SWRHL-32r
FINAL REPORT OF OFF-SITE SURVEILLANCE
FOR THE
NRX-A5 TEST SERIES
by the
Southwestern Radiological Health Laboratory
Department of Health, Education, and Welfare
Public Health Service
National Center for Radiological Health
October 15, 1968
This surveillance performed under a Memorandum of
Understanding (No. SF 54 373)
for the
U. S. ATOMIC ENERGY COMMISSION
rr *fw"i|t"i *rtriij_ipi»ipii jj_iiimgOi''^."'rjj'~ ^^fi Z,
lm
£~^i ffijj
-------
LEGAL NOTICE
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, dissemin-
ates, or provides access to, any information pursuant to his employ-
ment or contract with the Commission, or his employment with such
contractor.
019
-------
SWRHL-32r
FINAL REPORT OF OFF-SITE SURVEILLANCE
FOR THE
NRX-A5 TEST SERIES
by the
Southwestern Radiological Health Laboratory
Department of Health, Education, and Welfare
Public Health Service
National Center for Radiological Health
October 15, 1968
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 provided off-site
radiological surveillance for the NRX-A5 Project Rover Reactor Test
Series at NRDS, Test Cell A. During the period in which this series
was conducted, there were four experimental plans (EP's) in the NRX-A5
series, two of which were full power runs (1100 Mw) of about 15 minutes
duration which produced detectable amounts of radioactivity off-site.
Radioactive effluent released by the EP-III on June 8, 1966, was de-
tected by ground level surveillance in the southwest off-site quadrant.
'Effluent released by the EP-IV on June 23 was detected by ground level
surveillance along an azimuth of about 30° (20° cloud width) to the Utah-
Nevada border, about 190 miles from the Test Cell. Although off-site
contamination occurred from the NRX-A5 test series, surveillance
indicated that radioactivity levels did not exceed the radiation protection
[ '
guides established by the Atomic Energy Commission (AEC Manual
Chapter 0524) for the off-site population (based on the Federal Radiation
Council Guidelines). The peak potential thyroid dose, for a child with
a 2 gram thyroid, in the off-site area, from this series was about
20 millirad.or less and the external whole body exposure about 1 mR
(at different locations).
-------
TABLE OF CONTENTS
ABSTRACT i
TABLE OF CONTENTS ii
LIST OF TABLES iv
LIST OF FIGURES v
INTRODUCTION 1
OPERATIONAL PROCEDURES 4
A. External Radiation Measurements 4
1. Ground Monitoring 4
.2. Exposure Rate Recorders 5
3. Aerial Cloud Tracking 5
4. Film Badges and TLD's 5
B. Radioactivity in Environmental Samples 7
1. Air Samples . 7
2. Milk Samples .10
3. Vegetation Samples 10
4. Water Samples 11
RESULTS 12
A. NRX-A5, EP-1 and II 12
B. NRX-A5, EP-III 12
1. Sampling Results , 12
a. Ground monitoring 12
b. Film badges and TLD's 15
c. Air samples 15
d. Milk samples 18
e. Vegetation samples 18
f. : Water samples 18
C. NRX-A5j EP-IV 19
1. Sampling Results , 22
a. Ground monitoring, 22
b. Film badges and TLD's 22
11
-------
Table of Contents (continued)
c. Air samples 22
d. Milk samples 25
e. Vegetation samples 29
f. Water samples 31
CONCLUSIONS 32
REFERENCES 38
APPENDICES 39
DISTRIBUTION
111
-------
LIST OF TABLES
Table 1. NRX-A5 experimental plans.
Table 2. Threshold detectability in picocuries(pCi) at
time of count of several radionuclides in air
samples (90% confidence level).
Table 3A. Meteorological data taken by ESSA, ARFRO,
for NRX-A5, EP-HI.
Table 3B. Supplementary winds aloft: June 8, 1966.
Table 4. NRX-A5, EP-III air sample results,
June 8, 1966.
Table 5. Vegetation results, NRX-A5, EP-III,
June 8, 1966.
Table 6. Meteorological data taken by ESSA, ARFRO,
for NRX-A5, EP-IV.
Table 7. External gamma exposures, NRX-A5, EP-IV
(above background).
Table 8. NRX-A5, EP-IV gross beta air sample results.
Table 9. NRX-A5, EP-IV air sarr^ple results.
Table 10. NRX-A5, EP-IV milk results.
Table 11. Radiation protection standards.
Table 12. Principal air concentrations resulting from
NRX-A5.
Table 13. Summary of results and doses from NRX-A5.
13
14
17
19
21
23
23
24
26
33
34
36
IV
-------
LIST OF FIGURES
Figure 1. Hotlines for NRX-A5, EP-III, June 8, 1966 and
EP-IV, June 23, 1966 (arrival times aloft). . 3
Figure 2. Location of air samplers and RM-11 exposure rate
recorders for NRX-A5, June 1966. 6
Figure 3. Milk and air sampling locations for NRX-A5,
EP-III, June 8, 1966. 16
Figure 4. Milk and air sampling locations for NRX-A5,
EP-IV, June 23, 1966. 20
Figure 5. Milk concentration vs. time after release at
the Kirkeby Ranch, three miles north of
Shoshone, Calif. , NRX-A5, EP-IV,
June 23, 1966. 28
Figure 6. Results of vegetation samples taken on >
Highway 25 following NRX-A5, EP-IV,
June 23, 1966. 30
v
-------
INTRODUCTION
This report presents the results of the off-site radiological surveillance
program conducted by the .Public Health Service (PHS) for the NRX-A5
Reactor Test Series (Experimental Plans I, II, III and IV) at the Nuclear
Rocket Development Station (NRDS).
Under a memorandum of understanding with the Atomic Energy Com-
mission (AEC), the U. S. Public Health Service conducts a program
of radiological monitoring and environmental sampling in the off-site
area surrounding the Nevada Test Site (NTS) and the Nellis Air Force
Range (NAFR) which include the NRDS and Tonopah Test Range. For
simplicity, this combined area will, be termed the test range complex
in this report.
The NRX-A5 was the fourth fueled reactor in the NRX series of the
Rover Program. The reactor was placed so that the hydrogen coolant
and escaping fission products were exhausted upwards. The primary
objective of the program was to obtain accumulated operating time at
design conditions. The series was conducted at Test Cell A under the
auspices of the Rover Nuclear Engine for Rocket Vehicle Application
(NERVA) program, which is directed by the Space Nuclear Propulsion
Office (SNPO).
The reactor was operated at full power for an accumulated time of about
30 minutes;, resulting in an integral power of about 2. 1 x 106Mw-sec.
The peak power was 1200 Mw. The experimental plans are outlined
in Table 1.
The effluent from both EP-III and EP-IV was detected in off-site environ-
mental samples. The general hotlines and boundary of the area where
1
-------
fresh fission products or radioactivity above background was found at
ground level are indicated in Figure 1. The EP-III effluent was spread
over a relatively large arc because of considerable wind shear and
shifting winds during and after the test. The effluent to the north-
east of NEDS for EP-III was due to the northeasterly flow of surface
level winds at test time which resulted in a small segment of the cloud
going towards Control Point 1. The broken line on Figure 1 indicates
the boundary where the effluent from EP-III was observed; the arrow
indicates the main cloud trajectory.
Table 1. NRX-A5 experimental plans.
Experi-
mental
Plan
EP-I
EP-II
Date .,
1966
.May 2,6
June 8
Time of Opera-
tion, PDT
AM
Integral Power i
Mw -sees
! f,
,; Criticality and |
drum calibration
Low power test
Radioactivity
Detected
Off -Site
No
No
EP-III June 8 1402-1418
'EP-IV June 2'3 1035-1050
1.1 x 106
(Full Power)
1. 0 x 106
(Full Power)
Yes
Yes
-------
QUEEN CITY,
LSUMMLT_/?a>
,!
DANSBY RN.»
FURNACE
REEK 2?
190
DEATH VALLEY OCT.
SCALE IN MILES
5^P^--^
OB 10 16 20 29
Figure 1. Hotlines for NRX-A5 EP-III, June 8, 1966, and EP-IV, June 23, 1966.
(Cloud arrival times for EP-IV are based on aircraft tracking).
