United States
Environmental Protection
Agency
Office of Radiation Programs
(ANR-459)
EPA/520/1-89-025
September 1989
&EPA
An Evaluation of Techniques
for Ocean Disposal of Soils
Containing Naturally
Occurring Radionuclides
(FUSRAP Wastes)
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EPA 520/1-89-025
AN EVALUATION OF TECHNIQUES FOR OCEAN DISPOSAL
OF SOILS CONTAINING NATURALLY OCCURRING RADIONUCLIDES
(FUSRAP WASTES)
Mark Fuhrmann and Peter Colombo
NUCLEAR WASTE RESEARCH GROUP
DEPARTMENT OF NUCLEAR ENERGY
BROOKHAVEN NATIONAL LABORATORY
ASSOCIATED UNIVERSITIES, INC.
UPTON, LONG ISLAND, NEW YORK 11973
September 1989
This report was prepared as an account of work
sponsored by the United States Environmental Protection Agency
under Interagency Agreement No. 89930696-01-5
Project Officer
Robert S. Dyer
Analysis and Support Division
Office of Radiation Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
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FOREWORD
In 1972 the Congress enacted Public Law 92-532, the Marine
Protection, Research and Sanctuaries Act, which authorized the
Environmental Protection Agency (EPA) to regulate any future ocean
disposal of waste materials, including low-level radioactive wastes (LLW).
Thus, since 1974, the EPA Office of Radiation Programs (ORP) has
conducted studies to determine effects from previous U.S. ocean disposals
of LLW, and to develop criteria for regulating any future disposals.
In recent years the oceans have been considered as a disposal option
for soils, containing very low levels of naturally occurring radionuclides,
from the Department of Energy's (DOE) Formerly Utilized Sites Remedial
Action Program (FUSRAP). This report discusses and evaluates five
potential techniques or methods, as proposed by the DOE, for ocean
disposal of FUSRAP wastes.
The Agency invites all readers of this report to send comments or
suggestions to Mr. Martin P. Halper, Director, Analysis and Support
Division (ANR-461), Office of Radiation Programs, Environmental
Protection Agency, Washington, DC 20460.
Richard J. Guimond, Director
Office of Radiation Programs
iii
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SUMMARY
This report presents and discusses five alternatives (techniques) for
ocean disposal of soils, containing very low levels of naturally occurring
radionulcides, from the Department of Energy's (DOE) Formerly Utilized
Sites Remedial Action Program (FUSRAP). These five techniques include:
(1) disposal of unsolidified wastes in a closed barge; (2) disposal of
unsolidified wastes in closed containers; (3) disposal of solidified wastes in
a closed barge; (4) disposal of solidified wastes in closed containers; and,
(5) disposal of solidified wastes without containerization.
Each technique is evaluated with respect to how it conforms to
eleven waste package performance criteria for ocean disposal of LLW.
The criteria, proposed in 1988, and specifications are listed in Section 2 of
this report The results of evaluating techniques and criteria are
discussed in Section 4. Two of the five disposal techniques conform to all
of the draft packaging criteria, namely: disposal of solidified wastes in a
closed barge, and disposal of solidified wastes in closed containers.
The report further states that the waste package performance
criteria, proposed for ocean disposal of LLW, are actually inappropriate
for FUSRAP and other long-lived radionuclide wastes. Thus, it is
recommended that a new set of criteria should be developed for ocean
disposal of FUSRAP, and other wastes, where solidification or
containerization provides no reduction of long-term risk(s).
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TABLE OF CONTENTS
Page
FOREWORD iii
SUMMARY v
LIST OF TABLES ix
LIST OF FIGURES xi
1. INTRODUCTION AND BACKGROUND 1
1.1. Waste Characterization 4
2, PROPOSED WASTE PACKAGE PERFORMANCE CRITERIA
FOR OCEAN DISPOSAL OF LOW-LEVEL RADIOACTIVE WASTE 13
2.1 Assumptions 13
22 Waste Package Performance Criteria and Specifications 14
3. OCEAN DISPOSAL TECHNIQUES FOR FUSRAP WASTE 17
3.1 Unsolidified Waste in a Closed Barge 17
3.1.1 Description 17
3.1.2 Evaluation 18
3.2 Unsolidified Waste in Closed Containers 20
3.2.1 Description 20
3.2.2 Evaluation 20
33 Solidified Waste in a Closed Barge 22
33.1 Description 22
33.2 Evaluation 24
3.4 Solidified Waste in Closed Containers 24
3.4.1 Description 24
3.4.2 Evaluation 26
3.5 Solidified Waste without a Container 26
3.5.1 Description 26
3.5.2 Evaluation 26
4. RESULTS AND DISCUSSION 28
4.1 Summary of Results 28
4.2 Discussion 30
4.2.1 Containers 30
4.2.2 Solidification 31
4.23 Leaching 31
5. CONCLUSIONS 32
REFERENCES 34
vii
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LIST OF TABLES
Page
Table 1
Disposal/Stabilization Alternatives
for FUSRAP Waste
Table 2
Radioisotopes in FUSRAP Waste 8
Table 3
Mean Concentrations of Trace Metals
in Middlesex FUSRAP Waste 8
Table 4
Projected Quantities and Characteristics
of Wastes Collected by FUSRAP Activities
Table 5
Evaluation of Ocean Disposal of FUSRAP Waste
for Conformance with Proposed Waste
Package Performance Criteria 29
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LIST OF FIGURES
Page
Figure 1 Locations of FUSRAP Sites 2
Figure 2 The Uranium-238 Decay Series 7
Figure 3 The Thorium-232 Decay Series 7
Figure 4 Disposal of Unsolidified Waste In A Closed Barge 19
Figure 5 Disposal of Unsolidified Waste In Closed Containers 21
Figure 6 Disposal of Solidified Waste In A Closed Barge 23
Figure 7 Disposal of Solidified Waste In Closed Containers 25
Figure 8 Disposal of Solidified Waste Without A Container 27
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1. INTRODUCTION AND BACKGROUND
The Formerly Utilized Sites Remedial Action Program (FUSRAP) of the U.S.
Department of Energy (DOE) is a program to identify, characterize and remediate sites
that were used in the past for processing, research, development and storage of
uranium and thorium ores, concentrates and residues [1]. There are 29 sites requiring
remedial action in 12 states and one radiological surveillance site, as shown in Figure 1
[2]. The sites are locations that were used by the Manhattan Engineering District of
the former U.S. Atomic Energy Commission (AEC) from the early 1940's to the early
1960's. Estimated total volumes of FUSRAP waste are 1.2 x lO6 m3 [2].
