APPENDIX G
AIR MODELING
ACRONYMS AND ABBREVIATIONS
ACRONYMS AND ABBREVIATIONS
| CFR | Code of Federal Regulations |
| DST | double-shell tank |
| EPA | U.S. Environmental Protection Agency |
| HLW | high-level waste |
| ISC2 | Industrial Source Complex Model |
| ISCLT2 | long-term ISC2 |
| ISCST2 | short-term ISC2 |
| LAW | low-activity waste |
| TWRS | Tank Waste Remediation System |
| WAC | Washington Administrative Code |
| WESF | Waste Encapsulation and Storage Facility |
| NAMES AND SYMBOLS FOR UNITS OF MEASURE, RADIOACTIVITY, AND ELECTRICITY/ENERGY | |||||
| Length | Area | Volume | |||
| cm | centimeter | ac | acre | cm3 | cubic centimeter |
| ft | foot | ft2 | square foot | ft3 | cubic foot |
| in | inch | ha | hectare | gal | gallon |
| km | kilometer | km2 | square kilometer | L | liter |
| m | meter | mi2 | square mile | m3 | cubic meter |
| mi | mile | ppb | parts per billion | ||
| ppm | parts per million | ||||
| yd3 | cubic yard | ||||
| Mass | Radioactivity | Electricity/Energy | |||
| g | gram | Ci | curie | A | ampere |
| kg | kilogram | MCi | megacurie (1.0E+06 Ci) | J | joule |
| lb | pound | mCi | millicurie (1.0E-03 Ci) | kV | kilovolt |
| mg | milligram | Ci | microcurie (1.0E-06 Ci) | kW | kilowatt |
| mt | metric ton | nCi | nanocurie (1.0E-09 Ci) | MeV | million electron volts |
| pCi | picocurie (1.0E-12 Ci) | MW | megawatt | ||
| V | volt | ||||
| W | watt | ||||
| Temperature | |||||
| C degrees centigrade | |||||
| F degrees Fahrenheit | |||||
G.1.0 INTRODUCTION
This appendix describes the air dispersion modeling that was performed to assess the impacts on air quality resulting from normal operations associated with the various Tank Waste Remediation System (TWRS) alternatives. The analyses were conducted to accomplish the following objectives:
- Compare the analyzed impacts of potential criteria pollutant releases against National Ambient Air Quality Standards and applicable Washington State regulations;
- Compare the analyzed impacts of emissions of toxic and hazardous air pollutants against applicable Washington State regulations; and
- Compare the analyzed impacts of emissions of radionuclides against applicable Washington State and Federal standards.
The following sections describe the proposed Hanford Site TWRS alternatives and discuss the dispersion models used in the analyses. The remaining sections describe the methodology of the modeling approach, the data used as input to the model (meteorology, source, and receptor parameters), and the results of the modeling effort.
G.2.0 DESCRIPTION OF ALTERNATIVES
The remedial alternatives are broadly separated into those activities related to remediating the tank waste, and those activities involving remediation of the cesium (Cs) and strontium (Sr) capsules. The following alternatives were studied:
- Tanks Waste Alternatives
- No Action - The waste would be maintained in the existing tanks.
- Long-Term Management - The double-shell tank (DST) waste would be transferred to newly constructed DSTs. The tanks would be replaced twice, at 50-year intervals.
- In Situ Fill and Cap - Waste would be disposed of in situ by filling the tanks with gravel and placing a Hanford Barrier over them to inhibit infiltration of rain water or human intrusion.
- In Situ Vitrification - The waste contained in the existing storage tanks would be vitrified in-place.
- Ex Situ Intermediate Separations - The tank waste would be separated into high-level waste (HLW) and low-activity waste (LAW) and the waste vitrified. The LAW would be disposed of onsite in subsurface vaults, and the HLW would be shipped offsite for disposal at the potential geologic repository.
- Ex Situ No Separations - Under the vitrification option, the waste would be immobilized as glass cullet. Under the calcination option, the waste would be treated at temperatures below those required for vitrification, with a resulting dry-powder waste form. All of the treated waste would be shipped offsite for disposal at the potential geologic repository.
- Ex Situ Extensive Separations - This is an extension of the Ex Situ Intermediate Separations alternative. The difference is that waste would undergo a more extensive series of processing steps that would result in a smaller volume of HLW and a larger volume of LAW. Vitrification and disposal activities would be similar to those in the Ex Situ Intermediate Separations alternative.
- Ex Situ/In Situ Combination 1 and 2 - These alternatives are a combination of the Ex Situ Intermediate Separations alternative and the In Situ Fill and Cap alternative. Waste would be retrieved from 70 tanks (Combination 1 ) or 25 tanks (Combination 2) , separated into LAW and HLW, and vitrified. The LAW would be disposed of onsite in LAW vaults, and the HLW would be shipped offsite for disposal at the potential geologic repository. The remainder of the tanks (107 under Combination 1 and 152 under Combination 2) would undergo fill and cap, as described for the In Situ Fill and Cap alternative.
