r
fa
() R P / R-H) 7 J S
IODINH-129 IN THK KNYIRONMKNT
AROUND A NUCI.KAR FUEL
R K P ROC K S SI NG PLANT
1
U. S. KN'VIkf >V\1! VIAL PKOTI -'(." I K )\
')ffi;f of RadiatiY.n Programs
-------
IODINE-129 IN THE ENVIRONMENT
AROUND A NUCLEAR FUEL
REPROCESSING PLANT
\
Paul J. Magno, Thomas C. Reavey, and John C. Apidianakis
October 1972
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Radiation Programs
Field Operations Division
Washington,D.C. 20460
-------
FOREWORD
The Office of Radiation Programs carries out a national program
designed to evaluate the exposure of man to ionizing and nonionizing
radiation, and to promote development of controls necessary to protect
the public health and safety and assure environmental quality.
Within the Office of Radiation Programs, the Field Operations
Division conducts programs relating to sources and levels of environ-
mental radioactivity and the resulting population radiation dose.
Reports of the findings are published in the monthly publication, Radi-
ation Data and Reports, appropriate scientific journals, and Division
technical reports.
The technical reports of the Field Operations Division allow
comprehensive and rapid publishing of the results of intramural and
contract projects. The reports are distributed to State and local
radiological health programs, Office of Radiation Programs technical
and advisory committees, universities, libraries and information serv-
ices, industry, hospitals, laboratories, schools, the press, and other
interested groups and individuals. These reports are also included in
the collections of the Library of Congress and the National Technical
Information Service.
Readers of these reports are encouraged to inform the Office of
Radiation Programs of any omissions or errors. Comments or requests
for further information are also invited.
W. D. Rowe
Deputy Assistant Administrator
for Radiation Programs
111
-------
PREFACE
The Office of Radiation Programs of the Environmental Protection
Agency, in cooperation with the New York State Department of Environ-
mental Conservation, Nuclear Fuel Services, Inc., and the Atomic Energy
Commission, have, over the past several years, conducted studies at the
Nuclear Fuel Services, the nation's first commercial nuclear fuel re-
processing plant. The overall purpose of these studies is to determine
the requirements of an environmental surveillance program for fuel re-
processing plants. Specific study objectives included (a) characteri-
zation of both the gaseous and liquid waste effluents from the plant,
(b) measurement of the environmental concentrations of the discharged
radionuclides, and (c) delineation of the critical exposure pathways
and estimation of the radiation doses to the population living near the
plant. The initial results of this study were published in a series of
four reports:
(1) BRH/NERHL 70-1
(2) BRH/NERHL 70-2
(3) BRH/NERHL 70-3
(4) BRH/NERHL 70-4
An Estimate of Radiation Doses Received by
Individuals Living in the Vioinity of a
Nuclear Reprocessing Plant
Liquid Waste Effluents from a Nuclear Fuel
Reprocessing Plant
An Investigation of Airborne Radioactive
Effluent from an Operating Nuclear Fuel
Reprocessing Plant
Q C
Calibration and Initial Field Testing K
Detectors for Environmental Monitoring
The results of this initial phase of the study indicated that
additional information was required to better characterize the critical
dose pathways and provide more accurate information for dose estimates.
The environmental distribution of discharged iodine-129 was one of the
subjects requiring further information. This report presents the re-
sults of followup studies on the iodine-129 discharges from Nuclear Fuel
Services and on the concentrations of this radionuclide in the environ-
ment around the plant.
Charles L. Weaver
Director
Field Operations Division
-------
ACKNOWLEDGMENT
The assistance and cooperation of the following individuals in
planning and carrying out this study is gratefully acknowledged.
John Russell
Office of Radiation Programs
Environmental Protection Agency
Floyd Gal pin
Office of Radiation Programs
Environmental Protection Agency
Charles Weaver
Office of Eadiation Programs
Environmental Protection Agency
Thomas Cashman
Bureau of Radiological Pollution Control
New lork State Department of Environmental Conservation
Kurt Anderson
Bureau of Radiological Pollution Control
flew York State Department of Environmental Conservation
Robert Wozniak
Bureau of Radiological Pollution Control
New York State Department of Environmental Conservation
Edward North
Nuclear Fuel Services
Terry Wenstrand
Nuclear Fuel Services
The authors wish to acknowledge the contribution of Paul B. Hahn
in evaluating, testing, and establishing the procedures described for
the "Determination of Iodine-129 by Liquid Scintillation" and the
"Volumetric Determination of Stable Iodine."
-------
TABLE OF CONTENTS
Page
FORWARD ill
PREFACE v
ACKNOWLEDGMENT vi
ABSTRACT ix
INTRODUCTION 1
SAMPLE COLLECTION 3
Terrestrial environment 3
Aqueous environment 3
Background 5
ANALYTICAL METHODOLOGY 6
Summary of activation analysis procedure 6
RESULTS AND DISCUSSION 7
Terrestrial environment 7
Aqueous environment 11
Background 11
IODINE-129 DISCHARGES FROM NUCLEAR FUEL SERVICES 11
SUMMARY AND CONCLUSIONS 13
RECOMMENDATIONS 14
ADDENDUM 15
REFERENCES 16
APPENDICES
I. Procedures for the analyses of iodine-129 and iodine-127
in environmental samples 17
II. Determination of iodine-129 by liquid scintillation
counting 21
III. Volumetric determination of stable iodine 23
VII
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Page
FIGURE
1. Sampling locations near Nuclear Fuel Services.
TABLES
1. Location of sample collection sites 5
2. Iodine-129 and stable iodine in small animal thyroids col-
lected in the vicinity of Nuclear Fuel Services 8
3. Iodine-129 and stable iodine in bovine thyroids and tissues
collected in the vicinity of Nuclear Fuel Services 9
4. Iodine-129 and stable iodine in bovine thyroids collected
in Bos ton, Mass 10
5. Average iodine-129 specific activities at various distances
from Nuclear Fuel Services 10
6. Iodine-129 and stable iodine in algae and fish from the
Buttermilk and Cattaraugus Creeks 12
7. Iodine-129 concentrations in milk collected from farms
located in the vicinity of Nuclear Fuel Services 15
Vlll
-------
ABSTRACT
The specific activity of iodine-129, i.e., the ratio of the
activity of iodine-129 to the weight of stable iodine, was measured in
the environment around the Nuclear Fuel Services' reprocessing plant,
West Valley, N.Y., during the summer of 1971. These measurements showed
that the discharges of iodine-129 from Nuclear Fuel Services produced
specific activities as high as 0.62 yCi/g of iodine in the aqueous en-
vironment and 0.28 yCi/g of iodine in the terrestrial environment around
the plant. These values are about 101* times greater than background
levels.
