 7.55e3 *

20210203 10.0 7.55e3

20210204 500.0 7.55e3

*

*

temperature in containment AAAAAAAAAAAAAAAAAAAAAA~AAM

20270000 temp

20270002

20270003

20270004

0.0 300.0

1.0 300.0

1.0e6 300.0

20270100 htc-t 0 1.0 1.0

* Q core= 13.5*(t-20)=13.5*(465.5-300)=2234

20270101 -1.0 64.381 *core

20270102 0.0 64.381 *h=Q/dt/(3.14*D*L)

20270102 0.0 64.381 * h=13.5/3.14/63e-3/1.06=64.381

20270103 1.0 64.381.

20270104 10000.0 64.381

20270200 htc-t 0 1.0 1.0 *preheater

35
20270201 -1.0 50.55 * h=Q/(3.14 D L)= 5/3.14/63e-3/0.5

20270202 0.0 50.55

20270203 100.0 50.55

20500100 GG2 mult 1.249e-3 0.0 0

20500101 rhogi 004070000

20500102 velgi 004070000

20500103 voidgj 004070000

20500200 GGI mult 1.249e-3 0.0 0

20500201 rhogj 004090000

20500202 velgi 004090000

20500203 voidgj 004090000

20500300 WOGI mult 1.0 0.0 0

20500301 velgj 004090000

20500302 voidgj 004090000

20500400 WOG2 mult 1.0 0.0 0

20500401 velgj 004070000

20500402 voidgj 004070000

20500500 "Hloss" sum -0.19782e-3 0 1

20500501 0.0 0.1 htrnr 020100101

20500502 0.1 htrnr 020100201

20500503 0.1 htrnr 020100301

20500504 0.1 htrmr 020100401

20500505 0.1 htrnr 020100501

20500506 0.1 htrnr 020100601

20500507 0.1 htLrnr 020100701

20500508 0.1 htrnr 020100801

20500509 0.103 htmr 020100901

20500510 0.103 htmr 020101001

• S = 3.14*D*dz=- 3.14*63/1000*dz=0.19782 *dz m2

20500600 "Qbun" sum 0.01884 0 1

20500601 0.0 5.5 htmr 020100101

20500602 5.5 htrnr 020100201

20500603 5.5 htmr 020100301

20500604 5.5 htrnr 020100401

20500605 5.5 htrnr 020100501

20500606 5.5 htrmr 020100601

20500607 5.5 htmr 020100701

20500608 5.5 htmr 020100801

20500609 5.655 htmr 020100901

20500610 5.655 htrnr 020101001

• S = 3.14*d*dz= 3.14*6e-3*dz=-0.01884 *dz m2

20500700 "Qshr' sum 0.19782 0 1

20500701 0.0 0.1 htrnr 020100100

20500702 0.1 htrnr 020100200

20500703 0.1 htrnr 020100300

36
20500704 0.1 htrnr 020100400

20500705 0.1 htrnr 020100500

20500706 0.1 httir 020100600

20500707 0.1 htmr 020100700

20500708 0.1 htmr 020100800

20500709 0.103 htrnr 020100900

20500710 0.103 htrnr 020101000

* S = 3.14*D*dz- 3.14*63/1000*dz=0.19782 *dz m2

20500800 q sum 0.769 0. 1

20500801 0.0 1.0 cntrlvar 06 * Qrods+Qshroud

20500802 1.0 cntrlvar 07

* q = Q(Ph*L)= (cntrlvar 8)/[3.148(61e-3+6e-3*55)*1.06] =

* = (cntrlvar 8)/1.3= 0.769*(cntrlvar 8)

