ML20046C806
| ML20046C806 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/1993 |
| From: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20046C699 | List: |
| References | |
| REF-WM-3 NUDOCS 9308120200 | |
| Download: ML20046C806 (43) | |
Text
-
DOSE ASSESSMENT FOR DISPOSAL OF RADIOLOGICALLY CONTAMINATED SEWER SLUDGE FROM ERWIN, TENNESSEE June 1993 I
i I
U.S. NUCLEAR REGULATORY COh1 MISSION OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS DIVISION OF LOW LEVEL WASTE MANAGEMENT AND DECOMMISSIONING WASHINGTON, D.C.
Enclosure 9308120200 930729 f'
PDR WASTE
?s' "
WM-3 PDR i
i t
o TABLE OF CONTENTS Pace Number
- 1. INTRODUCTION 1
- 2. BACKGROUND INFORMATION 2
2.1 Disposal Options 2
2.2 Radiological Characteristics 4
2.3 Disposal Site Characteristics 5
- 3. RESRAD RUNS 6
4.RESULTS 7
l 4.1 Johnson City Landfill Dose Assessment Results 7
4.2 Carter County Landfill Dose Assessment Results 9-4.3 Assessment of Dose to Workers From Clean-up of Old Digester 10
- 5. CONCLUSIONS 17
- 6. REFERENCES 18
)
s t
m l
APPENDICES' APPENDIX A1:
RESRAD COMPUTER OUTPUT FOR TOHNSON CITY LANDFILL USING SOURCE-TERM SCENARIO 1 (TEXT AND GRAPHIC OUTPUT)
APPENDIX A2:
RESRAD COMPUTER OUTPUT FOR JOHNSON CITY LANDFILL USING SOURCE-TERM SCENARIO 2 (TEXT AND GRAPHIC OUTPUT)
APPENDIX B1:
RESRAD RUN OUTPUT FOR CARTER COUNTY LANDFILL USING SOURCE-TERM SCENARIO 1A (TEXT AND GRAPHIC OUTPUT)
APPENDIX B2:
RESRAD RUN OUTPUT FOR CARTER COUNTY LANDFILL USING SOURCE-TERM SCENARIO 1B (TEXT AND GRAPHIC OUTPUT)
APPENDIX B3:
RESRAD RUN OUTPUT FOR CARTER COUNTY LANDFILL USING SOURCE-TERM SCENARIO 2A (TEXT AND GRAPHIC OUTPUT)
APPENDIX C:
RESRAD RUN FOR EXTERNAL GAMMA DOSE OUTPUT FOR OCCUPATIONAL WORKER INVOLVED IN THE CLEANUP OF THE OLD DIGESTER (
SUMMARY
OF OUTPUT ONLY) r i
P
'These are large volume outputs, they have been provided to the State of Tennessee separate from this report.
s i
L1rf CF TABLES Pace Number-TABLE 1: IMPORTANT SITE-SPECIFIC PARAMETERS USED i
IN RESRAD MODEL FOR JOHNSON CITY REGIONAL LANDFILL 20 TABLE 2: IMPORTANT SITE-SPECIFIC PARAMETERS USED IN RESRAD MODEL FOR CARTER COUNTY /ELIZABETHTON LANDFILL 21 TABLE 3: AVERAGE RADIONUCLIDE CONCENTRATIONS FOR ALL SLUDGE LAYERS CONSIDERING i
WEIGHT FRACTIONS 22 TABLE 4: RADIONUCLIDE CONCENTRATIONS OF SAMPLES No. 12271, 12272, 12273 AND THE MEAN CONCENTRATIONS OF THE SCUM LAYER 23 TABLE 5:
SUMMARY
OF DOSE RESULTS.FOR JOHNSON CITY LANDFILL SOURCE-TERM SCENARIO 1 24
}
TABLE 6:
SUMMARY
OF DOSE RESULTS FOR JOHNSON CITY LANDFILL SOURCE-TERM SCENARIO 2 25 TABLE 7:
SUMMARY
OF DOSE RESULTS FOR CARTER COUNTY /ELIZABETHTON, TN, LANDFILL FOR SOURCE-TERM SCENARIOS 1-A AND A-B 26 TABLE 8:
SUMMARY
OF DOSE RESULTS FOR CARTER
'l COUNTY /ELIZABETHTON, TN, LANDFILL 27 TABLE 9:
SUMMARY
OF DOSE RESULTS FOR EXPOSURE OF WORKER INVOLVED IN THE CLEANUP ACTIVITY OF THE DIGESTER 28 l
9 f
I l
I I
l
FIGURES Pace Number FIGURE 1: A SCHEMATIC DIAGRAM SHOWING DIFFERENT LAYERS ACCUMULATED IN THE OLD DIGESTER 29 FIGURE 2: JOHNSON CITY TN, LANDFILL SITE LAYOUT SHOWING POTENTIAL SLUDGE DISPOSAL AREAS 30 FIGURE 3: CARTER COUNTY /ELIZABETHTON TN, LANDFILL SITE LAYOUT SHOWING POTENTIAL SLUDGE DISPOSAL AREAS 31 FIGURE 4: TOTAL DOSE -- ALL ISOTOPES AND PATHWAYS SUMMED FOR JOHNSON CITY, TN LANDFILL (SCENARIO 1) 32 FIGURE 5: TOTAL DOSE -- ALL ISOTOPES AND PATHWAYS SUMMED TOR JOHNSON CITY TN, LANDFILL (SCENARIO 2) 33 FIGURE 6: TOTAL DOSE -- ALL ISOTOPES AND PATHWAYS SUMMED FOR CARTER COUNTY /ELIZABETHTON TN, LANDFILL FOR SCENARIO 1A 34 FIGURE 7: TOTAL DOSE -- ALL ISOTOPES AND PATHWAYS SUMMED FOR CARTER COUNTY /ELIZABETHTON TN, LANDFILL i
FOR SCENARIO IB 35 FIGURE 8: TOTAL DOSE -- ALL ISOTOPES AND PATHWAYS SUMMED FOR CARTER COUNTY /ELIZABETHTON TN, LANDFILL FOR SCENARIO 2 36 FIGURE 9: TOTAL DOSE -- ALL ISOTOPES AND DIRECT GAMMA EXPOSURE PATHWAY FOR OCCUPATIONAL WORKER INVOLVED IN THE CLEANUP OF THE OLD DIGESTER' 37 PLATES PLATE 1: A PANORAMIC VIEW OF THE OLD DIGESTER 38
i i
DOSE ASSESSMENT OF DISPOSAL OF RADIOLOGICALLY CONTAMINATED SEWER SLUDGE FROM ERWIN, TENNESSEE i
- 1. INTRODUCTION Nuclear Fuel Services (NFS) and its predecessors have operated a fuel cycle facility near Erwin, TN since 1958. The NFS facility is licensed by the Nuclear Regulatory Commission for possession and use of source and special nuclear material. Over the last three decades, NFS discharged allowable l
quantities of radioactive materials in liquid effluents to the public sanitary l
sewer system of the city of Erwin, TN.
Since 1962, the city of Erwin i
operated a publicly owned treatment works (POTW) to treat sanitary sewerage, including the effluent from the NFS facility.
In the course of sampling POTWs in Tennessee in 1986, the Tennessee Department of Environment and Conservation (TDEC) found elevated concentrations of enriched uranium (700-800 pCi/g) and other radionuclides in the Erwin POTW.
The sewer sludge contaminated with the uranium was emptied from the old digester and used as backfill on-site. The old digester is pictured in Plate.
1.
Additional contaminated' sludge was applied to farmlands in the Erwin area as a fertilizer in the mid-1980s. During the period 1986-1988, approximately 3
29,000 ft of additional contaminated sludge accumulated in the old digester, s
where it has been held pending instructions from TDEC and NRC on acceptable disposal methods for the contaminated sludge.
Based on available records, NRC believes that the effluents containing the uranium were discharged in accordance with NRC requirements in 10 CFR Part 20 (520.303).
It appears that the uranium was inadvertently concentrated in the sewer sludge at the Erwin POTW as a result of treatment and processing of the waste water to remove solid materials from the sewer.
Since the elevated concentrations of uranium were initially detected in the sludge, NFS has i
significantly reduced.its discharges of uranium to the sanitary sewer.
3 The sludge in the old digester became stratified during operations with the lighter solids floating to the top of the tank and the denser materials sinking to the bottom. Figure I presents a schematic cross section diagram showing different layers of sludge in the digester, including crust layer, scum layer, slurry layer, slurry and grit layer, and grit layer.
Because of the physical properties of the sludge,'most of the sewer sludge should be acceptable for. disposal in sanitary landfills without extensive processing.-
In'1991, NRC contracted with the Oak Ridge Associated Universities (0RAU) to analyze the sludge in the old digester to determine the extent of radiological contamination. ORAU (0RAU 91/H-22; Ref.1) found total uranium concentrations,-in composite samples taken from different layers in the
' digester, in the range of 299 to 768 pCi/g. As a result of the elevated levels of uranium in the sludge, NFS, Erwin Utilities, TDEC, and the NRC have cooperated in the assessment of disposal alternatives for the: contaminated
-i sludge.
1i
This study primarily assesses potential radiological impacts associated with disposal of the contaminated sludge at two landfill sites:
the Johnson City, TN, regional sanitary landfill, and the Carter County /Elizabethton, TN sanitary landfill.
In a previous study in 1991, the NRC staff assessed potential radiological impacts associated with land application of the contaminated sludge on approximately 100 acres of agricultural lands in the vicinity of Erwin, Tennessee (Ref. 3).
In the 1991 assessment, NRC staff assumed the sludge (10,000 lbs/ acre) would be spread and mixed into the top six inches of the soil. Using the RESRAD computer code and reasonably-conservative assumptions, the NRC staff calculated a maximum total effective i
dose equivalent from all isotopes and all pathways to an onsite resident farmer less than 1 mrem /yr.
As an alternative to land application of the contaminated sludge, the NRC staff has also assessed the radiological impacts potentially associated with disposal of the sludge in sanitary landfills.
In the firs scenario, all the sludge layers in the old digester (approximately 29,000 ft}) would be disposed of at the landfill site.
In the second scenario, the NRC assumed that only 3
the scum layer (upper 8 ft of the sludge; approximately 12,889 ft ) would be disposed of at the landfill site. Assuming that the potential doses to members of the public are acceptably low and that disposal of the sludge is not otherwise restricted (e.g., controlled as a hazardous waste), the city of 3
Erwin coulp)then dispose either the scum layer (12,889 ft ) or all sludge (29,000 ft at either landfill site over a period of several months to a year.
This report assesses potential doses associated with the disposal of the f
contaminated sludge at the landfill sites using the computer code RESRAD.
