EPA 401-R-95-015
USER'S GUIDE FOR
PRESTO-EPA-POP OPERATION SYSTEM
Version 2.1
August 1, 1995
Developed by
Cheng Yeng Hung, Ph. D.
U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
Washington, DC 20460
-------
EPA 402-R-95-015
USER'S GUIDE FOR
PRESTO-EPA-POP OPERATION SYSTEM
Version 2.1
August 1, 1995
Developed by
Cheng Yeng Hung, Ph. D.
U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
Washington, DC 20460
-------
DISCLAIMER
This user's guide for the PRESTO-EPA-POP Operation System is
the result of integrated work sponsored by an agency of the
United States Government. Neither the United States Government
nor any agency thereof, nor any of their employees, contractors,
subcontractors, or their employees, make any warranty, express or
implied, nor assume any legal liability or responsibility for any
third party's use of the results of such use of any information,
apparatus, product or process disclosed in this report, nor
represent that its use by such third party would not infringe
privately owned rights.
ii
-------
PREFACE
A mainframe version of the PRESTO-EPA-POP model was
developed for generating basic data to support EPA's rulemaking
on the generally applicable environmental standards for the
management and disposal of low-level radioactive waste (LLW).
Since the mainframe version of the PRESTO-EPA-CPG model was
published in December 1987, the Office of Radiation and Indoor
Air has received numerous requests from potential users of the
model urging the Office to convert the model to a form usable on
a personal computer. This effort has subsequently proceeded in
two phases, the simplification of the PRESTO-EPA-CPG/POP model
and the development of the PRESTO-EPA-CPG/POP Operation System.
The simplification of the PRESTO-EPA-CPG/POP model involved
primarily the modification of the DARTAB subroutine so that the
size required by the random access memory can be reduced
considerably without altering the accuracy of the simulation
results. The PRESTO-EPA-CPG/POP Operation System is designed to
assist users to create and edit the main input file for the
PRESTO-EPA-CPG/POP model. It is a user-friendly, menu-directed
operation system. Users will find that the operation of the
system can be simplified and many of the potential errors can be
prevented by employing the operation system program. The
operation system does not include the preparation of the input
file required by the INFIL subroutine because the input file can
be easily handled without an operation system.
The first version of the PRESTO-EPA-CPG Operation System was
published in April 30, 1989, and the second version in September
1993. Subsequently, the first version of PRESTO-EPA-POP
Operation System was published in May 1, 1992, and the second
version in June 1994. The second version of the Operation System
modifies the dose conversion factors and adds the calculation of
cancer incidence to the general population.
111
-------
IV
-------
TABLE OF CONTENTS
Page
LIST OF FIGURES vii
LIST OF TABLES viii
1 INTRODUCTION 1- 1
1.1 Background 1- 1
1.2 Changes in Version 2.1 l- 3
2 DESCRIPTION OF PRESTO-EPA-POP MODEL 2- 1
2.1 General Description of the Model 2- 1
2.1.1 Description of a Disposal Site 2- 1
2.1.2 Description of the Model 2- 3
2.2 Mathematical Formulation of the Model 2- 4
2.2.1 Transport Pathways Involving Water 2- 7
2.2.2 Atmospheric Transport Sources and Pathways 2-23
2.2.3 Food Chain Calculations 2-31
2.2.4 Health Effects Estimates 2-40
2.2.5 Daughter Nuclide In-Growth Effect Correction
2-41
2.3 Health Effects to Regional Basin Population 2-45
2.3.1 Calculation of Regional Basin Health Effects
2-46
2.3.2 Conversion Factors for Regional Basin Health
Effects 2-48
2.4 Development of PRESTO-EPA-POP Code 2-52
2.4.1 Model Structure 2-52
2.4.2 Subroutine Description 2-53
2.4.3 PC Version Of PRESTO-EPA-POP 2-60
2.5 Input File Requirements 2-61
-------
2.5.1 Site and Nuclide Specific Input File 2-61
2.5.2 INFIL Subroutine Input File 2-61
2.5.3 Health Effects Input File 2-61
2.6 Output File Description 2-62
2.6.1 Replication of Input Data 2-62
2.6.2 Radionuclide Summary Tables 2-62
2.6.3 INFIL Input/Output 2-62
2.6.4 Annual Summaries 2-62
2.6.5 Radionuclide Uptake and Concentrations .... 2-63
2.6.6 HESTAB Result Tables 2-63
2.6.7 Cumulative Summary Table 2-63
3 DESCRIPTION OF THE SYSPOP OPERATION SYSTEM 3- 1
3.1 PRESTO-EPA-POP Input Requirements 3- 1
3.1.1 Environmental and Nuclide Specific Input File
3- 1
3.1.2 INFIL Subroutine Input File 3- 1
3.1.3 Health Effects input File 3- 1
3.2 Description of SYSPOP Operation System 3- 2
3.2.1 General 3- 2
3.2.2 System Structure 3- 3
4 SYSTEM INSTALLATION 4- 1
5 SYSTEM OPERATIONS 5- 1
5.1 Start Up 5- 1
5.2 Copy a New Input File from the Standard Input File 5- 2
5.3 Edit the Existing Input File 5- 2
5.3.1 Editing the POP Input File 5- 3
5.3.2 Compare the Input File with Standard File .5-4
5.3.3 Review the POP Input File 5- 5
5.3.4 Delete Radionuclides 5- 5
5.3.5 Insert Radionuclides 5- 6
5.3.6 End of Editing 5- 7
VI
-------
5.4 Test the Current Input File 5- 7
5.5 Execute PRESTO-EPA-POP 5- 7
5.6 Print Out POP.OUT 5- 8
5.7 End of Operation 5- 9
REFERENCES R- 1
APPENDIX A - THEORETICAL BACKGROUND OF INFILTRATION MODEL... A- 1
APPENDIX B - THEORETICAL BACKGROUND OF GROUNDWATER MODEL ... B- 1
APPENDIX C - THEORETICAL BACKGROUND OF DAUGHTER NUCLIDE IN-
GROWTH EFFECTS CORRECTION FACTORS C- 1
APPENDIX D - INPUT FILE FORMAT D- 1
Table D-l Environmental and Nuclide Specific Input File
Dl- 1
Table D-2 INFIL Subroutine Input File D2- 1
Table D-3 Health Effects Input File D3- 1
APPENDIX E - SAMPLE INPUT AND OUTPUT FILES E- 1
Table E-l Environmental and Nuclide Specific Input File
E- 2
Table E-2 INFIL Subroutine Input File E- 7
Table E-3 Health Effects Input File E-ll
Table E-4 Sample Output File E-22
VI1
-------
LIST OF FIGURES
Figure
No. Page
2-1 Environmental Transport Pathways Used in PRESTO Model. 2-2
2-2 Hydrologic Transport Pathways 2- 5
2-3 Atmospheric Transport Pathways 2- 6
2-4 Trench Cap Failure Function 2-12
2-5 Regional Basin Health Effects Analyses 2-46
2-6 PRESTO-EPA-POP Subroutine Structure 2-54
5-1 Main Menu of the Operation System 5- 1
5-2 Sub-Menu for Input File Editing 5- 3
5-3 Instructions for File Editing 5- 4
Vlll
-------
LIST OF TABLES
Table
No. Page
1-1 Function of PRESTO-EPA Family Code 1- 2
2-1 Leaching Options Specified by LEAOPT 2-14
IX
-------
1. INTRODUCTION
1.1 BACKGROUND
Under the Atomic Energy Act, as amended, the U.S.
Environmental Protection Agency (EPA) has the authority to
develop generally applicable standards for the disposal of low-
level radioactive waste (LLW). Technical support for the
standard includes an estimation of the health impacts from the
disposal of LLW in a wide variety of facility types located in
diverse hydrogeological settings.
As an aid in developing the standards, a family of computer
codes, entitled PRESTO-EPA-POP, PRESTO-EPA-DEEP, PRESTO-EPA-CPG,
PRESTO-EPA-BRC, and PATHRAE-EPA has been developed under EPA
direction (EPA87a through EPA87g.) The PRESTO-EPA-POP code was
the first code developed and served as the basis for the other
codes in the family. EPA uses the PRESTO-EPA code family to
compare the potential health impacts (cumulative population
health effects and maximum annual dose to a critical population
group) to the general public and critical population group for a
broad number of LLW disposal alternatives. Table 1-1 provides a
brief description of the function of each member of the code
family. The application of these codes has been described in
detail elsewhere (Hu83, Gal84, Ro84, MeySl, Mey84.)
The PRESTO-EPA-POP (Prediction of Radiation Effects from
Shallow Trench Operation - EPA - Population) code is a computer
code designed to estimate the magnitude of cancer incidence,
fatal cancer deaths, and serious genetic effects in the general
population resulting from the disposal of LLW.
The original PRESTO-EPA-POP model employed the DARTAB
subroutine, EPA's standardized generic submodel for doses and
health effects calculations, which requires a large access file.
The model could therefore only be executed by a mainframe
computer. Soon after the model was released to the public, we
received numerous comments from potential users that it would be
beneficial to new users if the model could be operated on a
personal computer (PC). In responding to the request, the
mainframe version of the model was modified and converted into a
1-1
-------
PC version [Ro87].
In addition, a new user may find that one of the input files
is too complicated to obtain a successful execution of the
program without performing several trial runs. In order to
reduce the potential of making these errors, a user-friendly
input file preparation program was developed to automate the
input file preparation [Hu92].
This user-friendly PRESTO-EPA-POP Operation System Program,
which is designed to simplify the operation of the PRESTO-EPA-POP
model, is the combination of the input file preparation program
and the PC version of the PRESTO-EPA-POP model. The first
version of the Operation System was published on May 1, 1992, and
the second version in September 1993. The second version
(Version 2.0) of the Operation System updated the dose and risk
conversion factors (EPA94) and adopted SI units for activity and
dose equivalent, becquerel (Bq) and sievert (Sv), respectively.
Table 1-1 Function of PRESTO-EPA Family Codes
PRESTO-EPA Code
Purpose
1-2
-------
PRESTO-EPA-POP
PRESTO-EPA-DEEP
PRESTO-EPA-CPG
PRESTO-EPA-BRC
PATHRAE-EPA
Estimates cumulative population health
effects to local and regional basin
populations from land disposal of LLW by
shallow methods; long-term analyses are
modeled (generally 10,000 years).
Estimates cumulative population health
effects to local and regional basin
populations from land disposal of LLW by
deep methods.
Estimates maximum annual whole-body dose to
a critical population group from land
disposal of LLW by shallow or deep methods;
dose in maximum year is determined.
Estimates cumulative population health
effects to local and regional basin
populations from less restrictive disposal
of BRC wastes by sanitary landfill and
incineration methods.
Estimates annual whole-body doses to a
critical population group from less
restrictive disposal of BRC wastes by
sanitary landfill and incineration methods.
1.2 CHANGES IN VERSION 2.1
As briefly stated in the previous section, the changes made
in Version 2.0 from Version 1.0 include: (1) updating the cancer
incidence, fatal cancer, and serious genetic effect conversion
factors, (2) adding a calculation of cancer incidence, and (3)
adopting the International System (SI) units.
The dose coefficients are extracted from the RADRISK data
file (Du80) and the weighting factors are consistent with the
definitions used in ICRP Publications 26 (ICRP 77) and 30 (ICRP
79). The effective dose equivalent is the weighted sum of the
1-3
-------
50-year committed dose equivalent to the organs or tissues.
The cancer risk coefficients are calculated from radiation-
risk models which are based on 1980 U.S. vital statistics. The
genetic-risk coefficients for serious disorders to all subsequent
generations are calculated from the product of the average
absorbed dose to the ovaries and testes up to age 30 per unit
intake before that age. Risk coefficients of 2.60xlO"2 and
6.9xlO'2 Gy1 for low-LET and high-LET radiation respectively are
used for the calculation of risk conversion factors (EPA 89) .
The Version 2.1 Operation System modifies the PRESTO-EPA-POP
model by integrating the daughter nuclide in-growth effects into
the Version 2.0 model. The daughter nuclide in-growth effects
(DNIE) are calculated based on a crude assumption that the
sorption characteristics of the parent and daughter nuclides are
identical throughout the processes of leaching and groundwater
transport. The DNIE are adjusted annually by using the
correction factors derived from Bateman Equations (Ev55).
Finally the corrected effects are integrated over the entire
duration of analysis to obtain the cumulative effects.
The adjustment for DNIE is performed only for those parent
nuclides designated and built into the model. To simplify the
modeling, the adjustment is carried up to 4-member decay chains.
The transport of daughter nuclides is not calculated in the
model.
As stated above, the change made to the Version 2.1
Operation System is on the integration of the DNIE into the
PRESTO-EPA-POP model only, and the interface software for this
version remains the same as that used in Version 2.0. Therefore,
the version number 2.0 appeared in the operation system is
equivalent to Version 2.1.
1-4
-------
2. DESCRIPTION OF PRESTO-EPA-POP MODEL
2.1 GENERAL DESCRIPTION OF THE MODEL
2.1.1 Description of a Disposal Site
The life cycle of a low-level waste disposal site begins
with site selection. Following site selection and regulatory
approval, trenches are dug on the site. Waste materials in
various types of containers are placed into each trench. Once a
section of the trench is filled, the trench is backfilled to
eliminate voids to decrease the potential for subsidence and
cracking of the trench cap. Following backfilling, the trench is
covered with a cap of soil or clay, one to several meters thick,
mounded above grade to facilitate runoff and decrease
infiltration.
In general, hydrologic transport is the principal pathway by
which the general public may become exposed to radioactivity from
LLW disposed in shallow trenches. Figure 2-1 is a schematic
description of the routes that water and any transported
radionuclides may follow from a trench in a LLW disposal site.
The major source of water is from precipitation. The
precipitated water at a site will either infiltrate into the
trench cap, run off the trench area by overland flow, or
evaporate into the atmosphere. The distribution of these
components will depend on the ground cover, steepness of the
slope, and other factors.
Hydrologic transport of radionuclides from a LLW disposal
trench may occur by the infiltrated water or by the overland
flow. The infiltrated water entering the trench leaches out
radionuclides from the waste matrix and becomes contaminated.
This contaminated water may either overflow from the top of the
trench or percolate downward through the bottom of the trench to
the sub-trench soil zone and ultimately enter an aquifer.
Radionuclides that finally reach the aquifer will generally
be transported at velocities less than the flow velocity of the
water in the aquifer. This "retardation" is due to the
2-1
-------
interaction of radionuclides with solid media in the aquifer.
When the radionuclides being transported in the aquifer reach a
well, they will be consumed by the residents through drinking,
irrigation, and cattle feed pathways. Residual radionuclides in
the aquifer are assumed to be transported further downstream and
impose additional health impacts to the downstream population.
PRECIPITATION
ATMOSPHERIC TRANSPORT
RUNOFF
RESUSPENSION
J .
EVAPOTRANSPIRATION
DEPOSITION
EXFILTRATION
STREAM
VEIL
AQUIFER
RADIONUCLIDE TRANSPORT THROUGH AQUIFER
The contaminated water in the trench will accumulate if the
rate of infiltration from the cap exceeds the rate of
Figure 2-1. Environmental Transport Pathways used in
PRESTO-EPA models.
exfiltration out of the trench bottom. When the volume of water
accumulated in the trench exceeds the total void space in the
trench, overflow of trench water onto the ground surface occurs.
The radionuclides in the trench water will then mix with the
overland flow and be further transported into nearby streams.
This contaminated water will potentially be consumed by the local
2-2
-------
residents and by the population downstream via drinking,
irrigation, and cattle feed pathways.
Residents living near the site may also be exposed to the
radionuclides transported from the sites by atmospheric
processes. Radionuclides deposited on the soil surface by trench
overflow, by spillage during disposal operations, or by complete
erosion of the trench cap may be suspended in the atmosphere and
transported downwind where they may be inhaled or deposited on
the ground and vegetation. Deposited radioactivity may
contaminate crops, meat, and milk and enter the food chain.
Deposition on the soil surface may also result in external
radioactive exposure to humans.
2.1.2 Description of the Model
The model has been designed to calculate cancer incidence,
fatal cancer effect, and serious genetic effect in the general
population resulting from the disposal of LLW. The model
simulates the transport of radionuclides from a LLW trench to the
environmental receptors and the human exposures through food
chain pathways. The health effects for the general population
are calculated from the radionuclide uptake rate and the health
effect conversion factors.
The PRESTO-EPA-POP code was designed to accommodate a wide
range of hydrogeologic and climatic conditions. It can also
handle waste leaching and the groundwater transport of nuclides
under partially saturated as well as saturated hydrogeologic
conditions, while taking into account nuclide retardation due to
geochemical processes. The code has features to account for the
dynamic leaching process resulting from deterioration of waste
containers; the farming scenario which simulates farming over the
trench with root uptake of radionuclides from the waste matrix;
and the reduction in the source inventory due to radionuclide
decay during the operational period.
The effect of daughter nuclide ingrowth is incorporated in
the final results by multiplying the parent-nuclide-caused health
effects with its daughter nuclide in-growth effect correction
factor which is defined in later section. Up to the fourth
member of the decay chain is included in this adjustment.
2-3
-------
The radionuclides which are spilled from incoming waste
packages may remain on the ground surface at the close of
disposal operations. These radionuclides would subsequently be
transported either by the atmospheric pathway to the local
population or by the surface water pathway to the nearby stream.
The complex physical and chemical interactions between the
radionuclides and the solid geologic media have been grouped into
a single factor, the distribution coefficient (Kj) . Different Kd
values can be used for soil, trench material, sub-trench soil,
and aquifer.
The subsurface transport path of radionuclides is assumed to
be vertical from the trench bottom to the aquifer and then
horizontal through the aquifer. The flow in the vertical flow
regime is calculated either as saturated or unsaturated flow,
depending on the relationship between the rate of exfiltration,
the degree of saturation, and the properties of the geologic
media. The transport of radionuclides in the aquifer is
calculated by employing Hung's "optimum groundwater transport
model" (Hu81), in which Hung's correction factor is used to
compensate for the effects of longitudinal dispersion.
Three types of submodels are used in the PRESTO-EPA-POP
code: unit response, bookkeeping, and scheduled event. The unit
response submodels calculate the annual response of a given
process. For example, the submodel INFIL calculates the annual
infiltration through an intact trench cap. This annual
infiltration is then apportioned among the transport processes by
the bookkeeping submodels. Other unit response models calculate
the annual average atmospheric dispersion coefficient and erosion
from the trench cap.
Bookkeeping submodels keep track of the results of unit
response submodels and user-supplied control options. For
example, the TRENCH submodel calculates the level of standing
water in the trench and the volume of water leaving the trench.
Annual concentrations of each radionuclide in environmental
receptors, such as well water or the atmosphere, are used to
calculate radionuclide concentrations in foodstuffs. Foodstuff
concentrations and average ingestion and breathing rates are
utilized to calculate the annual average radionuclide intake per
2-4
-------
individual in the local population. These intake data are then
used to estimate dose rates.
