.
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.
- -
-
TOFT.
ORNL P
1324
.
..
-
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.
.
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.
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1125 LALE
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MICROCOPY RESOLUTION TEST CHART
NATIONAL BURE AU OF STANOAROS - 1963

*
C
much
LEGAL NOTICE
This report was prepared as an account of
Government sponsored work. Neither the
United States, nor the Commission, nor any
person acting on behalf of the Commission:
A. Makes any warranty or representa-
tion, expressed or implied, with respect to
the accuracy, completeness, or usefulness
of the information contained in this report,
or that the use of any information, appa-
ratus, method, or process disclosed in this
report may not infringe privately owned
rights; or
B. Assumes any liabilities with respect
to the use of, or for damages resulting from
the use of any information, apparatus,
method, or process disclosed in this report.
As used in the above, “person acting on
behalf of the Commission” includes any em-
ployee or contractor of the Commission, or
employee of such contractor, to the extent
that such employee or contractor of the
Commission, or employee of such contractor
prepares, disseminates, or provides access
to, any information pursuant to his employ-
ment or contract with the Commission, or
his employment with such contractor.
.
-
ORNU -P-1324
CONF-650407-66. ILDERS
BEHAVIOR OF RADIOIODINE IN THE CONTAINMENT MOCKUP FACILITY*
3+961 LONAC
G. W. Parker
W. J. Martin
G. E. Creek
C. J. Barton
Reactor Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
brancinha
Introduction - Description of Equipment
The Containment Mockup Facility (CMF) is a relatively small versatile
facility located within a hot cell for determination of fission product release
from irradiated fuel materials and for study of the transport properties of
the resulting fission product aerosols. The facility, shown in Fig. 1, and the
numerous modifications of its instrumentation that have been made since its .
inception have been discussed in a series of progress reports (1-4). Important
features of the equipment are the furnace where metal-clad Uoc fuel elements
are heated by means of high-frequency (normally 2 megacycle) induction heating;
a 180-liter stainless steel tank where the fission product aerosol can be held
in air or steam-air under an initial 30 psig pressure for any desired length of
time, and a number of devices for sampoing the tank atmosphere. Details of the
complex filter pack used to determine the distribution of radioiodine in the
aged tank aerosol are shown in Fig. 2.
Several variables affecting the behavior of radioiodine in the CMF have
been studied in a series of release tests initiated with the use of 1311 tracer
and extended to other fission products released from U02. Details of previous
tests in this series were given in a previous report (3).
The earlier tests were all performed in air (i.e., in the absence of steam),
while the present part of the series was primarily directed toward a study of
the behavior of iodine in a mixture of steam and air at about 30 psig or in a
similar steam-air mixture with mixed hydrocarbon gases. In all tests the 1311
tracer was prepared with enough 1271 carrier to provide a total iodine concentration
of approximately 2 mg/m in the CMF tank.
The experiments were conducted essentially as described in the above-mentioned
report (3) except that when steam pressure was desired before the iodine release,
22 psia was added to the tank, followed by air in amounts just sufficient to reach
~ 45 psia. The presence of steam in the containment prior to the release of
fission products provides realistic accident simulation according to most
accident models for pressurized-water reactors.
*Research sponsored by the U. S. Atomic Energy Commission under contract with
the Union Carbide Corporation.
PATENT CLEARANCE OBTAINED. RELEASE ACT with
THE PUBLIC IS APPROVED. PROCEDURES
ARE ON EILE IN THE RECEIVING SECTION,
-LEGAL NOTICE-
TWI report no prepared wa mccount of component spoorond work. Molchor the Valled
statos, kor the Conalulon, por ww pornod acting on behalf of the Counsafon:
A. Mos uyninaty or reprenotatou, read or inplied, we rupect to w. icry.
racy, completeness, or wanaw of the taformation contained lado roport, or that the we
of way la formation, appunto, methodha or procmi dieclound ta tus report may not infringe
prinuly ownd der or
B. imam ulladiuuan no nepoct to the wool, or for denne renibg Irom the
un ol way laloration, appentue, whos, or process dinclound in Worsport.
Ao wad lo the above, "per on the a betalt of the Conniesion" include my tn.
ployee or contractor of the coun ten, of employee of much contractor, to the adent that
orca ou play. or contractor of the Connolonor emploru a much contractor proper,
dianninal, or provides acuto, may taformation purnum ho Me onploynnt or contract
with the Conoston, or Me employment mul much contractor.

UNCLASSIFIED
ORNL-OWG. 64-4999
AIR --
WATER
AIR
WATER
VACUUM
-- VACUUM
.8888
-VENT
DE VENT
- STEAM
DVENTU
se WASH SOLUTION LINE
COUNTER
to TO NUCLEI
Lesezee
coopoo
Q10
o
F
DISTILLE
...
O WASH TANK
® 20 LITER CARBOY
JU GAL. S.S. HOLD-UP TANK
☺ COOLING BATH
CRUCIBLE AND SAMPLE
© INDUCTION HEATER COIL
QUARTZ TUBE
ROTAMETER
CHARCOAL TRAP
O VACUUM PUMP
ANDERSON "IMPACTOR" SAMPLER
3 ORIFICE
® SOLENOID VALVE
© MILLIPORE FILTER AND CHARCOAL
MILLIPORE FILTER
RASHIG RING TRAP
CHARCOAL TRAP
ROUGHING FILTER
9 ABSOLUTE FILTER
20 COPPER SCREENS (3 :
CHARCOAL PAPER (3)
~ CHARCOAL CARTRIDGES
23 ABSOLUTE FILTER
COPPER SCREENS (4)
3 PLALINIZED ALUMINA
SO DIFFUSION TUBE (Ag lined Cu tubing)
DIFFUSION TUBE (rubber tubing)
3 DIFFUSION TUBE (charcool-lined S.S. tube )
29 SAMPLER HOLES
♡ FAN
* CUTAWAY, SHO: .NG PLATE OUT
SAMPLER
.................
.-..
-
@
.
lolx
.
.