The average specific activity of iodine-129 in the environment
around the plant was 0.1 yCi/g of iodine or 7 percent of the specific
activity which if present in the human thyroid would result in the indi-
vidual dose limit specified by the Federal Radiation Council.
The results of this study indicated a need for control of iodine-129
discharges from nuclear fuel reprocessing plants and surveillance pro-
grams to evaluate the environmental buildup of this radionuclide. Ana-
lytical procedures for determinatipn of iodine-129 by neutron activation
analysis and by liquid scintillation counting are included.
IX
-------
Mr. Paul J. Magno, Mr. Thomas C. Reavey, and Mr. John C.
Apidianakis were formerly at the Northeastern Radiological
Health Laboratory, Environmental Protection Agency, 109 Holton
St., Winchester, Mass. 01890. Mr. Magno is now with the Tech-
nology Assessment Division, EPA, 5600 Fishers Lane, Rockville,
Md. 20852. Mr. Reavey is with EPA at the Eastern Environmen-
tal Radiation Laboratory, P.O. Box 61, Montgomery, Ala. 36101.
Mr. Apidianakis is still at NERHL with the Bureau of Radio-
logical Health.
-------
IODINE-129 IN THE ENVIRONMENT AROUND
A NUCLEAR FUEL REPROCESSING PLANT
INTRODUCTION
Discharges of iodine-129 to the environment from the operations
of the nuclear industry are of particular interest because of the 17
million year half-life of iodine-129 and its ability to enter into the
food chain and subsequently concentrate in the human thyroid. Because
of its long half-life, discharged iodine-129 becomes a permanent con-
taminant in the environment and as a result represents a potential
long-term public health problem which must be studied to determine its
magnitude. Such a study, ultimately conducted by the U.S. Environ-
mental Protection Agency, was begun in 1969 to determine the amount of
iodine-129 discharged to the environment from the Nuclear Fuel Services'
reprocessing plant at West Valley, N.Y. , and to investigate the distri-
bution of iodine-129 near the plant. Iodine discharge estimates for
the plant's operation period of about 5 years and measurements of
environmental samples taken near the plant environs during the summer
of 1971 form the basis for this report.
During normal operations of nuclear power stations, negligible
amounts of iodine-129 are discharged to the environment (1). During
subsequent chemical processing of spent fuel at a fuel reprocessing
plant, a much greater potential.exists for discharge to the environ-
ment of a portion of the iodine-129 present in the fuel elements.
Iodine removal systems are installed in the off-gas cleaning systems
at fuel reprocessing plants principally to remove iodine-131 which is
still present in fuel cooled for 150 days, the current design cooling
period.
The iodine removal system installed at Nuclear Fuel Services, the
nation's first commercial nuclear fuel reprocessing plant, consisted of
a chemical scrubber followed by silver reactors. The chemical scrubber
is a 20-inch diameter by 10-foot packed column in which the dissolver
off-gases are scrubbed with a stream of mercurous and mercuric nitrate
solution.1 The silver reactor, consisting of ceramic Berl Saddles
coated with silver nitrate (2), never achieved the design conditions
and were largely ineffective for iodine absorption.1
Since all of the fuel processed had cooled for more than a year,
no measurable iodine-131 was discharged to the environment (3). How-
ever, an Environmental Protection Agency study to characterize
•Personal communication from E. D. North, Director Technical
Administration, Nuclear Fuel Services, Inc.
-------
radioactive waste effluents from Nuclear Fuel Services (4) showed that
significant quantities of iodine-129 were discharged to the environ-
ment via the stack during fuel dissolution. Data from the State of
New York Department of Environmental Conservation also showed detect-
able concentrations of iodine-129 in deer thyroids collected around
the Nuclear Fuel Services plant (5). These data indicated that a
detailed study of the concentrations of iodine-129 in the environment
around the Nuclear Fuel Services plant was desirable to determine the
effects of the iodine-129 discharges on the environment.
Russell and Hahn (1), in an evaluation of the public health
significance of iodine-129 from the nuclear power industry, suggested
that one of the ways to evaluate the health significance of iodine-129
in the environment is to determine the specific activity of iodine-129,
i.e., the ratio of activity of iodine-129 to the weight of stable
iodine. This value is then compared to a limiting specific activity.
For evaluation of exposures to the general population, Russell and
Hahn (1) suggested a limiting specific activity of 1.4 uCi/g iodine as
that specific activity of iodine-129 which, if present in a human thy-
roid, would result in a dose rate of 500 mrem/yr., the recommended
Federal Radiation Council (FRC) dose limit for an individual in an
exposed population (6).
To evaluate the significance of the iodine-129 discharges from
Nuclear Fuel Services, the Environmental Protection Agency carried out
measurements of the iodine-129 and stable iodine (iodine-127) concen-
trations in the environment around the facility. The objectives of
this study were:
(a) to measure the specific activity of iodine-129 in the environ-
ment resulting from both gaseous and liquid discharges,
(b) to compare these specific activities with the limiting spe-
cific activity as suggested by Russell and Hahn (1), and
(c) to compare the specific activities around the plant with
background specific activities to determine the extent of the change
due to plant operations.
The environmental concentrations of iodine-129 which are presented
in this report resulted from operations of the Nuclear Fuel Services
plant when the iodine removal system consisted essentially of only a
chemical scrubber. Nuclear Fuel Services is installing an improved
iodine removal system consisting of a caustic scrubber followed by a
highly efficient silver zeolite absorber.1 Similar systems will be
installed at the Midwest Fuel Recovery Plant and the Barnwell Nuclear
Fuel Plant. These systems are expected to have a much greater iodine
removal efficiency than the system first installed at Nuclear Fuel
Services.
-------
SAMPLE COLLECTION
Figure 1 shows the locations where samples were collected for
this study; table 1 describes the sample locations and lists the dis-
tances of the locations from the plant.
Terrestrial environment
To evaluate the effect of stack discharges of iodine-129 on the
environment, thyroid samples were collected from animals whose grazing
habits or other limitations (fences, etc.) would restrict the intake
of iodine-129 to the airborne pathway. Bovine thyroids2 are a useful
sample for this purpose since these animals graze in known restricted
areas. Thyroids from woodchucks and rabbits are also useful since
these animals usually graze within limited areas. Animals such as
deer whose grazing habits and range include: (a) the area within the
high exclusion fence and (b) the stream system into which the liquid
waste is discharged were not used in this study. Data from the State
of New York Department of Environmental Conservation (5) had shown con-
centrations of iodine-129 in deer thyroids ranging up to 4 x 103 pCi/g
of tissue. However, it was difficult to evaluate these data since the
pathway through which the animal obtained the iodine-129 could not be
established.
