SWRHL-18r
FINAL REPORT OF OFF-SITE SURVEILLANCE
FOR THE
by the
South-western Radiological Health Laboratory
U. S. Public Health Service
Department of Health, Education, and Welfare
Las Vegas, Nevada
October 8, 1965
This surveillance performed under a Memorandum of
Understanding (No. SF 54 373)
for the
U. S. ATOMIC ENERGY COMMISSION
-------
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 informa-
tion contained in this report, or that the use of any information, appa-
ratus, method, or process disclosed in this report may not infringe
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, disseminates,
or provides access to, any information pursuant to his employment or
contract with the Commission, or his employment with such contractor.
001
-------
SWRHL-18r
FINAL REPORT OF OFF-SITE SURVEILLANCE
FOR THE
NRX-A3 EXPERIMENT
by the
Southwestern Radiological Health Laboratory
U. S. Public Health Service
Department of Health, Education, and Welfare
Las Vegas, Nevada
Copy No. 1
O. R. Placak, Officer in Charge
SWRHL, Las Vegas, Nevada
October 8, 1965
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
radiation surveillance in support of the NRX-A3 experiments of
April 23, May 20 and May 28, 1965. This support consisted of
tracking the effluent, monitoring radiation dosage to the off-site
population and collecting environmental samples in downwind areas.
Although off-site contamination occurred as a result of the NRX-A3
tests, the data collected indicate that radioactivity levels did not
exceed the safety criteria established by the Atomic Energy Com-
mission for the off-site population.
-------
TABLE OF CONTENTS
ABSTRACT i
TABLE OF CONTENTS ii
LIST OF TABLES iv
LIST OF FIGURES v
INTRODUCTION 1
I. OPERATIONAL PROCEDURES 3
A. EXTERNAL MEASUREMENTS 3
1. Ground Monitoring 3
2. Dose Rate Recorders 3
3. Aerial Cloud Tracking 3
4. Film Badges 4
B. ENVIRONMENTAL MEASUREMENTS 4
1. Air Samples 4
2. Milk and Water Samples 7
II. RESULTS 9
A. NRX-A3, EP4, April 23, 1965 9
1. Ground Monitoring 9
2. Dose Rate Recorders 9
3. Film Badges 9
4. Air Samples 12
5. Milk Samples 12
B. NRX-A3, EPS, May 20, 1965 12
1. Ground Monitoring 12
2. Dose Rate Recorders 12
3. Film Badges 15
4. Air Samples 15
5. Milk Samples 15
11
-------
C. NRX-A3, EP6, May 28, 1965 19
1. Ground Monitoring 19
2. Dose Rate Recorders 19
3. Film Badges 19
4. Air Samples 19
5. Milk Samples 19
6. Vegetation Samples 23
in. CONCLUSIONS 24
DISTRIBUTION
111
-------
LIST OF TABLES
Table 1. Meteorological data for NRX-A3, EP4 10
Table 2. Analysis of air samples collected following
NRX-A3, EP4 13
Table 3. Meteorological data for NRX-A3, EP5 14
Table 4. Dose rates occurring off the test range complex
on May 20, 1965 15
Table 5. Analysis of air samples collected following the
NRX-A3, EPS 17
Table 6. Analysis of milk samples collected following
NRX-A3, EP5 18
Table 7. Meteorological data for NRX-A3, EP6 20
Table 8. Analysis of air samples collected following
NRX-A3, EP6 22
Table 9. Analysis of milk samples collected folio-wing
NRX-A3, EP6 23
Table 10. Peak external gamma doses detected off the test
range complex following NRX-A3, EP 4 and 5 24
Table 11. Peak iodine concentrations as measured by char-
coal cartridges 25
Table 12. Thyroid dose due to inhalation 26
IV
-------
LIST OF FIGURES
Figure 1. Reactor in testing position. 2
Figure 2. Air surveillance network stations in Nevada. 5
Figure 3. Special sample locations following NRX-A3, EP4. 11
Figure 4. Special sample locations following NRX-A3, EP5. 16
Figure 5. Special sample locations following NRX-A3, EP6. 21
-------
INTRODUCTION
As a part of the ROVER Program, testing and disassembling of a
series of reactors designated NRX-A is being conducted under the
Nuclear Engine for Rocket Vehicle Application (NERVA) Project at
the Nuclear Rocket Development Station. The subject of this report
is the off-site surveillance provided by the Public Health Service
(PHS) for the Atomic Energy Commission (AEC) in support of the
NRX-A3. Experimental Plans 4, 5 and 6 were conducted at Test
Cell A on April 23, May 20 and May 28, 1965. The results of each
test will be discussed in a separate section of this report. The
reactor was tested in an upright position so that the hydrogen coolant
exhausted upward along with escaping fission products (see Figure 1).