Staff from the Tennessee Department of Health and Environment (TDHE) provided information about the environmental and design characteristics of the Johnson City /Bowsar Ridge landfill and the Carter County sanitary landfill (Ref. 2).
NRC staff assumed radiological characteristics of the contaminated sludge based on ORAU report 91/H-22.
In addition, the report also evaluates potential exposures to workers who may be involved in removing, processing, and disposing of the contaminated sludge.
I
- 2. BACKGROUND INFORMATION 2.1 Disposal Options Two primary disposal options have been considered in this study for disposal of the contaminated sludge in the old digester at the Erwin POTW. The first option involves the disposal of either all sludge material (Source-term scenario IA) or the scum layer only (Source-term scenario 2A) at the Johnson City, TN, Regional landfill. The second option involves disposal of either all sludge material (Source-term scenario IB) or the scum layer only (Source-term scenario 28) at the Carter County /Elizabethton, TN, Municipal landfill.
The first option assumes the contaminated sludge will be disposed of in a fixed area over a period of several_ months to a year. The second option, however, assumes that the sludge will be disposed in municipal waste cells over a period of three or six months, t
2 p
E
.t t
Considering the first landfill disposal option (Johnson City landfill),
the contaminated sludge would be disposed of along with other municipal-waste in a portion of the existing landfill covering an area of about 2
68,000 m. This area represents the total area of the anticipated landfill (three areas marked on Figure 2) where municipal waste will be disposed of over the next cycle of years. The depth of the landfill in i
these areas was assumed to be about 3.7 m, which is the same depth of i
the typical daily disposal cell at the Johnson City landfill. Thus, the total volume of landfill available for disposal of both municipal waste and contaminated sludge would be 249,000 m.
l Two source-term scenarios were assumed in the current assessment:
j (1) The first pource-term scenario assumes that the total sludge volume 3
(29,000 ft or 821.2 m ) will be disposed of in the landfill area i
over a period of sever al months to a year, thereby, assuming homogeneous mixing of the sludge wi Assuming a municipa] waste density of 0.6 g/cm}h municipal waste.
and a typical sludge density of l
1.0 g/cm, the mixing ratio (sludge : municipal waste) would be 1:182 by weight.
In other words, the radionuclide concentrations in the landfill cell after mixing would be 182 times lower than that of the sludge due to mixing with uncontaminated (in terms of radiological contamination only) municipal waste and interim cover material.
i (2) The second source-term scenario assumes that only the scum layer of the contaminated sludge will be disposed of in the landfill with a dilution factor of 1:409 by weight because of the smaller total volume of the scum layer alone.
Considering the second landfill disposal option (Carter County /Elizabethton landfill), the contaminated sludge [either the i
3 29,000 ft volume which includes all sludge layers (scenario 1) or the 12,889 ft volume which only includes the scum layer (scenario 2)] was assumed to be disposed of at the landfill site over a three-to six-month period. The disposal area was calculated from the volume of municipal waste to be disposed of at the landfill.
It was assumed that 150 short tons of municipal waste will be disposed pn daily basis. This t
3 volume corresponds to a daily cell volume of 300 yd (i.e. 2 yd for i
each short ton of municipal waste). The thickness of each daily cell wasassumpdtobe10ft(3m). The density of the sludge was assumed to
.i be 1 g/cm. All sludge volume, for each scenario, was assumed to be disposed of along with municipal waste on daily basis for either 3 months or 6 months. The sludge disposal conditions in the Carter County landfill for each scenario are summarized below:
(1) The first source term scenario assumes all sludge material will be disposed of on a daily basis in the landfill cells over a 3-month or 6-month period.
(1-a)
'Considering a 3-month period, the sludge will be mixed
)
3 i
[
l
homogeneously with municipal waste in 90 cells.
In this case, the dilution factor was calculated from the total volume of municipal waste to be disposed of for the 90 days period (12,247 metric tons). The volume of sludge in the 3
digester (29,000 ft ) is equivalent to 821 metric tons (assuming a density of I g/cm ).
Thus, the dilution factor was calculated at 1:15 by weight. The disposal area was calculated from the total volume of waste assuming a density 3
of 0 6 g/cm for the municipal waste and a density of 1.0 g/cm$ for the sludge. The thickness of the disposal area was assumed to be 10 ft (3 m)j The disposal area was then estimated to be about 7,000 m.
j 3
(1-b)
Assuming the bulk sludge volume (29,000 ft ) will be disposed during a 6-month period, the sludge will be mixed with municipal waste in 180 daily cells.
In a similar manner as in (1-a), the dilution factor was calculated at a ratio of 1:30 gy weight, and the area was calculated at about 14,000 m.
(2) The second source term scenario assumes only the scum layer will be disposed of at the Carter County landfill.
In a similar approach, as in source term spenario 1, the sludge from the scum layer with a volume of 12,889 ft will be disposed of over either a 3-month or 6-month time periods.
(2-a)
In this source term scenario, the scum layer will be disposed of during a 3-month period; thus, the sludge will be mixed homogeneously with municipal waste in 90 daily cells. The dilution factor was calculated for this disposal option at a ratio of 1:33.5 by weight, and the disposal area after completion of disposal activities was calculated at 7,000 m. All assumptions concerning waste densities and volume of cell were the same as in scenario 1-a above.
(2-b)
This disposal option involves disposal of the scum layer at the site over a period of 6 months.
Thus, the sludge will be mixed with municipal waste in 180 daily cells over this period of time. The dilution factor was calculated at a ratio of 1:67 by weight, and the arpa after completion of disposal was calculated at 14,000 m.
t 2.2 Radiological Characteristics 1
The radiological characteristics of the sludge were estimated from the l
datag38resenj'edirg"Ref.1. ge sludge contains elevated levels of 23'U, 23s 232 U,
0, Pu, Am, and Th. The elevated levels of Th were identified in a supplemental ORAU analysigprovideg8to NRC on August 13, 1991 (Ref. 4). Two other radionuclides, Ra and Pu, were also j
detected in the sludge, but not at levels significantly different than background levels.
[
4
[
l t
The material that would be disposed of at the landfill for the first scenario is represented by the five layers namely: scum, slurry, thick sludge, sludge with grit, and the grit layer. The scum layer is about 8 ft thick representing 44.44% of the bulk sludge volume. The concentration of radiological contaminants in this layer was derived by averaging concentrations of samples 12271, 12272,.and 12273. The slurry layer is 2 ft thick, thus, comprising 11.11% of the total sludge volume.
The radiological characteristics of this layer were derived from the data of sample 12274 (Ref.1).
Layers 3 (thick sludge), 4 (sludge with grit), and 5 (grit) are each 2 ft thick; each layer is represented by sample 12276, 12277, and 12278, respectively.
For the radiological characteristics of each sample, see Table 2 of Ref.1. The average radionuclide concentrations for the bulk sludge material was calculated from the weighted average concentration of each layer (i.e., average r
concentration of the layer multiplied by its weight fraction). The i
average weighted concentration of the sludge was then divided by the dilution factor corresponding to each source term scenario. The mean i
radionuclide concentrations are summarized in Tables 3 and 4 with and without dilution for the two source term scenarios.
2.3 Disposal Site Characteristics 2.3.1 Johnson City Regional Landfill Site Characteristics l
TDHE provided the disposal site characteristics to the NRC (Ref. 2).
l NRC staff visited the landfill site in 1992.
The contaminated sludge in the landfill was assumed to represent the contaminated zone in the i
RESRAD model.
In both source term scenarios, the landfill area containing the sludge was assumed to have no cover.
The thickness of i
the contaminated zone in both scenarios was assumed to be 3.66 m.
All i
remaining site characteristic parameters should be the same for both scenarios.
l s
The unsaturated zone beneath the cell is assumed to be a homogeneous layer, 4 m thick with a hydraulic conductivity of 3 m/yr. This layer was assumed to be a mixture of sand, silt, and clay.
The depth to the water table beneath the cell was assumed to be 4 m from the bottom of the cell, as a conservative assumption; no water table drop rate was assumed in the RESRAD model.
The maximum hydraulic conductivity of the aquifer (saturated zone) was calculated, from the data provided by TDHE, to be about 2,800 m/yr.
This value is considered rather high.for the aquifer given the lithologic description provided for the unit. Thus, NRC staff selected a value of 1,000 m/yr as a more reasonable value of the hydraulic j
conductivity of the aquifer. Nevertheless, NRC conducted a sensitivity analysis for this parameter by evaluating doses of a range of +/- 100%,
which included the value provided by TDHE.
RESRAD default values were selected for the distribution coefficients of radionuclides present in the waste. Sensitivity analysis (+/-;100%) was also conducte distribution coefficients for the major radionuclides (i.e., g'for the O and 5
1 l
}
j n2Th).
Table I lists the important site-specific input parameters used in the RESRAD model for the landfill cell. All input parameters in the code are summarized on pages 11-16 of Appendix A.
2.3.2 Carter County /Elizabethton Sanitary Landfill Site Characteristics TDHE also provided the disposal site characteristics to the NRC staff for the Carter County site (by transmitting information to NRC by facsimile). Addition information was collected from the operator of the Carter County landfill during a site visit by the NRC staff.
In both source term scenarios, the landfill area was assumed to have a clay 4
cover of 1 m thick. The thickness of contaminated zone for both source term scenarios was assumed to be 3 m.
The unsaturated zone beneath the cell was assumed to be a homogeneous layer of silt and clay of 30.5 m thick with a hydraulic conductivity of 0.3 m/yr. The depth to the water table beneath the cell was assumed to be 30.5 m from the bottom of the cell.
j The underlying aquifer is the Shady Dolomite, in which most of the groundwater flow occurs through conduits and solution zones as secondary j
permeability. The hydraulic conductivity of the saturated zone was
^
calculated at 315 m/yr.
P Table 2 lists the important site-specific input parameters used in the l
RESRAD model for the Carter County landfill site.
All input parameters in the code are summarized on pages 9-13 of the dose assessment summary report attached in Appendix A.
3.
RESRAD RUNS i
(
In the current dose assessments, NRC staff used version 4.33 of the RESRAD code.
The RESRAD model assumes a family-farm exposure scenario. Thus, it is assumed that a family will move onto the disposal (landfill) site and build a residence, after its release for unrestricted use, and that members of the family could conceivably receive a radiation dose through: direct radiation exposure, inhalation of resuspended dust, inhalation of radon and decay i
products, ingestion of food from crops grown in the contaminated soil, ingestion of milk and meat from livestock raised in the contaminated area, ingestion of fish from a contaminated nearby pond, and ingestion of contaminated water from a well at the site.