During the summer of 1971 the following samples were obtained for
this study:
(1) Thyroids from woodchucks or rabbits collected at sample lo-
cations. 12, 13, 14, 15, and 17-
(2) Bovine thyroids collected at a slaughterhouse from animals
which had grazed at sample locations 16, 17, 19, and 20.
(3) Bovine tissues (mistakenly submitted as thyroids) collected
at a slaughterhouse from animals which had grazed at sample
locations 11, 18, and 21.
Aqueous environment
To evaluate the effect of liquid discharges, samples of algae and
fish were collected during June 1971 from the Buttermilk and Catta-
raugus Creeks, the aqueous environment into which the liquid waste
2Although milk represents the pathway to man, bovine thyroids
were used for this study because the thyroid is easier to analyze and
permits a more sensitive measurement of the specific activity of
iodine-129. For example, a 10-gram sample of bovine thyroid contained
5-10 mg of stable iodine whereas a 1-liter sample of milk would usually
contain <0.1 mg of stable iodine.
^Personal communication from C. F. Cisar, Twinbrook Research
Laboratory, Environmental Protection Agency (1972).
-------
Figure 1. Sampling locations near Nuclear Fuel Services
-------
Table 1. Location of sample collection sites
Location
Dutch Hill Road and
Schwartz Road and
"Rnn I" *a 9 1 Q A olrFrv-*-^
L»uunuy jxoao. j
-------
ANALYTICAL METHODOLOGY
Because of the low specific activity of iodine-129 (1.7 x W~** Ci/g) ,
activation analysis is a more sensitive technique for measuring this
radionuclide in environmental samples than conventional counting tech-
niques. Edwards (8) and Keisch et al. (9) have discussed the measure-
ment of low concentrations of iodine-129 in environmental samples by
neutron activation.
All of the iodine-129 concentrations and some of the iodine-127
concentrations (except those of the bovine thyroids) presented in this
report were determined using a neutron activation procedure.
In this procedure, the iodine-129 and iodine-127 were neutron-
activated to iodine-130 and iodine-128 respectively and the resultant
activities measured by conventional gamma spectrometry. This pro-
cedure is summarized below and described in detail in appendix I.
When the stable iodine content of a sample exceeded 1 mg (this
applied only to the bovine thyroids) a volumetric method of measurement
was used. This procedure is described in appendix III. When the
iodine-129 content of a sample exceeds 10 pCi, a liquid scintillation
counting procedure may be used. A procedure that has been tested for
this purpose at this laboratory is presented in appendix II.
Summary of activation analysis procedure
The sample is solubilized by fusion with sodium hydroxide.
Iodine-131 tracer is added to determine yield. The iodine is separated
from the sample by a series of solvent extraction steps with carbon
tetrachloride and toluene. The iodine is then irradiated in an am-
monium sulfite solution for 1 hour in a thermal neutron flux of
2 x 1013 n/cm2 per sec. For this study the pneumatic rabbit facility
at the Massachusetts Institute of Technology Research Reactor was used.
Following irradiation, additional chemical purification of the iodine
is accomplished by extraction with carbon tetrachloride and the puri-
fied sample is counted three times by conventional gamma spectrometry.
The first count at about 1 hour after irradiation is used to determine
the iodine-127; the second count 6 to 12 hours after irradiation is
used to determine the iodine-129; and the third count 5 days after
irradiation is used to measure the iodine-131 tracer and to correct
for the yield.
The activation analysis procedure was designed to meet the ob-
jectives of this study. For more sensitive measurements of iodine-129
(and more accurate measurement of the background levels of this radio-
nuclide) longer irradiation times and more specialized counting
techniques must be used.
-------
RESULTS AND DISCUSSION
Terrestrial environment
The results of the measurements of iodine-129 and stable iodine in
small animal thyroids collected at distances from 0.2 to 3 miles from
the Nuclear Fuel Services stack are presented in table 2. Table 3
presents the result of the measurements made on bovine thyroids and
tissues collected from animals grazing at distances 1 to 10 miles from
the point of discharge. Table 4 presents the results of measurements
on bovine thyroids collected from Boston, Mass., which, for the pur-
poses of this study, serve as background control samples.
The 2-sigma counting error associated with the measurements of
iodine-127 and iodine-129 were all less than 5 percent unless otherwise
noted. The overall analytical error associated with these measure-
ments have not yet been fully evaluated. Preliminary tests indicated
a precision of ± 5 to 10 percent.
The highest iodine-129 specific activity measured in small animal
thyroids was 2.4 x 10 1 yCi/g iodine and this occurred in a woodchuck
collected 0.2 miles from the plant. The highest specific activity
measured in a bovine thyroid was 2.8 x 10"1 yCi/g of iodine and this
was collected from a cow which had grazed approximately 1 mile from the
plant. In general the highest iodine-129 specific activities were
measured in samples collected closest to the plant and the specific
activity decreased with the distance from the plant. The average
iodine-129 specific activities in samples collected at various dis-
tances from the plant are presented in table 5. Although only a rela-
tively small number of samples have been analyzed and a wide spread in
the data has been observed, (particularly for the samples collected
close to the plant), these data support the observation that the
iodine-129 specific activity decreased with distance from the plant.
The data in table 5 show that at 5 to 6 miles from the plant the
iodine-129 specific activity was 100 times greater than the background
level and that even at a distance of 10 miles from the plant the
iodine-129 specific activity was ten times the background level.
