NUREG/IA-0006

Intemational

Agreement Report

Assessment of RELAP5/MOD 2

Against Marviken Jet Impingement

Test 11 Level Swell

Prepared by

0. Rosdahl, D. Caraher

Swedish Nuclear Power Inspectorate

P.O. Box 27106

S102 #52 Stockholm, Sweden

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555

September 1986

Prepared as part of

The Agreement on Research Participation and Technical Exchange

under the International Thermal-Hydraulic Code Assessment

and Application Program (ICAP)

Published by

U.S. Nuclear Regulatory Commission
NOTICE

This report was prepared under an international cooperative

agreement for the exchange of technical information.' Neither

the United States Government nor any agency thereof, or any of

their employees, makes any warranty, expressed or implied, or

assumes any legal liability or responsibility for any third party's

use, or the results of such use, of any information, apparatus product or process disclosed in this report, or represents that its use

by such third party Would not infringe privately owned rights.

Available from

Superintendent of Documents

U.S. Government Printing Office

P.O. Box 37082

Washington, D.C. 20013-7082

and

National Technical Information Service

Springfield, VA 22161
NUREG/IA-0006

International

Agreement Report

Assessment of RELAP5/MOD 2

Against Marviken Jet Impingement

Test 11 Level Swell

Prepared by

0. Rosdahl, D. Caraher

Swedish Nuclear Power Inspectorate

P.O. Box 27106

S102 #52 Stockholm, Sweden

Office of Nuclear Regulatory Research ..U.S. Nuclear Regulatory Commission

Washington, D.C. 20555

September 1986

Prepared as part of The Agreement on Research Participation and Technical Exchange under the International Thermal-Hydraulic Code Assessment and Application Program (ICAP)

Published by

U.S. Nuclear Regulatory Commission
NOTICE

This report documents work performed under the sponsorship of the SKI/STUDSVIK

of Sweden. The information in this report has been provided to the USNRC

under the terms of an information exchange agreement between the United States

and Sweden (Technical Exchange and Cooperation Arrangement Between the United

States Nuclear Regulatory Commission and the Swedish Nuclear Power

Inspectorate and Studsvik Enerigiteknik AB of Sweden in the field of reactor

safety research and development, February 1985). Sweden has consented to the

publication of this report as a USNRC document in order that it may receive

the widest possible circulation among the reactor safety community. Neither

the United States Government nor Sweden or any agency thereof, or any of their

employees, makes any warranty, expressed or implied, or assumes any legal

liability of responsibility for any third party's use, or the results of such

use, or any information, apparatus, product or process disclosed in this

report, or represents that its use by such third party would not infringe

privately owned rights.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Project 85026, Ref 13.3-917/84

Swedish Nuclear Power Inspectorate

Osten Rosdahl

David Caraher*

ICAP

ASSESSMENT OF RELAP5/MOD2 AGAINST MARVIKEN

JET IMPINGEMENT TEST 11 LEVEL SWELL

ABSTRACT

RELAP5/MOD2 simulations of level swell of saturated liquid in a large (5 m diameter, 22 m high)

vessel are reported. For certain nodalizations

RELAP5 is shown to predict the measured void

fraction profile with fair accuracy. RELAP5 results are shown to be dependent upon nodalization

with the accuracy of computed results deteriorating significantly when a large number of nodes

is employed.

* Engineering Software Consulting

Approved

iii

STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

LIST OF CONTENTS

Page

EXECUTIVE SUMMARY 1

1. INTRODUCTION 4

2. FACILITY AND TEST DESCRIPTION 6

3. CODE AND MODEL DESCRIPTION 10

3.1 Input description 10

4. RESULTS AND DISCUSSION 12

4.1 Base case 12

4.2 Nodalization studies 18

4.3 Time step studies 19

5. COMPUTATIONAL EFFICIENCY 31

6. CONCLUSIONS 32

7. REFERENCES 34

APPENDIX

v

7

STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 1

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EXECUTIVE SUMMARY

RELAP5/MOD2 simulations have been conducted for

MARVIKEN Jet Impingement Test 11 (JIT 11). The

purpose of the simulations was to assess the

ability of RELAP5/MOD2 to simulate level swell

in a large vessel.

The experimental facility consisted of a large

vessel 5.2 m in diameter and 22 m high having a

total volume of 420 m 3 . A standpipe 1 m in diameter and 18 m tall was inserted in the vessel.

A discharge pipe containing a valve, nozzle, and

rupture disks was attached to the lower end of

the standpipe at the bottom of the vessel.

The vessel was filled to the 10.2 m elevation

with nearly saturated liquid; the remaining part

of the vessel and the standpipe were filled with

saturated steam. The initial pressure in the

vessel was 5.0 MPa.

The test was initiated by breaking the rupture

disks. Because of the standpipe only steam flowed

from the vessel. Differential pressures were recorded at various elevations in the vessel, thus

affording a history of fluid density versus elevation to be obtained. Discharge mass flow rate

was also measured. The experiment was terminated

when the pressure in the vessel reached 1.9 MPa.

After the rupture disks broke bulk flashing occurred in the liquid. The level of the resulting

two phase mixture rose rapidly and reached a

maximum height of about 18 m - the top of the

standpipe - within 15 seconds. The mixture level

declined slowly thereafter receding to near the
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 2

1986-07-11

14 m elevation by the time the test ended

(80 seconds). For elevations below the 13 m

height the differential pressure measurements

remained fairly constant over the 15 to 80 second

time period; indicating that the void fraction

was fairly constant.

RELAP5/MOD2 simulations were conducted using 20,

40 and 100 nodes to model the annular region in

the vessel below the top of the standpipe. The

experimental mass flow rate was used as a boundary condition. Differential pressures calculated

by RELAP5 were compared to measured ones.

The 20 node and the 40 node simulations showed

similar results. Both calculations indicated that

the RELAP5 underpredicted the void fraction of

the swelled two phase mixture for elevations

below 13 m and overpredicted the void fraction

for higher elevations. The results imply that

the interfacial drag force in RELAP5 fell off

too rapidly with increasing void fraction. Consequently RELAP5 carried less liquid to the upper

elevations than was actually carried there and

RELAP5 allowed the liquid to drain from the upper

elevations somewhat faster than it actually did.