The resident family is also assumed to drill a well at the site boundary, to draw water for irrigation, drinking, bathing, and watering farm animals. The water is assumed to be
[
drawn from the aquifer below the site at the downgradient edge of the contaminated zone.
Estimates of the projected doses to potential future residents were developed
[
based on multiple computer runs.
The simulations included all nine potential exposure pathways (external radiation, dust inhalation, plant ingestion, meat i
ingestion, milk ingestion, aquatic food ingestion, drinking water, radon, and 6
4 Y
i soil ingestion). The runs were executed for both of the source term scenarios (disposal of all sludge layers and disposal of scum layer only) for both i
landfill sites. The NRC staff also conducted limited sensitivity analyses for five input parameters: a) the hydraulic conductivity of the contaminated zone b) the hydraulic conductivity of the unsaturated zone, c) the hydraulic i
conductivity of the saturated zone, d) ge distribution coefficient of 23'U, t
and e) the distribution coefficient of Th. These parameters were selected based on previous experience in conducting sensitivity analysis for i
groundwater transport simulations for similar types of sites.
The family-farm resident scenario mentioned in Section_1 is based on a group of conservative assumptions.
For example, the location of the water well, at the site boundary, and the water-use fraction (100% contaminated water usage) are rather conservative assumptions. The food consumption (100% grown or raised on contaminated soil and water) is another conservative assumption in i
this scenario.
The NRC staff consider that it would be unlikely for future residents to grow crops, graze livestock, and live on soils that would otherwise be littered by plastics and other durable materials.
Infiltrated i
rain-and irrigation-waters are assumed to leach uranium from the contaminated sludge in the landfills. The leachates then infiltrate through-i the unsaturated zone below the cell directly to the aquifer.
In addition to the conservative assumptions in the resident scenario, several input parameters were also conservatively selected.
The simulations did not consider the effects of liners or other engineered barriers above, within, or beneath the landfill cell. The distribution coefficients were selected conservatively. However, some. credit was taken for sorption by the clay in the unsaturated zone. Therefore, the mobilization of radionuclides was probably overestimated.
In order to show the influence of retardation factors (or distribution coefficients) on the overall projected doses, the NRC staff conducted sensitivity analysis for this parameter. The hydraulic conductivity of the unsaturated zone was also selected conservatively.
Scenario initiation t
time was also assumed to be the time of waste placement.
4.
RESULTS 4.1 Johnson City Landfill Dose Assessment Results d
The results from the RESRAD modeling be viewed cautiously, taking into account the embedded assumptions in the code, the site-specific and default input parameters, and other limitations of the assessment (e.g., the assumption of a j
homogeneous mixing condition of the contaminated sludge with the-disposed municipal waste in the landfill). The objectives of this radiological dose assessment modeling are to project potential doses to a maximum reasonably expued individual or critical group of the public.. In many cases, this modeling and scenario approach appears to take an ultra conservative approach i
in defining the maximally exposed individual. Nevertheless, the modeling 2It should be noted that the materials of the Faking are silty clays with' some chert.
7 I
I 4
provides valuable insights into potential radiological doses for decision makers and regulators to consider in estimating the potential impacts associated with disposal of the contaminated sludge.
The complete dose assessment results for source term scenarios "1" and "2" for each landfill site are presented in Appendices Al and A2. A summary report of 1
the RESRAD dose analysis results for each individual radionuclide and pathway are provided on pages 16-28 of Appendices Al and A2. Several plots were also produced (see Appendices 81 and B2) to illustrate dose fractions originating from different pathways and to demonstrate dose accumulation or decay with time. The sensitivity analyses conducted for five parameters are also illustrated in the dose vs. time figures. Doses resulting from various radionuclides (3'O and "2Th) are also shown in these figures. Appendices B1 and B2 present all figures and diagrams produced in RESRAD runs for each of the landfill sites using source term scenarios "1" and "2," respectively.
The results of RESRAD analysis, using the initial radionuclide inventory present in the bulk sludge in the landfill areas shown on Figure 1 (after mixing), indicate a total effective dose equivalent to a maximally exposed individual of about 1 mrem /yr at about 460 years. The maximum total doses at different times from 0 to 460 years are given below:
Time (y) 0 10 30 100 300 460 Projected Doses for 0.6 0.7 0.8 0.7 0.6 1.1 Scenado I (mrem /yr)
The results of runs obtained for Source Term Scenario 2 (scum layer only) indicated a total dose to a maximally exposed individual of about 0.45 mrem /yr at the same time (460 years) as Source Term Scenario 1.
The maximum total doses at different times from 0 to 460 years for Scenario 2 are also presented below:
Time (y) 0 10 30 100 300 460 Projected Doses for 0.3 0.3 0.3 0.2 0.2 0.45 Scenado 2 (mrem /y) l The total dose from all pathways other than the groundwater pathway nearly stabilizes, around 0.8 mrem /y for Scenario 1 and around 0.3 mrem /y for Scenario 2 within about 20 years after sludge disposal in the landfill area.
After 400 years, doses increase to reach their maxima for both scenarios at about 460 years. This increase is mainly due to the projected arrival of d'U-contaminated groundwater at the well at the boundary of the site.
1' Two radionuclides, "U and "#Th, contributed over 90% of the projected total 2"U,themajordosefractioncamefromthewater-dependent dose.
For 2
pathways, whereas for Th, the major dose fraction resulted from water-independent (mostly direct radiation and dust inhalation) pathways.
For 8
i i
B
Source Term Scenario 1, considering the dose at 30 years agan example, 23'u
^
contributed nearly 0.4 mrem /yr from all pathways, whereas Th contributed around 0.4 mrem /yr.
The results of the sensitivity analyses indigted that changing the distribution coefficient, K, by i 100% for Th did not significantly change thegseestimates(upto16,000y). On the other hand, varying the K value d
for U by 100% caused the time of the peak dose to occur after nearly 275 years for -100% sensitivity analysis and after nearly 1000 years for +100%
sensitivity analysis. This time reflects the period of time required for the contaminated groundwater to arrive at the well. Changing the hydraulic conductivity of the contaminated and the unsaturated / uncontaminated zones by i 100% did not cause any significant changes in the dose values. On the other hand, varying the hydraulic conductivity of the saturated zone, by i 100%,
varied the estimated doses by a factor of 1 2 times.
Figures 2 and 3 summarize the doses summed for all isotopes for water-t independett and water-dependent pathways for Scenarios I and 2, respectively.
4.2 Carter County Landfill Dose Assessment Results The complete dose assessment results for Source Term Scenarios 1 and 2 are presented in Appendices Al and A2. A summary report of the RESRAD dose analysis results for each individual radionuclide and pathway are provided on pages 16-28 of Appendices Al and A2. Several plots were also produced (see Appendices B1 and B2) to illustrate dose fractions originating from different l
pathways and to demonstrate dose accumulation or decay with time. Appendices B1 and B2 presents all figures and diagrams produced in RESRAD runs for each i
of the landfill sites using Source Term Scenarios. and 2, respectively.
The results of RESRAD analysis for disposal of all sludge layers in the Carter County landfill site considering 3-month (1-a) and 6-month (1-b) disposal period indicate a total dose to a maximally exposed individual of about 17.5 and 9.0 mrem /yr, respectively at about 3700 years for both options. The maximum total doses at different times from 0 to 3700 years are given below:
l l
Time (y) 0 100 300 1000 3700 Estimated Total Dose For 0.009 0.008 0.31 4.2 17.5 Option 1-a (mrem /y)
Estimated Total Dose For 0.005 0.004 0.16 2.1 9.0 Option 1-b (mrem /y)
The results of runs obtained for Source Term Scenario 2 (scum layer only),
l considering disposal over a 3-month (2-a) and 6-month (2-b) period indicate a total dose to a maximally exposed individual of about 8.1 and 4.0 mrem /yr, respectively at about 3700 years for both options. The maximum total doses at l
different times from 0 to 3700 years for Scenario 2 are also presented below i
9 I
i
.l l
\\
1 Time (y) 0 100 300 1000 3700 Estimated Total Dose for 0.003 0.003 0.11 0.67 8.1 Option 2-a (mrem /y )
Estimated Total Dose for 0.002 0.001 0.05 0.33 4.0 Option 2-b (mrem /yr) i The total dose is insignificant for all disposal options in this landfill site for more than 1000 years. The dose starts to increase to a maximum level of 4.5 mrem /y and 2.5 mrem /y for scenarios 1-a and 1-b, respectively, and around 0.8 mrem /y and 0.4 mrem /y for scenario 2-a and 2-b, respectively, after 1,000.
After 3,000 years, the doses further increase to reach their maxima for both scenarios at about 3,700 years. This increase is mainly due to the projected arrival of 23'U-contaminated groundwater at the well at the boundary of the site. After nearly 4,000 years, the estimated doses drop again to less than 1 mrem /y and increase again sharply at 8,000 years to reach a level of 7.5 and j
3.75 mrem /yr for Scenarios 1-a and 1-b and a level of 4 and 2 mrem /y for Scenarios 2-a and 2-b.
Two radionuclides 23'O and 232Th contributed over 85% of the total dose.
For 23'U,yhemajordosefractioncamefromthewater-dependentpathways,whereas for Th, the major dose fraction resulted from water-independent (mostly direct radiation and dust inhalation) pathways.
For Source Term Scenario 1, considering the dose at t - f000 years, 23'u contributed less than 0.2 mrem /yr 2
from all pathways, whereas Th contributed around 3.5 mrem /yr.
Figures 4, 5, 6, and 7 summarize the doses summed for all isotopes for water-independent and water-dependent pathways for scenarios 1-a, 1-b, 2-a, and 2-b, respectively for the Carter County landfill disposal site.
4.3 Assessment of Dose to Workers From Clean-up of the Sludge Digester 4.3.1 Radiological Exposure Pathways The method of removal of the sludge and decontamination of the sludge digester involves extraction of the contaminated sludge by a high-pressure water spray and processing the sludge in a filter press to reduce the water content. After processing the sludge, it would be hauled by truck to the landfill for disposal. When most of the sludge I
has been removed, workers would enter the digester and use scraping tools and high pressure hoses to remove the sludge layer attached on the inner surface of the digester wall. While in the digester, the workers will be exposed to low levels of radiation from direct gamma radiation
- and inhalation.
Exposures to workers in the digester are expected to bound the upper range of potential exposures because the work would take i
place within a confined space and in close proximity to the contaminated 6
sludge. Other exposures to workers while processing the sludge outside l
of the digester (e.g., at the filter press), hauling the sludge to the landfill, or placing the sludge at the landfill are expected to be less 10
than potential exposures that may occur within the digester.
The conceivable radiological exposure pathways for workers inside the digester are as follows Direct gamma radiation emitted from the radionuclides present in the sludge and from their decay products.