3
-------
OPERATIONAL PROCEDURES
The Off-Site surveillance program was comprised of routine monitoring
stations (includes air, milk and water) and mobile monitoring teams.
The monitoring teams were initially positioned on the basis of the hot-
line prediction by the Environmental Science Services Agency, Air
Resources Field Research Office (ESSA, ARFRO) with final positioning
and sampling based on the airplane surveillance results and the moni-
tors' results.
A. External Radiation Measurements
1. Ground Monitoring
Ground monitors tracked the reactor effluent passage and deter-
mined exposure rates at several locations with portable instruments.
Each monitor was equipped with an Eberline E-500B, a Precision
Model 111 Standard "Scintillator11', and a Victoreen (Radector Model
No. AGB-5dB-SR. ' ' :
The Eberline E-500B is a Geiger Mueller instrument with a range
i
of 0 to 200 milliroentgens per hour (mR/hr) beta and/or gamma
oh four scales with an external halogen filled GM tube and a 0 to
2000 mR/hr, gamma only, range from an internal Anton 302 6M
tube.
The Precision Model 111 Standard "Scintillator" is used primarily
for low-level detection and an indication of cloud passage. It has
a range of 0 to 5 mR/hr on six linear scales.
The Radector has a range of 0. 05 to 50, 000 mR/hr on two loga-
r i
rithmic scales. This instrument employs an inert gas ionization
chamber.
-------
The above instruments are calibrated with l 37Gs and are generally
accurate to about 4^20% for this energy. Exposure rate readings can
be made to two significant digits.
2. Exposure Rate Recorders
Eberline RM-11 exposure rate recorders are placed at twenty-one
stations around the test range complex (Figure 2) and are opera-
tional on a routine basis. These recorders utilize a Geiger Mueller
tube detector to document radiation levels at specific locations.
The instrument has a 0. 01 to 100 mR/hr range on a 4 cycle log
scale. The gamma exposure rate is recorded on a 30-hour strip chart.
The RM-11 is accurate to 4_20% as calibrated with a 1 37Cs source.
3. Aerial Cloud Tracking ><
An Air Force U3-A aircraft, matined by two Public'Health Service
monitors equipped with portable'monitoring instruments identical
to those of the ground monitors (also a Radector ion chamber with
a range of Ot,to 1000 R/hr), tracked the reactor effluent to assist
the positioning of ground monitors and to determine,the general
magnitude o;f the release. Public Health Service cloud sampling
aircraft were also used as aids in cloud tracking, hpwever their
primary purpose was cloud sampling in order to determine cloud
size and inventory. The results of their sampling are reported
separately by the SWRHL Engineering Development Program. Long
range tracking of the effluent cloud is also done by the NATS and
ARMS aircraft from EG&G who also write a separate report.
4. Film Badges and TLD's
The PHS routinely maintains approximately 56 film badge stations
(5 badges toi a station) off the teat range complex and assigns badges
to approximately 120 off-site residents. DuPont type 555 film is
-------
OROVADA
PARADISE
DEETH 0/WELLS
BATTLE MTN
N E \V A D A
DUCKWATER
PINE CR RN
OUNDMTN
WARM
SPRINGS
- NELLIS AIR i
SCOTTY'S
JUNCTION
LATHRO
WELLS
INDIAN SPRINGS
PAHRUMP
D- AIR SAMPLER WITH PREFILTER
_ AIR SAMPLER WITH PREFILTER
"~ AND CHARCOAL CARTRIDGE
~- RM-II DOSE RATE RECORDER
Figure 2. Location of air samplers and RM-11 dose rate recorders for
NRX-A5. June 1966.
-------
used in the badge. The results of exposures are accurate to +50%
in the 20 to 100 mR range and +10% in the 100 to 2000 mR range.
The lower limit of detectability is 20 mR. These sensitivities
assume no heat damage, which produces interference at some
locations.
As part of the external dosimetry program the PHS also has 21
stations where thermoluminescent dosimeters (TLD) are located
in conjunction with the film badge stations. Three EG&G Model
Tl-12 CaF TLD's are located at each station. These dosimeters
have a sensitivity of 5 mR above background with an accuracy of
+ 10% and standard deviation at the 90% confidence level of 2.8%.
They have an upper exposure limit of 5, 000 R.
B. Radioactivity in Environmental Samples
!
1. Air Samples
During June, one-hundred and eight air samplers were routinely
operated in the western United States, thirty-eight of which were
located in Nevada (Figure 2). Supplementary temporary air sam-
pler locations were established as deemed necessary to cover
cloud passage. The routine samplers were the Gelman Tempest
type and were equipped with Whatman 4 inch 541 prefilters. A
portion of the routine samplers and all supplementary stations
were equipped with MSA char coil cartridges.
The Tempest air sampler used by SWRHL employs a Cast vacuum
pump driven by a 1/2 or 3/4 horsepower motor. The pump runs
at about 140,0 rpm with an average flow rate of about 10 cfm.
The supplementary temporary air samplers consisted of a Cast
Model No. 0(740 positive displacement pressure-vacuum pump
coupled to a';Rockwell Model No.. 415 gas meter for precise mea-
surement of,air flow. The flow rate of these systems averages
about 6 cfm.
7
-------
All air sample prefilters and charcoal cartridges collected follow-
ing the NRX-EST series were returned to the Southwestern Radio-
logical Health Laboratory in Las Vegas for analysis. Prefilters
were counted simultaneously for gross beta and alpha activity with
a Beckman "Wide Beta" 4-inch low background (6 cpm beta) pro- .
portional counting system. This system has an efficiency of approx-
imately 45% for 0. 54 MeV betas. Gross beta concentrations were
computed at the time of count for the purpose of screening samples
and delineating the effluent trajectory. Samples which were be-
lieved to contain fresh fission products were recounted several
times. Based on these counts, an individual decay constant was
computed for each sample. This constant was used to extrapolate
i ; . ,' : 1
the gross beta result to the end of the collection period.
i p
All prefilters were analyzed for,the predominant biologically
significant gamma emitting isotopes by using a 4" bjy 4" sodium
iodide crystal and multi-channel analyzer. Reported values are
corrected for radioactive decay,fo the end of the collection period.
f
Since it was not possible to define duration of effluent passage at
all locations, the reported values given as pCi/m3 assume an
average concentration over each,entire sampling period. Results
are also reported in ? p . This unit is obtained by
m.i i /
multiplying pCi/m3 by the sampling time in seconds (or hours)
and results in the total cloud pas.sage exposure. ;
, i . i
All charcoal cartridges were analyzed for gamma isotopes using
a 4"x 4" sodium iodide crystal coupled to a multi-channel pulse
height analyser set to view energies from 0 to 2 MeV. The activity
on the cartridge should represent primarily the gaseous radio-
i
iodines. ., ;
-------
The analyses of the gamma spectra were performed by an IBM 1620,
utilizing a matrix technique. This method compensates for the
interference between isotopes for a given spectrum by the simul-
taneous solution of n equations containing n unknowns, where n
represents the number of isotopes for which solution is sought.
Due to time and memory limitations on the 1620, the matrix is
limited to eight (n=8) isotopes. The input to the computer program
is variable so that a determination may be made for any eight
isotopes for which standard spectra are available.
The threshold detectability for several radionuclides in air samples
is presented in Table 2. These yalues are based on an examina-
tion of previous data collected under the following conditions and
assumptions:
a. Count time in days afte^ fissioning as indicated by footnotes.
b. Prefilters collect unfractionated fission products resulting
in a complex spectrum.,.,
c. Only the gaseous fission products (primarily iodines) are
collected on the MSA charcoal cartridge. .,
d. An eight isotope matrix is employed for computation and
isotopes other than those examined are present in amounts
which are small relative to those eight.
e. Natural activity on air samples is approximately five times
system background.
i'
Table 2. Threshold detectability in picocuries (pCi)* at time cf count of
several radionuclides in air samples (90% confidence level).
Sample Type
Whatman No. 541
MSA Charcoal
'131I
500
200
200
100
132Te-I
1000
-
400
-
1B3]-
500
200
2Q'0
100
135J
1000 '
-
400
-
140Ba-La
500
200'1
200'
100
Length
of Count
10 min.
10 min.
10 min.
10 min.
Notes
1
2
1
2
1 - counted at less than 3 days after fissioning.
