SWRHL-46r
PARTICULATE EFFLUENT STUDY
PHOEBUS IB, EP-IV
by the
Southwestern Radiological Health Laboratory
U. S. Department of Health, Education, and Welfare
Public Health Service
Environmental Health Service
April 1970
This surveillance performed under a Memorandum of
Understanding (No. SF 54 373)
for the
U. S. ATOMIC ENERGY COMMISSION
-------
LEGAL NOT TCP:
This report was prepared as an account of Government sponsored
work. Neither the United States, nor the Atomic Energy Commission,
nor any person acting on behalf of the Commission:
A. Makes any warranty or representation, expressed or implied,
with respect to the accuracy, completeness, or usefulness of the in-
formation contained in this report, or that the use of any information,
apparatus, method, or process disclosed in this report may not in-
fringe 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 pro-
cess disclosed in this report.
As used in the above, "person acting on behalf of the Commission" in-
cludes any employee 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, dissemi-
nates, or provides access to, any information pursuant to his employ-
ment or contract with the Commission, or his employment with such
contractor.
019
-------
SWRHL-46r
PARTICULATE EFFLUENT STUDY
PHOEBUS IB, EP-IV
by the
Southwestern Radiological Health Laboratory
U. S. Department of Health, Education, and Welfare
Public Health Service
Environmental Health Service
Environmental Control Administration
Bureau of Radiological Health
April 1970
This surveillance performed under a Memorandum of
Understanding (No. SF 54 373)
for the
U. S. ATOMIC ENERGY COMMISSION
-------
ABSTRACT
The Southwestern Radiological Health Laboratory (SWRHL) of the
U. S. Public Health Service performed, under a memorandum of
understanding with the AEC, a study concerned with delineating the
physical and chemical characteristics and possible hazards asso-
ciated with release of particulate matter (greater than several
microns in diameter) from the Phoebus IB, EP-IV reactor run con-
ducted February 23, 1967. The reactor test was part of the Project
Rover Program and was conducted at Jackass Flats, Nevada.
The particle deposition occurred in a general northerly direction
from the test cell. Particles were found out to 82 miles with the
results indicating a decrease in deposition (particles/unit area) with
distance to about the 2. 5 power. The particle size distribution, of
all the particles collected, is reasonably described by a log normal
distribution with a geometric mean diameter of about 12|j. and a
geometric standard deviation of 2.1. A breakdown of the size
distribution to those particles 10|j. and above gave a geometric mean
of 26|j. and geometric standard deviation of 2.
The density of 8 particles (12 - 28fi) was found to be about 11 g/cc.
This density indicates an equivalent aerodynamic geometric mean
diameter of about 40|j. . Thus, the majority of the particles found
and studied were larger than an equivalent diameter of lOjjt - the
usual cut-off for lower respiratory tract penetration. A regression
analysis indicated a decrease in particle size and activity with
distance.
Isotopic results showed a large degree of fractionation of the fission
-------
products found in the particles.
Electron microprobe analysis indicated uranium, carbon, and
oxygen to be present in most of the particles analyzed.
Particles were transported into the off-site area. The resulting
ground concentrations were about 1 particle/100 m2 or less and there
was no known interaction of particles with people from the general
population. Thus it is concluded there was no hazard to the public
from the "particulate effluent. "
11
-------
TABLE OF CONTENTS
ABSTRACT i
TABLE OF CONTENTS iii
LIST OF TABLES iv
LIST OF FIGURES v
I. INTRODUCTION 1
II. RESULTS AND DISCUSSION 4
A. Particle Concentration with Distance 7
B. Particle Size Distribution 10
C. Radioactive Constituents of Particles 14
D. Correlation of Particle Size, Gross Activity and
Distance 17
E. Elemental and Chemical Composition 22
F. Particle Density 27
G. Biological Clearance Rates 28
III. SUMMARY AND CONCLUSIONS 30
REFERENCES 34
APPENDICES
DISTRIBUTION
111
-------
LIST OF TABLES
Table 1. Particle size distribution 14
Table 2. Results of isotopic analysis of particles (pCi) 16
Table 3. Correlations of size, activity and distance 18
Table 4. Results of electron microprobe analysis 24
Table 5. Location, size, and total isotopic activity of
particles 26
Table 6. Density of particles 28
IV
-------
LIST OF FIGURES
Figure 1. Particle sampling areas. 5
Figure 2. Reactor Test ground deposition pattern for
Phoebus IB, EP-IV, 24 February 1967. 6
Figure 3. Hodograph for Jackass Flats, Phoebus IB,
EP-IV. , 8
Figure 4. Number of particles per 100m2 versus distance
(miles). 9
Figure 5. Particle size distribution, Phoebus IB, EP-IV. 11
Figure 6. Log probability plot of 109 particles (size in
microns). 12
Figure 7 Particle size versus distance from test cell. 20
Figure 8. Survey meter readings of particles versus
distance from test cell (beta + gamma with G.M.
instrument). 21
Figure 9. Estimated downwind transport distance for
various size particles. 23
-------
I. INTRODUCTION
Project Rover reactor tests are conducted at the Nuclear Rocket
Development Station (NRDS), Jackass Flats, Nevada.* The station
is about 90 miles NE of Las Vegas, Nevada.
The Project Rover reactors are based on a single pass gas-cooled
design. The reactor cores are composed of annular fuel rods made
up of UC beads in a graphite matrix. The coolant, hydrogen, is
passed through the core and expelled to the environment via the
reactor nozzle. The hydrogen is burned after exiting from the
reactor and this thermal energy, plus the effluent kinetic and
thermal energy, produces a cloud or effluent rise of better than
1500 meters.
It has been noted over a period of several years that the effluent
from Project Rover reactor runs contains large radioactive par-
ticulate matter in addition to gaseous and normal atmospheric size
particulate matter. The large particulate matter is composed of
actual segments of the reactor core released by what is termed the
"corrosion process," whereas the radioactive gaseous effluent
results from diffusion of the fission products in the core. The
particles can contain fission product inventories up to the order of
microcuries in quantity. Several of the particles were detected
30 miles downwind of the test cell after the NRX-A5, EP-IV test
on June 23, 1966 (1400 - 1430 PDT). This discovery, coupled with
*The Project Rover Program is charged with development of a
nuclear reactor for rocket propulsion for deep space exploration.
The program is administered by SNPO, the Space Nuclear
Propulsion Office.
-------
increasing reactor power, caused concern about the possible
6
hazards associated with the deposition of particles in populated areas.
The physical harm from interaction of these particles with individuals
is not fully understood. Areas of possible concern are skin, eye,
and lung doses. This report is concerned primarily with determining
the physical parameters of the effluent versus other studies concerned
with their biological interaction.
This report presents the results of particle studies for the Phoebus IB
test series, Experimental Plan IV conducted by the Southwestern
i
Radiological Health Laboratory. * It supersedes our previous
reports on the subject. The event was conducted at_1400 PDT on
February 23, 1967, at Test Cell C, NRDS. The reactor was in the
inverted position, with the effluent expelled vertically upward. The
power integral was about 3 x 106 Mw-sec with 30 minutes
(1400-1430 PST) at full power, 1500 Mw. The work reported here
was performed under a memorandum of understanding between the
Public Health Service and the Atomic Energy Commission who are
responsible for off-site safety. Effluent from the reactor test was
distributed in a general northerly direction. Particles were found
up to 82 miles from the reactor.
Project Objectives
The general objectives of the SWRHL studies were to determine the
extent of downwind deposition of particles and their chemical and
physical characteristics. Specifically the objectives were to de-
termine an indication of the following:
A. Downwind concentration of the particles on the ground as
*The Phoebus IB test series was conducted by the Los Alamos
Scientific Laboratory as part of the reactor development program
for Project Rover.
-------
a function of distance from the test cell. The prime
emphasis was on downwind instead of crosswind
concentrations.
B. Particle size distribution for all of the particles and for
various distances downwind.