* Ph= 3.14*(61e-3+6e-3*55) =1.227

* dM~I/dt- -q*Ph*L/r

* name type scale init flag

20500900 r sum 1.0 0. 1

20500901 0.0 1.0 sathg 004010000

20500902 -1.0 sathf 004010000

* Ph*IJr

* Ph*L= 1.277*1.06=1.3

20501000 "Ph*L/r" div 1.3 0.0 1

20501001 cntrlvar 09

* init value

20501100 Int" integral-1.0 0.0 1

20501101 cntrlvar 08

20501200 "Mlout" mult 1.0 0.0 1

20501201 cntrlvar 10 cntrlvar 11

* name type scale init flag

20501300 "Mliq" sum 1.0 0.76 1

20501301 0.76 1.0 cntrIvar 12

* Mass--rho*Lev*s

* name type scale init flag

20501400 "Mcore" mult 1.249e-3 0.0 1

20501401 rhof 004010000 cntrlvar 16

37
* max clad temperature

20501500 maxtemp stdfncm 1.0 0.0 1

S AAAAAAAAAAAAAAAAMA

20501501 max httemp 010100104

20501502 httemp 010100204

20501503 httemp 010100304

20501504 httemp 010100404

20501505 httemp 010100504

20501506 httemp 010100604

20501507 httemp 010100704

20501508 httemp 010100804

20501509 httemp 010100904

20501510 httemp 010101004

*

20501600 corelev sum 1.0 0.0 1 * AAAAAAAAAAAA

20501601

20501602

20501603

20501604

20501605

20501606

20501607

20501608

20501609

20501610

0.0 0.1 voidf 004010000

0.1 voidf 004020000

0.1 voidf 004030000

0.1 voidf 004040000

0.1 voidf 004050000

0.1 voidf 004060000

0.1 voidf 004070000

0.1 voidf 004080000

0.103 voidf 004090000

0.103 voidf 004100000

20501700 vesslev sum 1.0 0.0 1 * AAAAAAAAAAAA

20501701"

20501702

20501703

20501704

20501705

20501706

20501707

20501708

20501709

20501710

20501711

0.0 0.1 voidf 004010000

0.1 voidf 004020000

0.1 voidf 004030000

0.1 voidf 004040000

0.1 voidf 004050000

0.1 voidf 004060000

0.1 voidf 004070000

0.1 voidf 004080000

0.103 voidf 004090000

0.103 voidf 004100000

0.1586 voidf 008010000

20502000 Gdown mult 1.072e-3 0.0 0

20502001 rhof 005000000

20502002 velt 005000000

20502003 void4 005000000

20502100 "liqdown" integral 1.0 0.0 1

20502101 cntrlvar 20

38
20502200 Gvout mult 254.34e-6 0.0 0

20502201 rhogj 009000000

20502202 velgj 009000000

20502203 voidgj 009000000

20502300 "Gvout" integral 1.0 0.0

20502301 cntrlvar 22

* name type scale init flag

20501900 "Mass" sum 1.0 0. 1

20501901 0.0 1.0 tmass 0

20501902 -1.0 cntrlvar 23

39

NRC FORM 33 ULS NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER (2-M(ignd by NRC, Ad Vol, Supp.. Rwv. F3=,1,3 BIBUOGRAPHIC DATA SHEET

2. TrrE AND szm'mJ NUREGAA-0168

Assessment of RELAP5lMOD3.2 for Thehmohydraulic Processes in

Heated Rod Bundles With Tight Lattice at CKTI Test Faclity 3. DATE REPORT PU YSHED

October 1999

4. FIN OR GRANT NUMBER

S. AUJThOR(S) 6. TYPE OF REPORT

A.S. Devkin Technical

7. PERIOD COVERED Prdi Dabs)

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (VNRC, pvoe Dvam O arfUimogk, U.S. MAswRucfL6y Cordamn arndp7. addrmes Ic&nrbr,

P-%- emed f-q am-es)

Nuclear Safety Institute

Russian Research Center"Kurchatov Institute"

123182, Moscow

Russia

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (VMzc, W'Same above lcanfrwtdv.MDwxxyn. aofegor , U.S. ,kwwRgbe, yCan•y•3y ,

and medfdf ss.)

Division of System Analysis and Regulatory Effectiveness

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washinaton. DC 20555-0001

10. SUPPLEMENTARY NOTES

11. ABSTRACT W0 wd.• a-rks)

This report presents the results of RELAP5/MOD3.2 assessment in the predction of two-phase hydrodynamics and heat transfer in

rod bundle model with Ight lattice. The experiments have been carried out at the CKT1 (St. Petersburg) test facility. The

peculiarities of these researches were the non-standard geometrical characteristics of the 55-rod bundle - dose packed assembly

and small hydraulic diameters, and also the parameters -small flow rates (down to zero) and low pressure (from 0.23 up to 2.0

MPa). The assessment of RELAP5/MOD3.2 code was done for two cases: for steady state conditions at small or zero flowrates at

the inlet of the rod bundle and for boil-off and reflooding processes. The comparison of calculated results with experimental ones

shows that there was a good coordination between computed and experimental values of void fractions and bundle wall

temperatures for almost all the tests.

12. KEY WORDSIOESCRIPTORS WLf wacrs a epasw Nt wiW as.bt mewchew in fte.g me a•po) 13. AVALABILITY STAIEMENT

RELAP5 unlimited

Rod Bundles 14. SECURITY CLASSIFICATION

CKTI Test Facilfty (ri, n,) • 

Assessment unclassified

r's PuA-)

unclassified

15. NUMBER OF PAGES

16. PRICE

NRC FORM 335 t24)
Federal Recycling Program

NUREG/IA-0168 ASSESSMENT OF RELAPS/MOD3.2 FOR THERMOHYDRAULIC PROCESSES IN

HEATED ROD BUNDLES WITH TIGHT LATTICE AT CKTI TEST FACILITY

OCTOBER 1999

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, DC 20555-0001

FIRST CLASS MAIL

POSTAGE AND FEES PAID

USNRC

PERMIT NO. G.67

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

CL

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