Under a Memorandum of Understanding with the Atomic Energy Com-
mission, the U. S. Public Health Service conducts a program of ra-
diological monitoring and environmental sampling in the off-site
area surrounding the Nevada Test Site and the Nellis Air Force
Range. The overall complex of the Nevada Test Site (NTS) and the
Nellis Air Force Range (NAFR) includes the Nuclear Rocket Develop-
ment Station (NRDS) and the Tonopah Test Range (TTR) and for sim-
plicity will be called the test range complex throughout this report.
-------
Figure 1. Reactor in testing position.
2
-------
I. OPERATIONAL PROCEDURES
A. EXTERNAL MEASUREMENTS
1. Ground Monitoring
Ground monitors tracked the reactor effluent passage with
portable instruments. Each monitor was equipped -with an
Eberline E-500B, a Precision Model 111 Standard "Scintillator",
and a Victofeen Radector Model No. AGB-50B-SR. ,
The Eberline E-500B has a range of 0 to 200 milliroentgens per
hour (mR/hr) in four scales with an external halogen filled GM
tube and a 0 to 2000 mR/hr range from an internal Anton 302
tube. The Precision Model 111 "Scintillator" is used primarily
for low level detection ^and has a range of 0 to 5 mR/hr in six
scales. The Radector has a range of 0 to 50,000 mR/hr on two
scales. This instrument employs an inert gas ionization cham-
ber. Errors associated with these instruments are of the order
of +20%.
2. Dose Rate Recorders
Eberline RM-11 dose rate'recorders are placed at twenty-one
stations around the test range complex. These recorders utilize
a Geiger tube detector to document radiation levels at specific
locations. The instrument has a 0.01 to 100 mR/hr range and
the gamma dose rate is recorded on a 30-hour strip chart. The
RM-11 is accurate to +20% as calibrated with a l 37Cs source.
3. Aerial Cloud, Tracking
An Air Force U3-A aircraft and crew, together with two Public
Health Service monitors equipped with portable instruments
-------
identical to those of the ground monitors, tracked the reactor
effluent to position ground monitors. Public Health Service
cloud sampling aircraft were also used as aids in cloud tracking.
Their primary purpose, however, was cloud sampling in order
to determine cloud size and inventory. The results of their sam-
pling are reported separately by the SWRHL Engineering Devel-
opment Program.
4. Film Badges
The PHS maintained 75 film badge stations off the test range
complex and assigned badges to 165 off-site residents during
the month of April. During May, 62 film badge stations were
established and 109 personnel film badges -were issued. The
badge used is DuPont type 555 film. This film is 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.
B. ENVIRONMENTAL MEASUREMENTS
1. Air Samples
Ninety-five routine Gelman "Tempest" air samplers were in
operation in the western United States. Thirty -two of these are
located in Nevada and are presented in Figure 2. Supplementary
air samplers were established for the NRX-A3 experiments and
their locations are shown in the Results section of each experi-
ment. The "Tempest" air samplers are designed to utilize 4"
Whatman No. 541 prefilters and MSA type BM 2306 charcoal
cartridge filters. The average flow rate is approximately 10 cfm.
The total volume of air sampled is calculated from an average
vacuum reading and the total time of sampling.
-------
N E \V A D A
AIR 3*Mn.CN WITH PREFILTER
AIR I AMPLE ft WITH PREFILTER AND
CHARCOAL CARTRIDGE
Figure 2. Air surveillance network stations in Nevada.
5
-------
The prefilters were counted for gross beta and alpha activity
with a Beckman wide beta proportional counting system. This
system has a detection efficiency of 45% for 0. 54 Mev beta par-
ticles and has a background of 6 + 1 counts per minute.
All air samples were counted for gross beta activity as soon as
possible after receipt at SWRHL. Samples which indicated beta
concentrations in excess of 20 pCi/m3 were recounted frequently
within the following 48 hour period. These samples were then
held for routine counts at 5 and 12 days after collection. The
computational procedure employed depends upon the assumption
that a decay constant can be found for each individual sample and
that this decay constant can then be used to extrapolate the activ-
ity to the end of the collection period. For this purpose, the
general decay equation A/A = e is employed. For samples
showing less than 10 pCi/m3 at time of first count, the 5 and 12
day counts are utilized for computing the decay factor. For sam-
ple concentrations exceeding the 10 pCi/m3 the earlier counts
are used for extrapolation purposes.
