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UNCLASSIFIED
ORNL
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630
ORNLP-631
CONF-792-1
NOV 1 3 1984
MASTER
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honammo, o pork b. , My worsellon puimui
b o nounler' contract
Whe Coun... or da empleyi .10 . cogirarlor.
Properties of Bell Compacts Irradiated at Fast-Neutron Doses Greater than
2021 Neutrons/cm2 *
G. W. Keilholtz
J. E. Lee, Jr.
R. E. Moore
Reactor Chemistry Division, Oak Ridge llational Laboratory, Oak Ridge, Tennessee
*Research sponsored by the U. S. Atomic Energy Commission under contract with tz
Union Carbide Corporation.
Paper to be presented at the American Ceramic Society Meeting, San Francisco,
October 28-30, 1964.
Table of Contents
Introduction
Experimental Design
Low Temperature Irradiations (~ 120°c)
High Temperature Irradiations (650 and 1100°c)
Gross Damage Effects
Volume Expansion
Micrographic Examinations
X-ray Diffraction Examinations
Single Crystal Studies
Discussion and Summary
9
.
.
.
.
Introduction
The BeO-irradiation program at ORNL, now of several years duration, has been
directed primarily toward the determination of the effects of high fast-neutron
doses (> 1021 neutrons/cm2) at elevated temperatures (up to 1100°c) on pure Beo
compacts without additives. One of the major objectives has been to evaluate the
mechanisms of fast-neutron damage under conditions to which Beo moderator bodies
may be subjected in nuclear power reactors.
Much of the large amount of data on the neutron irradiation of beryllium
oxide, accumulated by many different investigators, cannot be compared satisfactorily
because the data were obtained from Beo compacts made from different starting
materials and fabricated by different methods. Also important, there may be sizable
discrepancies in the flux, dose and temperature values in different axperimental
assemblies and reactor systems. For these reasons, a series of experiments was
designed to permit comparisons of radiation damage to Beo compacts of different
grain-sizes and densities as a function of the flux, dose and temperature under
controlled conditions.
This paper presents the results of these experiments.
Experimental Design
The irradiation experiments (41-8, 41-9, and 41-10) were designed to determine
the effect of fast-neutron irradiation on sintered Beo compacts of different
densities, grain-sizes and specimen sizes as a function of the fast-neutron dose,
fast-neutron flux and the temperature. There were two sizes of sintered cylindrical
specimens (1/2 in. length x 1/2-in. dia. and 1/4-in. length x 1/4 in. dia.) for each
of four types of sintered Beo (two densities and two grain sizes). The characteristics
of the eight groups of samples irradiated in the experimental assemblies are given
in Table 1. All the samples were prepared from tiie same batch of Brush Beryllium
Company VOX Grade BeO powder by cold-pressing and sintering at 1750°C in a hydrogen
atmosphere. The material of fine grain-size was sintered for one hour, and the
ole
material of large grain-size was sintered for 60 hours. The low-density Beo
samples were made by including epoxy resin in the pressed material and removing
1t by heating at 900°C in air before sintering.
The specimens were encapsulated in stainless steel and irradiated in the Idaho
Engineering Test Roactor at 110, 650 and 1100°c. Temperatures were achieved in
each case by gamma heat generated within the capsules (1, 2).
The arrangement of the capsules in the experiments is shown in Fig. 1. Each
narrow bar represents a capsule containing so 1/4-in. specimens; each wide bar
represents a capsule containing 15 1/2-in. specimens. All four types of Beo
samples were included in each of the capsules. Each of the eight capsules of
Experiment 41-10 was maintained during irradiation at approximately 110°C. In
both Experiments 41-8 and 41-9 which were irradiated for different periods of time
in order to achieve a separation of the flux and dose parameters, four capsules
were maintained at 650°C and four were maintained at 1100°c.