The average iodine-129 specific activity in samples collected 0 to
3 miles from the plant was 1.0 x 10"1 yCi/g of iodine or 7 percent of
the limiting specific activity discussed by Russell and Hahn (1). The
specific activity data from these samples cannot be used directly to
evaluate the radiation exposure from this radionuclide to the popula-
tion living in the vicinity of the plant, since it is not known what
fraction of the stable iodine intake for this population is of local
origin. However, these data do indicate (although the plant has been
operating at less than 50 percent capacity for only about 5 years) that
the iodine-129 specific activities in the environment around the plant
-------
00
Table 2. Iodine-129 and stable iodine in small animal thyroids
collected in the vicinity of Nuclear Fuel Services
Tvnp c\f
i y pc u i
sample
Woodchuck
P o V> V. -i t-
Woodchuck
P rtUV, -1 t-
Wo od chuck
Woodchuck
Woodchuck
Woodchuck
Datp
collected
4/71
c 771
-> 1 1 L
6/71
A /71
t / / J-
5/71
5/71
5/71
4/71
Pnl 1 prl" "i nn
site
12
1 A
14
1 7
±/
17
13
15
14
Distance
and
Hi v*0p"f~ inn
from
plant stack
(miles)
0.2 NW
1Q -\TTJ
1.8 NW
19 MT7
1.2 NE
1.0 NW
2.8 WNW
1.8 NW
yg_iodine
g tissue
(wet wt. )
9.4 x 102
c: q __ i f)2
2.0 x 102
69 v i n2
5.1 x 102
4.5 x 102
9.9 x 102
2.9 x 102
yg 129I
g tissue
(wet wt. )
1.3
cr £ __ -\ f\— 1
1.5 x KT1
o o „ i n~ 1
J . i. X J.U
2.4 x 10'1
1.8 x 10"1
6.0 x 10~2
1.3 x 10~2
yg 129I
g iodine
1.4 x 103
i n v T n3
7.5 x 102
59 „ i r>2
. Z X J-U
4.7 x 102
4.0 x 102
6.1 x 101
4.5 x 101
yCi 129I
g iodine
2.4 x 10" 1
T 7 „ i r\~ 1
-L . / X -LU
1.3 x 10"1
9n -
-------
Table 3. Iodine-129 and stable iodine in bovine thyroids and tissues
collected in the vicinity of Nuclear Fuel Services
Type of
sample
Thyroid
Thyroid
Tissue
Date
collected
9/71
9/71
9/71
9/71
9/71
9/71
9/71
6/70
8/71
6/70
Collection
site
17
16
17
19
19
19
20
18
11
21
Distance
and
di rection
from
plant stack
(miles)
1.2 NE
2.1 W
1.2 NE
6.0 NNW
6.0 NNW
6.0 NNW
5.0 NNE
2.5 NNE
1.6 S
10.0 NE
yg iodine
g tissue
(wet wt.)
6.8 x 102
4.4 x 102
9.3 x 102
1.1 x 103
8.5 x 102
6.9 x 102
2.1 x 103
1.1
1.4
4.6 x I0l
yg 129I
g tissue
(wet wt. )
1.1
2.4 x 10" !
3.5 x 10"2
3.9 x 10'2
2.2 x 10~2
2.2 x ID" 2
2.2 x 10" 2
a6.3 x 10-4
a1.2 x 10-4
a1.0 x 10-4
yg 129I
g iodine
1.6 x 103
5.5 x 102
3.8 x 101
3.5 x 101
2.6 x 101
3.2 x 101
1.0 x 101
5.7 x 102
8.6 x 101
2.2
yCi 129I
g iodine
2.8 x 10"1
9.5 x 10~2
6.6 x 10~3
6.1 x 10~3
4.5 x 10~3
5.5 x 10~ 3
1.7 x 10~3
9.9 x 10~2
1.5 x 10~2
3.8 x HT4
a2o counting error equal to ~0.5 x 10 ** yg/g tissue.
-------
Table 4. Iodine-129 and stable iodine in bovine thyroids
collected in Boston, Mass.
Sample
number
i
2
3
A
5
6
n^ +• r\
uate
collected
i n /7n
10/70
10/70
ft /71
8/71
8/71
pg iodine
g tissue
(wet wt. )
9 A -y 1 f)2
3.0 x 102
4.6 x 102
A n ,, i r\2
8.0 x 102
5.7 x 102
yg 129I
g tissue
(wet wt.)
i -v i n~ ^
b
-------
have increased to levels many orders of magnitude greater than
background levels and to a significant fraction of the limiting spe-
cific activity.
Aqueous environment
The results of the measurements made on algae and fish samples
collected from the Buttermilk and Cattaraugus Creeks are presented in
table 6. The iodine-129 specific activity in the samples collected
from Buttermilk Creek averaged 5.3 x 10"1 yCi/g iodine and this was a
factor of about 10^ greater than the specific activity of 5 x 10~5
iodine measured in the background samples. The iodine-129 specific
activity in samples from the Cattaraugus Creek averaged 5.8 x 10~2 yCi/g
iodine or a factor of about 103 greater than background.
The algae and fish samples from the same locations contained
similar specific activities of iodine-129 indicating that an approxi-
mate state of equilibrium had been established for iodine-129 and stable
iodine in the stream system. The iodine-129 specific activity in
samples from Buttermilk Creek was about ten times greater than that of
samples taken from Cattaraugus Creek. This factor of ten is about equal
to the dilution factor obtained when Buttermilk Creek empties into
Cattaraugus Creek.
The iodine-129 specific activity in the Buttermilk Creek was 40
percent of the limiting specific activity of 1.4 pCi/g iodine as defined
by Russell and Hahn (1).
Background
One of the objectives of this study was to determine if the
specific activity of iodine-129 in the environment around Nuclear Fuel
Services was significantly different from background levels. The spe-
cific activity of iodine-129 in the Nuclear Fuel Services environment
was 103 to 101* times greater than background levels of iodine-129 as
measured in thyroids collected in Boston, Mass., which, for the pur-
poses of this report, were considered to be adequate. However, since
these background data were derived from only a few thyroid samples from
one geographical location and since no recent data on iodine-129 in the
environment are available in the literature, the limitations of the
background levels of iodine-129 are recognized. Additional studies are
therefore needed to establish accurately the background concentrations
of iodine-129 in the environment, particularly in the environment of
future nuclear fuel reprocessing plants prior to operation.
IODINE-129 DISCHARGES FROM NUCLEAR FUEL SERVICES
From April 1966 to July 1971, about 600 metric tonnes of uranium
were processed by Nuclear Fuel Services with a total burnup of 4 x 106
megawatt days. The amount of iodine-129 in this fuel is estimated to
have been approximately 4.4 curies (2).
11
-------
Table 6. Iodine-129 and stable iodine in algae and fish
from the Buttermilk and Cattaraugus Creeks
media
Algae — —
Sucker
Trout
na+o
collected
(L I Q /71
o/ y / /i
(LI Q /7T
o/ y / / L
(LI Q IT\
o / y/ /i
6/10/71
fi /I fl /71
6/10/71
site
e:
7
5
7
8
Location
Buttermilk
Cattaraugus
Distance
plant9
(mi les)
0 O
/. 1
61
3.3
/. i
6.1
yg iodine
g sample
(wet wt. )
i i
1 C\
1 1
4.6
A A
1.9
yo: 129I
g sample
(wet wt. )
0 Q „ 1 f\— 3
/. A _, 1 A~ 4
3Q _- Ifi""1*
1.2 x 10~2
i s •»• in~3
6,0 x 10"4
ug 129i
g iodine
3c „ n n 3
4n v T n2
3c „ i r\2
2.6 x 103
9 R v in2
3.2 x 102
yCi 129J
g iodine
61 v 1 ft— 1
61 v i n— 2
4.5 x 10-1
A R -v 1O— 2
5.5 x 10-2
Stream miles from point of discharge of liquid waste.