2 - counted at 3 days or more after fissioning.
*1 pCi = 10"12 curie. ,
9
-------
2. Milk Samples
After the release of radioactivity from NRDS, milk samples were
collected from dairy farms and farms producing milk for their
own consumption, which were believed to have been in the'cloud
path. All liquid samples are counted, with no prior preparation,
in 3. 5 liter inverted well aluminum beakers which are placed over
a 4Mx 4" sodium iodide crystal. Each milk sample is counted for
40 minutes using a multi-channel analyzer viewing an energy range
from 0 to 2 MeV. The lower lirq.it of detection for 131I and 133I
in milk is about 20 pCi/1 at time of count (if l 3 7Cs <100 pCi/1),
and all results below that value ^,re reported as non-detectable.
The reported values have, at tirr,|e of count, a 2 sigma error estimate
of +15 pCi/l;or +10%, whichever is greater.
Biological discrimination limitsff;he number of radiqnuclides present
in a milk sample. The time delay between ingestion by the cow,
production of milk, and its analysis also removes short half-life
isotopes such as l 32 I and 1 3 5I. . ,
3. Vegetation Samples
Vegetation samples were collected in the suspected1 effluent tra-
jectory to indicate deposition oh'^he ground and thus the general
cloud trajectory. They were als,p obtained at most milk sampling
locations, with an effort made to make the sample representative
of the cows' feed. These samples were taken as ea'rly indicators
of where milk might be contaminated and the general level of con-
tamination. ,, ..
The limit of idetectability for specific isotopes in vegetation sam-
ples is several hundred picocuries per kilogram and' is dependent
on the interference from other is,otopes and sample size.
10
-------
4. Water Samples
Water samples are routinely collected from about 30 locations
around the test range complex. In addition special samples may
be taken in the area of suspected effluent passage. The sensitivity
for detection of radioiodine in water is about the same as that for
milk if significant quantities of other gamma emitters are not
present.
11
-------
RESULTS
A. NRX-A5, EP-I and II
Experimental Plan I (EP-I) was the criticality and drum calibration
test and EP-II was a low power test. There was not a significant re-
lease of radioactivity and radioactive effluent was not detected off-site.
The PHS had people on standby for both ground and aerial monitoring
for both tests.
B. NRX-A5, EP-III
Experimental Plan III was the first full power run on the NRX- A5
reactor. As a result of the aerial cloud tracking results, ground
monitoring was performed in the southwest quadrant off-site. PHS
aerial monitoring results indicated that the effluent cloud was split
into two sections at about 8, 000 and 9, 000 feet MSL by the large wind
shear which existed at test time (meteorological data fr'om ESSA, ARFRO
in Table 3). The low altitude section of the cloud went towards CP-1
at a bearing of about 40°. The main cloud went in a westerly direction
with an initial be'aring of about 270 i'or about 25 miles and later in a
more southerly direction. The peak exposure reading in the airplane
was 7 mR/hr at about 8 miles from the reactor, with the highest off-
site reading being 3 mR/hr at the south boundary of NRDS. The ground
.r,
sampling locations for air and milk are shown in Figure 3.
1. Sampling Results
a. Gr,ound Monitoring M
Qround monitors were located on U.S. 95 at the time and loca-
tion of :cloud passage. The|monitors did not detect gamma
exposure rates above background. The RM-ll;recorders did
not indicate any exposure rates above background.
12 '
-------
Table 3A. Meteorological data taken by ESSA, ARFRO, for NRX-A5,
EP-III.
Sky Condition: 5000' Sctd. , Est. 18, 000' Overcast
Clouds: 4/10 Cumulus, 6/10 Altocumulus
Visibility: Unrestricted
Upper Air Data At: Jackass Flats, Nevada, 1400 PDT, 6/8/66
Height Wind
(Ft.MSL) (Deg/Kts)
SFC 3615
4000
4068
4816
5000
6000
6201
6955
7000
8000
9000
10000
10151
11000
11680 .
12000
13000
14000
14534
.15000
15026
15420
16000
17000
18000
18806
210/10
220/11
' 210/11
' 210/07
210/07
180/04
190/03
200/01
210/01
120/02
10d/04
080/09
090'/ 08
M .,
M ,,
14Q/04
130/03
060/03
060/04
080/04
100/05
110/06
120/08
130/15
13Q/20
M ,
Pressure
(mb)
887
876
871
850
841
814
807
785
784
757
730
703
700
677
660
652
627 .
604
593
583
582
572
558
536
516
500
_ . Dew Relative
Temperature _. .
o Point Humidity
. ( U) (°c) (%)
24.9
22. 3
21.5
19.3
18.8
15.4
' 14.6
13.4
13.4
1 10.8
" 8.0
5.2
^ 4.9
- 2.6
-: 0. 5
-0. 1
. -2.9
.5.2
-6.4
-6.9
-6.9
-7.2
-8.6
i-10.9
-13.0
-14.9
1. 1
1.9
2. 2
1. 3
0.9
-1. 3
-1. 0
-1. 5
-1. 5
-2.6
-4. 1
-5. 5
-5.8
-7 . 0-
-8. 5
-8.9
-11.0.
-13. 0
-13.6
-16.9
-16.9
-17.4
-18. 5
-20. 2
-21.7
-23.4
21
26
28
30
30
32
34
36
36
39
42
46
46
49
51
52
53
54
56
47
47
44
45
46
47
48
SFC = Surface
M = Missing
13
-------
Table 3B. Supplementary winds aloft: June 8, 1966.
Data (Degrees/Knots)
Observational Point :
Time of Ob. (PDT) :
Type of Measurement :
H Surface
E
I
G
H
T
(Ft. MSL)
Time of
Type of
H
E
I
G
H
T
(Ft. MSL)
4000
5000
6000
7000
8000
9000
10000
11000.
12000
13000
14000
15000
Ob. (PDT) :
Measurement :
Surface
4000
5000
6000
7000
8000
9000
10000
11000
12000
13000 ;
14000
15000
Jackass Flats,
1030 1100
Radar Radar
170/04 290/02
170/02
HO/
090/
080/
080/
100/
no/
120 /
130 /
150/
160/
ISO/
131
01
05
10
1.4
10
07
12
11
11
08
11
5
Radar
220/
230/
220/
ISO/
130/
120/
06
09
07
07
07
06
110/05
100/
10
-
-
-
-
-
290/01
280/
200/
120 /
lOQ/
080/
09 O/
110/
130/
150/
170/
ISO/
01
03
06
11
13
12
13
10
13
10
11
1330
Radar
230/
240/
220/
190/
ISO/
170/
090/
10
08
11
10
07
04
06
090/08
-
_
-
-
Nevada,
1130
Radar
190/06
200/
160/
01
02
090/04
07 O/
070/
080/
080/
090/
ipo/
150/
1.70/
^i70/
06
09
11
13
14
14
10
13
15
1345
Radar
240/
230/
24 O/
240/
210 /
ISO/
080/
080/
_ .
i
'r ~ ~
05
05
10
07
03
03
07
08
-
_
-
-
-
Elevation 3615'
1200 1230
Radar Radar
260/05 240/08
250/05
220/09
200/04
130/04
070/03
080/05
090/09
100/12
100/12
140/08
170/07
150/08
1400
Radar
210/10
220/11
210/07
180/04
210/01
120/02
100/04
080/09
M
140/04
130/03
060/03
080/04
230/06
190/02
100/03
100/06
100/09
100/09
100/13
100/12
120/08
160/06
180/05
1415
Radar
250/07
250/09
250/12
230/10
210/05
220/02
080/07
080/11
- - - - .
/
----
1245
Radar
240/05
260/04
250/07
200/06
150/08
120/05
100/11
090/12
1430
Radar
240/06
220/06
230/06
220/10
220/11
210/03
080/05
060/08
1300
Radar
210/07
230/07
220/05
170/04
160/06
130/08
110/06
090/09
.