- Phased Implementation - For the first phase of this alternative, two demonstration vitrification facilities would be built and operated. One facility would treat LAW, while the other would separate and treat LAW and HLW streams. For the second phase of this alternative, the facilities from the first phase would continue to operate and large-scale facilities would be built to separate the tank waste into HLW and LAW. The LAW would be disposed of onsite in subsurface vaults, and the HLW would be shipped offsite for disposal at the potential geologic repository.
- Cesium and Strontium Capsules Alternatives
- No Action - The capsules would be maintained in the Waste Encapsulation and Storage Facility (WESF).
- Onsite Disposal - The capsules would be transferred from their existing location to a newly constructed drywell storage facility.
- Overpack and Ship - The capsules would be retrieved from their existing location, transferred to a newly constructed repackaging facility, repackaged, and transferred to a storage location pending future disposal at the potential geologic repository.
- Vitrify with Tank Waste - The capsules would be retrieved, and the contents would be vitrified along with the HLW.
G.2.1 SOURCE IDENTIFICATION AND CHARACTERIZATION
Reviewing available data resulted in identifying several locations and processes expected to emit air pollutants (WHC 1995c, j, n, and Jacobs 1996). The following discussion describes the location and nature of each of these sources. Section G.2.2 details the manner in which these sources were grouped to analyze each alternative. Section G.3.1.2 discusses the emission rates assigned to each source for each alternative.
Pollutant emitting activities were depicted as either area sources or point sources in the dispersion models. Area sources are used for simulating emissions that exist in a known area of activity, especially if the exact source locations are unknown or are expected to move from time to time. In other words, the emissions occurring within the area need not be uniform over space or time. Area sources are defined in the model as square areas and are assigned an areal emission rate (typically specified as grams per square meter per second [g/m2/s]). In this study, the area sources were chosen to include the area in which most of the emissions from a particular operation or grouping of sources would be expected to occur.
Point sources are used for simulating the emissions from sources that are expected to remain in a fixed location and are vented through a stack. The models consider the effects of elevated release heights, building downwash, release temperature, and release velocity when calculating predicted concentrations from point sources. Figure G.2.1.1 shows the source locations used in the modeling scenarios.
Tank Farms
Area sources were used to represent logical groupings of tanks and tank farms. Locations of all sources for all alternatives are shown in Volume Two, Appendix B. Eleven such groupings (identified as TF1E through TF11E) were assigned to tanks in the 200 East Area, while six groupings (TF1W through TF6W) were assigned to the tanks in the 200 West Area. Air emissions that are assumed to occur in these areas include:
- Vehicular emissions associated with construction activities at these sites; and
- Emissions of radiological and nonradiological components from the tanks for all alternatives during continued operations, retrieval, and gravel filling operations.
Waste Retrieval Annex Areas
As part of the ex situ alternatives, the Ex Situ/In Situ Combination 1 and 2 alternatives, and the Phased Implementation alternative, waste transfer annexes would be constructed to collect and distribute the waste retrieved from the tanks. Two such facilities (identified as TA1E and TA2E) are expected to be constructed in the 200 East Area, while three facilities (TA1W, TA2W, and TA3W) would be constructed in the 200 West Area. All annexes would be the same size, except the facility identified as TA2W, which would be larger and also serve as a waste sampling facility.
Although no emissions would be expected to result from operating these facilities, vehicular emissions and fugitive dust would be produced during their construction. These sources were depicted as area sources in the dispersion models.
Concrete Batch Plant
A concrete batch plant would be constructed to support construction activities. For each model scenario, the batch plant was assumed to have sufficient capacity to support the remediation activities. For the purpose of impact assessment, this batch plant was assumed to be located between the 200 Areas. The emissions from this process were modeled as an area source (identified as BTCH).
Figure G.2.1.1 Emission Source Locations
Process Facilities and Tank Farm Construction
Emissions from constructing the processing facilities related to the ex situ and Ex Situ/In Situ Combination 1 and 2 alternatives would include vehicle exhaust emissions and fugitive dust released during earthmoving operations. A single area source (identified as PROC) centered on and equal in size to the disturbed area (80 hectares [ha] [200 acres (ac)]) expected for constructing the process facilities for the Ex Situ Intermediate Separations alternative was used to model these emissions. Bounding case construction emissions related to constructing retrieval equipment at the tank farm locations were modeled as an area source at the tank farm designated TF6W.
For the first phase of the Phased Implementation alternative, two processing facilities would be constructed. Emissions associated with this activity would include vehicle and heavy equipment exhaust emissions and fugitive dust releases. A single area source (FCPI), which encompasses the locations of both plants, was used to model these emissions. In addition, particulate matter emissions from the Pit 30 site (BTCH) would occur.
During the second phase of this alternative, large-scale facilities would be constructed to treat the remainder of the tank waste. Emissions would come from constructing the five waste transfer annexes, process facilities, and a concrete batch plant. Emissions from erecting retrieval equipment at the tank farms would occur simultaneously.
