Upload
dangquynh
View
223
Download
0
Embed Size (px)
Citation preview
AE-131
<
LLJ Measurements of Hydrodynamic Instabilities,
Flow Oscillations and Burnout in a Natural
Circulation Loop
K. M. Becker, R. P. Mathisen, O. Eklind
and B. Norman
AKTIEBOLAGET ATOMENERG
STOCKHOLM, SWEDEN 1964
AE-131
MEASUREMENTS OF HYDRQDYNAMIC INSTABILITIES, FLOW
OSCILLATIONS AND BURNOUT IN A NATURAL CIRCULATION
LOOP
Kurt M. Becker, R« P. Mathisen. O. Eklind and B. Norman
Summary:
The hydrodynamic stability and the burnout conditions for flow
of boiling water have been studied in a natural circvtlation loop in the
pressure range from 10 to 70 atg. The test section was a round, duct
of 20 mm inner diameter and 4890 mm heated length.
The experimental results showed that within the ranges tested
the stability of the flow increases with increasing pressure, increas-
ing throttling before the test section, but decreases with increasing
inlet sub-cooling and increasing throttling after the test section.
The measured thresholds of instability compared well with the
analytical results by Jahnberg.
For an inlet sub-cooling temperature of about 2 C the measur-
ed burnout steam qualities were low by a factor of about 1.3 compared
to forced circulation data obtained with the same test section. At
higher sub-cooling temperatures the discrepancy between forced and
natural circulation'data increased, so that at A*, •, = 16 C, the na-
tural circulation data were low by a factor of about 2.5.
However, by applying inlet throttling of the flow the burnot
values approached and finally coincided with the forced circulation
data. '
Printed and Distributed in January 1964.
LIST OF CONTENTS
1.0
2 . 0
2 . 1
2 . 2
3 . 0
4 . 0
5 . 0
6 . 0
6 .1
6 . 2
6 . 3
6.4
6.5
6.6
7 . 0
Introduction
Apparatus
Test Section and Power Supply
Ins tr umentation
Experimental Procedures
Research Program and Range of Variables
Results of Preliminary Runs Without SteamSeparator
Results with Steam Separator
Effect of Pressure
Effect of Inlet Sub-cooling
Effect of Liquid Level
Effect of Inlet Throttling
Effect of Outlet Throttling
Measurements with Simultaneous Inlet andOutlet Throttling
Comparison with Analytical Results
Nomenclature
BibliographyTableFigures
Page
i
5
6
68
9
11
12
12
14
15
15
16
37
a 7
19
20
2122
- 3 -
1.0 Introduction
During recent years a research program concerning the flow
of steam water mixUires in vertical heated channels has been in
progress at the Heat Engineering Laboratory of AB Atomenergi in
Sweden. During the first phases of this program the steady forced
circulation flow was studied, and measurements of pressure drop,
void fractions, heat transfer coefficients and burnout have been
presented in a series of reports ( l , 2, 3, 4, 5, 6).
However, in the channels of a nuclear boiling reactor natural
circulation flow is encountered. For this case the driving head is
the difference in density of the steam water mixture inside the
channel and the water in the moderator which also acts as a down-
comer. In a system like this it has been observed by many investi-
gators that the flow may become unstable and that heavy hydrody-
namic oscillations may under certain conditions start to develop.
These oscillations have a great effect on the burnout conditions for
the channel, so that burnout values obtained in a natural circulation
system may only be a fraction of those which one would predict on
the basis of steady state measurer ents. Furthermore the oscilla-
tions influence the void volume in the channels and therefore also
the reactivity of the reactor.
It is therefore of major importance for the designer of boiling
reactors to be able to nredict the onset of flow instabilities in the
fuel elements, and also the nature of the flow and the burnout con-
ditions during oscillatory behaviour of the system. During the last
few years the results of a large amount of work, both, theoretical
and experimental, have appeared in published works concerning
this problem. Despite this, present knowledge in the field is not
sufficient for safe and accurate predictions of the hydrodynamic
stability of the flow in boiling water reactor systems.
It was therefore decided to include in our two phase flow research
program a study of the flow in verv leal heated channels during natural.
- 4 -
circulation. The method of attacking the problem has been to simu-
late the reactor fuel element by means of a test section which
is electrically heated. It is desirable to carry out full-scale experi-
ments, but such experiments would be very time-consuming and
expensive. In addition, it would be difficult to interprete or analyze
in terms of the basic flow variables, the results obtained in full-
scale test sections consisting of a large number of rods.
We therefore found it quite suitable to start the investigation
by studying the flow in channels of the most simple geometry, such
as round ducts with the purpose of determining the influence on sta-
bility and burnout of such basic parameters as static pressure, in-
let subcooling, surface heat flux, mass velocity, test section dia-
meter, heated length and inlet and outlet throttling. However, it is
planned later on to continue the investigation in annuli and rod
clusters.
The application of the results obtained in a simple geometry
to the design of fuel elements in nuclear reactors is of course quite
problematical. However, simultaneously with the present experi-
mental study, a theoretical analysis of the problem has also been
conducted, and the analytical results will be reported separately
by Jahnberg (7). Because of the simple geometry the present ex-
perimental results may prove to be very useful for testing the
accuracy of the theoretical model, which later on may be applied
to reactor computations.
One should also note that another important physical differen-
ce exists between a loop experiment and the conditions encountered
in a reactor. When the flow oscillates in the reactor, the steam
void fraction and the reactivity of the system become time depen-
dent. The change of reactivity influences the power which again in-
fluences the void fraction. In a loop experiment the above-mention-
ed coupling between void fraction and power is not present, nor is
the coupling between different channeLS.
- 5 -
The present report deals mainly with the measurements ob-
tained with a 20 mm inside diameter test section of 4980 mm heat-
ed length. Some preliminary measurements obtained with a 10 mm
inside diameter duct of the same length, and in a somewhat different
loop are also included.
2. 0 Apparatus
The flowsheet of the loop is shown in figure 1 and in figure 2
a photograph of the upper part of the apparatus is reproduced.
From the 4890 mm long electrically resistance heated test
section of 20 mm inner diameter the fluid flows through a riser of
36 mm inside diameter and into a steam separator. The details of
the separator are shown in figure 3. The steam water mixture was
discharged radially into the separator through 96 holes in the riser.