C. Constituent radioactive composition of the particles:
1. Gross alpha, beta, and gamma.
2. Specific isotopic composition - including the
isotopic fractionation.
D. Correlation of the parameters: particle size, activity.
and distance of collection.
E. Elemental and chemical composition.
F. Particle density.
G. Possible hazard to the general population in the off-site
area.
After collection of the particles, a few were used in a study of
biological clearance rates in rats. The primary objective of the
study was to develop methodology for future studies.
-------
II. RESULTS AND DISCUSSION
During a six-day period after the reactor test, 53 areas, generally
300 ft2 or more in area, were surveyed for particles using an open
window E-500B survey instrument held about 6 inches above the
ground (see Appendix A for methods). The areas surveyed were in
a northerly direction from Test Cell C at distances between 9 and
115 miles. The sampling locations were chosen on the basis of
particle survey results, vegetation profiles, tracking by aircraft,
and to some extent by terrain features.
Particles were located in 21 of the monitored areas and 228 indica-
tions of particles were obtained. * This information is presented in
Figure 1 and Appendix B. The general effluent hotline, based on
three arcs where vegetation samples were collected (two on-site
and one on Highways 6 and 25) and the area of highest air concen-
tration (according to air samples taken along Highway 25), is also
indicated in Figure 1. Specific results for air and vegetation
samples are given in Reference 1.
Figure 2 indicates the fallout deposition pattern determined by
Edgerton, Germeshausen and Grier, Inc. on February 24. The
pattern was determined using a calibrated crystal in an airplane
flying at about 500 feet above the surface.
^Effluent from reactor cool-down was carried by the night-time
drainage winds over the Lathrop Wells area (approximate azimuth
210°). This area, along Highway 95, was monitored on February 27
and there was no indication of particulate activity.
-------
Warm Springs
Vegetation Arc - O
Tonopah to Coyote Summit
35O
Approximate Hotline
(As determined by
vegetation samples)
-N-
1O
MILES
Phoebus 1B EP IV
Reactor Test
Discussed on page A
Locations surveyed
for particles. Number
indicates particles found
normalized to 1OO m2.
Vegetation Arcs
Beatty
Highest A
Sample Result
Queen City
Summit
Yucca A.S.
Test Cell "C"
Figure 1. Particle sampling areas.
-------
NOTE: Dose rates shown
are net increase above
background.
Isodose Contours
(measured)
Isodose Contours
(interpolated)
Aircraft Flight
Path
Site
JACKASS FLATS
.04 MR/HR
O4-.O8 MR/HR
.O8-.12 MR/HR
.12-.2O MR/HR
2O-.28 MR/HR
.2S-.4 MR/HR
.4-1 MR/HR
1-2 MR/HR
2-4 MR/HR
4-5 MR/HR
Figure 2. Reactor Test ground deposition pattern for Phoebus IB, EP-IV
24 February 1967. Discussed on Page 4.
-------
A comparison of Figures 1 and 2 shows that the particle ground
survey was generally performed in the area of highest deposition.
Thus, although the ground survey primarily determined the down-
wind distribution rather than both downwind and crosswind, it is
felt that it should be reasonably representative of the particle
hotline. An exception is the points at less than about 25 miles from
the test cell, where our surveys appear to be generally east of the
hotline. A composite of the studies indicates the debris hotline
1O*3
was on an azimuth between 5 - 10 . ' ' It appeared to start
NNE and "back" more northerly with distance. Using ESSA/ARL
upper level weather data (radar) collected at 1430 on February 23, 1967,
over Jackass Flats, Nevada, an attempt was made to determine the
initial height attained by the particles. The hodograph (Figure 3)
shows that a particle hotline of 7 would correspond to an effective
release height of 10, 500 feet MSL and mean layer wind speed of
about 12 mph.
A. Particle Concentration with Distance
The number of particles detected on the ground per 100m2 as a
function of distance is presented in Figure 4. The indicated line
is based on regression or least squares analysis of the data
(log-log). Only those sampling points near the hotline (as
indicated by this study, the Pan American study, and other
effluent studies) were used in this analysis. Fourteen of the
21 sampling points were used. The slope of the line is -2. 5 and
the correlation coefficient for the indicated line is -0.95 or
between -0.83 and -0.98 at the 95% confidence level. *
#The correlation coefficient squared is an indication of the percent
of the variation of the data explained by the regression line.
-------
DATA FROM ESSA/ARL
23 FEB 67
(3430 MSL) 1415
Vector Plot of Winds by 1OOO ft.
Height Increments
Discussed on Page 7
1O.5
Indicates 8.5 x 1O3 ft. MSL
19O/16
8.5,
190/13
Indicates 19O° Azimuth at 13
Knots Between 7.5-8.5 x 1O3 ft. MSL
7.5
17O/13
6.5
160/O7
5.5
22O/O8
Figure 3. Hodograph for Jackass Flats, Phoebus IB, EP-IV.
-------
o
o
^
o:
UJ
Q.
in
UJ
_l
y
h
ir
<
Q.
PHOEBUS 1B EP IV
(Based on 14 Selected Plots
Near the Hot Line )
Discussed on Page 7
10'
102
DISTANCE (miles)
Figure 4. Number of particles per 100m2 versus distance (miles).
9
-------
B. Particle Size Distribution
The size frequency distribution for 109 of the particles js pre-
sented as a bar graph in Figure 5 (numerical information in
Appendix C). This information is also presented on log proba-
bility paper in Figure 6. It appears to give a reasonable fit to
a log normal distribution with a geometric mean of about 12u .
The goodness of fit for this distribution was checked using a
Chi(X) squared test. The calculated value of X2 (95% confidence
level) for 6 degrees of freedom was 8.9. Thus the data appear
to be reasonably described by a log normal distribution. But,
Figure 6 gives some indication of a platykurtic bimodal distribu-
tion.
The bimodal characteristic of the curve could be due to the
presence of two or more distributions. That is, a basic distri-
bution of fairly large particles and a distribution formed from
fractured particles. If this is the case, it is felt that the fractu-
ring took place in the environment.
It should be emphasized that correlations of the data may be
biased by collection techniques (easier to find more active and
thus possibly larger particles, collection was over a period of
time, etc.); terrain features; and especially the fragile nature
of the particles which made them very susceptible to fracturing
during transport, collection, and analysis. Therefore it is
possible that some of the particles were reduced in size, thus
affecting any correlations. Care was taken in collection and
handling (see Appendix A for methods) in an attempt to minimize
these effects. If several particles were found in one sample,
they were assumed to be parts of a fractured particle and ex-
cluded from the sizing analysis. Particles were collected with
10
-------
16
14
12
UJ
O
Z
UJ 1O
£
D
O
O
O
8
0
Z
UJ
D
a
UJ 6
u.
4
2
O
— —
—
_
^~
—
—
—
O 2 4 6
I
8 1O 12
I
14
16
I
18 2O
I
22
I I
,111
1
1 1 1
1 1
1 1
8.6% > 5O microns
Discussed on Page 1O
II, < ,
24 26 28 3O 32
1 1
34 36 38 4O 42 44
III
46 48
_
—
^
^~
—
—
—
—
—
—
5O 52
PARTICLE SIZE (microns)
Figure 5. Particle size distribution, Phoebus IB, EP-IV.
-------
102
c
o
L-
O
£
^^
u
N
(/)
iiJ
_l
O
h
10'
PHOEBUS 1B EP IV
Discussed on Page 1O
J L
1O 2O 3O 4O 5O 6O 7O
FREQUENCY (percent)
80
9O
95
Figure 6. Log probability plot of 109 particles (size in microns).
12
-------
a small amount of extraneous material and were handled with
minimum contact in the laboratory, i. e., sieve techniques, etc.,
were not used.
It is worth emphasizing the following points:
1. A measured area was surveyed at each location. The survey
was performed using a survey meter and traversing the area at
one-foot intervals or less with the probe 6 inches or less from
the ground. All indications of particles were noted. Of a total
of 228 indications, about 180 particles were collected, 170 from
monitored locations, 10 close-in where particles per unit area
were not determined. Of those picked up, about 15 were used
in developing techniques and are thus not reported in the sizing
results. Of the remaining 165 particles, 56 were noted to be
fractured during sizing and thus not used in analysis of size.