Borrow Site Excavation
For the In Situ Fill and Cap alternative, particulate matter emissions would result from the use of heavy equipment to excavate and transport borrow materials from Pit 30, which is located between the 200 East and 200 West Areas at the same location as the concrete batch plant (BTCH).
For all tank waste alternatives except the No Action alternative, excavation of borrow materials from the Vernita Quarry and McGee Ranch would result in similar particulate matter emissions. These emissions would be associated with installing post-closure barriers over the tank farms. Because of a lack of data concerning these operations, specific emissions estimates and modeling were not performed. However, any such operations would include appropriate control measures (such as using surfactants and water spray procedures) that would result in compliance with Federal and State air quality standards.
Process Facilities Operation
Essentially all the emissions during the processing operations for the ex situ alternatives and the Ex Situ/In Situ Combination 1 and 2 alternatives would occur through the main processing facility stacks. The LAW and HLW processing facilities stacks for the Ex Situ Intermediate Separations alternative were designated as ST-L and ST-H, respectively. The Ex Situ No Separations alternative would have one stack, identified as SMIN. Although two plants would operate in the Ex Situ Extensive Separations alternative scenario, emissions from both plants would be routed through a common stack, designated as ESEP. Processing facilities for the Ex Situ/In Situ Combination 1 and 2 alternatives would be similar to, but with less capacity than, facilities for the Ex Situ Intermediate Separations alternative. Because stack locations and release parameters are expected to be similar, these stacks were modeled using sources ST-L and ST-H. All stacks were modeled as point sources.
Emissions from the vitrification processing facilities that would be constructed for the Phased Implementation alternative would be routed through stacks. The stack for the Phase 1 LAW processing facility was designated as SSPI, while the Phase 1 combined LAW/HLW processing facility stack was designated as NSPI. The stacks for the Phase 2 full-scale LAW processing facilities were designated as ST-L1 and ST-L2. The full-scale processing facility stack was designated as ST-H. All stacks were modeled as point sources.
In Situ Vitrification Process Stacks
During vitrification operations for the In Situ Vitrification alternative, off-gases would be treated and released through one process stack per tank farm. Although two tanks from a single tank farm would be vitrified simultaneously, it was assumed that emissions from both vitrified tanks would be discharged from a single stack. The facility location that would produce the highest impact (in association with the construction emissions) was identified to be at the tank farm location known as TF6W. A point source (identified as IS6W) was used to model emissions from the process stack.
Drywell Storage Facility
A Drywell storage facility would be constructed as part of the Onsite Disposal alternative for the Cs and Sr capsules. The emissions resulting from the construction of this facility are represented as an area source identified as DWSF. No emissions were assumed to result from the operations phase of this alternative.
Capsule Packaging Facility
The capsules Overpack and Ship alternative would involve emissions resulting from constructing and operating a Capsule Packaging Facility (CPF). These emissions are represented by an area source identified as CPF.
Waste Encapsulation and Storage Facility
Routine radiological emissions from the WESF were analyzed for all alternatives. These emissions would occur through a stack, and were modeled as a point source (WESF).
Evaporator
Operating an evaporator during continued operations and waste processing operations is expected to release radiological and nonradiological components. These emissions would occur through a stack, and were modeled as a point source (EVAP).
W-314 Project
This project potentially involves the replacement of various transfer lines located in the 200 East and 200 West Areas. The data available for this project indicate that construction activities would be spread out over various areas and would be of relatively low intensity compared to construction activities associated with other TWRS alternatives. In addition, dust-control measures would be employed that would minimize emissions from these activities. Because substantial emissions are not anticipated, the emissions from the W-314 Project were not separately analyzed.
G.2.2 MODEL SCENARIOS
The various alternatives would involve emissions from one or several of the sources described previously. Implementing alternatives would involve an initial phase of facility construction followed by a phase during which the treatment, transfer, or repackaging processes would occur. Consequently, each alternative could have different phases in which the emissions and analyzed impacts were distinctly different. Therefore, the emissions and analyzed impacts resulting from each phase were calculated and are reported separately for each alternative. The following sections discuss each proposed TWRS alternative and describe the associated emissions sources.
G.2.2.1 Tank Waste Alternatives
No Action Alternative (Tank Waste)
The No Action alternative would involve routine radiological and nonradiological emissions from continued operation of the storage tanks, and continued operation of the evaporator as a waste management activity. In addition, routine radiological releases from WESF would occur and are considered. No construction activities would be associated with this alternative.
The emissions from the continued operations of tank farms would also occur during the construction and operation phases of the alternatives, and are included in the analysis of these alternatives.
Long-Term Management Alternative
The Long-Term Management alternative would involve two phases having air emissions, each of which was analyzed separately. The first phase would involve transferring waste from existing DSTs to newly constructed DSTs 50 years in the future. Waste from the SSTs would not be retanked. The new tanks would be constructed in the same area as the process facility that would be built for the Ex Situ Intermediate Separations, Ex Situ No Separations, and Ex Situ Extensive Separations alternatives; the construction emissions were modeled by assigning them to the location PROC. In addition, continued tank and evaporator emissions would occur simultaneously at the tank farms and the evaporator locations. Increased emissions would be expected from tanks undergoing retrieval. These increased emissions were modeled by assigning the highest increased emission rate for each pollutant to the TF6W Tank Farm, which was identified as the tank farm location producing the highest impacts. The actual emissions for every chemical would not necessarily be the highest at TF6W.
