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.
MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS - 1963
CORNU P-1194 .
van
Art
CFSTI PRICES
· APR Ź 1965
H.C. $ 3.00.; MM, 50 MASTER
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lladamoramos protagoni, mint
mindenkortit;*
IRRADIATION OF SINTERED BERYLLIUM OXIDE TO HIGH FAST-NEUTRON, DOSES AT 110, 650,
AND 1100°C*
G. W. Keilholtz
J. E. Lee, Jr.
R. E. Moore
Reactor Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee


"NU INFORMEDLIGASTEAS
DIST on other to IMA Images
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Inim
RELEASED FOR ANNOUNCEMENT.
Commons POV FIBRANT SAD ura
; PROGEDURES OMLETTELONA
SECTION."
IN NUCLEAR SCIENCE ABSTRACTS |
Submitted to the Journal of the American Ceramic Society for publication.
*Research sponsored by the U. S. Atomic Energy Commission under contract with the
Union Carbide Corporation.
LEGAL NOTICE
The report was propered um nome al Covenant sponsored work. Metther the wind
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A. Mahn voruty or punctatou, aprund or land, ma nepoct to the soci-
moy, completos.se, or watalon at the leformation contained to the report, or that the wo
meg tudor nation, rest, wethed, of pracow doomed to do soport may not to bring
potrily owned photos of
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not commodo, or Memployment with no contrastos.

-2
ABSTRACT
The behavior of sintered Beo exposed to fast-neutron doses up to 8 x 10%
neutrons am"? was investigated at 110, 650, and 1100°C with the objective of the
establishing its limits of stability and mechanisms of damage under conditions to
which it would be exposed if used as a moderator in nuclear power reactors. The
data are generally consistent with the hypothesis that grain boundary separation,
the primary mode of damage to Bed compacts at all three temperatures, is caused by
anisotropic crystal expansion, which results from the production of point defects
and the agglomeration of defects in the crystal lattice. At 1100°C, a temperature
at which in-pile annealing substantially reduces crystal expansion, the data indicate
that grain boundary separation is promoted by thermal cycling. To minimize damage
in nuclear reactor operation, Beo of small grain size and low density should be used,
the temperature should be as high as practicable, and thermal cycling should be
avoided.
I.
INTRODUCTION
Sintered or hot-pressed beryllium oxide has been considered for use as a
moderator or fuel matrix material in nuclear reactors designed for high-temperature
performance. The attractive nuclear and physical properties of Beo make it ideally".
suited for such applications, but its limits of stability toward fast neutrons
needed to be determined before it could be incorporated into practical reactor
designs. Consequently, there have been efforts by many investigators in the United
States, the United Kingdom, France, and Australia to establish these limits and to
evaluate the mechanisms of damage.
Much of the large amount of data accumulated on the radiation behavior of Beo
cannot be compared satisfactorily because of the diversity of types of BeO specimens
-3. .
studied and the differences in reactor operating parameters. For this reason, in a
continuation or the Beo irradiation program at the Oak Ridge National Laboratorycol,::
a series of experiments was designed to permit comparisons of damage to specimens
of different grain sizes and densities as a function of neutron flux, dose, and
temperature under controlled conditions. Another major objective was to determine
the mechanisms by which Beo is damaged when irradiated to the very high fast-neutron
. doses to which it would be exposed in nuclear power reactors. This paper presents
.
.
the results obtained from these experiments
II. EXPERIMENTAL DETAILS
(1) Characteristics of Specimens
The characteristics of the eight groups of cylindrical samples Irradiated in the
experimental assemblies are given in Table I. All the samples were prepared by the ***
Metals and Ceramics Division, Oak Ridge National Laboratory, from the same batch of
Brush Beryllium Company UoX Grade FeO powder by cold-pressing and sintering at 1750°c
in a hydrogen atmosphere. The material of small grain size, was sintered for one
hour, and the material of large grain size was sintered for 60 hours. The low-
density samples were made by including epoxy resin in the pressed material and
removing it by heating at 900°C in air before sintering.