The diameter of the holes was 8. 2 mm. From the top of the steam
separator the steam flowed to an aircooled condenser, with a capa-
city of 300 kW, a.nd the condensate returned to the bottom of the
steam separator where it mixed w _th the rest of the water. From
the separator the water flowed through a 51 mm inner diameter
downcomer, passed a preheater and a cooler for adjusting the in-
let temperature, before returning to the inlet of the test section.
The downcomer was also supplied with a throttle valve and between
the preheater and the test section a venturimeter was mounted for
measuring the flow rate.
The loop was designed for an operating pressure of 65 atg
and constructed of stainless steel.
For further details of the loop and its exact dimensions we
refer to a previous report (&).
Initially the loop was constructed without a steam separator
in accordance with the flowsheet i i figure 4. Some measurements
- 6 -
obtained with the loop without separator are also included in the
present report.
2.1 Test section_andjDowe£ jsupply
The test section consisted of a 20 mm inner diameter stain-
less steel duct of 4980 mm heated length. Three copper cylinders,
32 mm outside diameter and 25 mm long were brazed on the test
section at three points, one in the center and one at each end. The
copper electrodes, supplying the power to the test section, were
clamped round the copper cylinders. The power was supplied from
a direct current generator. The maximum available current was
6000 amps, and voltages ranging from 0 to 140 volts could be ob-
tained. The two end electrodes were connected to one pole of the
generator, and the central electrode to the other pole. This arrange-
ment made it unnecessary to insulate the test section from the rest
of the loop in order to prevent loss of electric power to the other
parts of the loop.
The pressure taps, consisting of 4 mm inner diameter stain-
less steel tubes, were welded round \,. 0 mm diameter holes on the
test section, just below the lower electrode and just above the upper
electrode.
2,2 Instrumentation
The following quantities were measured.
1. Static pressure
2. Pressure drop over test section
3. Inlet and outlet water temperatures
4. Power input
5. .Mass fliow rate - .
6. Liquid level in the steam separator
7. Wall temperatures at 16 axial positions of the test section
8. Pressure drop over the throttle valve
— i —
The static pressure in the loop was measured with a precision
calibrated manometer connected to the inlet of the test section.
The pressure drops over the test section and the throttle
valve were obtained by means of D.P. cells.
The fluid temperature measurements were accomplished by-
means of copper constantan thermocouples mounted in wells
100 mm deep and with a 3 mm inside diameter. A precision
Cambridge potentiometer was used for measuring the voltages.
The wall temperatures were also measured by means of copper
constantan thermocouples connected to the potentiometer.
The liquid level in the steam separator was measured by
means of a D.P. cell, and is in the present report given as the
height above the lower electrode, where the heating of the test
section starts.
The power was obtained by measuring the voltage over and
the current through the test section. The voltage was measured with
a Goerz precision voltmeter of 4/4 per cent rated accuracy, and
the current was obtained by measuring the voltage over a calibrated
shunt. For the latter measurement a millivoltmeter with a rated
accuracy of l/4 per cent was used.
The mass velocity was measured with a calibrated venturi-
meter. The venturimeter pressure drop was obtained with a D.P.
cell. The accuracy of the flow measurement is estimfe-ted at 2 per
cent.
The flow oscillations were observed by studying the time
variations of the mass velocity. The output of the D.P. cell was
coupled to an oscillograph where traces of the oscillations were
obtained. Observations of the oscillations were also possible by
studying the pressure drop över the test section.
Further, two burnout detectors were installed in order to
prevent the test section from being damaged by overheating when
burnout conditions were reached.
3.0 Experimental Procedures
Before starting ä run the loop was completely filled with de-
salinated water, and all ducts connecting instruments to the loop
were degassed.
* Then a small amount of power was supplied to the test
section. As the temperature of the water increased, the surplus
water due to thermal expansion was discharged from the loop
through a cooler and to the laboratory drain, so that the desired
operating pressure was obtained. The power to the test section was
slowly increased, and as steam started to be generated the dis-
charge rate from the loop increased and a water surface in the
loop was formed. This procedure continued until the water surface
had reached the desired level in the steam separator. Then the
first readings of the instruments were taken. After noting the ob-
servations the power was slightly increased, the liquid level adjust-
ed by discharging more fluid and after about 15 minutes thermal
equilibrium was obtained so that a new set of readings could be tak-
en. This procedure continued until the burnout detector shut off the
power, indicating that burnout conditions had been reached in the
test section
As the power increased and the void fraction in the test sec-
tion and the riser increased, the driving head, which is equal to the
difference in weight between the fluid in the downcorner ana the test
section-including the riser, also increased. This caused the flow
rate to increase. However, one generally reached a point where the
additional driving head due to increased power was not sufficient-to
compensate for the increased friction aid acceleration pressure
drops in the test section. Then the mass flow rate started to de-
- 9 -
crease when the power was further increased. Ultimately the pow-
er reached a value where the flow became unstable and started to
oscillate. Three cases are actually possible.
I* Diverging oscillations causir-? burnout
2. Stable oscillations
3. Burnout without oscillations.
For the second case, the amplitude of the oscillations in-
creases, if one continues to increase the power, and burnout will
finally be obtained.
For the third case the flow is completely stable until burnout
is obtained, and one would expect the burnout values to be identical
with values obtained during steady state forced circulation.
During the present study all three cases have been encountered.
4. 0 Research Program and Ran g e of Variables
The main part of the present, report deals with measurements
obtained with a 20 mm inner diameter test section of 4980 mm heat-
ed length. An examination of the problem revealed that for a fixed
geometry of the loop and the test section the following parameters
may influence the threshold of instability.
1. System pressure
2. Inlet sub-cooling
3. Liquid level in the steam separator.
The critical power may therefore be defined by the func-
tion.
=f(p, £s tgub , H) (1)
The mass velocity, m/F, and the steam quality x are not
included since thes t parameters a~>; determined when the parame-
ters in eq. 1 are fixed. In addition to the parameters in equation 1
- 10 -
it was decided also to study the effects of changing the geometry of
the loop. The geometrical changes employed were throttling of the
flow before or after the test section.
The performance of the loop permitted the static pressure to
be varied between 10 and 70 atg, the inlet sub-cooling between 2
and 16 C and the liquid level between 563 5 and 593 5 mm above
the reference level.
Throttling of the flow before the test section was achieved by
means of the throttle valve in the downcomer: 5 positions of this
valve were employed.