It is felt that the reduction from the original 165 to 109 for
sizing occurred in a random manner. Where all the particles
located in the measured area were not picked up, the choice
was for the "hotter" ones.
2. A cut-off in size (such as 10|o.) was not used. That is, the actual
size of all the particles was determined and reported.
3. Even if the 65 unsized particles were included and were considered
to be above the geometric mean determined (12|j.), the new
geometric mean would be less than 20(0, .
Table 1 gives a subdivision of the particles into several categories
based on size and the distance at which the particles were collected.
13
-------
Table 1. Particle size distribution(microns).
Category
All particles;
at all distances
Particles > lOfj.
at all distances
All particles;
10 miles
Particles > 10(j.
< 10 miles
Particles > 10|JL
22-39 miles
All particles;
39-82 miles
Particles > lOu-
39 miles
No. of
Particles in
Category
109
59
43
28
13
17
9
Geometric
Mean
Diameter
12.2
25.7
14. 1
34.7
18.7
11.4
22
Geometric
Standard
Deviation
2.7
1.9
3.2
2.0
1.8
« M «
...
This breakdown into various size categories makes the results more
analogous to those of other study groups (Pan American and
Los Alamos Scientific Laboratory) which were based on analysis of
particles greater than 10 - 15(j. in diameter. '
C. Radioactive Constituents of Particles
Radiometric measurements were made on the particles to
determine beta plus gamma activity (open window GM probe),
alpha activity, and specific nuclides. The various radiometric
measurements were not all made on the same particles, there-
fore, they are not necessarily related.
The beta plus gamma activity (GM probe) of 78 particles, along
with their size (Feret diameter), is given in Appendix D. The
distance downwind from the reactor, where they were found, is
also indicated. This gross activity is only a relative number,
and is reported as counts per minute detected by the GM probe at
14
-------
time of count. The particles were all counted at about the same
time (5 days after the event). The probe used has an approximate
efficiency of about 10% for beta and less than 1% for gamma
activity.
The alpha activity of eleven of the particles was measured on a
NMC PC-3B counter and ranged from approximately 0. 1 to
28 pCi/particle with an average of 8 pCi/particle.
The specific isotope analysis, based on gamma spectroscopy
using aNal(Tl) 4-by 4-inch crystal, for a number of particles is
indicated in Table 2. Several particles were analyzed on a
germanium (Li) detector. The germanium detector was not
calibrated for quantitative analysis, thus the results were used
only to help confirm the "Nal analysis. "
The results in Table 2 are based on hand analysis by the Compton
subtraction method, including the use of half-life verification,
of the gamma spectra. In some of the samples reported in
Table 2, more than one active particle was found. In these cases
it is not known whether each particle was deposited separately
or if they resulted from a single particle which was fractured
by handling, but the latter appears more likely. In addition to
the results in Table 2, the spectrum from the germanium
detector indicated the presence of 31 Th (daughter product of
235 U). Short half-life isotopes noted to be present, but not
quantitated were 91Sr, 9Z Sr, 92 Y and 135I. Other fission
products were undoubtedly present, but below the level of detecta-
bility. A least squares spectrum stripping computer program
was used to analyze 14 of the particles. The results were similar
to those in Table 2.
15
-------
Table 2. Results of isotopic analysis of particles (pCi)
Sample
No . '• •:
95 Zr
97 Zr
99 Mo
103Ru
132 Te
13JI
140Ba
141Ce
143Ce
147 Nd
2"Np
Total
20528
A
ND
ND
S4.000 110
ND
8, 200 7
ND
150,000 110
78,000 67
ND
ND
ND
320,00') 290
B
ND
ND
, 000
ND
, 500
ND
, 000
, 000
ND
ND
ND
,000
A
2, 500
240, 000
12,000
ND
3, 000
ND
1,600
2,800
8, 500
3, 000
51, 000
320, 000
ffll.Sr '2 Si
20540
B
15, 000
ND
18, 000
5, 500
8, 000
ND
15, 000
210, 000
7, 100
26, 000
470, 000
770, 000
• 92 7 . 97 7.
c
110, 000
8, 600, 000
540, 000
ND
71, 000
ND
60, 000
100, 000
280, 000
210, 000
1, 300, 000
1 1, 000, 000
r 9'Mo 132T
20542
A
1, 100
B
2, 000
93,000 180,000
1,700
ND
1, 100
ND
2, 200
1, 500
3,400
1,800
10, 000
120, 000 2
135, 140B,
6, 200
1, 100
3, 000
ND
4, 900
3, 300
8, 200
5, 000
35, 000
50, 000
141 CP
20543
12,000
1, 900, 000
280, 000
2, 000
2, 600
1, 000
ND
300
2, 500
ND
ND
2, 200, 000
143 OP 147Nri
20544
18, 000
1, 100, 000
180, 000
ND
12, 000
ND
24, 000
240, 000
61, 000
47,000
120, 000
1, 800, 000
239Nn
A
3, 500
330,000
4, 500
6, 300
4,400
ND
7,400
5, 500
14,000
6, 500
50, 000
430, 000
20545
B
5, 300
880,000 2,
11, 000
24, 000
3, 700
ND
20, 000
17, 000
11,000
8, 300
120, 000
1, 100, 000 2,
C
18, 000
000,000
350, 000
ND
8,700
ND
81, 000
27,000
82, 000
31, 000
210,000
800, 000
D
23,000
2, 100, 000
74, 000
55,000
16, 000
ND
60, 000
53, 000
92, 000
57,000
220, 000
2,800, 000
20546
34,000
2, 600, 000
88,000
ND
16, 000
ND
64, 000
9, 600
110,000
61, 000
180,000
3, 200, 000
pie #20623-1- Indications of 95Zr, 97Zr, 99Mo, 140Ba, UICe, 14JCe, 147Nd, 239Np
pie #20623-2- Indications of 95Zr, 97 Zr, 99Mo, 140Ba, 141Ce, 143Ce, l47Nd, 239Np
rapolated to 1515 PST, February 23, 1967
phabetic letters (A, B, etc.) indicate a subdivision of the sample
- Not detectable
-------
Comparison of the results in Table 2 shows that the two
portions of sample 20528 have similar inventories of fission
products and are dissimilar to all other samples, indicating
that they did result from fractionation of a single particle (note
page 32, microprobe analysis indicated a possible difference.)
The similarity in inventories of 20540-A and C indicate the
same; however, 20540-B is unlike A and C, which would tend to
show that this was not a part of the original particle or that the
original particle may have been a combination of several types
of material. This might be explainable by a combination of
reactor material (UC_ and/or graphite) and environmental dust.
The gamma spectra from 20542-A and B indicate that these
probably originated from one particle. Inspection of 20545
indicates that portions A, B and D are similar, but that portion
C is different. Because of the low density of particles on the
ground, it is difficult to conceive of more than one particle being
picked up in a sample (taken from an area of about one square
inch). Thus, the hypothesis of heterogeneous particle compo-
sition is presented.
Radioisotope analysis indicated a significant amount of fraction-
ation (discussed in Appendix F).
D. Correlation of Particle Size, Gross Activity and Distance
A number of attempts were made to correlate the parameters of
particle size, gross activity and distance.
Both regression analysis and correlation coefficients were used
on various transforms of the data (linear, log linear, and log log).
The results of the various correlation attempts are given in
Appendix E. The correlations best justified by theory are given
in Table 3. The premises used were:
1. Regression is generally used where one of the variables is
17
-------
Type
Data Correlation
Size and
Distance^
Activity2
and Distance
Activity
and Size
Log Log
Log Log
Log Log
Linear
Number of
Data Points
6
6
68
68
Slope of Correlation
Line4 Coefficient
-0.2 -0.641
(See Fig.
-0.4 -0.711
(See Fig.