A variety of options have been considered for disposal of FUSRAP waste. They
have been described by Gilbert, et al, [3] and are shown in Table 1. The ocean
disposal option presents several advantages in cases where on-site disposal is not
practicable. Long-term risks are minimized by this option since there is no need for
concern about on-site intruders or groundwater contamination. Moreover, long-term
institutional control and alternate land-use policy questions become moot The ocean
disposal option does, however, have the associated risk of food-chain contamination due
to the potential for dispersion of wastes, both during disposal operations and after
disposal on the seafloor. To minimize the potential for such food-chain contamination,
the International Atomic Energy Agency (IAEA) has recommended a minimum depth
of 4,000 m for ocean disposal of low-level radioactive waste (LLW) materials.
In 1986 the Environmental Protection Agency's (EPA) Office of Radiation
Programs (ORP) reported on two studies pertaining to ocean disposal of FUSRAP
wastes from the Middlesex, NJ, FUSRAP site [4, 5].
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N>
Ml ACIO/PUf BLO CANYON. LOS ALAMOS. NM
Ml ALBANY RESEARCH CENTER. ALBANY. Oil
Ml ASHLAND OIL II. TONAWANDA. NV
104 BAVO CANYON. LOS ALAMOS. NM
Mi CHUPADEMA MESA. WHITE SANDS
MISSILE HANOI. NM
Ml DUPONT Ir COMPANY. OEEPWATER. NJ
IM W R. CRACK * COMPANY. CURTIS BAY. MO
114 KEUEX/PIERPONT. JERSEY CITY. NJ
IM NIAGARA FALLS STOHAOf SITE (VICINITY
PROP, l LEWISTON. NV
Itt MALLINCKROOT. INC.. ST. LOUIS. MO
III MIDDLESEX LANDFILL. MIDDLESEX. NJ
IU MIDDLESEX SAMPLING PLANT.
MIDDLESEX. NJ
IM NATIONAL OUARO ARMORY. CNKAQO. a
ttl PALOS PARK FOREST PRESERVE. COOK
COUNTY, II
Ul SEAWAY INDUSTRIAL PARK. TONAWANDA. NV
W SHPACK LANDFILL. NORTON. MA
US UNIVERSAL CYCLOPS. AUQUIPPA. PA 13}
U? VINTRON, BEVERLY. MA US
US LINDE AIR PRODUCTS. TONAWANOA. NY US
IM UNIVERSITY OF CALIFORNIA. BERKELEY. CA 140
Ul UNIVERSITY Of CHICAGO. CHICAGO. IL 141
1« ASHLANO OH. CO. 42. TONAWANOA. NV 141
IM ST. LOUIS AIRPORT BIT! IVtONITY PROP.I. 1S3
ST. LOUIS. MO
WAVNE/PEOUANNOCK. NJ
MAYWOOO. NJ
COLONIE. NY
HAZELWOOOILATTV A VENUE I, MO
GENERAL MOTORS. ADRIAN. Ml
SEYMOUR SPECIALTY WIRE. SEYMOUR. CT
ST. LOUIS AIRPORT SITE. ST. LOUIS. MO
O REMEDIAL ACTION PLANNED
$ REMEDIAL ACTION PARTIALLY COMPLETED
REMEDIAL ACTION COMPLETED
RADIOLOGICAL MONITORING ONLY
Figure 1. Locations for Formerly Utilized Sites Remedial Action Program Sites
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Table 1. Disposal/Stabilization Alternatives 1 for FUSRAP Wastes
A. No Action
B. Onsite Containment
B.I. Containment without future disposal
B.La. Above-surface containment
B.l.b. Near-surface containment
B.2. Containment with monitored future disposal
B.2.a. Institutional controls only
B.2.b. In-situ stabilization
B.2.c. Above-surface containment
B.2.d. Near-surface containment
C. Offsite Containment
C.I. Containment without future disposal
C.l.a. Above-surface containment
C.l.b. Near-surface containment
C.l.c. Intermediate-depth containment
C.2. Containment with monitored future disposal
C.2.a. Above-surface containment
C.2.b. Construction use
C.2.C. Near-surface containment
C.2.b. Intermediate-depth containment
C3. Containment with unmonitored future disposal
C3.a. Containerized ocean disposal
C3.b. Land disposal in deep geological structures
D. Offsite Immediate Disposal
D.I. Ocean Disposal
D.2. Land Disposal
1 No action = site released for unrestricted use.
Institutional controls only = regulatory-controlled access/use only; no physical action.
In-situ stabilization = in place waste stabilization.
Above-surface containment = above ground emplacement in an engineered structure.
Near-surface containment = land disposal in/within upper 15-20 m of earth's surface.
Intermediate-depth containment = land disposal in/within 20-100 m of earth's surface.
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This report presents and discusses five proposed techniques for ocean disposal of
FUSRAP waste. Each technique is based on preventing waste dispersal during disposal
so that large quantities of the material will not remain in the water column. All five
techniques are evaluated with respect to proposed waste package performance criteria
for deepsea disposal of LLW [6].
1.1 Waste Characterization
Most FUSRAP waste is by-product material, which is defined in the Atomic
Energy Act of 1954 [Public Law 703, Aug. 30, 1954, 42 U.S.C. 2014 Section II(e)(l)] as
"any radioactive material (except special nuclear material) yielded in or made
radioactive by exposure to the radiation incident to the process of producing or
utilizing special nuclear material" [2], While by-product material is excluded from the
Resource Conservation and Recovery Act as defined in He(2), there is some question
regarding standards for disposal of by-product wastes that are mixed with non-
radioactive hazardous materials. Guidance is being prepared by an interagency
working group for the disposal of mixed IIe(2) by-product waste [2].
FUSRAP wastes have been characterized in the draft Environmental Impact
Statements applicable to the various sites. These types of wastes most often consist of
soil and building rubble that is contaminated by ore or residue from ore processing.
Contamination frequently occurs when wind and water borne particles, from outdoor
piles of higher activity material, are mixed into soil. On occasion, transportation by
moving water, or deliberate removal of the material for construction fill, has scattered
wastes to many "vicinity properties" surrounding the original storage site.