SAMPLE
ARGON
DRAIN
Fig. 1. Schematic Diagram of the Confinemer
in
Pacility (CMF).
OAHLOWG 65.4

POSITION 1, Q @
FROM
TANK
TO BACK-UP COLO TRAD
AND EXHAUST
33' 6
TANDEM FILTER PACK
TANDEM FILTER PACK
ROUGH FILTER
ABSOLUTE FILTER
SILVER SCREENS
CHARCOAL PAPER FILTERS
TEFLON BUSHING
CHARCOAL CARTRIDGE
THERMOCOUPLE WELL
© Ag-PLATED DIFFUSION TUBE
© CONNECTOR
CHARCOAL LINED DIFFUSION
TUBE
TO ROTAMETERS, COLO TRAPS,
AND EXHAUST
Fig. 2. Filter Pack with Diagram of Tandem
Diffusion Tube Arrangements.
Iodine Behavior in Air and in Steam and Air
In run 6-11 (labeled run E in the previous progress report (3), but included
in Table 1 for comparison), only 30 psia of air was present in the containment
tank when the iodine tracer was vaporized by heat applied with a gas torch. Air
flowed past the sample in the furnace tube to displace the iodine into the
containment tank. A fan was operated for 1 min to obtain complete mixing of the
aerosol in the tank. After 4 hr retention in the tank under air pressure, the
excess air and any accompanying airborne iodine was displaced in three separate
steps through separate filter packs for determination of the distribution of
oxidation states and forms of the radioiodine. The first step was depressurization
of tha tank; the second was an argon sweep of the tank; and the third was an air
sweep. Finally, the effectiveness of the charcoal adsorption system was
calculated, and the percent penetration for a given bed depth was recorded. The
observed value of 13% of the total iodine displaced from the containment tank
was significantly higher than expected. Desorption during the two sweep steps
accounted for approximately half the total.
sieme con m'n mietinte: "..Invoice
in
H
Iodine Deposition and Desorption in the Containment Mockup Facility
Table 1.
Percent of Total. Iodine Released
Sicam-Air
Run 6-256 Run 8.40
Stcam-Air and Organics
Run 9-10% Run 10.9€
Run: 6-11°
Run 7-160
Run 10-28'
Iodinc held in conta inmcr.t tank
Retained on tank walls
79.6
60.8
38.2
18.3
24.4
:
20.9
19.3
52.9
34.9
43.5
47.3
54.0
Collector in steam condensate
58.2
95.7
79.6
72.2
92.2
61.8
Total reter:tion
66.2
82.6
Iodinc scmoved from lank
12.9
2.4
8.5
6.2
By pressure rcicase
14.6
3.0
2.4
13.3
1.2
15.9
7.2
By argon displacement
15.7
0.3
0.5
1.2
1.7
1.8
2.6
By air sweep
32.1
14.6
13.3
27.0
2.6
Total semoved, airbornc
6.5
1.9
0.8
2.2
6.1
0.9
lodine removed on test samples
1.7
Distribution of airbornc iodine from tank
8.16
0.1
0.5
1.5
0.01
0.3
0.03
2.3
5.3
0.8
6.4
2.6
8.5
9.1
2.0
16.3
3.0
0.4
0.4
15.8
1.7
Retained on filters
Retaincd on silver 'copper screens
Retained on charcoal papers
Retained in charcoal contridges
Penctration loss throuch, in. charcoal
2.0
0.3
9.1
16.4
0.6
. 2.3
6.6
3.8
0.17
0.3
0.8
0.5
0.01
21
0.3
1.6
Pen:tralinziodinc (% of inventory)
0.5
2.5
1.2
lodine was relcased to the ccata insient sholl filled with filtered air only at 30 psia (containscrit line at full p:cSSUIC, 4 hr).
Plodine selcasco in strap. (20 psia) and oi: (20 psia) under conditions providing a lari:et amount of condensate (contaist.eni tisac ut full pressure,
4 hr).
Clodinc released in sican (~21 psia) and oir in 21 psia) and held in con!ainment 18 hs.
"An undefcrinincd amount of organic material, accione, and solid Co, was inadvertently included in the jodine tracer pocparaliosis. Rolcase was
with steam (~20 psia) and air (~20 psia); held in containment Sir.
Cir. 9-10 (secam, ^22 psia; nir, ~22 psia; contain:cnt !imc, 5 hr) and 10.7 (stcan, ~22 psia; air, ~22 psia; contain:.:(.nl tio, 16 :r) 500 cm o! mixed
hydrocarbons gxepared by hydrolysis of UC-UC, were cided.
"In 10-2E, VO, was relied above the iodiac is acos which in turn was released when the motion UO, mixiurc licated a quarta a::.; 'ul to i::. .:lting
or softoning point. Released with steam (?2 psia) and air (22 psia); Ihr containment tinc.
Pono organic membranc filter which probably scacled with and sclained some molecular iodine in addition to particulate iudins.
-4-
In the first of the steam-air experiments, run 6-25, an unexpected
accumulation of condensate occurred in the furnace tube. The water had to be
boiled cut with the iodine, and all but 2.6% of the iodine was retained in the
tank. Initially, the results suggest a rather effective washout for the steam
condensation process. However, it is believed, instead, that most of the iodine
in this case was transferred into the tank in water droplets instead of in a
rue gaseous form and that it was readily adsorbed on the tank walls in this
form, thus accounting for tlie 60% tank retention (two to three times as much as
in subsequent runs) observed for this run. Correspond ingly low (2.6%) airborne
values were obtained in this run.
In run 8-4, the excess steam condensate was controlled by the use of tank
insulation and heating wires. In this run the aerosol was held 18 hr in the
containment tank before displacement through the filter pack system. Only 1.7%
of the iodine was desorbed by the air sweep, but a total of 6.5% was displaced
by the three steps: pressure letdown, argon gas displacement, and air sweep.
In comparing the charcoal adsorption behavior of the airborne iodine i or
these two runs with that in air, it appears that the amount of iodine penetrating
0.75 in. of charcoal was three times greater in the first run than in the secona
(0.3% for 8-4 compared to 0.08% for 6-25 and 0.01% for 6-11). Gas sample data
i'or the three runs (Fig. 3) show about a factor of 10 reduction in airborne
iodine concentration for run 6-11 but only a factor of about 3 reduction in the
steam runs over the 5-hr period. Over a longer period, run 8-4 showed a sight
continuous increase in airborne iodine concentration in the interval between 8
and 18 hr. Thus, it can be inferred that a dry metal surface is a better iodine
adsorber than a wet one, and the presence of steam in containment either enhances
the production of penetrating iodine forms or the high humidity correspondingly
diminishes the adsorption on charcoal.
Iodine Behavior in Steam-Air Mixtures Containing Organic Gases
There has been much speculation about the origin of 'penetrating forms" of
radioiodine encountered in various nuclear safety studies; however, no strong
case has been advanced for a correlation of the presence of a particular organic
gas (such as methane) with the production of this form of iodine. Methyl iodide
has been consistently shown to be one of the principal components of the organic
iodine fraction.
While it appears in some cases that radioiodine has reacted directly in some
way with organic materials in the air, the energetics of the reaction of iodine
with hydrocarbons are not favorable since the C-H bond strength exceeds the C-I
bond strength. The reaction of the methyl radical with free iodine in solution,
on the other hand, has been frequently used as a method of removing this organic
species in radiation chemistry studies.
Attempts to induce the methane-iodine reaction at 200°C in a 10,000 curie
cobalt irradiation facility were unsuccessful. Examination of the rate of
formation of free methyl radicals indicated that only trace quantities o: methyl
iodide could be expected. The mechanism by which the penetrating iodine forms
are produced remains to be demonstrated, but it 18 likely that it involves an
adsorption-desorption activation or local reaction of iodine with organic materials
on metal surfaces.
..
.
ORNL-OWG 65-1316
...