Inhalation of radon (zzzRn) and thoron (zzoRn) and their decay
=
products.
Inhalation of resuspended aerosolized water droplets mixed with air and dust and contaminated with the sludge material, including all i
radionuclides listed in Table 3.
4.3.2 Assumptions Certain assumptions are necessary to estimate potential exposures to workers within the digester. This section lists these assumptions that were used in estimating potential worker exposures inside the digester.
The thickness of the scum (sludge) layer attached to the inner surface of the digester is 10 cm. This layer was assumed to be homogeneously distributed all over the inner surface of the digester.
The digester was assumed to have a cylindrical shape with a total volume of 821.2 m3 (29,000 ft ) and a height of 7.16 m (23.5 ft).
I 3
These dimensions were taken from the total bulk volume of all sludge layers and from the sum of thicknesses of all layers.
Tpe total inner surface area of the digester was calculated at 270
[
Thus, considering 0.1 m thickness of scum layer, the total i
m.
volume of contaminated sludge that a decontamination worker will be i
3 exposed to is on the order of 27 m, which is equivalgnt to 27 metric tons of sludge (assuming a density of 1.0 g/cm ).
l A particle size (AMAD) of ly was assumed for the radioactive particulatesthatmaybeattachedtotheresuspendeddrop]etsand i
available for inhalation while cleanup is being performed.
3 A mass loading factor (MLF) of 100 mg/m in the worker breathing zone was conservatively assumed. This MLF represents 0.03-0.13% of l
the inventory of the sludge layer attached on the digester surface.
j 3
Particles of resuspended scum (sludge) may be attached to resuspended f
droplets. These particles and the droplets are not likely to be of an optimum 1
size to maximize. inhalation doses. However, the RESRAD code assumes, for-inhalation dose calculations, such an optimum particle size (an AMAD of 1p).
Thus, subsequently calculated inhalation doses represent conservative upper bound estimates.
11 I
r The breathing (inha]/hr, which is appropriate for scenarios ation) rate of worker in the digester was assumed to be 1.2 m involving physical exertion.
The sludge is completely saturated, except for the outer 1 cm of the sludge.
The radon (zz Rn and z 2Rn) emanation coefficient is 0.4.
The sludge layer on the inner surface of the digester was assumed to contain radionuclides at the same concentration as the average bulk sludge before mixing with municipal waste as given in Table 3 (column 2).
All radionuclides present in the sludge were assumed to be in secular equilibrium with short half-life decay products.
3 The air exchange rate is 2400 m /hr so that the entire volume of the digester is exchanged once every 20 minutes.
Duetoairexchangerateconditionsinsi{gthedigesterand considering the decay rates of zzzRn and Rn and their decay products, specifically with slow decay rate, will not have sufficient time to decay inside the digester; rather, they will be generated outside the digester since the parent radionuclides will be carried away with the outflowing air. Since adequate simulations of such air flow inside the digester is not possible at this stage due to lack of information on details of the cleanup operation, it will be conservatively assumed that worker's dose rates associated with radon and thoron inhalation will be reduced by a factor of 3 as a result of using ventilation during the cleanup operation.
These assumptions are generally conservative because the sludge within the digester will be wet, which reduces radon emanation further. The ventilation will prevent achievement of secular equilibrium between radon and its decay products.
In addition, the amount of material left in the tank may be much less than assumed depending on the removal techniques to be applied. No assumption was made regarding worker occupancy in the dose calculation because the dose will be calculated on hourly basis.
4.3.3 Dose Calculations All deses calculated in this assessment are effective dose equivalents (EDE),
including 50-year committed doses for inhaled radionuclides, and are based on the methodology presented in the International Commission on Radiological Protection (ICRP) reports numbered 26, 30, and 48. The dose rate (mrem /hr) is the unit of calculation in this assessment; the total dose may be obtained by multiplying the dose rate by the appropriate exposure time in hours.
12
q
'k
- Direct Gamma Exposure The direct gamma dose rate was-calculated using the RESRAD computer code z
(Version 4.33). A contaminated source area of 270 m was assumed, which represented the total surface area of the walls of the digester. The.
l thickness of contaminated area was conservatively assumed to be 10 cm.
The average concentrations for all radionuclides listed in Table 3 (column 2) were used and all radionuclides were assumed in secular equilibrium with decay products. All potential exposure pathways listed _
i in the code were suppressed except for the external gamma pathway.'The i
gi, rect dose was calculated to be 2.5 mrem /y. This dose represents all i
Th daughter products in secular equilibrium. Since the default occupancy factor of 0.45 was assumed in the direct gamma dose assessment calculation, the corresponding hourly dose for direct gamma exposure would be-1 2.5 mrem /y / (365 d/y x 24 hr/d x 0.45) = 0.00063 mrem /hr s
Assuming that the decontamination operation'will require an estimated 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> for completion, the maximum projected dose to an individual worker frorgdirect gamma exposure would be ap32out 0.025 mrem. More than 90% of l
this -direct gamma dose resulted from Th and its decay products.
About 75% of this dose would be caused by the contaminants in the sludge f
with the rest attributable to the background concentration of 232 Th (about I pCi/g). Since the RESRAD code assumes a plane geometry for the-i direct gamma radiation exposure and due to the fact that the worker will be exposed to direct radiation in a cylindrical geometry (2r), the dose may be anticipated to be somewhat higher than the estimated value.
)
Inhalation Exposure jq There are two potential pathways that could result in an inhalation dose. The first pathway includes resuspension of radionuclides present in the sludge along with their dgay products. The second pathway involves inhalation of Rn and Rn.and their decay products that may 1
-build up in the atmosphere of the sludge digester.
j i
Resuspension Pathway Dose Assessment The dose rate from inhalation of each radionuclide in the sludge was calculated. NRC staff estimated the inhalation-dose rate for each 3
radionuclide assuming the mass loading factor of 100 mg/m, a breathing l
3 rate of 1.2 m /gr, and the corresponding inhalation dose conversion:
+
factors (DCF%) for each radionuclide present in the sludge.. The radionuclide-specific doses were-then summed to estimate the total' inhalation dose due to resuspension of radioactive particulates.- This.
-l may be represented in the following formula, t
?
I The DCF's listed in RESRAD Version 4.33 code were used'in this calculation.
1 13 I
-I
E D,,, - MLF x BR x E C, x I-(DCF,3),
i t
where 3
the MLF is the mass loading factor f100 mg/m )',
the BR is the breathing rate (1.2 m /hr),
the C, is the concentration of radionuclide f in the sludge, and radionuclide, is the inhalation dose conversion factor for the (DCFinn) f.
The effective dose equivalent conversion factors for inhalation of resuspended radionuclides are given in the following Table:
i i
i r
l l
e a
t f
f i
k t
i
_j e
14 I
~ r i
t i
Radionuclide Inhalation DCF Dose (mrem /hr)
Class (mrem /pC1) 23'U D
2.70E-3 0.14 D
2.50E-3 0.002 23su+D D
2.40E-3 0.003 238Pu W
5.10E-1 0.02 23'Pu W
5.10E-1 0.37 24 Pu W
5.10E-1 0.37 zuAm W
5.20E-1 0.15 232Th W
l.60E O 0.75 226Ra + D W
7.90E-3 0.0003 Total 1.82 Using above equation and the dose conversion factors listed above, the f
inhalation dose rate for each radionuclide was derived and listed above in column 4.
The total inhalation dose due to suspension of airborne particulates from all radionuclides was estimated to be about 1.82 mrem /hr.
Consequently, if the worker spends 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> in the l
digester, the dose from inhalation of airborne particulates would not be expected to exceed about 73 mrem.
222 22 Rn and Rn Inhalation Dose Assessment The outer 1 cm layer of the scum may be dry enough to allow emanation of 22 a
222Rn and Rn from the sludge that is assumed to be attached to the 2
inner wall of the digester. Thus, assuming a surfape area of 270 m, a thickness of 0.01 m, and sludge density of 1.0 g/cm, the dry sludge volume boung to the inner sur,f, ace of the digester was est,1, mated to be 6
2 about 2.7 m.
Assuming that Ra is in guilibrium with Rn, and considering an average concentration of Ra of 0.28 pCi/g, and an 222 emanation coefficient of 0.4, the total Rn inventory inside the digester in a closed digester system (without air exchange) would be:
3 6
3 3
0.28 pCi/g x 2.7 m x 10 g/m x 0.4 - 3.0 x 10 pCi.
The volume of air in the digester was calcu])ated from the original i
volume of sludge in the digester (29,000 ft minus the volume of sludge stuck at the inner surface of the diggster. The volume of air in the digester was p,alculated at 7.942 x 10 liter.
Considering the total i
2 inventory of Rnwillbethoroughlymixedintheairinsidethe 2
digester, the concentration of Rn in the atmosphere that a worker j
15 l
j
.l inside the digester may breath would be about 0.38 pCi/1.
Because some sort of ventilation will be required in accordance with OSHA requirementsforclosedspacg,entryandforhygienicreasons,NRCstaff conservatively assumed that Rn concentration inside the digester 222 atmosphere would be reduced further by a factor of 3.
Thus, the Rn concentration was estimated to be about 0.13 pCi/1.
Based on a dose i
conversion factor of 0.44 rem /y/pC1/1 based on ICRP Publication No. 50
(
(and assuming complete equilibrium with decay products), the total radon hourly dose would be:
(0.44 remly/pCUI x 1000 mrem / rem x 0.13 pCi/D!(365 d/y x 24 h/d) = 0.0065 mremtr Assuming that the worker will spend 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> to complete the work activity in the old digester, the total dose estimated from radon inhalation would be about 0.26 mrem.
Tp2eNRCstaffusedthesameapprg2ach to estimate the dose for thoron
(
Rn). The total inventory of Rn was calculated from the total volume of sludge bound atyhe inner surface of the digester and from the avgrageconcentrationof Th. This inventory was calculated at 4.2 x 10 pCi. Assumin a closed system, g2 complete mixing with the air inside the digester and Rn concentration in air would be 5.3 pCi/1. In a similar manner as was discussed above, a reduction factor of 3 was conservativelyassumgdduetoairexchangefromventilation. Thus, the staff estimated the Rnconcentrationintheolddigesteratmosggere to be about 1.8 pCi/1.
According to ICRP Publication No. 30, a Rn concentration in air of 9 pCi/1 in 100% with all of its decay products maintained over an exposure duration of 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> would impart an inhalgtion dose of 5000 mrem. Therefore, the maximum hourly dose rate from Rn inhalation would be:
[(1.8 pCi/l / 9 pCi/1) x 5000 mrem] / 2000 hr - 0.5 mrrm/hr 22Qe total dose that a decontamination worker may receive from thoron T
Rn inhalation while working inside the digester (assuming 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> to complete the decontamination activity) is estimated to be about 20 mrem.