Since it is 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
™ ^ ^ c*
are also reported in - 5 - to indicate the potential gross beta
inhalation exposure at each location. This unit is obtained by
multiplying pCi/m3 by the sampling time in seconds.
All charcoal cartridges were analyzed for gamma isotopes by
placing each directly on a 4"x 4" sodium iodide crystal coupled
to a 400 -channel pulse height analyzer set to view energies from
0 to 2 Mev. The activity on the cartridge should represent the
gaseous fission products such as isotopes of iodine. Overall
-------
detection efficiency for this geometry is about 18% at 0.53 Mev
(133I). The minimum detectable activity for J 311, 132I, 133I
and * 35 I is about 200 picocuries total on the cartridge, at count
time, with an accuracy, at this level, of -f 50% for l 31I, l 32 I,
133I, and +100% for 135 I.
2. Milk and Water Samples
After each release of activity from NRDS, milk samples are col-
lected from dairies (processing plants), producing dairy farms,
and farms producing milk for their own consumption. Each sam-
ple is counted for 50 minutes. No attempt is made to recount
samples giving low positive values. The lower limit of detection
for gamma emitters in milk samples is 20 picocuries per liter
(pCi/1) at time of count, and all results below that value are re-
ported as < 20 pCi/1.
All liquid samples are counted in 3. 5 liter inverted well aluminum
beakers -which are placed on top of a 4"x 4" crystal coupled to a
400-channel gamma pulse height analyzer. Overall detection
efficiency for the 0. 364 Mev photopeak of 1 31I is 6.4%. A matrix
technique is employed to compute the interference due to the
presence of other isotopes. The input to this matrix is variable,
allowing for the simultaneous determination of any eight nuclides
for -which detection efficiencies and interference factors have
been obtained. Actual computation is performed by an IBM 1620
computer.
Water samples are analyzed for gross beta activity by slowly
evaporating an aliquot to dryness in a 2" diameter stainless steel
planchet and counting the beta activity in a low background counter.
-------
Vegetation samples were obtained at all milk sampling locations.
An attempt was made to make the samples representative of the
cows' feed; however, the samples were taken primarily as early
indicators of where milk might be contaminated and were not in-
tended to yield a cow intake-excretion formula.
-------
II. RESULTS
Results of the three NRX-A3 power tests will be reported in separate
sections. All of the three experiments yielded low levels of radio-
activity off the test range complex.
A. NRX-A3, EP4, April 23, 1965
The reactor was tested at full power for approximately four minutes
commencing at 1254 PST. Aerial tracking of the effluent from the
test indicated a hot line bearing of 160 from NRDS. Meteorological
observations on the test day are presented in Table 1. Environmen-
tal sampling locations established after EP4 are shown in Figure 3.
1. Ground Monitoring
Ground monitors detected cloud passage with portable instru-
ments at Pahrump between 1500 and 1545 hours PST. Net peak
dose rate during this interval was less than 0. 03 mR/hr and
occurred at 1530. The external whole body dose due to cloud
passage was less than 0.03 millirem.
2. Dose Rate Recorders
Dose rate recorder data collected following EP4 did not indicate
dose rates above background.
3. Film Badges
Due to the low dose rates encountered off the test range complex,
no off-site film badges were collected immediately following EP4.
Badges collected since that time, however, have had no exposure
which could be attributed to the EP4 test.
-------
Table 1. Meteorological data supplied by the U.S. Weather Bureau.
for NRX-A3, EP4.
Sky Condition: Clear Clouds: Cloudless Visibility: Unrestricted
Upper Air Data at: Nuclear Rocket Development Station, 1259 PST,
4/23/65
Height
Wind
Pressure
(Ft.MSL) (Deg/Kts) (mb)
Temper- Dew Relative
ature Point Humidity
SFC 3615
3980
5000
5066
5450
6000
7000
7920
8000
9000
10000
10341
11000
11100
12000
12550
13000
13080
13530
14000
15000
030/05
100/06
100/07
100/07
090/07
090/08
070/09
060/11
060/11
050/07
070/06
040/07
360/09
360/09
350/13
340/17
330/22
330/22
320/27
320/26
330/27
895
884
851
850
836
821
792
766
763
736
709
700
682
680
656
644
633
631
620
608
586
23.8
21.0
17.8
17.6
16.6
14.7
11.2
8.2
8.0
5.2
2.3
1.3
-0.6
-0.9
-2.3
-3. 1
-2.7
-2.6
-2.9
-4.0
-6.2
- 9.6
MB
MB
MB
-10.2
-10.9
-11.0
-10.7
-10.8
-11.0
-11.9
-12.4
-13.2
-13. 1
-18.3
-21,3
MB
MB
MB
MB
MB
10
(12)
(12)
(12)
15
16
20
25
25
30
34
35
38
39
28
22
(14)
(14)
(14)
(14)
(15)
SFC = Surface
MB = Motor Boating - dewpoint was below the limitations of the in
strumentation.