106
.
...
...
..
..
.
L
RUN 6-11 (AIR)
..
....
RUN 6-25
(STEAM-AIR)
....
..
.
..
BIJ ACTIVITY (dis/min)
START
(PRESSURE RELEASE
..
.....
.
RUN 8-4
(STEAM-AIR)
. .
.
.
-
.
.
.
.
106
0
240 480 720 960 1200 1440
TIME FROM MELTDOWIN OR RELEASE (min)
1600
.
Fig. 3.
Change in Iodine Concentration in the CMF Atmosphere.
The third series of experiments conducted in the CMF provided for the
addition of a mixture of hydrocarbon gases derived from the hydrolysis oi uranium
carbide (mainly Uc) by the method described by Bradley and Ferris (2).
This mixture was relatively high in methane (~ 75% by volume), and it contained
hydrogen and more than 30 additional hydrocarbons, most of which were present
in only trace amounts. Mixtures of this type have been carefully analyzed (ó),
and it was felt that they represent a reasonable substitute for accident-generated
organic vapors for which there is no presently available description or
approximate analysis. .
Run 7-16, in which the codine tracer was found to have been prepared with
both acetone and cos inadvertently present in the ampul, is included in this
series. In the subsequent runs (9-10, 10-7, and 10-28), 0.5 liter (STP) of the
above-mentioned mixture of hydrocarbons was added to the 180 liters of steam and
air in the containment shell at 30 psig and 110°C. The hydrocarbon gas was
heated to a variable extent as the iodine sample was vaporized. In run 10-28,
where to was melted, more intensive heating of the gas mix ture occurred than
in the other experiments.
A comparison of the results of runs 7-16, 9-10, and 10-7 (summarized in
Table 1), all of which were made with molecular iodine released into an atmosphere
of steam, air, and organic compounds, shows that the amount of iodine collected by
.
the condensate varied very little, from 47 to 58%.
tank walls varied only from 19 to 24%.
The amount retained on the
.
.
.
.
.
...
In the 10-28 (with voz aerosol) 32% of the iodine remained airborne after
9 hr. Of this arnount, 14.6% Was transferred in the pressure-letdown step and
15.7% in the following argon displacement. Only 1.8% was removed by the air
sweep, indicating relatively little desorption during this operation.
...
.
..
...
.
..
Iodine Deposition on Test Samples
".
-
. '
.
Results of an earlier study of plateout of radioiodine on typical reactor
surface materials in the CMF were reported in the previous progress report (4).
In that test, only air was present as the carrier gas, and tracer 1311 was used
in the absence of voz.
.
.
. .
. .
.
.
Additional plateout studies have been performed during the experiments
described in Table 1, which, wi th one exception (run.6-11), were conducts with
steam-air mixtures in the containment tank. Most of the plateout tests described
l.ere were conducted at surface temperatures in the range 100 to 3000c. Data on
deposition in air obtained in run 6-11 with unheated surfaces are shown ir. Fig. 4.
.
.
.
.
.
.
.
.
In run 6-25 (Fig. 5) the test samples were not heated, except by the
surrounding steam. These samples were therefore initially at about 100ºC and
they quickly cooled (in about 1 hr) to room temperature. The amount of iodine
plateout was determined as a function of exposure time, starting with a few
minutes and extending to about 4 hr. A decided minimum found in the plateout
on stainless steel was a surprise, and this phenomenon is not readily explained.
The relative deposition of iodine was a factor of 3 or 4 lower than on mila
steel. The deposition on painted samples was about 50% lower than on mild steel.
Run 7-16, which was the first of the series in which the tank atmosphere
contained organic gases in addition to steam and air, showed the same dirference
in deposition of iodine on stainless steel and on the other surfaces, as in the
previous experiments. In this case the painted steel actually slightly exceeded.
the mild steel in total uptake of iodine, as shown in Fig. 6. The temperature
profile was similar to that in run 6-25. A decided minimum in the stainless
steel deposition curve seems to indicate that subtle effects were probably
important.
In run 8-4, the tank temperature started at 110°C and dropped, due to added
insulation, slowly to 65° in 2 hr and to 30° in 10 hr. The milå steel samples
were exposed for periods ranging from a few minutes to about 18 hr. The amount
of iodine deposited on these samples continued to increase during the entire
interval. The other two sample positions were occupied by two parallel sets of
stainless steel cylinders, of which one set was exposed at intervals up to 7 hr
and the other set up to 18 hr. A curious resemblance in the two curves (Fig. 7)
showed that time alone was not the controlling effect for deposition on stainless
steel but that geometrical position had an important bearing. In each case the
sample specimens near the tank wall were lower than expect:d by a factor of about
ORNL-OWG 65-1317
ORNL-OWG 64 - 780ER


109
STEEL
PAINTED STEEL
MILO STEEL
PAINTED STEEL
1341 ACTIVITY (dis/min)
'STAINLESS STEEL
134, ACTIVITY (dis/min)
STAINLESS STEEL
5x109
106
LIT
0 40 80 120
TIME (min)
160
.
200
240
N
.
2 .
TIME (hr)
:
Fig. 4. Deposition of Radioiodine on Test
Samples in Run 6-ll.
Fig. 5. Deposition of Radioiodine on Test
Samples in Run 6-25.
10. This seems to indicate that either steam condensation washed iodine oil
these samples or that they just did not receive the same exposure. A rather
important difference between stainless steel and mild steel was again apparent.
In run 9-10 (Fig. 8) painted steel at 120°C exceeded the uptake of mila
steel at 200 and 300° by a factor of about 3. In turn, the deposition of iodine
on mild steel exceeded that on the stainless steel specimens by about a factor
of 8. In this run and in run 10-7 (Fig. 9), the specimens were heated during
the first 1-1/2 hr or until the steam condensation had been about completed.
In run 10-7 the solid steel specimens at 300°C exceeded the stainless steel
in relative iodine uptake by a factor of about 20, while at 200° the factor was
only a little more than 10. The uptake at 300°C on mild steel was unexpectedly
higher than at 200° by almost a factor of 2. This behavior is not reproducible,
as shown by the results of run 10-28, Fig. 10. It may have been due to the
fact that these specimens were allowed to remain in the tank for several hours
after the heating was discontinued. The amount of iodine adsorbed by the test
samples is given in Table 2 as percent of inventory and in terms of deposition
velocity (7).
ORML-grid 05.1313

