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11
MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS -1963
ORNU-P-1416
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''JUT an PONE'
Ics211 mN_50
OXIDATION OF FUELED AND UNFUELED
GRAPHITE SPHERES BY STEAM*
J. L. Rutherford, J. P. Blakely and L. G. Overholser
Reactor Chemistry Division
Oak Ridge National Laboratory
Oak Ridge, Tennessee

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Until
SECTION
RELEASED FOR ANNOUNCEMENT
IN NUCLEAR SCIENCE ABSTRACTS
-LEGAL NOTICE
dire
s i
Tw, report ms properest u na account of Government sponsored mrk. Nellbor ibo Valled
Halos, bor us Coawsoba, dor Lay period acting oo bobull of the Coamission:
A. Nakas ay nrriaty or repertuatation, expressed or implied, mille raspect to IX icon-
racy, completeness, or une hudour of the informados coatalood lo talo report, or that we use
of any lalor mallon, appuntu, melbod, or procui discloseu la we report may not lalringe
printly omod ribus; or
B. Aswmer day labiuues wild rospect us be an of, or for damage resulting from the
On of Lay lalor matica, appuntu, method, or procon discloud lo this report,
Ao used to the above, "person actory oo belll of the Coomoto" includes way ..
pioji or coatractor of the Commission, or employee of such contractor, to the extent that
locà employing or contractor of the Commission, or employee of such coolractor preparı,
diseminarer, or pronides accusi may information puranat to do employant or coolrict
with the Commonsloo, or No employmeat with such contractor.
1... ca
,--
-
*Research sponsored by U.S. Atomic Energy
Commission under contract with the Union Carbide
Corporation.
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ABSTRACT
The oxidation of varinus fueled and unfueled graphite
spheres (1.5-in. and 2.36-in. diameter) by steam was de-
termined at 800, 900, and 1000°c using a partial pressure
of ~730 mm (Hg) and flow rates of 600 to 1200 cm3 /min (STP)
of steam. The fueled spheres contained pyrolytic-carbon
coated UC, or (U, Th)C, particles dispersed in graphite
matrices; the unfue led spheres were machined from ATJ and
Speer Moderator-2 grades of graphite. Reaction rates were
determined from weight changes and analyses of the effluent
gases. The effect of burnoff on the reaction rate was found
to be quite pronounced. The marked differences in the co to
CO, ratios observed in the effluent gases appear to be
associated with both the degree of burnoff and purity of
the graphite. BET surface area and mercury porosimetry data
obtained for several oxidized unfueled spheres are included.
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OXIDATION OF FUELED AND UNFUELED
GRAPHITE SPHERES BY STEAM
J. L. Rutherford, J. P. Blakely and L. G. Overholser
1.
INTRODUCTION
The studies described in this paper deal in part with
the oxidation of fueled graphite spheres by a relatively
high partial pressure of steam, such as that which might
result from a failure in a steam generator. Oxidation of
the fuel body by steam could cause mechanical failure of
the fuel body, as well as failure of the pyrolytic-carbon
coatings of the fuel particles. The latter effect would
produce a rapid release of fission products. The hydrogen
resulting from the steam-carbon reaction might be hazardous;
a serious explosion could occur if air also were present as
would be the case if both the main coolant circuit and the
steam generator failed.
.
..
Numerous experimental studies of the steam carbon
system have been made. Most of the results have been
erita sini s.r.o. -
...
c
:
,': il..
summarized recently 1, 2) and will not be considered further.
None of these studies is directly applicable to the problem
at hand mainly due to differences in the composition and
geometry of the materials.
Experimental studies were performed to establish the
reaction rates of various lots of fueled graphite spheres
with steam at a partial pressure of ~730 mm (Hg) and tempera-
tures of 800 to 1000°c. Similar studies were performed with
unfue led graphite spheres to provide some basis for comparing
well graphitized material with the forms of carbon present
in the fueled spheres. Probable use of an outer shell of
machined graphite for the fuel element also prompted the
investigation of unfueled graphites.
EXPERIMENTAL
Spheres machined from ATJ and Speer Moderator-2 grades
of graphite were used for the unfueled graphite studies.
.
.
AT3 is a molded, fine-grain graphite having an apparent
density of ~1.8 g/cm3 and an ash content of ~1000 ppm
(mainly calcium). Speer Mod-2 is an extruded graphite having
an apparent density of ~1.7 g/cm3 and an ash content of
<20 ppm. The 1.5-in. diameter ATJ and Speer Mod-2 spheres :
weighed. 52 and 50 g, respectively. The spheres were used
without any pretreatment.
Various lots of 1.5-in. diameter fueled graphite spheres
manufactured by General Atomic Division, General Dynamics
Corp. (GA), Minnesota Mining and Manufacturing Co. (3M),
Speer Carbuu Co. (SCC), and Carbon Products Division, Union :
Carbide Corp. (NCF) were used in the fueled graphite studies. :
.
. .
.
.
.
.
.
-
..
...
.
...
..
.
.
..
..
.
lin #rater.
They contained pyrolytic-carbon coated (U,Th)Cz particles
ü
dispersed in graphite matrices and were prepared by a molding
process. Some of the fueled spheres were prepared with molded