( ) = Numbers in parentheses are the result of calculations based
on assumed atmospheric conditions.
10
-------
DEATH VALLEY OCT.
\
O Air sampler with prefilter
9 Air sampler with prefilter &
T charcoal cartridge
IB Temporary air sampler
^ Milk sampling location
A Dose rate recorder
\
SHOSHONE.
Figure 3. Special sample locations following NRX-A3, EP4.
11
-------
4. Air Samples
Air samples from several routine stations and four temporary
locations were collected following EP4. (See Figure 3). Samples
collected following EP4 with gross beta activity above background
levels are presented in Table 2. Air samples obtained following
EP4 from Beatty, Death Valley Junction and Shoshone, did not
indicate gross beta activity above background levels.
5. Milk Samples
A milk sample and a sample of the cow's feed were obtained at
Pahrump on the morning of April 24. Analysis of these two sam-
ples indicated no radioiodine.
B. NRX-A3, EPS, May 20, 1965
The reactor was conducted at full power in the time interval 1032 to
1046 hours PDT. Aerial tracking of the effluent indicated a hot line
o o
bearing lying between 40 and 60 on the test range complex. Meteor-
ological data obtained by the U.S. Weather Bureau is presented in
Table 3.
1. Ground Monitoring
Ground monitors located on Highway 25 detected cloud passage
with portable instruments. A summary of the ground monitoring
data is presented in Table 4. The maximum dose due to cloud
passage at any monitored location was less than 0. 03 millirem.
2. Dose Rate Recorders
Dose rate recorder data collected from Diablo, Alamo, Pioche
and Caliente on the morning of May 21 did not indicate dose rates
above background following EP5.
12
-------
Table 2. Analysis of air samples collected following the NRX-A3, EP4, reported in pCi/m3 at end of collection.
On Time Off Time ,, ,
Location Volume
ic T^- ->\ Date Date 3
(See Fig. 2) (pST) (pST)
Lathrop Wells 1045,4-23 1555,4-23 106
HW7r 9*1' l°™\fSE 1407,4-23 1545,4-23 . 17
of Lathrop Wells
HW/'T 9JL' 17^UifSE 1350,4-23 1555,4-23 20
of Lathrop Wells
HW7r 91' 23^NfSE 1400,4-23 1600,4-23 20
of Lathrop Wells
Hwy. 95, 25 mi ESE 1404,4-23 1605,4-23 18
of Lathrop Wells
Pahrump, 1000,4-23 1120,4-24 474
Nevada
Prefilter Integrated Gamma Pulse Height Analysis
Gross Beta Gross Beta Col- pCi/m at End of Collection
Concentration Concentration lector
PCi/m3 pCi-sec/m3 131I 132I 133I 135I
3.1 5.9x10* P ND ND ND ND
C ND ND ND ND
34 2.0xl05
110 8.4xl05
4.7 3.4xl04
36 2.6xl05
6.3 5.7x10^ £ 2'4 2'8 14 ^D
C 1.2 1.1 3.7 ND
ND = Non Detectable
P = Prefilter
C = Charcoal Cartridge
-- = Not Analyzed
-------
Table 3. Meteorological data supplied by the U.S. Weather Bureau
for NRX-A3, EPS.
Sky Condition: High, Thin Broken Clouds: . 6 Cirro Stratus
Visibility: Unrestricted
Upper Air Data At: Nuclear Rocket Development Station, 1016 PDT,
5/20/65
Height
Wind
Pressure
(Ft. MSL) (Deg/Kts) (mb)
Temper- Dew Relative
ature Point Humidity
SFC 3615
3980
4000
4870
5000
6000
7000
8000
8740
9000
10000
10180
11000
12000
12230
13000
14000
15000
190/07
210/02
210/11
210/04
200/05
210/04
280/05
300/06
280/06
260/07
230/10
240/10
240/11
250/12
250/13
260/15
280/18
270/20
889
879
878
-850
•847
816 N
787
758
738
731
704
700
679
654
648
630
606
583
23.2
20.9
20.8
18.2
18.0
15.1
12.4
9.6
7.5
7.0
5.0
4.7
3.0
1.0
0.4
-1.0
-3.0
-4.8
- 5.8
- 6.7
- 6.9
- 6.5
- 6.7
- 7.7
- 8.2
- 9.5
-10.8
-11.2
-14.0
-14. 2
-16. 1
-19.0
-19.5
MB
MB
MB
14
15
15
18
18
20
23
25
26
26
24
24
23
21
21
(14)
(14)
(15)
SFC = Surface
MB = Motor Boating - dewpoint -was below the limitations of the in
strumentation.