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Most of the radionuclide contaminants consist of U-238 and the products in its
decay series. At some sites, Th-232 and its decay products are also of
concern. The decay chains for U-238 and Th-232 series radionuclides are shown in
Figures 2 and 3, respectively [7]. An example (Middlesex, NJ site) of radionuclide
concentrations in FUSRAP wastes is given in Table 2. FUSRAP soil wastes also
contain metallic substances, as shown in Table 3.
For FUSRAP wastes in general the prinicpal hazard is from Ra-226 and its
short-lived decay products (see Figure 2) [7]. Because this waste (at least as
determined at the Middlesex, NJ site) [8] is in secular equilibrium, the hazard will
exist as long as the U-238 is present Average concentrations range from 20 to 200
pCi/g for U-238, and from 50 to 500 pCi/g for Th-230 and Ra-226. Localized
concentrations, however may exceed these values by factors of 10 to 100 [9],
Nevertheless, in at least some cases, the overall activity of FUSRAP wastes is
sufficiently low that the wastes are classified as nonradioactive for transportation
purposes [9].
Table 4 indicates that much of the waste is in the form of soil, typically having
a significant percentage of very fine grained material. For example, waste from the
Niagara Falls site are 37 percent sand-size, 26 percent silt, and 37 percent clay [9].
Other sites have much larger average grain sizes since the bulk of the waste is building
rubble. In some cases, the wastes contain significant amounts of wood or leaf litter.
Radiological impacts from ocean disposal of FUSRAP waste would be small, as
can be seen by comparing the amount of activity naturally present at a disposal site
with the amount of activity in the FUSRAP waste. The sediment characteristic and
radioactivity data that follows are from the Atlantic Ocean 3800 m disposal site.
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A site having an area of 2500 km2 has been assumed. Only the sediment to a
depth of S cm has been included because it is in contact with the sediment/seawater
interface through bioturbation. Density of the sediment is taken to be 1.1 g/cm3. The
activity of *»U is 14 pCi/g [11], which is in the midrange of oceanic sediments (0.1 to
27 pCi/g) [10], and was determined as the average of 12 samples analyzed at
Brookhaven National Laboratory (BNL) for the Atlantic 3800 meter site. Activity of
**Ra in this sediment was 0.56 pCi/g [11], with the range for oceanic sediment being
0.3 to 39 pCi/g [10].
Using these values and the data presented earlier for FUSRAP waste, a
comparison can be made. The activity in the surOcial sediment of the entire site is
190 Ci and 7.8 Ci for ««U and »Ra respectively. If the entire inventory of FUSRAP
waste (1.2 x 10" m3) is dumped at this site, an event that will not occur, the activity
deposited will be between 0.55 and 5.5 Ci of "«U. This is between 1 and 3 percent of
the **U activity naturally present at the site. The activity of '"Ra that will be
deposited from the waste is between 1.4 and 14 Ci, bracketing the amount naturally
present at the site with the maximum FUSRAP deposition being about double the
natural activity.
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80-
Figure 2. The U-238 decay series, showing the half-life of each isotope [7].
90 -
85
80
'Th. RdTh 212
'91
"»Ac.M.Th,
Th, Th
1.41 X 1010 v
"Ra. ThX
J
"°Rn, Tn
. 55.6 s
"'Po.ThCT tT
0.3 ia JT 64% 2I«Po. ThA
. '"Bi/ThC /. 0.1S«
t^60.6min\t^
'fe, fc/36* ...p,,.ThB
t/ o Decay
K^ 0 Decay
if Denotes major branch
125
130
135
N
140
145
Figure 3. The Th-232 decay series, showing the half-life of each isotope [7].
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Table 2. Radioisotoues* in FUSRAP Waste F81
Isotope Mean
Concentration (pCi/g)
»«U 142
^Th 108
»»Ra 108-
*«Pb 102
95
7'
6
S
5"
"Tl 4-
When analyses were below detection limit, the limit was halved to compute the mean.
Table 3. Mean Concentrations of Trace Metals' in Middlesex FUSRAP Waste [81
Element Mean (ppm)
As 29
Ag <6
Be 5*
Cd
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TABLE 4
PROJECTED QUANTITIES AND CHARACTERISTICS OF WASTES COLLECTED BY FUSRAP ACTIVITIES"
State and site
California
Oilman Hall, Univ. of
California, Berkeley
Connecticut
Seymour Specialty Wire
Illinois
Pa I os Park Forest Preserve
Cook County
Laboratories at Univ. of
Chicago, Chicago
National Guard Amory
Site area
(ha)
MDb
ND
7.7
3.8
ND
Estimated
waste, vo I Line
on
23C
33
d
57*
38
Principal constituents
Floor tile, piping
Rubble, metal
Soil, rubble
Building masonry, floor
tile, wood, glass,
carpet
Building masonry and
Identified contaminants
Alpha, 137Cs
238u
m 23J{, ^V 13V
155Eu, ^Sr, ^Co
238U, alpha, beta-game
238u
rubble
material, floor tile.
Subtotal
95
Maryland
U.K. Grace and Company
Curtis Bay
Massachusetts
Shpack Landfill, Norton
Ventron, Beverly
3.2
ND
27,526
306'
3,823
Soil
Soil, concrete, metal,
rubble
Soil, concrete, rubble,
metal, and building
material
238U.
. 210Pb
Subtotal
4,129
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TABLE 4
PROJECTED QUANTITIES AN1
Site area
State and site (ha)
Missouri
St. Louis Airport 8.8
St. Louis Airport (vicinity 1
properties). St. Louis
Latty Avenue, Hazeluood 4.7
Naltinckrodt, Inc. NO
Subtotal
Michigan
General Motors, Adrian NO
New Jersey
E.I. du Pont de Nemours 283
and Co., Deepuater
Kellex Research Facility, 6.2
Jersey City
Middlesex Municipal 1.2
Landfill, Middlesex
Middlesex Sampling Plant, 3.9
Middlesex
W.R. Grace/Sheffield NO
Brook/other properties,
Wayne and Peojuamock
Stepan Chemical Co., Bailed MO
property and private
properties on Latham St.
and Davison Ave., Maywood
D CHARACTERISTICS
Estimated
waste. volume
107,034
15,290
68,807*
53,522
244,653
153
5,350
k
134"
*
25,232*
• _
43,560*
91,740k
206.4221
! OF WASTES COLLECTED BY 1
Principal constituents
Soil
Soil
Soil, rubble
Soil, building Materials,
rubble
Soil, building Material,
and metal
Soil, building Material,
rubble, road Material
Soil
Soil
Soil, building material.
rubble
Soil, rubble
Soil, rubble
7USRAP ACnvrnES (COD.L)
Identified contaminants
238JJ 230Th 226Ra
238U, 226Ra
gju, *£.,. ^AC.