Low Temperature Irradiations_(~ 110°c)
The four types of Beo compacts were irradiated at approximately 110°C over
the fast-neutron dose range 0.5 to 2.23 x 1024 neutrons/cm² (> 1 Mev). The fast-
flux ranged from 1.3 to 5.7 x 1074 neutrons/cm² sec (> 1 Mev). The gross damage
to specimens irradiated in this experiment is summarized in Table 2. An examination
of the damage data revealed no significant differences between types of Beo.
Although major fracturing of Type II began at a lower neutron dose than other
types, a larger number of specimens of Type II survived intact up to a dose of
2 x 1022 neutrons/cm². Consequently, this difference is not considered to be
significant. Nearly all specimens disintegrated to powder at doses above 2 x 1024
neutrons/cm2.
.
..
Volume expansion calculated from dimensional increason of the irradiated
samples was found to increase nearly linearly from about 1.25% at a fast-neutron
dose of 0.5 x 1021 neutrons/cm2 to ubout 5.5% at 1.4 x 1021 neutrons/cm2. There
WAB a levelling off at higher doses, reaching about 6% at 2 x 102 neutrons/cma.
Figure 2 shows the volume expansion of samples which survived without fracturing
or powdering plotted against fast-neutron dose.
It is apparent that there are no
significant differences in volume expansion among the four types of Beo irradiated
in this experiment. Aloo 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. 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 compared with values calculated from
lattice expansion of powdered specimens. Obviously, grain boundary separation
contributes most of the expansion of compacts irradlated to doses above ~0.8 x 1021
neutrons/cm? (> 1 Mev).
Two mechanisms have been proposed to explain grain-boundary separation in BeO
compacts exposed to fast-neutron irradiation: (1) anisotropic expansion of randomly
oriented crystals, resulting in stresses at the grain boundaries which ultimately
overcome the intergranular bonding forces and (2) breaking apart of grain boundaries
by gas pressure of hellum, which diffuses to the grain boundaries after its
production by neutron reactions within the grains. In low temperature irradiations
(less than 250°C, for example) the evidence indicates that the hellum mechanism
cannot be significant. First, diffusion of helium to the grain boundaries should
be very slow at low temperatures. Second, grain boundary separation has been
observed in photonicrographs of Beo irradiated at very low fast-neutron doses where
very little helium has been produced (3, 4). On the other hand, X-ray diffraction
patterns of powdered BeO specimens irradiated at 110°C in Experiment 41-10 show
lattice parameter increases large enough to produce grain boundary separation; the
anisotropic expansion ratio (ac/s)/169/a) averages about 20 in these patterns.
The lattice parameters of specimens irradiated at 110°C are given in Table 3.
These data were obtained from measurements of the 21•1 and 21•0 reflections using
Ni-radiation, and represent the average c and a parameters including the
agglomerations of defects between some of the planes (5). Values of lattice
parameters reported for specimens i previous experiments (1) were calculated from
reflections observed as diffuse nii imt, but which represent spacings between those
planes which do not include defec: Selomerates.
High-Temperature Irradiations (650 ':nd 1100°C)
In each of the high temperatur". cxperiments (41-8 and 41-9), the four types of
Beo were irradiated at both 650 anri 1100°c. The two experiments were similar
was
except that the irradiation time of Experiment 41-8 was about twice that of
Experiment 41-9. The purpose of this procedure was to permit comparisons of the
radiation damage to specimens of the same types irradiated to the same fast-neutron
doses for different fast-neutron flux values.
Gross Damage Effects
The experimental conditions and the gross damage data (fracturing and powdering)
for the four types of half-inch BeO specimens irradiated in Experiments 41-8 and
41-9 are sunmarized in the bar graph of Fig. 3. Each of the bars covers the range
menito
of fast-neutron exposure of the specimens of the type represented. The boundaries
A
of the dange regions shown in the bar graph are approximate. Some samples survived
without visible gross damage, although in a greatly weakened condition, even in
fast-neutron dose ranges where most samples of the same type were severely fractured
e
S
or powdered.
.