unfueled shells, oihers had no such shell (see Table 2).
The GA and 3M fueled sijheres had fuel loadings of 3 g of U
and 2 g of Th, the scc and NCF spheres 1.96 g of U and 1.2 8
of Th. These fueled spheres ranged in weight from 51 to 56 g.
Fueled 2.36-in. diameter spheres prepared by Carbon Product
Division also were studied. These spheres had a 1.0 cm shell
of ATJ graphite surrounding the core which contained pyrolytic-
carbon coated UC, particles supported in a graphite matrix.
Tests were made at 800, 900, and 1000°c using a partial
pressure of steam of ~730 mm (Hg). The 1.5-in. diameter
spheres were supported in a 2-in. diameter mullite tube by a
bed of a.lumina pebbles which also served as a preheater for
,
the steam. Steam was generated by an electrically heated
boiler, passed upward through the mullite tube at a flow rate :
of 600 cm3 /min (STP) and condensed. Flow rates were es-
tablished from the volume of condensate. Helium was bled
into the steam line at ~15 cm3/min (STP) to facilitate
collection of gas samples at low reaction rates. The gas
leaving the condenser was dried prior to venting through a
manifold equipped for gas sampling. Gas samples were analyzed
hy the Analytical Service Group using a gas chromatograph and,
in a few cases, a mass spectrometer. Oxidation studies of
2.36-in. diameter spheres were performed similarly using a
3-in. diameter mullite tube and a flow rate of 1200 cm3/min
· (STP). BET surface areas were determined by nitrogen
adsorption.
. .
The reaction rates reported were obtained from weight
:
..
.
.
.
-
.
.
...
.
changes, unless otherwise indicated, and are average rates
for periods ranging from 1 to 5 hr. No continuous record of
the weight was obtained; weighings were made before and after
a run. Rates calculated from the composition and flow rate
of erfluent gases were in good agreement with those obtained
from weight changes in most cases. Reaction rates were
obtained for the unfueled spheres over a wide range of burnoft.
The 1.5-in. fueled spheres were oxidized only to low burnoffs
“because they were to be tested subsequently for changes in
mechanical strength resulting from limited oxidation.
....
.
1
:-:
:!!!
3. RESULTS AND DISCUSSION
3.1 Oxidatio of Unfueled Graphite Spheres
The effects of temperature and burnoff on the reactivity
-::-
-
.):
memang seoranas not withione
of the unfueled 1.5-in. diameter graphite spheres are shown
in Fig. 1. Activation energies determined from the slopes of
the plots are ~60 kcal/mole and appear to be nearly independent
of burnoff. The slight increase with burnoff in the case of
Speer Mod-2 graphite may or may not be significant. Data
obtained at various burnoffs at 800, 900, and 1000°c are
detailed in Figs. 2-4, respectively. As expected, the re-
action rates increased rapidly with increasing burnoff at i
low burnoffs. The reaction rates for Speer Mod-2 graphite
increased slowly at burnoffs in excess of ~5 wt %, whezzas
those for ATJ graphite continued to increase rapidly over ...
ini
thing