Throttling of the flow after the test section was obtained by
reducing the number of 8 mm holes in the riser exit. 2, 3, 4 and
96 holes were used. In addition, a few runs were made with both
inlet and outlet throttling.
In order to reduce the number of runs, the effect of inlet sub-
cooling, liquid level and throttling were only studied at a pressure
of 50 atg. The total research program consisted then of 30 runs.
Some preliminary runs obtained before the steam separator
was installed are also included in the present report. These runs
comprised measurements with a section of 10 mm inner diameter
of 4980 mm heated length.
For the runs without steam separator it was difficult to keep
the water level constant during a complete test. As the power was
increased and more cooling capacity was required, the liquid level
in the cooler moved downwards. Further it was very difficult to
operate at low sub-cooling temperatures, so that the measurements
were performed in the sub-cooling temperature range from about
80 to 250 °C.
- 11 -
5. 0 Results of Preliminary Runs Without Steam Separator
In figures 5 and 6 the measured mass velocities are plotted
versus the surface heat flux. The figures cover data between 10
and 60 atg obtained with a 10 mm tube, and the inlet temperatures
were 20 and 100 C respectively for the two sets of data given in
the figures. One should note that the inlet temperature and not the
inlet sub-cooling is constant so that the sub-cooling varies with the
pressure.
The end point on each curve represents the last measurement
of the series. A further increase of the power caused the burnout
detector to react, indicating that burnout conditions had been ob-
tained in the test section. For all the runs shown in figures 5 and
6 the flow was stable until the last power increase. Then diverging
oscillations with a frequency of about l /4 sec" developed and
after a period varying between 10 and 45 seconds the burnout de-
tector reacted. The oscillations were observed as fluctuations on
the mass flow rate, the inlet temperature and the test section
pressure drop measurements.
The figures reveal that the stability of the loop increases with
the pressure. Concerning the effect of inlet sub-cooling a compa-
rison of the data in figures 5 and 6 indicate that the critical power
increases as the inlet sub-cooling increases. This, however,
should not lead to any general conclusion that the stability of the
flow increases as the inlet sub-cooling increases. One should note
that in the present case where the inlet temperatures for the two
"sets of data are 20 and 100 C respectively, a substantial part of
the power is used for heating the water up to the saturation temp-
erature. A more correct measure of the effect of inlet sub-cooling
on the stability is obtained by considering the exit steam qualities
which are plotted in figure 7 versus the static pressure. One ob- .
serves that the exit steam quality at the onset of ixwtability increas-
es with both the pressure and the inlet temperature, indicating that
the flow becomes more stable at higher pressures and at lower in-
- 12 -
let sub-coolings. Actually, one might expect the flow to become
completely stable when the pressure approaches the critical pressu-
re since no flow oscillations of the kind studied in the present work
can exist at the critical pressure.
6. 0 Results with Steam Separator
The main and most important part of the present study dealt
with measurements obtained when the steam separator was mount-
ed in the1 loop. The performance of the loop was now much better,
compared with the earlier case, as it was easier to control the
pressure and the inlet temperature, and the data obtained under
these conditions were therefore more accurate and possessed an
excellent reproducibility.
The effects of pressure, inlet sub-cooling, liquid level, in-
let throttling and outlet throttling were studied separately. In the
following paragraphs the measurements dealing with each of these
variables will be discussed.
6.1 Effect of pressure
The effect of pressure was studied for the case where the in-
let sub-cooling was approximately 2 C, and where the liquid sur-
face was 5835 mm above the reference level. The reults are shown
in figure 8, where the measured mass velocities are plotted versus
the surface heat flux. The power density,or the power per litre test
section, is also indicated along the horizontal axis, since perhaps
this parameter is of greater significance for the stability than the
surface heat flux. Curves representing the threshold of instability
and the burnout values are also given. Concerning the measurement
of mass velocity after the onset of instability, there may be slight
errors in the measured values, due to the effects of fluid accellera-
tion on the venturimeter readings. Only dotted curves are therefore
shown in the oscillating flow regime.
13 -
One observes that as the pressure increases the threshold
of instability increases and approaches the burnout curve with
which it coincides at approximately 65 atg. For higher pressures
burnout is obtained directly without the,,flow passing through the
oscillating regime.
The flow oscillations were studied by recording the output from
the venturimeter and its D.P. cell. Figures 9 and 10 show traces
obtained at different pressures just before burnout. Although the
absolute values may possess serious errors, the figures show
that as the pressure increases the amplitude of the oscillations
becomes smaller, indicating less violent oscillations and more
stable flow.
Figure 11 shows the frequencies of the oscillations discuss-
ed in the previous diagrams. A slight increase in frequency from
0. 55 sec t(
10 to 50 atg.
-1 -10. 55 sec to 0. 62 sec is found as the pressure increases from
Figure 12 shows traces of mass velocity oscillations obtain-
ed at a pressure of 20 atg. As the heat flux increases and burnout
conditions are approached, the amplitude of the oscillations in-
creases while the frequency remains almost constant.
Reverting to figure 8, one observes that the burnout heat flux
has a maximum value at a pressure of 65 atg. This is in agreement
with the available information for steady state forced convection
burnout where the maximum heat flux occurs at a pressure between
40 and 7 5 atg (9).
In order to compare the measured burnout values with forced cir-
culation burnout conditions, the test section was, on completion of
the measurements, mounted in a forced circulation loop. This loop
had a pump with a pressure head of 8 atg. It was therefore possible
to apply heavy throttling of the flow before the test section, securing
- 14 -
stable operation of the loop. Unfortunately the forced circulation
loop had only a maximum operating pressure of 40 atg, so that the
comparison could only be established up to this pressure»
The comparison in question is given in figure 13 in terms of
the burnout steam qualities and the data are summarized in table
I on page 21. One should note that the forced circulation data were
obtained by extrapolating from the measurements to the same heat
fluxes as the natural circulation data. The comparison reveals that
the forced circulation data are higher by a factor of about 1.3 . This
seems to be the case even at the highest pressures where no flow
oscillations were observed. No satisfactory explanation has been
found for this discrepancy.
However, this could be attributed to the fact that the ampli-
fication of the signals from the flow measuring device has not been
adequate to indicate minor oscillations in the natural circulation
flow at high pressures.