The 100 node simulation was characterized by very

erratic differential pressure histories which

were, for some elevations, much different from the

dP histories of the 20 and 40 node cases. Moreover, the 100 node simulation was found to be

sensitive to time step size - changing the step

size from 0.1 s to 0.05 s (material Courant

limit = 0.12 s) produced large changes in void

fraction profiles. The behaviour of the 100 node

simulation is believed to be related to the
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 3

1986-07-11

interphase drag model in RELAP5 - its strong

dependence on void fraction in the bubble-toslug flow transition region; its explicit connection to the numerical solution; and its

algorithm for damping large changes in computed

values.

Time step studies on the 20 node model revealed

that the RELAP5 calculation was sensitive to time

step size during the time period (0-30 s) when

the level swelled to its maximum height.

The 20 and 40 node simulations have demonstrated

that RELAP5/MOD2 can give a fairly accurate simulation of the void profile occurring during level

swell in large vessels. Improvements in the

RELAP5 interphase drag model could lead to better

simulations but would probably sacrifice the generality of the present model.

The 100 node simulation has demonstrated that

the RELAP5 solution does not converge with increasing nodalization - at least not for time

step sizes allowed by RELAP5's automatic time

step control algorithm. The results suggest that

at some level of nodalization the numerical

models for smoothing locally computed variables

begin to overshadow the physics.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 4

1986-07-11

1. INTRODUCTION

The International Thermal-Hydraulic Code Assessment and Applications Program (ICAP) is being

conducted by several countries and coordinated

by the USNRC. The goal of ICAP is to make quantitative statements regarding the accuracy of the

current state-of-the-art •. armal-hydraulic computer programs developed under the auspices of

the USNRC.

Sweden's contributions to ICAP relate both to

TRAC-PWR (1) and RELAP5 (2). The assessment calculations are being conducted by Studsvik Energiteknik AB for the Swedish Nuclear Power Inspectorate. The assessment matrix is shown in

Table 1-1.

This report presents the results of an assessment

of RELAP5's ability to calculate level swell. In

particular, Jet Impingement Test lI(JIT 11) has

been simulated using RELAP5. JIT 11 was one of a

series of full scale jet impingement experiments

conducted at the Marviken power station, Marviken, Sweden, during 1981.

This report is organized as follows: section 2

describes the experimental facility and section 3

describes the RELAP5 model used to simulate the

experiments. In section 4 results from the simulations are presented and discussed. Computational

efficiency of RELAP5 and numerical problems encountered during the simulations are given in

section 5. Conclusions are presented in section 6.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

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5

Table 1

ICAP Assessment Matrix - Sweden.

Code Facility Type Description

Sep effect Integral

RELAP5 Marviken2l X Subcooled Critical Flow

RELAP5 Marvikenli X Critical Fl.w, ".vel swell

RELAP5 FIX-Il X Recirculation Line ( 10 %) break

RELAP5 FIX-II x Recirculation Line (31 %) break

RELAP5 FIX-II X Recirculation Line (200 %) break

RELAP5 LOFT x Cold Leg Break (438) pumps off

RELAPS LOFT X Cold Leg Break (4") pumps on

RELAPS FRIGG X Subcooled Void Distribution

RELAP5 FRIGG X Critical Heat Flux

REIAP5 RIT X Post Dryout Heat Transfer

TRAC/PF1 Ringhals X Loss of Load
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 6

1986-07-11

2. FACILITY AND TEST DESCRIPTION

The Marviken Power Plant was built as a boiling

heavy water direct cycle nuclear reactor but was

never commissioned. The nuclear steam supply

system was left intact and an oil fired boiler

was built to provide steam for the turbine. During 1981 and 1982 Marviken was the site of the

Jet Impingement Test (JIT) program. One of the

tests, JIT 11, examined the flow of steam from

the Marviken vessel onto a test plate. Differential pressure measurements made in the vessel

during JIT 11 provided data regarding the level

swell occurring in the vessel as steam flowed

out of the vessel.

Figure 2-1 depicts the Marviken pressure vessel

and the location of the differential pressure

measurements. For JIT 11 a standpipe was inserted

into the vessel to ensure that only steam flowed

out of the vessel. The outlet nozzle was located

beneath the vessel. The piping leading to the

nozzle and the nozzle are depicted in Figure 2-2.

Initial and boundary condition for JIT 11 are

summarized in Table 2-1. A complete description

of the experimental facility for the JIT program

is given in Reference 3. A description of JIT 11

is presented along with test results in Reference 4.

The probable error (one standard deviation) in the

measured differential pressure values shown in this

report is 0.6 kPa; the 99 % confidence error is

1.5 kPa.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

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7

Table 2-1

Important parameters for Marviken JIT 11.

Vessel volume (net internal)

Vessel inside diameter

Stand pipe:

height

outside diameter

wall thickness

Discharge nozzle:

diameter

area

length

Initial pressure

Final pressure

Initial water level

Final water level

Initial inventory:

water

steam

420 m3

5.22 m

18 m

1.04 m

8.8 mm

0.299 m

702 x 10-4 m2

1.18 m

5.0 MPa

1. 88 MPa

10.2 m

8.0m

145 x l03 kg

5 x l03 kg
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

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8

20

18 . STAND PIPE

LEVEL

16

14

12

I I0

ci,

F -8 I'-

z

-6

_j

-aJ

-. J

14

2

-a0

I-INITIAL LEVEL

F- FINAL LEVEL

Figure 2-1

Marviken test vessel. Differential pressure

transducers A through J, internal standpipe and

initial (I) and final (F) inventory level are

shown for Test T-11.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

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9

System

Reference leve Connection piece

Instrumentation ring I

pipe spool

Instrumentation ring II

Ball valve

Rupture discs

Downstream pipe spool

1) All dimensions are in millimeters at room temperature.

2) Not to scale

(JET)

Figure 2-2

Arrangement of components in the discharge pipe.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 10

1986-07-11

3. CODE AND MODEL DESCRIPTION

The simulations of JIT 11 were made with RELAP5/

MOD2, cycle 36.02.

3.1 Input description

The RELAP5 model of the Marviken vessel is shown

in Figure 3-1. The standpipe was modelled by a

single volume pipe component. At its upper end,

this pipe was connected to a branch component

which corresponded to the vessel region from the

top of the standpipe to 0.5 m above the standpipe. The upper region of the vessel was modelled by a pipe component having 3 volumes.

The annular vessel region lying below the top of

the standpipe was modelled as an annulus component. For the base case this component was divided into 20 nearly equally sized volumes. For

nodalization studies the number of cells in this

component was increased to 40 and then to 100.