CA
Several conclusions may be drawn from the data summarized in Fig. 3:
1. The gross damage, 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 neutrons/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 indication that damage is greater to samples
was
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 in Experiment 41-9 than
to samples irradiated at 110°C in Experiment 41-10 (See Table 2). This indicates
that in-pile annealing occurs even at temperatures as low as 650°C. Therefore,
the absence of a flux intensity effect on gross damage must be related to reactor
operational variables such as thermal cycling or thermal stress.
Volume Expansion
The increase in volume of the half-inch Beo compacts which survived
Irradiation without severe fracturing in Experiments 41-8 and 41-9 are plotted
against fast-neutron dose in Figs. 4 and 5, 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. 4, the specimens irradiated at 650°C in the short term
experiment (41-9) expanded less than specimens irradiated at 110°c in Experiment
41-10, but considerably more than the samples irradiated at 1100°C. No definite
differences in volume expansion among the four types of Beo irradiated at 650°C are
Y
5
evident, but in irradiations at 1100°c ít 18 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.
There was no survival. in irradiatione at 650°C in the long term experiment
(41-8). The volume expansion of the four types of samples irradiated at 1100°C,
shown in Fig. 5, are in the same order as in Experiment 41-9, with Type I expanding
the least, Type IV expanding the most, and Types II and III Intermediate. As in
the case for Experiment 41-9, 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 4), 1t 18 apparent that there 16
greater expansion in Experiment 41-8 than in Experiment 41-9. Thle unexpected
finding of greater expansion in lower fluxes for equivalent doses can possibly be
explained as an effect resulting from reactor operational variables such as thermal
· cycling. For instance, the long term experimental assembly (41-8) experienced
three times the number of thermal cycles during irradiation as did the short term
assembly (41-9). Thermal cycling of anisotropically strained grain boundaries in
a Beo compact may result, therefore, in fracturing of some of the boundaries with
each cycle. A greater number of thermal cycles during an irradiation could result,
consequently, in greater expansion caused by grain boundary separation.
Out-of-pile control tests were conducted in which specimens of all four types
of beryllium oxide were subjected to the same thermal treatment that the same four
types received during irradiation of Experiment 41-9 at 650 and 1100°c. During
the irradiation of Experiment 41-9 there were 45 thermal cycles of the reactor.
Dimensional measurements of the diameter and length of these specimens after the
conclusion of the tests showed that there were no significant changes. Photomicro-
RY
-9-
graphs of the samples in the as-polished condition at 100x revealed no grain-
boundary separation or transgranular fracture. Thermal cycling of unirradiated
beryllium oxide compacts, therefore, does not cause grain-boundary separation.
The results may mean that thermal cycling can cause grain boundary separation in
samples irradiated at 'high temperatures only if there is some radiation-induced
anisotropic strain on the boundaries.
Micrographic Examinations
Photomicrographs of as-polished specimens clearly demonstrate that grain-
boundary separation 18 the primary mode of fast-neutron damage in Beo compacts
irradiated at low temperatures or to high doses at high temperatures. Transgranular
fracture also occurs to some extent, especially in specimens of large grain size
(~ 70 u). Grain boundary separation in irradiated specimens is illustrated in Figs.
6 and 7. Figure 6 shows photomicrographs comparing unirradiated Beo of high density
- 10-
(2.9 g/cm”) and small grain-size (23 u) with Beo of the same type which was
irradiated at 1100°c to a fast-neutron dose of 3.92 x 1024 neutrons/cm2. Extensive
grain boundary separation can be seen. There is no significant reduction in
apparent grain size from that of the unirradiated Beo, indicating that transgranular
fracture is not severe. Figure 7 shows high density Bell of large grain size (70 m)
Irradiated to a dose of 3.4 x 1021 neutrons/cm? (> 1 Mev) at 1100°c. Separation
between grains appears to be wider than in the small-grained Beo, and there 18
evidence of a considerable amount of transgranular fracture. There 16 an apparent
grain-size reduction of about 25% as a result of the transgranular fracture.