ORNL-DWG 64-7505

MILD STEEL
MILO STEEL
PAINTED STEEL
X
Kes/min)
STANLESS
STEEL
1315 ACTIVITY (Gis/min)
ÖN
L-
STAINLESS STEEL -
PLATE-OUT SAMPLES
s!
2
os
0
50
100
150 200
TIME (min)
250
300
350
360
.
1200
240
460 720
TIME (min)
Fig. 6. Deposition of Radioiodine on
Test Samples in Run 7-15.
Fig. 7. Deposition of Radioiodine
on Test Samples in Run 8-4.
Differentiating Iodine Forms by Means of a Complex Filter Pack
Plots of the distribution of iodine in successive silver scre' ns and charcoal
papers, obtained after changing atmospheric conditions in the CMF iodine release
and fuel melting tests from air to a steam-air mixture, suggested that some oí
the components of the filter pack were either undergoing changes in capacity or
were experiencing saturation to some extent for a given form of iodine. The
nature of the problem is illustrated in the curves shown in Figs. ll and 12.
intraeus
Diffusion data in the charcoal-lined tubes also showed anomaries, apparently
resulting from the presence of water vapor, and the tubes were subsequently
heated to approximately 100°C. In order to prevent condensation of water in the
filter pack, it was wrapped with electrical tapes to heat it to about 100°C,
beginning with run 10-28. Silver-lined diffusion tubes were connected to charcoal-
lined tubes in the tandem arrangement shown in Fig. 2, and also with the order oſ
OANL OWG 65.1320
ORNL OWG 64.9742

51106

PAINTED STEEL 120°C
200.C
MILO STEEL
more MILO STEEL
o'l actnmir (csts.)
WE ACTITY (dis/min)
TEMPERATURE
_
200
.. STAINLESS STEEL
TEMPERATURE (°C)
- STAINLESS STEEL
3 4
SAMPLE NUMBER
5
6
INSIDE
TANK WALL
DISTANCE FROM TANK WALL (cm)
Impeg
0 1
13. 17- 2125mg
3 4 5 6
SAMPLE NUMBER
i
7
2
Fig. 8. Deposition of Radioiodine
on Heated Samples in Run
9-10.
Fig. 9. Deposition of Radioiodine on
Heated Test Samples in Run 10-7.
OANL - OWG 65.1323
31108

OANL-OWG 65-1322

ARGON SWEEP
- UNHEATEO MILO STEEL
I HEATED MILO STEEL
300°C
HEATEO HILO STEEL
200°C
A PRESSURE RELEASE
BIJ ACTIVITY (Gisimin)
BI! ACTIVITY (Gisimin
UNKCATED STAINLESS STEEL
HEATED STAIFİLESS STEEL
- 200°C
AIR SWEEP
CL TAI:K WALL
HEATED STAINLESS STEEL
300°C
5cm
4cm
1
4 cm
4 cm
- 4 cm med
5 6
4cm
3
2
4
2
3
7
8
4 5 6
SCREEN NUMBER
Fig. 10. Deposition of Radioiodine
on Heated Test Samples in
Run 10-28.
Fig. 11. Distribution of Radioiodine on
Silver Screens in Run 10-28.
to condhatjanticitetan antara satu t
uuassa St Lumia.
Table 2. Deposition of Radioiodine on Test Samples.
Stainless Steel
Painted Steel
Run No.
Time of
Deposition
(min)
Average
Concentration
(mg/mº)
Percent of
lodinc
Inventory on
Sample
Deposition
Velocity. Ve
(cm/sec)
Blild Steel
Percent of
Deposition
Iodine
Inventory on
Velocity, V&
Sample
(cm/sec)
Percent of
lodinc
on
Inventory on
Sample
Deposition
Velocity, V
(cm/sec)
x 10-3
* 10-3
x 10-3
·
6-110
1.1
0.062
2.59
1.1
41.2
0.84
35.4
220
1.0
0.15
6.32
0.22
0.19
8.4
6-250
7-166
'316
1.8
0.031
0.54
0.079
1.5
0.081
1.6
- 10-
1080
1.0
0.19
1.7
0.22
2.0
9-10%
1.2
0.21
5.5
305
1.2
0.0072
0.14
0.073
1.4
9-10°
9-104
305
1.2
0.0078
0.16
0.051
0.98
10-76
963.
1.1
0.18
1.7
963
1.3
0.0017
0.033
0.11
0.75
10-90
10-94
963
1.1
0.0054
0.038
0.13
0.94
10-286
134
1.4
0.015
0.83
0.13
6.9
10-28°
134
1.4
0.49
0.089
3.6
0.012
0.0071
10-280
134
1.4
0.29
0.071
2.9
Run 6-11 was in air; all schoors were in stcam-a is.
B~ 30°C on 6-cm? surface. Temperature variable: 110 to 30°C during cooling.
C200°C on 8-cm? surface.
(300°C on 8-cm? surface.
-11.
OANL-OWG 65-1324
108
ORNL-OWO 65-1325
SILVER LINED TUBES ECHARCOAL LINED TUBE)
(TOP POSITION! 3F (BOTTOM POSITION) 3
7x10% dis/min TOTAL: 515.8x107 dis/min TOTAL: 1
REACTIVE 10DINE PENETRATING IODINE _
70%