The atmospheric transport submodel assumes that the entire
population resides within the same 22.5-degree sector. User-
specified parameters give the fraction of year that the plume
blows in that sector. The transport of the radionuclide from the
source area to a nearby population is calculated by employing the
Gaussian plume diffusion model. Therefore, each member of the
population will inhale the same quantity of each radionuclide.
Each person in a specific local community is assumed to
consume the same quantities and varieties of food, all grown on
the same fields, and obtains his or her drinking and crop
irrigation water from the same source; but the user may specify
the distribution of the sources of drinking and irrigation water
supplies between well and stream.
2.2 MATHEMATICAL FORMULATIONS
Pathways for environmental transport of radionuclides
considered by the model are shown in Figures 2-2 and 2-3.
Transport pathways involving both surface water and groundwater
are illustrated in Figure 2-2. Water may leave the trench
through the exfiltration from the trench bottom or overflow from
the top of trench. Radionuclides in the spilled surface area may
be transported to a surface water body or to the aquifer through
deep underground seepage. The contaminated water may ultimately
reach the local population either from a well or from surface
water.
2-5
-------
SPILLAGE
OVERFLOW
LL
SOIL
SURFACE
LEACHING
BASIN
STREAM
BASIN
POPULATIOf
OCEAN
SINK
TRENCH
LEACHING
VERTICAL
SOIL
COLUMN
SEEPAGE
AQUIFER
GROUNDWATER TRANSPORT
I
SURFACE
WATER
BODY
IRRIGATION
A 4.
SOIL
PLANT UPTAKE
CROPS
AND
ANIMALS
I
DRINKING INGESTION DRINKING
4
LJI lUAkIC
HUM AN b
2-6
-------
Figure 2-2. Hydrologic Transport Pathways,
SURFACE
CONTAMINATION
ERODED
TRENCH
SUSPENSION
AIR
INHALATION]
IMMERSION
HUMANS
(Local Population)
DEPOSITION
IRRIGATION FROM GROUND
INGESTION
CROPS
AND
GROUND
Figure 2-3. Atmospheric Transport Pathways,
2-7
-------
The modelled atmospheric pathways for radionuclide transport
are illustrated in Figure 2-3. Material may reach the atmosphere
from the site soil surface contaminated by overflow or
operational spillage, or by the denuded trench following possible
erosion of the entire trench cap. A member of the population
residing in a local community may ultimately be impacted by
inhalation of or immersion in the suspended materials downwind,
by ingestion of crops contaminated following deposition on soil
or crops, or by direct irradiation from ground surfaces.
The model approach in calculating radionuclide
concentrations in the pertinent environmental receptors is
described in the following two sections.
2.2.1 Transport Pathways Involving Water
Infiltration Through Trench Cap
The basic model for simulating the annual infiltration
through the trench cap assumes a portion of the trench cap will
fail and allow the precipitated water to drain into the trench.
The fraction of the cap which fails is assumed to vary with time.
Due to the distinct nature of the infiltration mechanism
between the intact portion and the failed portion of the trench
cap, the annual infiltration through the trench cap is divided
into two components.
On the intact portions of the cap, the normal infiltration
rate is calculated by the method developed by Hung (Hu83b) which
is described in Appendix A. For the failed portion of the cap,
the infiltration equals to rainfall. Therefore, the volume of
water entering the trench annually is calculated by
Wc = At[fc-Pa + (1 - fc)Wa] (2-1)
where:
Wt = volume of water entering trench in current year (m3) ,
2-8
-------
AC = area of trench (m2) ,
fc = fraction of trench cap that has failed (unitless),
Pa = annual precipitation (m) and,
Wa = annual infiltration (m).
The value of Wt is added to the standing trench water from
the earlier year to calculate the maximum depth of standing water
in the trench for the current year.
The component of annual infiltration through the intact
portion of the trench cap, Wa, is estimated by employing the
infiltration model developed by Hung (Hu83b, Appendix A). The
model simulates the rate of infiltration by solving system
equations which describe the dynamics of overland flow,
subsurface flow, and atmospheric dispersion systems. The basic
equations employed in the model are:
Qo = {(Sine)1/2 H5/3}/n (2-2)
dH/dt = P - E0 - q0 - Q0/L (2-3)
Ep when P + H/At > Ep
P + H/At when Ep > P + H/At > 0 (2-4)
. 0 when P + H/At = 0
Ks when P - E0 + H/At > Ks
P - E0 + H/At when Ka > P - E0 + H/At > 0 (2-5)
L 0 when P - E0 + H/At = 0
2-9
-------
Ks when Zg <
0 when Zg = Zmax
(2-6)
dZg/dt = (qt - q0 + qt)/W_
(2-7)
q, = -DeWp/Zp + Ke
q. < EP - EO
qv = -(Ep - E0)
-1
0 . 5Zp
11
O.S6W, + „
p) _
(2-8)
(2-9)
dZp/dt = -(qp + qc)/Wp
(2-10)
qt =
q0 when Zp > 0
0 when Zp = 0
and
where
qp = -Max(|q,|, |qv|)
(2-11)
(2-12)
Qo
rate of overland flow per unit width of trench
cover (m3/m-hr),
H = average depth of overland flow over the entire trench
cover (m),
L = length of slope or half of trench width (m),
n = Manning's coefficient of roughness,
2-10
-------
9 = average inclination of the trench cover (m/m),
P = rate of precipitation (m/hr),
E0 = rate of evaporation from the overland flow (m/hr),
q0 = rate of percolation from the overland flow system
(m/hr),
Ep = evaporation potential (m/hr),
qA = flux of moisture infiltrating into the trench (m/hr),
q, = flux of pellicular water transported in the liquid
phase (m/hr),
Ks = saturated hydraulic conductivity of the soil (m/hr),
Zg = deficit of gravity water (m),
zmax = maximum deficit of gravity water, equivalent to the
thickness of the trench cover (m),
Wg = component of wetness for the gravity water; under
a fully saturated condition, it is numerically
identical to the porosity for the gravity water
(unitless),
Wp = component of wetness for the pellicular water;
under a fully saturated condition, it is
numerically identical to the porosity for
pellicular water (unitless),
Zp = deficit of the pellicular water (m),
De = hydraulic diffusivity at equivalent wetness (m2/hr),
Ke = hydraulic conductivity at equivalent wetness (m/hr),
qv = flux of moisture being transported in the vapor
phase (m/hr),
2-11
-------
qt = flux of moisture being transformed from gravity
water to pellicular water (m/hr) and,
qp = flux of pellicular water (m/hr).
The amount of annual infiltration through the trench cap is
then calculated by integrating the hourly infiltration over the
entire year.
Trench Cap Modifications
The trench cap may fail by erosion or mechanical
disturbance. In the case of erosion, the annual thickness of
material removed from the trench cap by sheet erosion is
calculated using an adaption of the universal soil loss equation
(USLE) (Wi65).
The annual amount of erosion is subtracted from the cap
thickness for the current year of simulation. If the remaining
thickness is less than 1 cm, the cap is considered to be
completely failed and fc is set to 1.0. The USLE may be written
as:
fc-fi-f.-fe-fp-f,, (2-13)
where
I, = yearly sediment loss from surface erosion (tons/ha),
fr = rainfall factor (fr unit or 100 m-tons-cm/ha) ,
fk = soil erodiability factor (tons/ha/fr-unit) ,
fi = slope-length factor (unitless),
f3 = slope-steepness factor (unitless),
fc = cover factor (unitless),
fp = erosion control practice factor (unitless), and
2-12
-------
fd = sediment delivery factor (unitless)
2-13
-------
The parameterization scheme of McElroy, et al. (McE76) was
used to specify site-specific values of the factors in Equation
(2-13). The rainfall factor, fr( expresses the erosion potential
caused by average annual rainfall in the locality. The soil
erodiability factor, fk, is also tabulated by McElroy, et al. as
a function of five soil characteristics: percent silt plus very
fine sand; percent sand greater than 0.1 mm; organic matter
content; soil structure; and permeability. The factors, fi and
fs, for slope-length and steepness account for the fact that soil
loss is affected by both length and degree of slope. The PRESTO-
EPA-POP code usage of USLE combines both factors into a single
factor that may be evaluated using charts in McElroy, et al. The
factor, fc, represents the ratio of the amount of soil eroded
from land that is treated under a specified condition to that
eroded from clean-tilled fallow ground under the same slope and
rainfall conditions. The erosion control practice factor, fp,
allows for reduction in the erosion potential due to the effect
of practices that alter drainage patterns and lower runoff rate
and intensity. The sediment delivery ratio, fd, is defined by
McElroy, et al. as the fraction of the gross erosion that is
delivered to a stream. Units of I, are converted to (m/yr)
within the code. See Section 2.5 for the description of input
units.
The second method of trench cap failure is mechanical
disturbance due to human intrusion or some other means which
might completely destroy portions of the cap. This phenomenon
can be termed a partial failure, but in reality is a total
failure of some part of the cap. The code user may specify some
rate of cap failure as shown in Figure 2-4.
By specifying appropriate values for the time in Figure 2-4,
the user may selectively simulate the failure of the cap from a
portion of the trench area. Mathematically this function is
represented by
r 0, if t < NYR1
fc = (PCT2-PCTI)(t-NYRl)/(NYR2 - NYR1) + PCT1 (2-14)
if NYR1 s t S NYR2
2-14
-------
PCT2 if t > NYR2
Even though PCT2 might be less than 1.0 in year NYR2, the cap may
ultimately fail completely by virtue of erosion. As fc changes,
the amount of water added to the trench annually also changes.
PCT2
I
NYR1 NYR2
TIME (Years)
Figure 2-4. Trench Cap Failure Function
The amount of water leaving the trench annually via the
trench bottom is calculated by:
VB = (Dw
(2-15)
2-15
-------
and
DM = VM/(AT-WT) (2-16)
where
VB = volume of water leaving trench bottom annually (m3/yr) ,
Dw = depth of water in trench during current year (m) ,
IT = permeability of material below the trench (m/yr) ,
AT = trench area (m2) ,
Vw = volume of water in trench (m3) ,
WT = porosity of trench contents (unitless) , and
L = length of saturated zone (m) .
Water will overflow the trench if the maximum depth of
standing water is greater than the trench depth. If this is the
case, the overflow is calculated by
V0 = (DH - DT)AT-WT (2-17)
where
V0 = volume of water overflowing trench in a year (m3-) ,
Dw = depth of water in trench (m) ,
DT = trench depth (m) ,
AT = trench area (m2) , and
WT = porosity of trench material (unitless) .
Water in the trench may be contaminated by contact with the
waste material. To calculate the concentration of radionuclides
in the trench water exfiltrating out of the trench, two model
2-16
-------
types are used, a dynamic model based on the chemical exchange
and an emperical model based on the annual release fraction.
The user must choose one of the three options shown in Table
2-1 to calculate the concentration of radionuclides in the trench
water.
Table 2-1 Leaching Options specified for LEAOPT
Option
1
2
Leach Calculation Method
Chemical exchange without solubility limit
Chemical exchange with solubility limit
Annual release fraction
Leaching options, 1 and 2, utilize a dynamic model which
estimate the radionuclide concentration in the trench water based
on chemical exchange.
2-17
-------
The model is developed based on a multi-phase leaching
concept (Hu86b) which simulates a leaching system under field
environment. The model assumes that the flow of infiltration is
concentrated in preference paths and, thereby, forms a finger
flow system. This flow system leads to the transport of
radionuclides in two phases, the convective phase and diffusive
phase. These phases of transport is assumed to take place in
convective zone and diffusive zone respectively. The
radionuclides in the diffusive zone must be transported to the
convective zone first before it can be transported downward
through convective process.
Due to the complexity in the modeling of the multi-phase
leaching concept, a simplified and yet conservative model is
used. The simplified model assumes an idealized steady uniform
leaching model to calculate the radionuclide concentration in the
trench water based on chemical exchange process. A correction
factor is then added to account for the leaching process under
field conditions derived from the multi-phase leaching concept
(Hu86b). The final formula is expressed by:
IT-FAC
DTKd2pM)
(Chemical exchange option) (2-18a)
and
FAC = Min [TINFL/PERMT, 1] (2-18b)
where
FAC = a correction factor to account for the multi-phase
leaching phenomenon experienced in field conditions,
TINFL = annual infiltration rate (m/yr),
PERMT = trench hydraulic conductivity (m/yr),
2-18
-------
= concentration of radionuclide in trench water (Ci/cm3) ,
IT = amount of activity in trench (Ci),
AT = trench area (m2) ,
WT = porosity within trench (unitless),
DT = trench depth (m),
Kd2 = distribution coefficient within waste for radionuclide
(ml/g), and
pw = density of waste material (g/cm3) .
Leaching option 2 uses a solubility factor to estimate the
maximum concentrations of radionuclides in the trench water. The
solubility option may be used when the radionuclide solubility is
low or information concerning Kd values is not available. The
concentration of the radionuclide is estimated by:
= Min
S«NCNV I,
• 1
M DTArW,. + 7.7^1^2Pw J
(Solubility Option) (2-18c)
in which,
S = elemental solubility (g/ml)
M = mass of radionuclide (g/mole)
Nc = ratio (Ci/mole)
Nv = ratio (ml/m3)
Leaching option 3 allows the user to input an average annual
fractional release of the total radionuclide inventory. This
2-19
-------
fraction is applied to each radionuclide and does not consider
either Kd or solubility. Leaching option 3 is normally used for
a solidified waste form. The model calculates the primary
release of radionuclide from the waste form by using a user-
specified constant-fractional leach rate. To accommodate the
hydrodynamic effects, the released radionuclides are then
adsorbed by the waste form according to Equation 2-18a to
calculate the actual rate of release out of the trench. This
calculation accounts for the adsorption effects inside and
outside of the waste form.
Waste containers can inhibit nuclide leaching until they
lose their integrity. The duration for the containers to lose
their integrity, container life, depend on their design,
structural strength, and material. In PRESTO-EPA-POP, the net
radionuclide release is calculated by multiplying the
radionuclide concentration in the trench water by the fractional
container fracture factor (CFF) that is time dependent. The
fraction CFF is set to zero while all of the containers are
intact. Once the containers start to fracture, CFF is assumed to
increase linearly to a maximum value of 1, which represents
failure of all of the containers.
Transport Below Trench
Once radionuclides have been leached out of the waste in the
trench and have migrated through the surrounding trench walls or
bottom, they are transported vertically downward to the aquifer
and then horizontally through the aquifer to a well. The
velocity of radionuclide transport is retarded, relative to the
movement of water, by vertical and horizontal retardation
factors, Rv and RH, as explained below.
The groundwater flow in the vertical reach is assumed to be
saturated or partially saturated. The degree of saturation is
used to calculate the water velocity, Vv and the vertical
retardation factor, Rv. The degree of saturation, SSAT, is
either read in as an input parameter or calculated from the
equation:
ATINFL ° 25
2-20
-------
SSAT = RESAT + (1-RESAT)
PERMV
(2-19a)
where
RESAT = residual moisture content, expressed in a fraction of
total water content when saturated (unitless)
ATINFL = average exfiltration rate (m/yr)
PERMV = vertical saturated hydraulic conductivity (m/yr)
Equation (2-19a) is based on approximate expressions for the
fraction of saturation (Cla78, McW79). The exponent, 0.25, is
generally a function of soil type, but has been assigned a
conservative fixed value for simplicity. The residual moisture
content, RESAT, is an input parameter that is generally identical
to the input parameter Wp of the INFIL submodel. The parameter
ATINFL is the average trench exfiltration rate. When there is no
overflow of trench water, the rate is calculated by the
expression
ATINFL = [PCT2-(PPN+XIRR)+(2-PCT2)-XINFL]-0.5 (2-19b)
where
PCT2 = maximum fraction of trench cap failure (unitless)
PPN = annual precipitation rate (m/yr)
XIRR = annual irrigation rate (m/yr)
XINFL = infiltration rate through the intact trench cap (m/yr)
(calculated by the INFIL subroutine)
Vertical water velocity Vv (m/yr), and the vertical
retardation factor RV (unitless) are calculated as follows:
Vv = ATINFL/(PORV*SSAT)
(2-19c)
2-21
-------
RV = 1 + (BDENS«XKD3)/(PORV«SSAT) (2-19d)
where
BDENS = host formation bulk density (g/cm3)
XKD3 = distribution coefficients for the host formation (ml/g)
PORV = subsurface porosity (unitless)
On the other hand, the horizontal retardation factor, RH, is
calculated as
RH = 1 + (BDENS•XKD4)/PORA (2-19e)
where
XKD4 = distribution coefficient of the aquifer (ml/g)
PORA = aquifer porosity (unitless)
Finally, the vertical horizontal transit time, tv (yr), and
tH (yr), are calculated according to
DVRV DHRH
tv = , tH = (2-20)
Vv VH
where:
Dv = distance from trench to aquifer (m)
DH = length of aquifer flow from trench to well (m)
Vv = vertical water velocity (m/yr)
VH = water velocity in aquifer (m/yr)
and retardation factors, Rv and RH, are as previously defined.
2-22
-------
The breakthrough time, which is the time required for a
radionuclide to travel from the bottom of the trench to the well,
is the sum of the vertical and horizontal transit times. The
time it takes for a radionuclide to migrate through the aquifer
from the well point to the point of release to the basin stream
is also calculated by the model. This transit time is calculated
using the corresponding horizontal distance from the well to the
basin stream.
The transport of radionuclides in the aquifer is evaluated
by employing Hung's groundwater transport model (Hu81, Hu86,
Appendix B). The basic equations for the model, as adopted from
Hung, are:
Q = nQ0(t-RL/V) Exp (-AdRL/V) (2-21)
and
oo
i. 5 (RP/ne3) V* Exp [-Nd9- (P6/4R) (R/6-1)2] d9
n =
I °
Jo
Exp(-RNd)
Exp[P/2 - (P/2) (1 + 4RLXd/PV)1/2]
Exp(-RLAd/V)
where
ri = Hung's correction factor, a correction factor to
compensate for the dispersion effect
R = retardation factor, Rv or RH
P = Peclet number, VvDv/d or VHDH/d
8 = dimensionless time, TV/L
Nd = decay number, XdL/V
2-23
(2-22)
-------
L = flow length, Dv or DH (m)
V = water flow velocity, Vv or VH (m/yr)
t = time of simulation (yr)
d = dispersion coefficient (m2/yr)
Ad = radiological decay constant (yr'1)
T = dummy time variable (yr)
Q = rate of radionuclide transport at distance L from the
source (Ci/yr)
Q0 = rate of radionuclide released at the source (Ci/yr)
To calculate the radionuclide concentration at the well
point, the rate of groundwater flow in the plume of contamination
at the well point is calculated by:
WA = VAPADA[V/2 + 2otan(a/2)DH] (2-23a)
where
WA = the rate of contaminated water flow in the plume at the
well point (m3/yr)
VA = groundwater velocity (m/yr)
PA = porosity of aquifer material (unitless)
DA = thickness of the aquifer (m)
a = constant angle of spread of the contaminant plume in
the aquifer (radian)
AT = trench area (m2)
DH = trench-to-well distance (m)
2-24
-------
The angle "a" is the dispersion angle of a contaminated
plume in the water in an aquifer. This dispersion angle may be
empirically determined (e.g., by field dispersion tests wherein
the angle of dispersion is determined from measurements of
chemical, conductivity, or radioactivity tracers in water from a
series of bore holes downstream across the plume), or it may be
estimated. The use of a dispersion angle is consistent with
published characterizations of the horizontally projected profile
of a chemical contamination front as it moves through an aquifer
(Sy81).