6. 2 Effect of Inlet Sub-cooling
The effect of inlet sub-cooling was studied at a pressure of 50
atg and a liquid level, H, of 5835 mm in the steam separator. The
mass velocity versus heat flux curves are given in figure 14, and in
figure 15 the heat fluxes at the onset of oscillations and at burnout
are plotted versus the inlet sub-cooling. It is observed that the sta-
bility of the flow is strongly reduced as the inlet sub-cooling in-
creases. At 16 °C inlet'sub-cooling a critical heat flux of 24 W/cm
was obtained compared with 73 W/cm at 2 C sub-cooling.
However, at very large sub-cooling temperatures it is possible,
as discussed in section 5. 0, that the critical power will start to in-
crease with a further increase of the inlet sub-cooling, since a re-
latively large portion of the power is then used for just heating the
water up to the saturation temperature. This behaviour is demonstrat-
- 1 5 -•
ed in figure 16, where the critical power density at a pressure of
50 atg is plotted versus the inlet sub-cooling. In the figure are al-
so included the data obtained at 164 C and 244 C inlet sub-cooling
with the 10 mm diameter test section before the steam separator
was installed. A very large increase of the critical power density
is observed at the highest sub-coolings, so that the valu^ obtained
at 244 C inlet sub-cooling, is actually higher than the value
corresponding to 2 C sub-cooling.
Our loop is now being modified with the purpose of being
able to study the flow in the whole range of sub-cooling tempera-
tures.
6 . 3
The effect of the liquid level in the steam, separator was
studied for the case of 2. 0 °C inlet sub-cooling and 50 atg pressu-
re. The maximum possible variation was 3 00 mm, and since this
value is small compared with the length of the test section with
the riser, only small variations of the measured critical and burn-
out heat fluxes may be expected. The conclusions reached should
therefore be treated with caution.
The measured mass velocities versus surfase heat flux are
shown in figure 17. One observes that the burnout heat flux increas-
es slightly with increasing liquid level, while the critical heat flux
remains constant. The corresponding steam qualities, however,
which are indicated in figure 18, decrease with increasing liquid
level, suggesting that the loop stability decreases.with increasing
liquid level.
lnlelThe effect of throttling before the. test section was studied for
the cases of 50 atg pressure, 583 5 mm liquid level and — 2, 0 C
and ~ 11,0 C respectively inlet sub-cooling. The measured mass
- 16 -
velocities are given in figures 19 and 20. The throttling of the flow
through the throttle valve is indicated by means of the | j-values de-
fined by the equation
where v is the velocity of saturated water through the test section.
One observes that as the throttling increases, the stability of
the loop also increases and one reaches a point where the flow is so
stable that burnout is obtained directly without preceding flow
oscillations. With regard to the burnout heat fluxes, these also in-
crease with increasing inlet throttling until they reach a maximum
whereafter they decrease with further throttling due to the high
steam qualities which are now encountered in the test section»
This is more clearly demonstrated in figure 21, where the
burnout steam qualities are plotted versus the inlet throttling. The
corresponding values for forced circulation are also indicated in
the figure. The forced circulation points were obtained by extra-
polation to 50 atg fromthe measured values, which were obtained
between 10 and 40 atg. As the pressure drop over the throttle valve
increases, the measured burnout steam qualities rapidly approach
the values for forced circulation, indicating the absence of flow
instabilities.
k'- - JFIf Lcl °A.P^I0! Throttling
The outlet throttling was varied by changing the number of 8
mm holes at the end of the riser. For all the measurements in the
previous paragraphs 96 hole's were used corresponding to a value
of 16.15 of the ratio F /F , where F is the cross sectional area
of the test section and F is the area of the riser outlet. The flowo
was throttled by reducing the number of holes to 2, 3 and 4 corre-
sponding to area ratios of 0.328, 0.492 and 0.656. For these runso
the pressure was fixed at 50 atg, the inlet sub-cooling at « 2 C andthe liquid level at 583 5 mm.
- 17 -
The results arc shown in figure 22. As the outlet throttling of the
flow increases, the critical and the burnout heat fluxes decrease
sharply, indicating that outlet throttling renders the flow more
unstable. The burnout steam qualities, which are also indicated,
first approach the forced circulation value of 0. 80, but the value
for the highest throttling is only 0.48. No satisfactory explanation
has been found for this fact.
6. 6Measurement^ ^i£h ^ m u - l t a ^ o u s Inlet
Finally one test series was obtained using a riser with three
8 mm holes and varying the inlet throttling. This test series was
performed at a pressure of 50 atg, 2 C inlet sub-cooling and a
liquid level of 583 5 mm. The results are shown in figure 23. One
observes that the burnout heat flux first increases, reaches a maxi-
mum value and thereafter decreases with the inlet throttling. Further,
it is seen that the flow becomes more stable as the inlet throttling in-
creases and reaches a condition where burnout is obtained directly
without preceding flow oscillations.
The burnout steam qualities for the runs in figure 23 varied
between 0. 82 and 0. 93, which is well above the forced circulation
value of 0. 80. This inconsistency is probably due to an error in the
mass flow rate measurements at burno\it.
7.0 Comparison with Analytical Results
Simultaneously with the measurements described in the present
report, an analytical study of the problem was undertaken by Jahnberg
(7) with the aim of developing a model which later could be used for
predictions of reactor stability. The first phase of that study consist-
ed of developing a model describing the flow during steady state. Du-
ring the second phase small perturbations were added to the steady
flow, and a model for predicting when the perturbations would grow
or decay was established. The details of the analysis are given in
the reference mentioned above.
Figures 24 and 25 show a comparison between the predict-
ed and the measured mass velocities for the case of 2 C inlet sub-
cooling and no throttling. In the pressure range from 20 to 50 atg
the agreement between 'theoretical and measured mass velocities is
rather good, the discrepancy being a maximum of 10 per cent and on
the average only 3 - 4 per cent. For 10 atg the theoretical values
are about 15 per cent higher than those measured, but at 7 0 atg the
theoretical are about 15 per cent lower. The measured and the pre-
dicted thresholds of instability are also indicated in the figure. One
should note that for the case of 70 atg burnout was obtained without
observing any oscillations. In this case the analysis predicts stable
flow up to a steam quality of 1.0.
The thresholds of instability are more clearly demonstrated
in figure 25, where the surface heat fluxes at the onset of oscillations
are plotted versus the pressure. The measured values compare
excellently with the predictions, the difference between the two sets
of values being always less than 10 r>er cent.