X-Ray Diffraction Examinations
Results of X-ray diffraction examinations (5) of selected BeO samples irradiated
at, 650 and 1100°C in Experiments 41-8 and 41-9 are presented in Table 5. The
-
-
vaiues for the c parameter were calculated from measurements of the 21•1 and 21.0
-
-
-
-
reflections from Ni-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 lattice parameters of samples irradiated at 650°C 1s considerably less than
that of samples irradiated at 110°C (See Table 3), but it 18 large enough (1.4 to
2.2%) to cause grain boundary 'separation observed in photomicrographs of these
samples. 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.
There 18 a question whether the small anisotropic volume expansion (0.02-0.34%)
calculated from lattice parameters of samples irradiated at 1100°C can cause the
grain boundary separation observed in photomicrographs.
Most samples 11sted in Table 5 are of diametrically opposite type (Type I,
low density-small grain size and Type IV, high density-large grain size) to provide
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ܠܐܐܫ
a test of whether density or grain size affects lattice parameter expansion. The
data are scattered somewhat, but there is no indication, within the limits of.
precision of the data, that density and grain-size have a bearing on lattice
parameter increase.
A comparison of lattice parameter changes of samples irradiated in the short
term experiment (41-9) with those of the long term experiment (41-8) at comparable
fast neutron doses provides a suggestion of a flux intensity effect on crystal
damage. That is, the lattice parameter expansion tends to be greater for samples
irradiated in high fluxes than in low fluxes when samples irradiated to equivalent
doses are compared.
Single Crystal Studies (5)
Single crystals of beryllium oxide were irradiated in Experiments 41-8, 41-9
und 41-10 together with Beo compacts. The single crystals irraidated at 650°C in
Experiment 41-9 exhibited a dark banding parallel to the basal-planes which was not
seen in crystals irradiated at 110°C in Experiment 41-10. The crystals irradiated
Seo
at 650°C were found to be quite fragile, fracturing easily along the basal planes.
Optical and X-ray diffraction data showed that the material in the dark banding is
isotropic and amorphous, which strongly suggests that it consists of very large
regions of Beo defect agglomerates. These regions are so large that they would not
contribute to the values obtained for the c parameter through X-ray diffraction
examinations. Single crystals irradiated at 1100°C show some striations, but very
little as compared with crystals irradiated at 650°c. Apparently, at 1100°C in-pile
annealing of point defects is so rapid that very little long-range agglomeration
can occur.
12.
12.
1
In Figure 8 No. 2 shows the dark banding in a crystal Irradiated at 650°C
to a fast-neutron dose of 1.1 x 1022 neutrons/cm?, No. 4 18 a crystal irradiated
at 650°c to a dose of 4.1 x 1022 neutrons/cm2 in which the dark banding appears
to fill the crystal almost completely; No. 3 18 a crystal irradiated at 54°c to
3.6 x 1021 neutrons/cm?; and No. 1 18 an unirradlated crystal.
Discussion and Summary
Irradiation of sintered beryllium oxide compacts in high fast-neutron fluxes
produces crystal damage through production of point defects, as indicated by lattice
parameter expansion, and leads ultimately to grain boundary separation and
fracturing and powdering of the material. In Irradiations at ~ 100°c, a temperature
at which in-pile annealing of point defects is insignificant, the anisotropic
crystal volume expansion increases from about 1.25% to about 3.6% over the fast-
neutron dose range 0.7 to 2.2 x 1024 neutrons/cm2, which produces grain boundary
separation in the compacts. The grain-boundary separation produces an additional
volume expansion of irradiated compacts. The total volume expansion of compacts
Irradiated over this dose range increases from 2.5 to 6%. Many specimens irradiated
to doses greater than 104 neutrons/cm² fractured, and most samples disintegrated
to powder above 2 x 1021 neutrons/cm.
In-pile annealing of point defects occurs to some extent in Irradiations at
650°C, as evidenced by a reduction in the lattice parameter expansion compared with
Irradiations at 110°c. Microscopic examinations of relatively very large single
crystals irradiated at 650°C showed striations parallel to the basal planes which
consist of defect agglomerates much too large in size to be included in the
parameter expansion obtained from X-ray diffraction examinations. These defect
agglomerates produce an anisotropic crystal expansion in addition to that calculated
from lattice parameters. There 18 less total volume increase and gross damage at
.