The overall dose that an unprotected worker may receive due to radon and thoron inhalation during the removal of contaminated sludge attached to the walls of the old digester would, therefore, be about 20.3 mrem.
Total Worker Dose The total hourly dose that a worker would be expected to receive from all potential pathways, namely direct gamma radiation, inhalation of 1
.resuspended radionuclides, and inhalation of radon and thoron, would be as summarized in the following table:
E f
16 I
i i
L l
.=
i Pathway Dose (mrem /hr)
Direct Gamma Radiation 0.0006 r
Inhalation of Radon (222Rn) 0.007 i
Inhalation of Thoron (22eRn) 0.50 l
Inhalation of Resuspended Radionuclides 1.87
(
All Potential Pathways 2.38 i
Based on the above assessment, and assuming the worker would work within the digester for about 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br />, the total dose to that worker without any protective measures would not be expected to exceed about 95 mrem. It should be emphasizul, I
however, that these dose estimates were calculated assuming that worker will not use l
any respiratory protection. In actuality, it is anticipated that workers will use some sort of respiratory protective devices in such a working emironment. Assuming that workers will use air-purifying respirators (e.g., half-mask or full-mask respirators with paniculate filtration), the inhalation dose due to resuspension could be reduced further by a factor of 10 to 50. NRC staff anticipates that workers in the digester would use supplied air respirators because of hygienic and closed space conditions to i
avoid tential non-radiological hazards associated with the work activity (e.g.,
methane accumulation). Using the minimum protection factors for supplied air respirators in Appendix A of 10 CFR Part 20, the inhalation dose would be.
substantially reduced. Therefore, estimated worker doses over 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> are not expected to exceed 8 mrem. These doses are far less than NRC's public dose limit of i
100 mrem /y in 10 CFR 20.1301. Reasonable efforts, such as ventilation of the digester and respiratory protection, should be made to ensure that the doses are as low as is reasonably achievable.
- 5. CONCLUSIONS i
Assuming that the contaminated sludge is disposed in a manner that mixes the sludge with the municipal waste over a period of months, disposal of the sludge from the old digester at either of the landfill sites (Johnson City or Carter County landfills) would not pose i
unacceptable risks to members of the public, who might be exposed to the contamination at some time in the future. Actual doses would be expected to be considerably less than j
estimated in this assessment. Doses to workers who will be involved in removal of the contaminated sludge from the digester and its disposal at the landfill should also be acceptably low, well below NRC's public dose limit in 10 CFR Part 20. Reasonable i
measures to protect the workers against non-radiological h-'ards will also help to reduce l
potential doses to the workers during the removal and dis.,4 sal operation.
i 17 i
r i
I t
s This assessment was a conservative analysis, and probably overestimated the doses that might actually occur at each of the landfill sites.,One of the most conservative assumptions made in this analysis was the location of the intruder well. In actuality, an intruder would probably build along the boundary of the site. There are and will continue to be institutional controls placed on the landfill sites, which should be somewhat effective in preventing the public from having access to the site over the next several decades. If, however, these controls fail, an individual drilling a well inte a municipal waste landfill would most likely realize that this was a burial site and discontinue drilling. The concentrations of uranium in groundwater at a well off-site would be further decreased due to dispersion and retardation that would occur between the cell and the well. Therefore, potential doses to people off-site would be expected to be much less than those calculated here. In addition, anyone digging into the waste would probably recognize that the site was previously used for municipal waste disposal and move away from the site. This would likely limit the extent of direct gamma exposure and dust inhalation that may contribute doses to onsite residents within the first several hundred years.
The analysis also did not consider the protective effects of any liners or other engineered barriers that have been or will be incorporated in the landfill cell. Although these barriers cannot be assumed to remain intact indefinitely, there will realistically be some retardation of the migration rate of the uranium by the liners and other barriers. Even in the event of a failure by the barriers, the cover should remain somewhat effective in reducing the amount of precipitation passing through the waste, and will thereby reduce the mobilization of the uranium. The baniers will also inhibit the release of the radionuclides into the ground, to some extent, even if they are not completely intact. Since no credit was given for either type of barrier in the analysis, the estimated doses are also likely overestimated. In addition, the municipal waste itself may be somewhat effective in retarding the migration of radionuclides, particularly SU, into groundwater beneath the landfill cell.
Taking into account all of the conservative assumptions incorporated in this assessment, the dose to the general public in this area would most likely be much lower than the doses in this analysis. Therefore, disposal of the contaminated sludge from the old digester at the Erwin POTW will not pose a significant risk to the public or to workers performing the cleanup.
- 6. REFERENCES
- 1. Oak Ridge Associated Universities, (T.J. Vitkus),1991, Radiological Characterization of Digester Sludge at the Erwin POTW, Erwin, Tennessee, Report No. ORAU 91/H-22.
- 2. Terinessee Department of Health and Environment,1992, Landfill Information transmitted by Facsimile on October 16,1992, from Randy Curtis to Debra Shults, and Debra Shults to Michael Weber.
/
- 3. U.S. NRC,1991, Radiation Dose and Groundwater Quality Assessment of Waste Water 18 l
i Treatment Plant Sludge Disposal, Erwin, Tennessee, Division of lxw leve1 Waste Management and Decommissioning.
I
- 4. Oak Ridge Associated Universities, (T.J. Vitkus),1991, Supplemental Radiological Characterization ofDigester Sludge at the Erwin PO7W, Erwin, Tennessee, August 13, 1991.
l i
t t
A W
I s
Y h
0 19 i
i
l
-.f TABLE 1 IMPORTANT SITE-SPECIFIC PARAMETERS USED IN RESRAD MODEL FOR JOHNSON CITY REGIONAL LANDFILL PARAMETER VALUE AND UNIT Length Parallel to Aquifer 30.50 m Cover Depth
-Om 3
Density of Contaminated Zone 0.60 g/cm -
Cont. Zone poros!ty.
0.40 Cont. Zone Effective Porosity 0.20 Cont. Zone Hydraulic Conductivity 3.0 m/yr Precipitation Rate 1.0 m/yr Irrigation Rate 0.2 m/yr-Runoff Coefficient Watershed Area
- 0.20 2
1.0 km Unsat/Uncont. Zone Hydraulic Conductivity 3.0 m/yr 3
Density of Saturated Zone 1.6 g/cm Sat. Zone Total Porosity 0.40 Sat.-Zone Effective Porosity 0.20 Sat. Zone Hydraulic Conductivity 1000 m/yr Sat. Zone Hydraulic Gradient 0.02 Drinking Water Intake 7301/yr Drinking Water Fraction 1
Livestock Water Fraction 1
Irrigation Fraction From a Well I-Water Table Drop Rate 0 m/yr.
20
B
.i
.4 l
I;.
j
-i TABLE 2 IMPORTANT SITE-SPECIFIC PARAMETERS USED IN RESRAD MODEL l
FOR CARTER COUNTY /ELIZABETNTON LANDFILL
'l 1
PARAMETER VALUE AND UNIT j
Length Parallel to. Aquifer 30.50 m Cover Depth l~m 3
Density of Contaminated Zone 0.59 g/cm.
i Cont. Zone Total Porosity 0.40 Cont. Zone Effective Porosity 0.20 Cont. Zone Hydraulic Conductivity 0.3 m/yr Precipitation Rate 1.0 m/yr l
Irrigation Rate 0.2 m/yr Runoff Coefficient 0.20 i
2 Watershed Area 1.0 km Unsat/Uncont. Zone Hydraulic Conductivity 0.3 m/yr 3
Density of Saturated Zone
-1.6 g/cm Sat. Zone Total. porosity 0.40 f
Sat. Zone Effective Porosity 0.20 l
Sat. Zone Hydraulic Conductivity 315 m/yr Sat. Zone Hydraulic Gradient 0.049 Drinking Water Intake 730 1/yr Drinking Water Fraction.
1 Livestock Water Fraction 1
Irrigation Fraction from a Well 1
Water Table Drop Rate
-0 m/yr 21
i I
~
TABLE 3 5
WEIGHTED AVERAGE RADIONUCLIDE CONCENTRATIONS FOR ALL SLUDGE LAYERS t
Radionuclide Average Concentration Average Concentration in Sludge (pCi/g) after Mixing with Solid Waste (pCi/g) 23'O 430.6 2.36 2350 7.96 0.04 2380 10.5 0.06 23ePu 0.39 0.002 23U2 Pu 6.12 0.03 241Am 2.41 0.01 232Th*
3.9 0.02 zz6Ra 0.28 0.001 l
232
- Although calculation considered an initial concentration of Th, the buildup occurs quickly enough to achieve equilibrium with progeny.
I 5All concentrations are given in pCi/g.
22
TABLE 4 RADIONUCLIDE CONCENTRATIONS OF SAMPLES No. 12271, 12272, 12273 AND THE MEAN AVERAGE CONCENTRATIONS OF THE SCUM LAYER NUCLIDE S1-12271 52-12272 S3-12273 MEANS1.52.S3I
"'U 741 403 395 513 235U 18.1 7.1 7.6 10.9 238U 8.2 4.9 4.1 5.7 238Pu 0.5 0.47 0.08 0.35.
23'Pu 3.86 2.71 1.25 2.61 2Am 1.53 1.33 0.44 1.1 szTh 0.90 1.80 0.20 0.97 RADIONUCLIDE CONCENTRATIONS AFTER DISPOSAL IN THE LANDFILL 7
RADIONUCLIDE CONCENTRATION foci /a) AFTER DISPOSAL 2"U 1.25 U5U 0.03 238U 0.01 23ePu D.0008 239/241 Pu 0.006 261Am 0.003 n2 Th 0.002 226Ra 0.0006 h
6These values represent radionuclide concentrations in the source-term scenario No. 2, i.e. without dilution.
7These values represent radionuclides concentrations in the landfill after dilution with municipal waste i.e. source-term scenario No. 2 23
f
.?
-\\
l I
t TABLE 5 i
SUMMARY
OF DOSE RESULTS FOR JOHNSON CITY LANDFILL SOURCE-TERM SCENARIO 1
)
i Ictal Dese Contriktiets T005E(i.p.t) for Individual Radionuclides (i) and Pathars (p)
?!
Asstes/yrandfractionofictalDeseAtt= 463.0 years i
1 Water Iridependent Fathays i
Ground Dust Radon Plant Meat Milk Soil
. Radio-l Nuclide stes/yr fract. stes/yr fract, stes/yr fract. stes/yr fract. stes/yr fract. stes/yr fract. - stes/yr fract.