The data obtained at 50 atg inlet sub-cooling temperatures of
7, 11 and 16 C were also analyzed by Jahnberg. Figure 26 shows
the predicted and the measured stability limits. The agreement
between experimental and analytical results is excellent also for these
cases.
As regards the cases with inlet or .otttlet throttling, these are
now being analyzed and the results will be given in a later report.
Nomenclature
- 19 -
Symbol Definition Units
d
F
Fo
f
H
L
m / F
P
A P
Q
q / A
(q/A)CR
(q/A)BO
t
A t sub
V
V
X
XCR
XBO
P
Diameter
Cross section of heated duct
Outlet a r ea of r i s e r
Frequency
Liquid level
Heated length
Mass velocity
Pressure
Pressure drop over test section
Pressure drop over throttlevalve
Power input
Surface heat flux
Critical surface heat flux
Burnout heat flux
Temperature
Inlet sub-cooling
Volume of test section
Fluid velocity
Steam quality
Critical steam quality
Burnout steam quality
. Density
Resistance factor for throttle
m2m
2in
i
~isecm
i n
kg/ m" sec
atg
mm HO
mm H...0
kW
W/cm2
W/cm2
W/cm2
°C
°c3m
m/sec
Dimensionless
Dimensionless
Dimensionless
kg/m
Dimcnsionles svalve
- 20 -
Bibliography
1. KM Becker, G Hernborg and M BodeAn Experimental Study of Pressure Gradients for Flow ofBoiling Water in a Vertical Round Duct (Part 4, 2, 3 and 4),Reports AE-69, AE-70, AE-85 and AE-86, AktiebolagetAtomenergi, Stockholm, Sweden.
2. S Z Rouhani and K M BeckerMeasurements of Void Fractions for Flow of Boiling HeavyWater in a Vertical Round Duct, Report AE-108, Aktiebola-get Atomenergi, Studs vik, Sweden.
3. KM Becker et al. , IMeasurements of Burnout Conditions for Flow of Boiling Waterin Vertical Round Ducts (Part 1 and 2), Reports AE-87 andAE-114, Aktiebolaget Atomenergi, Studsvik, Sweden.
4. KM Becker and P PerssonAn Analysis of Burnout Conditions for Flow of Boiling Waterin Vertical Round Ducts, Report AE-113, Aktiebolaget Atom-energi, Studsvik, Sweden.
5. KM Becker and G HernborgMeasurements of Burnout Conditions for Flow of Boiling Waterin a Vertical Annulus, Trans. ASME Paper 63-HT-25
6. KM BeckerBurnout Conditions for Flow of Boiling Water in Vertical RodClusters, AICHE Journal, March 1963
7. S JahnbergA One -dimensional Model for Calculation of Non-Steady Two-Phase Flow, Paper presented at EAES-Symposium, StudsvikOctober 1-962.
8. R P Mathisen, G Hernborg and L ValkingNatural Circulation Experiment. Description of the Loop andits Behaviour, Including Some Test Results, Report R4-172/RPL.-641, Aktiebolaget Atomenergi, Studsvik, Sweden.
9. • J G CollierHeat Transfer and Fluid Dynamic Research as Applied to FogCooled Power Reactors, Report AECL.-1631, June 1962.
- 21 -
Table I. Burnout Data
Natural Circulation
p
g/cm
20
30
40
50
60
70
20
30
40
' sub
°C
4 . 1
3 . 2
2 . 8
2 . 1
2 . 2
2 . 4
70
70
115
m/F
kg/m s
500
563
630
732
805
900
q/A
W/cm2
51.5
58.8
67.0
75.7
80.5
79.0
Forced Circulation
310
350
350
51.5
58.8
67,0
XBO
%
52.6
56.2
60.0
60.9
61.4
51.7
0.70
0.75
0, 80
AIR COOLED CONDENCER
LEGENDH- RISER HEIGHTI-INDICATORP-PRESSURER-RECORDERT-TEMPERATURE
STEAM SEPARATOR
LIQUID SURFACE
H
LOWER ELECTRODEi
VENTURIMETER htffi-H1 2 3 A S « 7 • I t t f l Q
DIFFERENCE PRESSURE GAUGE
FIG 1 NATURAL CIRCULATION LOOP
TO CONDENSER
SO
LIQUIDSURFACE
CONDENSATE FROM
CONDENSER ~~*"
TO INLET OFTEST SECTION
FROM TEST SECTION
Fig. 3, Steam separator.
TO DRAIN
• ELECTRODE
• INLET TEMPERATURE' THERMOCOUPLE
TURBINEMETER ORVENTURIMETER
M ) MANOMETER
Fig. 4. Flow diagram for loopwithout steam separator,
800
600
400
X
+oo
vo
10152030405060
"-THRESHOLD OF INSTABILITYAND BURNOUT
INLET TEMPERATURE, t,,, = 20*CINNER DIAMETER, d = 10 mmHEATED LENGTH, L=4890
10 20 30 40 50 , . , , 60SURFACE HEAT FLUX, q|A( W|cm*
Fig. 5. Measured mass velocities.
INLET TEMPERATURE, tto =100 CINNER DIAMETER,d*10mmHEATED LENGTH, t"4890
THRESHOLD OF INSTABILITYAND BURNOUT
30 40 50 , . , 60SURFACE HEAT FLUX, qJA,W|cma
Fig. 6. Measured mass velocities.
INNER DIAMETER,d=10mmHEATED LENGTH, L=A890
20 30 40 50 60 70PRESSURE, p, kg|cm2
Fig. 7. Exit steam quality at onset of oscillations.
1500
o>
1000
K-
8
Ulen
500
ONSET OF INSTABILITY
M 0o 20A 30
>aoO50vSO•7 0
60 70 80SURFACE HEAT FLUX, WJcm2
20 60 100 120 140 160POWER DENSITY, OJV,kW/liter
Fig. 8. Effect of pressure.
*|F-= P=10atg<|/A=12
P=20otgqJA= 51. S wjem1
10TIME, T, see.
Fig. 9. Traces of oscillations.
wjcm1
"q(A=75.7
10TIME, T, s«c.
Fig. 10. Traces of oscillations.
0.7
0.6
"oUl
o
§ 0.4oUJDCU.
0.3
0.1
0
r—
i
_ —
r— —,
10 20 30 40 50 60
PRESSURE, p, kgjcm2
Fig. 11. Measured frequencies.
mJF
P=20otg
q|A=16.5 w|cm2
at =2.6«C
s = 3.3 »C
BURNOUT
q(A=51.5 w|cmJ
a t = 3 . 5 "C
10TIME, T, sec.