A mass flow rate boundary condition was applied

to the lower end of the component representing

the standpipe. The boundary condition was taken

from the experimental data.

The RELAP5 control system was used to calculate

differential pressures for comparison with experimentally measured ones. In constructing the control system it was assumed that the pressure,

which is a point quantity in RELAP5, varied linearly between the midpoints of adjacent cells.

With this assumption pressure could be calculated at the exact location of each of the differential pressure taps. The assumption is a

good one as long as the pressure variation with
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

11

elevation is dominated by the gravity head of

the fluid rather than its acceleration. This is

the case throughout most of JIT 11 which was, for

the most part, a quasi-steady flow test.

Pipe

Branch Im

1I:.I, F..

CIJ,

IA

C

0

JL 0i

-PEI

W

'PI

W.

I . •* ,

I.". ..4.;'

/ ."*. .. t'"",

/" *1 ",:"

aL '." '' /

TJmdp jun

• o11

Figure 3-1

Schematic of RELAP5 model for JIT 11 level swell

simulations.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 12

1986-07-11

4. RESULTS AND DISCUSSION

For the level swell simulations a discharge mass

flow rate was imposed as a boundary condition.

The boundary condition was obtained by drawing

a smooth curve through the measured discharge

flow rate. The boundary condition is compared to

the measured flow rate in Figure 4-1. Figure 4-2,

which compares the computed pressure response to

the measured pressure response, demonstrates that

the boundary condition served its purpose.

4.1 Base case

For the base case simulation the vessel region

below the level of the standpipe was represented

by 20 nodes (AZ = 0.9 m). Differential pressures

were computed for comparison with measured differential pressures.

Figure 4-3 compares computed and measured dPs

over the top and bottom halves of the vessel.

The center tap for these measurements was initially located in the liquid but was uncovered

at the end of the experiment. The fairly good

agreement between the calculated and measured

dPs indicates that RELAP5 calculated the gross

behaviour of level swell correctly; that is, it

correctly calculated the mass of liquid which

was lifted above the 9.28 m elevation. It remains to be seen if the distribution of mass

above and below the 9.28 m elevation was computed correctly.

The fact that the RELAP5 calculated dP203 lies

below the measurement and the calculated dP205

lies slightly above the measurement during the

quasi-steady part (20-70 s) of the experiment
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 13

1986-07-11

indicates that RELAP5 lifted slightly more

liquid above the 9.28 m elevation than was actually transported there.

Besides dP203 one other valid measurement of differential pressure below the 9.28 m elevation was

obtained during JIT 11. It is shown together with

the corresponding RELAP5 value in Figure 4-4. The

fact that the computed dP lies above the measured

dP means that the average void fraction in the

region being spanned by the dP taps was higher in

RELAP5 than in the experiment (approximately 0.05

higher at 50 s).

The "overshoot" in the calculated dP in the

15-20 s time period is related to time step size.

The base calculation generally proceeded at the

maximum specified time step size (0.5 s). The

differential pressure histories at all locations

changed significantly in the 0-25 s range when

time step size was reduced (see section 4.3).

Differential pressure measurement 213 spanned

the initial liquid level surface (Figure 4-5).

The experimental dP response over this span

(9.23 to 11.43 m) showed that the average void

fraction initially decreased (0-3 s) as the liquid level swelled then increased (3-20 s) to a

value near the initial value as the two phase

mixture rose to its maximum elevation. The average void fraction remained fairly constant until

60 s when it began decreasing as liquid drained

into the region. When the outlet valve was completely closed (85 s) the average void fraction

increased rapidly to unity as all liquid drained

out of the region.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 14

1986-07-11

The RELAP5 simulation of dP213 behaved qualitatively the same as the measurement. However, RELAP5

calculated the average void fraction in the 9.23 m

to 11.43 m region to be lower than it was in the

experiment. The 2 kPa difference in dP between the

measurement and the calculation corresponds to a

voidX'raction difference of about 0.13 between

the experiment and the calculation (- 0.60 in the

experiment versus - 0.47 in the calculation).

When the outlet valve began closing at 75 s the

RELAPS calculation responded immediately - the dP

decreased, indicating that liquid was draining

into the region from above. The experiment

showed no such behaviour. The calculated dP began

increasing at 82 s, before the valve was fully

closed (84 s), and before the experimental dP

began increasing. By 90 s the experimental dP had

risen nearly to its maximum value (no liquid in

the region) whereas the calculation showed a significant amount of liquid remained in the region.

The inability of RELAP5 to mimic the experiment

during the 5-20 s time period and the 85-90 s

time period is attributed to the nature of the

interfacial friction model in RELAP5. For the

geometry and mass fluxes under consideration

RELAP5 assumes that bubbly flow exists for void

fractions less than 0.25 and slug flow exists

for void fractions between 0.25 to 0.95. The

interfacial friction associated with bubbly flow

is much larger than that associated with slug flow.

In the early (t < 20 s) part of the transient

RELAP5 was unable to lift enough liquid out of

the 9.23 - 11.43 region because the drag between

the vapor and liquid diminished too quickly as

the void fraction increased. Near the end of the

transient RELAP5 was unable to let liquid drain

out of the region as fast as it really did because
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 15

1986-07-11

of an increasing drag between the rising vapor and

falling liquid as the local void fraction dropped

below 0.25. In the experiment it is quite likely

that, once the valve was closed, the flow regime

in the 9.23 - 11.43 region switched from slug flow

to annular flow (the liquid draining downward along

the vessel a stc 1pipe surfaces) - a flow regime

change which cannot be simulated in RELAP5 with

the current flow regime maps.

The measured dP response over the 11.47 m to

13.46 m range (Figure 4-6) shows the same qualitative response as seen at the 9.23 to 11.43 m

range. A rapid decrease in differential pressure

occurred as liquid entered the region followed

by an increase as the local void fraction increased. The dP, and hence the average void fraction, in the region remained relatively constant

between 20 and 75 seconds. The dP increased

sharply as the valve was closed and liquid

drained out of the region.

RELAP5 calculated the dP response in the

9.23 - 11.43 range qualitatively correctly. However, it calculated too low a void fraction in

the region during most of the transient. Unlike

the calculated dP213 (Figure 4-5), the calculated

dP212 showed the same response as the measured

dP212 when the valve was closed. This is because

the local void fraction in the computational

cells which spanned the region never dropped

below a value of 0.25 as they drained.