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.
in the
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iii..m;
.
.
.
.
:
, the entire range of burnoffs studied. Rates measured at
1000°c for ATJ graphite (Fig. 4) show that the reaction rate
is a linear function of burnoff over the entire range of
burnoffs examined.
The similarity between the curves given in Figs. 2-4
for the reaction rate and the surface area for the two
graphites prompted an examination of the relationship between
the reaction rate and the BET surface area.
The plots shown
in Fig. 5 indicate that the specific reaction rates based on
BET surface areas are about equal at 900 and 1000°C. This
would suggest that if the impurities present in the ATJ
graphite make it more reactive than the purer Speer Mod-2
graphite they must do so by increasing the rate of develop-
ment of the surface during oxidation.
The curves for the co/CO2 ratios given in Figs. 2-4
have been replotted in Fig. 6 to show the marked differences
in this ratio. It is apparent that this ratio is affected
by type of graphite and degree of burnoff as well as tempera-
ture. The most plausible explanation for the smaller ratios
found in the effluent gases from the ATJ graphite is that
the impurities present catalyzed the reaction CO+H2O
CO2+Hz. As will be noted later, the size of the sphere
also influenced the ratio. The increases in co/co, ratio
with increasing burnoff particularly at the low burnoffs are
difficult to explain. An increase in the ratio indicates
either that more of the carbon is appearing as co in the
primary reaction products or that less Co is converted to
+
-
=
CO2 by the water-gas shift reaction.
It is difficult to
i
-
-
-
visualize any changes in the properties of the graphites
that might occur during the early stages of oxidation which
could have such a marked effect on the co/C0, ratio.
Equilibrium quotients, for the reaction co+H,0 = CO2+Hz,
calculated from the composition of the effluent gases from
the 1.5-in. diameter spheres are smaller than the equilibrium
constants in all cases. In many instances the values are one
to two orders of magnitude less than the equilibrium constants.
• The only conditions at which equilibrium was attained was at
1000°c using 2.36-in. diameter ATJ spheres. Values for the -
09
1301','12
CO/CO2 ratio found in the effluent gases from these larger
spheres were about an order of magnitude less than those
found for the smaller ATJ spheres. The reaction rates at
1000°c were about the same for the two sizes of ATJ spheres
but the larger spheres gave activation energies of 45 to
50 kcal/mole compared to ~60 kcal/mole for the smaller spheres.
. .
.
.
.
.
.
-
-
...
Thus, the sphere size affects both the composition of the
effluent gases and the activation energy. ..
Surface area measurements were made on the 1.5-in.
diameter unfueled spheres after being oxidized to various
degrees by steam. Most of the carbon removal occurred at
1000°c. The surface area of the oxidized sphere was measured
as well as portions from the outer and central regions of the
sphere. Data are listed in Table 1. These data indicate
that the surface area of ATJ graphite increases more rapidly
-
-
-
- .
-
-
----
-
-
.
...
...
•
. -
non sarana mensahe nici in un
01.::::: A:1:"!
stes
le
· with oxidation than does that of Speer Mod-2 graphite. They
also show that the oxidation of Speer Mod-2 graphite occurs
more uniformly throughout the sphere at the lower burnoffs
than does that of ATJ graphite.
Mercury porosimetry data obtained from specimens used
for the surface area measurements (Table 1) are shown ’in
Figs. 7-10. ATJ graphite cut from the central region of
oxidized spheres (Fig. 7) shows small increases in accessible
volume in pores with radii of ~3 H and <0.05 Ho Samples cut
from the outer regions of these same spheres (Fig. 8) have
larger accessible volumes confirming the nonuniform oxidation
of the sphere. Extensive oxidation increased the accessible
volume in pores with radii of ~3 u and <0.54. Data in Figs.
9 and 10 show that the central regions of the oxidized
Speer Mod-2 graphite spheres were attacked nearly as severely
as the outer regions. This is in agreement with the surface
area data. Light oxidation (6 wt % burnoff) increased the
accessible pore volume very little; oxidation to ~40 wt %
burnoff resulted in a twofold increase. The increase in
volume was largely concentrated in pores with radii 0.1 to
15 H.
3.2 Oxidation of Fueled Graphite Spheres
Reaction rates obtained for various lots of 1.5-in.
diameter fueled spheres are plotted as a function of tempera-
ture in Fig. 11. Most of the values were obtained at burnoffs
of less than 5 wt %. Values are given for the scc spheres
10
..
:
.
.
only at 900°C because of early failure at 1000°c and ab-
normally large weight losses at 800°c, the latter due to
excessive outgassing. The maximum variation in reaction
rates is about a factor v2 5 if lot GA-S5 is excluded. This
lot was impregnated and therefore not strictly comparable to
the other lots. The reaction rates given in Fig. 11 are in
fair ag reement with those found for the unfueled spheres
(Fig. 1) as well as with rates reported 4-6 for other grades
of graphite. The slopes of the plots given in Fig. 11.
correspond to activation energies of ~60 kcal/mol, compa-
rable to that found for the unfueled spheres. The change *
in reactivity with burnoff produces some uncertainties in
:
such comparisons.
Reaction rates obtained at 900°C for most of the 1.5-in.
.............
altres costeshikaran....................
diameter fueled spheres examined are listed in Table 2.
Hydrogen production rates and co/CO2 ratios also are in-
cluded. The data indicate that the presence of unfueled
shells had no significant effect on the reaction rates.
A11 lots of SCC spheres were more reactive at 900°c than
any of the other lots studied and most failed at burnoffs
of 3 to 5 wt%. The high incidence of failure was due, only
. in part, to higher reaction rates since fueled spheres rom
GA and 3M lots remained intact at comparable and larger burn-
offs. This suggests that the attack of the SCC spheres was
more strongly concentrated on the residual binder material
than was the attack of the other lots of fueled spheres.
Ciri iyi.