(2)
Irradiation Assemblies
The specimens were enclosed in stainless steel capsules and irradiated in the
Idaho Engineering Test Reactor (ETR) at 110, 650, and 1100°C. Temperatures were
achieved by gamma heat generated within the capsules. The arrangement of the
capsules within the flux profile of the reactor position, the temperature of each
capsule, and the irradiation times are shown in Fig. 1. Each narrow bar represents
a capsule containing 30 1/4-1n. specimens; each wide bar represents a capsule
containing 15 1/2-in.. specimens. All four types of Beo were arranged in each capsule
... annem
4.
TYY
1
.
1
.
ti
.
wollen
in eccordance with the principles of statistical design.
(3) Determination of Neutron Dose
The values of the fast-neutron dose were calculated from measurements of the
Mnactivity in stainless steel discs located at the top and bottom of each
capsule. A cross section of 54 millibarns for the Fe54(n,p): 54 reaction and a :
half-life of 314 days were used in the calculations. A Watt is spectrum value of
0.692 was used for the integration of fission-neutron energy above 1 Mev.
III. IRRADIATION OF BERYLLIUM OXIDE AT 110°C
(1) Gross Damage (Fracturing and Powdering)
The gross damage to specimens irradiated at 110°C 18 summarized in Table II,
An exemination of the damage data revealed no significant differences between types
of Bed at this temperature. Although major fracturing of Type It began at a lower----
neutron dose than in other types, a larger number of specimens of Type II survived
intact up to a dose of 2 x 1021 neutrons cm2. Consequently, this difference 18 not
considered to be significant. Nearly all specimens disintegrated to powder at doses
above 2 x 1021 neutrons cm-2.
(2) Volume Expansion
Figure 2 shows the volume expansion of samples which survived the low temperature
irradiation without fracturing or powdering plotted against fast-neutron dose. It
is apparent that there are no significant differences in volume expansion among the 1
four types of BeO Irradiated in this experiment. Also shown in the plot is the
volume expansion calculated from density measurements of single crystals irradiated
in the same experimental assembly and the volume expansion calculated from the
lattice parameters from X-ray diffraction examinations of powdered Beo compacts. 10.
Self-constraint in the relatively very large single crystals may account for the
lower values found for their volume increases as calculated from density changes
-5.
compared with values calculated from lattice expansion of powdered specimens.
Obviously, grain boundary separation contributes importantly to the expansion of
compacte irradiated to doses above ~0.8 x 102neutrons cmma (> 1 Mev).
Micrographic Exami.nations
Photomicrographs of Beo irradisted at low temperatures reveal extensive grain
boundary separation, which is the primary manifestation of domage. Transgranular
fracture also occurs to some extent, particularly in large-grained samples, but
only rarely does it traverse more than one grain. The effeci of fast-neutron .
Irradiation on Bed at 110°c is 1llustrated by a comparison of unirradiated Beo, :
shown in the photomicrograph of Fig. 3, with irradiated Beo of the same type in
Fig. 4o
(4) X-Rey Diffraction Examinations
The changes in the lattice. parameters of specimens irradiated at 110°C are
given in Table III. These data were obtained from measurements of the 2?. •1 and 21.0
reflections using Ni Ka X-radiation, and represent the average and a parameters
including the agglomerations of defects between some of the planes. 20 Values of
lattice parameters reported for specimens of previous experiments were calculated
from reflections observed as diffuse maxima with copper Ko X-rays, whose Brage
spacings are not a simple function of the average interplaner distances in the
crystal. Crystal expansion, which is greater in the direction of the g axis than the
a axis, varies from 1.2 to 3.5% over the dose range 0.7 to 2.23 x 1021 neutrons cm - 2
(> 1 Mev). The anisotropic expansion ratio, (Ac/s)/(48/s.), averages about 20.
IV. IRRADIATION OF BERYLLIUM OXIDE AT 650 AND 1100°C
The four types of Beo were irradiated at both 650 and 1100°C in two experiments
which were similar except that the irradiation time of one was about twice that of
the other. The purpose of this procedure was to permit comparisons of the radiation
e monttinn
Lor
damage to specimens of the same types irradiated to the same fast-neutron doses for :
different fast-neutron flux values. In conjunction with the Irradiation experiments,
out-of-pile control tests were carried out to determine the effect of thermal
treatment alone on Beo specimens of these types.