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15
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*
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Stiri
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650°c than at 110°c. Although gross damage data for irradiations at 110°C showed no
significant differences among the four grain size-density combinations, in
Irradiations at 650°C, Beo compacts of low density and small grain-size withstood
irradiation better than other types, and Beo of high density and large grain-size
was damaged to a greater extent than the other type 3. No indications of a flux
intensity effect on gross damage can be found in comparisons of results of the long
term experiment with those of the short-term experiment.
Very small crystal volume increases were found in samples irradiated at 1100°C
where in-pile annealing must be quite effective. The anisotropic volume expansion
at 1100°c calculated from lattice parameter ranges from 0.02 to 0.34%. Density
measurements of single crystals irradiated at 1100°C, however, give values for
volume expansion as high as 0.9%. The additional expansion is probably a result
of defect agglomeration. There is a question as to whether crystal volume expansion
even as great as 0.9% can produce the amount of grain boundary separation and
i volume increase observed in the compacts irradiated at 1100°C. For example,
crystal volume expansion greater than 1% must occur before grain boundary
separation begins in irradiations at ~ 100°c. .
The gross damage and total volume expansion of Beo compacts irradiated at
1100°C 16 less than that at 650°C. The beryllium oxide compacts of low density
and fine grain-size are damaged less and expand less than the other types, and the
compacts of high density and large grain-size are damaged to the greatest extent
and expand the most.
If the gross damage to samples irradiated at 1100°C in the long-term
experiment and the short-term experiment are compared at equivalent fast-neutron
dose values, no indication of a flux intensity effect can be seen. If anything,
.
there is greater damage in low fluxes than in high fluxes. The data for volume
expansion clearly show, however, that there 18 greater expansion in low fluxes.
PS4
.14.
This unexpected result is difficult to explain as a radiation effect, particularly
in view of the fact that the lattice parameter data suggests that there is a flux
intensity effect on crystal damage. The explanation may be that reactor operational
variables such as thermal cycling cause grain-boundary separation in samples
Irradiated at high temperatures. There may be more grain-boundary separation in
long-term experiments with a greater number of reactor thermal cycles than in
short-term experiments. 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. High-temperature thermal
cycling may produce grain boundary fracture under conditions of slight anisotropic
strain.
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N
sų r.
WH
References
1.
G. W. Kellholtz, 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 (13) 253-64 (1964).
Q. W. Kellholtz, J. E. Lee, Jr., R. E. Moore, and R. L. Hamner, 'Bebavior of
Beo Under Neutron Irradiation", Oak Ridge National Laboratory Report
ORNL-TM-742 (December 11, 1963).
J. Elston, "Radiation Damage in Solids", Proc. Symp. Radiation Damage in
Solids and Reactor Materials, Venice, May 7-11, 1962, Vol. II (Vienna,
TAEA, 1962).
High Temperature Material: Program Progress Report, No. 12, Part A, Nuclear
Materials and Propulsion Operation, Flight Propulsion Laboratory Department,
General Electric, Cincinnati (USA) Report GEMP-21A (June 15, 1962).
L. Yakel, Metals and Ceramics Division, Oak Ridge National laboratory,
personal communication.
4.
5.
14.
Table 1. Characteristics of Beryllium Oxide Specimens Irradiated in Experiments
41-8, 41-9, and 41-10
Beo Type
Batch
Mumber
Specimen Size
(in.)
Average Bulk
Density
Average Grain
Size
I.
(Low density, small and
All
(Low density, small
grain-size)
0.25
0.5
.25
2.7
2.7
2.7
A18
II.
(Low density, large
grain-size)
Al3
Alg
0.25
0.5
2.7
2.7
Sin
(High density, small
grain-size)
0.25
0.5
2.9
2.9
ANO
IV.