As-241 2.462E-06 0.0000 4.071E-05 0.0000 1.811E-02 0.0161 1.083E-05 0.0000 3.097E-06 0.0000 1.829E-09 f Pu-238 4.650E-08 0.0000 1.827E-05 0.0000 1.167E-10 0.0000 4.651E-06 0,0000 1.329E-06 0.0000 4.673E-10 0.0000 3.314E-06 0.0 l
Pu-239 1.371E-05 0.0000 1.212E-02 0.0107 0.000E+00 0.0000 3.141E-03 0.0028 8.980E-04 0.0008 5.318E-09 0.00!
Pu-240 2.496E-05 0.0000 1.170E-02 0.0104 3.329E-15 0.0000 3.031E-03 0.0027 8.667E-04 0.0008 9.224E-Ra-226 2.660E-03 0.0025 8.466E-06 0.0000 5.222E-04 0.0005 1.576E-02 0.0140 7.687E-04 0.0007 9.758E-1h-232 2.176E-01 0.1929 3.046E-02 0.0270 2.365E-03 0.0021 3.077E-02 0.0273 7.039E-03 0.0062 ' i U-234 3.245E-03 0.0029 4.441E-02 0.0394 5.219E-04 0.0005 3.948E-02 0.0350 7.215E-03 0.0064 9.069E-04 !
U-235 3.6BIE-03 0.0033 1.143E-03 0.0010 0.000E+00 0.0000 8.575E-04 0.0000 2.147E-04 0.0002 1.607E-05 0)
U-238 6.723E-04 0.0006 9.784E-04 0.0009 4.654E-09 0.0000 5.966E-04 0.0005 1.494E-04 0.0001 2.117E-05 0.000{
lotal 2.281E-01 0.2022 1.009E-01 0.0894 2.152E-02 0.0191 9.364E-02 0.0830 1.716E-02 0.0152 9.950!
2 WaterDependentFathays Water fish Radon Platt Meat Milk AllFatha'ys:
l Radio-
)
Nuc!!de stes/yr fract, stes/yr fract. stes/yr fract. stes/yr fract. stes/yr fract. stes/yr1fract. stes/yr fract.
I As-241 ; 4.770E-03 0.0042 7.559E-03 0.0067 0.000E400 0.0000 2.629E-04 0.0002 3.573E-04 0.0003 3.914E-07 0.0000 3!
Pu-238 1.536E-07 0.0000 1.524E-CB 0.0000 0.000E+00 0.0000 1.042E-08 0.0000 1.166E-08 0.0000 3.041E-09 0.000l Pu-239 3.815E-09 0.0000 7.143E-10 0.0000 0.000E+00 0.0000 2.587E-10 0.0000 2.894E-10 0.00
_ Pu-240 8.871E-07 0.0000 8.501E-08 0.0000 0.000!+00 0.0000 6.015E-08 0.0000 6.730E-08 0.000 Ra-226 0.000E*00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.000!
Th-232 0.000E+00 0.0000 0.000Et00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.00 U-234 4.843E-01 0.4293 4.805E-02 0.0426 0.000Ef00 0.0000.3.284E-02 0.0291 3.674E-02 0.0326 9.586El
- U-235 1.332E-02 0.0118 3.336E-03 0.0030 0.000E+00 0.0000 9.035E-04 0.0008 1.011E-03 0.0009 1.712E-04 0.0002' 2.472El U-238 1.141E-02 0.0101 1.132E-03 0.0010 0.000E+00 0.0000 7.737E-04 0.0007 8.656E-04 0.0006 '2.?
.lotal 5.138E-01 0.4555 6.008E-02 0.0533 0.000E400 0.0000 3.478E-02 0.0308 3.89BE-02 0.0345 -9.
24 l
[
i 1
l i
e TABLE 6 r
SUMMARY
OF DOSE RESULTS FOR JOHNSON CITY LANDFILL SOURCE-TERM -
SCENARIO 2
\\
Tctal Ocse Octtrihtict.s TOOSE!i.;,t) for 1ctivic.;al Radictuclides (1) and Path.ays (p) i As stes/yr arid Fraction of Tctal Dese At t 464.3 years
~
i Water Dependent Fathnays
[
Water Fish Radon Plant Meat Milk AllPathays Radic-O clide stes/yf fract. sies/yr fract. stes/yr fract. stes/yr fract. ares /yr fract. stes/yr fract, stes/yr fract.
't As-241 9.54BE-040.0021 1.513E-03 0.0034 0.000E+00 0.0000 5.262E-05 0.0001 7.152E-05 0.00 Pu-238 6.095E-08 0.0000 6.047E-09 0.0000 0.000E+00 0.0000 4.133E-09 0.0000 4.624E-09 0.000i Pu-239 7.232E-10 0.0000 1.353E-10 0.0000 0.000E+00 0.0000 4.904E-11 0.0000 5.aB6E-11 0.00 Pu-240 1.681E-07 0.0000 1.66EE-0B 0.0000 0.000E+00 0.0000 1.140E-0S 0.0000 1.275E-06 0.0000 3.327E-09' O.000I Ra-226 0.000E+00 0.0000 0.000Et00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.000 Th-232 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.I U-234 2.559E-01 0.5731 2.539E-02 0.0569 0.000E+00 0.0000 1.735E-02 0.0369 1.941E-02 0.0435 5!
U-235 8.088E-03 0.0181 2.022E-03 0.0045 0.000E+00 0.0000 5.485E-04 0.0012 6.136E-04 0.0014 1
- U-238 2.741E-030.0*61 2.720E-04 0.0006.0.000E+00 0.0000 1.859E-04 0.0004 2.080E-04 0.0005 !
Total 2.677E-01 0.5995 2.920E-02 0.0654 0.000E+00 0.0000 1.814E-02 0.0406 2.031E-02 0.045 Water Independent Pat hays Ground Duct Radca Platt Meat Milk Scil Radio-Nuclide stes/yr' fract. stes/yr fract. ares /yr-fract, stes/yr fract. stes/yr--fract. stes/rr-fract. stes/yr fract.
!'i 6-241 4.927E-07 0.0000 0.149E-06 0.0000 3.675E-03 0.0082 2.168E-06 0.0000 6.19BE-07 0.0000 3.661E-10 0.0000 L550E-06 0.0000
{
Pu-238 1.634E-08 0.0000 7.206E-06 0.0000 4.670E-11 0.0000 1.834E-06 0.0000 5.239E-07 0.0000 1.255E-10 0.0000 1.307E-06 0.0000 Pu-239 2.603E-06 0.0000 2.301E-03 0.0052 0.000E+00 0.0000 5.963E-04 0.0013 1.705E-04 0.0004 1.010E-09 0.0000.4.263E-04 0.0010
! u 240 4.73BE-06 0.0000 2.220E-03 0.0050 6.349E-16 0.0000 5.755E-04 0.0013 1.645E-04 0.0004 1.752E-09 0.0000. 4.
P Ra-226 1.042E-03 0.0023 3.0B4E-06 0.0000 1.902E-04 0.0004 5.740E-03 0.0129 2.800E-04 0.0006 3.554E-06 0.0000 1.639E-05 0.0000
- i
~Th-232 2.412E-02 0.0540 3.377E-03 0.0076 2.622E-04 0.0006 3.411E-03 0.0076 7.604E-04 0.0017 4.552E-06 0.0000 1.832E-04 0.0004 ~
l
~U-234 1.727E-03 0.0039 2.347E-02 0.0526 2.760E-04 0.0006 2.092E-02 0.0469 3.816E-03 0.0025 4.792E-04 0.0011 1.050E-03 0.0024
-U-235 2.234E-03 0.0050 6.944E-04 0.0016 0.000E+00 0.0000 5.210E-04 0.0012 1.304E-04 0.0003 9.749E-06 0.0000 3.912E-05 0.0001-
,0-238 1.615E-040.0004 2.351E-04 0.0005 1.130E-09 0.0000 1.433E-04 0.0003. 3.58BE-05 0.0001 5.086E-06 0.0000 1.076E-05 0.0000 i
Tota 2.929E-02 0.0656 3.231E-02 0.0724 4.406E-03 0.0099 3.191E-02 0.0715 5.379E-03 0.0120 5.022E-04 0.0011 2.142E-03 0.0048 i
s 25 i
e I
=
TABLE 7 '
SUMMARY
OF DOSE RESULTS FOR CARTER COUNTY /ELIZABETHTON, TN, LANDFILL SOURCE-TERM SCENARIOS 1-a AND 1-b.
ic;al Dose contributions 1005E(1,p,tj for Indivicea! Ra:1cnaclides (i) and Fath.ays (p)
As stes/yr and Traction of Total Dose At t = 3695 years Water Independent Fathways Grond Dust Radon Plant Meat Milk Soil Radio -
.Nuclice stes/yr fract, stes/yr fract. stes/yr fract. stes/yr fract. stes/yr frac 1, stes/yr fract. stes/yr fract.
6 -241 3.32tE-11 0.0000 5.721E-11 0.0000 1.367E-08 0.0000 2.075E-11 0.0000 3.638E-12 0.0000 2.149E-15 0.0000 2.740E-12 0.0000 Pu-239 5.177E-05 0.0000 4.575E-02 0.0051 2.432E-09 0.0000 4.171E-03 0.0005 9.859E-04 0.0001 5.245E-09 0.0000 8.593E-03 0.0009 Pu-240 7.353E-05 0.0000 3.446E-02 0.003B 1.316E-13 0.0000 3.141E-03 0.0003 6.672E-04 0.0001 6.971E-09 0.0000 6.471E-03 0.0007 Ra-226. 9.850E-CB 0.0000 3.726E-10 0.0000 1.899E-09 0.0000 2.385E-07 0.0000 B.16BE-09 0.0000. 1.03BE-10 0.0000 2.253E-09 0.0000 Th-232 1.054E+00 0.1165 1.600E-01 0.0199 1.033E-02 0.0011 6.252E-02 0.0069 1.009E-02 0.0011 5.925E-05 0.0000 9.BB6E-03 0.0011-
'U-234 1.996E-02 0.0022 6.717E-03 0.0007 3.642E-04 0.0000 4.497E-02 0.0050 1.802E-03 0.0002 1.90BE-05 0.0000 6.590E-04 0.0001 U-235 1.223E-08 0.0000 1.135E-08 0.0000 0.000Et00 0.0000 3.623E-09 0.0000 6.414E-10 0.0000 1.164E-!! 0.0000 B.011E-10 0.0000
,U-238 3.171E-07 0.0000 1.089E-07 0.0000 6.067E-09 0.0000 7.107E-07 0.0000 - 2.856E-08 0.0000 3.165E-10 0.0000 1.054E-08 0.0000 To;al 1.074E+00 0.1167 2.670E-01 0.0295 1.071E-02 0.0012 1.146E-01 0.0127 1.344E-02 0.0015 7.635E-05 0.0000 2.561E-02 0.0026 Total Dese Ocntributions T005Eli,p.t) for Incividual Radionuclides (i) and Fathways (p)
As ares /yr and fraction of Total Ocse At t = 3695 years-Water Dependent Pathnays Water fish Radon Plant Meat Milk
~ AllPathmayst-Radio-
' Nuclidel stes/yr fract, stes/yr fract, stes/yr fract. stes/yr fract, stes/yr fract', stes/yr.fract. stes/yr' fract.