The emissions from the tank farms during retrieval operations would be the same as would be expected for retrieval activities associated with the operational phases of the Ex Situ (Intermediate Separations, No Separations, and Extensive Separations) alternatives. These impacts have been included with the analysis of these alternatives.
The second phase (replacement of the tanks 100 years in the future) is similar to the first phase, except that the routine and increased tank emissions would occur within the PROC area, as well as the construction emissions.
In Situ Fill and Cap Alternative
Implementing this alternative would involve construction and gravel-filling operations at the tank farm locations, as well as gravel removal from Pit 30.
For the purposes of the analysis, construction activities are assumed to occur simultaneously with the filling operations and routine emissions from the continued operation of the tank farms. The following text summarizes the pollutant emitting activities and sources for this alternative.
- Particulate matter emissions are expected as a result of gravel handling operations at Pit 30 (BTCH).
- Construction equipment emissions are expected at the tank farm location. To provide a conservative approach, emissions from construction activities were assigned to the bounding case location (TF6W).
- Gravel handling operations are assumed to occur at a location central to several tank farms; the corresponding emissions were assigned to location TF5W.
- Increased tank emissions during filling operations are expected. To ensure a conservative approach, the increased tank emissions were assigned to location TF6W in a similar manner as was done for retrieval operations.
The emissions from the tank farms during gravel filling operations would be the same as would be expected during the in situ portion of the Ex Situ/In Situ Combination 1 and 2 alternatives and have been included in the analysis of that alternative.
In Situ Vitrification Alternative
Implementing this alternative would involve constructing a tank farm confinement facility and an off-gas treatment facility at each tank farm. Construction of one confinement facility would occur while vitrification processes were occurring at an adjacent tank farm. For potential air quality impacts, the bounding case location for construction was identified as TF6W, and the impacts described are for this bounding case scenario.
Operations associated with this alternative would release pollutants that would be treated in an off-gas treatment facility. The emissions from the off-gas treatment facility would be from a vertical stack. The bounding case location for this operation was shown to be adjacent to TF6W. Although construction and operations activities would not occur at the same time and at the same tank farm location, the operational emissions were assigned to this location (IS6W) to provide a bounding case analysis.
Ex Situ Intermediate Separations Alternative
The construction phase would involve vehicular and fugitive dust emissions from constructing five waste transfer annexes and two waste processing facilities and constructing and operating a concrete batch plant to support these operations. Additionally, vehicular emissions associated with constructing tank waste retrieval equipment at the tank farms would occur during this time.
According to the estimated construction schedule, work would not be expected to occur at more than two tank farms at a time. An analysis was conducted to determine the two locations that would produce the highest impact when construction activities occurred simultaneously. It identified the TF5W and TF6W areas as having the highest combined impacts. Accordingly, the impacts of these activities were analyzed by assuming simultaneous construction operations at:
- The process facility locations;
- The concrete batch plant;
- The five transfer annex areas (TA1W, TA2W, TA3W, TA1E, TA2E); and
- Two tank farm locations (TF5W and TF6W).
The operational phase of the Ex Situ Intermediate Separations alternative would involve separating the waste into HLW and LAW streams and processing the waste at separate facilities. HLW vitrification processing would occur over a 12-year period while LAW processing would occur over a 19-year period. Additionally, retrieval equipment would operate at no more than two tank farm locations at a time during the course of the processing. Therefore, the impacts of the operations phase of the alternative were calculated by evaluating the simultaneous operation of both processing facilities (ST-L and ST-H) and the two tank farm locations (i.e., TF5W and TF6W) producing the highest impacts.
Ex Situ No Separations Alternative
The emission scenario for the Ex Situ No Separations alternative differs from the Ex Situ Intermediate Separations alternative because the tank waste would not be separated into LAW and HLW components and only one processing plant with one process stack (as opposed to two) would be operated. Two options (vitrification and calcination) were analyzed for this alternative. The sources and emission rates associated with the calcination option are identical to those of the vitrification alternative, with the exception of the emission rates of nitrogen oxides and carbon-14 (C-14) (Jacobs 1996).
The construction phase would involve vehicular and fugitive dust emissions from constructing the five waste transfer annexes and the process facilities, and from constructing and operating a concrete batch plant to support these operations. Additionally, vehicular emissions from erecting the retrieval equipment at the tank farms would occur during this time. These emissions were assigned in the same manner as described for the Ex Situ Intermediate Separations alternative construction phase, although emission rates would differ.
Operational processes for the Ex Situ No Separations alternative would occur over a 14-year period, beginning after completion of the construction phase. Emissions would occur through the main process stack at the vitrification facility. Additionally, installing and operating retrieval equipment would occur at only two tank farm locations at a time during processing. Therefore, the impacts of the operations phase of the alternative were calculated by evaluating the simultaneous operation of the process facility and the two tank farm locations (i.e., TF5W and TF6W) producing the highest combined impacts.