IV. (enten en eety, large
(High density, large
grain-size)
and
n
2.9
o tes
0.25
de
A17
0.5
Table 2. Gross Damage to Half-Inch BeO Specimens Irradiated in Experiment 41-10
(~ 11000)
Beo Type
Fast-Neutron Fast-Neutron Fast-Neutron Fast-Neutron
Dose Range for Minor Dose for Major Dose for Major
(neutrons/cm2) Fracturing . Fracturing Fracturing with
(neutrons/cm) (neutrons/cm2) Powdering
(neutrons/cm2)
x 2021
* 1021
* 2022
x 1021
I.
0.61-2.23
1.1
1.6
2.0
(Low density,
small grain
size)
II.
0.56.2.23
(Low density,
large grain-
size)
le remotys
-
0.56
0.56
2.0
III.
0.67-2.2
1.3
2.0
(High density,
small grain-
Bize)
IV.
0.5-2.22
1.5
2.1
(High density,
large grain-
size)
-15-
Table 3. Kesults of X-Ray Diffraction Examination of Beo Irradiated at 110°C in
Experiment 41-10*
Beo Type Fast-Neutron Dose
Fast- Neutron Flux
Fast-Neutron Flux 13/. Ac/S AV/v.**
(> 1 Mev)
(> 1 Mev)
(neutrons/cm2)
(neutrons coma sec)
x 2021
* 2014
1.8
4.3
0.7
1.67
2.22
2.23
0.0010 0.0100
0.0012 0.0256
0.0013 0.0298
0.0013 0.0326
0.0120
0.0280
0.0324
0.0352
5.7
5.7
*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.
** The fractional volume increase, AV/V., was calculated from the equation
AV/v. = 2(/,) + (Ac/s).
16.
Table 4. Volume Expansiou of Half-Inch Beo Specimens Irradiated in Experiments
41-8 and 41-9 at 1100°c*
Beo Type
Experiment
Percent Volume Increase at Fast-Neutron Dobe
2.0 x 1021 4.0 x 1021 7.2 x 1022
neutrons/cm neutrons/cm2 neutrons/cm
2.0
2.2
41-8
· 41-9
0.7
1.4
III
41-8
2.8
3.1
III
41-9
1.3
2.6
IV
41-8
4.0
4.3
41-9
2.6
* 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.
0
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JULI
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Table 5
Results of X-Ray Diffraction Examination of Beo Irradiated at 650 and 1100°C*
Temp.
a/a.
Ac/c.
AV/Vo**
Experiment Bell Type Fast-Neutron Fast-Neutron
Dose (>1 Mev) Flux (>1 Mev)
neutrons/cm2 neutrons/cm2
* 2022
x 2014
41-9
IV
1.'
1.65
1.9
650
3.6
650
요요요요요
​0 0.0150
0.0158
0.0001 0.0140
0.0226
0.0212
0.0004 0.0209
2.25
5.0
5.1
3.65
5.7
0.0150
0.0158
0.0142.
0.0226
0.0212
0.0217
3.7
5.1
7.95
65
650
650
1.8
4.0
IV
41-9
41-9
41-9
.41-9
41-8
41-8
4.0
2.25
2.45
5.5
5.5
1.2
2.3
II
·
1100 0
1100
1100
0.0019
1100
0.0034
1100 0.0001 0.0016
1100 0.0001 0
1100
0.0028
1100 0.00010
0.0019
0.0034
0.0018
0.0002
0.0028
0.0002
IV
142-8
3.9
41-8
4.2
Lattice parameters were calculated from measurements of the 21.1 and 21.0
reflections from Ni-ravitation from Beo compacts irradiated in Experiments
41-8 and 41-9 which were ground to a fine powder.
**
The fractional volume increase, AV/vo, was calculated from the equation
* = 24 + 4
.
-18-
Figure Captions
1. ORNL-41 Beo Irradiations, ORNL- LR-DWG-71668R.
2. Volume Increase of 1/2-in. Beo Compacts and Single Crystals vs Fast-Neutron
Dose in Experiment 41-10, ORNL-DWG-64-8398.
3. 'Gross Damage to Beo Specimens in Experiments 41-8 and 41-9 as a function of
the Fast-Neutron Dose and Temperature, ORNL-DWG-64-1886.