-------
The iodine-129 discharged to the aqueous environment from April
1966 to July 1971 is estimated to have been about 0.9 curie or 20 per-
cent of the total amount of iodine-129 in the fuel processed. This
estimate is based principally on iodine-129 discharge data6 reported by
Nuclear Fuel Services (3). A new low-level waste treatment facility
became operational in the summer of 1971. This treatment facility is
not expected to reduce the iodine-129 discharges significantly unless
additions are made to the facility for this purpose.
No data were available on stack discharges of iodine-129 for the
period April 1966 to January 1971. However, for the purposes of this
report, the stack discharges of iodine-129 for this period were roughly
estimated by the following method:
An activated charcoal trap used by Nuclear Fuel Services to sample
iodine stack discharges for the period April through June 1971 was
analyzed for iodine-129 by the Environmental Protection Agency. This
analysis and data based on the burnup of fuel processed during this
period, indicated that 25 percent of the iodine-129 present in the fuel
was discharged to the environment via the stack. This value is prob-
ably a minimum value, since the efficiency of the activated charcoal
for retaining iodine is unknown.7 If this value of at least 25 percent
was representative of the iodine-129 discharged via the stack during
the entire period of operation, then a minimum of 1.1 curies of
iodine-129 were discharged to the environment by this route for the
period April 1966 to July 1971.
SUMMARY AND CONCLUSIONS
During the first 5 years of operation of the Nuclear Fuel Services
plant, discharges of iodine-129 have resulted in specific activities of
this radionuclide as high as 6.1 x 10"1 yCi/g of iodine in the aqueous
environment and 2.8 x 10"1 yCi/g of iodine in the terrestrial environ-
ment around the plant. These values are a factor of about 10^ higher
than background levels. Even at a distance of 10 miles from the plant,
the iodine-129 specific activity was ten times the background.
The average specific activity in the terrestrial environment
around the plant perimeter was 1 x 10"1 yCi/g of iodine or 7 percent of
the limiting specific activity. Although the specific activity data
could not be used to estimate the radiation exposure to the population
living in the vicinity of the plant, it did indicate a rapid buildup of
iodine-129 in the plant environs, which requires careful consideration
and further evaluation.
6No liquid discharge data were available for April 1966 through
December 1966, and the discharge estimated for this period was based on
the amount of fuel processed.
7Personal communication from J. H. Keller, Idaho Nuclear Corpora-
tion (1971).
13
-------
Data on iodine-129 discharges from Nuclear Fuel Services indicate
that a large percentage of the iodine-129 present in the spent fuel
elements will be volatilized during fuel reprocessing. Most of this
liberated iodine-129 will be removed by the off-gas cleaning system.
For a 1,500 ton-per-year plant, as much as 800 pounds of iodine-129
per year could be retained by the off-gas cleaning system. Details are
not available on the method of disposal planned for the components of
the off-gas cleaning systems of fuel reprocessing plants. However,
procedures which would result in permanent storage of the iodine-129
present in these components would seem to be indicated.
The results of this study indicate a need for controlling
iodine-129 discharges from nuclear fuel reprocessing plants and sur-
veillance programs® to evaluate the environmental buildup of this radio-
nuclide. The recommendations presented below are directed toward these
areas.
RECOMMENDATIONS
(1) To keep the stack discharge of iodine-129 as low as
practicable, all nuclear fuel reprocessing plants
should be required to operate their iodine removal
system even when processing aged fuel in which the
iodine-131 content has decayed to a small quantity.9
(2) Environmental surveillance programs at nuclear fuel
reprocessing plants should include periodic measurements
of the specific activity of iodine-129 in the plant
environs.10
(3) Careful consideration should be given to the methods
used for the disposal of the scrubber solutions and ab-
sorbers used in iodine removal systems.
(4) A detailed research study of the behavior of iodine-129
in the Nuclear Fuel Services plant environmental eco-
system should be carried out. Information should also
be obtained on the stable iodine intake for the popu-
lation living in the vicinity of the plant to determine
what percentage of their total iodine intake is of local
origin. Measurements of iodine-129 in human thyroids
from individuals who had lived in the vicinity of the
plant would be desirable whenever possible. As a part
8Similar to those carried out by the New York State Department of
Environmental Conservation.
9This recommendation is in contrast to those of Bryant (10) and
Rodger (11) who have indicated that discharges of iodine-129 to the
environment will not be a serious problem for plants processing less
than 5 to 10 tonnes of fuel per day.
^Yearly measurements of iodine-129 and stable iodine in bovine
thyroids or in milk collected around the plant should provide the
required information.
14
-------
of this study, background specific activities of iodine-129
should also be established, both in the general environ-
ment and in the environs of fuel reprocessing plants prior
to facility operations.
ADDENDUM
Measurements of iodine-129 were made on a series of milk samples
collected by the New York State Department of Environmental Conserva-
tion during the spring of 1972 from farms located in the vicinity of
Nuclear Fuel Services. These measurements using activation analysis
were carried out in order to verify the detection of iodine-129 in milk
by the New York State Department of Environmental Conservation (12)
whose measurements were made using the liquid scintillation technique
(appendix II). The results of these measurements are presented in
table 7. These data showed detectable iodine-129 in all samples col-
lected. The iodine-129 concentrations ranged from 0.05 to 1.51
pCi/liter.
Table 7. Iodine-129 concentrations in milk
collected from farms located in the vicinity
of Nuclear Fuel Services
Date
collected
O / Q 1 / 7 9
-}/ J-L/ /z
LI L IT)
4/ f/ / i.