Differential pressure dP211 (Figure 4-7) spanned

the 13.46 m to 15.45 m elevation. The accuracy of

this measurement is questionable because it did
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 16

1986-07-11

not return to the correct final value at the end

of the experiment - it was low by 4 kPa. The instruments response does appear to be correct at

10 s, because it indicates a dP value slightly

less than that of dP210, which lies above it.

This is reasonable, assuming a linear increase

in void fraction with elevation. It is also

likely that the instrument's response in the

10 - 50 s range is reasonably good because it

remains fairly constant, exhibiting a behaviour

similar to dP212 and dP213. If one assumes that

the two phase level in the experiment declined

steadily then dP211 should have remained constant

until 50 s and then should have increased at the

same rate as dP210 above it. In fact, the instrument shows this response which suggests that the

instruments response is correct over the 0-80 s

temperature range.

The uppermost dP measurement, dP210, spanned the

15.45 m to 17.45 m elevation. The response of

dP210 (Figure 4-8) shows that a two phase mixture

passed the 15.45 elevation at about 10 seconds,

reached its maximum level at 15 s, and slowly

subsided over the next 30 seconds. Measurements

of the discharge flow rate indicated that a small

amount of liquid entered the standpipe during the

17 to 25 s time period. From this one concludes

that the maximum elevation reached by the twophase level was about 18 m.

RELAPS calculated the dP210 response to decline

less than it actually did and to rise more

rapidly. RELAP5 carried somewhat less liquid into

the region spanned by dP210 than did the experiment. RELAP5 also calculated that the liquid

drained from the region much faster than it actu-
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 17

1986-07-11

ally did. This faster drainage manifests itself

in the different slopes of the measured and calculated dPs after 20 s.

Time step studies conducted subsequent to the

base calculation have shown that when smaller

time steps were used the RELAP5 clcr ated history of dP210 dipped briefly to a value of about

-1.0 kPa then recovered to zero. Thus the calculated history shown in Figure 4-8 is an unconverged one.

The RELAP5 simulation of the level swell, which

occurred in experiment JIT 11, can be summarized

as follows:

RELAP5 calculated that somewhat more liquid was

lifted above the initial liquid level than actually was (Figure 4-3, 4-4). Even though RELAP5

carried more liquid above the initial liquid

level, it did not calculate the two-phase level

to rise and remain as high as it did in the experiments (Figure 4-8, 4-7).

For the quasi-steady part of the experiment

(30 - 50 s) RELAP5 calculated the liquid fraction profile in the swelled region (the region

above the original water level) to be more concentrated in the lower elevations than it actually was (Figure 4-5 and 4-6). The latter observation is a recognition of the fact that the

RELAP5 overprediction of void fraction in the

4.97 to 9.23 m range (Figure 4-4) is more than

offset by the underprediction of the void fraction in the 9.23 to 13.43 m range (Figures 4-5,

4-6.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 18

1986-07-11

4.2 Nodalization studies

In order to determine the sensitivity of computed

results to nodalization the RELAP5 calculation of

JIT 11 was repeated using 40 and 100 nodes to

represent the 18 m long annular region from the

vessel bottom to the top of the standpipe. Some

results from the 20, 40, and 100 node cases are

given in Figures 4-9 through 4-12.

The most significant feature in Figures 4-9

through 4-12 is the erratic nature of the 100

node calculation. Other notable features are the

reduction, with increasing nodes, in the dP

"overshoot" in the lower elevations (Figure 4-9,

4-10; 15 < t < 25 s), and the decreasing calculated height of the two-phase level with increasing number of nodes (Figure 4-12). Figures 4-9

to 4-12 show that the RELAP5 calculation is sensitive to nodalization and does not converge with

increasing nodalization.

The reason for the erratic calculated dPs in the

100 node calculation is revealed in Figure 4-13,

which shows the void fraction profile in the

vessel at 42.5 and 43.5 seconds. For the region

spanned by dP212 (11.47 to 13.46 m) the average

void fraction changes from a value of 0.49 at

42.5 s to a value of 0.64 at 43.5 s. The calculated change in dP use to this change in void

fraction is (AdP = Aapfg Az) 2.3 kPa which is

about the change in dP shown in Figure 4-10. The

erratic nature of the results from the 100 node

calculation are due to RELAP5 calculating a

fluctuating axial void profile (for elevations

between 9 and 15'm) rather than the quasi-steady

void profile indicated by the experimental

measurements and by the 40 and 20 node RELAP5

calculations.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 19

1986-07-11

4.3 Time step studies

The 100 node calculation was examined further by

restarting it at 40 s and reducing the maximum

time step from 0.1 s to 0.05 s (the material

Courant limit was 0.12 s). The axial void profile

from these two calculations are shown in

Figure 4-14. Local differences in void fraction

are large even though the average step size utilized for the two calculations (0.075 s and 0.05 s

for DTMAX = 0.1 and DTMAX = 0.05 respectively)

was much less than the Courant limit.

The sensitivity of the 100 node calculation to

time step size demonstrates the unreliability of

the mass error time step control algorithm - the

algorithm does not necessarily produce time step

sizes which lead to a convergent solution.

It is believed that the erratic solution and the

time step sensitivity exhibited to the 100 node

calculated are related to the strong coupling between void fraction and interfacial drag in the

20 - 40 percent void fraction range. Because of

the large flow areas and short lengths of the

cells in the 100 node simulation void fractions

were observed to sometimes change dramatically

from one time step to the next. As a consequence

the interfacial drag changed by as much as a

factor of 10 from one time step to the next.

Having seen the sensitivity of the 100 node calculations to time step size we decided to investigate the sensitivity of the base (20 node) calculation to time step size.

The original calculation proceeded at the specified maximum time step which was 0.5 s. For the
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 20

1986-07-11

two sensitivity studies the maximum step size was

set to 0.1 s and 0.05 s. The results of the sensitivity calculations are depicted, along with

the base case results in Figure 4-15 to 4-19.

The figures show that the RELAP5 base case solution was not converged during the first 30 seconds of the transient. Using large time steps,

although entirely consistent with the mass error

time step control algorithm, gave an artificial

increase in the amount of liquid being carried

upward.

It is believed that the sensitivity to time step

is caused by the relaxation algorithm being used

in the interphase drag model. The model calculates an interphase drag coefficient based upon

new time level hydraulic parameters and then, to

get a interphase drag coefficient for use in the

momentum equations, weights the new time level

value with the old time level value, giving

favor to the old value. The result of the scheme

is that the code "remembers" previous values of

the interphase drag for several time steps regardless of time step size. During a period of

rapidly changing interphase drag (bubble-to-slug

flow) the computed results therefore become sensitive to time step size.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

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21

9 MASS FLOW RATE MEASURED

0 NOZZLE STEAM MASS FLOW RATE (20 NODE MODEL)

34

Li

C,

4A

X.