( ) = Numbers in parentheses are the result of calculations based
on assumed atmospheric conditions.
14
-------
Table 4. Dose rates occurring off the test range complex on May 20,
1965.
Time of Dose Time of _
Net Peak
Location Rates Greater Than Peak Dose
.__... T-> i j -r, ^ Dose Rate
(See Figure 4) Background Rate i
(PDT) (PDT) (n*/hr)
Goss Ranch 1500-1520 1510 <0.03
Coyote Summit 1455-1540 1532 0.06
Hancock Summit 1459-1507 1505 <0.03
Crystal Spring 1525-1548 1542 < 0. 03
3. Film Badges
Due to the low dose rate encountered off the test range complex,
no off-site film badges were collected immediately following EP5.
Badges collected since that time, however, have had no exposure
which could be attributed to the EP5 test.
4. Air Samples
Air samples from several routine stations and three temporary
stations were collected following EPS. (See Figure 4). Samples
collected following EP5 that contained fresh fission products are
presented in Table 5. Air samples collected from Pioche,
Caliente and Warm Springs Ranch did not contain fresh fission
products.
5. Milk Samples
Milk samples were obtained following EP5 from Pioche, Caliente,
Hiko and Alamo; milk from Hiko contained radioiodine for several
weeks following the experiment. Barium-140 was detected on
several pasture samples collected in support of the milk sampling
program. Since 140Ba is generally not detected off-site from
15
-------
WARM SPRINGS
OYOTE SUMMI
GOSS RANCH
L-i
HANCQCK SUMMIT
ALAMO
BEATT*_J TEST CELL A
WARM
SPRINGS RN
LATHROP . I
^ UICTI ic t — _ — — — j
I J
Milk sampling
location
Dose rate
recorder
Temporary air
sampler
Air sampler with
refilter & char, cart
Figure 4. Special sample locations following NRX-A3, EPS.
16
-------
Table 5. Analysis of air samples collected following the NRX-A3, EPS, reported in pCi/m3 at end of collection.
On Time Off Time ., . Prefilter
Location Volume _ _ ^
._ _. . . Date Date •» Gross Beta
(See Flg" 4) (PDT) (PDT) m Concentration
pCi/m3
Diablo 0655,5-20 0700,5-21 487 22
Go ss Ranch 1330,5-20 1600,5-20 45 76
Coyote Summit 1326,5-20 1607,5-20 27 290
Hancock Summit 1330,5-20 1605,5-20 26 88
Hiko 0805,5-20 1700,5-20 201 41
Alamo 0710,5-20 1700,5-20 203 38
Integrated
Air
Concentration
pCi-sec/m3
1. 9xl06
6.8xl05
2.8xl06
8. 3xl05
1.3xl06
1.3xl06
Col-
lector
P
C
P
C
P
C
P
C
P
C
P
C
Gamma Pulse Height Analysis
pCi/m at end of collection
131j 132j 133I 135I
ND
ND
12
2.4
41
41
15
5.8
7. 0
0. 95
4.6
ND
3. 3
ND
13
ND
48
33
15
ND
7.0
1. 0
5.4
ND
0.82
ND
18
ND
100
67
30
ND
7.0
1. 7
0.94
ND
ND
ND
9.3
3.4xl02
67
41
17
21
ND
ND
ND
ND
ND = Non Detectable
P = Prefilter
C = Charcoal Cartridge
-------
NRDS activities, it is believed that this contamination is due to
another nuclear event. Furthermore, 131Iwas contained in
milk collected around May 25 from the Pasteurized Milk Network
throughout the United States. Analysis of the data indicate the
generalized contamination to be due to fallout from a Chinese
nuclear detonation on May 14, 1965. Analysis of milk samples
is presented in Table 6.