sana watu nanti con menu
bwa
11
Microscopic examination and nitric acid leach of the materials
remaining after failure of the fueled spheres showed that no
serious attack of the pyrolytic-carbon coatings on the fuel
particles occurred.
The effects of temperature and burnoff on the reactivity
of fueled 2.36-in. diameter spheres with steam are shown in
Figs. 12 and 13. The essentially linear relationship between
the reaction rates at 1000°c and degree of burnoff and a non-
linear relationship at 900°C are in agreement with data found
for 1.5-in. diameter spheres of ATJ graphite (Figs. 3 and 4).
The slopes of the plots in Fig. 12 correspond to activation
energies of ~50 kcal/mole at all three degrees of burnoff,
indicating that the activation energy is nearly independent
of burnoff over a wide range of oxidation. The value of ~50 :
kcal/mole given for the activation energy is in fair agreement
with that found for 2.36-in. diameter ATJ spheres, but is
significantly less than the ~60 kcal/mole measured for 1.5-in.
diameter spheres of ATJ and Speer Mod-2 graphites as well as
for the 1.5-in. diameter fueled spheres. Apparently, the
sphere diameter influences the activation energy under the
experimental conditions employed. The co/CO2 ratios in the
effluent gases obtained from the reaction at 1000°c ranged
from 0.3 to 0.5 with no consistent effect of burnoff evident.
These values are somewhat larger than those found in the case.
of 2.36-in. diameter ATJ spheres. No serious attack of the
fuei particles was observed despite extensive oxidation of
the fueled spheres.
12
--.--.
---.
REFERENCES
-
.
.
..-..-am
.
..
......
.
.
...
.
-
1. Walker P. L. Jr., Rusinko F. Jr. and Austin L. G., .
Advances in Catalysis 11, 133 (1959).
Clark T. J., Woodley R. E. and de Halas D. R., "Gas-
Graphite Systems" in Nuclear Graphite, R. E. Nightingale
(Ed.) pp 387-444, Academic Press, Inc., New York, 1962. ..
3. Mayers M. A., J. Am. Chem. Soc. 56 1879 (1934).
4. Johnstone H. F., Chen C. y. and Scott D. s., Ind. Eng.
Chem. 44, 1564 (1952).
5. Pilcher J. M., Walker P. L. Jr. and Wright C. C.,
ibid. 47, 1742 (1955).
Abel W. T. and Holden J., The Suspended Specimen Method
for Determining the Rate or the Steam-Carbon Reaction,
U. S. Bur. Mines Rept. Invest. No. 6000 (1962). ·
-
-
-
-
-
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1:10.7YFIY