0i 10 20 30 40

so TIME (S)

60 ?0 $0 90 i00

Figure 4-1

Mass flow rate boundary condition and experimental discharge flow rate.

[9 001MI01 23.13 M ELEVATION (AVERAGED 20 1)

0 PRESSURE IN THE STEAM DOME (20 NODE MODEL)

40 sotCa so $ 0

.0 S 20 30 40 $0 40 0 gO O o s0c

1i1E (S)

Figure 4-2

Measured and calculated pressure response for

JIT 11.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

22

0

+

001M203 23.13 M - 9.28 M ELEVATION (AVERAGEDIO0 1) ) 00IM205 9.28 M - BOTTOM ELEVATION (AVERAGEDIOO I) CALC. DIFFERENTIAL PRESSURE 203 (20 NODE MODEL) CALC. DIFFERENTIAL PRESSURE 205 (20 NODE MODEL)

a.

I.J

I.'

Bas

at

4.

~Lb0 

TIlME (S)

Figure 4-3

Comparison of computed and measured dP's over

the top and bottom halves of the vessel.

CD X4P5 MEASURED DIFFERENTIAL PRESSURE 214-215

C0 CALC. DIFFERENTIAL PRESSURE 214 PLUS 215 (20 NODE MODEL) I I I I I :, at

ZCL S

S

I

S.

a

F aY"L tv.

Figure 4-4

Measured and calculated dP over the 4.97 m to

9.73 m span.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

23

O9 213M MEASURED DIFFERENTIAL PRESSURE 213

D CALC. DIFFERENTIAL PRESSURE 213 (20 NODE

'I U

Ld

or

-4-LAI

.jiiI__'-7 -1

i -,

S

I

.3

4-

a

A• I 20 30 40 so

'IME IS)

to

Figure 4-5

Measured and calculated dP over the 9.23 to

11.43 m Span.

ED(D 212M MEASURED DIFFERENTIAL PRESSURE 212

CALC. DIFFERENTIAL PRESSURE 212 (20 NODE MODEL)

I,2

C-% Q4

" i - _. _ ' _ -i•: ' " "

00 00f

I

'1* *8 _

U

4

II

a

S

I

SE

6

-I.

g.-'~~ SA.~

to 20 40

TIME IS)

go to to so too

Figure 4-6

Measured and calculated dP over the 11.47 to

13.43 m range.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

24

ID 211M MEASURED DIFFERENTIAL PRESSURE 211

C CALC. DIFFERENTIAL PRESSURE 211 (20 NODE MODEL)

°IT __ -- 

N

U

I -

'C

IL

S

S

I

.3

V

F Le"11.

tIME (S)

I

0

L..

Figure 4-7

Measured and calculated dP over the 13.46 to

15.45 m range.

210M MEASURED DIFFERENTIAL PRESSURE 210

CALC. DIFFERENTIAL PRESSURE 210 (20 NODE MODEL)

,I[ l •I I _ I -' M (S) , r i -' I I" "• ' - : i I • 1

IC 00 00 40 30 10 70 80 80O 100

Figure 4-8

Measured and calculated dP over the 15.45 to

17.45 m span.

L u

8iI(

0 Sif A
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

25

0

0

A49

213M MEASURED DIFFERENTIAL PRESSURE 213

CALC. DIFFERENTIAL PRESSURE 213 (20 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 213 (40 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 213 (100 NODE MODEL)

z

I.'

I w

JA. R

-IT,

Vq

U

U *1

C -

I

10 20 49 so T IME (S) ?a to w too

-ID

Figure 4-9

Measured and calculated dPs over

11.43 m elevation.

the 9.23 to

212M MEASURED DIFFERENTIAL PRESSURE 212

CALC. DIFFERENTIAL PRESSURE 212 (20 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 212 (40 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 212 (100 NODE MODEL)

aU)

C - -

q- ~.

*1

U

S.

S -

.0 to 20 30

?IIME fS) go ra so so

Figure 4-10

Measured and calculated dPs over the 11.47 to

13.46 m elevation.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

26

D0

A

211M MEASURED DIFFERENTIAL PRESSURE 211

CALC. DIFFERENTIAL PRESSURE 211 (20 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 211 (40 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 211 (100 NODE MODEL)

Bw

o',

LS.-

0-f Lt

Figure 4-11

Measured and calculated dPs

15.45 m elevation.

over the 13.46 to 11

19

D

210M MEASURED DIFFERENTIAL PRESSURE 210

CALC. DIFFERENTIAL PRESSURE 210 (20 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 210 (40 NODE MODEL)

CALC. DIFFERENTIAL PRESSURE 210 (100 NODE MODEL)

Bor

6, 0

-4-- -4- - .. . _. 

LL /-

I 'l•&f

'S

U.-

(~~1~

~Ii

*5*

;-ltV--' Ia

III .aa.

I 10 20 40 30

tiflE tS2

G0 70 so to t00

Figure 4-12

Measured and calculated dPs over the 15.45 to

17.45 m elevation.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 27

1986-07-11

0 VOID FRACTION AT 42.5 S. i00 NODES 0 0 VOID FRACTION AT 43.5 S. 100 NODES 0D

0

LL

0

0:I

ELEVATION (M)

Figure 4-13

Axial void profile for the 100 node simulation.

0 VOID FRACTION AT 43.0 S. 100 NODES

CD VOID FRACTION AT 43.0 S. 300 NODES.SMALL STEPS

z

0

C)

LL

0

0

0

Le)

o6 8 I 14d I4 10

ELEVATION (M)

Axial void profile for the 100 node simulation.

DTMAX = 0.1 s and DTMAX = 0.05 s.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 28

ED

0D

1986-07-11

X4P5 MEASURED DIFFERENTIAL PRESSURE 214-215

CALC. DIFFERENTIAL PRESSURE 214 PLUS 215 (20 NODE MODEL)

CALC DP214-DP215. 20 NODE MODEL DT=O.1O

CALC DP214'DP215. 20 NODE MODEL DT=O.05

N

U

a -

a

j I.

e.61 w

Sensitivity of dP214 + dP215 to time step size.