Fig. I 2. Traces of oscillations.
1.0
S
w0.5tft
o
ffio NATURAL CIRCULATIONCqJA TO BE TAKEN
FROM FIGURE 8).o FORCED CIRCULATION (THE q/A-VALUES ARE
EQUAL TO THE CORRESPONDING NATURALCIRCULATION VALUES). , .
10 20 30 40 50 60 70 80PRESSURES, kgjcm2
Fig. 13. Comparison between naural and forcedcirculation burnout data.
1500
u.•e
1000
ooUJ
500
•
• I,11
•
1 ONSET OF IN
o 2.1 S 0.3v 7.2 ± 0.2o 11.0 S0.2A 16.0 ±0.2
^
\STABILITY^
I4-5035 mmt = 50 otg
nu. _ -
- « . A
•
C
7.2 *C
•
•
**^*^. IBURNOU1
10 20 30 40 50 60 70 60SURFACE HEAT FLUX, W cm2
» • 1 i i .. —«—
20 60 eo 100 120 UO 160POWER DENSITY, o|v,kW/tit«r
Fig. 14. Effect of inlet subcooling.
100
"g 80
6 0
20
I
1
V
P != 50 atg* 5S3S mm _,.
. —
ONSET OF INSTABILITY
|
BURNOUT
~ ~ - — — •
u
I
i
>>•—
1 — - - .
I* 6 8 10 12 14 IS 18INLET SUBCOOLJNG TEMPERATURE,
Fig. 15. Effect of inlet subcooling on critical and burnoutheat fluxes.
20°C
200
1150
100
p= 50 otg
50
\
e 20 mm ID, WITH STEAM SEPARATOR .
A 10 mm ID.WITHOUT STEAM SEPARATOR.
50 100 150 200INLET SUBCOOUNG TEMPERATURE, At J u b , °C,
Fig. 16. Effect of inlet subcooling on critical power density.
250
1500
2.0 i 0.31.9 ±0.32.1+0.32.0+0.3
60 70 , 80SURFACE HEAT FLUX, W cm*
80 100 120 140 160POWER OENSITY, Q/V, kwflitar
Fig. 17. Effect of liquid level.
0.7
tz<os:<UJ
0.6
0.5
ONSET OF INSTABILITY
5600 5700 5800 5900 6000LIQUID LEVEL, H,mm
Fig. 18. Effect of liquid level on critical and burnoutsteam qualities.
1506
»00
tu
into
500
2.1 +0.3X 2.0 +0.3
2.2 +<U2.4 iOA
FULLY OPEN VALVE0.27 ± 0.031.68 + 0.084.30 ±
*o SO SO 70 SOSURFACE HEAT FLUX, Wjcm*
20 • 0 190 120 UO ISOPOWER 0EM5ITY, ofv, Waite
Fig. 19. Effect of inlet throttling.
1500
- i .
»00
oo
inV)
500
11 i 0.211 i 0.2
o 11 i 0.2X 1 1 + 0.2
11 t 0.2
FULLY OPEN VALVE0.61 t 0.061.38 t 0.073.2' i 0.2
60 70 80SURFACE HEAT FLUX, Wjcm2
20 80 100 120 140 160POWER DENSITY, QJV, kW/liter
Fig. 20. Effect of inlet throttling.
1.0p*50 atgH= 5835 mm
— t r
a
iUi
COI-oz
CD
0.5- -o- - NATURAL CIRCULATION, * t s l l h - 2 °C , \ , ̂ _B
- . ^ . - N A T U R A L CIRCULATION, * t ^ M f C J i 5 < ^ < 7 8
FORCED CIRCULATION (THE qJA-VALUES AREEQUAL TO THE CORRESPONDING NATURALCIRCULATION VALUES).
500 1000 1500PRESSURE DROP OVER THROTTLE VALVE FOR NATURAL CIRCULATION,
Fig. 21. Effect of inlet throttling on burnout.
2000a Pj , mm H2OJ
1503
o 2.1 ±0.3»3.1 10.4o 3.0 i 0.6
3.2 t OX
60 70 , «05USF/CE KEAT FLUX, Wjcms
120 HO ISOPOWER DENSITY, ojv, kW/Ut«r
Fig. 22. Effect of outlet throttling.
1500 :
t/i
Xen
LL.
• c
100 Q
ooUJ
ent/)
500
H ~ BÖJS rnrnp~ 50 atg suh
o 3.0 i 0.63.1 i 0.5
o 3-.4 i 0.44.2 i 0.84.5 t 0.5
FULLY OPEN VALVE1.32 i 0.186.7 i 0.3
16.1 t O.S52.8
ONSET OF INSTABILITY
BURNOUT
SURFACE HEAT FLUX. W cm
20 40 60 80 100
FIG. 23.
120 MO 160POWER DENSITY, QJV, kW/liter
EFFECT OF INLET AND OUTLET THROTTLING.
1500
i.PREDICTED
-MEASURED
\
\
p—10 o
-ONSET OF INSTABILITY
I I
50 SURFACE HEAT FLUX,
p»30otg
»ONSET OF INSTABILITY
SO SLKFACS HEAT F L U X , q|A W | c m s
Fig. 24. Comparison between analytical andexperimental results.
XX»
rPREDICTED-
\
-MSASURED
X -jONSCT OF 11
X
p»40otg
STABILITY
SURFACE HEAT FlUX, q|A,
^MEASURED
PREDICTED— " * * v
ON! 6T OF INSTABII
60 SURFACE HEAT FLUX, ijJA.Wjcm2
«0 SURFACE HEAT FLUX.qjA.Wjen?
Fig. 25. Comparison between analytical andexperimental results.
100
CMM
Q
3 60u.
5tu
DC
3
BURNOUT WITHOUT OSCILLATIONS.
o PRESENT MEASUREMENTSA ANALYTICAL RESULTS
<o
§ o10 20 30 50 60 70 .80
PRESSURE, p, kgjcrr/
Fig. 26, Comparison between experimental and analyticalresults.
CM
o•"5-100
-_ 80X *
_iu.5 60
UJ
UJu
ocw
0 2 0
CR
IT
0
p= 50 atg
H= 5835 mm
t
) EXPERIMENTAL RESULTS
» MINHLlf t f^A l
t
. RESULTS
~^- , _^
t
t
-
-
3 2 L, 5 8 10 12 U 16 18 20INLET SUBCOOLING TEMPERATURE, ats u b ,°C
Fig. 27. Comparison between experimental and analytical results.