-0. 171
-0.46
7)
8)
1. Not significantly different from zero at the 95% confidence level.
2. Radioactivity as determined by a GM probe.
3. Distance from test cell at which particle was found.
4. Parameter = •f (Distance)11 where n is reported slope.
assumed to vary with the other, i. e. , size with distance.
Correlation coefficients are applicable for two variables
which are both random, but are assumed to vary together,
e.g., size and activity. The correlation coefficient may
also be used to test the goodness of fit of a regression line.
That is, the correlation coefficient squared is the fraction
of variance in the data explained by the regression line.
2. The log log correlations are reported because the variables
are assumed to be related by power functions, e.g. , activity
is a function of the surface area (r2) and the volume (r3) of
the particle and the distance traveled is a function of termi-
nal settling velocity(r 2). Thus a log log plot would be a
straight line where graphs of other functions of the data would
be expected to be curves.
3. The particle size and activity are described by a distribution
rather than a precise value at each distance. Thus, the
geometric mean of size and activity for various distance
increments was used in the correlation attempts. The
18
-------
geometric average size and activity were determined for
the distance intervals: 7, 9, 22-26, 29-34, 39-44, and
51-82 miles. The separation into intervals was necessary
to obtain a reasonable number of particles for each distance.
The averages were then plotted at an average distance
(weighted by number of particles at the various distances).
The geometric mean for particle size is plotted versus distance
in Figure 7- The line is based on a regression analysis. The
correlation coefficient for the indicated size with distance
relation (mean size = distance to the minus 0. 2 power) is -0. 64.
Due in part to the small number of points used in the correlation,
this is not significantly different from zero at the 95% confidence
level, but although the precise relation is in doubt, there appears
to be a relationship between size and distance.
The correlation coefficient for the regression line (Figure 8) for
activity of particle versus distance is -0.71. This indicates a
reasonable fit of the data, but due to the limited number of points,
it is not significantly different from zero at the 95% confidence
level. However, it definitely suggests a decrease in activity
with distance.
It is difficult to explain the correlations of activity (P + Y) with
size. The activity should be a function of the area or volume of
the particle (radius squared or cubed), so a log log plot should
give the best straight line. However, the linear relationship is
stronger than the log log relationship. Thus, they are both
reported in Table 3. This may in part be due to the use of a
GM probe for the radioactivity measurement. Beta and gamma
efficiency for the probe, resolving time (about 10% or more),
and energy dependence were not considered.
19
-------
102
-------
101
I-
u
<
UJ
_l
o
h
g
<
Q.
UJ
UJ
10°
1O
i—i—rrr
T—I—T~TT
PHOEBUS 1B EP IV
Discussed on Page i g
SLOPE = -O.4
CORRELATION COEFF. = -O.7
J III!
10'
DISTANCE FROM TEST CELL (miles)
102
Figure 8. Survey meter readings of particles versus distance from test cell
(beta + gamma with G.M. instrument).
21
-------
Figure 9 gives an indication of the distance downwind ve
size particles can be transported. The figure is based on:
1. Stokes1 Law settling velocity.
2. Release height of one mile, i. e. , difference between release
height and ground level at point of deposition.
3. Wind or transport speed of 15 mph.
Atmospheric diffusion or turbulence was not considered, but
would primarily cause the deposition to be spread (distance
plus and minus) around the indicated transport distance.
E. Elemental and Chemical Composition
A number of samples were analyzed with an electron micro-
probe to determine their elemental and chemical composition.
All the particles were not analyzed, but those selected should
be generally representative of most of the particles collected.
These results are given in Table 4 and the general sample de-
scription is given in Table 5.
Three particles were analyzed for quantitative results. Quanti-
tative analyses of one bead yielded the following results:
Element Percent by Weight
Uranium 91.0
Carbon 8.4
Oxygen 0.7
The other results were similar, i.e. , + 10% of the given value.
These elemental fractions indicate a stoichiometric composition
of about 90% of uranium as UC and about 10% or less as UO
^ 2
One particle was analyzed by X-ray diffraction subsequent to
microprobe analysis (U, C, and O). The particle was removed
22
-------
102
Basis: 15 mile per hour wind speed.
Stokes' Settling Velocity for
Streamline Motion
Lines: A. Center Line
Release height 1 mile above terrain.
Particle density of 11 g/cm3
B. Center Line
Release height 1 mile above terrain.
Particle density of 5 g/cm3
C. Center Line
Release height % mile above terrain.
Particle density of 11 g/cm3
J I I L_L
10'
DISTANCE FROM TEST CELL (miles)
Figure 9- Estimated downwind transport distance for various size particles,
Discussed on page 22.
23
-------
Table 4. Results of electron microprobe analysis
Sample No. *
Microprobe Results
Comments
20528-A
20528-B
20540-A
20540-B
20542-A
20542-B
20543
20544
20545-A
No detectable U, Zr, Mo, Nb
4 hot spots on this sample
(1) Contained U and C
No detectable Zr, Mo,
Nb or O
(2) Contained U and C
Indications of traces of
Nb and O
No detectable Zr or Mo
(3) Contained U and C
No detectable Zr, Mo,
or Nb
(4) Contained U and C
No detectable Zr, Mo,
or Nb
No detectable U, Zr, Mo, or
Nb
Silicate matrix, disintegrated
under electron beam.
Particle lost in transfer
No detectable U, Zr, Mo, or
Nb
Contained U and C
Indications of trace of Nb
Contained U and C on silica
matrix
Sample could not be analyzed
because the activity was on a
large grain of sand.
Radionuclide anal-
ysis indicated A &
B were similar.
Radionuclide anal-
ysis noted dissimi-
larity.
Radionuclide anal-
ysis similar for
A & B.
Radionuclide anal-
ysis noted A & B to
be similar, but C to
be different from
A & B.
24
-------
Table 4. Results of electron microprobe analysis (continued)
Sample No. * Microprobe Results Comments
20545-BContained U, C, and O
No detectable Zr, Mo,
or Nb
20545-C No detectable U, Zr, Mo,
or NB
Contained U, C and O
Contained U, C and O
Contained U, C and O
*See Table 5 for collection location, size and gross activity.
25
-------
Table 5. Location, size, and total isotopic activity of particles
N)
Sample No.
20528
20540
20542
20543
20544
20545
20546
20623
Azimuth -Distance
357°
3°
16°
16°
12°
13°
13°
9°
6.
21.
25.
25.
23.
23.
23.
72.
0 mi
5 mi
0 mi
0 mi
5 mi
0 mi
0 mi
0 mi
Size (p. ) Activity*
45 x 32** 610,
16 12,000,
2x3
20 x 24 370,
19 x 24
9 x 14 2, 200,
1,800,
7,100,
3, 200,
15
(PCi)
000
000
000
000
000
000
000
Comments
Many <
One 25
One on
Several
One on
6n
x 20|j.
a grain of sand
grain of sand
>25 active pieces
:'':Total identified activity to two significant figures. See Table 2 for specific isotopic activity.
## The two figures indicate the dimensions of the particle as seen in a plane view. A single
figure indicates uniform dimensions.
-------
from its mounting with a micro-manipulator causing it to fracture.
A fragment of the original particle of approximately eight microns
in diameter was mounted on a pyrex glass fiber and placed in a
Debye-Scherrer powder camera. Forty-foui1 hours of exposure
produced very faint but readable diffraction lines. The relative
line intensities could not be measured; however, line positions
were determined. The diffraction pattern of the sample was
directly compared with those from a reactor bead and spectro-
graphic grade carbon. The diffraction analysis indicated only
uranium carbide and free carbon to be present. Uranium oxide
would not be detected in this particular analysis because of the
low concentration of uranium oxide in the sample and the small
sample size.
The free carbon that was indicated in the diffraction analysis is
probably due to carbon deposition on the sample during the micro-
probe analysis. Correlation of these analyses indicated that the
particle was composed of UC, and a form of uranium oxide. The
L*
uranium oxide was probably UO .