13
Table 1. Effect of Oxidation by Steam on the Surface Area
of 1.5-in. Diam. Unfueled Graphite Spheres
Grade of
Graphite
Burnoff
(wt %)
- Surface Area (m2/g)“
Whole Outer
Central
Sphere Region Region
ATJ
0.11
7.0
4.7
6.2
1.0
22
8.1
14.0
11.8
11.6
Sp:18: Mod-2
0.22
2.4
34
4.4
4.5
45
3.7
Determined by BET method using nitrogen.
14
• Table 2. Reactivity of Various 1.5-in. Diam. Fuoled Graphite
Spheres with Steam at 900°C (partial pressure of steam
~730 mm, flow rate ~600 cm3/min)
Sphere
Designation
Thickness of
Unfueled
Shell
(in.)
Reaction
Rate
(mg/g.hr)
Hydrogen
Produced
(cm3 /g.hr)
C0/CO2 in
Effluent
Gas
NCF-S1-4D
- 1.7
5.9
2.9
NCF-S3-R1
4.7.
2.4
3M-S2-23
o
0.5
!!;: ..IN
3M-S3-15
2.4
14
m. ,'. "O
3M-S3-18
1/16
1/16
1/8
1.0
0.6
1/8
1/16
4.8
.
5.7
3.5
5.6
3M-S6-18
3M-S6-19
SCC-S5-3
SCC-S5-7
SCC-S6-18
SCC-S7-11
SCC-S7-13
SCC-S8-13
SCC-58-15
GA-S3-6
GA-S3-11
GA-S3-14
GA-S4-9
GA-S4-13
5.3
1.5
0.4
0.1
1.2
1.2
7.5
7.7
5.8
7.7
0.3
1.0
1/4
1/4
0.87
4.1
15
Table 2 (continued)
Sphere
Designation
Thickness of
Unfueled
Shell
(in.)
Reaction (1)
Rate
(mg/g.hr)
Hydrogen
Produced
(cm3 /g.hr)
co/CO2 in
Effluent
Gas
0
0.25
0.5
GA-S5-11 (2)
GA-85-17 (2)
GA-S5-18 (2)
0.28
0.7
0
0.09(3)
0.3
(1) Rates
Rates given are for burnoffs ranging from 0.5 to 1.5%.
(2) Impregnated.
This sphere had been degassed at 1000°C prior to oxidation.
The low rate is due at least in part to a burnoff of
<0.05%.
FIGURE CAPTIONS
Fig. 1. Effects of Temperature and Burnoff on the
Reactivity of 1.5-in. Diam. Unfueled Spheres.
Fig. 2. Effect of Burnoff on Reaction Rates and co/CO2.
Ratios of 1.5-in. Diam. Unfueled Spheres at
800°c.
!..?" ::IN
oldu.UI.
Fig. 3. Effect of Burnoff on Reaction Rates and co/CO,
Ratios of 1.5-in. Diam. Unfueled Spheres at
900°c.
Fig. 4. Effect of Burnoff on Reaction Rates, Surface
Areas and co/CO, Ratios of 1.5-in. Diam.
Unfueled Spheres at 1000°c.
Fig. 5. Relationship Between Reaction Rate and Surface
Area for 1.5-in. Diam. Unfueled Spheres.
Fig. 6. Dependence of co/CO, Ratio on 'Burnoff for
1.5-in. Diam. Unfueled Spheres.
Fig. 7. Cumulative Pore Volumes of Specimens Cut From
Central Region of Oxidized 1.5-1n. Diam. ATJ
Graphite Spheres.
Fig. 8. Cumulative Pore Volumes of Specimens Cut From
Outer Region of Oxidized 1.5-in. Diam. ATJ
- ..
Graphite Spheres.
-
-
- -
-
.: Fig. 9. Cumulative Pore Volumes of Specimens Cut From
Central Region of Oxidized 1.5-in. Diam. .
Speer Mod-2 Graphite Spheres.
e
int
...
.
..
este
Figure Captions (continued)
Fig. 10.
Cumulative Pore Volumes of Specimens Cut From
Outer Region of Oxidized 1.5-in. Diam. Speer
Mod-2 Graphite Spheres.
Fig. 11. Effect of Temperature on the Reactivity of
Various 1.5-in. Diam. Fueled Spheres.
Fig. 12. Effects of Temperature and Burnoff on the
Reactivity of 2.36-in. Diam. Fueled Spheres.
Fig. 13.
Relationship Between the Reaction Rate and
.....
Burnoff for 2.36-in. Diam. Fueled Spheres.
wa
ambal kan
S
-
-
-
UNCLASSIFIED
ORNL-DWG 64-11214
1000
950
800
TEMPERATURE (°C)
900 850
TTTTTT
• ATJ 25 % BURNOFF
A ATJ. 10 % BURNOFF
I ATJ 5 % BURNOFF