The radionuclide concentration in the well water, Cw
(Ci/m3) , is calculated by
CM = Q/WA (2-23b)
The total water demand, VUf including drinking water, cattle
feed, and crop irrigation, is calculated by
Ą„ = [S.SE-T-W^Li; + UWLH + 1.5E4»LA]Np (2-24)
where
Vu = annual well water demand in liters (I/person-yr)
3.9E7 = 4492 m2 irrigated per person X 8760 hr/yr
Wz = irrigation rate per unit area (l/m2-hr)
f: = fraction of year when irrigating (unitless)
UM = individual annual water consumption (1/person-yr)
LH = fraction of drinking water obtained from well water
1.5E4 = water fed to cattle consumed by humans (1/person-yr)
LA = fraction of cattle feed water obtained from well water
2-25
-------
= size of the population (persons)
= fraction of irrigation water obtained from well water
If the calculated total water demand, Vu, exceeds the flow
rate of the contaminated plume, WA, the concentration of
radionuclides in the pumped out water is recalculated using the
actual volume of pumping to correct for the dilution effect from
the non-contaminated groundwater. Units of V0 are converted to
cubic meters within the code.
The calculated concentrations of radionuclides in well water
are averaged over the length of the simulation and used by the
food chain and human exposure parts of the code for the drinking
water and cattle feed pathways.
Trench Overflow Transport and Stream Contamination
As previously mentioned, water will overflow the trench
onto the soil surface when the maximum depth of standing water is
greater than the trench depth. If this occurs, radionuclides
will be added to the surface inventory of radionuclides deposited
by initial operational spillage. The surface soil will then have
a component adsorbed by the soil with concentration Css (Ci/kg)
and a component of contaminated water in the surface soil of Csw
(Ci/m3) . The material adsorbed by the soil will remain in the
soil and becomes a source term for resuspension and atmospheric
transport (this process is discussed in Section 2.2.2). The
contaminated water in the surface soil is available to enter
nearby surface water bodies via overland flow, or percolate down
to the aquifer.
Radionuclides dissolved in the soil water may either be
transported to the stream by overland flow or to the deep soil
layers by percolation. The amount of each radionuclide added to
the stream is represented by the product of Csw, the radionuclide
concentration in the surface soil water, and the annual volume of
runoff from the contaminated soil surface, WSTREM. The value of
Csw for each radionuclide is calculated by
2-26
-------
1000*IS
Csw = (2-25)
KdlMs + MW2/pM
where
Csw = radionuclide concentration in surface soil water
(Ci/m3) ,
Is = amount of radionuclide on surface (Ci),
Kdl = distribution coefficient for surface soil region
(ml/g),
MS = mass of soil in contaminated region (kg),
MM2 = mass of water in contaminated soil region (kg),
pw = density of water (g/cm3), and
1000 = conversion factors used for K
-------
ps = soil bulk density (g/cm3)
Ws = soil porosity (unitless)
1000 = conversion factor for the mass of soil and water
Water falling on the contaminated soil region may either
evaporate, run-off, or infiltrate. Of the liquid, a certain
fraction of the total precipitation, fr, will enter the stream
annually.
The amount of water that enters the stream from runoff of
the contaminated region is given by
Ws = frPSMSL. (2-28)
The amount of water that enters deep soil layers and eventually
the aquifer is given by
WD = WaSwSL (2-29)
where Wa is the yearly infiltration rate for the farmland.
The annual amount of radionuclides moving from the
contaminated surface soil region to the stream, Rs, is then the
product of Ws and the radionuclide concentration in the surface
soil water CSWI (Equation 2-25) . The amount of each radionuclide
annually entering the deep soil layers from the contaminated
surface soil region is the product of WD and Csw. The concen-
tration of radionuclides in the stream is the quotient of Rs and
the annual flow rate of the stream.
As with water removal from the well, the amount of each
radionuclide removed from the stream is conserved by using
Ir = [3.9E'7»^lfISI + UMSH + 1.5E4«SA] •NP«CRW (2-30)
2-28
-------
where
Ir = annual amount of nuclide removed from stream (Ci)
CRM = radionuclide concentration in stream (Ci/m3)
S1 = fraction of irrigation water obtained from stream
SH = fraction of drinking water obtained from stream
SA = fraction of cattle feed water obtained from stream
Other parameters are the same as defined for
Equation 2-24.
If Ir is larger than the annual input of that nuclide to the
stream, Rs, then the radionuclide concentration in the stream is
recalculated referencing the water volume removed from the stream
rather than the stream flow by
CRW = RS/VU. (2-31)
Mean concentrations of each radionuclide in well water and
stream water are calculated for the appropriate number of
simulation years by dividing the sum of the annual radionuclide
concentrations in the well water and the stream water by the
length of the simulation.
2.2.2 Atmospheric Transport Sources and Pathways
For some sites, atmospheric transport of radionuclides may
be a major transport mechanism. Therefore, careful consideration
is given to obtain an accurate atmospheric transport model. On
the other hand, one of the goals in developing the PRESTO-EPA-POP
is to minimize the complexity of input data. A compromised
solution to achieve these conflicting goals is to employ a
simplified and compact algorithm for the model. A model assuming
the population is concentrated into a single, small community,
and allow the code user to enter an externally computed
population average value, the air concentration, X, to source
strength, Q, ratio. An example of a code which could be used for
2-29
-------
determining this ratio, X/Q, is AIRDOS-EPA (Moo79).
In most cases, the uncertainties in the computed atmospheric
source strength for contaminated areas are larger than the
differences between the internally computed and externally
determined (using a code such as AIRDOS-EPA) X/Q ratios. Use of
an external code has several advantages; the most salient being
that explicit specification of complex population distributions
and the site wind rose removes the possibility of the code user
making errors of judgement in determining population centroid.
Internal Model Capability and Formulation
The atmospheric transport portion of the code will be
discussed in two parts: (a) a description of source strength
computation and (b) a discussion of the calculation of
atmospheric concentration at the residence site of the specified
at-risk population. For most applications, the model is expected
to be applied to a site of known population distribution, and the
user must input geographical and meteorological parameters
characterizing the population site and its relationship to the
low-level waste disposal area. The formulation of atmospheric
transport discussed herein is not intended to automatically
identify regions of high risk; rather, it is formulated to
calculate risk-related parameter values for a particular,
identified site.
Where population health effects are to be determined, the
geometric population centroid specified by the user is the point
for which a 22.5-degree sector average ground level air
concentration is determined. Where the population distribution
subtends from the waste disposal area an angle significantly
greater than 22.5 degrees, the user should run the code
separately for each sub-population. A mean yearly value for the
sector-averaged atmospheric concentration is computed by PRESTO-
EPA-POP and is input to HESTAB for use in computing population
health effects.
The most common approach used for estimating the atmospheric
concentration and deposition of material downwind from its point
of release is the Gaussian plume atmospheric transport model
(S168). This approach is versatile and well documented. We have
chosen to incorporate a Gaussian plume transport code called
2-30
-------
DWNWND (FiSOa) as a module, in subroutine form, in the PRESTO-
EPA-POP code.
User inputs for the atmospheric transport simulation allow
specification of a surface radionuclide concentration at the
waste disposal site. Parameters used here include the initial
surface radionuclide inventory and the chemical exchange
coefficient for surface soils. The portion of radionuclides
sorbed onto soil particles is considered available for transport.
A source strength is computed based either on a time-dependent
(monotonically decreasing) resuspension factor or a process-
dependent mechanical suspension variable. The given LLW site is
described by meteorological variables including:
FM = fraction of the year wind blows toward at-risk
individuals,
H = source height (m),
HL = lid height (m),
S = stability class,
Td = type of dispersion formulation,
Hr = Hosker roughness parameter (m) (about .01 of the actual
physical roughness),
u = wind velocity (m/s),
Vd = deposition velocity (m/s),
Vg = gravitational fall velocity (m/s), and
x = distance from source to receptor (m).
Source Term Characterization
The release rate for atmospheric transport is termed the
source strength. In PRESTO-EPA-POP, the source strength is
directly dependent on the surface soil-sorbed radionuclide
concentrations from operational spillage and trench overflow, CG
2-31
-------
(Ci/m2) . The source strength is the arithmetic sum of two parts:
a time-dependent resuspension factor, Re/ (An75) and a
resuspension rate, Rr, (He80).
First, the wind-driven suspension component is described.
If the time-dependent resuspension factor is defined as
Re = RelExp(Re2T1/2) + Re3 (2-32)
where T is elapsed time (days) and Re has units of inverse
meters, then the atmospheric concentration above the site, CA, is
given by
CA = ReCG (2-33)
and
CG = 1000«CspsSD (2-33a)
Using Anspaugh's values of 1E-4, -0.15, and 1E-9 for Rel,
Re2, and Re3, respectively, the value of Re calculated as above is
probably conservative for humid sites. As additional data from
humid sites become available, model users may wish to update the
equation used for computing Re.
The value of elapsed time appearing in Equation 2-32 is
computed from the start of the simulation. It is, therefore,
correct for the initial surface inventory, but not for
incremental additions thereto, which may occur at later times.
However, when later additions result from trench overflow, they
will likely consist of dissolved material and would likely act as
surface depositions of mobile particulate. It is, therefore,
assumed that a steady-state asymptotic value of Re is for most
sites appropriate for later additions to the surface inventory.
The user wishing to specify a time independent windblown
resuspension factor may do so by setting the values of Rel and Re2
to zero. When this is done, determination of windblown
suspension of all contributions to the surface inventory will be
2-32
-------
treated identically, regardless of time of occurrence.
In the above expression, CA is the atmospheric concentration
of radionuclide immediately above the site at a height of about
one meter (Shi76), for a site of large upwind extent. Large
upwind extent may be interpreted as exceeding the atmospheric
build-up length, given by u HD/Vg/ where u is wind velocity in
m/s, HD is the mixing height (=1 m) , and Vg is the gravitational
fall velocity. The representative site extent used in the
PRESTO-EPA-POP code is the square root of the site area, A (which
is characterized by SLSM) , and a tentative correction fraction,
F. The correction factor is computed using the equation:
F = [V,(SLSw)1/2/uHD] . (2-34)
With the stipulation that the value used for F may not
exceed unity, the source term component (Ci/s) for windblown
suspension is given by:
Qr = CAHDuFA1/2. (2-35)
The second source component results from mechanical
disturbance of site surface soil. Mechanical disturbance occurs
during a user-specified interval. Within this interval, the
fraction of time per year that the disturbance occurs is Fmech.
The source term component for mechanical disturbance is the
resuspension rate, Rr, having units of inverse seconds, as:
Q-nech = CcARrFmech. (2-36)
The net source strength for the site is the sum of these
components:
Q = Qr + Qmech (2-37)
2-33
-------
Transport Formulation
The PRESTO-EPA-POP code uses a Gaussian plume atmospheric
transport model, which is an extension of an equation of the form
(S168)
2nuoyoz
(2-38)
This equation describes Gaussian distribution, where X
represents the radionuclide concentration, Q the source strength,
and H the corrected source release height to be discussed later.
Dispersion parameters, ay and oz/ are the standard deviations of
the plume concentration in the horizontal and vertical
directions, respectively. The aerosol is assumed to be trans-
ported at a wind speed (height-independent), u, to a sampling
position located at surface elevation, z, and transverse
horizontal distance, y, from the plume center. Mass conservation
within the plume is insured by assuming perfect reflection at the
ground surface. This is accomplished by the use of an image
source at an elevation -H, which leads to the presence of two
terms within the braces, and to the factor 1/2. A correction for
plume depletion will be discussed later. Equation 2-38 may be
obtained from any of several reasonable conceptual transport and
dispersion models.
Atmospheric transport at several sites of possible interest
to individuals evaluating consequences of radionuclide transport
has also been considered elsewhere. These sites include Hanford,
Washington (Fi8l, Mi8l), Savannah River, South Carolina (FiSOb),
and Brookhaven, New York (Si66).
Implicit in Equation 2-38 is the assumption that the plume
centerline height is the same as the release height, H. In
practice, the plume may be considered to originate at some
height, H, with respect to the population at risk. Some
2-34
-------
situations, such as the existence of a ridge between the disposal
site and the population centroid, may dictate use of an effective
height greater than H, e.g., the ridge height. The plume thus
has an effective height, Heff) at which the plume may be
considered to originate. This effective value should be used
instead of the actual stack height as the starting point of
Gaussian plume calculations. If the particulate in the effluent
has an average gravitational fall velocity, Vg, the plume
centerline will tilt downward with an angle from the horizontal,
the1 tangent of which is Vg/u. The elevation of the plume
centerline at a distance x downwind is then
H = Heff - xVg/u (2-
39)
for H i 0
and it is this corrected value that is used to compute the
aerosol concentration at a distant point.
Effects of a Stable Air Layer on Transport
The Gaussian plume formulation has been modified for use in
PRESTO-EPA-POP to account for the presence of a stable air layer
at high altitudes. Upward dispersion of the plume subsequent to
release is eventually restricted when the plume encounters an
elevated stable air layer or lid at some height HL. Pasquill has
summarized some reasonable approximations to the modified
vertical concentration profile for various ranges downwind which
are used here (Pa76) . The limiting value of az may be defined as
az(limit) = 2 (HL - H/2)/2.15. (2-40)
This equation follows from setting the ground-level contribution
to the plume from an image source located above the stable air
layer to one-tenth the value of the plume concentration. It is
assumed that the limiting value of az calculated in this manner
2-35
-------
is correct for distances beyond this point. For shorter downwind
distances, where the vertical dispersion coefficient az is less
than az(limit), the Pasquill-Gifford value of oz is used. For
greater downwind distances, where oz is greater than or equal to
oz(limit), the value of az(limit) given in Equation 2-40 is used
instead. The lid height is a user-specified value in the PRESTO-
EPA-POP code. For LLW applications, the source height will
usually be sufficiently low that the influence of HL will be
small. For some sites, however, the influence of an intervening
ridge may necessitate a larger effective source height.
Effects of Plume Depletion
The plume is depleted at ground level during travel as the
particulate are deposited. Both fallout and electrochemical
deposition may be important considerations, and ground cover
characteristics are of major importance. Under certain obvious
conditions, washout is also of importance, but those conditions
have not been included within this model. Fallout is partially
quantified in the Vg term defined earlier. Near ground level the
deposition process is often characterized by a deposition
velocity Vd (Gif62, Mu76a, Mu76b). The deposition rate W is
defined by
W = Vd X, (2-41)
where
X = radionuclide concentration in air (Ci/m3) .
The magnitude of the plume depletion within the downwind
sector may be found by integrating the deposition across the
entire plume. Using Equation 2-38 and setting z = 0, it is found
that
dQ/dx = f VdXdy
2-36
-------
(VdQ/unayoz)Exp[-(y2/2oy2) - (H2/2oz2) ] dx (2.42)
By performing the indicated quadrature across the plume and
further integrating along the longitudinal direction to express
the loss of release agent as a multiplicative factor, it can be
shown (Mi78) that the ratio of the air concentration considering
deposition processes, Xd/ to the air concentration without
regarding deposition, X, is
Fd = Xd/X = Exp{-(2/n)1/2Vd/u f (l/az) Exp [-H2/ (2az2] dx} (2-43)
J 0
Since az is a complicated empirical function of x, Equation 2-43
must be evaluated numerically.
In the PRESTO-EPA-POP applications, the average value of
radionuclide concentration X across a 22.5-degree downwind sector
is the desired quantity. In this case, the trans-sector
integration leads to the value 2.032 in the air concentration
equation (Cu76). This value includes the l/2n factor in Equation
2-38.
In conclusion, assuming that the radionuclide distribution
is that of a Gaussian plume, we may compute the mean radionuclide
concentration, X, at ground level for the 22.5-degree downwind
sector by
X= (2.032FdFwQ/uxoz)Exp[-(H2/20Z2] . (2-44)
The value of H in Equation 2-44 must be an effective source
height. This value is corrected in the model for plume tilt as
in Equation 2-39 and the accompanying discussion. In the code, H
is on the order of 1 m for reasonably flat sites but, in many
other cases, different values should be used to account for local
site characteristics; e.g., for the presence of updrafts.
It has been noted that the choice of plume dispersion
2-37
-------
parameter az is a user option in the PRESTO-EPA-POP code. Choice
of appropriate parameterization depends on site meteorology,
topography, and release conditions. The DWNWND code (FiSOa),
which has been included as part of the model, includes a choice
of eight parameterization schemes for plume dispersion and a
choice of six stability classifications. The most often used
dispersion parameterization scheme for the Gaussian plume is the
Pasquill-Gifford model. This is the approach most appropriate
for the assessment of long-term performance of LLW disposal
sites. Likewise, unless site-specific meteorology dictates
otherwise, the D stability category, denoting a neutral
atmosphere, should be used.
Pasquill (Pa61, Pa74) considered ground-level emission
tracer studies and wind-direction fluctuation data and developed
dispersion parameterizations for six atmospheric stability
classes ranging from A, most unstable, through F, most stable.
Pasquill's values are approximate for ground-level emissions of
low surface roughness (Vo77). These values were devised for
small distances to population (<1 km). The so-called Pasquill-
Gifford form of this parameterization (Hi62) has been tabulated
by Culkowski and Patterson (Cu76), and is used in this model.
2.2.3 Food Chain Calculations
Mean concentrations of radionuclides in air, stream water,
and well water are calculated by using the equations listed in
Sections 2.2.1 and 2.2.2. This section describes how
radionuclides in those environmental media are used to calculate
human internal exposure and potential health effects.
Radionuclides in water may impact humans by internal
exposure, directly from use of drinking water or indirectly from
use of irrigation water used for crops. Radionuclides in air may
impact humans by either external or internal radiological doses.
External doses may result from immersion in a plume of
contaminated air or by exposure to soil surfaces contaminated by
deposition from the plume. Internal doses may result from
inhalation of contaminated air or ingestion of food products
contaminated by deposition from the plume. Dose and health
effects calculations are made by the HESTAB subroutine which is
modified from DARTAB program (Be8l). Radionuclide related input
2-38
-------
to HESTAB consists of the constant concentrations in air (person-
Ci/m3) , constant concentrations on ground surface (person-Ci/m2) ,
constant collective ingestion rate (person-pCi/yr) and constant
collective inhalation rate (person-pCi/yr). Calculation of these
variables follows.
Concentrations of radionuclides in air which affect the
population or an individual are calculated as described in
Section 2.2.2. It is assumed that the mean nuclide
concentrations in air are constant during the total period of the
simulation, as required, for input to HESTAB.