1500
Radar
230/08
230/10
220/09
230/06
240/05
130/02
090/07
080/07
080/03
080/02
080/02
090/04
110/06
M - missing
14
-------
b. Film Badges and TLD's
The film badge and TLD results gave no indication of expo-
sures above background due to the reactor effluent.
c. Air Samples
Fresh fission products were detected on air samples as shown
in Figure 3 with the results given in Table 4. Gross beta
results which were above background are included, if they
coincide with the date" and area of effluent cloud passage, even
if fresh fission products weren't detected on the sample. These
high gross beta results are due to several causes:
(1) Reactor effluent - even those samples with fresh fission
productjs were near the limit pf detectability.' Thus, the sam-
ples marked NFFP may have contained fresh fission products,
but belqw levels of detection.
(?) Fallout from a non-U. S. test of May 9, 1966. It was
c
detected in environmental samples in the vicinity of the site
around June 7 and 8.
(3) High natural background levels due to normal fallout and
dust, etc. The general background level during June 1966 was
about 0. 5 pCi/m3 and occasionally values of about 1 pCi/m3
occurred.
The positive results found to the south and south-southeast of
the site are possibly due to the release of fission products
during 900! down of the reac.tor and to the northerly flow of sur-
face drainage winds at night. They also could have resulted
from the. large wind shear and changing wind direction after
i'
testing.;] The potential inhalation exposure from-radioiodines
1 : .
at the sampled locations is estimated to be less than 1 millirad
to an adult, assuming a breathing rate of 2. 3 x 10~4 m3/sec
15
-------
Round Mountain
5
L. NELLIS""
. r .- ~m. ^-i a i^^r i i / "» * rWKvrt
Bishop
Scotty's Jc^' r
Big Pine
Springdale£^? ' N.T.S,
CALIFORNIA
Silverlake
Boktr
Fresh fission products detected on air
samplers
Gross beta air samples above back-
ground
Fresh fission products not defected on
air samplers
MILES
26 00 76
Milk sampling and feed sampling
locations
Figure 3. Milk and air sampling locations for NRX-A5, EP-III, June 8, 1966.
16
-------
Table 4. NRX-A5, EP-III air sample results, June 8, 1966.*
Location
Beatty, Nevada
Death Valley Jet., Calif.
Death Valley Jet. , Calif.
Furnace Creek, Calif.
Furnace Creek, Calif.
Furnace Creek, Calif.
Lathrop Wells, Nevada
Pahrump, Nevada
Pahrump, Nevada
Pahrump, Nevada
Shoshone, Calif.
Barstow, Calif.
Ridgecrest, Calif.
Ridgecrest, Calif.
lOmi.S. of Beatty.Nev.
(Hwy. 95)
Springdale, Nev. (Hwy. 95)
Sampling Period
Start Stop
Day Hr Day Hr
08 0742
08 0645
09 0645
08 1130
09 1030
10 1125
08 0755
07 1200
08 1200
09 1200
09 1435
09 0700
08 1308
09 1425
08 1545
08 1540
09 0826
09 0645
10 0645
09 1020
10 1125
11 1155
09 0620
08 1200
09 1200
10 1200
10 1843
10 0700
09 1422
10 1315
09 0930
09 1156
Total
Time
(Hr)
24.
24.
23.
22.
25.
24.
22.
24.
24.
24.
28.
24.
25.
22.
17.
20.
6
0
9
8
0
6
3
0
0
0
2
0
3
9
3
3
Sample
Volume
(m3)
467
485
495
472
518
497
450
435
448
435
468
460
485
415
193
410
Col-
lector
P
C
P
C
P
P
C
P
P
P
C
P
P
P
P
P
P
P
P
C
P
C
Beta
Activity
(PCi/m3)
1. 1
1. 1
1. 1
1'. 8
1.0
1.5
1. 1
1.3
1.7
1.3
1. 1
1. 1
2.3
2. 1
1.9
0.7
Beta 131].
Exposure Notes
(pCi-hr/m3) pCi/m3 pCi-sec/m3
28
26
26
40
25
36
24
31
40
31
31
27
59
48
33
14
ND
ND
ND
ND
NFFP
0.7 5.7xl04
ND
NFFP
NGS
0.5 4.3x10*
1.7 1.4xl05
NGS
ND
NFFP
NFFP
NGS
NGS
NGS
0.7 4.4xl04
1.0 6.2xl04
ND
ND
133I
pCi/m3 pCi-sec/m3
<0. 1
<0. 1
1.4
5.2
0.8
ND
1.8
8.0
1. 1
1.8
2.4
0.4
ND
1. 2xl05
4. 3xl05
6.7x10"
1.4xl05
6.4xl05
9. 5xl04
1. IxlO5
1.5xl05
3. OxlO4
*Results extrapolated to end of collection.
Notes: NFFP - No fresh fission products detected.
P = Prefilter C = Charcoal cartridge
NGS - Not gamma scanned.
ND - Not detected.
-------
(20 m3/day), and using the values for the ICRP standard man' '
and assuming equal uptake of iodine associated with both vapor
and particles (see Appendix A for calculations).
d. Milk Samples
Milk and feed samples were obtained from the locations indi-
cated in Figure 3. The only milk samples with a detectable
level of radioiodine were from Dansby's Ranch, southwest of
Lathrop Wells, which had 40 pCi/1 of * 31I on June 13 and
50 pCi/1 of l 31I on June 17. Two samples prior to this (June 9
and 10) did not have detectable levels of radioiodine, although
vegetation from the pasture did show the presence of radio-
iodine (Table 5). Peak levels do not usually occur in milk
until 2 to 6 days after deposition on the pasture. There are
two potential sources of the 1 31I: fallout from ,a non-U. S.
nuclear detonation.of May 9, 1966, which was observed in air
samples about this time and/or the reactor effluent.
e. Vegetation Samples > i
Vegetation samples were taken at five mile intervals on U.S. 95
between; Springdale and Lathrop Wells, Nevada .on June 9. No
fresh fi'ssion products were detected in these samples except
for, those collected 10 miles] south of Springdalei and 5 miles
south of Beatty (see Table 5). Vegetation samples were also
taken at'Peacock Ranch nearj Springdale and at Dansby's Ranch.
The results for samples containing fresh fission products are
given ii> Table 5.
f. Water Samples
Fresh fi'ssion products were not detected in water samples
collected from Dansby's Ranch and near Springdale, Nevada.
18
-------
Table 5. Vegetation results, NRX-A5, EP-III, June 8, 1966.*
Location
10 miles south of Springdale
5 miles south of Beatty
Dansby Ranch, near Lathrop Wells
Dansby Ranch; near Lathrop Wells
Dansby Ranch, near Lathrop Wells
Dansby Ranch, near Lathrop Wells
Date
6/09/66
6/09/66
6/09/66
6/10/66
6/13/66
6/17/66
131J
pCi/kg
ND
ND
ND
230
560
420
133I
pCi/kg
600
1500
800
600
ND
ND
^Results extrapolated to end of collection time.
C. NRX-A5, EP-IV
The EP-IV was the second and final full power run on the NRX-A5
reactor. The EP-V which had been tentatively scheduled was canceled.
\
Ground monitoring and environmental surveillance was performed in
>.
the northeast quadrant of the off-site area based on aerial monitoring
results and initial ground monitoring. A reading of about 2 mR/hr in
n
the airplane near Coyote Summit (60 miles from the reactor) was
detected. An initial hotline of about £5 changing to about 30 beyond
60 miles was indicated. The effluent was tracked to the area around
Rapid City, South Dakota. Cloud effluent levels had decreased to the
point where further tracking could not be accomplished and the aircraft
returned to Las Vegas. The transport speed for distances greater
than 60 miles was about 26 mph. Fresh fission products were detected
in off-site samples of air, vegetation, and m-'lk; gamma exposure rates
were recorded by portable survey meters and the RM-ll recorders.
The air and milk sampling locations are indicated in Figure 4. Meteor-
ological data for the time of reactor run, taken by ESSA, ARFRO, is
given in Table 6.
19
-------
-xYelland Rn.
Rogers Ra'Af
Sacramento
Pass
Baker
Cummings R
GonGdaerrr18o
KirkebyR
Geyser Rn.w
Geyser Maint. St.
Blue Eagle Rn.
Springs
25 **Nyala
Warm Springs^:
Queen City Summit
i A Coyote Summit
Goss Rn.W )V
NEVADA
TEST
SITE
NELLIS
AIR FORCE
RANGE
Positive air samples
Positive milk samples
Negative air samples
Negative milk samples
Air samples with gross
beta above background
o Death Valley'Jet
Figure 4. Milk and air sampling locations for NRX-A5, EP-IV, June 23, 1966.