20 Le
REACTION RATE (
O SPEER MOD-2 25 % BURNOFF
0.25 A SPEER MOD-2 10 % BURNOFF
O SPEER MOD-2 5% BURNOFF
conceito
williyi
iene
090
t
7.8
8.0
8.2
8.6
8.8
9.0
9.2
9.4
cosisi
10,000/T (OK)
8.4
10
..... .--. ........ . ..............
Fig. 1. Effects of Temperature and Burnoff on
the Reactivity of 1.5-in. Diam. Unfueled Silicres.
- booom
.
...
...
.
.....
......
..
.......
.
........
.
. .
.
.
....
.
.
.
-'
-
........
...
REACTION RATE (mg/g.hr)
-
-
. - -
-
-
-
-
08

0
... -
-
-
...
-
5
A A ATJ
0 • SPEER MOD-2
10
RATE
-RATE
15
BURNOFF (wt %)
20
CO/CO2
SURFACE AREA
-C0/C02H
-
-
25
-
-
---
------
30
AREA
SURFACE
ORNL-OWG 64-11217
UNCLASSIFIED
35
14
CO/Co2
SURFACE AREA (m2/g)
Fig. 2. Effect of Burnoff on Reaction Rates and
CO/CO, Ratios of 1.5-in. Diam. Unfueled Spheres at
800°C.
.:
:
.
...............
..... -
UNCLASSIFIED
ORNL-DWG 64-11216

-
--
--
-
- .
-
4. ATJ
_ 0. SPEER MOD-21
-
-
- ...
-
-
...
-
RATE
SURFACE
AREA
REACTION RATE (mg/g.hr)
SURFACE AREA (m2/g)
co/CO2
OT RATE
SURFACE AREA
co/CO2
0
5
10
25
30
35
15 20
BURNOFF (w+ %)
-... - ...........
.
...
..
...
..
. ....
.
......
.....
..
.....
.
.................
.
..
:
Fig. 3.' Effect of Burnoff on Reaction Rates :
and CO/.CO2 Ratios of 1.5-in. Diam. Unfúeled Spheres
at 900°C.
REACTION RATE (mg/g • hr)
25
08

o
5
AA ATJ
o• SPEER MOD-2
10
RATE
15
BURNOFF (wt %)
20 25
SURFACE AREA -
co/00,-
co/co2 —
RATE
30
AREA
SURFACE
35
ORNL-DWG 64–11218
UNCLASSIFIED
40
co/co,
SURFACE AREA (m2/g)
Fig. 4. Effect of Burnoff on Reaction Rates,
Surface Areas and co/CO2 Ratios of 1.5-in. Diam
Unfueled Spieres at 1000°C.
.....
.
...
-
-
•
ORNL-DWG 65-500

O O SPEER MOD-2
AS ATJ
.
18
1000°C
REACTION RATE (mg/g.hr)
1000°C
900°C
.
...
i
fetin
: :>.
900°C
O Lo
10
8
SURFACE AREA (m2/g)
.
.
. .
. .
.
.
..
...
.....
Fig. 5. Relationship Between Reaction Rate and
Surface Area for 1.5-in. Diam. Unfueled sphorun.
...
--
..
.•
•
....--.-...
.--.--. --- --- -..-.co.
ا
UNCLASSIFIED
ORNL-DWG 64-14215

ه
oo • SPEER MOD--2
AAO ATJ
ح
900 °C
م
800 °C
ل
co/CO2
م
ل
-1000 °C
900 °C
م
1000 °C
د
800 °C
0
o
5
10
15 20
BURNOFF (wt %)
25
30
35
Fig. 6. Dependence of co/CO2 Ratio on Burnoff
for 1.5-in. Diam. Unfueled Spheres. :
....
....... .
.
.
. .