F. Particle Density
Density determinations were made on 8 particles (see table 6).
The arithmetic mean density (also geometric mean) was
11 gm/cm3. The determination was based on the equivalent
diameter (based on two dimensional projection of a spherical
particle of equal cross sectional area) and Stokes1 settling
velocity in hexane. The method Is further described in Appendix A.
27
-------
Table 6. Density of particles
Equivalent Diameter
(n)
28
25
20
18
22
20
12
20
Density
(gm/cc)
9.59
13.20
9.79
11.56
11.53
12.88
11.43
8. 11
G. Biological Clearance Rates
A study was performed to estimate the clearance rate in rats
for particles collected from the reactor run. The objectives
were as follows:
Primary - Establish methodology for future studies.
Secondary - Obtain an indication of clearance times and routes
and the solubility of the radioactivity associated
with the particles.
Due to the limited number of radioactive particulates available
for this study, only two rats were injected; one intratracheally and
the other intraesophageally. Particulates with a CMD*of less
than 10n were suspended in an aqueous solution and 0. 15 ml of the
suspension was injected into the trachea (lungs) of one rat and
into the esophagus (stomach) of the other rat.
Clearance from the animal injected by the intraesophageal route
(stomach) was rapid. Thirty-five percent of the original body
burden cleared in the first 24-hour period and an additional
*Count mean diameter.
28
-------
fifty-eight percent of the original burden cleared in the second
24-hour period. The amount remaining after the fifth day was
insignificant.
Clearance was much slower and relatively constant for the
animal injected by the intratracheal route. A clearance half-
time of approximately 20 days was calculated for this animal
with over 10 percent of the original body burden still remaining
66 days following injection of the radioactive material. This
animal is still under observation and will be permitted to expire
naturally. The results indicate that these particulates were
relatively insoluble since essentially all the radioactivity lost
in both rats was accounted for in the feces.
29
-------
III. SUMMARY AND CONCLUSIONS
The objectives of the program were intentionally limited so that a
reasonable degree of success could be accomplished with available
personnel and financial resources. Thus, although there is reasonable
doubt remaining concerning some of particle parameters and many
questions to be answered or investigated more fully in the future,
it is felt the objectives outlined in Section 1 - B were met.
Post-run inspections of the reactor cores have shown varying types
of corrosion both with type of reactor, i. e. , Phoebus or NRX (KIWI),
and with reactors within a type, i.e. , NRX-A4 or A5. Thus, knowledge
of the parameters of particles in the effluent from a given reactor
test may not be directly applicable to other reactor tests.
It should be reiterated that this report, and therefore the conclusions
drawn from it, are based on a limited amount of information. Thus,
the following observations should be used with discretion and should
be validated with future reactor tests.
Observations
A. A least squares fit of the data indicated that the particle concen-
tration per unit area on the ground decreased with distance to
about the 2. 5 power (Figure 4, page 13). In addition to indicating
the change with distance, an estimate of particle concentration on
the hotline is indicated. There was very little wind shear for
the Phoebus IB, EP-IV, and a moderate wind speed. Thus the
figure should give a reasonable indication for reactor runs of
this type in the future (same power, power integral, and fuel
type).
30
-------
B. The average particle size and activity decreased with distance.
The data'are insufficient to denote a definite relationship, but
indicate the decrease with distance is less than distance to the
first power (see Figures 7 and 8).
C. The overall size distribution of the particles collected from
6 to 82 miles (based on sizing 109 particles) gave a reasonable
fit to a log normal distribution. This distribution had a geo-
metric mean of 12u and geometric standard deviation of 2. 7. A
breakdown of the distribution into those particles equal to or
greater than 10(0. collected at less than 10 miles gave a geometric
mean of 35(0. with a geometric standard deviation of 2.
D. Based on the average density for eight particles (11 g/cc - which
may not be representative of all particles) and the considerations
of aerodynamic diameter, greater than 90% of the particles
detected were above an aerodynamic diameter of 10(j. which is
usually considered the upper size level for penetration into the
respiratory system. This statement holds for all downwind
distances where particles were detected. Admittedly insufficient
particles were detected to determine more than an indication of
particle size with distance, especially beyond 50 miles.
E. Based on eleven randomly selected particles analyzed for elemen-
tal composition it is concluded that the particles collected were
primarily uranium and carbon. The density results also indicate
the particles are largely uranium.. It is suggested, based on
other reports *» ' that the particles might fall into two types
of distributions, i.e., large particles around 100(j. maybe UC~
with associated graphite coat and possibly natural environmental
material, and the small particles primarily UC?. Some of the
31
-------
particles were noted to be small UC, particles associated with
silicate material (material from the natural environment).
F. There appears to be a "weathering" effect in detecting and col-
lecting the particles. The particles collected beyond 40 miles
from the test cell were primarily collected on the 26th or 2 to
3 days after the near-in collections. From Figure 7 it can be
noted that particle size did not decrease as much with distance
as might be expected (based on Stokes1 law). This could be
explained if the small particles were no longer detectable at the
time of survey. Also (Figure 4) the observed particle concen-
tration on the ground fell off slightly faster than might be ex-
pected. This would follow the previous reasoning in that the
small particles were not detected, at least not with the same
efficiency as the larger particles, at the later survey times.
G. As can be noted from Figures 1 and 2, particles were deposited
in the off-site area (out to 82 miles from the test cell). But,
the deposition density was of the magnitude of 1 per 100m2 and
was in areas of very low population density. The only people in
an area of known deposition were at Diablo (3 people). There
was no known case where the general population came in contact
with this effluent.
H. Due to the variation in distance to the off-site boundary and
variation in population density in the off-site area, it is difficult
to assess the potential hazards from these particles. This
would be true even if the hazard resulting from human interaction
with the particles was known; which is not the case. With the
unknowns, it becomes impossible to make a definitive statement
at this time concerning the hazard in the off-site area. Among
32
-------
the statements that can be made concerning the potential
hazard of these particles are:
1. Particles were transported to 82 miles.
2. The ground density of the particles and thus the probability
of human interaction (disregarding population densities)
decreases with distance to about the 2. 5 power.
3. The particles contain microcurie quantities of fission products,
4. The biological half-life in the lung may be very long.
-33
-------
REFERENCES
1. "Preliminary Report of Off-Site Surveillance for the
Phoebus-IB Test Series," Public Health Service, Southwestern
Radiological Health Laboratory, March 9, 1967.
2. "Phoebus IB, EP-IV Effluent and Ground Deposition Surveys,"
EG&G, Inc.; 21 April 1967; EG&G 1183-1321.
3. Van Vleck, L. D. , "Summary of Results,Effluent Monitoring,
Phoebus IB, EP-IV, " PAA 33-12, 19 July 1967.
4. Bolles, R. C. and Ballou, N. E. , "Calculated Activities and
Abundances of 235U Fission Products," USNRDL-456.
5. Altomare, P. M. and Coleman, J. R. ; "Study of Particulate
Effluent from Nuclear Rocket Engine Test." Part 1, NUS
Corporation, September 1967.
6. McNelis, D. N. , Memo to Dr. D. S. Earth, Chief, BER,
SWRHL, on 10/18/66.
34
-------
APPENDICES
APPENDIX A. METHODS OF COLLECTION AND ANALYSIS 35
APPENDIX B. PARTICLE SURVEY RESULTS 41
APPENDIX C. FREQUENCY OF PARTICLE SIZE 44
APPENDIX D. SURVEY METER READINGS OF PARTICLES 46
APPENDIX E. PARTICLE SIZE, ACTIVITY AND DISTANCE
CORRELATION COEFFICIENTS 48
APPENDIX F. ISOTOPIC FRACTIONATION 49
-------
APPENDIX A
METHODS OF COLLECTION AND ANALYSIS
A. Particle Collection
Particles were located by monitoring teams surveying either an
area of 300 square feet or 100 square meters (except as noted
in Table 1) with an Eberline E-500B Geiger counter with the
shield open (beta plus gamma) and/or a Precision 111 "Scintil-
lator." The general area to be surveyed was determined from
the results of aerial cloud tracking, gamma exposure measure-
ments during cloud passage, and gross gamma counting of
vegetation results from two on-site vegetation arcs and an arc off-
site on Highway 25 (Figure 1). Collection took place over a six-
day period. The surveys were performed along a downwind
sector from about 350° to 30° and between 9 and 115 miles.