(1) Out-of-P1le Control Tests
Tests weze conducted out-of-pile in which the four types of Beo were subjected
to the same thermal treatment that the specimens received during irradiation. This
.
irradiation experiments.
.'.
•
Examinations of the specimens after conclusion of the tests showed no gro88..
.
fracturing or significant dimensional changes as a result of the thermal treatment
at either. 650 or 1100°C. Photomicrographs of the samples in the as-polished
.condition at 100x magnification revealed no grain boundary separation or transgranular
fracture. The out-of-pile tests do not, of course, provide a temperature differential
necessary for determining the effect of thermal stress, which may be important in
irradiation studies.
(2) Gross Damage to Irradiated Specimens:
The experimental conditions and the gross damage data (fracturing and powering).
are summarized in the bar grapa of Fig. 5; each of the bars covers the range of
fast-neutron exposure of the specimens of the type represented. The boundaries of
the damage regions shown in the bar graph are approximate. Some samples survived
without visible grosu damage, although in a greatly weakened condition, even in
fast-neutron dose ranges where most samples of the same type were severely fractured
or powdered. Post-Irradiation removal of the thick steel cladding required to achieve
the necessary gamma heating of the capsules containing the quarter-inch samples proved
to be very difficult. The gross damage data for these samples are not presented . :
.
.
.
1
+
.
------
--------------...--.---------
--
-
-----------
mode my do ma
s omo
Several conclusions may be drawn from the data summarized in Fig. 5:
1. The gross dainage, which increases with increasing dose, is greater at
650 than at 1100°c for all four types of Beo.
2. Powdering of Beo compacts, which previously has been observed only in low
temperature irradiations, can occur at temperatures as high as 1100°c
after exposure to doses greater than 4 x 1021 neutrotis cm(> 1 Mev).
3. In general, Type I Beo (low density, small grain size) withstood irradiation
better than the other types in both experiments, while Type IV Beo (high
density, large grain size) was generally damaged to a greater extent than
the other types, particularly in Irradiations at 650°C.
4. Unexpectedly, there is no #adication that damage is greater to samples
irradiated in high fast-neutron fluxes than to samples irradiated in low
fluxes at equivalent fast-neutron doses.
There is less damage to samples irradiated at 650°C than to samples Irradiated
at 110°c (see Table II) for equivalent doses. This indicates that some in-pile
annealing occurs even at temperatures as low as 650°C. ·
The increase in volume of the hall-inch Beo compacts which survived irradiation
· without severe fracturing in the short-term experiment and the long-term experiment
18 plotted against fast-neutron dose in Figs. 6 and 7, respectively. The volume
expansion of the quarter-inch specimens is not included because the dimensional data
for these specimens were not consistently reliable.
As can be seen in Fig. 6, the specimens irradiated at 650°C, which expanded less
than specimens irradiated at 110°c, expanded considerably more than the samples.
irradiated at 1100°C. In Irradiations at 1100°C, it is clear that Type I Beo (low :
density, small grain size) expanded much less than Type IV (high density, large
grain size). Types II and III were intermediate in expansion.
:
-8.
:
There was no survival in irradiations at 650°C in the long term experiment.
The volume increases of the four types of samples irradiated at 1100°C in the long-
term experiment, shown in Fig. 7, are in the same order as in the short-term
experiment, with Type I expanding the least, Type IV expanding the most, and Types
II and III Intermediate. In botia experiments, the volume expansion increases with
increasing fast-neutron dose.
: If the volume expansions for irradiations at 1100°C in the two experiments are
compared at equivalent dose values (see Table IV), it is apparent that there is
greater expansion in the long term experiment than in the short-term experiment. This
unexpected finding of greater expansion in lower fluxes for equival.ent doses can
possibly be explained as an effect resulting from reactor operational variables
such as thermal cycling. For instance, the long-term experimental assembly
experienced three times the number of thermal cycles (132) during irradiation as
did the short-term assembly (45). Thermal cycling of anisotropically strained.
boundaries during each cycie. A greater number of thermal cycles during an
irradiation could result, consequently, in greater expansion caused by grain 'boundary
separation.