Ex Situ Extensive Separations Alternative
The construction phase would involve vehicular and fugitive dust emissions from constructing the five waste transfer annexes and the process facilities, and from constructing and operating a concrete batch plant to support these operations. Additionally, vehicular emissions from erecting the retrieval equipment at the tank farms would occur during this time. These emissions were assigned in the same manner as described for the Ex Situ Intermediate Separations alternative construction phase, although emission rates would differ.
The operational phase of this alternative would involve separating the tank waste into HLW and LAW streams and processing the waste at separate facilities. HLW and LAW processing vitrification processing would occur over a 21-year period. The off-gas emissions from these two processes would be combined and routed through a common stack (ESEP). In addition, retrieval equipment would be operated at only two tank farm locations at a time during processing. Therefore, the impacts of the operations phase of the alternative were calculated by evaluating the simultaneous operation of the process facilities (ESEP) and the two tank farm locations (i.e., TF5W and TF6W) producing the highest combined impacts.
Ex Situ/In Situ Combination 1 and 2 Alternative s
Implementing the in situ portion of these alternative s would involve the same source locations and emissions scenarios as described for the In Situ Fill and Cap alternative, although lower emission rates would be expected. These emissions would occur simultaneously with those associated with the operational phase of the ex situ portion of the alternative s .
The construction phase s would involve vehicular and fugitive dust emissions from constructing the waste transfer annexes and the process facilities, and from constructing and operating a concrete batch plant to support these operations. Additionally, vehicular emissions from erecting the retrieval equipment at the tank farms would occur during this time. These emissions were assigned in the same manner as described for the Ex Situ Intermediate Separations alternative construction phase, although emission rates would differ.
The operational phase of the ex situ vitrification portion of the alternative s would involve separating the HLW and LAW streams and processing the waste at separate facilities. Retrieval and ex situ vitrification operations would be expected to occur over a 21-year period for Combination 1, and over a 20-year period for Combination 2. Additionally, retrieval equipment would be expected to operate at no more than two tank farm locations at a time during processing. Therefore, the impacts of the operational phase of these alternative s were calculated by evaluating the simultaneous operation of both process facilities (ST-L and ST-H) and the two tank farm locations (i.e., TF5W and TF6W) producing the highest impacts.
Phased Implementation Alternative
Phase 1
Implementation of the first phase of this alternative would involve a construction period, during which two vitrification facilities would be constructed. Because construction on both facilities would occur simultaneously, the construction emissions were assigned to a single area source (FCPI) that would encompass the expected disturbed area.
Following completion of construction, operation of the two facilities would commence. Emissions from the vitrification processes would be released through two stacks -- one located at the combined LAW/HLW facility (NSPI), and one located at the LAW facility (SSPI). LAW operations at both plants would occur over a 10-year period; HLW operations at the combined plant would occur for 6 years. The impacts from these activities were calculated by using the peak hourly emission rates from all processes simultaneously.
Phase 2
In the second phase of this alternative, large-scale facilities would be constructed to treat the remainder of the tank waste. Emissions would come from constructing the five waste transfer annexes (TA1W, TA2W, TA3W, TA1E, TA2E), process facilities, and a concrete batch plant (BTCH). Emissions from erecting retrieval equipment at the tank farms producing the highest impacts (TF5W, TF6W) would occur simultaneously. These emissions were assessed in the same manner as described for the Ex Situ Intermediate Separations alternative.
Total Alternative
Impacts from the operation of the total Phased Implementation alternative are analyzed in the same manner as for the Ex Situ Intermediate Separations alternative. This involves the simultaneous operation of the two facilities discussed under Phase 1 (NSPI and SSPI), the large-scale facilities (ST-L 1, ST-L2 and ST-H), and the two tank farm locations producing the highest impacts (TF5W and TF6W).
G.2.2.2 Cesium and Strontium Capsule Alternatives
No Action Alternative (Capsules)
This alternative would involve maintaining the capsules at WESF. Routine radiological emissions from WESF were analyzed for this alternative and were included in the analysis of all other alternatives. These emissions were modeled as a point source (WESF). No other impacts are expected from this alternative.
Onsite Disposal Alternative
This alternative would involve transferring the existing capsules to a newly constructed Drywell storage facility. Constructing the Drywell storage facility would result in emissions from construction. These construction emissions were assigned to the source identified as DWSF. There would be no emissions during operations for this alternative. No airborne emissions are anticipated from the sealed Cs and Sr capsules while they are in storage. The only operational activities would be facility monitoring.
Overpack and Ship Alternative
This alternative would involve recovering the capsules from WESF, repackaging them, and shipping them to the potential geologic repository. A repackaging facility would be built as part of this alternative. Construction emissions and minor operational emissions would occur. These emissions were assigned to the area source identified as CPF.
Vitrify with Tank Waste Alternative
This alternative would involve recovering the Cs and Sr capsules from WESF, removing the contents, and vitrifying the capsule contents along with tank waste. Because the emissions occurring under this alternative are combined with emissions from remediating tank waste, no separate air quality impacts were analyzed.