Concentration of each radionuclide on the ground surface,
Qs(PCi/m2) is calculated using
Qs = CSP + CSPO, (2-45)
where
Qs = concentration of radionuclide on the ground surface at
the populated area of interest (pCi/m2)
CSP = radionuclide concentration in the soil used for farming
due to atmospheric deposition (pCi/m2)
CSPO = radionuclide concentration in the soil used for farming
due to irrigation (pCi/m2)
Appropriate unit conversions are made within the code.
The inhalation rate of radionuclides is calculated by
multiplying the generic individual inhalation rate by the
concentration of radionuclides.
Qmh = UaCA, (2-46)
where
Qmh = rate of inhalation exposure (Ci/yr)
2-39
-------
Ua = inhalation rate (m3/yr)
CA = mean ground level radionuclide concentration at a point
of interest (Ci/m3)
The units of Qinh are converted to person-pCi/yr by the population
size for input to the HESTAB subroutine.
The ingestion rate is the input to HESTAB that requires the
most calculation. Ingestion includes intake of drinking water,
beef, milk, and crops. Except for drinking water, all of these
media may be contaminated by either atmospheric processes or by
irrigation.
The atmospheric deposition rate onto food surfaces or soil
that is used in subsequent calculation of radionuclide content in
the food chain is
d = 3.6E15»CAVd, (2-47)
where
d = mean rate of radionuclide deposition onto ground or
plant surfaces (pCi/m2«hr) ,
CA = mean ground-level radionuclide concentration at the
point of interest (Ci/m3) ,
3.6E15 = conversion factor, sec-pCi/hr-Ci, and
Vd = deposition velocity (m/sec).
The following equation estimates the concentration, Cv, of a
given nuclide in and on vegetation at the deposited location
(except for H-3 and C-14):
Cv = d-R[l-Exp(-Xete)]/(Yv\e) + (B«CSP/P)Exp(-Adth) (2-
48)
2-40
-------
where,
Cv = the radionuclide concentration in pCi/kg,
d = mean rate of radionuclide deposition onto ground or
plant surfaces (pCi/m2»hr) ,
R = the fraction of deposited activity retained on crops
(unitless),
Ae = effective removal rate constant for the radionuclide
from crops (hr'1) , which is the sum of the radioactive
decay constant and the removal rate constant from
weathering, Aw,
te = the time period that crops are exposed to contamination
during the growing season (hr),
Yv = the agricultural productivity or yield [kg (wet
weight) /m2] ,
B = the radionuclide concentration factor for uptake from
soil by edible parts of crops, [pCi/kg (dry weight) per
pCi/kg dry soil],
CSP = soil radionuclide concentration updated yearly
(pCi/m2) ,
P = the effective surface density for topsoil [kg(dry
soil) /m2] , and
th = time interval between harvest and consumption of the
food (hr).
In the above equation, the value of CSP is calculated by:
CSP = (CSPL + d-At)Exp[- (Xd + As)At]
where
CSP = soil radionuclide concentration for this year (pCi/m2) ,
2-41
-------
CSPL = soil radionuclide concentration for last year (pCi/m2) ,
d = mean rate of radionuclide deposition (pCi/m2-yr) ,
Xd = radioactive decay constant (yr'1) ,
Xg = rate constant for contaminant removal (yr'1) ,
At = time increment, equal to one year in PRESTO model,
If farming is performed on the trench site, then the soil
radionuclide concentration is calculated as:
SOCON = 1E12»SD(CSWWS + 1000«Cssps)
where
SOCON = soil radionuclide concentration (pCi/m2) ,
SD = depth of contaminated surface region (m),
Csw = radionuclide concentration in interstitial water of
contaminated surface region (Ci/m3) ,
Ws = porosity of surface soil (unitless),
Css = radionuclide concentration in soil of contaminated
surface region (Ci/kg) ,
ps = bulk density of surface soil (g/cm3) ,
1E12 = pCi/Ci, and
1000 = (kg/g)»(cm3/m3) .
The rate constant for contaminant removal from the soil, Xg,
is estimated using
Xs = , (2-49)
(0.15) (8760) {(1 + psKd)/Ws}
2-42
-------
where
Xg = removal rate coefficient (hr'1) ,
rs = watershed infiltration (m/yr),
pg = soil bulk density (g/cm3) ,
Ka = distribution coefficient (ml/g),
Ws = porosity (unitless),
0.15= depth of soil layer (m) , and
8760= hr/yr.
Equation 2-48 is used to estimate radionuclide
concentrations in produce and leafy vegetables consumed by humans
and in forage (pasture grass or stored feed) consumed by dairy
cows, beef cattle, or goats.
The concentration of each radionuclide in animal forage is
calculated by use of the equation
Cf = fpfsCp + (l - fpfJC., (2-
50)
where
CŁ = the radionuclide concentration in the animal's feed
(PCi/kg),
Cp = the radionuclide concentration on pasture grass
(pCi/kg) calculated using Equation 2-48 with th = 0,
Cs = the radionuclide concentration in stored feeds in
pCi/kg, calculated using Equation 2-48 with th = 2160
hr or 90 days,
fp = the fraction of the year that animals graze on pasture
(unitless),
2-43
-------
fs = the fraction of daily feed that is pasture grass when
the animals graze on pasture (unitless),
The concentration of each radionuclide in milk is estimated as:
Cm = FnAQj-Expf-Aatf) (2-51)
where
Cm = the radionuclide concentration per liter in milk
(pCi/1),
Cf = the radionuclide concentration in the animal's feed
(pCi/kg) ,
Fm = the average fraction of the animal's daily intake of a
given radionuclide which appears in each liter of milk
(d/1),
QŁ = the amount of feed consumed by the animal per day (wet
kg/d) ,
tŁ = the average transport time of the activity from the
feed into the milk and to the receptor (hr) , and
Xd = the radiological decay constant (hr'1) .
The radionuclide concentration in meat from atmospheric
deposition depends, as with milk, on the amount of feed consumed
and its level of contamination. The radionuclide concentration
in meat is estimated using
Cf = FfCŁQf»Exp(-Adts)
(2-52)
where:
CŁ = the nuclide concentration in animal flesh (pCi/kg),
2-44
-------
Ff = the fraction of the animal's daily intake of a given
radionuclide which appears in each kilogram of flesh
(d/kg),
Cf = the concentration of radionuclide in the animal's feed
(PCi/kg),
Qf = the amount of feed consumed by the animal per day
(kg/d), and
ts = the average time from slaughter to consumption (hr).
Concentrations of radionuclides in foodstuffs that result
from spray irrigation with contaminated water are estimated using
essentially the same equations as for atmospheric deposition with
the following differences: the concentration in vegetation, Cv,
is estimated using Equation 2-48, but a different value of the
retention fraction, R, is used. For irrigation, the second term
of Equation 2-48 is modified by a factor of fz, the fraction of
the year during which irrigation occurs, and the te in the
exponent becomes twl equivalent to fl in hours. For irrigation
calculations, the deposition rate, d, in Equation 2-48 becomes
the irrigation rate, Ir, expressed as:
Ir = Cw Wx (2-53)
where
Ir = radionuclide application rate (pCi/m2 hr) ,
Cw = radionuclide concentration in irrigation water (pCi/1),
and
Wz = irrigation rate (l/m2-hr) .
The concentration in water, CB, is an average of well and stream
water weighted by the respective amounts of each that are used.
Another modification introduced for irrigation calculations
is related to the radionuclide concentration in milk and meat
2-45
-------
where the animal's intake of water was added to Equation 2-51 and
2-52, respectively. This becomes:
Cm = Fra(CfQf + CwQw)Exp(-Xdtf) (2-54)
CF = Ff(CŁQf + CwQw)Exp(-Xdtg) (2-55)
where:
Qw = the amount of water consumed by the animal each day
(1/d)
Once radionuclide concentrations in all the various
foodstuffs are calculated, the annual ingestion rate for each
radionuclide is estimated by
Qing = Qv + Qrulk + Qmeat + Qw
(2-56)
where the variables represent individual annual intakes of a
given radionuclide via total ingestion, Qing, and ingestion of
vegetation, Qv, milk, Qmilk, meat, Qmeac, and drinking water, Qw,
respectively, in pCi/yr. The annual intakes via each type of
food, Qv for instance, are calculated as
Qv = (CVI + CVA)UV (2-57)
where
Qv = annual radionuclide intake from vegetation (pCi/yr),
CVI = radionuclide concentration in vegetation from
irrigation (pCi/kg),
CvA = radionuclide concentration in vegetation from
atmospheric deposition (pCi/kg), and
2-46
-------
Uv = individual annual intake of vegetation (kg/yr).
To satisfy the input requirements for HESTAB, the annual
individual intakes are multiplied by the size of the population
to calculate the collective ingestion annually.
As mentioned earlier, Equations 2-47 through 2-55 do not
apply directly to calculations of concentrations of H-3 or C-14
in foodstuffs. For application of tritium in irrigation water,
it is assumed that the transfer factor for the concentration in
all vegetation, Cv, from the tritium concentration in the
irrigation water is 1 when the units of Cv and CM are in pCi/kg
and pCi/1, respectively, then
Cv = 1-CW (2-58)
where Cv and Cw are in pCi/kg and pCi/1, respectively. In the
same manner, the concentration of H-3 in animal's feed, Cf, is
also equal to Cw. Then, from Equations 2-54 and 2-55, the
concentration of tritium in animal's milk and meat can be written
as:
Cm = FmCw(QE + QJ (2-59)
CF = FfCw(Qf + QJ (2-60)
where
Cm = concentration of tritium in milk (pCi/1),
Fm = fraction of the animal's daily intake of H-3 that
appears in each liter of milk (days/1),
Cw = H-3 concentration in animal drinking water (pCi/1),
Qf = animal's daily intake of forage (kg/d),
Qw = cow's daily intake of water (1/d),
2-47
-------
CF = concentration of tritium in animal meat (pCi/kg), and
Ff = fraction of the animal's daily intake of H-3 that
appears in each kg of meat (d/kg).
The exponential term is neglected due to the relatively long
half-life of tritium as compared to transit times in the food
chain.
The root uptake of C-14 from irrigation water is considered
negligible and, therefore, has been set equal to zero.
For vegetation contaminated by atmospheric deposition of
tritium, H-3 concentrations are calculated by
Cv = (CA/h) (0.75) (0.5) (1E15) (2-61)
where
Cv = tritium concentration in vegetation (pCi/kg),
CA = concentration of H-3 in air (Ci/m3) ,
h = absolute humidity of the atmosphere (g/m3) ,
0.75 = ratio of H-3 concentration in plant water to that
in atmospheric water,
0.5 = ratio of H-3 concentration in atmospheric water to
total H-3 concentration in atmosphere, and
1E15 = (1E12 pCi/Ci)x(1000 g/kg).
The mean ground-level air concentration of H-3, CA, is calculated
using the equations in Section 2.2.2.
For C-14, the concentration in vegetation is calculated
assuming that the ratio of C-14 to be the natural carbon in
vegetation is the same as that ratio in the surrounding
atmosphere. The concentration of C-14 is given by
2-48
-------
Cv = (CA/0.16)(0.11)(1E15) (2-62)
where
Cv = C-14 concentration in vegetation (pCi/kg),
CA = mean ground-level concentration of C-14 in air (Ci/m3) ,
also calculated from equations given in Section 2.1.2
r = ratio of the total release time of C-14 to the total
annual time during which photosynthesis occurs, r s 1,
0.11 = fraction of the plant mass that is natural carbon,
0.16 = concentration of natural carbon in the atmosphere
(g/m3), and
1E15 = (1E12 pCi/Ci)x(1000 g/kg).
2.2.4 Health Effects Estimates
The health effects or individual risk of premature death for
an individual residing at location k for the 1th cancer, ith
radionuclide, and jth exposure pathway is given by:
R1Dl(k) = 10-5K:-E1D(k) -RF13l/P(k) (2-
63)
where K3 is a numerical factor used to reconcile the units of
E13 (k) and RFl3l; EID (k) is the exposure rate for the ith
radionuclide by jth pathway; RFi:|1 is the risk factor for the 1th
cancer due to an unit exposure of ith radionuclide through the
jth pathway; and P(k) is the exposed population at kth location.
The total individual risk from the exposure of all nuclides
through all pathways can, therefore, be written as:
R(k) = 10'5-S Kj-S E^fkjSRF^/Pfk) (2-
2-49
-------
64)
The collective health effects are expressed in the health
effects rate. Therefore the total equivalent fatal cancer rate
in an exposed population is calculated by:
HE = (lO-VT.)-S Vsk-iiEiD(]c)-SRFiji/P(]0 (2_
65)
in which, Te is mean individual life expectancy (70.7 years).
Readers desiring a complete discussion of the development of
the health effects should consult with DARTAB documentation
report (Be81, pp. 5-10) and refer the risk and risk conversion
factors used in the HESTAB submodel to the cancer risks
estimation report (EPA94).
2.2.5 Daughter Nuclide In-Growth Effect Correction
The previous version of the PRESTO-EPA-POP model calculates
the health impacts resulting from only the parent nuclide while
ignoring the health impacts contributed from its progeny. This
simplification may, in some cases, cause significant error in the
results of the risk assessment.
Since the existing model was designed to evaluate health
impacts without progeny effects, one of the simplest approaches
in integrating the progeny effects into the existing model is to
introduce a progeny effect correction factor. This correction
factor can then be used to adjust the results obtained from the
existing model to account for the progeny effects.
In order to avoid the complex model, a crude assumption is
imposed upon the progeny effect correction factor analysis. The
model assumes that the sorption characteristics of the parent
nuclide and its progeny are identical throughout the processes of
leaching and transport through the geosphere. This assumption
seems to be unrealistic; but the error induced from this crude
assumption is not excessive and, in most cases, is on the
2-50
-------
conservative side. On the other hand, this assumption is adopted
in most of the screening risk assessment models.
When the above assumption is imposed, the ratio of the
activities between progeny and parent nuclides in a designated
moving control volume at any given time can be calculated from
the Bateman equation. This ratio is then used to calculate the
correction factor to account for progeny in-growth effects.
Decay Chains
For the purpose of assessing the health impacts from the
disposal of LLW and NORM waste, the following simplified decay
chains are selected for incorporation into the PRESTO-EPA model
1. Am-243 - Pu-239 • U-235
2. Cm-244 Pu-240 > U-236 —- Th-232
3. Pu-238 > U-234 —- Th-230 Ra-226 • Pb-210
4. Pu-241 Am-241 Np-237
5. Pu-242 —- U-238 U-234 —- Th-230 Ra-226 • Pb-210
The decay chains depicted above assume that those progeny
not shown in these chains can be ignored for the analysis. The
error introduced from this simplification is considered to be
insignificant for an application to a screening model.
Altogether, 13 parent nuclides are considered and built into
the model for calculating their progeny effects. They are Am-
243, Pu-239, Cm-244, Pu-240, U-236, Pu-238, U-234, Th-230, Ra-
226, Pu-241, Am-241, Pu-242, and U-238. The model evaluates the
progeny in-growth effects up to the fourth member of the chains
shown above; the effects from the fifth and higher members are
neglected. Using Pu-242 as an example, the analysis calculates
the potential health effects induced from U-238, U-234, and Th-
230 only. All other progenies are ignored.
2-51
-------
The derivation of the correction factors representing the
progeny-ingrowth effects for the second, third, and fourth decay
chain members are derived and attached in Appendix C. The
results are summarized as follows:
'2 2 CF
1 EXP(-(X -X ) t)
X-j •*• ? 1
..
X -XI X -X
2 12
2 A ' (2-66
XP(-(X2-X1)t)
(X2-X3) (XrX3)
-X.)t)
' '2-67;
I CF4
n. = x,x,x. —-
'4 234 f,™
•\,
^ (X4-X2) (X3-X2) (\
EXP(-(X-X.)t) EXP(-(X-X.)t)
+ — + 1 (2-68)
(X -X ) (X -X ) (X -X ) X -X ) (X -X ) (X -X )
where
ri = the correction factor relative to the parent nuclide,
X = the radionuclide decay constant,
CF = the health effect conversion factor, and
2,3,4 = the subscripts respectively for the second, third, and
fourth decay chain members.
The combined progeny effects correction factor used in the
model is the sum of all correction factors, that is:
2-52
-------
= 1 + n2 + n3 + ri4 (2-68)
Since the combined health effects resulting from the intake
of a parent nuclide can be expressed as:
AHEC = AHEi + AHE2 + AHE3 +AHE4
or
AHEC = Qi • I • CFi • At + Q2 • I • CF2 • At + Q3 • I • CF3 • At
+ Q4-I-CF4-At (2-69)
which yields:
AHEC = I-CFi-Q^t) «ri(t)«At (2-70)
where HEC is the combined parent and progeny health effects and I
is the intake factor.
Therefore, the cumulative health effects from the decay
chain for a period of analysis can be written as:
HEC = I'CF^I TQ^T\-dt (2-71)
where T denotes the duration of the health effects analysis.
Equation 2-71 implies that the combined health effects for a
four-member decay chain can be calculated from the integration of
the product of parent-nuclide activity in the control volume and
its combined correction factor over the duration of the health-
effect analysis.
The model involves the evaluation of the cumulative health
effects resulting from the consumption of the radionuclide
contaminated water in the environmental receptors. The
radionuclide concentration in an environmental receptor is
2-53
-------
calculated annually and its average value is calculated at the
end of the yearly loop analysis. The average human exposure rate
and its subsequent health effects are calculated from this
average value. The integration of the progeny in-growth effects
simply involves the modification of the average concentration in
a similar manner as expressed in equation 2-71 as:
C. = d/T) frc(t)-n(t)-dt (2-72)
ave Jo
After the average radionuclide concentration in the
environmental receptor is calculated, the health effects for the
local population are calculated through the existing biological
and human exposure pathways model.
The health effects in the downstream basin population are
calculated from the product of the cumulative release of
radioactivity and the health effects conversion factor for the
regional basin population (Section 2.3). In integrating the
daughter nuclide in-growth effect into the health effect
assessment, the released parent nuclide activity should be
corrected annually. The correction of the cumulative
radionuclide release is calculated by:
QT=fTQl(t)-r\(t)-dt (2-73)
where QT denotes the corrected cumulative radionuclide release.
After the activity of the parent nuclide released to the
downstream basin is corrected for daughter nuclide in-growth
effects, the total health effects for the downstream basin
population are calculated by multiplying corrected cumulative
radionuclide release with the precalculated conversion factor for
the parent nuclide. The calculation of the conversion factors for
the regional basin population is discussed in next section.
2.3 HEALTH EFFECTS INDUCED IN THE REGIONAL BASIN POPULATION
2-54
-------
The PRESTO-EPA-POP model estimates the potential cumulative
health effects induced in the population of a regional basin
downstream from the disposal site for a period of 10,000 years
after site closure. In order to reduce the time of computation,
the analysis is divided into two parts: the primary analysis and
the basin analysis. The primary analysis simulates the health
effects to the local community for the first 1,000 years and the
basin analysis simulates the cumulative release of the residual
radionuclides as defined later for 10,000 years. The cumulative
health effects are then obtained by multiplying the cumulative
residual nuclides with their conversion factors.