LIST OF PUBLISHED AE-REPORTS
1—60. (See the back cover earlier reports.)61. Comparative and absolute measurements of 11 inorganic constituents of
38 human tooth samples with gamma-ray spectrometry. By K. Samsahland R. Söremark. 19 p. 1961. Sw. cr. 6:—.
62. A Monte Carlo sampling technique for multi-phonon processes. By ThureHögberg. 10 p. 1961. Sw. cr. 6:—.
63. Numerical integration of the transport equation for infinite homogeneousmedia. By Rune Håkansson. 1962. IS p. Sw. cr. 6:—.
64. Modified Sucksmith balances for ferromagnetic and paramagnetic mea-surements. By N. Lundquist and H. P. Myers. 1962. 9 p. Sw. cr. 6:—.
65. Irradiation effects in strain aged pressure vessel steel. By M. Grounesand H. P. Myers. 1962. 8 p. Sw. cr. 6:—.
66. Critical and exponential experiments on 19-rod clusters (R3-fuel) in heavywater. By R. Persson, C-E. Wikdahl and Z. Zadworski. 1962. 34 p. Sw. cr.
67. On the calibration and accuracy of the Guinier camera for the deter-mination of interplanar spacings. By M. Möller. 1962. 21 p. Sw. cr. 6:—.
68. Quantitative determination of pole figures with a texture goniometer bythe reflection method. By M. Möller. 1962. 16 p. Sw. cr. 6:—.
69. An experimental study of pressure gradients for flow of boiling water ina vertical round duct. Part I. By K. M. Becker, G. Hernborg and M.Bode. 1962. 46 p. Sw. cr. 6:—.
70. An experimental study of pressure gradients for flow of boiling water ina vertical round duct. Part I I . By K. M. Becker, G. Hernborg and M.Bode. 1962. 32 p. Sw. cr. 6r—.
71. The space-, time- and energy-distribution of neutrons from a pulsedplane source. By A. Claesson. 1962. 16 p. Sw. cr. 6:—.
72. One-group perturbation theory applied to substitution measurementswith void. By R. Persson. 1962. 21 p. Sw. cr. 6:—.
73. Conversion factors. By A. Amberntson and S-E. Larsson. 1962. 15 p. Sw.cr. 10:—.
74. Burnout conditions for flow of boiling water in vertical rod clusters.K M B k 1962 44 S
Burnout conditions for flow of boiling wBy Kurt M. Becker. 1962. 44 p. Sw. cr. 6:—.
75. Two-group current-equivalent parameters for control rod cells. Autocodeprogramme CRCC. By O. Norinder and K. Nyman. 1962. 18 p. Sw. cr.6;—.
76. On the electronic structure of MnB. By N . Lundquist. 1962. 16 p. Sw. cr.6:—.
77. The resonance absorption of uranium metal and oxide. By E. Hellstrandand G. Lundgren. 1962. 17 p. Sw. cr. 6:—.
78. Half-life measurements of »He, »N , »O, »F, »Al , "Se™ and "»Ag. By J.Konijn and S. Malmskog. 1962. 34 p. Sw. cr. 6:—.
79. Progress report for period ending December 1961. Department for Reac-tor Physics. 1962. 53 p. Sw. cr 6:—.
80. Investigation of the 800 keV peak in the gamma spectrum of SwedishLaplanders. By I. D . Andersson, I. Nilsson and K. Eckerstig. 1962. 8 p.Sw. cr. 6,:—.
81. The resonance integral of niobium. By E. Hellstrand and G. Lundgren.1962. 14 p. Sw. cr. 6:—.
82. Some chemical group separations of radioactive trace elements. By K.Samsahl. 1962. 18 p. Sw. cr. 6:—.
83. Void measurement by the [y, n) reactions. By S. Z. Rouhani. 1962. 17 p.Sw. cr. 6,i—.
84. Investigation of the pulse height distribution of boron frifluoride pro-portional counters. By I. O. Andersson and S. Malmskog. 1962. 16 p.Sw. cr. 6,:—.
85. An experimental study of pressure gradients for flow of boiling waterin vertical round ducts. (Part 31. By K. M. Becker, G. Hernborg and M.Bode. 1962. 29 p. Sw. cr. 6r—.
86. An experimental study of pressure gradients for flow of boiling waterin vertical round ducts. (Part 4). By K. M. Becker, G. Hernborg and M.Bode. 1962. 19 p. Sw. cr 6:—.
87. Measurements of burnout conditions for flow of boiling water in verticalround ducts. By K. M. Becker. 1962. 38 p. Sw. cr. 6:—.
88. Cross sections for neutron inelastic scattering and (n, 2n) processes. ByM. Leimdörfer, E. Bock and L. Arkeryd. 1962. 225 p. Sw. cr. 10:—.
89. On the solution of the neutron transport equation. By S. Depken. 1962.43 p. Sw. cr. 6:—.
90. Swedish studies on irradiation effects in structural materials. By M.Grounes and H. P. Myers. 1962. 11 p. Sw. cr. 6:—.
91. The energy variation of the sensitivity of a polyethylene moderated BFjproportional counter. By R. Fräki, M. Leimdörfer and S. Malmskog. 1962.12. Sw. cr. 6 r - .
92. The backscaftering of gamma radiation from plane concrete walls. ByM. Leimdörfer. 1962. 20 p. Sw. cr. 6:—.
93. The backscattering of gamma radiation from spherical concrete walls.By M. Leimdörfer. 1962. 16 p. Sw. cr. 6s—.
94. Multiple scattering of gamma radiation in a spherical concrete wallroom. By m. Leimdörfer. 1962. 18 p. Sw. cr. 6:—.
95. The paramagnetism of Mn dissolved in a a n d B brasses. By H. P. Myers
and R. Westin. 1962. 13 p. Sw. cr. 6:—. ^
96. Isomorphic substitutions of calcium by strontium tn calcium hydroxy-apatile. By H. Chrisfensen. 1962. 9 p. Sw. cr. 6:—.