Table 6. Analysis of milk samples collected following EP5.
n Presence of Milk Radioassay
Location , Radioiodine in Data - pCi/1
Collected 131j
Horlacher Ranch
Pioche, Nevada
Young Ranch
Caliente, Nevada
Stewart Dairy
Alamo, Nevada
Schofield Dairy
Hiko, Nevada
5/21/65
5/21/65
5/21/65
5/24/65
5/21/65
5/24/65
5/26/65
5/28/65
6/02/65
6/08/65
6/16/65
6/25/65
ND
ND
ND
ND
P
P
--
P
--
P
P
ND
ND
ND
ND
ND
ND
50
70
50
60
90
60
30
ND = Non Detectable
P = Present
- - = Sample not Obtained
Samples collected after 6/25/65 reflected contamination due to
Phoebus 1A effluent passage. The sample analyses are reported
in "Final Report of Off-Site Surveillance for the Phoebus 1A
Experiment", SWRHL-19r.
18
-------
C. NRX-A3, EP6, May 28, 1965
The reactor was tested at intermediate power levels in the approxi-
mate time interval 1030 to 1100 hours PDT. Aerial tracking of the
effluent indicated a hot line bearing of 250 on NRDS. Meteorological
observations on the test day are presented in Table 7.
1. Ground Monitoring
Ground monitors did not detect dose rates greater than back-
ground on the test day. Monitored locations included Lathrop
Wells, Beatty, and Highway 95 bet-ween these towns.
2. Dose Rate Recorders
Dose rate recorder data from Lathrop Wells and Beatty did not
indicate dose rates greater than background on the day and night
of May 28.
3. Film Badges
Since no dose rates greater than background were encountered
off the test range complex, no off-site film badges were collected
immediately following EP6. Badges collected since that time,.
however, have had no exposure which could be attributed to the
EP6 test.
4. Air Samples
Air samples were collected from the Lathrop Wells and Beatty
routine stations and from one temporary station folio-wing EP6.
(See Figure 5). Of the air samples collected following EP6, only
the Lathrop Wells charcoal cartridge contained radioiodine. A
summary of the results is shown in Table 8.
5. Milk Samples
Milk samples were obtained at two locations folio-wing EP6. Sam-
ple analyses are reported in Table 9-
19
-------
Table 7. Meteorological data supplied by the U.S. Weather Bureau
for NRX-A3, EP6.
Sky Condition: Clear Clouds: Cloudless Visibility: Unrestricted
Upper Air Data at: Nuclear Rocket Development Station, 1030 PDT,
5/28/65
Height
(Ft.MSL)
SFC 3615
4000
4980
5000
6000
6726
7000
8000
9000
10000
10295
11000
12000
13000
13287
14000
15000
Wind
(Deg/Kts)
080/12
090/13
090/13
090/12
080/12
050/11
020/08
020/09
330/09
340/03
350/04
040/09
040/07
020/09
020/09
030/05
310/05
Pressure
(mb)
895
882
850
849
818
798
790
761
734
706
700
681
655
631
624
607
585
Temper
ature
(°C)
25.4
21.5
17.8
17.7
14.8
13.0
12. 3
10.0
7.7
5. 2
4.6
2.6
-0.2
-3.4
-4.3
-4.9
-5.9
Dew Relative
Point Humidity
(°C) (%)
- 2.2
- 6.2
- 6.2
- 6.3
- 6.7
- 7.1
- 7.7
- 8.7
-10.2
-10.6
-10.7
-11.3
-12.2
-12.3
-12.7
-18.0
MB
16
15
19
19
22
24
24
26
27
31
32
35
40
50
52
35
(15)
SFC = Surface
MB = Motor Boating - dewpoint was below the limitations of the in-
strumentation.
( ) = Numbers in parentheses are the result of calculations based
on assumed atmospheric conditions.
20
-------
+ TEST CELL A
NRDS
DEATH VALLEY JCT.
X
Air sampler with prefilter
and charcoal cartridge
Temporary air sampler
Milk sampling location
Dose rate recorder
\
SHOSHONE,
Figure 5. Special sampling locations following NRX-A3, EP6.
21
-------
Table 8. Analysis of air samples collected following the NRX-A3, EP6, reported in pCi/m3 at end of collection.
On Time Off Time „ , Prefilter
Location _ ^ _ ^ Volume ,-, „
,„ „. ... Date Date , Gross Beta
(See Fig. 5) (pDT) (pDT) m3 Concentration
pCi/m3
Lathrop Wells 0735,5-28 1350,5-28 117 .51
1355,5-28 0635,5-29 342 .54
HW/T9*i 15 w1 ^ 1055,5-28 1335,5-28 27 11
of Lathrop Wells
Beatty 0722,5-28 1353,5-28 137 .47
1353,5-28 0855,5-29 315
Integrated Gamma Pulse Height Analysis
Air Col- pCi/m at end of collection
Concentration lector
13lT 132T 133j 135T
pCi-sec/mJ x j. j. j.