The residual radionuclides include those radionuclides not
consumed by the local community during the primary analysis and
those radionuclides leaving the disposal site and entering the
regional basin during the basin analysis. The total health
effects are then calculated from the sum of the health effects
obtained from the primary analysis and the regional basin
analysis. Figure 2-5 shows the concepts of primary and basin
analyses.
The regional basin analysis assumes that all of the
communities located in a regional water basin downstream from the
disposal site, including the community analyzed in the primary
analysis, can be combined into a single composite community. The
transport of radionuclides from the disposal site, through the
hydrologic pathway, continues as described for the primary
analysis. The atmospheric transport pathway is not included,
since it is assumed that the health effects to a more distant
regional basin from this pathway will be negligible.
Instead of performing lengthy food chain simulations and
health effects analyses for 10,000 years, the model calculates the
impact on the basin based on the "residual radionuclides" released
downstream. The radionuclides considered are those that enter the
aquifer through the trench bottom and those enter the regional
stream by way of runoff.
In order to determine the potential health effects induced in
the regional basin population, the residual radionuclide activity
released into the regional basin is multiplied by a conversion
factor precalculated for each radionuclide within PRESTO-EPA-POP
code. The conversion factors, which are nuclide dependent, are
2-55
-------
based on local water use characteristics and the hydrologic
pathway.
YEARS 1 - 1.000
BASM RESIDUAL RADIOACTIVITY:
B(co = (A - W) + (S - Y)
REGIONAL BASM HEALTH EFFECTS:
HE = BxHECF
YEARS 1,001 - 10.0OO
BASM RESIDUAL RADIOACTIVITY:
BJCO = D + S
REGIONAL BASH HEALTH EFFECTS:
HE = BxHECF
Figure 2-5. Regional Basin Health Effects Analyses
2.3.1 Calculations of Regional Basin Health Effects
The code uses health effects conversion factors (see Section
2.3.2) to calculate the potential health effects induced in the
regional basin population from the cumulative activity of residual
radionuclides released to the regional basin. Once the
radionuclides arrive at the basin stream, they are released to
the basin within the same year of arrival. Radionuclides not used
by the regional basin community are assumed to travel to the ocean
where they induce no health effects.
Releases of radionuclides into the regional basin can be
simulated for up to 10,000 years. The annual nuclide releases
2-56
-------
into the regional basin are collected in the model in 10 periods
of 1,000 years each. The annual releases of each nuclide from
the surface runoff and from the aquifer to the regional basin
during the first millennium are collected in the array variable
QDWSB. Nuclides that leave the bottom of the trench during the
first millennium and arrive at the well beyond year 1000 are not
neglected; they are also considered in the yearly loop.
In simulating the cumulative release of radionuclide through
surface water pathway, the radionuclide concentrations in surface
soil and surface water are calculated first according to Equations
(2-25) and (2-26) . These concentrations change from year to year
as a result of wind resuspension, surface water runoff, trench
water overflow, and the seepage of water from surface soil to the
aquifer.
The amount of radionuclides released from the surface soil to
the surrounding surface streams is calculated using the current
year surface water nuclide concentration, Cw (Ci/m3) ,- the area of
the disposal site, S^ (m2) ; the annual precipitation rate, Pa
(m/yr); the current year's amount of trench water overflow, V0
(m3/yr) ; and a transfer factor, fr as follows:
Ws = f^P.-S^Si + V0) (2-74)
SSTREM = WS»CW (2-75)
where Ws (m3/yr) is the amount of water that enters the
surrounding streams from runoff and trench overflow during the
current year of simulation, and SSTREM (Ci/yr) is the amount of
nuclides going along with that volume of water. The surrounding
streams in turn will transport the nuclides to the regional basin
stream within the same current year of simulation.
The net amount released into the regional basin, SSTREM(N),
is calculated by subtracting the amount of nuclides being removed
from the nearby stream(s) for consumption by the local population.
The calculation is accomplished by using the stream flow rate,
STFLOW; the hypothetical volume of water withdrawn from the
stream, VOLUSS; and the stream water concentration, STCON(N). The
2-57
-------
nuclide release into the basin each year for the first millennium
is:
(STFLOW - VOLUSS) STCON(N) if VOLUSS < STFLOW
(2-76)
. 0 if VOLUSS >. STFLOW
In calculating the cumulative release of residual
radionuclide from the aquifer to the basin, the annual transport
of radionuclides are subtracted for the amount being pumped out
for local population consumption first. This subtraction is
perform only during the period of first millennium analysis. This
subtraction is not performed after the first millennium of
analysis. In calculating the cumulative release of radionuclides
into the regional basin, it is necessary to evaluate additional
radionuclide transit times, as well as Hung's correction factors,
for the reach from the well to the stream. The user can also
control the percentage of well water that flows to the basin
stream by specifying the input parameter CPRJ as the fraction of
groundwater that bypasses the basin stream.
The total release of radionuclide, QLBTTH, into the basin is
the sum the releases from surface water and groundwater pathways
over 10,000 years; i.e.,
10
QLBTTH = QDWSB + QLB(J)
(2-77) J=2
where QDWSB and QLB(j) are the total radionuclide released into
the regional basin in the first and jth millennium, respectively.
The population health effects in the regional basin due to
the release of residual radionuclides to the basin are calculated
by multiplying the total release of the radionuclide into the
regional basin by a health effect conversion factor; i.e.,
HE = QLBTTH-HECF (2-78)
2-58
-------
The health effects conversion factors, which are used to
determine the health effects to the regional basin population from
residual radionuclides, are model input values and are
precalculated by using PRESTO-EPA-POP as a tool. The methodology
for calculating these factors is discussed in the following
section (Section 2.3.2).
The regional basin health effects and the genetic effects for
each nuclide over the entire 10,000 years of analysis can now be
calculated by summing up the effects for over 10,000 years,
respectively as follows:
(Basin Health Effects)! = [(Residual nuclide, 1st 1,000
years)1
+ (Residual nuclide, last 9,000 years)J •HECF1
(2-79)
(Basin Genetic Effects)i = [(Residual nuclide, 1st 1000
years)! + (Residual nuclide, last 9,000 years)J•GECFl
(2-80)
The total regional basin health effects and genetic effects
resulting from all basin residual nuclides are calculated by
summing the effects over all nuclides as follows:
N
Total Basin Health Effects = 2^ (Basin Health Effects)!
N
Total Basin Genetic Effects = Ł-> (Basin Genetic effects) L
2-59
-------
2.3.2 Conversion Factors for Regional Basin Health Effects
The health effect and genetic effect conversion factors are
used to calculate the impacts of residual radioactivity entering a
regional water basin. The conversion factors, which are nuclide
specific, are made up of two components, one is calculated from
the terrestrial pathway (HECFtl) and the other from the aquatic
pathway (HECFfl) . Separate conversion factor values are
calculated for health effects and for genetic effects. The
methodology discussed below is applicable to the calculation of
both cancer effect and genetic effect conversion factors.
(1) Terrestrial Pathway;
The nuclide-specific health effects conversion factors for
the terrestrial pathway (HECFtl) are calculated in two steps using
the results from PRESTO-EPA-POP analyses for the local population.
In the first step, the health effects to the local population
resulting from the withdrawal of a unit curie of a specific
nuclide from the local well or stream are determined.
The second step involves the calculation of the fraction of
activity discharged into the basin being withdrawn for consumption
by regional basin population. The HECFtl is then determined by
multiplying the fraction of activity withdrawn, with its health
effect per curie conversion factor, that is:
HECFtl = HE/Ci1 x f (2-81)
where:
HECFtl = the terrestrial HECF for radionuclide i;
HE/Cij. = the health effects to the local population per unit
curie of radionuclide i withdrawn from the local
well or stream; and
f = the fraction of activity withdrawn from the basin
river per unit activity released to the regional
basin.
2-60
-------
The fraction of activity withdrawn by the regional basin
population is calculated based on the local population water usage
and a standard ratio of river flow to population. The per capita
water use (including the water for drinking, cattle feed, and
irrigation) for the local population is calculated taken from
appropriate PRESTO-EPA model inputs. Assuming that the per capita
regional basin water use and the ratio of population to river flow
in the regional basin are constants, then the fraction of activity
that will be withdrawn by the regional basin communities can be
calculated by:
= (C7/P)
(0/P)
(2-82)
where:
f = fraction of activity withdrawn from the basin river per
unit activity released to the regional basin;
(U/P) = per capita water usage (m3/person-yr) ; and
(Q/P) = ratio of river flow to population, 3,000 m3/person-yr
(EPA85).
The per capita water consumption is calculated from the
individual water consumption, local irrigation requirement, and
the cattle feed demand (Equation 2-83). For regions where
multiple water sources are used, fractional correction factors are
applied. For example, a portion of the requirement for the
irrigation water may be met by using a well or stream, while the
remainder may be withdrawn from a farm pond with no contamination.
This is handled by including "switches" in the water consumption
equation. Thus if half of the irrigation water at a given site is
withdrawn from a stream while the rest is gathered from
precipitation-fed farm ponds, the arrogation pathway switch will
equal 0.5. The per capita water consumption as built in the
PRESTO-EPA-POP is expressed by:
U = [3.9xl07W3flL1 + UwLh + 1.5xl04L.] (2-83)
2-61
-------
where
U = per capita water consumption (1/person-yr),
3.9xl07 = 4492 m2 irrigated land per person x 8760 hr/yr,
VI1 = irrigation rate (l/m2-yr) ,
fi = fraction of year when irrigating,
L! = irrigating pathway switch,
Uu = individual water consumption per year (1/person-yr),
Lh = human pathway switch,
1.5xl04 = annual water fed to cattle consumed by humans
(1/person-yr),
La = animal pathway switch, and
Np = size of population,
In calculating the health effects resulting from pumping the
contaminated water from groundwater or surface water, the air
pathway sources should be shut off by setting radionuclide
spillage equal to zero. In addition, no on-site farming or
basement exposures are included. Therefore, the health effects in
the exposed population are due to the consumption of the
contaminated water only.
When the local per capita water consumption is divided by a
standard ratio of river flow to population, the fraction of the
regional basin radioactivity that will be withdrawn by the
regional basin community is determined. This calculation is based
on two assumptions: the local water usage is comparable to
regional basin water consumption, and the national average ratio
of river flow to population is applicable to the regional basin.
Studies show that while regional basin population and river flow
vary widely, the ratio of the river flow to the population remains
relatively constant (EPA85).
2-62
-------
As noted previously, the fraction of nuclides that are not
pumped out by the regional basin community are assumed to enter
the ocean, which acts as a nuclide sink. The health effects
resulting from these activities collected in the ocean are assumed
to be negligible.
(2) Fish Pathway:
One pathway that was viewed as negligible for the local
population but is considered in calculating regional basin health
effects, is that of contaminated fish ingestion. A separate
HECFfl for fish is determined based on the following equation:
HECFfl = (P/Q) x Bfl x Uf x (D/C)i (2-
84)
where:
HECFfl = health effects conversion factor from consumption
of fish, per curie of radionuclide i released to
the regional basin,
(P/Q) = river-flow-to-population ratio (person-yr/3,000 m3)
(EPA85),
Bfl = fish bio-accumulation factor (Ci/kg-fish per Ci/1 of
radionuclide i in water) (NAS71),
Uf = annual fish consumption rate (6.9 kg/person-yr) (Ru80),
and
(D/C)I = conversion factor for health effects per curie of
nuclide i ingested, obtained from HESTAB data file.
(3) Basin Health Effects Conversion Factor
The conversion factors for regional basin health effects can
now be calculated from sum of the conversion factor from
terrestrial pathway and the conversion factor from the fish
pathway. Thus, the nuclide-specific regional basin HECFi can be
expressed as:
2-63
-------
HECF1 = HECFtl + HECFfl (2-85)
The same methodology discussed above is also used for the
calculation of the genetic effects conversion factors. The only
differences are that the genetic effects per unit curie are used
in place of health effects per curie in Equation 2-81, and that
the genetic effects conversion factor is used in place of the
health effects conversion factors in Equation 2-84.
2.4 DEVELOPMENT OF PRESTO-EPA-POP CODE
2.4.1 Model Structure
The mainframe version of the PRESTO-EPA-POP code was written
in FORTRAN VII for an IBM 3081 and requires 850K bytes of memory.
It is designed to process up to 40 nuclides and up to 10,000 years
of simulation period. The subroutine structure of the code is
shown in Figure 2-6.
There are three classes of submodels: unit response,
scheduled event, and bookkeeping submodels. Unit response
submodels simulate processes such as rainwater infiltration
through the intact portion of the trench cap, erosion of soil
overburden from the trench cover, and atmospheric transport. Such
submodels are usually accessed only once during a model run and
generate parameters and rates used elsewhere in the simulation.
Scheduled-event submodels estimate the characteristics of
events such as the percentage of trench cap failure, while
bookkeeping submodels determine the water balance in the trench
and radionuclide concentrations in the trench outflow and the
aquifer. Output from the bookkeeping submodels is iterated
annually over the simulation period. Risk evaluation bookkeeping
submodels accept the cumulative or mean output from the transport
portion of the code and generate doses based on a life-table
approach.
2.4.2 Subroutine Description
2-64
-------
An alphabetical listing and description of the subroutines
and main program found in PRESTO-EPA-POP are given below.
MAIN - This routine is the main calling program of PRESTO-
EPA-POP and defines the most commonly used variables of the code,
specifies dimension and common areas, and initializes variables
and input control parameters. The input and output subroutines,
SOURCE and OUT, are called directly by MAIN (Figure 2-6), as are
the unit response model subroutines AIRTRM and ERORF. MAIN also
calculates: the vertical water velocity; retardation factors;
vertical, horizontal and total transit times in groundwater (the
transfers from trench to vertical soil column to aquifer in Figure
2-1); and the basement exposure correction factor (Section 2.2.2).
The decay dispersion correction factor, DDETA (Hu81), is
calculated for each radionuclide (factor DDETA adjusts the
activity output of the aquifer for the combined interactions of
longitudinal dispersion and radioactive decay). QUANC8, which is
based on an eight-panel Newton-Cotes rule, performs the
integration necessary to obtain the correction factor.
MAIN calls the bookkeeping subroutines to calculate
quantities associated with trench water balance, trench cap
status, changes in land use and basement occupancy. Other
subroutines called by MAIN compute the amount of leaching from the
trench, transport of soluble surface components, atmospheric
concentrations, and well concentrations. In addition, aquifer
2-65
-------
2-66
-------
Figure 2-6. PRESTO-EPA-POP Subroutine Structure
volume, hypothetical radionuclide withdrawal from the well, and
material balances for water in the aquifer are calculated in MAIN.
Food-chain submodels called from MAIN to calculate
radionuclide concentrations in food due to atmospheric deposition,
water irrigation, and cattle feed. These subroutines are IRRIG,
FOOD, HUMEX, CV, COV, IRRIGA, FOODA, HUMEXA, CVA, and COVA.
Finally, HESTAB submodel which creates tables of predicted health
effects from radioactive effluent is called from MAIN.
The annual simulation loop and the radionuclide loop are
executed a selected number of times. During a model run, MAIN may
access any or all of the subroutines or functions which are listed
below in alphabetical order.
AIRTRM - This subroutine is the main calling program for the
atmospheric transport submodel. AIRTRM calculates sector-averaged
(22.5 degree) atmospheric exposures normalized to the source
strength. AIRTRM and all its supporting subroutines are
adaptations of the interactive Gaussian plume atmospheric model,
DWNWND (FiSOa). AIRTRM also calculates the deposition rate onto
surfaces per unit source strength. To make these calculations,
AIRTRM accesses four other subroutines: SIGMAZ, DPLT, YLAG, and
SIMPUN, and utilizes a number of user-input parameters including
source height, lid height, stability class, type of stability
class formulation, Hosker roughness parameter, wind velocity,
deposition velocity, gravitational fall velocity, and source to
receptor distance. The normalized atmospheric exposures are
returned to MAIN and are used in later dose and risk calculations.
CAP - This function calculates and returns to both MAIN and
TRENCH the fraction of the trench cap that has failed. Cap
failure may be either partial or total. Total failure may be
caused by erosion of all overburden as calculated by ERORF.
Partial failure indicates that a portion of the cap has been
completely removed; the remainder of the cap is still subject to
erosion. Partial failure may be simulated, by user input of the
end points of a linear function, to selectively remove all
overburden from a fraction of the trench.
COV. COVA - These functions are called by subroutine IRRIG
2-67
-------
and IRRIGA to calculate radionuclide concentrations in vegetables,
milk, and meat that may be contaminated by irrigation. The
radionuclide concentrations in food depend on such quantities as
the agricultural productivity of vegetation, the period of
irrigation annually, the storage delay period between harvest and
use for pasture grass, feed, leafy vegetables and produce, and the
radionuclide decay constant.
CV. CVA - These functions are utilized by subroutines FOOD
and FOODA to calculate radionuclide concentrations in pasture
grass and stored feed consumed by animals and in leafy vegetables
and produce consumed by humans. CV is essentially the same as the
function COV, except that CV is used for atmospherically deposited
radionuclides and COV accounts for radionuclides deposited by
spray irrigation. Pertinent input data include agricultural
productivity, fraction of the year vegetation is exposed to
depositing radionuclides, and the delay time between harvest and
consumption for stored feed, pasture grass, leafy vegetables, and
produce.
DARTAB/HESTAB - The original DARTAB code is a self-contained
program which combines radionuclide environmental exposure data
with dosimetric and health effects data to create tables of
predicted impacts of radioactive effluent. DARTAB has 11
subroutines and contains over 3,000 FORTRAN source statements.
DARTAB subroutines are RDSTOR, FACOUT, CHLOC, PREPDR, PREPRF,
PREPHR, MULT, DRTAB, ORGFAC, SUMMRY, and SUMMR2. These are not
discussed specifically in this report. For information on the
original DARTAB, consult the document describing the code (Be81).
DARTAB has been modified for PRESTO-EPA-POP so that the program is
treated as a subroutine.
DARTAB uses dosimetric and health effects data from the
methodologies of RADRISK (Du80). RADRISK uses a life-table model
to calculate the human health risk to a cohort of 100,000 people
from a constant input of 1 pCi/yr (0.037 Bq/yr) via ingestion and
inhalation over a lifetime (70.7 yr).
These intake conditions are approximated in PRESTO-EPA-POP by
calculating an average intake over the span of the assessment of
each type of intake. RADRISK data files are accessed directly by
DARTAB.
2-68
-------
The PC version of the PRESTO-EPA-POP model simplifies the
submodel by accessing the datal and genetic health effects
conversion factors from a precalculated fatal and genetic health
effects conversion factor table instead of reading them out from
the complex RADRISK file. The modified submodel is designated as
HESTAB.
DPLT - The subroutine DPLT is called by AIRTRM and computes a
correction factor for plume depletion. To make this calculation,
DPLT calls subroutines SIGMAZ and SIMPUN.