238^'230pa* 226Ra
tto
238U
*v>o *yvy fy£. 11 A
•bJQ|| &J(*m, *****& m DK
T~TJ, ^la, ^Th, 230Th,
Pb
238U
23o, 3T3Tk 22oDA
£j£\nf Ka
232Th 228Th 226Ra 23^
232.., 226 235..
-V»»™»..A Ra» "•
238U, ^K
Subtotal
372,458
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TABLE 4
PROJECTED QUANTITIES
Site area
State and site (ha)
New Mexico
Acid/Pueblo/Los Alamos 51.6
Canyons, Los Alamos
Bayo Canyon, Los Alamos 137
Chupadera Mesa, White Sands MD
Subtotal
Hew York
Linde Air Products Div., 22.2
Tonawanda
NL Bearings Plant and ND
private properties on
Central, Paltter, and
Yardboro Avenues,
Albany, Cotonfe
Niagara Falls Storage Site 525
(vicinity properties),
Lewis ton
Ashland Oil Co. (Mo. 1) 3
Tonawanda
Ashland Oil Co. (Ho. 2) 1
Tonawanda
Seaway Industrial Park, 4.8
Tonawanda
AND CHARACTERISTICS
Estimated
waste. volume
(•O
298m
1,163°
NO0
1,461
19,727
22,938p
36.69711
64.226
36,701
37,007
OF WASTES COLLECTED BY
Principal constituents
Soil
Soil, building material,
rubble
Soil
Soil, building material.
equipment
Soil, building material,
equipment, rubble
Soil
Soil
Soil
Soil
FUSRAP ACTIVITIES (cont.)
Identified contaminants
O-JQ 1X1
^«Pu, Mi^ fission
Fission products
•Oty
»V. »«. "Si
23& 7*1 226.
^u, ^^h, ^^la
226Ra
Subtotal
217,296
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TABLE 4
PROJECTED QUANTITIES AND CHARACTERISTICS OF WASTES COLLECTED BY FUSRAP ACTTVmES (com.)
Estimated
waste volume
00
State and site
Site area
(ha)
Principal constituents
Identified contaminants
Oregon
Albany Metallurgical
Research Center, Albany
Pennsylvania
Universal Cyclops, Inc.,
Aliquippa
NO
0.3V
2,294
23
Soil, building material,
plumbing
Soil, concrete, metal
alpha, beta-
Total (all sites)
870,144
*Taken from Reference 1.
bMot determined.
Remedial action completed; 25 m3 of waste sent to LLW burial ground at NTS.
dAuthoHzed for radiological surveillance only. Estimated 15,830 m3 of stabilized waste entombed onsite being monitored.
Remedial action completed; 57 m3 of waste sent to ECU, Idaho Falls, for disposal.
Remedial action partially complete; <1 m3 of waste generated.
'Remedial action partially complete; 10,322 • of offsite property waste transferred to Interim storage onsite.
Remedial action completed; 134 m3 of waste sent to LLW burial ground at Barnwell, SC.
Itemedial action partially complete; 11,469 • of waste transferred'to Middlesex Sampling Plant for Interim storage.
'Remedial action partially complete; 26,763 m of offsite property waste transferred to Interim storage onsite.
Remedial action partially complete; 2,675 m of waste transferred to Interim storage onsite.
ntemedial action partially complete; 30,589 m of offsite property waste transferred to Interim storage onsite.
""Remedial action completed; 298 m3 of waste to LLW burial ground at LAML.
"Remedial action completed; In-situ stabilization of 1,162 m3 of waste.
°Remedial action not required.
^Remedial action partially complete; 612 m of offiste property waste transferred to Interim storage onsite.
Remedial action partially complete; 34,816 m of offsite property waste transferred to Interim storage onsite.
rTotal floor area that was surveyed; only isolated patches of radioactive contamination were found.
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2. PROPOSED WASTE PACKAGE PERFORMANCE CRITERIA FOR DEEPSEA
DISPOSAL OF LLW
Performance criteria have been developed for ocean disposal of LLW packages,
containers and waste forms [6]. For each criterion in this report, an associated
specification is recommended that gives a value or condition to be met for a waste
package to be acceptable for ocean disposal* The specifications, therefore, provide
values against which waste packages (or their components) can be evaluated or from
which information gaps can be identified. The performance criteria were developed
based on the following assumptions [6].
2.1 Assumptions
•Existing Federal regulations govern the interim storage, transportation and
disposal of radioactive wastes. Waste packages intended for ocean disposal
should meet all minimum Federal requirements, including relevant United
States international treaty commitments.
•Only LLW, as defined in the Low-Level Radioactive Waste Policy Act (PL
96-573), is considered for ocean disposal.
•The disposal site has an average water depth greater than 4,000 meters.
•Package performance criteria are based upon a multiple barrier concept which
considers the contributions of engineered barriers (waste form, container) and
natural barriers (water column, physical and geochemical properties of the
sediment).
13
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2.2 Waste Package Performance Criteria and Specifications
1. Criterion:
Specification;
The package should have adequate density to ensure sinking
to the seabed.
The specific gravity of the package should not be less than
1.2 to ensure sinking to the seabed.
2. Criterion;
Specification;
The package should be designed to remain intact upon
impact with the sea surface and the seabed.
The package should be designed to maintain its
integrity upon impact with the sea surface and the
ocean floor at a minimum calculated and/or measured
velocity of 10 m/s.
3. Criterion;
Specification:
The container should be capable of maintaining its contents
until all radionuclides have decayed to acceptable limits, as
determined by appropriate regulatory authorities.
The container should have an expected lifetime in the
deepsea environment of 200 years or 10 half-lives of
the longest lived radionuclide, whichever is less.
4. Criterion:
Specification:
Liquid radioactive waste should be immobilized by suitable
solidification agents.
Liquid wastes should be solidified to form a homogeneous,
monolithic, free-standing solid containing no more than 0.5
percent of free or unbound liquid by volume of the waste
form.
14
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5. Criterion;
Specification;
Buoyant material should be excluded or treated to preclude
its movement or separation from the waste form during and
after disposal.