G.3.0 MODEL SELECTION AND METHODOLOGY
Version two of the U.S. Environmental Protection Agency (EPA) Industrial Source Complex Model (ISC2) was selected to perform the air-dispersion modeling (EPA 1992a). The ISC2 model is a Gaussian dispersion model capable of simulating emissions from diverse source types. In a Gaussian dispersion model, pollutant concentrations are assumed to be distributed normally (i.e., bell-shaped curve) about the centerline of the plume, a relationship that has been observed to occur for releases of gases and small particles from many types of sources. ISC2 is a guideline air quality model (i.e., it is accepted by EPA for regulatory applications [40 CFR Part 51]). It is also routinely recommended for performing screening and refined analyses for remedial actions at Resource Conservation and Recovery Act and Superfund sites (EPA 1989a). This model was selected based on its widespread acceptability and versatility.
The ISC2 consists of two models: a short-term version (ISCST2) appropriate for predicting concentrations averages of 1 to 24 hours, and a long-term version (ISCLT2) for predicting seasonal and yearly concentrations. Both models were incorporated in this study. ISCLT2 was used to generate annual average predicted concentrations for comparison with annual average ambient air quality standards and target levels. ISCST2 was executed in a screening mode to predict short-term ambient air concentrations for comparisons to 1 to 24 hour average air quality standards and other target levels (EPA 1992b).
G.3.1 MODEL OPTIONS AND INPUTS
ISC2 requires the input of source and meteorological data as well as receptor coordinates (i.e., locations for which the model computes a concentration). The model must also be configured properly by the selection of various options. The following discussions document the inputs and model configuration.
G.3.1.1 Model Options
The models were run using the standard rural dispersion coefficients. These were selected based on the nature of the land use in the vicinity of the emission sources. Standard EPA procedures were followed in making this determination (40 CFR Part 51).
The regulatory default option was selected, which implemented the following model options:
- Final plume rise;
- Buoyancy-induced dispersion;
- Default wind profile exponents;
- Default vertical potential temperature gradients; and
- Upper bound values for supersquat buildings.
G.3.1.2 Source Data
The manner in which sources were grouped for each alternative is discussed in Section G.2.2. Source- related model input data are shown on Table G.3.1.1. Please note that all tables are located at the end of Appendix G. The chemical pollutant emission rates for each phase of the alternatives are shown in Tables G.3.1.2 through G.3.1.1 9 . Tables G.3.1. 20 through G.3.1. 31 contain the radiological emission rates. When appropriate, construction and operational emissions from the alternatives were analyzed separately, and separate emissions data for construction and operational activities are reported. In other cases, construction and operational processes would occur simultaneously, and the emission rates reported represent the combined emissions from construction and operational activities.
The primary sources of data used for the emission rates were the engineering data packages for the various alternatives, which were prepared by the Hanford Site Management and Operations contractor (WHC 1995 a, b, c, d, e, f, g, h, i, n) and the TWRS EIS contractor (Jacobs 1996). The following discussion describes the protocol used for calculating model emission rates from the available data.
Routine Emissions from Tank Farms and the Waste Encapsulation and Storage Facility
Routine emissions of radiological and nonradiological components from continued operations of the tank farms and WESF are shown for the No Action alternative (Tank Waste) in Tables G.3.1.2 and G.3.1. 20 . Emissions are reported separately for each tank farm location (Jacobs 1996). Similar emissions are expected to occur and were analyzed for all alternatives. However, during retrieval operations (and during gravel filling operations associated with the In Situ Fill and Cap alternative), the routine emissions rates would be expected to increase at the affected tank farm location. In these situations, the increased emission rates were analyzed in the following manner: the highest routine emission rate for each pollutant was assigned to source TF6W to provide a bounding case scenario and increased by the appropriate factor to represent retrieval or gravel filling operations.
In Situ Vitrification Emission Data
Data contained in the engineering data packages for this alternative were analyzed to generate tables of radiological and nonradiological emissions for this alternative (Jacobs 1996). Separate emissions data for the construction and operational phases for the alternative were created. Annual construction emissions were converted to peak hourly emissions based on an assumed schedule of construction activities. The peak hourly emission rate of each pollutant for the vitrification process was used for the model input.
Process Facility Stack Emissions Data
Process flow diagrams and mass balance data contained in the engineering data packages were analyzed to generate tables of average annual emissions, maximum daily emissions, and peak hourly emissions from the vitrification facility process stacks for the Ex Situ Intermediate Separations, Ex Situ No Separations, and Ex Situ Extensive Separations alternatives, including the Ex Situ/In Situ Combination 1 and 2 and the Phased Implementation alternatives (Jacobs 1996). The peak hourly emissions for pollutants listed in these tables were used to generate emission rates for the process stacks.
Construction Activities Emission Data
The primary sources of construction activity emission data were the engineering data packages for the various alternatives. In some cases, data concerning the construction emissions were not given explicitly in the data package. Calculations were performed to estimate the emissions given the scope of the construction activity (Jacobs 1996). Annual emissions were converted to hourly emissions based on an assumed schedule for construction activities.