9 /9 Q /79
J/ Zo/ / Z
/. / o /TO
4/ J//Z
q /oi /79
J/ Jl/ /Z
0/90/70
J/ Zo/ / Z
A / L. IT)
*t / 4/ /Z
Q /9Q IT)
j//y/ / z
A / o / 7 9 _
4/ J//Z ~
3/30/72
/.If. IT)
H/ D/ /Z—
Distance
from
plant stack
(miles)
9 n
/ . u
1 C.
1 7
-L . /
9 f)
0 fl
c; n
7 0
c: n
s n
7.0
AlKonir \T V
Iodine-129
(pCi /liter)
i ^.i
-L . Jj-
i n/i
Q7
. o /
fin
o c:
on
. JU
1 Q
Ofi
.05
-------
REFERENCES
(1) Russell, J. L. and P- B. Hahn. Public Health Aspects of 1-129
from the Nuclear Power Industry. Radiol Health Data Rep 12:189-
194 (April 1971).
(2) Nuclear Fuel Services, Inc. Spent Fuel Reprocessing Plant (pre-
liminary safety report) Part B, U.S. Atomic Energy Commission
Docket 50201. Nuclear Fuel Services, Inc., P.O. Box 124, West
Valley, N.Y. (July 26, 1962).
(3) Nuclear Fuel Services, Inc., West Valley Reprocessing Plant.
Quarterly Reports for the Period April 1966 through June 1971.
Nuclear Fuel Services, Inc., P.O. Box 124, West Valley, N.Y.
(4) Cochran, J. A., D. G. Smith, P- J. Magno and B. Shleien. An In-
vestigation of Airborne Radioactive Effluent from an Operating
Nuclear Fuel Reprocessing Plant, BRH/NERHL 70-3. Bureau of Radio-
logical Health, Public Health Service, U.S. Department of Health,
Education, and Welfare, Rockville, Md. 20852 (July 1970).
(5) State of New York Department of Environmental Conservation. An-
nual Report of Environmental Radiation in New York State in 1970.
State of New York Department of Environmental Conservation, Albany,
N.Y. (June 1971).
(6) Federal Radiation Council. Background Materials for the Develop-
ment of Radiation Protection Standards, Report No. 2 (1961).
Superintendent of Documents, U.S. Government Printing Office,
Washington, D.C. 20402.
(7) Chavin, W. Thyroid Distribution and Function in the Goldfish
Carassius auratus. Experimental Zoology 133:259-279 (November
1956).
(8) Edwards, R. R. Iodine-129: Its Occurrence in Nature and its
Utility as a Tracer. Science 137:851 (1962).
(9) Keisch, B., R. C. Koch and A. S. Levine. Determination of Bio-
spheric Levels of 129I by Neutron Activation Analysis. Confer-
ence on Modern Trends in Activation Analysis, College Station, Tex.
(April 1965), pp. 284-290.
(10) Bryant, P. M. Derivation of Working Limits for Continuous Release
Rates of 129I to the Atmosphere. Health Physics 19:611-616 (1970).
(11) Rodger, W. A. and S. L. Reese. The Removal of Iodine from Re-
processing-Plant Effluents. Reactor Fuel Processing Technol 12:
173-180 (Spring 1969) .
(12) State of New York Department of Environmental Conservation, En-
vironmental Radiation Bulletin 72-1. State of New York Department
of Environmental Conservation, Albany, N.Y. (July 1972).
16
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APPENDIX I
PROCEDURES FOR THE ANALYSES OF IODINE-129 AND IODINE-127
IN ENVIRONMENTAL SAMPLES
The procedures described below have been specifically written for
the analysis of thyroid samples. These procedures are also equally
applicable to other environmental samples. However, if the sample size
exceeds 10 grams, then the "Sample Preparation" and "Iodine Extraction"
procedures would have to be scaled up appropriately.
When the iodine-129 content of a sample is known to exceed 5 to 10
pCi, then determination by liquid scintillation counting is recommended.
For smaller amounts of iodine-129, determination by activation analysis
is recommended. Likewise, when the stable iodine content of a sample
exceeds 1 mg then it may be determined by titrimetry; otherwise it can
be determined simultaneously with the iodine-129 by activation analysis.
SAMPLE PREPARATION
1. Cut the thyroid (5 to 10 grams) into small pieces and place in a
250-ml nickel crucible. If the sample is to be analyzed by neutron
activation, add about 1,000 dpm of carrier-free iodine-131 for
determination of the chemical recovery.
2. Add 10 ml of water, 30 grams of NaOH pellets and, carefully, 10 ml
of ethyl alcohol.
3. Heat gently on a hot plate, stirring as needed, to solubilize the
mass. Evaporate off the ethyl alcohol.
4. Place the crucible in a muffle furnace at 250° C. Raise the temper-
ature to 600° C. in increments of 100 degrees at 15 to 30 minute
intervals.
5. Remove the crucible from the muffle furnace and cool. Dissolve the
melt with water and transfer to an 800-ml beaker. Wash the cru-
cible with water.
IODINE EXTRACTION
1. Heat the solution from step 5 of the "Sample Preparation" procedure
to just below boiling on a hot plate. Add additional water if
necessary (volume should be about 400 ml). Slowly pass chlorine
gas through the solution for about 30 seconds.
2. Cool the solution. Acidify using concentrated nitric acid (pH < 1)
and transfer to a 1,000-ml separatory funnel.
3. Add 50 ml of carbon tetrachloride and 10 ml of 1 M hydroxylamine
hydrochloride. Shake for 2 minutes to extract the iodine into the
organic phase. Draw off the organic layer into a 250-ml separatory
funnel.
17
-------
4. Add 25 ml of carbon tetrachloride and 5 ml of 1 M_hydroxylamine
hydrochloride to the first separatory funnel and shake for 2 min-
utes. Combine the organic phases. Discard the aqueous phase.
5. Add 25 ml water and 10 drops of 1 M sodium sulfite to the sepa-
ratory funnel containing the carbon tetrachloride. Shake for 1 to
2 minutes. Discard the organic phase.
6. Add 20 ml of toluene, 1 ml of 1 M nitric acid, and 10 drops of
1 M sodium nitrite to the separatory funnel. Shake for 1 to 2
minutes. Discard the aqueous phase.
7- Add 10 ml of water and 10 drops of 1 M, sodium sulfite to the sepa-
ratory funnel and shake for 1 to 2 minutes. Transfer the aqueous
phase to a 60-ml separatory funnel. Discard the organic phase.
8. Add exactly 10 ml of toluene, 1 ml of 1 M nitric acid and 10 drops
of sodium nitrite to the separatory funnel and shake for 2 minutes.
Discard the aqueous phase.
9. Add 10 ml of 0.01 M nitric acid to the separatory funnel and shake
for 30 seconds. Discard the aqueous phase.