M

D

213M MEASURED DIFFERENTIAL PRESSURE 213

CALC. DIFFERENTIAL PRESSURE 213 (20 NODE MODEL)

CALC DP213. 20 NODE MODEL DTO.10

CALC DP213. 20 NODE MODEL DTO.05

Iw

|

I

4-

)I-* L 41

Sensitivity of dP213 to time step size.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

29

0

D

212M MEASURED DIFFERENTIAL PRESSURE 212

CALC. DIFFERENTIAL PRESSURE 212 (20 NODE MODEL)

CALC DP212. 20 NODE MODEL DT-O.10

CALC DP212. 20 NODE MODEL DTO.05

0

L0:

W,

a

I

~'I

S.-"- tA~.

Figure 4-17

Sensitivity of dP212 to time step size.

D

(

ft

211M MEASURED DIFFERENTIAL PRESSURE 211

CALC. DIFFERENTIAL PRESSURE 211 (20 NODE MODEL)

CALC DP211. 20 NODE MODEL DTO.1O

CALC DP211. 20 NODE MODEL DT=O.05

tfl

U..

lU.

Figure 4-18

Sensitivity of dP211 to time step size.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 30

1986-07-11

* 210M MEASURED DIFFERENTIAL PRESSURE 210

0 CALC. DIFFERENTIAL PRESSURE 210 (20 NODE MODEL!

A CALC DP210. 20 NODE MODEL DT=O.1O

4 CALC DP210. 20 NODE MODEL DT=O.05

I=.J

IL

W.,

,a

'tilE (S)

Figure 4-19

Sensitivity of dP210 to time step size.
STUDSVIK ENERGITEKNIK AB

5.

STUDSVIK/NP-86/97

1986-07-11

31

COMPUTATIONAL EFFICIENCY

The computational efficiency of the RELAP5

simulations is summarized in Table 5-1. The CPU

times are for a CYBER 180-810 computer.

In general, the simulations used the maximum

time step size specified in the input. This time

step size was usually slightly smaller than the

material Courant limit.

Table 5-1

Run time statistics for JIT 11 simulations.

(ninety second transient)

Case DTMAX Actual CPU(s) CPU/VOL/DT

time steps

20 node 0.01 (t<0.5s) 257 220 0.04 0.50 (t>0.5s)

40 node 0.01 (t<0.5s) 437 602 0.03 0.25 (t>0.5s)

100 node 0.01 (t<0.5s) 1 135 3 786 0.03 0.10 (t>O.5s)
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 32

1986-07-11

6. CONCLUSIONS

Assessment of RELAP5 against the level swell

data obtained from JIT 11 led to the following

conclusions:

1. For the 9 to 13 m range RELAP5 calculated a quasi-steady void fraction which

was 0.10 to 0.15 lower than measurements

indicated.

2. For the 13 to 18 m range RELAP5 calculated a quasi-steady void fraction which

was too high. In the base case RELAP

calculated the maximum level of the two

phase front well but allowed liquid to

drain out of the upper region of the

vessel faster than it actually did.

3. Nodalization studies demonstrated that

the RELAP5 solution did not converge

with increasing number of nodes. The 20

node case and the 40 node case gave

similar results. The 100 node case, however, exhibited erratic fluctuations in

the axial void profile and was sensitive

to time step sizes. The behaviour of the

100 node case is believed to be caused

by the interphase drag model.

4. The computed results were sensitive to

time step size. Time step size had to be

reduced considerably below the value

allowed by the RELAP5 time step control

algorithm in order to obtain converged

results during the time when the level

was rising. The sensitivity is believed

to be caused by the relaxation algorithm

in the interphase drag model.

The JIT 11 simulations have shown that the RELAP5

interphase drag model allows the interphase drag

force to diminish too rapidly with increasing

void fraction for the case of level swell in

large vessels. It would, however, be premature

to recommend changes in the interphase drag model

based upon the results reported here so long as
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 33

1986-07-11

the model is intended to be used for a variety

of geometries (tubes, rod bundles, vessels). Refinements of the interphase drag model should

consider separating the treatment of level swell

in large vessels from the treatment of flow in

ducts.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 34

1986-07-11

7. REFERENCES

1. TRAC-PFl/MODl:

An Advanced Best-Estimate Computer

Program for Pressurized Water Reactor

Thermal-Hydraulic Analysis.

NUREG/CR-3858.

2. RANSOM, V et al

RELAP5/MOD2 Code Manual.

NUREG/CR-4312.

August 1985.

3. The Marviken Full Scale Jet Impingement

Tests.

Facility Description.

MXD-101.

February 1982.

4. The Marviken Full Scale Jet Impingement

Tests.

Test 11 Results.

MXD-211.

March 1982.
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 Appendix A.1 (8)

1986-07-11

APPENDIX A

RELAPS INPUT DECK

=RELAPS INPUT FOR JIT-11 LEVEL SWELL (CASE I. RUN 2) 4

* MARVIKEN JET IMPINGEMENT TEST (JIT) NO. H1

4 IS USED FOR A LEVEL SWELL CALCULATION WITH

RELAPS/MOD2/36.02 AS A PART OF THE ICAAP

AGREEMENT.

* STEADY STATE RUN TO GET INITIAL PRESSURES

4 COMPONENIS 902,952,903,gs3,AND TABLE 210 WILL BE DELETED

ON THE RESTART FOR TRANSIENT RUN.

100 NEW STOY-ST

101 RUN

105 10. 20.

4

201

4

END DTMIN DTPEO FLAGS r1INED

2'0.0 1.0-6 0.50 00003 I

MAJED RESTART

20 100

4 MINOR EDITS

--------------

301

302

303

304

305

306

307

308

309

311

312

313

314

315

316

317

318

319

CNTRLVAR

CNTRLVAR

CITT RL VAR

MFLOUJ

MFLOWJ

TEMPF

TEMPF

TEMPF

TEMPF

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

CNTRLVAR

313

101

210

200030000

9S1000000

100010000

100050000

100100000

1001500c0

403

40S

410

411

412

413

414

415

417

TRIPS

501 TIME 0 GT NULL 100. L

35
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 Appendix A.2 (8)