Buoyant materials should be treated to form a homogeneous
free-standing monolithic solid having a specific gravity of
not less than 1.2.
6. Criterion;
Specification;
The package should be able to withstand the hydrostatic
pressure encountered during and after descent to the seabed.
The triaxial compressive strength of a package should be 25
percent greater than the pressure encountered at the
disposal depth. Uniaxial compressive strength of a package
may be measured (triaxial strength is taken to be 4 times
the uniaxial compressive strength). Pressure equalization
devices that allow only ingress of water can be used.
7. Criterion:
Specification;
8. Criterion;
Specification;
The leach rate of the waste form should be as low as
reasonably achievable (ALARA).
The leach rate for Cs-137, Sr-90 and Co-60, as well as other
radionuclides of concern in the waste, should be no greater
than regulatory guidelines as measured by the ANS 16.1
Leach Test for leaching in seawater.
Particulate wastes should be rendered nondispersible.
Paniculate wastes, such as ashes, powders and other
dispersible materials should be immobilized by a suitable
solidification agent to form a homogeneous, monolithic, free-
standing solid.
15
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9. Criterion; Free radioactive gaseous wastes should be prohibited from
ocean disposal.
Specification: No radioactive gaseous wastes should be accepted for ocean
disposal unless they have been immobilized into stable waste
forms such that the pressure in the waste package does not
exceed atmospheric pressure.
10. Criterion: Mixed wastes, which contain hazardous constituents, should not
be disposed of at a LLW ocean disposal site.
Specification: Wastes that contain constituents prohibited, as other than con-
taminants in 40 CFR, Subchapter H, Subpart B, part 227,6
should not be disposed of at a LLW ocean disposal site.
11. Criterion; The waste should be physically and chemically compatible with
the solidification agent
Specification; Waste forms should retain their structural stability after
immersion in seawater for 180 days.
In view of recent EPA/ORP bioeffects studies, an additional consideration is that
LLW should be present in quantities to ensure that no localized, adverse effects would
occur, as determined by using bioassay/bioeffects testing procedures, should the waste
package rupture. Further, any dose to a sensitive, benthic species for the radionuclides
under consideration should be at or below the lowest observable effects-levels (LOEL's)
measured by laboratory exposure procedures. This concept will presumably supercede
proposed criterion number 3, above, which requires a container lifetime of sufficient
length that the contents will have decayed to innocuous levels before the container fails.
However, uncertainties of the exact activities allowed and how the dose to biota should
be determined, based on any given failure scenario, preclude the use of this concept in
evaluating the disposal techniques presented later in this report.
16
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3. TECHNIQUES FOR OCEAN DISPOSAL OF FUSRAP WASTES
Five techniques or methods have been developed for ocean disposal of FUSRAP
waste. An alternative (technique) in which "as is" or untreated FUSRAP waste, without
containerization, is dumped into the ocean was not considered because of the dispersive
nature of the waste [3]. Each technique is presented with a level of detail that allows
for a comparison of relative merit Each was also evaluated in terms of the proposed
waste package performance criteria described in Section 2. A listing of advantages and
disadvantages is provided.
3.1 Technique #1 - Disposal of Unsolidified Waste in a Closed Barge
3.1.1 Description. Untreated waste is transported by dump truck to a dock
where it is transferred to a barge. The barge conveys the waste to the disposal site and
serves as the disposal container. After being towed to the disposal site the barge is
sunk by flooding it with water. Consequently, the barge must be constructed in such a
way that it can be easily loaded and then sealed to ensure that waste cannot be
released during disposal. Pressure equalization devices are necessary to maintain the
integrity of the barge during descent Technique #1 is illustrated in Figure 4.
Note that two sequences of events are possible after the barge is sunk. In the
first situation, the barge remains intact after its descent to the seafloor. Since the
barge was flooded, the waste is already in contact with water. However, the harge is
intact and the waste is contained until the barge corrodes to the point of failure.
While releases of contaminants that have leached into the water in the barge will occur
with time, the waste will not be dispersed until corrosion destroys much of the hull.
17
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The lifetime of the barge's hull is a function of corrosion rate (the general
corrosion rate of mild steel in the deep Atlantic is about 0.08 mrn/yr, although pitting
may be much faster) and metal thickness. Assuming a typical hull thickness of 10mm,
a maximum period of barge integrity ("lifetime") would be approximately 120 years.
In the second possibility, a barge could break-up during descent or impact with
the seafloor; allowing the wastes to disperse and come into contact with marine life.
3.1.2 Evaluation. Technique #1 does not meet proposed waste package
performance criterion 8 which requires that participate wastes be rendered non-
dispersible by solidification. Because a barge is used as the waste container, there are
questions regarding the ability of a heavily laden barge to survive the descent and
impact on the seafloor, without breaching, as illustrated in Figure 4. Some means of
ensuring that the barge fully floods during descent is necessary. In addition, one way
valves would be required to let water enter during descent so that pressure inside and
outside the hull are equalized, thus minimizing the chances of rupture.
Generalized advantages and disadvantages associated with using technique #1 are
listed below. The advantages are precluded by the failure of this disposal method to
satisfy proposed waste package performance criterion # 8 because waste solidification
is not employed in this technique.
Advantages Disadvantages
• No solidification costs . Waste is dispersible
• No volume increase . May require specially designed
• Reduced transportation costs barges
• Requires large number of barges
18
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OCEAN DISPOSAL OF FUSRAP WASTE
Technique # 1 Unsolidified Waste/Closed Barge
-------
3.2 Technique #2 - Disposal of Unsolidified Waste in Closed Containers
3.2.1 Descrption. Untreated waste is loaded into containers at the storage site.
These containers may be of any size. It is envisioned, for convenience, that 55-gaIlon
drums would be used; but large, steel, 210 ft3 liners or some other configuration would
also be appropriate. The sealed containers are transported by truck to a dock where
they are loaded onto a ship. The ship transports the containers to the site where they
are dumped overboard. The act of disposal may actually be via a ramp to minimize
impact between the container and the sea surface. Each disposal container would
require a pressure equalization device to allow water to enter, but not to escape,
thereby equalizing the hydrostatic pressure on the container during its descent to the
seafloor. Once disposed in the ocean, the containers will be subject to the effects of
corrosion. Thus, the wastes will eventually be exposed and subject to physical and/or
biological transport and dispersion. Technique #2 is depicted in Figure 5.