Fifty-three areas were surveyed (see Figure 1). Particles were
collected with as little soil as possible. It is felt that the col-
lection techniques were reasonably good, but by no means
absolute. Out of the 228 indications for particles, about 170 par-
ticles were picked up (no attempt was made to pick up all of them).
Where all the particles were not picked up, the "hotter" ones
were selected. Various numbers of these particles were then
used in the different analyses.
One particle was collected by impaction on sticky material placed
on the leading wing edge of the PHS sampling aircraft. The
location of collection of the particle could not be defined because of
the method of collection.
35
-------
The particles were isolated from the sampled material, usirig
microscopy, autoradiography, and collimated PA detectors.
They were fixed on glass slides with polyvinyl chloride (PVC)
or saran film. After fixing on the slide, particles were auto-
radiographed (except for 5 of them) to determine which was the
actual particle. In some samples more than one particle was
found. The particles were extremely fragile and so in these
cases it is not known whether samples were fractured through
handling or were deposited as several particles. When more
than one particle was noted in the sample, it was excluded from
the sizing results. Less than 1/3 of the particles sized were
excluded because of fracturing.
B. Particle Sizing
The diameter was determined using the Feret diameter measure-
ment. A qualitative determination to establish that the third
dimension was of the same regularity as the other two was made
by focusing alternately on the topmost portion of the particle and
on its lowest maximum dimension. The particle dimensions
were irregular, but were more spherical than "needle like."
C. Constituent Radioactivity of the Particles
Three types of radiometric measurements were performed.
They are as follows:
1. Gross (3 + \ - Particles were counted approximately 5 days
after collection using a RM-3A GM (open window) detector.
The detector was not calibrated, but probably has about 10%
and less than 1% overall efficiency respectively for beta and
gamma. Results are given in CPM at time of count.
36
-------
2. Alpha Activity - Alpha activity was measured on an
NMC PC-3B counter. Eleven particles were analyzed.
Activity is reported in pCi/particle as of time of count. No
correction was made for self-absorption. Thus, in reality,
the activity reported is probably surface activity rather than
total particle activity.
3. Specific Isotope Analysis - Quantitative specific isotope
analysis was performed by gamma spectroscopy. Spectra were ob-
tained by using a 4- by 4-inch Nal(Tl) crystal, a 4-inch photo-multi-
plier, and 200 channels of a 400-channel pulse height analyzer.
Analysis was performed from 0-2 MeV at 10 keV per
channel. Spectra from a lithium-drifted germanium diode
detector in connection with a 1024 channel analyzer were
used in analysis but were not quantitated due to lack of
qualitative calibration of the instrument.
These results were analyzed by two techniques - Compton
Subtraction and weighted least squares computer program.
COMPTON SUBTRACTION
Spectra from several recounts were used with this method,
thus utilizing half-life determinations for the various gamma
peaks to confirm the analysis.
LEAST SQUARES PROGRAM
A computer program based on a weighted least squares
analysis was used. The weighting function was based on the
counting error in each channel. The number of isotopes
that can be used in the computer program is variable, but it
is limited to isotopes where standards are available.
Standards for the following isotopes were not available for
37
-------
the computer program: 91Sr, 92Sr, 92Y, 135I, 97ZrNb, and
143Ce. Gamma spectra taken about 2 weeks after the reactor
run were used for the analysis, The previously mentioned
isotopes would have decayed to one-thousandth or less of
their original activity by this time.
D. Correlation Coefficients
Linear correlation coefficients were calculated for both the
untransformed data and logarithmic transforms (transforms are
an attempt to make the data fit a straight line - the correlation
coefficient is a measure of the fit to a straight line). Particle
size and activity are distributed at each distance. Thus, a
point by point correlation, e.g. , parameter of particle versus
distance at which it was found is misleading. Thus, these cor-
relations are based on the mean of the parameter at each dis-
tance. The correlation for particle size and activity was done
on a point by point basis.
E. Elemental Chemical Composition
Chemical composition was determined by electron microprobe
(Norelco Instrument) analysis. In this process, the character-
istic X-rays from electron excitation are passed through an
X-ray energy dispersing crystal to a detector. Normally, an
emission angle from 30 to 70 degrees is measured with a
rotation of 2 degrees per minute. The signal and associated
angle are recorded on a strip chart recorder. Due to the large
number of particles to be analyzed, in most cases, just the
spectral peaks for the various elements were measured. The
particles were analyzed for U, Zr, Mo, Nb, C and O. The
area of the electron beam used on these samples was approxi-
mately one micron. The minimum detectable quantity of
38
-------
U, Zr, Mo and Nb was approximately 10~12 grams regardless
of beam size, providing that the beam remained entirely on the
particle. The minimum detectable limit is significantly greater
for elements of low atomic weight such as O and C.
The small beam size was used on all particles to ensure that
the beam remained on the particle being examined. Some
larger particles were also examined with a larger beam, approxi-
mating the particle size, to determine if detectable amounts of
the elements sought were spread over the entire surface.
The most conclusive semi-quantitative analysis of uranium and
carbon was accomplished by comparing the samples with a
crushed reactor bead mounted by the same procedure that was
used on the samples. The relative uranium-carbon count rate
ratios were used for comparison with the data from the sample.
The oxygen content was quantitated by comparing the uncorrected,
net count rate of the oxygen in the sample with the oxygen count
rate from ruby (Al_0 ). The usual mathematical corrections used
£• j
for quantitative probe analysis could not be used because mass
absorption coefficients and fluorescence corrections are not
available for carbon and oxygen.
F. Density of Particles
The density of eight particles (12 - 28|o. in size) was estimated by
use of Stokes1 Law and the settling velocity through hexane
(viscosity = 0. 326 cp). The equivalent diameter was taken to be
that of the two dimensional projection of a spherical particle of
equal cross sectional area. The determination of equivalent size
was done on a Zeiss Particle Size Analyzer. A measure of the
accuracy and reproducibility of this procedure was made by
using 27.4|jL silver spheres in the same experimental arrangement.
39
-------
Ten of these spheres were allowed to fall 15. 24 cm in hexane
and their terminal velocities were recorded. The average
settling velocity was 1. 28 cm/sec with a range of from 1.21-
1. 34 cm/sec. Based on the average measurement, a density
of 10.8 gm/cc was calculated for the silver spheres (pure
silver has a density of 10. 5). Inaccuracies caused by irregu-
larities of particle dimensions would tend to give a low rather
than a high density using the settling velocity technique.
G. Biological Clearing Rate of Internally Deposited Particles
for Rats
A preliminary biological experiment was performed with rats.
Particles with a CMDvof less than 10|j. were suspended in an
aqueous solution and injected in two rats; one by the intra-
tracheal route and the other intraesophageally. The main
objective of the study was to establish methodology, with
secondary objectives of obtaining gross indications of clearance
times and routes and particulate solubility in biological fluids.
Following the injection, each animal was placed in a restrainer
between the 9-inch opposed sodium iodide crystals and whole-
body counted. This procedure was repeated daily on each rat
until the detectable activity dropped to less than 50 percent of
the original body burden. At this point, the counting frequency
was changed to a weekly schedule and maintained at this rate
until significant counts were no longer obtained. In addition
urine and fecal eliminations were collected from each animal
and counted at the same counting frequency as that utilized for
the whole-body count.
*Count mean diameter.