20
-------
Table 6. Meteorological data taken by ESSA, ARFRO, for NRX-A5,
EP-IV.
SFC
Sky Condition: Clear
Clouds: None
Visibility: Unrestricted
UPPER AIR DATA AT: Jackass Flats, Nevada 1035 PDT, 6/23/66.
Height
(Ft.MSL.)
3615
4000
4400
4728
5000
6000
7000
8000
9000
10000
10125
11000
12000
13000
13040
14000
15000
16000
17000
18000
18957
Wind
(Deg/Kts)
220/04
220/04
210/04
200/03
200/02
210/0'3
190/05
190/11
200/17
210/21
210/21
200/2:2
220/21
230/18
220/18
240/19
260/24
250/34
250/34
250/34
260/42
Pressure
(mb)
884
874
860
850
841 .
812
784
755
729
703
700
676
651
627
626
604
582
560
538
518
500
Temperature
(°C)
25.0
22.6
22.6
21.7
21.0
18.4
15.4
14/1
12. 1
9.9
9.4
7.2
4.. 6
2. 1
1.9
0.7
-0.7
-2.6
-4.4
-7. 0
-9.1
Dew Point
(°C)
-6.3
-2.9
-2.9
-3.7
-4. 2
-6.3
-8.8
-9.9
-11. 5
-13. 3
-13.8
-15. 5
-17.7
-19.8
-19.9
-21.6
-21.6
-24. 3
-25.2
-26.8
-28. 0
Rel. Humidity
(%)
12
18
18
18
18
18
18
18
18
18
18
18
18
18
18
17
17
17
18
19
20
21
-------
1. Sampling Results
a. Ground Monitoring
Monitors on Highway 25 between Queen City Summit and Coyote
Summit detected the cloud passage with portable survey instru-
ments. The highest off-site ground level external gamma
exposure* detected was at Goss1 Ranch (60 miles from the
reactor at an azimuth of 25G). Cloud passage was also indi-
cated by RM-11 recorders at Sunnyside and Lund, Nevada.
The results are given in Table 7.
Air monitoring results did not show fresh fission products at
Lund. Thus, it is assumed that the cloud did pass over Lund
(confirmed by aerial surveillance results), but .remained aloft.
b. Film Badges and TLD'sJ
<- h X
Film badge and TLD results gave no indication'of the reactor
effluent passage.
c. Air Samples
f r '':
Air samplers were operated at the locations indicated in
r,
Figure 4. In addition, air samples (including charcoal car-
tridges) were also taken throughout Utah. The positive air
sample results are given in Tables 8 and 9- The results from
Utah, except Garrison, indicated the absence of fresh fission
products. The gross beta results from Garrison and Geyser
Maintenance Station were above background, but specific
isotope'ianalysis is not available.
The potential inhalation exposure to an adult's thyroid, based
. i
on air sampling results and the method of calculation outlined
';For purposes of this report, exposure in mR -will be considered equiv-
alent to dose iri millirad. Also a dose in rads is assurhed to be equal
to rems (i.e. , !RBE of 1) for the doses in this report. r
22 ,
-------
Table 7. External gamma exposures, NRX-A5, EP-IV (above background),
Location
GOBS' Ranch
Coyote Summit
Sunny side
Lund
Distance
From
NRDS
60
60
130
150
Arrival
Time
(PDT)
1300
1300
1540
1600
Instrument
for
Measurement
E-500B
E-500B
RM-11
RM-11
Peak Expo-
sure Rate
mR/hr
l.Z
0. 1
0.02
above
bkgd.
Integrated*
Exposure
mR
1
0.06
0.05
<0.01
*This exposure is based on an integration of instrument readings over time
and is thus representing primarily cloud passage. Residual activity was
not noted and, therefore, is not included (the sensitivity of the instru-
ments was not sufficient to determine fallout at these low levels).
Table 8. NRX-A5, EP-IV gross betja air sample results.*
Sampling Period Total Sample Beta Beta
Location .Start Stop Time** Volume Activity Exposure Notes
Day Hr Day Hr (Hr) (m3) (pCi/;m3) (pCi-hr/m3)
Goss1 Ranch ;j
(NW of Coyote f
Summit) 231314 231500 o'l.S 17 14,4oO 26,000
Coyote Summit,
Hwy. 25
Sunny side, Nev.
Geyser Maint.
Station, Nev.
Garrison, Utah
.23
23
23
23
1135
0730
1602
0800
23
24
24
24
1540
0726
1610
0800
04.
23.
i
24.
22.
1
9
6
7
40
470
446
458
527
138
10. 1
3. 1
2, 160
3, 320
247
71
NGS
NGS
^Results extrapolated to end of collection time.
**Based on running time indicator .rather than time on and off.
NGS = Not gamma scanned. ;' ',-,
23
-------
Table 9. NRX-A5, EP-IV air sample results. ;
Location
Goss'
Ranch
Coyote
Summit
Sunny-
side
Col-
13 '-I
Time lector pCi/m 3
6/23 1314
6/23 1500
6/23 1135
6/23 1540
6/23 0730
6/24 0726
P
C
P
C
P
C
9. IxlO2
6.2xl02
ND
40
9.9
4.7
13Z
pCi-sec/m3 pCi/m3
5.8xl06
3.9xl06
ND
5.9xl05
8.6xl05
4. IxlO5
ND
1.2xl03
ND
50
ND
5. 1
I
133 !
UBj
pCi-sec/m3 pCi/m3 pCi-sec/m3
ND
7. 6xl06
ND
7.4xl05
ND
4.4xl05
1.6xl03
1. 7xl03
70
80
23
17
l.OxlO7
1. IxlO7
1. OxlO6
1.2xl06
2. OxlO6
1.5xl06
pCi/m3
1.6xl03
1. IxlO3
80
100
ND
4.8
pCi-sec/m3
l.OxlO7
7. OxlO6
1. 2xl06
l.SxlO6
ND
4. 2xl05
Potential adult
Inhalation
Dose(mrad)
5. 3
< 1
1
^Results extrapolated to end of collection time.
P - Prefilter. C - Charcoal cartridge. ND - Not detectable.
132 I is not reported on the prefilter because of interference from 97Zr.
-------
in Appendix A was about 5 millirad at Goss' Ranch, which was
near the hotline at a distance of 60 miles from the reactor.
An evaluation of this exposure on the basis of the new ICRP
4 '
model gives very similar results (assume 90% of vapor de-
posited in respiratory system and a mass median diameter
of 1 micron for the particulate radioactivity). A similar
analysis gives a thyroid inhalation dose of about 1 millirad
at Sunnyside, Nevada.
The air sampler at Goss1 Ranch was not started until after
cloud arrival. By estimating the total integrated air concen-
tration based on ground monitored results of exposure rates
versus time, the total potential adult thyroid inhalation dose
at GOSSH Ranch would be about 7 millirad. i
d. Mil'k Samples '
Milk and feed samples were obtained as indicated in Figure 4.
Samples were also obtained .'from the standby network in Utah.
A complete list of milk samples is given in App'endix B; The
results of milk samples containing fresh fission products are
given in Table 10. The samples from Utah did not have
detectable levels of fresh fission products. ,|
The maximum milk concentration found was at'the Kirkeby
Ranch, about 3 miles north 'of Shoshone, Nevada. The poten-
tial dose to a child's thyroid'(2 gram) was estimated from this
concentration to be 40 millirad based on the assumptions in
FRC-5 | (38 millirad from 1 31I and some contribution from
133I) which assumes an effective half-life of l 3|* I in milk of
about 5,'days. However, the' milk results from,-Kirkeby Ranch
did not if it the expected decay curve of an effective half-life
25
-------
Table 10. NRX-A5, EP-IV milk results.*
Location
3 mi. N. of Shoshone
(Kirkeby Ranch)
3 mi. N. . of Shoshone
(Kirkeby Ranch)
3 mi. N. of Shoshone.
(Kirkeby Ranch)
3 mi. N. of Shoshone
(Kirkeby Ranch)
3 mi. N. of Shoshone
(Kirkeby Ranch)
3 mi. N. of Shoshone
(Kirkeby Ranch).