3.2.2 Evaluation. Technique #2, as was the case for Technique #1, does not
meet criterion 8 which requires solidification of dispersible waste. Pressure
equalization devices would be required since loose, soil-like waste cannot support
containers against the hydrostatic pressure of the deep ocean. Thin-walled containers,
such as 55-gallon mild steel drums, cannot be expected to survive more than 10 to 20
years. However, thicker steel containers or other materials, such as some polymers,
may last significantly longer. There is a degree of uncertainty as to how many, or what
percentage, of these smaller (than barge-sized) containers would remain intact after
impact on the ocean bottom. It is likely, however, that the percentage of smaller
containers subject to such damage would be less than expected with the barges used in
Technique #1.
20
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OCEAN DISPOSAL OF FUSRAP WASTE
Technique # 2 Unsolidified Waste/Closed Containers
LOAD WASTE
INTO
CONTAINERS
TRANSPORT
TO DOCK
TRANSFER
SHIP
TO
DUMP
WASTE
PACKAGES
PACKAGES
CONTACT
OCEAN BOTTOM
CONTAINERS
CORRODE
CONTENTS
LEACH
STEAU TO
DISPOSAL SITE
Figure 5. Disposal of Unsolidified Wastes in Closed Containers
-------
Advantages Disadvantages
• No solidification costs
• No volume increase • Cost of containers
• Minimized dispersion during
handling, transportation and • Increased transportation costs
disposal
• Control over distribution of waste
packages on ocean floor
33 Technique #3 - Disposal of Solidified Waste in a Closed Barge
33.1 Description. As stated in waste package performance criterion 8, the waste
materials should be immobilized with a solidification agent before disposal, to
minimize their dispersion after disposal. This technique, as do techniques 4 and 5
which follow, uses hydraulic cement as the solidification agent, but other materials may
also be suitable for this purpose. These three techniques only differ in when or where
the waste is solidified, and in the method used for disposal.
In technique #3 (see Figure 6), the waste is transported to a barge-loading dock
where it is mixed with hydraulic cement (e.g., Portland cement) and water. The wet
mixture is then poured or pumped into a barge and allowed to set (harden).
Afterward, the barge is sealed, towed to a disposal site and flooded for sinking. With
time on the seafloor, as with smaller containers, the barge will eventually corrode to
the point of failure. The solidified waste would then be subject to disintegration by the
action of currents and biota, but the radionuclides in that waste would be released for
dispersal at a slower rate than would unsolidified wastes from a corroded barge.
22
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OCEAN DISPOSAL OF FUSRAP WASTE
Technique # 3 Solidified Waste/Closed Barge
LOAD WASTE
ON TRUCKS
TRANSPORT
TO DOCK
SCUTTLE
BARGE
BARGE
CONTACTS
OCEAN
BOTTOM
BARGE
CORRODES
CONTENTS
LEACH
MIX WASTE
WITH
CEMENT
TOW BARGE
TO DISPOSAL
SITE
PUMP
MIXTURE
INTO BARGE
ALLOW TIME
FOR CEMENT
TO HARDEN
Figure 6. Disposal of Solidified Wastes in A Closed Barge
-------
33.2 Evaluation. Technique #3 appears to meet all of the waste package
performance criteria, with the exception of the container lifetime criterion (#3). One
unknown factor is the ability of a barge to survive descent and impact on the ocean
floor without breaching* The mass of solidified waste may improve survivability of the
barge by making it more rigid, and more stable during descent, as compared to a
barge containing loose waste.
Advantages Disadvantages
• Reduced transportation cost from • Dispersible waste transported and
site of origin to dock handled at dock
• Waste rendered non-disperstble • Solidification costs
• Volume increase
• May require specially designed
barges
• Requires large number of barges
3.4 Technique #4 • Disposal of Solidified Waste in Closed Containers
3.4.1 Description. The waste is mixed with water and hydraulic cement at the
storage site. This can be done in large mixers and subsequently poured into
containers. After allowing time for the mixture to harden, the drums are transported
to the dock and loaded onto a ship. The waste containers are then transported to the
disposal site where they are dumped. To eliminate damage from the effects of
hydrostatic pressure during descent to the seafloor, the containers will need pressure
equalization devices. The containers will eventually corrode, ultimately exposing the
solidified waste to seawater. This technique is illustrated in Figure 7.
24
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OCEAN DISPOSAL OF FUSRAP WASTE
Technique # 4 Solidified Waste/Closed Containers
MIX WASTE
WITH
CEMENT
POUR
MIXTURE
INTO
CONTAINER
DUMP
WASTE
PACKAGES
C3
STEAM TO
DISPOSAL
SITE
PACKAGES
CONTACT
OCEAN
BOTTOM
CONTAINERS
CORRODE
CONTENTS
LEACH
ALLOW TIME
FOR CEMENT
TO HARDEN
LOAD WASTE
ON SHIP
LOAD WASTE
ON TRUCKS
TRANSPORT
TO DOCK
Figure 7. Disposal of Solidified Wastes in Closed Containers
-------
3.4.2 Evaluation. Technique #4 is much the same as technique #3 in that it
passes all of the proposed waste package performance criteria, except for container
lifetime. There is less uncertainty about the ability of small containers to survive
descent and impact on the bottom when they have been filled with solidified waste,
than there is about larger containers (e.g. barges) filled with unsolidified waste.
Advantages Disadvantages
• Waste is rendered non-dispersible • Solidification costs
at site of origin • Volume increase
• Control over distribution of waste • Cost of containers
packages on ocean floor • Increased transportation costs
3.5 Technique #5 - Disposal of Solidified Waste without a Container
3.5.1 Description. This technique (see Figure 8) takes advantage of the low
activity of the FUSRAP waste by eliminating containers. At the storage site, the waste
is mixed with hydraulic cement and water and cast into block-molds where it hardens.
For larger waste forms, some reinforcement and lifting eyes may be included in the
casting. After hardening, the molds are removed and the waste (in block waste forms)
is transported to a dock and loaded onto the disposal ship. After dumping the waste
blocks at the disposal site, leaching starts immediately.
3.S.2 Evaluation. This concept is significantly different than those previously
described because no container is used. Consequently, it does not meet proposed waste
package performance criterion # 3. However, the waste is not dispersible at any time
after the blocks are produced as long as they are not damaged during loading and
transport.