30%
ARGON
SWEEP
IS, ACTIVITY (dis/min)
PRESSURE
RELEASE
IODINE ACTIVITY (dis/min)
be AIR SWEEP
6
CHARCOAL PAPER NUMBER
0
120
40 80 120 0 40 60
DISTANCE FROM TUBE ENTRANCE (cm)
Fig. 12. Distribution of Radiolodine
on Charcoal Papers in Run 10-7.
Fig. 13. Data for Tandem Diffusion Tube
in Position 4 after Charcoal
Paper in Run 3.0-7.
the tubes reversed, to see if any form of iodine penetrated both tubes. In
general, it was found that a larger fraction of the iodine passed through the
silver tube than deposited on it; however, the heated-charcoal tube was highly
efficient in either position. Typical curves are shown in Fig. 13. The
corrective measures for sampling iodine in steam-containing atmospheres have been
found satisfactory for the charcoal-containing portionsof the sampler; however,
the silver deposition results are frequently still erratic.
ntrenman master na
Diffusion tube distribution data are compared in Table 3 for runs 9-10,
10-7, and 10-28. The last test was the only one in which V02 was vaporized.
The data are presented graphically in Figs. 14 to 16. The silver-lined tube
retains the reactive iodine fairly efficiently, both Iz and HI, and it will also
retain iodine attached to very small particles (< 200 A diam). The only other
form that could be present at this point is the unreactive gaseous, or penetrating
form. Therefore, the distribution between the silver-lined tube and the charcoal-
lined tube was interpreted as suggesting a rather definite measure of the
ene tinira a
Shisha katikanovar
-12-
Table 3. Distribution of Iodine on Complex Filter Pack Determined by its
Retention in Tandem Diffusion Tubes.
Run
Run
Run
10-28
lodine Diouibution
9.100
10-70
_
_
11'
:
23
Gas-borne lodino reaching charcoal papers (% of
Inventory)
0.65
0.90
lodine collectod by charcoal from sido stroam coloro
charcoal papers (fraction in otro am)
amount of penetrating iodino (% of inventory: product of
above values)
0.26
0.70
0.99
lodine collected by charcoal from side stream after
charcoal papors (traction in stream)
"Seo Tablo 3.1 for run conditions.
Acrosol had passod through a roughing flltor, absoluto flitor, and ollvor scroono bolore roaching this sampio polno
in the complox filter pack (position No. 3 in Fig. 3.11).
Amount of iodine in sample stream that penetratod a sllver-lined diffusion tubo and was rota ined by a charcoal.
Uned diffusion tubo and by charcoal bods, ·
"Acrosol had passed through charcoal papors in addition to components Ustod in b above, bcforo roaching this
sampic point (nurilion No. 4 in Fig. 3.11).
concentration of these two varieties of iodine. On this basis, the fraction of
iodine penetrating the silver-lined tube and collected in the charcoal-lined
tube as well as the amount of iodine collected in charcoal beds downstream from
the diffusion tubes is taken as the fraction in the penetrating form. This
division is shown in Table 3. The amount of iodine in this form, expressed as
percent of inventory, ranged from 2.5% in 9-10 to 7% in 10-7 and to 21% in
10-28. The reason for these differences is not obvious. Variations in the
heating time and in the aging time of the aerosol in the tank containing steam,
gaseous hydrocarbons, and, in one experiment, vaporized fuel particles may be
responsible for this unexplained behavior.
hindi marans en
A second method of measuring the distribution of iodine forms at different
stages in the l'ilter pack was devised to check its efficiency. Side streams
were removed from the filter pack in the manner described above, but these streams
were passed through small composite filter packs that had the same arrangement
of components as the large filter pack samples. The distribution of iodine in
the side-stream filter pack that sampled the main stream just before it passed
into the charcoal cartridges (No. 4 position in Fig. 2) is shown in the form of
block diagrams in Figs. 17 to 19 for runs 9-10, 10-7, and 10-28, respectively.
Similar data obtained in run 10-28 from the filter pack that sampled the gas
stream before passing through the charcoal papers (No. 3 position in Fig. 2) are
shown in Fig. 20. These data are summarized in Table 4. Comparison of the
distribution of iodine in the side-stream filter pack for min 10-28, before the
charcoal papers, with similar data in Table 3 shows excellent agreement, 94% in
anvratanenin
sa
kasa
ORALOWG 64.9748
ORNOWE 64.9747

1010

OD
.
.
.
.
_
.
PRESSURE
RELEASE
_
.
.
.
.
.
.
.
.
.
.
O
.
.
.
PRESSURE
RELEASE
.
.
108
ARGEN
SWEEP
..
.
.
ARSON
TRANSFER
.
.
ACTO
AIR
SWEEP
AIR
TRANSFER
131, ACTIVITY (Cs/min)
134ACTIVITY tis/min)
VITUTITTIM MINTITUTION
.
.
.
771 TUTULMUUTTUNUTRIT.
»
_
_
AMINTE
12
-
-
Wy
-
-
2
IIIIII
._.
_09
FILTER
2nd ABS
PAPER
CHARCOALS
SILVER
SCREENIS
ROUGH wille
FILTER
181 ABS
.FILTER
103 DEV
103
ROUGH &
181 ABS
SCREENS
PAPER
2nd ABS
FILTER
CHARCOAL
CARTRIDGE
3rd ABS
FILTER
CHARCOAL
FILJER
SCREENS
2 nd SILVER
3rd ABS
FILTER
. and SILVER
SCREENS
FRJER
SILVER
CHARCOALS
CARTRIDGE
Fig. 14. Distribution of Radioiodine in
Composite Filters in Run
9-10.
Fig. 15. Distribution of Radioiodine in
Composite Filters in Run 10-7.
case (Table 4) vs 90% (Table 3). It appears, therefore, that the two sampling
methods gave comparable values for the fraction of iodine in the penetrating
form in this experiment. Unfortunately, similar data were not obtained at the
No. 3 position in runs 9-10 and 10-7. On the basis of a comparison of the results
of these two experiments and those obtained in run 10-28, it appears that the
presence of vaporized particles from the VO2 meltdown enhanced the ratio of
penetrating iodine to reactive iodine by a factor of 3 to 8.
bicara...
The ratio of the amounts of iodine in the penetrating form found in the
charcoal papers and the charcoal cartridges of the larger filter pack varied
widely in these tests.
inimestesso live in
-14-
Table 4. Distribution of Iodine in Complex Filter Packs Determined by Filter
Packs in Sample Side Streams.
lodino Distribution
Run 9.109
Astar Charcoal
Papora
Run 10.90
'Altor Charcoal
Papors
Run 10-289
Aller Charcoal Boforo Charcord
Paporo
Papers
2.3
9.1
6.6
23
Gas-borne lodino in main stream
(% of Eventory)
72
26
Iodine rola ined on silver acroons
(roactive form) in side-stoam pack
(% in stream)
.
23
Iodine rota ined on charcoal papora
(mixed forms) in sido-stream pack
(% in stream)
0
.......... 42. ...
88
88
Iodine rotained in charcoal bodo
(penetrating form) in side-stream
pack (% in stream)
0.66
6.76
0.26
Amount of penetrating iodino (% of
Inventory - fraction of charcoal.
retained lodino in side stoarn X% of
inventory in main stream)
"See Table 1 for run conditions. Soo also footnotos in Tablo 3.
These values ro present only part of the penetraung lodine s inco tho charcoal pa pora rotain a fraction of tho
sodino in this form.
Thoso valuos are the total amount of penetrating iodino reaching the charcoal papers in tho complex fullor pock.
ST-
OANL OWO 66-1526
ORM -CWC 63-1927


__
_
_
_
PRESSURE
RELEASE
_
_
PRESSURE
RELEASE
ARCON
TRANSFER
d
ARGON
SWEEP
MIR
TRANSFER
1911 ACTIVITY (dismini)
1311 ACTIVITY (dis/min)
AIR
SWEEP
WW
-LA
1
WITATII
will
105
2
:
U
a
TOJ
Wii
151 Ass
FULTER
STER VILE
SILVER
SCREENS V
CHARCOAL
PAPER
2nd AGS
FHJER
300 ABS
CARTRIDGE
2nd SLVER
SCREENS
TOJ
CHARCOALA
360 FIUJER
18 ABS
FILTER
SILVER
SCREENS
PAPER V
FILTER
3rd ABS
CHARCOAL
CARTRIDGE
2nd Ass o
FILTER
2nd SILVER
SCREENS
FILTER
ROUGH
CHARCOAL
Fig. 16. Total 1311 Activity of
Filter Compact in Run 10-28.
Fig. 17. Total 1371 Activity of
Composite Filter in Position 4
After Charcoal Peper in Run 9-10.
ORXONG 65.1329
ORAL-OWG 63-1328
1.