(4) Micrographic Examinations
Photomicrographs of Beo compacts Irradiated at 650 and 1100°C clearly show
extensive grain boundary separation as well as some transgranular fracture.•,7 In
samples of large grain size (~ 70 m) Irradiated to dosez exceeding 3 x 1022 .
neutrons cm2 (> 1 Mev), transgranular fracture accounts for an apparent reduction
in grain size of about 25%. Samples with smaller grains (~ 23 ) also show trans- :.
granular fracture but not enough to reduce the apparent grain size by a significant
amount. In both cases, however, the primary mode of damage is grain boundary
separation.
(5) X-Ray Diffraction Examinations
Results of X-ray diffraction examinations do of selected Beo samples Irradiated
at 650 and 1100°C are presented in Table V. The values for the g parameter were
calculated from measurements of the 21•1 and 21•0 reflections of Ni Ka X-radiation from
Beo compacts ground to a fine powder.
Almost all the volume expansion calculated from the lattice parameters results
from the increase in the c parameter; the a parameter Increase is negligible in
irradiations at 650 and 1100°C. The anisotropic volume Increase calculated from
the laºtice parameters of samples irradiated at 650°c (1.4 to 2.2%) 18 considerably
less than that of samples irradiated at 110°c (see Table III). The increased rate
of in-pile annealing at 1100°C substantially reduces the g parameter increases from
the values found for samples irradiated at 650°C.
Comparisons of different Beo types in Table V provide no indication, within the
precision of the data, that density and grain size have a bearing on lattice
parameter increase. No flux intensity effect at 650°C 18 apparent from comparisons
of data from the two experiments at comparable neutron doses. Because in-pile
annealing at 1100°C should be very rapid, a marked flux intensity effect would be
expected. The lattice parameter measurements on samples irradiated at 1100°C,
however, are not precise enough to demonstrate this effect conclusively.
.
.. . .
V. DISCUSSION AND SUMMARY
. The experimental results are generally consistent with the hypothesis that
point defects produced by fast neutrons cause misotropic expansion of the Beo
crystals, predominantly in the direction of the c axis, which, in turn, produces
grain boundary separation in randomly oriented compacts. Photomicrographs clearly
showed that grain boundary separation is the primary mode of damage at all temperatures
from 110 to 1100°C, although some transgranular fracture is evident, particularly in
specimens of large grain size. Most changes in the physical properties of Feo bodies
..
-10
irradiated to high doses can be accounted for by grain boundary separation
augmented by transgranular fracture. These changes include fracturing and powdering,
volume expansion, which has proved to be a reliable criterion of fast-neutron
damage, and large reductions in the crushing strength and thermal conductivity.
The anisotropic volume expansion of a Bco crystal may be considered to be the
sum of (1) the anisotropic volume expansion as calculated from the lattice parameters,
and (2) the volume expansion produced by agglomerations of defects between some of
the basal planes which are too large to be included in the g parameter increase.
Single crystals Irradiated at 650 and 1100°C, which are very large relative to
crystals in Beo compacts, show a dark banding parallel to the basal planes, which
probably consists of very large Beo defect agglomerations. The volume expansion of
these crystals 18 larger than that calculated solely on the basis of lattice parameter
increases.
The anisotropic crystal vo.Lume expansions at 110 and 650°C (w 1 to 3%) are
certainly large enough to produce grain boundary separation. The only case in which
taere 18 a question concerning whether anisotropic expansion is the doninant mechanism ..
arises in irradiations at high temperatures (1100°c). The lattice expansion at
1100°C is very small, and volume expansion calculated from density measurements of
single crystals was found to be no greater than 0.9% even for fast-neutron doses
exceeding 5 x 102 neutrons cms. Because crystal expansions of 0.9% or less
produce very little grain boundary .separation at 110°C, the possibility has been
considered that at high temperatures, grain boundary separation is produced by gas
pressure of helium, which diffuses to the grain boundaries after its production
within the grains by neutron reactions.