10. Repeat step 9.
11. If the sample is known to contain more than 5 to 10 pCi of
iodine-129, proceed with the "Determination of Iodine-129 by Liquid
Scintillation Counting" (appendix II); otherwise proceed with the
"Determination of Iodine-129 by Neutron Activation." If there is
a distinct pink color to the toluene layer, use the procedure for
the "Volumetric Determination of Stable Iodine" (appendix III);
otherwise determine the stable iodine (iodine-127) simultaneously
with the iodine-129 by neutron activation.
DETERMINATION OF IODINE-129 AND IODINE-127 BY NEUTRON ACTIVATION
1. Take a 5 to 10 ml aliquot of the toluene layer from step 10 of the
"Iodine Extraction" procedure and place this aliquot in a 60-ml
separatory funnel.
2. Add 4 ml of 1 M ammonium sulfite to the separatory funnel. Shake
for 2 minutes and transfer the aqueous phase to a 10-ml volumetric
flask.
3. Repeat step 2, combining the aqueous portions in the volumetric
flask and dilute to volume with 1 M^ ammonium sulfite. Transfer
5 ml of this solution to a polyethylene irradiation vial and heat
seal.
4. Prepare standards of iodine-127 and iodine-129 as follows: Pipet
exactly 5 ml of a stock solution containing a known amount of
iodine-127 (10 yg/ml) in 1 M[ ammonium sulfite into a polyethylene
vial and heat seal. Similarly, pipet exactly 5 ml of a stock
solution containing a known amount of iodine-129 (0.01 yg/ml) in
1 M_ammonium sulfite into another polyethylene vial and heat seal.
5. Irradiate the vials containing the samples and the standards in a
constant neutron flux of about 2 x lO1^ n/cm2-sec. for 60 minutes.
Record the exact time of removal from the flux. Allow the
18
-------
radioactivity in the vials to decay for at least 10 minutes.1
6. Cut open a vial carefully and transfer the solution (pipet exactly
4 ml of the standard solutions) to a 60-ml separatory funnel con-
taining 10 ml of water, 10 mg of iodine carrier (as potassium
iodide), and 20 ml of toluene.
7. Acidify with 6 ml of 1 M nitric acid. Add 2 ml of 1 M sodium
nitrite to completely oxidize the iodine to free iodine. Shake
for about 2 minutes. Discard the aqueous phase.
8. Wash the organic phase three times, shaking for 30 seconds with
10 to 15 ml of 0.01 M nitric acid each time. Discard washings.
9. Add 15 ml of 1 H ammonium sulfite. Shake for 1 minute. Transfer
the aqueous portion to a gamma counting container.
10. Add 15 ml of 1 M ammonium sulfite to the separatory funnel con-
taining the toluene and shake for 1 minute. Combine the aqueous
portion with the aqueous portion from step 9 and adjust the volume
to a predetermined geometry for gamma counting.
11. Count the sample gamma spectrometrically three times at the
following intervals:
(a) immediately after chemical separation for the measurement of
iodine-128;
(b) 6 to 12 hours 'after irradiation for the measurement of
iodine-130; and
(c) 5 days after irradiation for the measurement of iodine-131 to
determine chemical recovery.
CALCULATIONS
'»! or 1"! Mg/gra. - ^ (A - f)
A = Net cpm of iodine-128 or iodine-130 in the sample as deter-
mined from the gamma count data and corrected for decay to
time of removal from the neutron flux (Note 1)-
B = Net cpm of iodine-128 or iodine-130 as determined from the
gamma count data of a reagent blank and corrected for decay to
time of removal from the neutron flux.
C = Net cpm of 128I/yg 127I or net cpm of 130I/yg 129I at the time
of removal from the neutron flux as determined from the gamma
count data of the standards.
D = Overall chemical recovery of iodine in the sample (Note 2).
This value includes the correction for the aliquot taken for
irradiation.
E = Weight of the sample in grams.
F = Overall chemical recovery of iodine in the blank (Note 2).
This value includes the correction for the aliquot taken for
irradiation.
practice 30 to 60 minutes elapsed between the end of the
irradiation and the beginning of the postirradiation chemistry.
19
-------
Note 1: The net cpm of iodine-128 and iodine-130 are determined by
measuring the 0.44 MeV and 0.53 MeV photopeaks respectively
using a method of simultaneous equations similar to that de-
scribed by Hagee.2 For low-count rates spectral interferences
from iodine-131 and sodium-24 may also have to be considered.
Note 2: The chemical recovery is determined as follows:
Net cpm 131I in sample or blank
_
_ _
Net cpm 13ll in tracer added to sample or blank
The net cpm of iodine-131 is determined from the measurement
of the 0.36 MeV photopeak as described in Note 1.
2Hagee, G. A., G. J. Karches and A. S. Goldin. Determination of
131I} 137CSj and 140Ba ln Fiuid Milk by Gamma Spectroscopy- Talanta
5:36 (1960).
20
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APPENDIX II
DETERMINATION OF IODINE-129 BY LIQUID SCINTILLATION COUNTING
1. Pipet exactly 4 ml of toluene from step 10 of the "Iodine
Extraction" procedure into a liquid scintillation counting vial.
Add 1 ml of 2-methyl-l-butene and 10 ml of scintillation solution
(Note 1).
2. Cap the vial and place it under a fluorescent light for about 2
hours to decolorize the iodine.
3. Count for iodine-129 in a liquid scintillation counter.
Note 1: The scintillation solution is prepared by dissolving 7 grams
of 2,5-diphenyloxazole (PPO) and 0.1 gram of l,4-bis-2
(5-phenyl-oxazolyl)-benzene (POPOP) in 1 liter of toluene.
CALCULATION
AB
pCi 129I/gram of sample =
2.22 CDE
A = Net cpm of iodine-129 in aliquot of sample counted.
B = Volume (ml) of toluene added in step 8 of "Iodine Extraction"
procedure (10 ml).
C = Counting efficiency of iodine-129 (cpm/dpm).
D = Volume (ml) of toluene taken for analysis (4 ml).
E = Weight of sample taken for analysis (grams).
21
-------
APPENDIX III
VOLUMETRIC DETERMINATION OF STABLE IODINE
1. Pipet a 4-ml aliquot of the toluene layer from step 10 of the
"Iodine Extraction" procedure, into a 60-ml separatory funnel. Add
about 20 ml of water and 5 ml of 1 M^ sodium sulfite dropwise to
completely reduce the iodine to iodide. Shake for about 2 minutes.
2. Collect the aqueous portion in a 125-ml Erlenmeyer flask.
3. Add another 20 ml of water to the organic phase, and 10 drops of
sodium sulfite. Shake for 2 minutes. Combine the aqueous phase
with the aqueous portion from step 2. Discard the organic phase.