1
PRESSURE
RELEASE

D
108
PRESSURE
RELEASE
ROON
SWEEP
:
ARGON
SWEEP
AIR
SWEEP
DO
SIR
SWEEP
1394 ACTIVITY (dis/min)
iris
· IST ACTIVITY (05/min)
>
.
ilma
V
.
1
W
.
.
.
.
.
.
.
102
ISI ABS
FILTER
SILVER
SCREENS
CHARCO:L
PAPER UL
2nd SILVER
SCREESIS
2nd beds
FRTER
CHARCCAL
CARTRIDGE
FILTE
SI:VERIIL
SCREEI:S
PAPER YU
CHARCOAL
CHARCOALS
CARTRIDGE
and LOS
SCREENS
FILTER
2nd SEVER
Ist ABS WIN
Fig. 18. Total 1311 Activity of Composite
Filter after Charcoal Papers in
Run 10-7.
Fig. 19. Total 13). I Activity of Filter 1
in Position 4 in Run 10-28.
wlo.
ORNL. ONU 65.1330

PRESSURE
RELEASE
AROON
SWEEP
AIR
..
SWEEP-
.....
.
CINVITY (dis/min)
MATW
.
.
.
.
.
.
.
.
.
il
.
be
FILTER
SILVER
SCREENS
CHARCOAL
PAPERS
and ABS
FILTER
CARTRIDGES
2nd SILVER
SCREENS
1 st ABS bell
CHARCOAL
Fig. 20. Tctal ISSI Activity of
Filter 1 in Position 3
in Run 10-28.
Behavior of Simulated Fission Products Released from Molten or Oxidized Uo,
Initial observations on the behavior of various fission products, including
radioiodine, released from a synthetically compounded V02 fuel pellet mixture were
reported earlier (3). The overpowering incentive to use simulants of real fission
products was pointed out by Roagers (6) who calculated that it would be necessary
to melt 2600 lb of UO2 irradiated to the 10,000 MWD/ton level to provide an
iodine concentration of 100 mg/m” in the CSE containment vessel (30,000 ft3).
Similarly, it would require about 117 lb of UO2 to give the same iodine concen-
tration in the NSPP (1.350 ft3). At present, only the ORNL In-Pile Fuel Melting
Facility and the Containment Mockup Facility can accomodate the radiation level
required to produce high (i.e., "realistic") concentrations of airborne fission
products. It is, therefore, imperative that attention be directed toward
obtaining useful information from.. simulant type sources in the NSPP and the CSE
(see papers 9 and 27 in these proceedings). It is necessary to compare the
behavior of fission products from irradiated fuel with that of simulated fission
products in order to give confidence in the validity of results obtained by use
of simulated fuel.
-17-
Results of Melting and Oxidizing Tests with Simulated vo, muel
Three experiments have been performed with specially prepared simulated 102
fuel. Two of the tests involved melting of stainless steel or Zircaloy-clad
specimens. In the third test, (2-24) the Zircaloy-clad fuel was heated to a
temperature below the VO2 melting point, followed by complete oxidation of the
mildly pyrophoric Zr-ZrO2-CO2 solid mixture to ZrO2-U308 powder in air as the
residue cooled below 1000°c. Total release data and the transport behavior of
the released fission products appear to correlate well with thut expected from
real irradiated fuel under similar ambient conditions (air or helium). A
comparison of the release and distribution of fission product elements obtained
in the three simulant runs with results of a fourth run performed with highly
irradiated UO2 is shown in Table 5, together with data obtuined in a similer
experiment (10-28) in which molecular iodine was released into a steam-air
atmosphere containing vaporized 102-stainless steel particles. The atmosphere
present during aging of fission products in the run with highly irradiated UO2
contained air but no steam in contrast to simulant runs where the tank contained
steam and air under pressure. Consequently, comparisons of transport behavior
may be of questionab.le value. The principal effect of the absence of steam
seemed to be a reduction in the total amount of iodine revained in the tank by
a factor of about 3. This fraction (65%) remained largely airborne and was
collected on the complex filter pack at the end of the aging period, as shown in
Table 5.
Details of the iodine distribution found in two of the simulation runs and
the high-burnup UO, experiment are given in Table 6, together with the distributioi.
of other fission products and plutonium (high-burnup fuel run only). A large
fraction of the cesium was found in the steam condensate out very little of the
tellurium, ruthenium, and strontium was "washed out" of the vessel atmosphere
by the condensing steam. Very little of the fission product activity, except in
iodine, reached the filters when steam was present and a large part of that was
retained by the roughing filter. As was mentioned above, direct comparison of
transport behavior of simulated and "real" fission products in a steam-air
atmosphere must await further experimentation.
Production of "Penetrating" Iodine During_tra Melting of Simulated High Burnup
vo, Fuel
.
The last line in Table 5 shows the amount of 'penetrating" iodine that was
estimated by means of the ratio of the "reactive" iodine on the silver-plated
diffusion tube at position 3 (see Fig. 2) following silver screen in the large
filter pack to the amount of nonreactive iodine adsorbed by the charcoal-lined
diffusion tube downstream from the silver section. In all the simulant runs
the percentage of penetrating iodine was unexpectedly low as compared to results
obtained in the tracer type run, 10-28. However, the presence of mixed hydro-
carbon gases in the tank atmosphere during this run leaves doubt concerning the
cause of the different iodine behavior. Future experiments are planned for
further comparisons of simulated and "real" fission product iodine behavior
under more nearly comparable conditions.
.
...
... Sur.
ntegrantreiben
t tar man
hi
'
-;
Table 5. Comparison of Iodine Distribution in Fission Product Simulation Experiments with that of Iodine Released
from High-Burnup Uo
Atmosphere
Run No.
Steam-air + Organics
10-28, vo, with trace
iodine
Steam-air
Air
12-9, vo, simulant 3-5, 7000 MWD/ton
Uog
Steam-Air
2:24, Zr-clad 3-25, Zr
simulant clal
oxidized
simulant
melted
5.5
15 steam, 12 air
15 stean, 12
air
15 steam,
12 air
33.7
-
56.0
27.2
25.2
15.2
57.6
72.8
8.7
48.5
57.2
89.7
14.6
1.7
Aging time of aerosol in
containment tank (hr)
Pressure (psig)
15 steam, 15 air
Iodine held in containment tank (%)
Retained on tank walls
18.3
Collected in steam condensate
Total Retained
Iodine Removed from tank
By pressure release
By argon displacement
15.7
By air sweep
1.8
Total removed
32.1