4. Volume Increase of 1/2-in. Beo Specimens vs Integrated Fast-Neutron Flux in
Experiment 41-9, ORNL-DWG-63-1936.
5. Volume Increase of 1/2-in. Beo Specimens vs Integrated Fast-Neutron Flux in
Experiment 41-8, ORNI-DWG-64-4404.
6. Experiment 41-9, Cold Pressed and Sintered BeO, ORNL-PHOTO-62909.
7. Experiment 42-9, Cold Pressed and Sintered Beo, ORNL-PHOTO-62910.
8. Irradiated Beo Single Crystals, ORNL-PHOTO-63235.
-
-
-
-
-
-
-
-
-
-
.
A
1.
ve
F
.
F
UNCLASSIFIED
ORNL-LR-DWG 71668R
EXPERIMENT NUMBER
8
-20
YUX
*
.
.
ATNA

2.
1
.14)
.
cuanto
mala
............,
(0.1)
o'i'MO'YNONYWA
.*ymGro
970
(0,1)
r
,
- REACTORÇ
T
925
1100
gw
OISYER Onni.nu.
**4444447
AAI. USIJILTOOI....
1100
H100
LAU
0
. 2.074106
7.66 x 108
4.4x107 7.33 X 106
IRRADIATION TIME (sec)
3.9 x 106
1 2 3 4 5
x 10'4/> 1 Mov)


DAMAGE FACTOR
(0) SOUND SPECIMEN
(1) FIRST CRACKS
2) GENERAL FRACTURES
(3) POWDER PRESENT
CAPSULE NO.
TEMPERATURE (°C) -
DAMAGE FACTOR II-
ORNL-44 BeO Irradiations
Fig. 1
UNCLASSIFIED
ORAL-DWG 64-8398
SOLID SYMBOLS - VOLUME INCREASE FROM
DIMENSIONAL MEASUREMENTS
OPEN SYMBOLS - VOLUME INCREASE CALCULATED
FROM LATTICE PARAMETERS
LOW DENSITY (~2.7 g/cm3)
FINE GRAIN-SIZE (~178)
LOW DENSITY (~2.7 g/cm3)
LARGE GRAIN-SIZE (~ 34 r1
A III
HIGH DENSITY (~2.9 g/cm3)
FINE GRAIN-SIZE (~2
V IV
HIGH DENSITY (~2.9 g/cm3,
LARGE GRAIN-SIZE (~ 7441
SINGLE CRYSTALS
II

T ~ 110 °C
. .
.
5
FROM DIMENSIONAL
MEASUREMENTS OF
BeO COMPACTS -
:
MEASUREMENI
.…...
•
CALCULATED FROM AVERAGE LATTICE
PARAMETER EXPANSIONS IN POWDERED
COMPACTS (21.1 AND/OR 24.0
REFLECTIONS, Cu-RADIATION) -
VOLUME INCREASE (%)
CALCULATED FROM DENSITY
MEASUREMENTS OF SINGLE CRYSTALS
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 (x1021)
FAST-NEUTRON DOSE (neutrons /cm2 , > 4 Mev)
Volume Increase of 12-in. Beo Compacts and Single Crystals vs Fast-Neutron Dose
in Experiment 44-10.
Fig. 2
Fig. 3
UNCLASSIFIED
Beo TYPE
ORNL-DWG 64-1886
LOW DENSITY ( 2.7g/cm3) HIGH DENSITY (~2.9 g/cm3)
SMALL GRAIN-SIZE (174
SMALL GRAIN-SIZE (254)
LOW DENSITY (~2.7 g/cm) HIGH DENSITY (~2.9 g/cm3)
"LARGE GRAIN -SIZE (~344) LARGE GRAIN-SIZE (744)
O NO OBSERVABLE DAMAGE
MAJOR FRACTURING
Ø MINOR FRACTURES
MAJOR FRACTURING
WITH POWDERING
BER
FAST-NEUTRON DOSE (neutrons/cm -1 Mevl že

:
1 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 40 sec 1.4 x 10 sec
7.33x10 sec 1.4x10 sec
1100°C
650°C
BeO TYPE AND TEMPERATURE
Gross Damage to BeO Specimens in Experiments 41-8 and
41-9 as a Function of the Fast:Neutron Dose and Temperature.