4. Add about 5 ml of bromine-sodium acetate solution (Note 1) and heat
to boiling to insure complete oxidation of the iodide to the iodate.
5. Cool in an ice bath. Add formic acid (88 to 90 percent) dropwise
until the yellow color of the bromine disappears (Note 2).
6. Add about 3 ml of 10 percent potassium iodide solution, 10 ml of
1 M sulfuric acid, and about 5 drops of 1 percent starch solution.
7. Titrate the liberated iodine with a standardized 0.02 N_ sodium
thiosulfate solution (Note 3). Color change is from blue to color-
less at the endpoint.
Note 1: The bromine-sodium acetate reagent is prepared by dissolving
10.0 grams of sodium acetate trihydrate and 2 ml of bromine in
100 ml of glacial acetic acid.
Note 2: The solution must be cooled before the excess bromine is de-
stroyed with formic acid. If the solution is too warm, the
formic acid will also reduce some of the iodate giving low
results. It is also important that the solution be colorless
after the bromine is destroyed with formic acid.
Note 3: The 0.02 N_ thiosulfate solution is prepared as follows: Dis-
solve 2.5 grams of Na2S203-Sl^O, 0.2 grams Na2C03, and 3 drops
of chloroform in water and make up to 1 liter. Standardize by
titrating against a known amount of iodine to obtain a titer
in ml of thiosulfate solution per mg of iodine.
CALCULATION
mg of iodine/gram of sample =
A B
C D E
A = Volume (ml) of thiosulfate solution used to titrate sample.
B = Volume of toluene added in step 8 of "Iodine Extraction" pro-
cedure (10 ml).
C = Titer: ml of thiosulfate solution per mg of iodine.
D = Volume of toluene taken for stable iodine determination (4 ml)
E = Weight of sample taken for analysis (grams).
23
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THE ABSTRACT CARDS accompanying this report
are designed to facilitate information retrieval.
They provide suggested key words, bibliographic
information, and an abstract. The key word con-
cept of reference material filing is readily
adaptable to a variety of filing systems ranging
from manual-visual to electronic data processing.
The cards are furnished in triplicate to allow
for flexibility in their use.
r. \ OCX LHNMKNT I'RINTIKII Ol KICK 1973—546-310/90
-------
IODINE-129 IN THE ENVIRONMENT AROUND NUCLEAR FUEL
REPROCESSING PLANT, ORP/SID 72-5. P. J. Magno,
T. C. Reavey and J. D. Apitianakis „(November 1972)
ABSTRACT: The specific activity, of iodine-129, i.e.,
the ratio of the activity of iodine-129 to the weight
of stable iodine, was measured in the environment
around the Nuclear Fuel Services' reprocessing plant,
West Valley, N.Y. , during the summer of 1971. These
measurements showed'that the discharges of iodine-129
from Nuclear Fuel Services produced specific activi-
ties as high as 0.62 yCi/g of iodine in the aqueous
environment and 0.28 yCi/g of iodine in the terres-
trial environment around the plant. These values are
about 10^ times greater than background levels.
(over)
IODINE-129 IN THE ENVIRONMENT AROUND NUCLEAR FUEL
REPROCESSING PLANT, ORP/SID 72-5. P- J. Magno,
T. C. Reavey and J. D. Apitianakis (November 1972)
ABSTRACT: The specific activity of iodine-129, i.e.,
the ratio of the activity of iodine-129 to the weight
of stable iodine, was measured in the environment
around the Nuclear Fuel Services' reprocessing plant,
West Valley, N.Y., during the summer of 1971. These
measurements showed that the discharges of iodine-129
from Nuclear Fuel Services produced specific activi-
ties as high as 0.62 yCi/g of iodine in the aqueous
environment and 0.28 yCi/g of iodine in the terres-
trial environment around the plant. These values are
about 101* times greater than background levels.
(over)
IODINE-129 IN THE ENVIRONMENT AROUND NUCLEAR FUEL
REPROCESSING PLANT, ORP/SID 72-5. P. J. Magno,
T. C. Reavey and J. D. Apitianakis (November 1972)
ABSTRACT: The specific activity of iodine-129, i.e.,
the ratio of the activity of iodine-129 to the weight
of stable iodine, was measured in the environment
around the Nuclear Fuel Services' reprocessing plant,
West Valley, N.Y., during the summer of 1971. These
measurements showed that the discharges of iodine-129
from Nuclear Fuel Services produced specific activi-
ties as high as 0.62 yCi/g of iodine in the aqueous
environment and 0.28 yCi/g of iodine in the terres-
trial environment around the plant. These values are
about HP times greater than background levels.
(over)
-------
The average specific activity of iodine-129 in the
environment around the plant was 0.1 yCi/g of iodine
or 7 percent of the specific activity which if pres-
ent in the human thyroid would result in the individ-
ual dose limit specified by the Federal Radiation
Council.
The results of this study indicated a need for con-
trol of iodine-129 discharges from nuclear fuel re-
processing plants and surveillance programs to evalu-
ate the environmental buildup of this radionuclide.
Analytical procedures for determination of iodine-129
by neutron activation analysis and by liquid scintil-
lation counting are included.
KEY WORDS: Environment; iodine-129; New York State;
nuclear fuel reprocessing plants; thyroids.
The average specific activity of iodine-129 in the
environment around the plant was 0.1 uCi/g of iodine
or 7 percent of the specific activity which if pres-
ent in the human thyroid would result in the individ-
ual dose limit specified by the Federal Radiation
Council.
The results of this study indicated a need for con-
trol of iodine-129 discharges from nuclear fuel re-
processing plants and surveillance programs to evalu-
ate the environmental buildup of this radionuclide.
Analytical procedures for determination of iodine-129
by neutron activation analysis and by liquid scintil-
lation counting are included.
KEY WORDS: Environment; iodine-129; New York State;
nuclear fuel reprocessing plants; thyroids.
The average specific activity of iodine-129 in the
environment around the plant was 0.1 yCi/g of iodine
or 7 percent of the specific activity which if pres-
ent in the human thyroid would result in the individ-
ual dose limit specified by the Federal Radiation
Council.
The results of this study indicated a need for con-
trol of iodine-129 discharges from nuclear fuel re-
processing plants and surveillance programs to evalu-
ate the environmental buildup of this radionuclide.
Analytical procedures for determination of iodine-129
by neutron activation analysis and by liquid scintil-
lation counting are included.
KEY WORDS: Environment; iodine-129; New York State;
nuclear fuel reprocessing plants; thyroids.
------- |