Iodine removed on test samples
0.2
Distribution of airborne iodine from tank
Retained on filters
Retained on silver or copper screens
9.1
Retained on charcoal papers
16.3
Retained in charcoal cartridges
6.6
Penetration through 1.5 in. of charcoal 0.2
Penetration through 3/4-in. of charcoal 0.5
Amount in penetrating form
21.0
.4.4
1.8
7.9
0.09
65.2
65.2
rrioso!
1.1
6.0
2.6
9.7
1.4
0.03
0.05
3.9
52.7
0.15
4.6
6.0
4.1
0.1
1.6
0.72
3.2
2.4
0.9
0.002
0.02
1.3
4.5
0.001
0.08
0.3?
0.16
0.77
0.02
0.02
0.7
0.8
-18-
Table 6. Release and Distribut-on of Fission Products from Melting of Sinulated Vo, Fucl and
High Burnup (7000 Mua/ton) UO
Location
Iodine
Cesium
3.5a 12-96 3-211€ 3-5 12-9
Release as Percent of Total in Sample
Tellurium
Ruthenium
3-28 3-5 12-9 3-28 3-5 12-9 3-27
Plutonium
3-5 12-
9
3
-5
Strontium
12-
0.4
25.2
Furnace tube
Aerosol tank
Condeni te
2.0
33.
7
56.0
2.5
8.1
71.6
6.2 3.0
13.9 15.1
43.6
26.2 2.5
17.6 46.3
44.2
0.3
6.9
0.8
0.001
0.007
27.5 0.0006 0.07
1.3 0.001 0.35
0.04
0.12
0.001 0.0006
0.12 0.001
0.02
0.01
0.04
0.0003
0.0002
0.0002
Filter pack
Roughing filter 3.4 0.5 0.1 16.5 0.8 0.02 6.2 0.1 0.01 0.0008 0.0004 0.02 0.0001 0.002
Absolute filter 0.5 0.05 0.03 0.04 0.002 0.04 0.008 0.05 0.01 0.00003 0.0002 0.003
Ag or cu
52.7 2.6 6.2 10-6
Charcoal paper 4.1 2.4 0.15
1st Charcoal 4.4 0.9 0.7
2nd Charcoal 0.07 0.02 0.02
3rd Charcoal 0.01 0.001 0.002
4th Charcoal 0.002 0.0002 0.0002
5th Charcoal 0.0005 0.0001
2nd Absolute 0.00003 0.000.1
2nd Copper
screens
0.000005 0.0001
Misc. backup
traps
0.002 0.0000!! 0.0001
Total Release 91.0 ~ 300 92.3 36.6 62.5 88.1 55.0 6.0 8.4 28.8 0.001 0.54 0.16 0.001 0.01
a. Run 3-5 was made with Yvw Mird/ton burnup 10, fuel in air.
b. Run 12-9 was made with simulated 10,000 Mwd/ton burnup UO2 fuel ina steam-air atmosphere.
c. Run 3-25 was made with simulated 10,000 Mua/ton burnup V02 fuel melted in steam and helium and with stead-air
atmosphere in the tank.
0.05
-19-
-20-
Preparation of Simulated High-Burnup vo, Fue...
The approach that was selected for preparation of simulated high-burnup
VO2 fuel was to mix the required amounts of solid f'ission product elements,
including iodine, telluriun, cesium, rutheniu, strontium or bariu, and moly-
bdenum with V02 powder and then to form the mixture into pellets. Tellurium,
rutheniu, and molybdenum were introduced as the metals aiter irradiating in the
Oak Ridge Research Rear and allowing the short-lived activities to decay. Tie
remaining elements excu_ü l'or icaine were used in the 'crl of oxiüc or cardonates
and they were mixed with suitable quantities of radioisotopes. Inactive icainc
in the form of HI was mixed with a slurry of the oxides and carbonates. The
slurry was mixed with part of the VO2 powder, dried carefully, and then mixed
thoroughly with the remainder of the UO, by use or a tumbler. A hydraulic press
was used to press -he mixture into 10-gram pellets with a thin coating of stearic
acid as a die lubr-want. Two of the pressed pellets, having a cinc: vy in the
range 60 to 30% of theoretical, were ejected from the die directly into the fuel
capsule which was then closed with a press-fit lid.
The low dersity or the cold-pressed fuel pellet may be considered
objectionable because of a greater release rate at sub-relting temperatures as
compared to release from high-density UO2 fuel. The der.sity aizierence is
considered to be of little signiiicance in fuel melting experiments. High
temperature sintering is not practical because of the vola tility of several of
the fission product elements such as iodine, cesium, and telluriw. Vibrational
compaction has been used at Hanford (see paper 27, these proceedings) to produce
simulated fuel pellets but details of the process are not presently availaole.
. ... ....oso
.
.
Conclusions on the Use of Fission Product Simulants
...
.
..
Further comparisons of fission product release and transport from real and
simulated fuel materials are highly desirable, but, on the basis of available
information, it seems practical to simulate high burnup UO2 fuel.
.,
Behavior of Pure Methyl Iodide in the CMF
...
...
-.
.
.ir
Since it was felt that many different and definitive questions could come
answered by the direct observation of the behavior of pure radioactivity-106c
methyl iodiae in the CMF, an experimental demonstration was carried out uncer
conditions approximately duplicating those of the current simulated fuel meltdown
tests.
..
them.co do time. Humor »
invite
met
Labeled methyl iodide was prepared by isotopic exchange. In earlier
experiments, it was demonstrated that an efficient exchange could be conducted
between accurately measured small amounts of inactive methyl iodide and the
essentially weightless radioiodine (Nal311, ~ 20 micrograms per curie) dissolved
in ethyl alcohol. In this particular case, a yield of 500? oi the 1.311 as methyl
iodide vas obtained after six days contact time between 100 millicuries of Nat^bI
and about 800 micrograms of methyl iodide. Since all of the mass of methyl iodide
is recovered with that part becoming isotopically labeled, the lirial speciiic
activity of the product is readily established. For the purposes of the C.F,
niet
g
no
this
.
-21-
poroxinitely 50 millicuries of iodine as thus exchanged and then extracted
Wichti-accine Iron which it was carefully distilled by heliw purging at about
3500. small amount of vaporized n--decare vas trapped in a con-cooled bath and
tric bulk of the methyl iodiảe was retained in a cmall liquid nitrogen-cooled
cuirless stcel gas holder. The double valvei gas holcer was then fitted to the
C.crd i heliu. purge line was attached to aid in displacing the radioactive
product into the pressurized vessel.
i
fir By Coconut Charcoal =
CO!:) 71::on of ethy? "cide Retention Iron c
Diiii'crcnt widities
In order to conduct a complete test or methyl iodide response to a simulated
mitdown environment, including both steam and vaporized VO2-Í'uei componerts, a
Pue? mclting experiment was conducted with unirradiated Zr-2 clad UO2 while the
1511-? scled methyl iodide (400 micrograms) was admitted to the pressurized tank
ct 15 los gauge of steam and 15 lbs gauge oz' air at 120°c. The normal procedure