1'2X1°4 C ND
3-2xi°4 c r,
C 0.6
1-lxlO5 ^ ^
1'1X1°4 C ND
C ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
P = prefilter; C = charcoal cartridge
ND = Non Detectable
-- = Not Analyzed
-------
6. Vegetation Samples
Vegetation samples were collected in the area southwest of the
NRDS before and after the test. Analyses of these samples indi-
cated that contamination of the area existed before the experiment
and that levels were not appreciably increased.
Table 9. Analysis of milk samples collected following EP6.
Location
(See Figure 5)
Dansby Ranch
Peacock Ranch
Springdale, Nevada
T-. ... Presence of ,,.,, „ ,.
Date _.,.... . Milk Radioassay
Radioiodme in --•/•,
Collected _ . Data - pCi/1
Feed
6/03/65
5/29/65
6/03/65
6/09/65
6/17/65
6/25/65
7/07/65
131I
ND
P ND
70
40
P 50
ND
ND
133I
ND
ND
ND
ND
ND
--
ND
ND = Non Detectable
-- = Sample not Obtained
P = Present
23
-------
in. CONCLUSIONS
The effluents from the NRX-A3 Experimental Plans 4, 5 and 6 were
detected off the test range complex. The levels represented small
fractions of the guides cited in the AEC Standards for Radiation Pro-
tection.
The radiation dose standard for external whole body exposure to an
individual is 500 millirem per year. The peak external gamma
doses detected following Experimental Plans 4 and 5 are presented
in Table 10. As seen from the table, the exposures were small com-
pared to the protection guide. As mentioned previously, dose rates
greater than background were not detected off-site following Experi-
mental Plan 6.
Table 10. Peak external gamma doses detected off the test range
complex following NRX-A3, EP4 and 5.
Location Dose
(See Figures 3 and 4) Millirem
EP4 Pahrump, Nevada < 0.03
EPS Coyote Summit (unpopulated) <0.03
Since the dose rates at monitored locations returned to background
following cloud passage, it is assumed that the infinite exposure at
the locations due to ground deposition was negligible.
Peak iodine air concentrations as measured by charcoal cartridges
off the test range complex are presented in Table 11. The values
U.S. Atomic Energy Commission Manual Chapter 0524, Standards
for Radiation Protection
24
-------
may be compared to the AEC Standards for soluble iodine concentra-
tions, which are also presented. The standards represent concentra-
tions of radioactivity that should not be exceeded on a continual basis.
For the purpose of applying these standards, radioactivity concentra-
tions in effluents may be averaged over periods up to one year.
Table 11. Peak iodine concentrations as measured by charcoal car-
tridges.
Test
EP4
EPS
EP6
Location
(See Figs. 3,4 and 5)
Pahrump
Coyote Summit
(unpopulated)
Lathrop Wells
AEC air concentration
protection standards
Gamma pulse height analysis
pCi/m3 at end of collection
1 31 j- 132j 1 33j 1 35 j
1.2
41
0,6
IxlO2
1.1 3.7 ND
33 67 41
ND 0.7 ND
8xl03 l.xlO3 4xl03
By applying conversion factors developed by Ralph S. Decker , one
may estimate the thyroid dose due to inhalation of radioiodines,
assuming a person was present during cloud passage. The factors
are applied to char coal-measured peak radioiodine values from
Tables 2, 5 and 8. Picocurie-seconds/meter3 are obtained by mul-
tiplying the sampling time in seconds by the reported pCi/m3 value. .
The data are presented in Table 12.
The AEC standard for thyroid exposure is 1500 millirem per year
to an individual. The calculated values presented are negligible when
compared to the standards.
2
Estimate of Thyroid Dose Due to Inhalation During Cloud Passage,
Ralph S. Decker, Chief, Safety Branch, Space Nuclear Propulsion
Office - unpublished report, June 1965.
25
-------
Table 12. Thyroid dose due to inhalation.