UNCLASSIFIED
ORNL-DWG 64-10845
PORE RADIUS (microns)
50 10
. 9
0.1
0.01
MITTTTTTTTTTTTTTTTTTTTTTTTT
0.20 PTTITUL
0.16
1 UNOXIDIZED
2 7 wt % BURNOFF
3 8 wł % BURNOFF
| 4 22 wt % BURNOFF
F5 38 wt% BURNOFF
PENETRATION (cm3.9-)
14 5
3
·
10
10,000
100
1000
ABSOLUTE PRESSURE (psi)
Fig. 7. Cumulative Pore Volumes of Specimens Cut From Central
Region of Oxidized 1.5-in. Diam. ATJ Graphite Spheres.
UNCLASSIFIED
ORNL-DWG 64-10846
PORE RADIUS ( microns )
0.1
10
0.01

0.28
TTTTTTTTTT
1 UNOXIDIZED
2 7 wt % BURNOFF
3 8 wt% BURNOFF
4 22 wt % BURNOFF
5 38 wt % BURNOFF
E
PENETRATION (cm3.9-1)
3
10
10,000
100
1000
ABSOLUTE PRESSURE ( psi)
Fig. 8. Cumulative Pore Volumes of Specimens
Cut From Outer Region of Oxidized 1.5-in. Diam. ATJ
Graphite Spheres.
. .
.
.
.
.
.
....
•"•--..--
...-
.-
......
. .
V
...
......
..
...
.
..
...
UNCLASSIFIED
ORNL-DWG 64-10844
PORE RADIUS (microns)
0.04
TT IIIITTTTT TITTTTT

10
0.1
- 50
0.24 MITT
W
!
I
À UNOXIDIZED
2 6 wt % BURNOFF
3 34 wt % BURNOFF
|--4 44 wt % BURNOFF
PENETRATION (cm3.g-1).
-
3
-
-
0.04
10
10
10,000
100 1000
ABSOLUTE PRESSURE (psi)
.
.
..
.os
..
Fig. 9. Cumulative Pore Volumes of Specimens Cut From Central
Region of Oxidized 1.5-in. Diam. Speer Mod-2 Graphite Spheres.
UNCLASSIFIED
ORNL-DWG 64-10843
10
PORE RADIUS (microns)
0.1
0.01

-
0.32
!
-
-
-
-
--
-
--
-
-
-
-
-.
0.28
1 UNOXIDIZED
2 6 wt % BURNOFF
1 3 34 wt % BURNOFF
L4 44 wt % BURNOFF
PENETRATION (cm3.99)
10,000
100
1000
ABSOLUTE PRESSURE (psi)
Fig. 10. Cumulative Pore. Volumes of Specimens
Cut From Outer Region of Oxidized 1.5-in. Diam. Speer
Mod-2 Graphite Spheres.
UNCLASSIFIED
ORNL - DWG 63-6754
TEMPERATURE (°C)
900
1000
950
850
800

0 3M-53-15
- • 3M-52-23
A GA-S3-6
D NCF - 53-R1
I GA -S4-9
O GA-55-11
A SCC-57-11
SCC-58-43
A SCC-55-3
REACTION RATE ( mg/g.hr)
:
0.
ama..
7.8
8.2
8.6
9.0
.cam
10,000/(OK)
Fig. 11. Effect of Temperature on the Reactivity **
of Various 1.5-in. Diam. Fueled Spheres.
.
..
.
UNCLASSIFIED
ORNL-DWG 64-9541
TEMPERATURE (°C)
900
850
800
1000
950

o 25% BURNOFF
• 10% BURNOFF
Lo 5% BURNOFF
REACTION RATE (mg/9.hr)
_
-
7.8
8.0
8.2
9.0
9.2
9.4
8.4 8.6 8.8
10,000/ (OK) .
100
'
'
.
Fig. 12, Effects of Temperature and Burnoff on
the Reactivity of 2.36-in. Diam. Fueled Spheres.
....-
..
-
...
.
...
..
..... ...
.. .
.
.
.
.
.
UNCLASSIFIED
ORNL-OWG 64-9542

REACTION RATE (mg/g.hr)
1000°C
900°C
-
-
2
REACTION RATE (mg/g.hr)
5
10
25
30
35
15 20
BURNOFF (wt%)
·Fig. 13. Relationship Between the Reaction Rate and
Burnoff for 2.36-in. Diam. Fueled Spheres..
.
.
-
---- ---
..
6/27 / 66
DATE FILMED
END
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