-11-
There is no indication of a flux intensity effect on gross damage, volume
expansion, or lattice parameter expansion in irradiations at 650°c. ' At 1100°c, a
temperature at which in-pile annealing should be very effective, there is also
apparently no flux intensity effect on gross damage. Surprisingly, however, volume
expansion is greater in low fluxes than in high fluxes for equivalent doses. A
proposed explanation is that thermal cycling can promote grain boundary separation in
compacts with anisotropically strained grain boundaries. Accordingly, there could
term, low-flux irradiations than in short-term, high-flux irradiations for equivalent
doses. This explanation could also account for the unexpectedly large amount of
grain boundary separation in samples irradiated at 1100°c relative to the small
amount of crystal expansion observed.
In order to minimize fast-neutron damage to a Beo ceramic body used as a
moderator in a nuclear reactor, the temperature should be maintained as high as
practicable, and the material should be of low density and small grain size. Because
of in-pile annealing at high temperatures, a low fast-neutron flux would probably
produce less damage than a high flux for equivalent neutron doses. A more important
factor in minimizing damage, however, may be the maintenance of the material at its
operating temperature during its entire period of use. The data at 1100°c indicate
that grain boundary separation in Beo bodies, with the consequent deterioration of
physical and mechanical properties, may be promoted by thermal cycling during
Irradiation.
: ; VI. ACKNOWLEDGEMENTS
The authors are grateful to G. M. Watson for his encouragement and helpful,
discussions covering all phases of this work. The authors gratefully acknowledge
the contributions of the following individuals at the Oak Ridge National Laboratory:
-12-
A. F." Zulliger and G. H. Hewellyn, engineering design of experimental assemblies;
1. L. Yakel, G. W. Clark, and R. M. Steele, X-ray diffraction examinations and
single crystal studies; E. Is. Long, Jr. and E. J. Manthos, micrographic examinations :
-
-
--
--
-
-
.
*.-.-K

.*,
LP
1
-13-
REFERENCES
1. Proceedings of International Conference on Beryllium Oxide, October 21-25,
1963, Sydney, Australia, J. Nuclear Materials (in press).
2. R. P. Shields, J. E. Lee, Jr., and W. E. Browning, Jr., "Effects of Fast
Neutron Irradiation and High Temperature on Beryllium Oxide", Oak Ridge
National laboratory Report ORNL-3164, March 16, 1962.
3. R. P. Shields, J. E. Lee, Jr., and W. E. Browning, Jr., "Irradiation Effects
on Beryllium Oxide", Trans. Am. Nucl. Soc. 4 (2) 338 (November 1961).
G. W. Kellholtz, J. E. Lee, Jr., R. P. Shields, and W. E. Browning, Jr.,
"Radiation Damage in Beo", Proc. Symp. Radiation Damage in Solids and Reactor
Materials, Venice, May 7-11, 1962, vol. II (Vienna, TAEA, 1962)..
5. G. W. Kellholtz, J. E. Lee, Jr., and R. E. Moore, "The Effect of Fast-Neutron
Irradiation on Beryllium Oxide Compacts at High Temperatures", Oak Ridge
National Laboratory Report ORNL-T-741, December 11, 1963.
G. W. Keilholtz, J. E. Lee, Jr., R. E. Moore, and R. L. Hamner, "Behavior of
Beo Under Neutron Irradiation", Oak Ridge National Laboratory Report ORNL-TM-
742, December 11, 1963.
G. W. Keilholtz, J. E. Lee, Jr., and R. E. Moore, 'The Effect of Fast-Neutron
Irradiation on Beryllium Oxide Compacts at High Temperatures", J. Nuclear
Materials 11 (3) 253-264 (1964).
8. R. L. Hamner, "Fabrication and Characterization of High-Purity Beryllium Oxide
. ..Specimens for Irradiation Testing", Oak Ridge National Laboratory Report
ORNL-TM-767, March 1964.