ERORF - This subroutine uses the universal soil loss
equation, USLE, developed by the U.S. Department of Agriculture
(USDA61) to determine sediment loading for rain-driven surface
erosion. Estimation methods and tabulations for factors used in
USLE have been organized and published by McEloy et. al. (McE76).
The code user inputs all six of these factor values. The
calculated erosion rate is returned to MAIN where it is converted
to an annual erosion rate in meters. This erosion rate is
utilized by MAIN to determine the thickness of the cap.
FCN - This function subprogram returns to QUANC8 a functional
evaluation of the integral used in calculation of the aquifer
decay-dispersion correction factor. The routine is written in
double precision to facilitate interaction with the double
precision routine QUANC8.
FOOD. FOODA - Subroutine FOOD is called only once per
simulation and calculates the average concentration of each
radionuclide in foods contaminated by atmospheric deposition and
root uptake. The deposition input to FOOD is calculated in
subroutine AIRTRM. The equations and internal parameters used by
FOOD are those in AIRDOS-EPA (Moo79). Output from FOOD is used by
the subroutine HUMEX to calculate the human exposure via ingestion
of these contaminated foodstuffs. Subroutine FOODA is called from
MAIN each simulation year.
HUMEX. HUMEXA - Subroutine HUMEX accepts user input and
receives averaged data from subroutines AIRTRM, FOOD, IRRIG, and
VERHOR to calculate the average annual human exposures via
ingestion and inhalation. Output from HUMEX supplies the input to
the DARTAB subroutines for calculations of risk and dose and
tabulation of health results. Subroutine HUMEXA is called from
2-69
-------
MAIN each simulation year.
INFIL - The subroutine INFIL is based on a model by Hung
(Hu83b) and calculates annual infiltration through the trench cap.
INFIL calls subroutine SOIL and ROUT. Inputs to INFIL include
hourly precipitation, daily temperature, and various trench cap
characteristics.
IRRIG. IRRIGA - Foods may be irrigated with contaminated
water from either surface or groundwater sources. Input to IRRIG,
which is called only once per simulation, includes the time-
averaged radionuclide concentrations in well or surface water
calculated by VERHOR or subroutine SURSOL, respectively. IRRIG
calls the function COV and uses the equations in AIRDOS-EPA
(Moo79, FiSOb) to calculate the time-averaged concentration of
each radionuclide from direct deposition by irrigation and
subsequent root uptake in food crops. Subroutine IRRIGA is called
from MAIN each simulation year.
LEACH - Subroutine LEACH calculates the amount of each
radionuclide that leaves the trench each year from the trench
contents. Losses may be via transport through the trench bottom
or overflow from the trench. There are three independent user-
specified methods that may be used to calculate these amounts.
The option is chosen by specifying a value from one through three
for parameter LEAOPT. Table 2-1 lists the calculational methods
corresponding to values of LEAOPT. The distribution coefficient
option 1, utilizes a Kd approach to calculate the radionuclide
concentrations released from the wastes to the water, while option
2 uses a solubility estimate to limit the radionuclide
concentrations released from the trench estimated from option 1.
If the user selects LEAOPT = 3, then a user-specified fraction of
the total radionuclide concentration in the waste is lost through
the trench bottom annually. Output from LEACH is the activity
leaving the trench annually for each radionuclide through the
bottom of the trench and by overflowing.
OUT - This subroutine produces annual summaries for the
trench cap status, trench water balance, amount of water leaving
the trench, and the radionuclide contents in the trench water,
trench overflow water, aquifer, well water, and on the ground
surface. The user may choose to print these summaries for every
year or less frequently by specifying the appropriate values of
2-70
-------
IPRTI, IPRT2, and IDELT in the input data file.
OUANC8 - This subprogram employs a Newton-Cotes 8-panel
quadrature formula (For77). The integral to be evaluated is
specified by the function FCN.
ROUT - This subprogram obtains the hourly excess rainfall by
calling the SOIL subprogram and subsequently routing the overland
flow by using the basic differential equations listed in Section
2.2.1 to obtain the hourly rate of overland flow and the depth of
overland flow storage. The time step used in this subprogram is
fixed at one hour without any problem on the stability of
numerical analysis. Therefore, the computer process time on this
flood routing is comfortably short. This subroutine is called by
INFIL.
SIGMAZ - This subroutine is called by both AIRTRM and DPLT to
compute the vertical atmospheric dispersion parameters. Depending
on the choice of parameter specified in the input data set, SIGMAZ
will calculate the dispersion parameters by one of eight schemes.
Necessary input data include the downwind distance, stability
class, Hosker roughness parameter, and lid height. Other data
necessary for Lagrangian interpolations (by function YLAG) are
built-in internally in SIZMAZ.
SIMPUN - This subroutine, originally written by Barish
(Bar70), uses Simpson's rule to integrate along the ground-level
centerline of the atmospheric plume to compute the depletion
fraction. All input to SIMPUN is supplied by DPLT, the subroutine
that calls SIMPUN and to which the results are returned.
SOIL - This subprogram calculates the hourly excess rainfall,
the amount of pellicular water storage, the hourly rate of gravity
water flow, and the hourly rate of infiltration based on the basic
equations listed in Section 2.2.1. This subroutine is called by
the subprogram ROUT.
SOURCE - Subroutine SOURCE reads the input required to
initialize and quantify transport parameters, except those
required for subroutine INFIL. Data concerning program control,
climatic description, trench description, aquifer description,
atmospheric description, site-surface description, and
2-71
-------
radionuclide description are read in by SOURCE. SOURCE also
prints out these data before any calculated results are printed
out.
SURSOL - Subroutine SURSOL computes the amount of soluble
radionuclide that enters the stream annually. Input variables to
SURSOL include the average depth of active exchange in the soil,
the average down-slope distance to the stream, the cross-slope
extent of the spillage, the average annual infiltration, the bulk
density of soil, the amount of spillage, and the surface soil
distribution coefficients. Variables printed out from SURSOL
include the amounts of radionuclide going to the stream and the
deep soil layers and the radionuclide concentration in the
interstitial water of the contaminated surface region.
SUSPND - This subroutine calculates the above trench
atmospheric source term coming from the ground surface by two
pathways, a wind-driven resuspension and a resuspension due to
mechanical disturbance. Input variables include the current year
of simulation, the spatial area of the contaminated surface, the
radionuclide concentration on the ground surface, the beginning
and ending years of mechanical disturbances, the resuspension
rate, and the wind velocity. SUSPND assumes that all
radionuclides to be resuspended are deposited on the soil surface
at a simulation time zero. The resuspension factor calculated
uses the empirical equation of Anspaugh, et al. (An75).
The atmospheric source term is returned to MAIN and is used
along with X/Q to calculate the air concentration of each
radionuclide available for deposition onto foodstuffs and for
inhalation by the general population. The value of X/Q is
calculated by AIRTRM.
TRENCH - This subroutine determines the trench water balance.
Input variables include trench dimensions, porosity and
permeability of trench contents, trench water volume from the
previous year, length of the saturated zone, and annual
precipitation and infiltration. Output from TRENCH includes the
maximum depth of water in the trench, the volume of water in the
trench, volume of water overflowing the trench, and water volume
lost from the bottom of the trench.
The amount of water which overflows the trench is calculated
2-72
-------
by comparing the maximum water depth to the trench depth and
overflowing any amount greater than the trench volume. The
variables VOLO, VOLB, OLDWAT, and DMAX that quantify overflow,
bottom loss, water level during previous year, and maximum water
depth in trench, respectively, are used by the subroutine LEACH,
discussed previously.
VERHOR - This subroutine calculates the amount of each
radionuclide that reaches the irrigation/drinking water well in a
given year. Variables evaluated elsewhere in the code and input
to VERHOR include the current year of the simulation, transit time
from the trench to the well, the volume of water leaving the
trench bottom, the amount of each radionuclide leaving the bottom
of the trench, the amount of radionuclide reaching the aquifer
from the contaminated surface region, and the radioactive decay
constant.
YLAG - This function performs a Lagrangian interpolation as
part of the atmospheric transport calculations. The original
program was written by Brooks and Long (Br70) and adapted for use
here. All input data are supplied by subroutine SIGMAZ.
XPRESS - This subroutine computes and stores exponential
decay factors to be used repetitively in the nuclide loops.
XPRESS saves a substantial amount of computing time.
2.4.3 PC Version of PRESTO-EPA-POP Model
The mainframe version of the model employed the DARTAB
subroutine, which prohibited executing the model in a personal
computer because it was designed to read-in the necessary input
data from the RADRISK file. Therefore, to execute the model in a
personal computer, it is necessary to modify the model design to
reduce the core memory requirement and to improve the process
efficiency.
The major modifications of the model include the replacement
of the DARTAB subroutine with the HESTAB subroutine, addition of
HUNG function, elimination of the QUANC8 function, and adjustment
of I/O statements [Ro87].
2-73
-------
The replacement of the DARTAB subroutine with HESTAB has
reduced considerably the core memory requirement. To calculate
the fatal cancer deaths and serious genetic effects resulting from
human exposures, the HESTAB subroutine reads a set of fatal and
genetic health effect conversion factors from the health effects
conversion factor input file, which were precalculated from the
RADRISK file using the same methodology as used in the original
DARTAB subroutine. The results of the calculation are printed out
in much the same format used in the mainframe version of the
model.
The elimination of the QUANC8 function, a function for
integrating an algebraic function having an infinite limit,
prevents the tedious numerical integration of Hung's correction
factor [Hu80]. The modified model employs an analytical solution
derived by Hung [Hu86] which is calculated in HUNG function. This
modification results in some savings in the process time. In
addition, the model calculates and prints out the dose equivalent
incurred through the drinking water pathway as a component of the
ingestion pathway.
This modified PC version of PRESTO-EPA-POP is simply called
PRESTO-EPA-POP throughout the rest of this documentation.
2.5 Input File Requirements
There are three input files required for the execution of
PRESTO-EPA-POP. They are: (1) the environmental and nuclide-
specific input file; (2) the INFIL subroutine input file, and (3)
the dosimetric input file. Details of the input files are
presented in the following sections. The requirements described
in this section apply to the PC version of the model.
2.5.1 Environmental and Nuclide-Specific Input File
This input file is used to supply the physical and
hydrogeological characteristics of the disposal site, the
meteorological data for atmospheric dispersion and deposition, the
data for the biological pathways, and the radionuclide
characteristics and inventories.
2-74
-------
The data set also contains parameters describing the site
characteristics, the disposal technology, the human exposure
characteristics, and some specific parameters characterizing the
site and exposure scenarios. For simplification, this input file
is referred to as the main input file throughout this
documentation.
2.5.2 INFIL Subroutine Input File
The INFIL subroutine input file is used to calculate
rainwater infiltrating through the trench cap into the waste
trench. It is divided into two categories, trench cap
characteristics and local hydrological and meteorological data.
2.5.3 Health Effects Input File
This file contains the fatal and genetic health effects
conversion factors for each radionuclide. It is used to calculate
the cumulative fatal health effects and genetic health effects
over the entire period of risk assessment.
These conversion factors are independent of disposal site and
disposal method; therefore, this file is incorporated into the
program and requires no changes from the user under normal
application.
The format for the environmental and nuclide-specific, INFIL
subroutine, and dosimetric input files are listed in Appendix D,
Tables D-l, D-2, and D-3, respectively.
2.6 OUTPUT FILE DESCRIPTION
The output of PRESTO-EPA-POP is designed to be self-
explanatory and contains descriptive comments, definitions, and
intermediate and final tabulations. It is assumed that the output
may be analyzed by users unfamiliar with the PRESTO-EPA-POP
structure. The PRESTO-EPA-POP output is organized into nine
sections, each described below.
2-75
-------
2.6.1 Replication of Input Data
The first section of the PRESTO-EPA-POP output is replication
of the user supplied input data files as read in. This provides
the user with a record of the input data set used for later result
identification and analysis. PRESTO-EPA-POP also organizes this
input data to allow for easy interpretation. A summary of the
input data files (1) and (2) is also printed according to data
type and transport system. These descriptive summaries are output
in sentence format to improve ease of review.
2.6.2 Radionuclide Summary Tables
A set of tables under the heading "Nuclide Information" next
summarizes the radionuclide data used for the transport
calculations. These tables include radionuclide distribution
coefficients, nuclide inventories, and waste stream inventories.
2.6.3 INFIL Input/Output
The third output section of PRESTO-EPA-POP consists of the
input data and results for the subroutine INFIL. The input to
subroutine INFIL is presented first and consists of infiltration
control, monthly averages for hours of sunshine, daily average
temperatures, hourly rainfall amounts, and specific trench
characteristics (snow melt coefficients, trench cover thickness
and width, cover slope, porosity, and permeability).
With these input data, subroutine INFIL calculates and
outputs several data items. The most important of these are the
annual infiltration and annual precipitation. Annual evaporation,
runoff and cap infiltration are also calculated and output.
2.6.4 Annual Summaries
Input control parameters determine the years for which
intermediate results are printed. For these years, a number of
hydrological and transport variables are output. Included are
trench cap status, water depth in the trench, water loss by
overflow and drainage from the trench, and trench radionuclide
2-76
-------
inventories. Radionuclide concentrations and flux values are
also given for key pathways and regions of interest.
2.6.5 Radionuclide Uptake and Concentrations
The radionuclide concentration tables present, by
radionuclide, the average concentration over the entire assessment
period and the maximum concentration in the atmosphere, on the
ground surface, and in the well and stream water.
The total uptake factors quantify, on a radionuclide-specific
basis, the annual amount of nuclide uptake by the critical
population group from all potential sources. For inhalation, it
is just the quantity of nuclides inhaled. For ingestion, it is
the total consumption of nuclides (pCi/yr) from contaminated
vegetation, meat, milk, and drinking water.
2.6.6 HESTAB Result Tables
These tables present a summary of cumulative fatal and
genetic health effects by exposure pathways and by radionuclide
2.6.7 Cumulative Summary Tables
These tables present a summary of the cumulative fatal health
effects and genetic health effects, the collective radionuclide
being pump out of the well, and the cumulative release of
radionuclide to the downstream basin for each radionuclide.
Finally, the total number of fatal health effects and genetic
health effects resulting from the disposal of the waste are listed
as the conclusion of the analysis.
2-77
-------
3. DESCRIPTION OF SYSPOP OPERATION SYSTEM
The user-friendly PRESTO-EPA-POP Operation System Program,
SYSPOP, is the combination of the input file preparation program
and the PC version of PRESTO-EPA-POP model which simplifies the
operation of PRESTO-EPA-POP. This chapter describes the
structure of the operation system.
3.1 PRESTO-EPA-POP INPUT REQUIREMENTS
There are three input files required for the execution of
PRESTO-EPA-POP. They are: (1) the environmental and nuclide-
specific input file, (2) the INFIL subroutine input file, and (3)
the health effects input file. Details of the input files are
discussed previously in Sections 2.5.1 through 2.5.3.
The input data formats for the environmental and nuclide-
specific, INFIL subroutine, and health effects input files are
listed in Appendix D, Tables D-l, D-2, and D-3, respectively.
3.2 DESCRIPTION OF THE SYSPOP OPERATION SYSTEM
3.2.1 General
The PRESTO-EPA-POP operation system, SYSPOP, is designed to
help the user of the PRESTO-EPA-POP model to prepare the input
data files, to perform necessary file management for the
execution of the compiled PRESTO-EPA-POP objective module, and to
automate the execution of the PRESTO-EPA-POP model. In creating
an input data file, the program also directs users to enter each
individual datum in the proper format and data field.
The program provides the capability of editing the input
data file which includes line editing of the input file, display
of the input file, line-by-line comparison with a predesignated
input file, and the insertion and deletion of radionuclides to be
considered in the analysis.
In managing the data files for the execution of the compiled
3-1
-------
objective module, the operation system helps users to clear the
files which need to be deleted, check the availability of the
storage volume, and save the preexisting output file.
Although there are three input files required to execute the
PRESTO-EPA-POP model, the SYSPOP operation system includes the
preparation of the environmental and nuclide-specific input file.
This is because this file is the most complicated input file of
all and needs the most attention.
Three INFIL subroutine input files are included in the
operation system. They represent the input files for application
to the humid permeable zone (INFILSE.DAT), humid impermeable zone
(INFILNE.DAT), and arid permeable zone (INFILSW.DAT),
respectively. The user may select the one most suitable to the
site being analyzed as the input file (INFIL.DAT). This can be
done by renaming the selected INFIL file (e.g. INFILSE.DAT) as
INFIL.DAT which will then be used as the input file for the
system operation. The preparation of the INFIL subroutine input
file is excluded from the operation system because there would be
only one line of input data to change if there is a change in the
trench cap design.
The preparation of the health effects input file is also
excluded from the SYSPOP program because the file is independent
of site location and facility design. No change is necessary
under a normal application.
3.2.2 System Structure
The structure of the PRESTO-EPA-POP operation system
consists of many subprograms each of which performs a designated
function. The subprograms include 10 operation programs, 7 batch
programs, 3 direct input data files, 3 system data files, 2
permanent data files, and 2 compiled objective programs.
The operation programs are DATACHK.EXE, INPOPC.EXE,
INPOPD.EXE, INPOPE.EXE, INPOPI.EXE, INPOPR.EXE, LOGO.EXE,
MENU.EXE, MENUED.EXE, and RUNPOP.EXE. The batch programs are
COPFIL.BAT, COPY1.BAT, COPY2.BAT, COPY3.BAT, COPY4.BAT,
RUNPOP.BAT, and SYSPOP.BAT. The three direct input files are
INPOP.DAT, INFIL.DAT, and POPFAC.DAT, and the two permanent
3-2
-------
system data files include PRPOPFAC.DAT and PRSTPOP.DAT.
the compiled FORTRAN objective files are POPPC.EXE and
DATACHK.EXE.