40
-------
APPENDIX B
PARTICLE SURVEY RESULTS
Date of
Collec-
tion
February
1967
23
24
25
Distance
from Test
Cell "C"
in Miles
9
11
14
17
19
30
50
19
21.5
23
23. 5
24
25
26
26
29
34
65
66
69
72
Azimuth
from Test
Cell "C"
in True
Degrees
20
30
20
30
20
30
20
355
3
13
12
27
16
7
10
8
7
18
21
10
9
(41)
Number*
Parti-
cles
per
300 ft2
1 c »'* »'*
J, 3 -i- ~f
16**
16
16
0
4
0*ln »'- *'*
1* "I* ff
0
o * * *
l#*f ***
Number
Parti-
cles
per
100 m2
225****
0
15
0
3
0
0
54
57
57
57
14
5
12
12
6
4
-------
APPENDIX B
PARTICLE SURVEY RESULTS (continued)
Date of
Collec-
tion
February
1967
26
27 & 28
Distance
from Test
Cell "C"
in Miles
39
44
51
60
67
74
82
82
92
92
93
93.5
95
87
76.5
74
72
70
112.5
113
113.5
114
114.5
Azimuth
from Test
Cell "C"
in True
Degrees
5
4
5
7
4
0
356
356
6
7
9
10
11
7
8
8
9
10
3
2
1
0
359
Number* Number
Parti- Parti-
cles cles
per per
300ft2 100m2
4
7
6
4
5
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(42)
-------
APPENDIX B
PARTICLE SURVEY RESULTS (continued)
Date of
Collec-
tion
February
1967
27 & 28
(cont'd)
Distance
from Test
Cell "C"
in Miles
115. 5
115.5
93.5
93. 5
93. 5
94
94
95
91
Azimuth
from Test
Cell "C"
in True
Degrees
358
357
356
357
359
0
1
2
5
Number* Number
Parti- Parti-
cles cles
per per
300ft2 100m2
0
0
0
0
0
0
0
0
0
#The area surveyed was 300 ft for indicated results in this column
and 100 m2 for other results. Results were then normalized to
100 m2 and included in the next column.
**P + Y contact readings for E-500 B GM survey instrument at time
of collection.
Particles at 19 miles 1 particle > 200 mR/hr
2 particles 100 - 200 mR/hr
3 particles 50 - 100 mR/hr
9 particles < 50 mR/hr
Particles at 21.5 miles 4 particles > 100 - 200 mR/hr
1 particle 50 - 100 mR/hr
11 particles < 50 mR/hr
Particle at 72 miles 1 particle 10-50 mR/hr
***Area surveyed was approximate.
#*##An area of about 35m2 was surveyed and 78 particles detected
and picked up.
43
-------
APPENDIX C
FREQUENCY OF PARTICLE SIZE
Size (|j. )
2
3
4
5
6
7
8
9
10
13
15
16
17
18
19
20
21
23
25
26
27
28
30
Frequency
3
7
6
12
9
3
5
5
6
3
2
6
2
5
1
2
4
2
1
1
1
2
1
% Frequency
2.8
6.4
5.5
11.0
8. 3
2.8
4.6
4.6
5.4
2.8
1.8
5.5
1.8
4.6
0.9
1.8
3.7
1.8
0.9
0.9
0.9
1.8
0.9
Cumulative %
< Stated Size
2.75
9. 18
14.7
25.6
34.0
36.7
41.3
45.9
51.3
54. 1
56.0
61.5
63.3
68.0
68.9
70.6
74.4
76. 1
77. 1
78.0
79.0
80.8
81.7
44
-------
APPENDIX C
FREQUENCY OF PARTICLE SIZE (continued)
Size (a )
32
33
40
45
46
47
48
50
51
52
58
60
78
81
83
115
144
Frequency
1
1
2
2
1
1
1
1
1
1
1
1
2
1
1
1
1
% Frequency
0.9
0.9
1.8
1.8
0.9
0.9
0.9
0.9
0.9
0.9
0.9
0.9
1.8
0.9
0.9
0.9
0.9
Cumulative %
< Stated Size
82.6
83.5
85.4
87.2
88. 1
89.0
90.0
90.8
91.9
92.6
93.6
94.5
96.4
97.3
97.2
99.1
100.0
45
-------
APPENDIX D
SURVEY METER READINGS OF PARTICLES
Distance
(Miles)
6**
7**
7
7
7
7
7
7
7
7
9
9
9
9
9
9
9
9
9
9
9
9
Size
(n)
40
6
19
13
40
32
7
26
30
18
23
7
33
20
3
9
3
60
7
45
5
83
P + Y
Activity*
(cpm)
NM
14,000
25,000
3, 100
600
3, 100
1,400
1,400
3,800
2,500
2,900
9,000
20,000
700
5,500
1,900
8, 500
14,000
3, 200
10,000
2,700
24,000
Distance
(Miles)
9
9
9
9
9
9
9
9
9
9
9
9
22.5
25
26
26
26
26
26
26
26
26
Size
(Ji)
5
78
6
9
10
3
78
28
144
5
4
3
16
13
6
5
18
3
47
10
9
10
P + Y
Activity*
(cpm)
3,800
19,000
11,500
5,000
2,000
13,000
16,000
6,000
26, 000
30,000
1,400
2, 100
NM
NM
2,500
3,400
1,800
7, 000
9,500
4,800
2,900
2,200
46
-------
APPENDIX D
SURVEY METER READINGS OF PARTICLES (continued)
Distance
(Miles)
9
9
9
9
9
9
9
9
9
34
34
39
39
39
39
44
44
44
44
Size
(H)
2
81
16
16
52
2
5
4
58
3
5
3
5
6
48
9
45
10
6
P + V
Activity*
(cpm)
28, 000
21,000
8,000
5,500
8, 500
6,000
1, 100
7,500
2, 100
650
650
2,500
1, 100
3,700
4,400
350
2,800
430
4,600
Distance
(Miles)
26
29
29
29
29
34
34
34
34
44
51
51
51
60
67
67
74
82
Size
(n)
6
6
13
50
21
17
8
10
18
10
8
18
21
15
51
21
4
5
P + Y
Activity*
(cpm)
1,200
7.500
1, 350
10,000
7,000
6,500
1,800
1,500
1, 100
170
8,000
7,500
350
2, 100
350
3,000
4,500
4,700
NM - Not Measured
*As measured by an RM-3A GM monitor.
**The particles from 6 and 7 miles were not located by surveying a
defined area. They are not reported in Table 1 and Figure 1.
47
-------
APPENDIX E
PARTICLE SIZE, ACTIVITY AND DISTANCE CORRELATION COEFFICIENTS
Relationship
Linear
Exponential
oo Exponential
Power
Function
Activity (A)
Size (S)
A vs S
A vs log S
S vs log A
log S vs log A
Coefficient Size (S)**
(r) Distance (D)
(68 Data Points)
0.46 S vs D
0. 25* S vs log D
0. 34 log S vs D
0. 17* log S vs log D
Coefficient
(r)
(6 Data Points)
-0.44*
-0. 66*
-0.41*
-0. 64*
Activity
(A)**
Distance
(D)
A vs D
A vs log D
log A vs D
log A vs
log D
Coefficient
(6 Data Points)
-0.64*
-0. 69*
-0.65*
-0.71*
^Correlation coefficient not significantly different from zero at the 95% confidence level.
**Correlation performed on the average size or activity for a distance interval, rather than each particle.
-------
APPENDIX F
ISOTOPIC FRACTIONATION
Relative abundances of 235U fission products at one hour after fission
relative to "Mo, were obtained from Bolles and Ballou. The ratios of
fission products identified for each sample were then related to the
amount of 99Mo found. These ratios, based on data from Table 4 in the
report are presented in Table F-l. Each ratio calculated for each
sample was divided by the corresponding ratio calculated from Bolles
and Ballou to determine an "enrichment factor" for the isotope relative
to the amount expected on the basis of 99Mo. These enrichment factors
are presented in Table F-2.