3 mi. S. of Baker, Nev.
(Baker Ranch) ..
3 mi. S. of Baker', Nev.
(Baker Ranch) '
13 mi. N. of Shoshone
(Harbecke Ranch)
13 mi. N. of Shoshone
(Harbecke Ranch)
5 mi. S. of Baker'
(E. J. Cummings Ranch)
5 mi. S. of Baker1**
(E.J. Cumming's Ranch)
Nyala !'
I.
Date
6/24
6/25
6/26
6/27
6/30
7/01
6/30
7/01
6/26
6/27
6/26
6/27
6/24
Milk
20
80
240
90
ND
' ND
50
20
50
60
.pCi/1
133][
1. 3x1
20
310
60
ND
ND
ND
ND
50
ND
not available
110
;' 30
30
ND
Pasturage pCi/kg
131I 133I
O3
830 2.7xl03
640 IxlO3
ND ND
i
ND ND'
680 l.SxlO3
4;20 ND
?70 2xl03
ND ND
ND ND
^Activity extrapolated to end of collection time.
**Samples were not available after th\.s date.
ND - Not detectable.
26
-------
456
in milk. ' ' Rather, the effective half-life was about one day
or less (Figure 5). Thus, the estimated potential dose based
upon integration of the daily concentrations was calculated to
be 12 millirad for a child with a 2 gram thyroid.
There are several possible reasons for the rapid decay:
(1) These results are based on individual samples from only
1 or 2 cows. Theoretical values are based on average results
i
from several cows where the results from individual cows
may vary by.several factors. '
(2) The deposition of effluent was very spotty due to the rough
terrain. The cow grazed in a large pasture and varying
amounts of deposition in different areas of the pasture could
have been analogous to changing the feed to uncontaminated
feed (this results in a half-life for l 31I in the milk of about
6 - = .]
1 day )i The cow was given some supplemental feed which
could a^so have influenced the results.
(3) Part of the cow's intake' of radioiodine may' have been due
to inhalation of radioiodine in the particulate, elemental, and/or
methylf!iodine form (shows a. much shorter half-life in milk).
It has b'een reported that 'the deposition of methyl iodine on
pastura,ge is very minimal and that inhalation b,y the cow may
be important. The fraction of methyl iodine present in the
reactor effluent is not known at this time. '.
:\
The other milk results give'yi in Table 10 generally represent
only 1 cow. If the milk from these cows was ilsed for human
consumption, the potential dose for a child with a two gram
l " 4
thyroid', based on the FRC-5 assumptions would be about
20 millirad or less (100 pCil/liter peak milk concentration is
27
-------
300
X.
_l
i
- 200
OC
UJ
H
_J
V.
O
o.
100
>
_ I concentration, in milk as a function
of time.
: A
/ \
/ \
/ \
i \
§
i \
/ \
/ \
I *
/ \
_ 1 «
**^
f ^T^
^ ^^^ ^^
" ^T^ -^
/ X
__ * ^^ Net D»»«elobl«
f **>^^^
-------
equivalent to about 16 miUirad). This dose estimate assumes
.that the peak 131I concentration in milk occurs at about three
to four days when the cow is exposed via ingestion. If the ex-
posure to the cow is by inhalation, the effective half-life of
1 31I in milk is much less than five days and thus the integrated
dose is less.
e. Vegetation Samples
Natural vegetation samples were taken on Highway 25 between
Hancock Summit and Queen City Summit on June 23, to help
delineate the hotline. The vegetation samples south of Coyote
Summit did not show the presence of fresh fission products.
The results of the samples between Queen City Summit and .
Coyote iSummit are given graphically in Figure 6. The high
results near Queen City Summit are possibly due to the increased
elevation in this area. The^ hotline was considered to be 5 to
10 miles from Coyote Summit on the basis of aerial monitoring
and other surveillance results.
Vegetation samples were taken from Sacramento Pass, Nevada
to Garrison, Utah (Figure 41* on July 1 to detect, the area of
cloud passage. Fresh fission products were not detected on
any of the samples. The time delay between possible deposi-
tion and collection of samples would have allowed a factor of
about four decay which may.'explain the absence of fresh fission
products.
Natural vegetation and pastdirage samples were' taken at the
same lo'cations where milk samples were collected and are
reported along with the milk'results in Table 1(9.
29
-------
pC
Concentration of radio -
iodine on natural vegetation
after cloud passage.
I 1 II 1 I.I 1 \ II l
9UEEN CITY
SUMMIT
ACTIVITY
8
RELATIVE GROSS GAMMA
5
Relative gross gamma
activity on natural vegeta
tion after cloud passage.
1 I.I 1 1
4 6 8 10 "12 14 16 18 2O
DISTANCE IN MILES! FROM QUEEN CITY SUMMIT
24
26
Figure 6. Results of vegetation samples taken on Highway 25 foil owing' NRX-A5,
EP-IV, June 23, 1966.
30
-------
f. Water Samples
Water samples from near Alamo, Hiko, Warm Springs, and
Shoshone, Nevada area did not show detectable levels of fresh
fission products.
31
-------
CONCLUSIONS
The effluent from two of the tests (EP-III and IV) in the NRX-A5 series
was detected off-site. The potential dose to the off-site population was
below the standards listed in the AEC Manual Chapter 0524, which
generally follows the FRC guidelines.
The AEC radiation protection standards (RPS) for the average dose to
a suitable sample of the population are;
Average for Suitable Sample Average for Individual
Whole Body - 170 millirem/year 500 millirem/year
Thyroid - 500 millirem/year 1500 millirem/year
The standards for radioiodine concentrations in air in an uncontrolled
area for the principal soluble radioiodines are given in Table 11.
The principal air exposures from EB-III and EP-IV are., given in Table 12.
Comparison of these results with the-radiation standard^ in Table 11
gives the conclusions listed below, ^or comparing areas with significant
population--Ridgecrest, Lathrop Wells, Sunnyside--l/3 of the values
listed in Table 11 should be used.
.1
(1) Based on the instantaneous values, i.e., not averaged
for a year as intended by AEC Manual Chapter 0524, three
of the results are above the RPS for gross unidentified
f ' ) (
isotopes, but are not above the RPS for specific isotopes
(exceptr Goss' Ranch). The'Intent is not to show that the
RPS was exceeded, but rather to show the advantage of
specific isotope analysis.
32
-------
Table 11. Radiation protection standards.
Air Cone. Integrated Air Cone. ' Integrated Air Cone. '
pCi/m3 pCi-sec/m3 pCi-sec/m3
Day
131I(3) 102 8.64 x 106
133I(4) . 103 8.64xl07
Unknown*5^ 102 8.64xl06
Year
3. 16 x 109
3.16 x 1010
3.16 x 109 :'
NOTES: (1) Derived from AEC Manual Chapter 0524 by converting
units of uCi/ml to pCi/m3. The values are based on.exposures
to individuals and should be.reduced by a factor of three if
applied to an average exposure to a sample of the population.
When more than one isotope, is present, the summation of
ratios of quantity of isotope present to respective RPS should
be less than one.
i' i
(2) Derived from the Radiation Protection Standard air con-
centration by integrating it over a period of one (1) day, i.e. ,
multiply pCi/m3 times seconds in a day. The column on the
right is integrated for a year.
(3) The standard for l 311 is based on a child with a two
gram thyroid breathing 3 mi?/day. :
' . ' . . r
(4) The standard for * 33I is based on the standard adult (ICRP).
!,''
(5) Bas,ed on Sr-90, 1-129, Pb-210, Ac-227, Ra-228, Pa-230,
Pu<-241, Bk-249 and alpha emitters not being present as
defined in reference 8. Strontium-90 is assumed not present
because of reactor operating history; if it were present, the
r
value would be 10.
33
-------
Table 12. Principal air concentrations resulting from NRX-A5. *
OJ
EP Location
Gross Beta isij-- I33p;:;;;
pCi/m3 pCi-sec/m3 pCi/m3 pCi-sec/m3 pCi/m3 pCi-sec/m3
Ill Ridgecrest, California***
10 mi. S. of Beatty (Hwy. 95)
(unpopulated)
Lathrop Wells
IV Goss1 Ranch
Coyote Summit (unpopulated)
Sunnyside
Geyser Maint. Station***
2.3
1.9
1. 1
14,4
00
527
1
38
10
2.