As-241 4.947E-06 0.0000 1.702E-06 0.0000 0.000E+00 0.0000 4.B01E-07 0.0000 3.770E-07 0.0000 9.636E-08 0.0000 5.933E-06 0.0000-Pr 239 7.361E-07 0.0000 4.B51E-09 0.0000 0.000E+00 0.0000 7.164E-08 0.0000 5.625E-CB 0.0000 5.46BE-09 0.0000 5.945E-02 0.0066
.Pu-240 7.15EE-05 0.0000 2.463E-07 0.0000 0.000E+00 0.0000 6.946E-06 0.0000 5.455E-06 0.0000 1.423E-06 0.0000 4.489E-02 0.0050
-Ra-226 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 3.49BE-07 0.0000 Th-232. 0.000E*00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 ' O.000E+00 0.0000 0.000E+00 0.0000 1.327E+00 0.1466 -
' U-234 5.72BE+00 0.6330 1.971E-02 0.0022 0.000E+00 0.0000 -5.560E-01 0.0614 4.366E-01 0.0482 1.139E-01 0.0126 6.929E+00 0.7657 0.000E+00 0.0000 4.297E-02 0.0047 3.374E-02 0.0037 2.073E-03 0.0002' 5.247E-01 0.05B0 U-235 4.427E-01 0.0469 3.213E-03 0.0004 U-238 1.373E-01 0.0152 4.726E-04 0.0001 0.000E+00 0.0000 1.333E-02 0.0015 1.047E-02 0.0012 2.731E-03 0.0003 1.643E-01 0.0182 -
,' Tctal '6.30BE+00 0.6971 2.340E-02 0.0026 0.000E+00 0.0000 6.123E-01 0.0677 4.80BE-01 0.0531 1.187E-01 0.0131 9.049E+00 1.0000
-sSusofallmaterindependentanddependentpathwers.
26
TABLE 8
SUMMARY
OF DOSE RESULTS FOR CARTER COUNTY /ELIZABETHTON, TN, LANDFILL SOURCE-TERM SCENARIO 2 Ictal Ocse (catri0utions TD05Eli p.t) for Individual Kadionu:lices (1) and Fathnays (p)
As stes/yr and fraction cf Tctal Dese At t 2 3696 years Water Independent Pathnays Ground Dust Radca Plant Meat Milk Scil f
R m c-Oc!!st
- /yr fra:t. zies/yr fra:t. stes/yr fract. stes/yr fract. stes/yr fra:t. stes/yr fract. stes/yr fract.
Aa-241 1.d3E-X 0.0% 2.a7E-110.0X0 3.i23E-Gi 0.000 6.432E-12 0.0000 7.372E-13 0.0X0 4.354E-16 0.000 1.11eE-12 0.0000 Pu-239 1.973E-3 0.0000 1.72tE-02 0.0021 7.629E-10 0.0000 1.565E-03 0.0002 1.677E-04 0.0000 9.925E-10 0.0000 3.276E-03 0.
Pu-240 ~.s%E-05 0.000 1.3XI-02 0.0016 4.23EE-14 0.0000 1.194E-03 0.0001 1.263E-04 0.0000 1.320E-09 0.0000 2.467E-03 0.00 Ra-22t 7.20eE-05 0.000 2.7hE-10 0.00% 9.773E-10 0.0000 1.742E-07 0.0000 2.976E-09 0.0000 3.760E-11 0.0000 1.650E-09 0.00l Th-232 2.344E-01 0.0269 3.967E-02 0.0049 1.941E-03 0.0002 1.355E-02 0.0017 1.117E-03 0.0001 6.559E-06 0.0000 2.201E-03 0 U-234 2.123E-02 0.0026 7.0ESE-03 0.0009 2.676E-04 0.0000 4.776E-02 0.0059 9.546E-04 0.0001 1.011E-05 0.0000 7.01EE-04 0 U-225 1.493E-;B 0.0000 1.372E-06 0.0000 0.000E+00 0.0000 4.411E-09 0.0000 3.694E-10 0.0000 7.06BE-12 0.0000 9.779E-10 0.0 %t U-232 1.535E-07 0.0000 5.226E-OS 0.0000 2.067E-09 0.0000 3.436E-07 0.0000 6.BB7E-09 0.0000 7.629E-11 0.0 M 0 5.109E-09 0.00 Tctal 2.557E-01 0.0315 7.702E-02 0.0095 2.226E-03 0.0003 6.442E-02 0.0079 2.365E-03 0.0003 1.667E-05 0.0000 B.646E-0 Water Oependent Fathways kater fish Raden Plant Meat Milk AllFathways:
Radic-kclice stes/yr fra:t. stes/yr fract. stes/yr fract, stes/yr fract. stes/yr fract. stes/yr fract. sreatyr fra:t.
As-241 2.019E-06 0.0 00 3.464E-09 0.0% 0 0.000E400 0.0000 1.959E-07 0.0000 7.672E-06 0.0000 2.002E-CB 0.0000 2.319E-06 0.0000 Pu-%9 2.819E-U 0.0000 9.242E-10 0.0 % 0 0.000E+00 0.0000 2.736E-CB 0.0%D 1.072E-05 0.0000 1.041E-09 0.0000 2.231E-02 0.0026 Pu-240 2.734E-05 0.0 % D 4.t91E-08 0.0000 0.000E+00 0.0000 2.653E-06 0.0000 1.039E-06 0.0000 2.711E-07 0.0000 1.6EEE-02 0.0021 Ra-226 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 2.522E-07 0.0000 Th-232 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0,000E+00 0.0 3 0 0.0 XEt00 0.0000 0.000E+00 0.0 3 0 2.932E-01 0.0361 U-234 6.109E+% 0.7531 1.048E-02 0.0013 0.000E+00 0.00% 5.92iE-01 0.0731 2.322E-01 0.0256 6.055E-02 0.% 75 7.083Et00 0.6732 U-235 5.4 XE-01 0.0669 1.965E-03 0.0%2 0.000E+00 0.0000 5.271E-02 0.0065 2.064E-02 0.0025 1.26EE-03 0.0%2 6.li6E-01 0.0764 U-236 6.6r4E-02 0.00!E 1.144E-04 0.0000 0.000E+00 0.0000 6.470E-03 0.0009 2.534E-03 0.0003 6.611E-04 0.0001 7.644E-02 0.0094 Total 6.719E+00 0.6263 1.256E-02 0.0015 0.000E+00 0.0000 6.521E-01 0.0504 2.554E-01 0.0315 6.251E-02 0.0077 6.111E+00 1.0000 45cs of 411 hater incepenotat and ce;endent pattnays.
27
TABLE 9
SUMMARY
OF DOSE RESULTS FOR EXPOSURE OF WORKER INVOLVED IN TIIE CLEANUP OF TIIE DIGESTER Tcta! 0:se 0cr.trihticts T005E(i,;,t) for IndiW:Lal Radienu:lides (i) and Pattrays (p)
As stes/yr and Fractict of icta! 0:se At t = 0.000E+00 years GaterIndependentFathays Ercat:
Ocs:
Radcn Flatt Meat Milk Stil hec-tc!!;s stesar tract. stes/yr fract. stes/yr fract. siestyr fract. stes/yr fract. stes/yr fra:t. ares /yr fract.
As-241 2.i74E-02 0.0!!i 0.000E+00 0.0000 0.000Et00 0.0000 0.000E40 0.0000.0.000E+00 0.0000 0.000E 40 0.0000 0.000E 4 0 0.0000 N-236 1.716E-04 0.G0: 0.00*E40 0.0000 0.000E 40 0.0000 0.000Et00 0.0000 0.000E 4 0 0.0000 0.000E 4 0 0.0000 0.000Et00 0.0000 i
N-23i 2.3;;E-;3 0.005 0.000Et00 0.0000 0.000Et00 0.0000 0.000E*00 0.0000 0.000E40 0.0000 0.00;E40 0.0000 0.000E+00 0.0000
'N-240 2.472E-03 0.0%0 0.000it00 0.0000 0.000Et00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000EtX 0.00;; D.00'E 4 0 0.0000 ita-226 5.336E-010.2136 0.000E40 0.0000 0.000E40 0.0000 0.000i+00 0.0000 0.000Et00 0.0000 0.000E 40 0.0000 0.000Et00 0.0000 TM ' !.527E-03 0.0006 0.000E 4 0 0.0000 0.000E 4 0 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 J-234 1.737E-Z 0.0c96 0.000Et00 0.%00 0.000Et00 0.0000 0.000! 40 0.0000 0.000E*00 0.0000 0.000! 40 0.0000 0.000E400.0000 J-235 1.50?E4 0 0.6033 0.000E+00 0.0000 0.000E+00 0.0000 0.000E 40 0.00% 0.0 %E+00 0.0000 0.000E+00 0.0000 0.000E400 0.0000 J-238 2.479E-0; 0.01i3 0.0%Et00 0.0 %0 0.000Et00 0.0% 0 0.000E*00 0.%00 0.000Et00 0.0 M0 0.000E 4 0 0.0000 0.000E+00 0.0000 Tctal 2.437E 40. 0 %; 0.0 E+00 0.0000 0.000E+ % 0.%00 0.000E40 0.0000 0.000E+00 0.0000 0.000E40 0.0000 0.000E40 0.0000 icial Ocss 0catributicas T005E(1,;,t) for Ir. divi: cal Radictu:lides (i) and Fathays (p)
As ares /yr and Fraction of Total Ocse At t = 0.000E40 years Water Depen:ent Fath*ays s;i; iast itacen Fiant ha Min Ali Fa:r..aiu ta;1c-w.c4 arcaor fra;;. sitsisi f;a:t stes/yr fra::. stes/yr fra:t. sissar fra;t. stes/yr tract. c esor fract As-241 0.0 %E4 0 0.0 %0 0.0%E+ % 0.0;;0 0.0%E40 0.0000 0.000E 40 0.0000 0.000E 4 0 0.0000 0.000E+00 0.0% 0 2.974E40 0.03 i N 235 0.000Et % 0.% % 0.0%E400 0.0000 0.000E 4 0 0.0000 0.000E+00 0.0000 0.0 ME 4 0 0.0000 0.000E400 0.0000 1.73E-04 0.0001 N-239 0.0%E40 0.0%; ;.0%i,00 0.0 % 0 0.0%E+00 0.0000 0.0%E+00 0.0000 0.0 %E+00 0.0000 0.000E+00 0.0000 1.3 %E-03 0.0005
+
N-240 0.000!4; 0.0C0 0.CCE40 0.%% 0.0ZEt00 0.00% 0.0 %Et00 0.00% 0.000E+00 0.0000 0.0 ZE+00 0 0 00 2.47'E-03 0.0010 13-H6 0.%0E+00 0.0%0 0.0% EGO 0.00% 0.000E+00 0.0%0 0.0%E+00 0.0000 0.000E40 0.0000 0.000E*00 0.0000 5.33BE410.2%E I N 02 0.0%E40 0.%'0 '.0%!40 0.00% 0.% 0E+00 0.0%0 0.000E+00 0.00% 0.0?0E+00 0.0000 0.000E+00 0.0000 1.5'7E-03 0.0 %6 P.34 0.0 %E+00 0.0 %0 0.0%EtM 0.0000 0.000E40 0.0%0 0.%0E40 0.0%0 0.0%Et00 0.0%; 0.000E+00 0.0000 1.737E-01 ;.Cei6 r235 0.000Et00 0.M Z 0.000E 40 0.0 X 0 0.000E+00 0.0000 0.000E 40 0.0000 0.000E+00 0.0000 0.000E+00 0.0000 1.507E400 0.6033 M 35 0.X;E+ % 0.0 %0 0.00'E4 0 0.0000 0.000E+00 0.0000 0.0%E+00 0.0000 0.000E+00 0.0000 0.000Et00 0.0000 2.47iE-01 0.09i3 icial 0.0%E 40 0.0000 0.000E+00 0.0000 0.000E+00 0.0 %0 0.000E 40 0.0000 0.000E+00 0.0000 0.000E+00 0.0%0 2.497E+001.0000 25cs si all mater indepencent and dependett pattesys.