of discontinuing artiricial heating (by stoppind the Ilow O scene into the tark)
and periitting spontaneous cooling of the tank and its conter.is was followed.
GPS suples were withdrawn at intervals to follow changes in aircorne iodine
concentration and successive samples oſ the stearcondensate were also removea.
These were analyzed by selective extraction to supply information on the extent
of water solubility and hydrolysis of methyl iodide.
At the end of the usual 5-hr aging period, the pressurized tank atmosphere,
Süturated with water vapor at about 30°C, was vented through duplicate filter
pücks of the types shown in Fig. 2. However, one of the packs was heated to
about 70°C while the other was lei't unheated. Approximately 4-in thickness of
coconut charcoal was tested in each half of the stream and this was backed up by
ö in. of 5% morpholine-inpregnated coal-based charcoal (BPL).
It was expected that some breakthrough of methyl ioa ide might occur,
especially on the unheated filter pack, and that the morpholine-impregnated
coal-based charcoal might be exposed to reasonable activity levels, thereby
üilording i test of its value for use in backing up ordinary charcoal beas.
Results
The results of the test are summarized in Table 7. It is clear that no
significant changes, such as deposition, adsozption or decomposition, occured in
che methyl iodide at 120°C in steam and that very little (0.2) was dissolved
in the condensate. Only 15% OI' the iodine in the condensate was round to be
aydrolyzed or otherwise inextractaole with CC14 from a solution to which a reducing
agent (sodiun bisulfite) had been added. Thus, 99.8% remained airborne and was
displaced through the charcoal filter beds by the pressuir letàown, argon
displacement, and air sweep cycles.
The absorption profile through the charcoal (Fig. 21) was surprisingly
zound to be exponential and, at first glance, this raised some question about üze
reported effect or high humidity on the retention of methyl iodide by coconut
charcoal. Sone after-thought and simple calculations, however, showed that only
-22-
Table 7. Distribution of Iodine Activity from Tagged Methyl Iodide Released in
the Cir
Location of Activity
Percent Total Activity
Retained on tank walls
0.095
0.oosa
Collected in steam condensate
Total retention
0.188
zodine removed from tank
By pressure release
51.5
By argon displacement
48.2
0.08
99.8
By air sweep
Total renved, "airborne"
"Airborne" I, from tank on filterso
Ag/Cu screens
Charcoal papers
0.004
0.028
21.4
Charcoal cartridges
73.04
Penetration through 3/4" charcoal (~ 1 hr run)
2.21
99.9
Penetrating iodine
a.
The iodine collected in the steam condensate was 85% CCl4 extractable in the
presence of reducing agents. Assumed to be 85% as organic iodide.
b.
Total on rough and first absolute filters.
T
.
+-
-23-
the first of the five charcoal cartridges was exposed to any significant
amount of water vapor and even this one was apparently not saturated. A test
run later at a similar humidity showed that the first cartridge gained only about
10% in weight while about 30% is required to saturate charcoül at this temperature.
The succeeding cartridges retained a little more than half as much water as the
first cartridge. Thus, the dehydration effect of the charcoal prevented a
determination of its iodine-retention ability in the preser.ce of humid air.
Since the high retention behavior of the coconut charcoal ::: uvented much
penetration to the morpholine-impregnated backup charcoal (Fig. 22), nothing was
learned in this experiment about its retention of methyl iodide in the presence
of high humidity. There were some interesting variations between the performance
of heated and unheated filter packs, especially in regard to retention of methyl
iodide by the charcoa" papers. This difference is apparently the best indication
we obtained of the ecoct of saturation with water vapor. In the unheated pack
the charcoal papers retained only about 0.1% of the methyl iodide wise in the
heated unit the retention was almost 40% in six layers which provided the
approximate equivalent of a 1/1o-in.-thick charcoal bed. The overall distribution
throughout the filter pack can best be shown by reference to tre block diagrams,
Figs. 23 and 24, in which the heated and unheated streams are compared. It was
also of interest that while the total amount remained small, the heated silver
retained almost in times as much iodine as did the unheated silver. This perhaps
may be interpreted as an indication of partial decomposition of methyl iodide on
the silver at the elevated temperature.
In continuing this program, the effect of saturation of the charcoal with
water vapor will be considered along with a study oi the effect of heating the
charcoal ked to lower the humidity. The substitution of impregnated charcoals,
both coal-base and coconut, will be tested at varying loadings of methyl iodide.
.
.
--,
---
Livi.
-*,
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ORUL - AEC - OFFICIAL
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References
Orin
1.
C. J. Barton, G. W. Parker, G. E. Creek, and W. J. Martin, "Fission Product
Transport Evaluation", ORNL-3483, p. 33, Septeraber 1963.
G. W. Parker, G. E. Creek, W. J. Martin, R. A. Lorenz and C. J. Barton,
"Properties of Fission Product Aerosols Produced by Overheated Reactor
Fuels", ORNL-3547, p. 3, March 1964.
3.
G. W. Parker, R. A. Lorenz, G. E. Creek, J. G. Wilhelm, W. J. Martin, and
C. J. Barton, "Release and Transport or voz Fission Products in the Confine-
ment Mockup Facility", ORNL-3691, p. 3, November 1964.
4.
G. W. Parker, W. J. Martin, G. E. Creek, and C. J. Barton, "Behavior of
Radioiodine in the Containment Mockup Facility", ORNL-3776, p. 57, March
1965.
in
6.
M. J. Bradley and L. M. Ferris, Inorg. Chem. 3, 730 (1964).
A. J. Horton and J. L. Botts, Nucl. Sci. Eng. 18, 97 (1964).
A. C. Chamberlain et al., "Report of Aerosol Group, Part I. Physical
Chemistry of Iodine and Removal of Iodine from Gas Streams ", AERE-R-4286,
April 1963; J. Nucl. Energy: Part A and B (Reactor Science and Technology)
17, 519 (1963).
e ²
.
.
.
ORH-AEC - OFFICIAL
END
+
-
-
DATE FILMED
18 / 30 /65





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