1.
8.
9.
7.
1.
8.
IxlO5
2xl05
8xl04
4xl07
8xl06
2xl07
9xlCP
NGS
1.7
2. 2
1. 5xl03
40
15
NGS
1.
1.
9.
5.
1.
IxlO5
8xl05
7x1 06
9xl05
3xl06
NGS
4.2
9.8
3. 3xl03
1. 5xl02
40
NGS
2.
7.
2.
2.
3.
6x1 05
8xl05
IxlO7
2xl06
5xl06
^Results extrapolated to end of collection time.
**The iodine activities for both the prefilter and charcoal cartridge have been added.
###Cloud passage at this location was not noted until after the fact; therefore, gamma spectrum analysis
was not performed on these two samples because the gross beta count did not fall above the control
limit set for determining whether this analysis should be performed.
NGS - Not gamma scanned.
-------
(2) Further, if the integrated concentrations are used, the
result from Goss1 Ranch is equivalent to less than two days
exposure at the RPS level (2nd column from right indicates
1 day of exposure to RPS). AEC Manual Chapter 0524
specifies that concentrations may be averaged over a period
of a year (column on right in Table 11). The RPS concen-
trations are based on continuous exposure and thus are not
strictly applicable to short term air concentrations. The'
concept of integrated concentration guides allows comparison
of short term concentrations to the guides.
The peak external gamma dose from the NRX-A5 series was about
1 millirad at Go,ss' Ranch (based on E-500B survey meter). The
highest dose at a reasonably dense populated area was about 0. 05 milli-
rad at Sunnyside,,, Nevada based on tfye RM-11 results. ,,Both of these
exposures were .from the EP-IV.
The milk samples in this report all dome from ranches 'where the milk
is used locally. '' The age of individuals using the various milk supplies
r- ii *
varies. The term potential dose has been used when it is not actually
known if someone received the dose. Doses varying from the potential
} ' ,T .
dose could result from variation in individuals milk consumption,
biological variability of individuals from the "critical receptor" used
in calculations (child with 2 gram thyroid and iCRP assumptions on
uptake), etc. This frame of "potential dose" also applies to the other
doses or exposures reported in this report.
i
The summation'of doses for several locations are giveri'in Table 13.
This summation includes the dose from cloud passage, inhalation and
ingestion.
35 '
-------
Table 13. Summary of results and doses from NRX-A5.
Location
(Nevada)
Lathrop Wells
Dansby's Ranch,
Lathrop Wells
Goss' Ranch
Sunny side
Kirkeby Ranch/3*
Sho shone
E. J. Cummings,
Baker
EP
III
III
IV
IV
IV
IV
Date
6-8
6-8
6-23
6-23
6-23
6-23
Air
Gross Beta
pCi/m3
1. 1
14,400
138
pCi-sec/m3
8.8xl04
9.4xl07
l.ZxlO7
131!
pCi/m3
2. 2
1. 5xl03
15
pCi-sec/m3
l.SxlO5
9.7xl06
1.3xl06
133!
pCi/m3
9.8
3.3xl03
40
pCi-sec/m3
7. 8xl05
2. IxlO7
3.5xl06
Thyroid
Dose
Inhalation
Child
mR
0.40
2.3
Adult
mR
0. 13
7
0.8
External
Exposure
Rate Total
mR/hr
ND
1.2
0. 02
mR
1
0. 05
.02
.02
Milk
Peak
pCi/1
13l!
No r
50
240
110
1^!
nilk
ND
1300
30
Potential
Ingestion
Dose
millirad
PeakfT)
8
17(8)
18
Actual{(
8(1)
9(4,8)
5(5)
Total
Thyroid
Dose (6)
millirad
< 1
8
8
2
9
5
Notes:
(1) A child of about one year old was present.
(2) Sampler not started till after cloud arrival; dose based on extrapolation to estimated arrival time.
(3) Gamma exposure based on extrapolation from Sunnyside(distance to the minus three power). Total thyroid dose includes contribution from gamma
(4) Youngest child present four years old - assume 4 gram thyroid. exposure and inhalation(inhalation extrapolated from
(5) Youngest child present eight years old - assume 8 gram thyroid. Sunnyside results using distance to the minus two
(6) Based on age of child present. power).
(7) The peak value is based on a child with a 2 gram thyroid drinking 1 liter of milk per day. It is assumed a peak value of 100 pCi per liter in milk
results in an integrated dose of 16 millirads (reference 4).
(8) The dose calculation is based on the observed half-life in milk, about 1 day, rather than the value of 5 days from FRC No. 5 (reference 4).
-------
Although the peak milk concentration, 240 pCi/liter was detected at
Kirkeby's Ranch, it is noted that it might not have resulted in the peak
dose because of the. short effective half-life of the 1 31I in the milk.
Thus the result from the E. J. Cummings Ranch is included in Table 13.
Insufficient data are available to determine the effective half-life in the
Cummings sample,thus a value of about 5 days is used.
Two sets of results are given in Table 13 for Kirkeby's and Cummings1.
One set gives the potential dose for a 1 year old child, the second for
the youngest child known to be present.
A comparison of the two graphs in Figure 6 shows that the 1 31I, 1 33I,
and gross gamma results for vegetation follow the same trend. If
future results also demonstrate this !trend, analysis of vegetation sam-
ples to determine trajectories may be limited to gross gamma. Specific
analysis should still be performed on' selected samples to demonstrate
the presence of fresh fission products and indicate the levels of various
isotopes.
37
-------
REFERENCES
1. "Synopsis of Meteorological Data for the NRX-A5 Reactor EP-III,"
June 1966, U.S. Department of Commerce, ESSA, ARFRO.
2. Recommendations of the International Commission on Radiological
Protection, ICRP Publication 2, 1959.
3. Task Group on Lung Dynamics, Committee II of the ICRP, "Deposition
and Retention Models for Internal Dosimetry of the Human Respiratory
Tract." Health Physics, Vol. 12, No. 2, February 1966, p. 173.
4. Staff Report of the Federal Radiation Council, "Background Material
for the Development of Radiation Protection Standards," Report
No. 5, July 1964.
5'.. Final Report of the Off-Site Surveillance for the NRX-A4/EST, SWRHL-30r.
6. D. S. Barth' and J. G. Veater, "Dairy Farm Radioiodine Study Follow-
ing the Pike Study, " SWRHL-14r, Nov. 23, 1964.
7. C.A. Hawley, "Controlled Environmental Radioiodine Tests at the
National Reactor Testing Station," IDO-12047, February 1966.
8. U.. S. AEC Manual, Chapter 0524J "Standards for Radiation Protection."
9. "Final Report of Aerial Surveillance for the NRX/EST, " Engineering
Development Program, SWRHL, May 31, 1966.
10. D.F. Bunch, "The Comparative Environmental Hazards from a
Release of Methyl Iodine of Elemental Iodine," Idaho Operations
Office, AEC, given at 9th AEC Air Cleaning Conference, Sept. 1966.