Finally,
The functions of each subprogram are described as follows:
DATACHK.EXE:
INPOPC.EXE
INPOPD.EXE:
INPOPE.EXE:
an executable file used to locate illegal
input data in the environmental and
radionuclide-specific input file;
an operation program which allows the user to
make a line-by-line comparison of the input
file with a predesignated standard input file
to locate errors in the input file;
an operation program which allows the user to
delete radionuclides of no concern, thus
saving the calculation time;
an operation program which allows the user to
make line editing of the input file;
INPOPI.EXE:
INPOPR.EXE:
LOGO.EXE:
MENU.EXE:
MENUED.EXE:
POPPC.EXE:
an operation program which allows the user to
insert radionuclides of his interest;
an operation program which allows the user to
have quick review of the entire input file;
a program which displays the logo of the
SYSPOP program;
an operation program which displays the main
menu of operation and subsequently loads the
operation program selected by the operator;
an operation program which displays the
editing menu and subsequently loads the
editing program selected by the operator;
an executable PRESTO-EPA-POP module used
primarily for the calculation of the fatal
and genetic health effects;
3-3
-------
RUNPOP.EXE:
COPFIL.BAT:
COPY1.BAT:
COPY2.BAT:
COPY3.BAT:
COPY4.BAT:
RUNPOPB.BAT:
SYSPOP.BAT:
an operation program which performs file
management, including the saving of the
preexisting output file, checking of the
available storage volume, and execution of
the PRESTO-EPA-POP program;
a batch program which copies an input data
file from the standard input data file;
a batch program which duplicates the current
input file, standard file and dosimetric file
for editing use;
a batch program which replaces the current
file with the updated file for editing use;
a batch program which replaces the old files
with updated final files and deletes all the
temporary files during the course of editing;
a batch program which deletes all of the
temporary files without replacing old files;
a batch program which prepares the files and
issues the command to execute the PRESTO-EPA-
POP model;
a batch program which issues the command to
run the LOGO.EXE program;
INFIL.DAT:
INPOP.DAT:
POPFAC.DAT:
PRPOPFAC.DAT:
an input file containing trench cap
characteristic and local meteorological data;
an input file containing environmental and
radionuclide-specific data;
an input data file which contains the fatal
health effects and genetic health effects
conversion factors;
a permanent data file containing the fatal
health effects and genetic health effects
3-4
-------
conversion factors, which includes all 40
radionuclides built in the model;
PRSTPOP.DAT:
STPOP.DAT:
a permanent data file containing the
standardized input files equivalent to
INPOP.DAT and includes all 40 radionuclides
built in the model; and
a standardized input file equivalent to the
INPOP.DAT file.
3-5
-------
4. SYSTEM INSTALLATION
The PRESTO-EPA-POP operation system is designed to be
operated on an IBM PC/AT compatible microcomputer. The computer
should be equipped with a math co-processor (80287 or equivalent)
and a color monitor having video graphic array (VGR)) and should
have a minimum of one megabyte of disk storage after all of the
software has been stored in the disk.
The system software is recommended to be installed on a hard
disk drive and the same drive can be used to store the output
file and the temporary output file. The operation system
software includes the executable module of PRESTO-EPA-POP, the
sample input and output, and the standard input files. To
install the system, simply copy all of the files into the same
directory. The system will then be ready for operation.
4-1
-------
5.
SYSTEM OPERATIONS
The PRESTO-EPA-POP operation system program is a menu-
directed, user-friendly system. Detailed instructions of the
system operations are displayed on the screen so that the users
may proceed with the operations by simply following the
instructions printed on the screen. This chapter provides the
supplemental instructions for system operation.
5.1 START UP
To start the system proceed as follows:
1. Turn on the computer, access disk operation system
(DOS), and change the directory for which the software
package is stored;
2. Type the command, "SYSPOP"; the logo of the operation
system will appear;
3. Press any key to display the main menu; see Figure 5-1,
PRESTO-EPA-POP OPERATION SYSTEM Version 2.1
MAIN MENU
1. Copy a New Input File from
the Standard Input File
2. Edit the Existing Input File
3. Test the Current Input File
4. Execute PRESTO-EPA-POP
5. Print out POP.OUT
6. End of Operation
5-1
-------
*** Enter your selection number
Figure 5-1. Main menu of the operation system.
The system is now ready to receive the user's selection for
operation. Upon receiving the selected number, the system will
transfer the operation to the corresponding subsystem. When "End
of Operation" is selected, the system will return to the DOS
system.
5.2 COPY A NEW INPUT FILE FROM THE STANDARD INPUT FILE
This option is recommended for creating a new input file.
Since the main input file, INPOP.DAT, contains many data which
can be used as default and do not require change from the
standardized file, it is more efficient to create a new main file
by copying the standardized file to prevent massive typing. Any
changes of the site-specific data can then be edited from the
copied file using the file editing operation discussed in the
following sections.
To exercise this option, simply respond "1" to the request
(see Figure 5-1). To avoid this selection being made by accident
and subsequent loss of the existing input file, the system
responds with a warning to make sure this is indeed your
selection. This warning tells you that the copying of a new
input file will result in the loss of the old input file. Upon
your confirmation, the system will duplicate the permanent
standard file built into the system and then return to the main
menu after informing you of the completion of the copy operation.
The copied new file is designated as "INPOP.DAT."
5.3 EDIT THE EXISTING INPUT FILE
This option is designed to allow the user to edit the input
file which is stored in the INPOP.DAT file. This selection
provides five functions: 1) edit the POP input file; 2} review
5-2
-------
the POP input file; 3) review the input file; 4) delete
radionuclides; and 5) insert radionuclides.
When the selection is made by the user, the system displays
the menu for input file editing as shown in Figure 5-2.
5.3.1 Edit the POP Input File
When the option of editing the POP input file is selected
the system will transfer the control to the INPOPE.EXE program
which is followed by the read-in of the current input file.
If the input file is incomplete, the program will give an
error message, "Input file is incomplete" and then return to the
main menu. This case will never happen in normal operation.
PRESTO-EPA-POP OPERATION SYSTEM, Version 2.1
MENU FOR EDITING
1. Edit the POP Input File
2. Compare the POP Input File with
the Standard File
3. Review the POP Input file
4. Delete radionuclides
5. Insert radionuclides
6. End of Editing
Figure 5-2. Sub-Menu for Input File Editing
If the input file is complete, the system will display the
instructions for file editing, as shown in Figure 5-3.
5-3
-------
INSTRUCTIONS
1. Input the starting card number (and nuclide number if the
starting card number is above 28) of the block of lines you
wish to edit;
2. Highlight the succeeding lines by Pressing 'enter1, '!' or
'I1 until the line you wish to edit is highlighted;
3. Edit the line by using '-' to copy, new character to replace
the old one, 'backspace' or ' 'to change the previous entry,
"ins1 to insert, and 'del' to delete.
4. Press 'enter1 when all of the necessary editing is completed;
5. Repeat steps 3 and 4 until all of the line you wish to edit
are completed;
6. To quit or move to another page, press 'esc' at any time
Figure 5-3. Instructions for File Editing.
The system will continue to request the first card number of the
block (altogether 21 lines or cards in a block) that you wish to
edit. If the card number is No. 29, the program will make an
additional request for the first radionuclide number of the block
that you wish to edit. When the system receives your response,
you should see the screen display a whole block of 21-line input
data with its top line being highlighted indicating that the line
is being edited.
To edit the highlighted line, proceed as instructed in
Figure 5-3. After the updated line data are entered, the system
will display the updated line of input data and move on to
highlight the next line for editing.
To terminate the editing of the current block of input data,
you may simply press the 'esc' key. The system will go back to
5-4
-------
request the first card number of the block that you wish to edit.
This will commence another editing cycle for the newly requested
block.
You may escape from the editing mode by pressing the 'esc'
key when the first card number of the editing block is requested.
Based on your response directed by the menu, the system will
either replace the input file with an updated file or do nothing
to the existing input file and return to the menu for editing.
5.3.2 Compare the Input File with the Standard File
This option provides the capability of a line-by-line
comparison of the current input file, INPOP.DAT, with the
standard file, STPOP.DAT, and is primarily designed for checking
the format and numerical field of the input data in the current
file. It is particularly useful in locating invalid input data
which causes a run time error in the execution of the PRESTO-EPA-
POP model.
5.3.3 Review the POP Input File
This option provides the capability for quick review of the
entire current input file. It can be used to check the
completeness of the file or to scan the input file for any
obvious error.
When this option is selected, the system will start with a
read-in of the current input file and check the completeness of
the file. If the file is incomplete, the system will issue a
warning message "INPOP.DAT is incomplete" and then return to the
menu for editing. If the file is complete, the system will
display the input data starting from card no. 1 and display 20
lines on a single page. To view the next page, you may simply
press the 'enter1 key. You may terminate the reviewing option at
any time by pressing the 'esc1 key. When this is done, the
system will return to the menu for editing and will be ready for
another selection.
5.3.4 Delete Radionuclides
5-5
-------
This option provides the capability of deleting
radionuclides of no interest to the user from the input files.
For maintaining the capability of comparing with the standard
input file and matching the number of radionuclides with the
health effects conversion factor table, the same deletion of a
radionuclide is automatically conducted for the standard input
file and health effects conversion factor file.
When this option is selected, the system will issue the
warning, "Deletion of radionuclides from the input file will also
result in the deletion of the same radionuclides from the
standard input file and dose conversion factor table" to give the
user a chance to save the existing files.
Upon the approval of the user, the system will proceed with
matching the radionuclide name in the current input file,
standard file, and dose conversion factor file. If there are
inconsistencies, the system will print out the inconsistencies
and return to the menu for editing. If no inconsistency is
found, the system will proceed to print out the current
radionuclide sequence and request the range of radionuclide
numbers to be deleted.
Notice that the model takes up to 40 radionuclides with each
radionuclide assigned a sequence number from 1 to 40. In
accepting the user-specified nuclides for deletion, the system
takes the sequence numbers as a base to identify radionuclides
rather than using radionuclide names. Therefore, the range of
"radionuclide sequence numbers" must fall between 1 and 40 or the
program will not accept the entry.
Upon receiving the range of radionuclide numbers to be
deleted, the system will proceed with the deletion of the
designated radionuclides from the current input file, the
standard input file, and the health effects conversion file;
print out the new radionuclide sequence; and ask for another
block of deletion. If the user approves the request, the system
will continue to request the range of radionuclide sequence
numbers to be deleted, and the whole cycle will be repeated. If
the user denies the request, the system will move on to ask if
the user wants to save the new files. If it is approved, the
system will replace all three files with the updated files and
return to the menu for another editing operation; otherwise, the
5-6
-------
system will return to the menu for editing without replacing the
updated files.
5.3.5 Insert Radionuclides
This option provides the capability of inserting those
radionuclides into the input files which are of particular
interest to the user. For maintaining the capability of
comparing with the standard input file and matching the number of
radionuclides with the health effects conversion file, the same
insertion of radionuclides is also automatically conducted for
the standard input file and health effects conversion file.
When this option is selected, the system will issue the
warning "Insertion of radionuclides into the input file will also
result in the insertion of the same radionuclides into the
standard input file and health effects conversion factor table."
This warning gives the user a chance to save the existing files.
Upon approval from the user, the system will proceed with
matching the radionuclide name between the current input file,
standard file, and health effects conversion factor file. If
there are inconsistencies, the system will print out the
inconsistencies and return to the menu for editing. If no
inconsistency is found, the system will proceed to print out the
current radionuclide sequence and request for the range of
radionuclide sequence numbers to be inserted.
As explained earlier, the maximum number of radionuclide
that the model can handle is 40. Therefore, any attempt to
insert a number of radionuclides, which causes the total number
of radionuclide to exceed 40, will be rejected by the system.
Upon receiving the range of radionuclide sequence numbers to
be inserted, the system will proceed to insert the designated
radionuclides into the current input file, the standard input
file, and the health effects conversion file. The system will
continue to print out the new radionuclide sequence and ask for
another insertion until the user denies the request. Then the
system will move on to ask if the user wants to save the new
files. If it is approved, the system will replace all three
5-7
-------
files with the updated files and return to the menu for editing.
Otherwise, the system will return to the menu for editing without
replacing the updated files.
5.3.6 End of Editing
When this selection is entered, the program will leave the
editing mode and return to the main menu for another selection.
5.4 TEST THE CURRENT INPUT FILE
This option allows the user to test the entire input file
for illegal real numbers and integers. Since the PRESTO-EPA-POP
code will not take any illegal real numbers and integers, it is
important to test the file before you run the code.
To test for the illegal real numbers and integers, simply
respond "3" to the request, Figure 5-1. The system responds
with an instruction and then tests the input data line-by-line
and page-by-page. Following a successful test of a data line,
the system it will display the line tested. When the test
reaches the end of the page without encountering any illegal
numbers, a message, "No illegal numbers found," and a request for
the approval of continuation will be displayed. Upon the user's
approval of continuation, the system will continue by testing the
following page. The system will go back to the main menu
automatically when the testing of the entire file is completed.
When an illegal number is found, the testing will be
terminated and followed by an error message. The search for the
illegal number in the data line shall be proceeded manually by
the operator.
5.5 EXECUTE PRESTO-EPA-POP
The option for the execution of PRESTO-EPA-POP is designed
to prepare and run PRESTO-EPA-POP. The preparation includes the
saving of the existing output file, the reminder of checking the
availability of disk storage, and the status of the INFIL
subroutine input file, INFIL.DAT.
5-8
-------
When the option is selected, the system will ask if the user
wants to save the existing output file, POP.OUT. If the user's
response is "no," the system will move directly to check the
available disk storage space. If the user's response is "yes,"
the system will ask for a new name of the file. Upon receiving
the new name of the output file, the system will rename the
POP.OUT file as designated and move on to check the available
disk storage space.
The system will not check the available disk storage
automatically. Instead, it will print out the existing available
disk storage and let the user compare it with the minimum storage
requirement of 1 megabyte. This is done by asking the user "Do
you have enough free space?" If the answer is "no," the system
will remind the user to secure more free space and return to the
main menu. If the user's response is "yes," then the system will
ask if the existing INFIL subroutine input file, INFIL.DAT, is
current. If the user's response to this question is "no," the
system will remind the user to update the INFIL.DAT and return to
the main menu. If the user's response is "yes," the system will
issue the message that the system is ready to run the PRESTO-EPA-
POP model and remind the user that the output file will be saved
in the POP.OUT file.
Upon final user approval, the system will automatically copy
INFIL.DAT, INPOP.DAT, and POPFAC.DAT and then run the PRESTO-EPA-
POP program.
The PRESTO-EPA-POP is an extensive FORTRAN program requiring
considerable time to execute the entire program. On a 286 IBM
compatible computer, it takes approximately 250 minutes to
complete a run involving 40 radionuclides; whereas; when it is
reduced to 5 radionuclides, it takes only 35 minutes to run. To
inform the user of the status of the run during execution, the
system will print out the year of health effects that the model
is calculating. The print out will continue each year up to 1000
years and then every 100 years up to 10,000 years on a standard
run.
When the execution is completed, the system will issue the
message "Execution of PRESTO-EPA-POP completed, and your output
is stored in POP.OUT." The system will return to the main menu
after receiving approval to continue.
5-9
-------
5.6 PRINT OUT POP.OUT
This option allows the user to print out the results of the
PRESTO-EPA-POP run which is stored in the file, POP.OUT. Due to
the fact that the capabilities of a word processor today are
remarkable, one may prefer to print out the output file through a
word processor. A word processor can print out a text file in
various options to satisfy user's needs. For instance, a land-
scape printing with a reduced character size (16.67 cpi) can
considerably reduce the number of pages to be printed.
When this option is selected, the system will simply display
a recommendation to employ the user's favorite word processor for
printing the outputs and then return to the main menu.
5.7 END OF OPERATION
When this option is selected, the system will leave the
SYSPOP operation system and return to the DOS system.
5-10
-------
REFERENCES
An75 Anspaugh, L. R., J. J. Shinn, P. L. Phelps, and N. C.
Kennedy, "Resuspension and Redistribution of Plutonium
in Soils," Health Phys. 29:571-582, 1975.
BaeSl Baes, C. F.( 111, and R. D. Sharp, "A Method for
Determination of Leaching Rates of Elements in
Agricultural Soils," submitted to J. Env. Quality,
1981.
Bae82 Baes, C. F.; III, R. D. Sharp, A. L. Sjoreen and
R. W. Shor, A Review and Analysis of Parameters for
Assessing Transport of Environmentally Released
Radionuclides Through Agriculture, ORNL-5786 (Oak Ridge
National Laboratory), 1982.
Bar70 Barish, J., The Computing Technology Center Numerical
Analysis Library (G. W. Westley and J.A. Watts,
eds.), pp. 76-80, Union Carbide Corporation Nuclear
Division, Computing Technology Center, Oak Ridge,
Tennessee, Report CTC-39, 1970.
Be81 Begovich, C. L., K. F. Eckerman, E. C. Schlatter, and
S. Y. Ohr, DARTAB: A Program to Combine Airborne
Radionuclide Environmental Exposure Data with
Dosimetric and Health Effects Data to Generate
Tabulations of Predicted Impacts, ORNL-5692 (Oak Ridge
National Laboratory, Oak Ridge, Tennessee), 1981.
BSI66 British Standards Institute, Recommendation for Data on
Shielding from Ionizing Radiation, Part I, Shielding
from Gamma Radiation, London, British Standard 4094,
Part I, 1966.
Br70 Brooks, A. A., and E. C. Long, The Computing
Technology Center Numerical Analysis Library (G. W.
Westley and J. A. Watts, eds.), pp. 2-6, Union Carbide
Corporation Nuclear Division, Computing Technology
Center, Oak Ridge, Tennessee, Report CTC-39, 1970.
Cla78 Clap, R. B. and G. M. Hornberger, Water Resources
R-l
-------
Research Journal, p. 14,601, 1978.
Cle68 Clebsch, A., Jr., "Beatty Facility - Near Beatty,
Nevada: Geology and Hydrology of a Proposed Site for
Burial of Solid Radioactive Waste Southeast of Beatty,
Nye County, Nevada," in Land Burial of Solid
Radioactive Waste: Study of Commercial Operations and
Facilities, pp. 70-103, WASH-1143, 1968.
Cu76 Culkowski, W. M. and M. R. Patterson, A Comprehensive
Atmospheric Transport and Diffusion Model, Oak Ridge
National Laboratory, Oak Ridge, Tennessee, Report
ORNL/NSF/EATC-17, 1976.
Du80 Dunning, D. E., Jr., R. W. Leggett, and M. G.
Yalcintas, A Combined Methodology for Estimating Dose
Rates and Health Effects from Exposures to Radioactive
Pollutants, ORNL/TM-7105 (Oak Ridge National
Laboratory, Oak Ridge, Tennessee), 1980.
Ec81 Eckerman, K. F., M. R. Ford, and S. B. Watson, Internal
Dosimetry Data and Methods of ICRP - Part 2, Vol. 1:
Committed Dose Equivalent and Secondary Limits,
NUREG/CR-1962 Vol. 1, ORNL/NUREG/ TM-433/VI (Oak Ridge
National Laboratory, Oak Ridge, Tennessee), 1981.
Ei75 Eisenhauer, C. M. and G. L. Simmons, "Point
Isotopic Gamma-Ray Buildup Factor in Concrete," Nuclear
Sci. Eng. 56:263-270, 1975.
EEI84 Envirodyne Engineers, Inc., Characterization of Health
Risks and Disposal Costs Associated with Alternative
Methods for Land Disposal of Low-Level Radioactive
Waste, 1984.
EPA83 U.S. Environmental Protection Agency, PRESTO-EPA: A
Low-Level Radioactive Waste Environmental Transport and
Risk Assessment Code Methodology and User's Manual,
Prepared under Contract No. W-7405-eng-26, Interagency
Agreement No. EPA-D--89-F-000-60, U.S. Environmental
Protection Agency, Washington, D.C., April 1983.
EPA85 U.S. Environmental Protection Agency, High-Level and
R-2
-------
Transuranic Radioactive Wastes - Background Information
Document for Final Rule, EPA 520/1-85-023, Washington,
D.C., 1985.