97. A fast lime-to-pulse height converter. By O. Aspelund. 1962. 21 p. Sw. cr.6:—.
98. Neutron streaming in D2O pipes. By J. Braun and K. Randen. 196241 p. Sw. cr. 6:—.
99. The effective resonance integral of thorium oxide rods. By J. Weitman.1962. 41 p. Sw. cr. 6:—.
1C0. Measurements of burnout conditions for flow of boiling water in verticalannuli. By K. M. Becker and G. Hernborg. 1962. 41 p. Sw. cr. 6:—.
101. Solid angle computations for a circular radiator and a circular detector.By J. Konijn and B. Tollander. 1963. 6 p. Sw. cr. 8:—.
102. A selective neutron detector in the keV region utilizing the "F(n, y)MFreaction. By J. Konijn. 1963. 21 p. Sw. cr. 8:—.
103. Anion-exehange studies of radioactive trace elements in sulphuric acidsolutions. By K. Samsahl. 1963. 12 p. Sw. cr. 8:—.
104. Problems in pressure vessel design and manufacture. By O. Hellströmand R. Nilson. 1963. 44 p. Sw. cr. 8:—.
105. Flame photometric determination of lithium contents down to 10-3 ppmin water samples. By G. Jönsson. 1963. 9 p. Sw. er. 8:—.
1C6. Measurements of void fractions for flow of boiling heavy water in avertical round duct. By S. Z. Rouhani and K. M. Becker. 1963. 2nd rev.ed. 32 p. Sw. cr. 8:—.
1C7. Measurements of convective heat transfer from a horizontal cylinderrotating in a pool of water. K. M. Becker. 1963. 20 p. Sw. cr. 8:—.
108. Two-group analysis of xenon stability in slab geometry by modal expan-sion. O. Norinder. 1963. 50 p. Sw. cr. 8:—.
109. The properties of CaSOjMn thermoluminescence dosimeters. B. Bjärn-gard. 1963. 27 p. Sw. cr. 8:—.
110. Semianalytical and seminumerical calculations of optimum materialdistributions. By C. I. G. Andersson. 1963. 26 p. Sw. cr. 8:—.
111. The paramagnetism of small amounts of Mn dissolved in Cu-AI andCu-Ge alloys. By H. P. Myers and R. Westin. 1963. 7 p. Sw. er. 8:—.
112. Determination of the absolute disintegration rate of Cs137-sources by thetracer method. S. Hellström and D. Brune. 1963. 17 p. Sw. cr. 8 r - .
113. An analysis of burnout conditions for flow of boiling water in verticalround ducts. By K. M. Becker and P. Persson. 1963. 28 p. Sw. cr 8:—.
114. Measurements of burnout conditions for flow of boiling water in verticalround ducts (Part 2). By K. M. Becker, et al . 1963. 29 p. Sw. cr. 8:—.
115. Cross section measurements of the ssNifn, p)s!Co and MSi{n, a)26Mg reac-tions in the energy range 2.2 to 3.8 MeV. By J. Konijn and A. Lauber1963. 30 p. Sw. cr. 8:—.
116. Calculations of total and differential solid angles for a proton recoilsolid state detector. By J. Konijn, A. Lauber and B. Tollander. 1963. 31 p.Sw. cr. 8:—.
117. Neutron cross sections for aluminium. By L. Forsberg. 1963. 32 p.Sw. cr. 8:—.
118. Measurements of small exposures of gamma radiation with CaSOcMnradiothermoluminescence. By B. Bjärngard. 1963. 18 p. Sw. cr. 8:—.
119. Measurement of gamma radioactivity in a group of control subjects fromthe Stockholm area during 1959—1963. By I. P Andersson, I. Nilssonand Eckerstig. 1963. 19 p. Sw. cr. 8:—.
120. The thermox process. By O. Tjälldin. 1963. 38 p. Sw. cr. 8:—.
121. The transistor as low level switch. By A. Lydén. 1963. 47 p. Sw. cr. 8:—.
122. The planning of a small pilot plant for development work on aqueousreprocessing of nuclear fuels. By T. U. Sjöborg, E. Haeffner and Hult-gren. 1963. 20 p. Sw. cr. 8:—.
123. The neutron spectrum in a uranium tube. By E. Johansson, E. Jonsson,M. Lindberg and J. Mednis. 1963. 36 p. Sw. cr. 8:—.
124. Simultaneous determination of 30 trace elements in cancerous and non-cancerous human tissue samples with gamma-ray spectrometry. K. Sam-sahl, D. Brune and P. O. Wester. 1963. 23 p. Sw. cr. 8:—.
125. Measurement of the slowing-down and thermalization time of neutronsin water. By E. Möller and N. G. Sjöstrand. 1963. 42 p. Sw. cr. 8:—.
126. Report on the personnel dosimetry at AB Atomenergi during 1962. ByK-A. Edvardsson and S. Hagsgärd. 1963. 12 p. Sw. cr. 8:—.
127. A gas target with a tritium gas handling system. By B. Holmqvist andT. Wiedling. 1963. 12 p. Sw. cr. 8 : - .
128. Optimization in activation analysis by means of epithermal Neutrons.Determination of molybdenum in steel. By D. Brune and K. Jirlow. 1963.11 p. Sw. cr. 8:—.
129. The Pi-approximation for the distribution of neutrons from a pulsedsource in hydrogen. By A. Claesson. 1963. 18 p. Sw. cr. 8:—.
130. Dislocation arrangements in deformed and neutron irradiated zirconiumand zircaloy-2. By R. B. Roy. 1963. 18 p. Sw. cr. 8:—.
131. Measurements of hydrodynamic instabilities, flow oscillations and bur-nout in a natural circulation loop. By K. M. Becker, R. P. Mathisen, O.Eklind and B. Norman. 1964. 21 p. Sw. cr. 8:—.
Förteckning över publicerade AES-rapporter
1. Analys medelst gamma-spektrometri. Av D. Brune. 1961. 10 s. Kr 6:—.
2. Besträlningsförändringar och neutronatmosfär i reaktortrycklankar —några synpunkter. Av M. Grounes. 1962. 33 s. Kr 6:—.
3. Studium av sträckgränsen ! mjukt stål. G. Östberg, R. Attermo. 1963.17 s.Kr 6:—.
4. Teknisk upphandling inom reakloromrädet. Erik Jonson. 1963.64 s. Kr. 8.—.
Additional copies available at the library of AB Atomenergi, Studsvik, Nykö-ping, Sweden. Transport microcards of the reports are obtainable throughthe International Documentation Center, Tumba, Sweden.
EOS-tryckerierna, Stockholm 1964