9. 1). A. Gardiner, "The Experimental Design for Beo Irradiation Experiments
ORNL 41-8 and ORNL 41-9", Oak Ridge National laboratory Report ORNI-3310,
July 2, 1962.
-14-
10. · H. L. Yakel and R. M. Steele, Metals and Ceramics Division, Oak Ridge
National Laboratory, personal communications.
....
-15-
Table I. Characteristics of Beryllium Oxide Specimens la)
Beo Type
Batch
Number
Specimen Size
Average Grain
(in.)
sverage Bulk
Density.
(8 cm-3)
2.7
All
0.25
0.5
A28
2.7
IT..
A13
0.25
0.5
A19
I. (Low density,
small grain size)
(Low density,
large grain size)
III. (High density,
small grain size)
IV. (High density,
large grain size)
AIO
0.25
0.5
8m no se
A16
2.9
A15
A17
2.9
2.95
0.5
(a) Right circular cylinders with the diameters equal to the heights.
-16.
Table II. Gross Damage to Hall-Inch Beo Specimens Irradiated at 110°C
.
* 2021
* 2022
Beo Type
Fast-Neutron Fast-Neutron Fast-Neutron
Dose Range Dose for Minor Dose for · Major Dose for Major
Fracturing Fracturing Fracturing wit
Powdering 2,
(neutrons am-2) (neutrons cm-2)(neutrons cm-(neutrons am 3)
x 1021 x 1021
I. (Low density, 0.61-2.23 1.1
1..6
small grain size)
II. (Low density, 0.56-2.23
large grain size)
III. (High density, 0.67-2.2
small grain size)
IV. - (of gh densitas ar
(High density, 0.5-2.22
large grain
2.1
-17-
Table III.
Results of X-Ray Diffraction Examination of BeO Irradiated at :
at 120°c (a):
Beo Type
sala
A/
AV/v. D)
Fast-Neutron Dose
(> 1 Mev)...
(neutrons cm )
Fast-Neutron Flux
(> 1 Mev).
(neutrons cm-sec
)
x 2022
THE H
* 2014
1.8
0.7
0.0120
1.67
4.3
0.0280
0.0010
0.0012
0.0013
0.0013
0.0100
0.0256
0.0298
0.0326
2.22
5.7
0.0324
0.0352
2.23
5.7
(a) Lattice parameters were calculated from measurements of the 21•1 and 21•0
reflections from Ni radiation from Beo compacts which were ground to a fine
powder.
(b) The fractional volume increase, AV/V., was calculated from the equation
AV/v. = 2(19/2) + (As/s.). .
-
-
...m
ore
.:
-28-
Table IV. Volume Expansion of Half-Inch Be0 Specimens Irradiated at 11
.
Irradiation Time
de
(sec)
Percent Volume. Increase at Fast-Neutron Dose
2.0 x 102 : 4.0 x 1024 . 7.2 x 102
neutrons comme neutrons com neutrons om
x 107
1.4
H.
2.2
..
2.4
..
H
0.733
1.4
III
1.4
3.1
III
IV
0.733
1.4
0.733
4.3
IV
.....
.
.
.
.
(a) The values of volume increase at the three neutron doses were interpolated
from linear data plots. Type II was omitted because there were too little
data' available, but the expansion appears to lie between Types I and IV.
. .
.
.
L
Table 1. Results of X-Ray Diffraction Examination of Beo Irradiated at 650 and 1100°c le.
Experiment (5) Beo Type Fast- Neutron Fast-Neutron Temp. sale. Acls..
Dose (> 1 Mev) Flux (> 1 Mev):.
.. (neutrons cm-2) (neutrons cm-2 sec-1) (°c)
AV/v. (c)
:
noticias de los downloader
x 2021
x 1024
41-9
.
.