1986-07-11

601 501 AND 501 L

4

* COMPONENT 100

* REACTOR VESSEL BELOW TOP OF STANDPIPE

• LEVELS: 0. - 18.33

1000000 VESSLOW ANNULUS

• NV

1000001 20

* VOLAREA VOLNO

1000101 0. 20 4

4 LENGTH VOLNO

1000301 1.23 1

1000302 0.90 20

4 VOLUME VOLNO

1000401 9.22 1

1000402 15.20 2

1000403 17.78

1000404 18.194 20

* VANGLE VOLNO

1000601 90. 20

• WROUGH HYD-DIA VOLNO

1000801 0. 4. 20 4

* VOLFLGS VOLNO

1001001 00 20

• JUNFLGS JUNNO

1001101 01000 19

* COMPONENT 200

4 REACTOR VESSEL ABOVE TOP OF STANOPIPE, BELOW SPRAY SHIELD

• LEVELS: 18.33 - 18.83

2000000 VESSMID BRANCH

* NJ

2000001 3

* VOLAREA LENGTH VOLUME AZI INCL ELEV ROUGH DIA FLGS

2000101 0. 0.50 10.79 0. 90. 0.50 0. 0. c0

* FROM TO JUNAREA LOSSF LOSER FLGS

2001101 100010000 200000000 0. 0. 0. 01100

2002101 200010000 300000000 19.6 0. 0. 01100

2003101 200000000 400010000 0. 0. 0. 01100
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97 Appendix A.3 (8)

1986-07-11

COMPONENT 300

* REACTOR VESSEL ABOVE SPRAY SHIELD

* LEVELS: 18.83 - 24.E18

3000000 VESSLOW ANNULUS

* NV

3000001 3

* VOLAREA VOLNO

3000101 0. 3 *

* LENGTH VOLNO

3000301 1.300 1

3000302 1.334 2

3000303 3.154 3

* VOLUME VOLNO

3000401 26.52 1

3000402 14.19 2

3000403 6.26 3

• VANGLE VOLNO

3000601 90. 3

* WROUGH HYD-DIA VOLNO

3000801 0. 5. 3

• VOLFLGc- VOLNO

3001001 00

* JUNFLGS JUNNO

3001101 01000 2

* COMPONENT 400

• STANDPIPE

• LEVELS: 0. - 18.33

4000000 STNDPIPE PIPE

* NV

4000001 1

VOLAREA VOLNO

4000101 0.6210 1

* LENGTH VOLNO

4000301 18.33 1

• VOLUME VOLNO

4000401 0. 1

• VANGLE VOLNO

4000601 90. 1

• WROUGH HYD-DIA VOLNO

4000801 0. 5.

37
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Appendix A.4 (8)

* UJOLFLGS

4001001 00

VOLNO

I

* COMPONENT 901

4 ATMOSPHERE

9

9010000 ATMOSPH TilOPVO,:

VOLAREA

9010101 10.

LENGTH

1.

VOLUME AZI

10. 0.

INCL ELEV

90. 0.50

ROUGH DIA

0. 0.

FLGS

00

9

9010200

CW

2

* TIME

9.10201 0.

4

PRESS QUAL

O.IE6 1.

• CI 4 N(

9510000

4

951 0101

9510200

9510201

ss 10202

9510203

9510204

9510205

9510206

9510207

9510208

9510209

9510210

9510211

9510212

9510213

9510214

9510215

9510216

9510217

9510218

9510219

9510220

9510221

9510222

9610223

9510224

9510225

9510226

OMPONENT 951

OZZLE FLOW AS

NOZZLE

FUNCTION OF TIME

TMDPJUN

FROM TO JUNAREA

400000000 0100000 0.

cW

1 601

TIME

0.

0.04

0.06

0.0B

0.10

0.16

0.20

0.24

0.28

0.32

0.40

0.46

0.52

0.60

0.70

0.80

I.

1.5

2.5

5.

7.

9.

16.

32.

50.

75.

LIOFLOW

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

O0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

VAPFLOW

0.

624.

632.

208.

647.

125.

139.

349.

432.

470.

432.

389.

393.

411.

415.

403.

392.

392.

401.

394.

390.

375.

336.

289.

228.

175.

ZEROL

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

38
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Appendix A.5 (8)

9510227 78.

9S10228 84.

0.

0.

113.

0.

0.

*

4=5=5=5 n=C=== ===~-=5==-~===~-====== ==== =======~-==~-==t======w

4

100 1202

1001203

001204

1001205

1001206

1001207

1001208

100 12039

10012104 1001205

1001210

1001211

1001212

*

VOLUME INITIAL CONDITIONS

Cw

3

3

3

3

2

3

3

3

3

7

-J

P

5.OEG

G.0E6

5.0E6

5.0E6

5.056

5.OE6

5.0E6

5.0E6

5.0E6

5.0E6

5.0E

5.0E6

X (OR T)

533.0

533.4

533.8

534.2

534.6

535.0

535.4

535.8

536.2

53E.6

0.001

1.00

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

VOLNO

4

6

7

8

9

10

11

20

2000200 2

3001201

4001201

5.0E6 1.00

5.OEG 1.00

5.0E6 1.00

0. 0. 0.

0. 0. 0.

3

1

====================== =========== = == = -=-====

4 JUNCTION INITIAL CONDITIONS

- - - - - - - - - - - - - -

1001301

2001201

2002201

2003201

3801301

0.

0.

0.

0.

0.

0.

0.

0.

0.

0.

Is

0.

0.

0.

0.

4 = = = = = = CS = = = = = = = = = = = = = = C = = = = = = = = = = = = = = = = = = = C = = = ~ = Cr5 ~ = CC = = =

4

4

20510100

20510101

20510102

20510103

20510104

20510105

20510106

20510107

20510108

20510109

20510110

20510111

20510112

20510113

20510114

CONTROL VARIABLES

LIQLEV

0.

SUM

1 .23

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

0.90

1.0

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

0.

100010000

100020000

100030000

100040000

100050000

100060000

100070000

100080000

100090000

100100000

100110000

100120000

100130000

100140000

I

39
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Appendix A.6 (8)

20510115

20510116

20510117

20510118

20510119

20510120

20530100

0.90

0.90

0.90

0.90

0.90

0.90

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

VOIDF

100158000

100160000

100178000

100180000

100190000

100200000

LEVOI SUM

20530101 0. 1.57746 P

20530200 LEV02 SUM

20530201 0. .56056 P

20530300 LEV03 SUM

20530301 0. .50556 P

20530400 LEV04 SUM

20530401 0. .34778 P

20530500 LEVOS SUM

20530501 0. .19000 P

20530600 LEVO0 SUM

20530601 0. .60778 P

20530700 LEV07 SUM

20530701 0. .56111 P

20530800 LEVOS SUM

20530801 0. .16222 P

20530900 LEVO9 SUM

20530901 0. .12778 P

20531000 LEVIO SUM

20531001 0. .91556 P

20531100 LEVII SUm

20531101 0. .69556 P

20531200 LEV12 SUM

20531201 0. .47778 P

20531300 LEVI3 SUM

20531301 0. -. 03966 P

I1. 0.