28
~
i FIGURE I A SCIIENIATIC DIAGRA51 SIIOWING DIFFERENT LAYERS ACCUMULATED IN TIIE OLD DIGESTER i
NORTH MANHOLE
/
I SURFACE SAMPLE BOREHOLE SAMPLER 5 6 LAYERS SCUM LAYER BORE HOLE SAMPLER 7' 6' TURCO SAMPLER 11' 6" I-SLUDGE SLURPER 13' 6" i
i 4
I
-E-SLURRY SLUDGE SLURPER 15' 6' THICK SLUDGE SLUDGE SLURPER 17' 6' 3-TURC0 SAMPLER 19' 6' P
4 SLUDGE + GRIT TURCO SAMPLER 21' 6' 5,
GRIT TURCO SAMPLER 23' 6' i
29 i
1
l%_
,,ili dil!
1 f: ]:d1Ti.))-))T, u.
- iz s
l'f.b i
ll
~
- y i
I I
/
i 2
l,.
-$$ t
!i !
i
.e
<- 2
{ 4! *
- t. e:
s
,f-0 3:
C 1 /
,1.
w
/
?
k j ':.
l m
w d
L:
y...-a-W- -- a ! v,~ - uI M-
,z v~*..
,' / a
.Q g, 4/lS"02 o
' 'BMENmmgh l
H eg Qf M M@
k.._NN$ih.
bf jjN/
l $$gMEF/
B}GP
! (Ghi I
c'4,34 g.. y.)b>
e
.. - Mg: t..
'n
, s v.
hif S
N l
g t1 I:We"S,'T i
ur
,4 3o
)
i
l l
4 FIGURE 3 l
n CARTER COUNTY /ELIZABETIITON TN, LANDFILL SITE LAYOUT SIIOWING SLUDGE DISPOSAL AREAS l
i
?)$7,f l37 - %.%'f %
k N e k.'
~ ' ~ ~
...q.f 3 . 2'. ' Q
. %,. T '~v n.w -
g.
Fl e.'
E l
co c, G (M,
,,/,y.
\\, Ngt..
e q-
'fY, g, o i.* 'jf'f!
' f.
5a
..,, t' } '
l r
y
~
5
[
9h*
\\
ri "s-
~
-.. Q. ' c.i g. yr-. m.~W -
~
~
w i
a Q%
~
8,- E l. T f~
.-s s
- . d :'.~.s..,.;, M. y.i L <... h..... '
lf-lJ3(%
S 3,
l n-sm r
( lnl.
m t,, a~ M. :. %x ' W :g g.. ! 9
,f, [/
~
a SITE l
'~
Y
<u -
Q. \\ s,e.
s s-
))e.
cN. w.
i.
y<< i,5.-_
,.=., >>g - fW.. g./.
.t
..,s*
s
.a i
~
- r.,/
.i.,i.:.,< Q:s:, :;,---. ) +...,
.v
~
i w,;,
/. ll r., '
.?'
i:.+sF,- ?
w
,$ \\\\h'h /f -
. Q ),} (CD ; A.')<~~~~..]6,-.
/*
t l1 y
/
.l s ]
i.f l
f:
^*
'c I:
..('
-~--
1
/
.pl. 1
//
L.
-~.
<W*
l t
~
g.
g!
//
4 Ys. -
3 a.
- .c.....
s h.
g j
ou m
,s,,,,,,,
p
-,~<-~s-
.w,
/
~
-: e
-- 1 !
. *" :4,.. k
~
- i n
sq
. g : K----yyi pun n.p. /
r
,,.s l
Qe.c.,,,c,,,, M i.:. G ;-
\\
'. )
=
. i' J M._,'*f.....
,n m -
+ - -,
.-wr-. -
j
~-.
i~.;.
E.,k if ~~~d. '...., '
4....
...... ~.
r y n,,,-
s t
a
~
.,,. :.,)9 Mf )/./
~
t is <,
. l'n.&~r_t~h.
3*..P ' i lG.. %r,y-~ >
//
p
.s nur E Esot,,,,,r g / /
(,]
N 'fp ', <"",.~~
l
'kE7s&s$5.21TO.,
- ~ -. #.i -^. f. D.... ".*.N
'~
. -~
I n.
v.
...fn.##.,
~
,%. /
+..,
.,. c S CALE.x ",,=,2000' I
n
~.
31 I
g.m.
k
- .g *
- g l
~
FIGURE 4 i
-TOTAL DOSE: ALL ISOTOPES AND PATHWAYS SUMMED FOR JOHNSON CITY,-
E TN,' LANDFILL (SCENARIO 1).
l l,
i TOTAL DOSE: All Isotopes and Pathways Summed.
J
?
1.2
't 1.0 l
.f.:
0.8
~
x N
. t
~C a
f L
0.6 g
g-i 0.4 a
.i
- l 0.2 1
10 100 1000
'10000
~
Years BRJCITY.DAT 03/04/93 14:41 i
- l i
i 32
~
m
_...e, j
'i
~
FIGURE 5 TOTAL DOSE: ALL ISOTOPES AND PATHWAYS SUMMED FOR JOHNSON CITY, I
TN, LANDFILL (SCENARIO 2) l i
i 1
'.$i I
TOTAL DOSE All Isotopes and Pathways Summed O.5 s
s l
t 0.4
{
W L 0.3 l
X
\\
i 4
{
c-g, O
.j 0.2 9
p
- s 0.1
=
0.0
....i
.i 1
10 100' 1000.
10000-I' Years' BRJCITY.DAT 03/10/95.14:09 d
t r
?
^[
3 3.-
.i
'i e
i g.
f FIGURE 6 TOTAL DOSE: ALL ISOTOPES AND PATHWAYS SUMMED FOR CARTER COUNTY /ELIZABETHTON TN, LANDFTLL (SCENARIO 1-a) ~
i i
i i
i t
DOSE: All Isotopes Summed 3
Water Independent & Dependent Subtotals l
12 i
t d
r 10 -
i
.l
~
ll i
j}
j' 8
lI l'
i x
lI I
I-N E:. 6 ll.
il r
r P
ll if 5
~
l Il
~
4_
I il I I
-.11 1\\
id
't 2-G - Independent '
I g I,'
A - Dependent-l
.l h
~
aA J.d e
+
o.
+
i 10 100 1000 10000-l
- Years i
03/11/93 09:15 CARTER.DAT 34 L;
l
(
i FIGURE 7 l
TOTAL DOSE: ALL ISOTOPES AND PATIIWAYS SUMMED FOR CARTER COUNTY /ELIZABETIITON TN, LANDFTLL (SCENARIO 1-b) i e
1 TOTAL DOSE: All isotopes and Pathways Summed 8
l
'i y
b T
7L I
a r
I jf 1
6!
F t
5 [.
J X
N I
4
~
O I
9 bI k
r E3I l-
[
.O 2-i I
~
t 1-_
~
0 th j M
t 1
10 100 1000 10000 Years CARTER.DAT 03/11/93 11:01 1
35 t
j.,,
i I
FIGURE 8 i
?
TOTAL DOSE: ALL ISOTOPES AND PATIIWAYS SUMMED FOR CARTER i-COUNTY /ELIZABETIITON TN, LANDFILL (SCENARIO 2)
{
l i
TOTAL DOSE: All Isotopes and Pathways Summed I
7 j
's i
.l i
r 6 '.
1 U
l
[
r H
5 '_
il i
s I
t i
i h4" i
N 1
1',
5 1
3 F S=
ld L
2 1,f 3
i i -n 1
l r,
4 0c a
/\\ l 1
1 10 100 1000 10000 Years CARTER.DAT 03/11/93 13:05 i
l l
36
,4*~
l FIGURE 9 TOTAL DOSE: ALL ISOTOPES AND DIRECT GAADIA EXPOSURE PATIIWAY FOR OCCUPATIONAL WORKER INVOLVED IN THE CLEANUP OF THE DIGESTER i
TOTAL DOSE: All Isotopes and Pathways Summed 7
1 s
8 i
4 6'
3 r
1 f
/
T 4
5'
\\
r
/
\\
i
/
\\
i f
/
\\
7 x4
/
8 N
r s
C
'l t
k3 0
=
~
2 r l
l t
1 F'
\\
J L
o$
b.
h s
i 10 100 1000 10000 Years DIRECT.DAT 03/11/93 14:52 37 i
l i%
~
l l
l t
PLATE 1: A PANORAMIC VIEW OF TIIE OLD DIGESTER l
l
)
\\
i l
PLATE 2: AN OVERVIEW OF TIIE CRUST DRY SURFACE SIIOWING MUD-LIKE CRACKS
\\
i I
l i
l l
l l
38 1
1