EPA87a U.S. Environmental Protection Agency, PRESTO-EPA-POP: A
Low-Level Radioactive Waste Environmental Transport and
Risk Assessment Code - Vol. 1, Methodology Manual, EPA
520/1-87-024-1, Washington, B.C., 1987.
EPA87b U.S. Environmental Protection Agency, PRESTO-EPA-POP:
A Low-Level Radioactive Waste Environmental Transport
and Risk Assessment Code - Vol. 2, User's Manual, EPA
520/1-87-024-2, Washington, B.C., 1987.
EPA87c U.S. Environmental Protection Agency, PRESTO-EPA-BEEP:
A Low-Level Radioactive Waste Environmental Transport
and Risk Assessment Code, Bocumentation and User's
Manual, EPA 520/1-87-025, Washington, B.C., 1987.
EPA87d U.S. Environmental Protection Agency, PRESTO-EPA-CPG:
A Low-Level Radioactive Waste Environmental Transport
and Risk Assessment Code - Bocumentation and User's
Manual, EPA 520/1-87-026, Washington, B.C., 1987.
EPA87e U.S. Environmental Protection Agency, PRESTO-EPA-BRC: A
Low-Level Radioactive Waste Environmental Transport and
Risk Assessment Code - Bocumentation and User's Manual,
EPA 520/1-87-027, Washington, B.C., 1987.
EPA87f U.S. Environmental Protection Agency, PATHRAE-EPA: A
Performance Assessment Code - Bocumentation and User's
Manual, EPA 520/1-87-028, Washington, B.C., 1987.
EPA87g U.S. Environmental Protection Agency, An Accounting
Model - Bocumentation and User's Manual, EPA 520/1-87-
029, Washington, B.C., 1987.
EPA94 U.S. Environmental Protection Agency, "Estimating
Radiologic Cancer Risks," EPA report, EPA 402-R-93-076,
Washington, B.C., June,1994.
Et80 Etnier, E. L., "Regional and Site-Specific Absolute
Humidity Bata for Use in Tritium Bose Calculations,"
R-3
-------
Ev55
Ev68
Health Phys. 34 (2) :318-320, 1980.
Evans, R. D., "The Atomic Nucleus," Chapter 15, Section
8, pp. 490- 492, McGraw-Hill Book Co., 1955.
Evans, R. D., "X-Ray and Y-Ray Interactions," in
Radiation Dosimetry (F. H. Attix and W. C. Roesch,
editors), Vol. 1, Chapter 3, Academic Press, New York,
1968.
FiSOa Fields, D. E., and C. W. Miller, User's Manual for
DWNWND - An Interactive Gaussian Plume Atmospheric
Transport Model with Eight Dispersion Parameter
Options. ORNL/TM-6874 (Oak Ridge National Laboratory,
Oak Ridge, Tennessee), 1980.
FiSOb Fields, D. E., C. W. Miller, and S. J. Cotter,
"Comparisons of AIRDOSEPA Air Concentration Predictions
with Values from the Savannah River Laboratory Kr-85
Data Base," presented at fall meetings of American
Geophysical Union, San Francisco, California, Abstract
in EOS 61(46), p. 971, December 1980.
F181 Fields, D. E., C. W. Miller, and S. J. Cotter,
"Comparison of Observed and Predicted Sector-Averaged
Air Concentrations for Elevated Releases of Fluorescein
Particles," J. Air Poll. Control Association 31(8),
1981.
For77 Forsythe, G. E., M. A. Malcolm, and C. B. Moler,
Computer Methods for Mathematical Computations.
Prentice-Hall, Inc., Englewood Cliffs, New Jersey,
1977.
FoxSl Fox, D. G., "Judging Air Quality Model Performance,"
Bulletin # American Meteorological Society 62(5), 1981.
Gal84 Galpin, F. L., and G. L. Meyer, Overview of EPA's
Low-Level Radioactive Waste Standards Development
Program, 1984: Proceedings of 6th Annual Participants'
Information Meeting on DOE Low-Level Waste Management
Program, Denver, Colorado, September 11-13, 1984, CONF-
8409115, Idaho Falls, Idaho.
R-4
-------
Gau64
Ge73
Gia77
Gif62
Gif76
He80
Hi62
Ho74
Gautschi, W., and W. F. Cahill, "Exponential Integral
and Related Functions," in Handbook of Mathematical
Functions with Formulas, Graphs, and Mathematical
Tables (M. Abramowitz and I. A. Stegun, editors).
National Bureau of Standards, Washington, B.C., 1964.
Geraghty, J. J., D. W. Miller, F. Van Der Leechen, and
F. L. Troise, Water Atlas of the United States. Water
Information Center, Port Washington, New York, 1973.
Giardina, P. A., M. F. DeBonis, J. Eng, and G. L.
Meyer, Summary Report on the Low-Level Radioactive
Waste Burial Site, West Valley, New York (1963-1975) .
EPA-902/4-77-101, U.S. Environmental Protection
Agency, Region 11, Regional Office of Radiation
Programs, New York, New York, 1977.
Gifford, F. A., Jr., and D. H. Pack, "Surface
Deposition of Airborne Material," Nuc. Saf. 3(4), p.
76, 1962.
Gifford, F. A., "Turbulent Diffusion - Typing Schemes:
A Review," Nuc. Saf. 17(1), p. 68, 1976.
Healy, J. W., "Review of Resuspension Models," in
Transuranic Elements in the Environment (W. C. Hanson,
ed.), pp. 209-235. DOE/ TIC-22800 (Technical
Information Center/U.S. Department of Energy), 1980.
Hilsmeier, W. F. and F. A. Gifford, Jr., Graphs for
Estimating Atmospheric Dispersion. U.S. Weather Bureau
Report ORNL-545, Oak Ridge, Tennessee, 1962.
Hosker, R. P., Jr., "Estimates of Dry Deposition and
Plume Depletion Over Forests and Grasslands," in
Physical Behavior of Radioactive Contaminants in the
Atmosphere, pp. 291-309. Proceedings of a Symposium,
Vienna, Austria, November 12-16, 1973. STI/PUB/354,
International Atomic Energy Agency, Vienna, Austria,
1974.
Hu80
Hung, C.Y., "An Optimum Model to Predict Radionuclide
Transport in an Aquifer for the Application to Health
R-5
-------
Effects Evaluations," Modeling and Low-Level Waste
Management: An Interagecy Workshop, December 1-4, 1980,
Denver, Colorado.
Hu81 Hung, C. Y., "An Optimum Model to Predict Radionuclide
Transport in an Aquifer for the Application to Health
Effects Evaluation," in Proceedings, Modeling and Low-
Level Waste Management: An Interagency Workshop held
December 1-4, 1980, Denver, Colorado, (C. A. Little and
L. E. Stratton, Compilers), pp. 65-80. ORNL-821
(Department of Energy, Oak Ridge Operations Office, Oak
Ridge, Tennessee), 1981.
Hu83a Hung, C. Y., G. L. Meyer, and V. C. Rogers, Use of
PRESTO-EPA Model in Assessing Health Effects from Land
Disposal of LLW to Support EPA's Environmental
Standards: U.S. Department of Energy, Proceedings of
5th Annual Participants' Information Meeting on DOE
Low-Level Waste Management Program, Denver, Colorado,
August 30, 1983, CONF-8308106, Idaho Falls, Idaho.
Hu83b Hung, C. Y., "A Model to Simulate Infiltration of
Rainwater Through the Cover of a Radioactive Trench
Under Saturated and Unsaturated Conditions," in Role of
the Unsaturated Zone in Radioactive and Hazardous Waste
Disposal, edited by James W. Mercer, et al., Ann Arbor
Science, 1983.
Hu86a Hung, C.Y., "An Optimum Groundwater Transport Model for
Application to the Assessment of Health Effects Due to
Land Disposal of Radioactive Wastes," proceedings of
Nuclear and Chemical Waste Management, Vol. 6, pp. 41-
50, 1985.
Hu86b Hung, C.Y., "A Multi-Phase Leaching Model to Predict
the Leaching of Radionulides from a Radioactive Waste
Disposal Site," a paper presented at the Second
International Workshop on Leaching of Low- and Medium-
Level Waste Packages Under Disposal Conditions, October
13-16, 1986.
Hu87 Hung, C.Y., "User's Guide for INCPG Code --- A Code for
PRESTO-EPA-CPG Input File Preparation," Unpublished EPA
R-6
-------
Report, August 30, 1987.
Hu89 Hung, C.Y., "User's Guide for the SYSCPG Program ---A
PC Version of the PRESTO-EPA-CPG Operation System,"
Version 2.0, EPA Report, EPA/1-89-017, April 30, 1989.
Hu92 Hung, C.Y., "User's Guide for the SYSPOP Program --- A
PC Version of the PRESTO-EPA-POP Operation System,"
Version 1.0, EPA Report, 400-R-92-003, May 1, 1992.
ICRP77 International Commission on Radiological Protection,
"ICRP Publication 26, Annals of the ICRP 1(3), New
York, 1977.
ICRP79 International Commission on Radiological Protection,
"Limits for Intakes of Radionuclides by Workers," ICRP
Publication 30, Part 1. Annals of the ICRP 3(4), New
York, 1979.
Is59 Ishihara, T. and T. Takasao, "Fundamental Research on
the Unit Hydrograph Method and Its Application,"
Trans., JSCE No. 60, 1959.
Ko79 Kocher, D. C., Dose-Rate Conversion Factors for
External Exposure to Photon and Electron Radiation from
Radionuclides Occurring in Routine Releases from
Nuclear Fuel Cycle Facilities. Oak Ridge National
Laboratory, Oak Ridge, Tennessee. Report
ORNL/NUREG/TM-283, 1979.
Ko81 Kocher, D. C., Radioactive Decay Data Tables. DOE/TIC-
11026. (Technical Information Center, U.S. Department
of Energy), pp. 221, 1981.
Li81 Little, C. A., D. E. Fields, C. J. Emerson, G.
Hiromoto, Environmental Assessment Model for Shallow
Land Disposal of Low-Level Radioactive Wastes: Interim
Report. ORNL/TM-7943 (Oak Ridge National Laboratory,
Oak Ridge, Tennessee), 1981.
McC64 McCormick, J. M., and M. G. Salvador!, Numerical
Methods in FORTRAN, Prentice-Hall Englewood Cliffs,
R-7
-------
1964.
McE76 McElroy, A. D., S. Y. Chin, J. W. Nebgen, A. Aleti, and
F. W. Bennett, Loading Function for Assessment of Water
Pollution from Non-point Sources. USEPA Report EPA-
600/2-76-151, Midwest Research Institute, Kansas City,
Missouri, 1976.
McW79 McWhorter, D. B. and J. D. Nelson, Jour. Geotech. Eng.
Div. ASCE, pp. 105, 1317, 1979.
Mer83 Mercer, J. W., P. S. C. Rao, and I. W. Marine, Role of
the Unsaturated Zone in Radioactive and Hazardous Waste
Disposal, Ann Arbor Science Publishers, Ann Arbor,
Michigan, 1983.
MeySl Meyer, G. L., and C. Y. Hung, An Overview of EPA's
Health Risk Assessment Model for the Shallow Land
Disposal of LLW, Proceedings of an Interagency Workshop
on Modeling and Low-Level Waste Management, Denver,
Colorado, December 1-4, 1980, ORD-821, Oak Ridge
National Laboratories, Oak Ridge, Tennessee, 1981.
Mey84 Meyer, G. L., Modifications and Improvements Made to
PRESTO-EPA Family of LLW Risk Assessment Codes Based on
Recommendations of Peer Review, February 1984, U.S.
Environmental Protection Agency, Letter dated July 13,
1984, to Members of PRESTO-EPA Peer Review, February 7-
8, Airlie, Virginia: Washington, D.C., 1984.
Mi78 Miller, C. W., F. O. Hoffman, and D. L. Shaeffer, "The
Importance of Variations in the Deposition Velocity
Assumed for the Assessment of Airborne Radionuclide
Releases," Health Phys. 34(5), p. 730, 1978.
Mi81 Miller, C. W. and S. J. Cotter, "Comparison of
Observed and Predicted Normalized Air Concentrations
for Particles Released from a Height of 111 Meters,"
Third Joint Conference on Applications of Air Pollution
Meteorology, American Meteorological Society, Boston,
1981.
R-8
-------
Moo79 Moore, R. E., C. F. Baes III, L. M. McDowell-Boyer, A.
P. Watson, F. O. Hoffman, J. C. Pleasant, and C. W.
Miller, AIRDOS-EPA: A Computerized Methodology for
Estimating Environmental Concentrations and Dose to Man
from Airborne Releases of Radionuclides. ORNL-5532 Oak
Ridge National Laboratory, Oak Ridge, Tennessee, 1979.
Mor67 Morgan, K. Z. and J. E. Turner, Principles of Radiation
Protection, J. Wiley, New York, 1967.
Mu76a Murphy, B. D., "Deposition of S02 on Ground Cover,"
Proceedings of Third Symposium on Atmospheric
Turbulence, Diffusion, and Air Quality, American
Meteorological Society, Boston, Massachusetts, 1976.
Mu76b Murphy, B. D., The Influence of Ground Cover on the Dry
Deposition Rate of Gaseous Materials, Oak Ridge
National Laboratory, Oak Ridge, Tennessee, Report
UCCND/CSD-19, 1976.
NOAA79 National Oceanic and Atmospheric Administration,
National Climatological Summary Tables, National
Climatic Data Center, Asheville, North Carolina, 1979.
Ng68 Ng, Y. C., C. A. Burtoc, S. E. Thompson, R. K. Tandy,
H. K. Kretner, and M. W. Pratt, "Prediction of the
Maximum Dosage to Man from the Fallout of Nuclear
Devices," in Handbook for Estimating the Maximum
Internal Dose from Radionuclides Released to the
Biosphere, UCRL-50163, pt. IV, (Lawrence Radiation
Laboratory, Livermore, California), 1968.
0180 Olson, R. J., C. J. Emerson, and M. K. Nugesser,
Geocology: A County-Level Environmental Data Base for
the Conterminous United States. ORNL/TM-7351, Oak
Ridge National Laboratory, Oak Ridge,# Tennessee, 1980.
Pa61 Pasquill, F., "The Estimation of the Dispersion of
Wind-Borne Material," Meteorol. Mag. 90, p. 33, 1961.
Pa74 Pasquill, F., Atmospheric Diffusion, second ed., Ellis
Horwood, Ltd., Chichester, England, 1974.
R-9
-------
Pa76 Pasquill, F., The "Gaussian Plume" Model with Limited
Vertical Mixing, U.S. Environmental Protection Agency,
Research Triangle Park, N.C. Report EPA-600/4-76-042,
1976.
Pr81 Prudic, D. E., "Computer Simulation of Groundwater
Flow at a Commercial Radioactive Waste Landfill Near
West Valley, Cattaraugus County, New York," in C. A.
Little and L. E. Stratton (compilers), Modeling and Low
Level Waste Management: An Interagency Workshop, pp.
215-248, ORO-821, Department of Energy, Oak Ridge
Operations Office, Oak Ridge, Tennessee, 1981.
Ro84 Rogers, V. C., An Update on Status of EPA's PRESTO
Methodology for Estimating Risks from disposal of LLW
and BRC Wastes, U.S. Dept. of Energy, Proceedings of
6th Annual Participants' Information Meeting on DOE LLW
Management Program, Denver, Colorado, September 11-
13,1984, CONF-8409115, Idaho Falls, Idaho.
Ro87 Rogers, V. and Shuman R. "Modification of the PRESTO-
EPA-POP Code to Simplify Dose Calculations," a RAE
Report prepared for U.S. Environmental Protection
Agency, RAE-8706/6-2, December 23, 1987.
Se80 Sehmel, G. A., "Particle and Gas Dry Deposition: A
Review," Atmos. Environ. 14, p. 983, 1980.
Shi76 Shinn, J. J., N. C. Kennedy, J. S. Koval, B. A.
Cless, and W. M. Porch, "Observations of Dust Flux in
the Surface Boundary Layer for Steady and Non-Steady
Cases," in Atmospheric-Surface Exchange of Particulate
and Gaseous Pollutants, ERDA Symposium Series No. 38,
Richland, Washington, September 4-6, 1974, R. J.
Enselmann and G. A. Sehmel coordinators, pp. 625-637,
NTIS Report CONF-740921, 1976.
Sho82 Shor, R. W., C. F. Baes 111, and R. D. Sharp,
Agricultural Production in the United States by County:
A Compilation of Information from the 1974 Census of
Agriculture for Use in Terrestrial Food-Chain Transport
and Assessment Models. ORNL-5768, Oak Ridge National
R-10
-------
Laboratory, Oak Ridge, Tennessee, 1982.
Si66 Singer, 1. A. and M. E. Smith, "Atmospheric Dispersion
at Brookhaven National Laboratory," Int. J. Air Water
Pollut. 10:125, 1966.
S168 Slade, D. H. ed., Meteorology and Atomic Energy, U.S.
Atomic Energy Commission Report TID-24190, 1968.
Sm82 Smith, J. M., et al., Environmental Pathway Models for
Estimating Population Health Effects from Disposal of
High-Level Radioactive Waste in Geologic Repositories,
EPA Report EPA 520/5-80-002, 1982.
Su81 Sullivan, R. E., N. S. Nelson, W. H. Ellet, D. E.
Dunning, Jr., R. W. Leggett, M. G. Yalcintas, and K.
F. Eckerman, Estimates of Health Risk from Exposure to
Radioactive Pollutants, ORNL/TM-7745, Oak Ridge
National Laboratory, Oak Ridge, Tennessee, 1981.
Sy81 Sykes, J. F., S. Soyupak, and G. J. Farquhar, "Modeling
of Leachate Organic Migration and Attenuation in
Groundwater Below Sanitary Landfills," Water Resources
Research, 18, 1, pp. 135-145, 1981.
USDA61 U.S. Department of Agriculture, "A Universal Equation
for Predicting Rainfall-Erosion Losses," U.S. Agr. Res.
Serv., Special Report 22-26, 1961.
USDC77 U.S. Department of Commerce, 1974 Census of
Agriculture, Bureau of the Census, Agriculture
Division, Washington, D.C., 1977.
NRC77 U.S. Nuclear Regulatory Commission, "Regulatory Guide
1.109: Calculation of Annual Doses to Man from Routine
Releases of Reactor Effluent for the Purpose of
Evaluating Compliance with 10 CFR Part 50," Appendix I,
R-ll
-------
U.S. Nuclear Regulatory Commission, Washington, D.C.,
1977.
Vo77 Vogt, K. J., "Empirical Investigations of the Diffusion
of Waste Air Plumes in the Atmosphere," Nuclear
Technology 34:43-57, 1977.
We76 Weast, R. C., Handbook of Chemistry and Physics, 57th
Edition, Chemical Rubber Co., Cleveland, Ohio, 1976.
Wi65 Wischmeier, W. H. and D. D. Smith, "Predicting
Rainfall-Erosion Losses on Cropland East of the Rocky
Mountains," Agricultural Handbook 282, USDA,
Agriculture Research Service, 1965.
R-12
------- |