From Table F-2 it can be seen that the zirconiums, 103Ru, 140Ba, 141Ce,
and 147Nd are enriched relative to 99Mo, while 132Te and 143Ce are
depleted. This might also be interpreted to mean that 99Mo is depleted
relative to most of the other isotopes quantitated. It is also observed
that the enrichment factors for 95Zr and 97Zr are generally the same
within each sample, although they may vary between samples. In
general, the enrichment factors for the ceriums differ by about an
order of magnitude within each sample. The activity values are
plotted in Figures F-l and F-2 for the ceriums and zirconiums.
Linear correlation coefficients were determined to be 0. 54 for the
141Ce/143Ce ratios and 0.97 for the 95Zr/97Zr ratios. Similar cor-
relations may be determined for any other pair of isotopes.
49
-------
Table F-l. Ratios * of fission product activities based on "Mo
Isotope
'5Zr
"Zr
"Mo
"»Ru
132Te
140 Ba
141Ce
UJCe
147 Nd
Bolles &
Ballou**
0.
4.
1.
0.
0.
0.
0.
1.
0.
046
05
00
041
58
23
093
92
12
20528
A B
ND
ND
1.00
ND
0.097
1.7
0.92
ND
ND
ND
ND
1. 00
ND
0.07
1.0
0.63
ND
ND
A
0.
21
1.
0.
0.
0.
0.
0.
21
00
ND
25
13
23
71
25
20540
B
0
1
0
0
0
12
0
1
.85
ND
.00
.31
.46
.87
.41
. 5
C
0.
16
1.
0.
0.
0.
0.
0.
21
00
ND
13
11
19
51
38
A
0.
55
1.
0.
1.
0.
2.
1.
20542
B
68
00
ND
68
3
88
0
0
0.
29-
1.
0.
0.
0.
0.
1.
0.
32
0
00
17
48
78
53
3
79
20543
0.
6.
1.
0.
0.
0.
0.
04
6
00
007
009
ND
001
009
ND
20544
0.
6.
1.
0.
0.
1.
0.
0.
1
2
00
ND
07
13
3
34
26
A
0.
74
1.
1.
0.
1.
1.
3.
1.
20545
B C
78
00
4
98
6
2
0
4
0.
84
1.
2.
0.
1.
1.
1.
0.
51
00
3
35
9
6
0
79
0.
5.
1.
0.
0.
0.
0.
0.
05
6
00
ND
02
23
08
23
09
D
0.
28
1.
0.
0.
0.
0.
1.
0.
31
00
75
21
82
71
2
77
20546
0.42
30
1.00
ND
0. 18
0.73
0. 11
1.2
0.70
''•'These ratios are based on calculated activities before being rounded off to two significant figures for Table 2.
**Values obtained from USNRDL-456. Ratio of isotope activity to "Mo activity at H+l hour.
50
-------
Table F-2. Isotopic fractionation factor based on "Mo
Isotope
"Zr
"Zr
"Mo
103Ru
132Te
u°Ba
ulCe
U3Ce
U7Nd
20528
A
1
0. 17
7.6
9.9
...
B
...
...
1
...
0. 12
4. 5
6.8
---
A
4.6
5. 1
1
...
0.43
0.56
2. 5
0. 37
2. 1
20540
B
19
...
1
7.6
0.79
3.8
130
0. 21
13
C
4.6
3.9
1
...
0.22
0.48
2.0
0.26
3.2
20542
A
15
14
1
...
1. 2
5.6
9. 5
1.0
8.3
B
7
7.2
1
4. 1
0.83
3.4
5.7
0.68
6.6
20543
0.87
1.6
1
0. 17
0.015
...
0.01
0.005
20544
2. 2
1. 5
1
...
0. 12
0.56
14
0. 18
2.2
A
17
18
1
34
1.7
7.0
13
1.6
12
20545
B
11
21
1
56
0.60
8.3
17
0.54
6.6
C
1. 1
1.4
1
--.
0. 034
1.0
0.86
0. 12
0.75
D
6.7
6.9
1
18
0. 36
3.6
7.6
0.62
6.4
20546
9. 1
7.4
1
...
0. 31
3. 2
1.2
0.62
5.8
51
-------
1O*
105
0)
U
r>
«
1O"
103
1
I I I I I I I
d
W
~ *®
W
I I II III
I I I I I I I I
« *
o
V
I I I I I I I I
I I
d
«-
^
I I
03 10« 1Q5
141Ce
Figure F-l. Ce versus Ce activity for selected Phoebus IB, EP-IV
particles.
-------
F- i i i l I i
1 1—I I I I 11
1O6
105
N
m
o-
104
103
105
1 1 I I I I I I I I I I I I I I
1O6
107
"Zr
Figure F-2. 95Zr versus 97Zr activity for selected Phoebus IB, EP-IV particles.
53
-------
DISTRIBUTION
1 - 15 SWRHL, Las Vegas, Nevada
16 Robert E. Miller, Manager, AEC/NVOO, Las Vegas, Nevada
17 Robert H. Thalgott, Test Manager, AEC/NVOO, Las Vegas, Nev.
18 Henry G. Vermillion, AEC/NVOO, Las Vegas, Nevada
19 D. W. Hendricks, AEC/NVOO, Las Vegas, Nevada
20 Robert R. Loux, AEC/NVOO, Las Vegas, Nevada
21 Central Mail & Records, AEC/NVOO, Las Vegas, Nevada
22 D. Hamil, AEC/NVOO Library, Las Vegas, Nevada
23 M. Klein, SNPO, Washington, D. C.
24 R. Decker, SNPO, Washington, D. C.
25 R. Hartfield, SNPO-C, Cleveland, Ohio
26 J. P. Jewett, SNPO-N, Jackass Flats, Nevada
27 - 30 R. Nelson, SNPO-N, NRDS, Jackass Flats, Nevada
31 William C. King, LRL, Mercury, Nevada
32 Roger Batzel, LRL, Livermore, California
33 H. L. Reynolds, LRL, Livermore, California
34 H. T. Knight, LASL, Jackass Flats, Nevada
35 P. Gothels, LASL, Los Alamos, New Mexico
36 Harry S. Jordan, LASL, Los Alamos, New Mexico
37 Charles I. Browne, LASL, Los Alamos, New Mexico
38 William E. Ogle, LASL, Los Alamos, New Mexico
39 F. L. Di Lorenzo, NTO, NRDS, Jackass Flats, Nevada
40 H. G. Simens, NTO, Aero-jet General Corp. , Jackass Flats, Nev.
41 R. A. Smith, NTO, NRDS, Jackass Flats, Nevada
42 G. Grandy, WANL, NRDS, Jackass Flats, Nevada
43 E. Hemmerle, WANL, Pittsburgh, Pennsylvania
-------
44 M. I. Goldman, NUS, Washington, D. C.
45 J. Mohrbacher, Pan American World Airways, Jackass Flats, Nev.
46 P. Allen, ARL/ESSA, AEC/NVOO, Las Vegas, Nevada
47 Martin B. Biles, DOS, USAEC, Washington, D. C.
48 H. Booth, ARL/ESSA, AEC/NVOO, Las Vegas, Nevada
49 C. Anderson, EG&G, Las Vegas, Nevada
50 R. S. Davidson, Battelle Memorial Institute, Columbus, Ohio
51 Byron Murphey, Sandia Corp. , Albuquerque, New Mexico
52 Maj. Gen. Edward B. Ciller, DMAS USAEC, Washington, D. C.
53 Chief, NOB, DASA, AEC/NVOO, Las V^egas, Nevada
54 - 55 Charles L. Weaver, PHS, BRH, Rockville, Maryland
56 John C. Villforth, Director, BRH, Rockville, Maryland
57 Arden Bicker, REECo Rad. Safe. , Mercury, Nevada
58 Southeastern Radiological Health Lab. , Montgomery, Alabama
59 Northeastern Radiological Health Lab. , Winchester, Mass.
60 - 61 DTIES Oak Ridge, Tennessee
62 Wm. Link, BRH Library, Rockville, Maryland
63 John Bailey, Office of Information, BRH, Rockville, Maryland
64 - 65 Joseph Maher, International Atomic Energy Ass'n, Vienna, Austria
------- |