UNCLASSIFIED
ORNL-DWG 63-1936
• 1900 °C, LOW DENSITY (~2.7 g/cm)
o 650 °C
FINE GRAIN-SIZE (~47
• 1100 °C LOW DENSITY (~2.7 g/cm)
0 650 °C “
LARGE GRAIN-SIZE (~34 H)
• 1900 HIGH DENSITY (~2.9 g/cm)
A 650 °C" FINE GRAIN-SIZE (~25)
1400 °C ... HIGH DENSITY (~2.9 g/cm)
o 650 °C "Y LARGE GRAIN-SIZE (~74 )

I, II AND III-650 °C
VOLUME INCREASE (%)
IV-1400 °C.
To
III-1400 °C
11-1100 °C
0.4 0.8 9.2 9.6 2.0 2.4 2.8 3.2 3.6 4.0 (x1024)
INTEGRATED FAST-NEUTRON FLUX (neutrons/cm2 > 4 Mev)
Volume Increase of 12-in. BeO Specimens vs Integrated Fast-Neutron
Flux in Experiment 41-9.
Fig. 4
UNCLASSIFIED
ORNL-DWG 64-4404
LOW DENSITY (~2.7 g/cm)
FINE GRAIN-SIZE (~174)
LOW DENSITY (~ 2.7 g/cm3)
LARGE GRAIN-SIZE (~ 34 mi)
HIGH DENSITY (~2.9 g/cm3)
FINE GRAIN-SIZE (~25)
HIGH DENSITY (~2.9 g/cm3)
LARGE GRAIN-SIZE (~ 74 m)

T~ 1100°C
VOLUME INCREASE (%)
0.8 1.6 2.4 3.2 4.0 4.8 5.6 6.4 7.2
INTEGRATED FAST - NEUTRON FLUX (neutrons/cm2, >1 Mev)
Volume increase of 12-in. BeO Specimens vs Integrated
Fast - Neutron Flux in Experiment 41-8.
Fig. 5
6
.
**
..
.
*
.
-
-
-
-
-
-
*
.*
.2
:
UNCLASSIFIED
PHOTO 62909
21. O
R-15768
IRRADIATED SPECIMEN A10-63
AS POLISHED, 100X
3.92 x 1021 nut
> 4. Mev
1100 °C
O1
.18
..
Y-45349
CONTROL
AS POLISHED, 100X
DENSITY: 2.9 g/cm3
GRAIN SIZE: 234
Fig. 6
.
:
.:
.
.
.
-
.

=
2
A
n
eh
..
.
-
.
.
.
...
.
.
.
---
-
2
+
,
,
.'
.
-
.
.
*
*
.-
. -
*
N
S
-,
- .-*1-*+
-
= -_-
.
-
-
*
.
-
UNCLASSIFIED
PHOTO 62910
-
-
..

-..-
.
..
-
-..
-..
r
.
.
---
..
.-.
..
-.
--.-
: .
-
:-
1001
.
Y-45352
R-15762
AS POLISHED, 100X
AS POLISHED, 100%
DENSITY: 2.9 g/cm3
3.4 x 1024 nut
GRAIN SIZE: 704
> 4 Mev
1100 °C
CONTROL
IRRADIATED SPECIMEN A15-34
Experiment 41-9, Cold Pressed and Sintered Beo.
...........
.
.
Fig. 7
WS
-
"
-
.
W
:


o''.
...............................
.. .. .....
........... is..
.
Irradiated Beo Single Crystals.
S
Fig. 8
-
-
-
.
*
*
.55
.
mentor
.
.
12
.
'
Y
N
010
.



DATE FILMED
/ 15 165






..
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END
MNIA
TYUN
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1
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