1.4
1.9
2.25
0001
5.0
5.1
650
650
OOOOOO
IV
1.6
650
0.0001
41-9
41-9
41-9
41-8
41-8
41-8
41-8
41-8
41-8
41-8
41-8
II
II
2.05
2.2
0.0150
0.0158
0.0140
0.0226
0.0152
0.0114
0.0205
0.0191
0.0194
0.0212
0.0209
0.0204
0.0150
0.0158
0.0142
0.0226
0.0154
0.0114
0.0205
0.0191
0.0194
0.0212
0.0217
0.0214
2.35
650
II
650
5.1
7.95
650
650
650
0.0004
0.0005
-19
do 65
2.25
1.8
4.0
41-9
41-9
41-9
41-9
41-8
41-8
41-8
41-8
4.0
II
0.0019
0.0034
0.0016
1.65
3.2
um ama
1100
1100
1100
1100
1100
1100
1100
1100
IV
0001
.0001
0.0019
0.0034
0.0018
0.0002
0.0028
0.0002
IV
5.5
0.0028
5.9
0.0001
**
(a) Lattice parameters were calculated from measurements of the 21•1 and Ź10 reflections of Ni Ka X-radiation from
Beo compacts irradiated in Experiments 41-8 and 41-9 which were ground to a fine powder.
(b) Irradiation times of Experiments 41-8 and 41-9 were 1:4 x 10' and 7.33 x 10° sec, respectively. .
The fractional volume increase,
is calculated from the equation
.
.
.
.
.
.
.
.
PV
M
.
-20-
FIGURE CAPTIONS
1.
2.
3.
4.
Arrangement of capsules within the neutron flux profile of the Engineering
Test Reactor, in which sintered BeO specimens were irradiated at 110, 650, and
1100°C, ORNL-DWG-64-11199.
Volume Increase of 1/2-1n. Beo compacts and single crystals Irradiated at
110°C vs fast-neutron dose, ORNL-DWG-64-8398R.
Unirradiated Beo of high density (~ 2.9 g/cm) and small grain size (~ 25 m),
as-polished at 100x magnification, 'Y-45357.
High density Beo (~ 2.9 g/cm") of small grain size (~ 25 M) Irradiated to a
fast-neutron dose of 0.78 x 1022 ueutrons cm2 (> 1 Mev) at 110°C (as polished,
100x magnification), R-22003.
Gross damage to Beo specimens irradiated at 650 and 1100°c for two periods of _--
time as a function of the fast-neutron dose, ORNL-DWG-64-1886.
Volume increase of 1/2-in. BeO specimens irradiated at 650 and 1100°C in
short-term experiment 41-9 (7.33 x 200 sec) vs fast-neutron dose, ORNL-DWG .
63-1936R.
Volume increase of 1/2-in. BeO specimens irradiated at 1.100°c in long-term
Experiment 41-8 (1.4 x 107 sec) vs fast-neutron dose, ORNL-DWG-64-4404R.
5.
6.
.-
-
-...-...
7.
.
-
arm.
..
.
..
..
i
Z
... UNCLASSIFIED
ORNL-DWG 64-1199
EXPERIMENT NUMBER
141-8
41-9
.
41-10

0000
WERSA8888
1400
2
니니니니니
​.
1100
ONLOAD CRIP.
REACTOR
|
.
.
000 12
.
0
Oo
3을
​CELL
14
so
sol ssal Mol
1 110
1
1.4 x 40
7.33x406
|
3.9 x 106
6
|
0
.
2 4 6
px 404 > Mev)
.
IRRADIATION TIME (sec) |

CAPSULE NUMBER
TEMPERATURE (°C) --
Fig. 1 1
11
UNCLASSIFIED
ORNL-DWG 64-8398R
SOLID SYMBOLS - VOLUME INCREASE FROM
DIMENSIONAL MEASUREMENTS
OPEN SYMBOLS - VOLUME INCREASE CALCULATED
FROM LATTICE PARAMETERS
• 1
LOW DENSITY (~2.7 g/cm3)
SMALL GRAIN-SIZE (174)
III
LOW DENSITY (~2.7 g/cm3) ·
LARGE GRAIN-SIZE (~ 34u)
HIGH DENSITY (~2.9 g/cm3,
SMALL GRAIN-SIZE (~ 25 p)
HIGH DENSITY (~2.9 g/cm3)
IV
LARGE GRAIN-SIZE (~ 74 u/
SINGLE CRYSTALS
. A III

T À 110 °C
6
FROM DIMENSIONAL
MEASUREMENTS OF
BEO COMPACTS –
CALCULATED FROM AVERAGE LATTICE
PARAMETER EXPANSIONS IN POWDERED
REFLECTIONS, Cu-RADIATION)
VOLUME INCREASE (%)
CALCULATED FROM DENSITY
MEASUREMENTS OF SINGLE CRYSTALS
0.4
0.6
0.8
2.2 (x1021)
.