T . Conversion Factors Thyroid dose
Location i3iT IIST ,
I ijjj due to
Test (See Figs. 3, 3.42xlO'7millirad 9.21x10^millirad Inhalation of
4 and 5) ' " •• ', 3 • _. • •/• 3 • i3iT ,
pCi-sec/m3 pCi-sec/m^ J I and
millirad
pCi-sec millirad pCi-sec millirad
m3 to thyroid m3 to thyroid
EP4 Pahrump 1. IxlO5 < 0. 1 3.4xl05 < 0. 1 < 0. 1
EPS Coyote Summit
(unpopulated) 4.0xl05 0.14 6.5xl05 < 0. 1 < 0. 2
EP6 Lathrop Wells 3.6xl04 < 0. 1 4. 2xl04 < 0. 1 < 0. 1
Milk sampling following Experimental Plans 5 and 6 indicated contam-
ination due to NRX-A3 effluent. In each case, milk from one of the
sampled locations indicated radioiodine concentrations. As seen in
Tables 6 and 9, the levels did not exceed 100 pCi/1 of l 31I. The values
may be compared to guidance provided by the Federal Radiation Coun-
cil (FRC) Report No. 2 . An average daily intake of 100 pCi of 1 31I
will meet the FRC Radiation Protection Guide of 0. 5 rem/year to the
thyroid for averages of suitable samples of an exposed population
group. Since the milk sample analyses did not exceed 100 pCi/1 l 31I
%
and levels were above background for approximately one and 1/2
months, it is concluded that a negligible portion of 0. 5 rem was pre-
sented to the public.
"Background Material for the Development of Radiation Protection
Standards" Report No. 2 of the Federal Radiation Council, Sept. 1961.
26
-------
DISTRIBUTION
1 - 15 SWRHL, Las Vegas, Nevada
16 James E. Reeves, Manager, NVOO, AEC, Las Vegas, Nevada
17 R. H. Thalgott, NVOO, AEC, Las Vegas, Nevada
18 O. H. Roehlk, NVOO, AEC, Las Vegas, Nevada
19 H. G. Vermillion, NVOO, AEC, Las Vegas, Nevada
20 Col. E. G. Halligan, DASA, NVOO, AEC, Las Vegas, Nevada
21 Central Mail and Records, NVOO, AEC, Las Vegas, Nevada
22 C. M. Bacigalupi, LRL, Mercury, Nevada
23 Bryce L. Rich, LRL, Mercury, Nevada
24 R. H. Goeckermann, LRL, Livermore, California
25 J. W, Gofman, LRL, Livermore, California
26 H. T. Knight, LASL, Jackass Flats, Nevada
2? Fred Sanders, LASL, Jackass Flats, Nevada
28 Keith Boyer, LASL, Los Alamos, New Mexico
29 Charles I. Browne, LASL, Los Alamos, New Mexico
30 W. E. Ogle, LASL, Los Alamos, New Mexico
31 H. S. Jordan, LASL, Los Alamos, New Mexico
32 L. D. P. King, LASL, Los Alamos, New Mexico
33 Orin Stopinski, LASL, Los Alamos, New Mexico
34 D. L. Snow, DRH, PHS, Washington, B.C.
35 J. G. Terrill, Jr., DRH, PHS, Washington, D.C.
36 Bernd Kahn, RATSEC, Cincinnati, Ohio
37 Raymond Moore, DRH, PHS, Dallas, Texas
38 Vincent Vespe, ALOO, AEC, Albuquerque, New Mexico
39 G. M. Dunning, AEC, Washington, D.C.
40 R. E. Baker, AEC, Washington, D.C.
41 J. S. Kelly, AEC, Washington, D.C.
-------
42 Brig. Gen. D. L. Crowson, DMA, AEG, Washington, D.C.
43 G. J. Ferber, USWB, MRPB (R-3.3), Washington, D.C.
44 P. W. Allen, USWB, NVOO, AEG, Las Vegas, Nevada
45 F. D. Cluff, USWB, NVOO, AEG, Las Vegas, Nevada
46 H. Mueller, USWB, NVOO, AEG, Las Vegas, Nevada
47 M. I. Goldman, NUS, Washington, D.C.
48 B. P. Helgeson, SNPO-N, Jackass Flats, Nevada
49 R. F. Dickson, SNPO-N, Jackass Flats, Nevada
50 David Smith, SNPO-C, Cleveland, Ohio
51 J. M. Wright, SNPO-N, Jackass Flats, Nevada
52 Percy Griffith, SNPO-N, Jackass Flats, Nevada
53 R. S. Decker, SNPO, USAEC, Washington, D.C.
54 E. Hemmerle, Westinghouse Electric Corp. , Pittsburgh, Pa.
55 J. C. Gallimore, WANL, NRDS, Jackass Flats, Nevada
56 Perry Davidson, WANL, NRDS, Jackass Flats, Nevada
57 V. M. Milligan, REECo, Mercury, Nevada
58 C. S. Maupin, REECo, Las Vegas, Nevada
59 J. A. Mohrbacher, Pan American, NRDS, Jackass Flats, Nevada
60 N. E. Erickson, Aerojet General Corp. , Jackass Flats, Nevada
61 H. G. Simens, Aerojet General Corp., Jackass Flats, Nevada
------- |