38
-------
APPENDICES
Appendix A Thyroid Inhalation Exposure from Radioiodine 39
Appendix B Milk and Associated Feed Results, NRX-A5,
EP-IV, June 23, 1966 42
39
-------
APPENDIX A
Thyroid Inhalation Exposure from Radioiodine
Absorbed dose is the quotient of the energy imparted by ionizing radia-
tion to the matter in an "element of volume. "
Dose rate is the rate at which the energy is absorbed. For tissue
containing a beta emitter the amount of energy absorbed per unit
volume is equal to the energy emitted per unit volume. This assumes
the radioisotope is essentially uniformly distributed in tissue of
uniform composition with dimensions large compared to the range of
the beta particles. These assumptions can be applied to the calcula-
tion of thyroid dose from radioiodines, if an effective energy based on
the thyroid dimensions is used. Thus, for the dose rate (DR):
DR = KEA exp- \ ff t Eq. 1
t eii
Where: DR - The dose rate at time t
K - Conversion parameter
E - Effective energy (Mev) per disentegration (d)
A - Activity at lime deposited in organ (Gi/gan)
\ ff - Effective decay.constant for radioisotope of interest
i t - Time after Deposition in organ
To obtain the infinite or total dose, Aquation 1 must be integrated -with
respect to time between zero and inf'i:nity( oo).
rCO ,
Dose = KEA I exp -X .,. t dt
'o eff
Dose = KEA (-1/X ,, exp -X rr t)'°°
eii eii
o
Thus, Dose = KEA (-1/X ,, (0-1)) '
eff
Dose = KEA/X ., Eq. 2
eii
40
-------
The numerical values for the parameters are:
- 3.7xl010d 8.64xl04 sec 1.602 ergs rad
K - - r _ « ...._._-.. v g-._. y --, - L
Ci-sec day 106 Mev 100 erg/grr
K = 5. IZxlO7 (gram-rad-d/Ci-day-Mev
E - 0. 23 Mev for * 31I (ICRP-2)
,A = X (Ci-sec/M3) x R(M3/sec) x f x l/m(gm) (Assumes no decay
during uptake)
Where: X - integrated air concentration for isotope of interest
R - 2. 32x10 4 M3/sec - breathing rate for average
adult (ICRP)
f - 0. 23 (for iodine) - fraction of inhaled activity reaching
thyroid (ICRP)
m - 20 grams - mass of adult thyroid
A = XRf/m (Ci/gm)
X. = . 693/t ,, - t ,, is the effective half-life in days -7.6 days
eff eff eff '
for 131I (ICRP)
Substituting these parameters into equation 2;
Dose = 5. 12xl07 (gm-rad-d/Ci-day-Mev) x E (Mev/d) x XRf/m) x t £f/. 693(-day);
Dose = 7. 39xl07 XERf t ff/m (rad) Eq. 3
eff .
Substituting the ICRP parameters for 131I and standard man:
D = 7. 39xl07 x 0. 23 x 2. 32xlO"4 x 0. 23 x 7.6 x X
20
Dose (rads) = 3.44xl02 (Ci-sec/M3)^
Converting this to pCi and mrad:
Dose (mrad) = 3. 44xlO'7 (pCi-sec/M3)* for J 311
41
-------
This same calculation can be performed for other isotopes using the
appropriate parameters (ICRP2) . It should also be noted that if more
than one radioiodine isotope is present, the doses should be summed
to obtain total dose. The general equation for this would be (using
equation 3):
Total dose from radioiodines = 7. 39x107 Rf Y E t fr X
£->,. eff
m iodines
*If the dose conversion constant K is rounded to 5. IxlO7 the signifi-
cant digits are 3. 42
42
-------
APPENDIX B
Milk and Associated Feed Results
NRX-A5, EP-IV, June 23, 1966
Location
3 mi. N. Shoshone, Nev.
(Kirkeby Ranch)
1 3 mi. N. Shoshone, Nev.
(Harbecke Ranch)
15 mi.SW Shoshone,.
Nev. (Geyser Rch)
5 mi. S. Baker, Nev.
(E. J. Cummings)
3 mi.S. Baker, Nev.
(Baker Ranch)
Baker, Nevada
' 20 mi.NNW Baker,
Nev. (H.T.Rogers)
Caliente, Nevada
(Young Ranch)
Date
6/24
6/25
6/26
6/27
6/30
7/01
6/26
6/27
6/26
6/27
6/26
6/27
7/01
7/05
6/30
7/01
7/01
6/26
6/27
6/24
Milk pCi/1
1 31 j 1 3 3j
20
80
240
90
ND
ND
50
60
ND
not
avail.
110
not
avail.
ND
50
20
ND
ND
43
1. 3xl03
20
310
60
ND
ND
50
ND
ND
30
ND
ND
ND
ND
ND
Vegetation pCi/kg
1 31 j 1 3 3j
830
640
ND
680
420
ND
890
7.7xl02
ND
ND
ND
ND
ND
ND
ND
ND
2.7xl03
1. OxlO3 past.
ND
1. 5xl03
ND past.
ND
ND
2xl03 grass
ND past.
ND past.
ND past.
ND hay
ND
ND nat.
ND nat.
ND
-------
Location
Nyala, Nevada (Sharp)
Lund, Nevada
(McKenzie)
Moapa, Nevada
(Searles Dairy)
Hiko, Nevada
(Schofield Dairy)
Currant, Nevada
(Manzonie Ranch)
Lockes, Nevada
(Blue Eagle Ranch)
Pioche, Nevada
(Horlacher Ranch)
15 mi.E. Ely, Nev.
(Yelland Ranch)
Garrison, Utah
(Gonders Ranch)
Ogden, Utah
(Maple Leaf Dairy)
Date
6/24
6/25
6/24
6/25
6/24
6/23
6/24
6/24
6/24
6/25
6/24
6/26
6/27
6/30
7/01
6/30
7/01
7/02
7/05
Milk
131I
30
ND
ND
ND
ND
ND .
ND
ND
ND
ND
ND
ND
ND
ND
ND
pCi/1
1 3 3j
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
.ND
ND
ND
ND
Vegetation pCi/kg
1 31 j 1 33j
ND ND
ND ND nat. &
past.
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND
ND ND past.
ND ND hay &
past.
44
-------
Location Date
Mt. Pleasant, Utah
(Brooktown Creamery) 6/29
6/30
7/01
7/02
7/03
Springfield, Utah
(Cache Valley Dairy) 7/01
7/02
7/05
Milk pCi/1 Vegetation* pCi/kg
1 31 j 1 33j 1 31 j 1 33j
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Notes: ND - not detected
Blanks indicate no sample.
Results extrapolated to time of collection.
Past. = Pasture
Nat. = Natural vegetation
45
-------
DISTRIBUTION
- 1 - 15 SWRHL, Las Vegas, Nevada
16 James E. Reeves, Manager, NVOO/AEC, Las Vegas, Nevada
17 Robert H. Thalgott, NVOO/AEC,, Las Vegas, Nevada
18 .Henry G. Vermillion, NVOO/AEC, Las Vegas, Nevada
19 D. H. Edwards, Safety Evaluation, NVOO/AEC, Las Vegas, Nev.
20 D. W. Hendricks, Rad. Safe. Br. , NVOO/AEC, Las Vegas, Nev.
21 Central Mail & Records, NVOO/AEC, Mercury, Nevada
22 A. J. Whitman, NTSSO, NVOO/AEC, Mercury, Nevada
23-24 R. Decker, SNPO, Washington, D. G.
25 D. Smith, SNPO-C, Cleveland, Ohio
26 - 27 J. P. Jewett, SNPO-N, Jackass Flats, Nevada
28 - 31 R. Nelson, SNPO-N, NRDS, Jackass Flats, Nevada
32 William C. King, LRL, Mercury, Nevada
33 Roger Batzel, LRL, Livermore, California
34 H. L. Reynolds, LRL, Livermore, California
35 - 36 H. T. Knight, LASL, Jackass Flats, Nevada
37 P. Gothels, LASL, Los Alamos, New Mexico
38 H. S,. Jordan, .LASL, Los Alamos, New Mexico
39 Charles I. Browne, LASL, Los Alamos, New Mexico
40 William E. Ogle, LASL, Los Alamos, New Mexico
41 H. G. Simens, NTO, Aerojet-General Corp. , Jackass Flats, Nev.
42 G. Grandy, WANL, NRDS, Jackass Flats, Nevada
43-44 E. Hemmerle, WANL, Pittsburgh, Pennsylvania
45 -46 S. Z. Mikhail, NRDL, San. Francisco, California
47 - 48 M. I. Goldman, NUS, Washington, D. C.
49 - 50 J. Mohrbacher, Pan Am. World Airways, Jackass Flats, Nev.
51 P. Allen, ARL, ESSA, Las Vegas, Nevada
-------
52 H. Booth, ARL, ESSA, Las Vegas, Nevada
53 C. Anderson, EG&G, Las Vegas, Nevada
54 Byron Murphey, Sandia Corporation, Albuquerque, New Mexico
55 Brig. Gen. Edward B. Ciller, DMA, USAEC, Washington, D. C.
56 - 57 Chief, NOB/DASA, NVOO/AEC, Las Vegas, Nevada
58 - 62 Charles L. Weaver, USPHS, NCRH, Rockville, Md.
63 Victor M. Milligan, REECo, Mercury, Nevada
64 - 65 DTIE, USAEC, Oak Ridge, Tennessee
------- |