100010000

1. 0.

100010000

1. 0.

100030000

I. 01.

100050000

1. 0.

100070@00

1. 0.

10010000

1. 0.

100100000

1. 0.

100120000

1. 0.

100120000

1. 0.

100150000

18017@000

100190000

3000208000

-. 57746

.43944

.49444

.65222

.81000

.39222

.4388 9

.83778

.67222

.08444

.30444

.52232

1.03966

100020080

100020000

100040000

100060000

100080000

100110000

100110000

100130080

100130000

100160000

100180000

100200000

300030000

* .000

* 1.083

4 3.025

* 4.957

* 6.909

* 9.233

• 9.275

• 11.434

4 11.465

* 13.456

*15.454

* 17.450

' 23.130

20540300

20540301

4

20540500

20540501

20541000

20541001

20541100

20541101

20541200

20541201

20541300

20541301

4

20541400

20541500

20541501

20S41700

20541701

DP203 SUM

10321. 1.

0P205 SUM

71051. 1.

0P210 SUM

497.1 1.

DP211 SUM

497.0 1.

0P212 SUM

495.0 1.

OP213 SUM

7727. 1.

0P214 SUM

17713. 1.

DP215 SUM

14870. 1.

0P217 SUM

14925. 1.

I. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

1. 0.

CNTRLVAR

313

307

1

312

1 311

1 310

308

306

305

1 7310

-I. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

-1. CNTRLVAR

307

301

311

310

309

306

305

304

302

40
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Appendix A.7 (8)

4

20549900 DF214+215 SUM 1. C.

20549901 0. 1. CNTRLVAR 414

1

1 . CNTRL'JAR 415

4=========== ==- = ::::::::::::::= = - === = =

* STEADY STATE CARDS

- - - - - - - - - -

* COMPONENT 902

• STEADY STATE PRESSURIZER

9020000 PRZ

• VOLAREA

9020101 10.

TMDPVOL

LENGTH VOLUME AZI INCL ELEV ROUGH DIA FLGS

1. 10. 0. 90. 1. 0. 0. 00

9020200

cW

2

4 TIME

9020201 0.

PRESS

5.OEE

QUAL

I.

4

9

COMPONENT 952

STEADY STATE CONNECTION TO THE PRESSURIZER

9520000 PRZLIN

* FROM

9520101 300010000

9520201 0

• COMPONENT 903

SNGLJUN

TO JUNAREA

902000000 0.

LOSF

0.

LOSSR

0.

FL G

01100J

0. 0. 0.

4 STEADY STATE LIOUID FILL VOLUME

9030000 FILL

4 VOLAREA

9030101 10.

TMOPVOL

LENGTH VOLUME AZI INCL ELEV ROUGH DIA FLGS

1. 10. 0. 90. 1. 0. 0. 00

4

9030200

4

CW

3

TIME

9030201 0.

COMPONENT 953

* STEADY STATE FILL

PRESS QUAL

5.OEB 533.

JUNCTION TO OBTAIN THE CORRECT WATER LEVEL

9530000 FILLJUN

• FROM

9530101 903000000

TMOPJUN

TO JUNAREA

100000000 0.

41
STUDSVIK ENERGITEKNIK AB STUDSVIK/NP-86/97

1986-07-11

Appendix A.8 (8)

S530200 1 0 CNJTPLVAR 210

9530201

9530202

9S30203

20521000

20521001

-10000.

-0.5 -O.S

0.5

LIQUID LEUEL

FILLFLOW

10.2

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0.

0.

0.

0.

0.

0. 0. 0.

10000. 0. 0.

CONTROL

SUM

-1I.

SY ST EM

20000. 0.

CNTRLVAR 101

I

42
MMC PORNU 31m US UCL2A% %tGUL&lO f m t

c 'g % I * ftO b t o,* hL*Ag IAAv-oj,, TIDC a w No. . )If

1HE BU A C D NUREG/IA-0006

=M . 3X2 BIBLIOGRAPHIC DATA SHEET STUDSVIK/NP-86/97

OWE IrftMUCTIsOeI 00, T4E AEIVImI

2 VITL, &NO SUITITLE 3 LALAI ZL&ff.

ICAP Assessment of RELAP5/MOD2 Against Marviken Jet

Impingment Test II Level Swell

a OATE REPORt CO'P,,ITE

S AITMORs, July 1 1986

S DAlE REPORT IS.jOED

0. Rosdahl, D. Caraher MoN" I I EAl

September 1986

T P•ERFORi•N)4G O•AIAIZATIOff NAME AND MAILING ADDEISS .+• e'eCai I a'..:T 1ASL "OnRR UNIT NPI.M1EM

Swedish Nuclear Power Inspectorate 9 IFL..,, GRAN, NUM,,E A

Box 27106

5-102 52 Stockholm, Sweden

10 SPONSORING ORGANIZATION NAME AND MAILING ADDRESS (u.,M Z. Coot 11, -'E OF REPOA1

Technical Report

Office of Nuclear Regulatory Research

U. S. Nuclear Regulatory Commission bz ZO COVERED .. ,

Washington, D. C. 20555

12 SUP.EMENTAPY NOTES

13 ABSTRACT (200 wooOs 0, ft

RELAP5/MOD2 simulations of level swell of saturated liquid in a large (5 m diameter,

22 m high) vessel are reported. For certain nodalizations RELAP5 is shown to predict

the measured void fraction profile with fair accuracy. RELAP5 results are shown to be

dependent upon nodalization with the accuracy of computed results deteriorating

significantly when a large number of nodes is employed.

I& DOC.JMIAT ANALYSIS - a KEY10ORDSMOESCRiPTORS 15 AVAIA8 0I1V

STATEMENT

RELAP5/MOD2, Marviken Jet Impingment Test, Level Swell, ICAP Code

Assessment

t IDENTIFIERS'OPE% ENDEZ TERVS

Unlimited

it SECURITYCLASSfFICAIO*%

rcnssif ied

ITA+,j *wot,r

Unclassified

17 NUMBE- OF PAGES

IE OR CE




UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

SPECIAL FOURTH-CLASS RATE POSTAGE & FEES PAID

USNRC

WASH. D.C. PERMIT No. G-67

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