G.3.1.3 Meteorological Data
Long-Term Meteorological Data
The meteorological data used for the ISCLT2 model consisted of a joint frequency distribution, also referred to as a stability array (STAR) of wind speed, wind direction, and stability class compiled for each of 5 years (1989 to 1993). The stability arrays are shown in Tables G.3.1.33 through G.3.1.37. These data were based on measurements collected at the Hanford Meteorological Station located between the 200 East Area and 200 West Area (PNL 1994g). The general wind direction is to the southeast.
Additional meteorological data, such as the annual mean temperature and mixing heights, were obtained from the Hanford Climatological Data Summary (PNL 1994g) and a standard summary document of morning and afternoon mixing heights (Holzworth 1972). The protocol for assigning these values was taken from the ISC2 User's Manual (EPA 1992a). As outlined in the user's manual, the average annual maximum daily temperature (18 C [65 F]) was used for the A, B, and C stability classes; the average minimum daily temperature (5 C [42 F]) was used for the stability classes E and F; and the average annual temperature (12 C [53 F]) was used for the D stability class. Mixing height values were assigned as follows: 1.5 times the average afternoon mixing height of 1,500 m (4,900 ft) was used for stability class A and the average afternoon mixing height was used for stability classes B, C, and D. Because ISCLT2 in the rural mode assumes that there is no restriction in vertical mixing in the E and F stability classes, 1.5 times the average afternoon mixing height was considered to be appropriate for these stability classes.
Short-Term Meteorological Data
ISCST2 requires hourly meteorological data. Typically, for refined and regulatory modeling, a full year of sequential hourly records are input to the model. Because data in this format for the Hanford Site were unavailable and a refined level of modeling was not considered necessary given the preliminary nature of the design data, the ISCST2 model was executed in a screening mode. This required inputting a range of possible meteorological conditions which might reasonably occur at this site. This screening meteorological file was prepared according to procedures outlined in EPA's SCREEN2 Model User's Guide (EPA 1992c).
For each of 36 wind directions, 54 possible combinations of stability class and wind speed were input (i.e., 1,944 hourly records). A matrix of windspeed and stability classes is shown in Table G.3.1. 32 .
Atmospheric mixing heights were assigned to stability classes A, B, C, and D using the mechanical mixing height (Zm) and calculated using the following formula taken from Section 3.2 of the SCREEN2 Model User's Guide:
Where:
Zm = mechanical mixing height (m)
u10 = wind speed at 10 m elevation (m/s)
To allow for unlimited mixing, heights of 10,000 m (32,800 ft) were assigned to stability classes E and F, in keeping with the scheme outlined in the SCREEN2 User's Manual. Ambient temperatures for each stability class were assigned in the same manner as the ISCLT2 model inputs.
G.3.1.4 Receptor Locations
Three receptor sets were used for the study. The first set was used to predict concentrations for comparison with Washington State and Federal ambient air quality standards and target levels for nonradionuclide impacts, and for comparison with the Washington State ambient air quality standard for radionuclides. These receptor locations were placed to correspond to areas that might be considered to be ambient air (i.e., areas where the general public could be exposed). Because of the potential release of the Fitzner Eberhardt Arid Lands Ecology portion of the Hanford Site, the public would have access to land southwest of State Route 240, and it was selected to represent the southern boundary of the facility. For the same reason, the Columbia River was selected to define the northern and eastern facility boundaries. A total of 614 receptors were placed along the Columbia River, State Route 240, and the Hanford Site boundary line north of the Columbia River. Because of the size of the Hanford Site, most offsite receptors are quite distant from the sources and were placed with a 2-km (1.2-mi) spacing. To ensure that the areas of maximum impact were identified, receptors were placed at 500-m (1,650-ft) intervals along sections of State Route 240 to ensure adequate coverage.
The second set of receptors was used to assess compliance with the Federal standard for radionuclide release impacts contained in 40 Code of Regulations [CFR] Part 61. Compliance with this standard is calculated at the nearest residence, rather than at the nearest ambient air location. Although the distance from the source locations to the nearest residence in all directions is not known, available data indicate that no residence lies within 24 km (15 mi) of the 200 West area, or 16 km (10 mi) of the 200 East Area (DOE 1994d). Thus, a circular set of 72 receptors, centered on the 200 West Area and with a radius of 24 km (15 mi), was established to assess compliance with this standard. This circular grid encompasses all locations within 16 km (10 mi) of the 200 East Area.
A rectangular grid of 834 receptors, which encompasses the entire Hanford Site, was used to generate isopleths of radionuclide impacts.
ISC2 is designed to model simple terrain (i.e., terrain less than or equal to stack height). Terrain elevation is relevant for modeling point sources. Concentration predictions from area source emissions are not affected by terrain. Elevations for all receptor locations were obtained from a Geographic Information System database of the Hanford Site and U.S. Geological Survey topographical maps of the surrounding area.