1.0 1.2 1.4 1.6 1.8 2.0
FAST-NEUTRON DOSE (neutrons / cm2 , > I Mev)
1.
Fig. 2
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INCHES
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:. .
:
ب
ه
.:
: ۰۹ : ۲
. .,
.
.
.
.
.
.
T
.:
.
و... م .. .. .......
و
..
و
و
-
مه مه.......
F1s. 3
|
ا
.
و
(
::.
مه ل مننهنان مسنان
دد
.
.
.. ..
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ہ... همه
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.. ها . . . . سمند ، شیر
منفعه
.
.
. .
.

Fig. 4

1
.
A
.-
mi
-
.
:
10.01
•. .
A
10.00
.
-
--
-.-.-.-.-.----...
'
* ...-......
.
TV
Time
UNCLASSIFIED
ORNL-DWG 64-1886
BeO TYPE
LOW DENSITY (~2.7g/cm3) HIGH DENSITY (~2.9 g/cm3)
SMALL GRAIN-SIZE (17)
SMALL GRAIN-SIZE (~254)
LOW DENSITY (~2.7 g/cm3) NY HIGH DENSITY (~2.9g/cm3)
“LARGE GRAIN-SIZE (~34u) LARGE GRAIN-SIZE (~744)
NO OBSERVABLE DAMAGE
MAJOR FRACTURING
2 MINOR FRACTURES
MAJOR FRACTURING
WITH POWDERING
ños 60
FAST-NEUTRON DOSE (neutrons/cm, >1 Mevl že

m
n
Y
...
o
.
I II III IV I II III IV
I II III IV I II III IV
41-9-TIME, 41-8-TIME,
41-9-TIME, 41-8-TIME
7.33x 10 sec 1.4 x 107 sec . 7.33x 10 sec 1.4x107 sec
1100°C
650°C....
BeO TYPE AND TEMPERATURE
Fig. 5
OH
-
.
-
-
-
---
ORNL-DWG 63-1936R
• 1100 °C, LOW DENSITY (~2.7 g/cm3)
o 650 °C . SMALL GRAIN-SIZE (17)
u 1100 °C .. LOW DENSITY (~2.7 g/cm3)
650 °C -- LARGE GRAIN-SIZE (~34 )
A 1100 °C ... HIGH DENSITY (~2.9 g/cm3)
a 650 °C - SMALL GRAIN-SIZE (~254)
1900 °C
650 °C "V
LARGE GRAIN-SIZE (~74 H)
HIGH DENSIT

I, II AND III-650 °C
VOLUME INCREASE (7)
IV-1100 °C
III-1100 °C
11--1100 °C
-
FAST-NEUTRON DOSE (neutrons/cm2 > 4 Mev) .
.
Fig. 6
UNCLASSIFIED
ORNL-DWG 64-4404R
LOW DENSITY (~ 2.7 g/cmos
SMALL GRAIN-SIZE (~174)
, LOW DENSITY (~ 2.7 g/cm3)
LARGE GRAIN-SIZE (~ 34u)
HIGH DENSITY (~2.9 g/cm3)
SMALL GRAIN-SIZE (~254)
, HIGH DENSITY (~ 2,9 g/cm3)
LARGE GRAIN-SIZE (~744)

T~ 1100°C
Ill
VOLUME INCREASE (%)
72 (x102)
1.6. 2.4 3.2 4.0 4.8 5.6 6.4
FAST-NEUTRON DOSE (neutrons/cm², >1 Mev)
Fig. 7
END



DATE FILMED
5 / 27 / 66








YL
.
.
.
.
..
pi, ....
R
.
--
.