26
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OCEAN DISPOSAL OF FUSRAP WASTE
Technique # 5 Uncontained Solidified Waste
MIX WASTE
WITH
SOLIDIFICATION
AGENT
STEAM TO
DISPOSAL
SITE
DUMP
WASTE
FORMS
CAST
MIXTURE
INTO
MOLDS
LOAD WASTE
ON SHIP
WASTE FORMS
CONTACT
OCEAN
BOTTOM
WASTE
FORMS
LEACH
ALLOW TIME
FOR CEMENT
TO HARDEN
TRANSPORT
TO DOCK
REMOVE
WASTE FORM
FROM HOLDS
LOAD WASTE
ON TRUCKS
Figure 8. Disposal of Solidified Wastes Without Container(s)
-------
Advantages
No Container costs
Waste rendered non-dispersible
at site of origin
4. RESULTS AND DISCUSSION
4.1 Summary of Results
Disadvantages
Solidification costs
Volume increase
Increased transportation costs
Table 5 summarizes the results from evaluating disposal techniques and proposed
waste package performance criteria.
Criterion # 7 (teachability), is not addressed in this discussion because it is site
dependent It's applicability should be determined/evaluated by site-specfic monitoring
and modeling.
The question of mixed (hazardous and radioactive) waste has yet to be resolved
for FUSRAP wastes. It was not evaluated herein since this report focuses on packaging
criteria.
Waste package performance criterion # 3 is not specific about how long a
container must last because the container lifetime is based on the half-lives of whatever
radionuclides are in the waste. FUSRAP waste loses its hazardous constituents
(primarily Ra-226) at a rate governed by the half-life of U-238, which is 4.47 x 10*
years. Obviously, this is longer than any container could last, so none of the disposal
techniques in this report meet that criterion.
It is important to note that a lowest observable effects level (LOEL) criterion
may be promulgated for ocean disposal of LLW. In that event, proposed waste package
28
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performance criterion # 3 (container lifetime) would be superceded and the amount of
activity in each container would become important Additional information, about
acceptable doses to biota, waste package release models and near-field dispersion rates,
is needed to apply the LOEL concept to regulating ocean disposal of LLW.
Criterion
1. Density
2. Impact
3. Container
4. Liquids
Conformance with Proposed Waste Package Performance Criteria
1
Yes
?
No
Yes
[aterial Yes
c Pressure Yes
Disi
2
Yes
Yes
No
Yes
Yes
Yes
josal Technique
3
Yes
•
No
Yes
Yes
Yes
Number
4
Yes
Yes
No
Yes
Yes
Yes
5
Yes
*
No
Yes
Yes
Yes
7. Leachability *
8. Dispersibiliry No
9. Gases Yes
10. Mixed Waste ?
11. Compatibility NA
NOTES TO TABLE
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
NA
Yes
Yes = Fulfills Criterion
No = Does Not Fulfill Criterion
? = Unknown For Criterion
* = Leach Rate Unspecified
NA = Not Applicable
Yes
Yes
29
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4.2 Discussion
In evaluating the five techniques/methods presented in this report, it is apparent
that disposal of FUSRAP wastes presents certain problems relative to the proposed
waste package performance criteria. This is a result of the very long half-lives of the
major contaminants in FUSRAP waste. These issues are discussed below.
4.2.1 Containers. Most FUSRAP wastes are "byproduct" wastes, having a
different radionuclide content than the types of LLW considered when the proposed
waste package performance criteria were developed. Because the long-lived FUSRAP
"byproduct" wastes were not considered at that time, a discrepancy exists between the
proposed container lifetime criterion (# 3) and its 200-yr expected lifetime
specification. This container lifetime specification becomes irrelevant for such long-
lived FUSRAP radionuclides as U-238. For very long-lived radionuclides, the only
reasonable argument for requiring a container is to keep the waste from dispersing
during disposal, allowing it to arrive at its intended location on the ocean bottom.
Therefore, the entire concept of using containers to retain FUSRAP wastes long enough
for radioactivity to decay to "acceptable limits" is inappropriate.
In addition, if the question of container lifetime is ignored and if it is
acknowledged that a container is desirable to minimize dispersion, another practical
matter arises. That is the large number of containers that would be required for ocean
disposal of all FUSRAP wastes. If barges with a capacity of 2600 m* each, see [3], are
used for unsolidified waste, more than 450 barges are required. If 55-gallon drums are
used, then 5.8 x 10« drums will be needed. If the waste is to be solidified, these
numbers double. Thus, as shown above, there are at least two reasons to question the
use of containers for ocean disposal of FUSRAP wastes.
30
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Introduction of the LOEL concept to this discussion would eliminate the need to
provide a guaranteed lifetime for the containers. Instead, it sets limits (unknown at
this tune) on the amount of activity allowed in any one container. Significant
questions arise when one takes a target dose to biota and works backward to obtain an
allowable total activity per container. The geochemistry of the elements of concern will
be important in determining how releases occur from the waste and at what rate. In
the case of uranium, releases will be particularly sensitive to the oxidation-reduction
environment This is also the case when discussing corrosion rates of containers that
are partially embedded in the sediment The near-field dispersion of dissolved
radionuclides and their interaction with the sediment and nepheloid materials will also
significantly impact dose calculations. It is doubtful that enough is known about these
processes in the deepsea to derive any useful dose values.
4.2.2 Solidification. Disposal techniques 3, 4, and 5 use the concept of solidi-
fication to minimize dispersibility of the waste in accordance with criterion #8, which
states that "particulate wastes shall be rendered nondispersible." A key issue that
arises here, then, is whether there is any rationale for minimizing dispersion of
FUSRAP wastes after disposal.
No solidification agent can last long enough to have any impact on doses caused
by ingestion of this waste. For example, waste solidified by cement will be reduced to
participates long before even a small part of the U-238 half-life has passed. Thus, as
with containerization, solidification of FUSRAP wastes will provide no long-term
benefit
4.23 Leaching. Proposed criterion # 7 requires that the leach rate of a waste
be "as low as reasonably achievable11 and that leach rates will be no greater than
31
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regulatory guidelines as measured by the ANS 16.1 test method. The concept of
leaching is connected with solidification of waste in the ANS 16.1 test methodology. In
the same way that solidification of FUSRAP waste provides no long-term benefits, leach
rate limits do nothing to minimize long-term doses. Even very low leach rates will
ultimately result in the release of all soluble contaminants because of the very long
half-lives.
In the long-term, the amounts of U-238, Th-232 and their decay products
present in seawater as a result of FUSRAP disposal will be controlled by the
geochemical behavior of these elements in seawater, and the nature of the marine
environment in which they are dumped. Thorium, for example, associates itself with
particles very readily. Consequently, its residence time in seawater is short; about 100
years or less [13]. Uranium, in oxic seawater, is stable in the U*6 state as UO2(CO3V
and has a mean residence time of 400,000 years [13]. If, however, the environment is
not oxidizing, but reducing, uranium is present as U+4 which reacts to form lower
solubility compounds and is, therefore, much less mobile than the oxidized form [14].
Radium is more soluble than its parent element and much of the radium in seawater
is released from sediment where it is produced [10]. Radium-226 concentrations in
Atlantic Ocean bottom water are typically about 0.1 pCi/1. Disposal of FUSRAP wastes
from the Niagara Falls storage site into an area of approximately 2.6 km in diameter
and 7 cm thick, would lead to an increase in Ra-226 concentration of 0.002 pCi/1 in a
oue-meter-thick layer of water moving over the waste [15].
5. CONCLUSIONS
Disposal techniques 3 and 4, described in this report, meet the proposed waste
package performance criteria in that the wastes are both contained and solidified.
32
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Solidification, however, will approximately double the volume of waste for
disposal. In addition, solidification (e.g^ using portland cement) also would require
containers. If barges, with capacities of 2600 m* each, are used as containers,
approximately 900 would be needed. If 55-gallon drums are used, almost 12 x 10*
would be needed.
From the previous discussions, it is evident that the proposed waste package
performance criteria for LLW are inappropriate for regulating by-product materials
containing long-lived istopes (e.g. FUSRAP wastes). In proposing these criteria [6], it
is made clear that they were intended for regulating LLW containing radionuclides
such as Cs-137, Sr-90 and Cb-60. These are short half-life radionuclides (compared to
the isotopes in FUSRAP waste) which would pass through many half-lives during the
required 200-year container lifetime. The long half-lives of the contaminants in
FUSRAP waste (which are naturally occurring), the very low activity and the large
volume all make solidification and containerization unfeasible.
If the LOEL concept is to be applied to this type of waste, significant questions
regarding geochemistry and near-field dispersion remain to be answered before
reasonable limits can be defined for either FUSRAP (by-product) waste or for LLW.
Thus, the proposed LLW package performance criteria bear little useful
relationship to FUSRAP waste. It is recommended that a new set of criteria be written
for disposal of wastes, such as the FUSRAP materials, which could also be applicable
to other waste types, where solidification or containerization provide, no reduction of
long-term risk.
-------
REFERENCES
[1] U.S. Department of Energy, Integrated Data Base for 1986: Spent Fuel
and Radioactive Waste Inventories. Projections and Characteristics.
DOE/RW-0006 Rev. 2, September 1986.
[2] Fiore, J. and G. Turi, "Progress and Problems in FUSRAP and SFMP
Programs," in Waste Management >88. pp. 357-362, University of Arizona,
Tucson, Arizona, 1988.
[3] Gilbert, T.L, et al, "Alternatives for Management of Wastes Generated
by the Formerly Utilized Sites Remedial Action Program," ANL/EIS-20,
Argonne National Laboratory, Argonne, Illinois, March 1983.
[4] Hunt, Carlton D., "Fate and Bioaccumulation of Soil-Associated Low-
Level Naturally Occurring Radioactivity Following Disposal into a
Marine Ecosystem," EPA 520/1-86-017, Office of Radiation Programs, U.S.
Environmental Protection Agency, Washington, D.C., October 1986.
[5] Bonner, J.S., et al, "Prediction of Vertical Transport of Low-Level
Radioactive Middlesex Soil at a Deep Ocean Disposal Site,1* EPA
520/1-86-016, Office of Radiation Programs, U.S. Environmental
Protection Agency, Washington, D.C., September 1986.
[6] Colombo, P. and Fuhrmann, M., "Waste Package Performance Criteria for
Deepsea Disposal of Low-Level Radioactive Wastes," EPA-520/1-88-009,
Office of Radiation Programs, U.S. Environmental Protection Agency,
Washington, D.C., July 1988.
[7] Friedlander, G., et al, Nuclear and Radiochemistrv. Third Edition, John
Wiley and Sons, N.Y., 684 pages, 1981.
34
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REFERENCES (Continued)
[8] Kupferman, S.L., et al, "Ocean FUSRAP: Feasibility of Ocean Disposal of
Materials from the Formerly Utilized Site Remedial Action Program
(FUSRAP)," in Waste Management '82. Volume H, pp. 471-485, University
of Arizona, Tucson, Arizona, 1982.
[9] U.S. Department of Energy, "Long-Term Management of the Existing
Radioactive Wastes and Residues at the Niagara Falls Storage Site, Draft
Environmental Impact Statement," DOE/EIS-0109D, August 1984.
[10] Fail-bridge, R.W., The Encyclopedia of Oceanography, Reinhold Publishing
Corporation, N.Y., 1021 pp., 1966.
[11] Fuhnnann, M. and Colombo, P., "Sedimentology ahd Geochemistry of Cores
from the 3800 Meter Atlantic Radioactive Waste Disposal Site," BNL-37838,
Report submitted to the U.S. Environmental Protection Agency, Washington,
D.C, 1983.
[12] Di Gregori, J.S. and Fraser, J.P., "Corrosion Tests in the Gulf Floor," in
Corrosion in Natural Environments. ASTM TP 558, American Society for
Testing and Materials, pp. 185-208,1974.
[13] Cochran, J. Kirk, et al, The Geochemistry of Uranium and Thorium in Coastal
Marine Sediments and Sediment Pore Waters, Geochimica et Cosmochimica
Acta. Volume 50, pp. 663-680, 1986.
[14] Cowart, J.B., "The Relationship of Uranium Isotopes to Oxidation/Reduction in
the Edwards Carbonate Aquifer of Texas," Earth and Planetary Science Letters.
Volume 48, pp. 277-283, 1980.
[15] Stall, EA. and Meny-Libbey, P., "Comparison of Land and Ocean Disposal
Alternatives for Bulk Wastes Containing Naturally Occurring Radionucltes," in
Waste Management *85. Volume H, pp. 137-140, University of Arizona, Tucson,
Arizona, 1985.
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