G.3.2 MODEL OUTPUT
The model output consisted of ground level average concentration values. ISCLT2 produced annual average concentrations for each of the 5 years (1989 to 1993) of meteorological input data. The predicted concentrations reported are from the year producing the highest impact. ISCST2 was executed to determine the maximum 1-hour average concentrations resulting from inputting a range of possible meteorological conditions. The 1-hour averages were multiplied by various correction factors for predictions of 3-, 8-, and 24-hour average concentrations. The following sections provide more details on the concentration calculations.
G.3.2.1 Normalized Concentrations
To provide efficiency in processing the results and flexibility for incorporating future changes, the sources were modeled with unit emission rates, resulting in predictions of normalized concentrations (also referred to as Chi/Q values).
The normalized concentrations, having dimensions of 1.0E-06 seconds/cubic meter (s/m3), were produced by assigning each source a unit emission rate of 1.0 grams per second (g/s). The concentration at a receptor was calculated by multiplying the actual emission rate (referred to as the source term) by the appropriate Chi/Q value. For example, a source term expressed in units of g/s will produce a concentration given as micrograms per cubic meter (µg/m3), and a source term expressed in units of curies per second (Ci/s) will produce a concentration given as µCi/m3.
The total concentration at any receptor consists of the sum of the concentrations contributed by each emitting source. Therefore, the total concentration at a receptor with n contributing sources is calculated as follows:
Where:
Ctotal = total concentration (µg/m3
or µCi/m3)
(Chi/Q)n = predicted Chi/Q value
(1.0E-06 s/m3) for source n
T = source term (g/s or
Ci/s) for source n
Separate Chi/Q plot files were generated for each of the 30 identified sources. To calculate the total concentration values these plot files have been entered into spreadsheets. These spreadsheets allow the input of source terms of interest for each pollutant and the calculation of total concentration values at each receptor location.
G.3.2.2 Averaging Time Conversions
Values for 3-, 8-, and 24-hour averages were obtained by multiplying the calculated 1-hour average concentration by the following conversion factor: 0.9 for 3-hour averages, 0.7 for 8-hour averages, and 0.4 for 24-hour averages (EPA 1992b).
G.4.0 MODEL RESULTS
The results of the modeling were compared with Washington State air quality standard or acceptable source impact levels. Washington State standards are listed in the Washington Administrative Code (WAC) and include:
- Acceptable Source Impact Levels for toxic air pollutants (WAC 173-460);
- Ambient Air Quality Standards for particulate matter (WAC 173-470);
- The Ambient Air Quality Standards for sulfur oxides (WAC 173-474);
- The Ambient Air Quality Standards for carbon monoxide ozone and nitrogen dioxide (WAC 173-474);
- The Ambient Air Quality Standards for radionuclides (WAC 173-480); and
- The Ambient Air Quality Standards for fluorides (WAC 173-481).
The results were also compared with national primary and secondary Ambient Air Quality Standards listed in 40 CFR Part 50. The Washington Ambient Air Quality Standards are equal to or are more stringent than the National Ambient Air Quality Standards, and thus compliance with the Washington Ambient Air Quality Standards implies compliance with the National Ambient Air Quality Standards.
Predicted maximum emissions for hazardous air pollutants and pollutants for which a Washington Acceptable Source Impact Level exists are provided along with the applicable level. Modeling results for chemical pollutants are given in Tables G.4.0.1 through G.4.0. 20 . Modeled impacts for key radionuclides during operations are plotted in Figures G.4.0.1 through G.4.0. 13 and presented for each alternative in Tables G.4.0. 21 through G.4.0. 32 . The modeling results show radionuclide emissions converted to doses and compares them to Washington Air Quality Standards for radiation doses contained in WAC 173-480 and Federal standards for radioactive emissions from DOE facilities (40 CFR 61, Subpart H). The Ambient Air Quality Standard (WAC 173-480) for the maximum accumulated dose equivalent at any offsite receptor from a commercial nuclear facility is 25 mrem/yr. As a Federal facility, the Hanford Site could be expected to comply with the EPA regulation (40 CFR 61), which limits the maximum predicted dose at the nearest residence to 10 mrem/yr dose equivalent. Uranium-235 (U-235) was not included in the impacts for radionuclides. Uranium trioxide was, however, analyzed as a hazardous air pollutant. This approach is consistent with the risk analysis for routine operations for each alternative, because the chemical toxicity of uranium is much greater than its radiological hazard. Additionally, emissions of U-235 were determined to have a very small contribution to overall risk.
The modeling results for all alternatives show no exceedances of Federal or State air quality standards for criteria pollutants, hazardous air pollutants, or radionuclides. Substantial impacts from all sources (those that exceed 10 percent of the applicable standard) are listed in the following text:
| Particulates | The impacts, as a percentage of the Federal and State 24-hour standard, that would occur during the construction phases of the In Situ Vitrification alternative (64 percent of the standard) and the construction phases of the Ex Situ Extensive Separations, Ex Situ Intermediate Separations, and Ex Situ No Separations) alternatives (63 percent, 62 percent, and 57 percent, respectively). In addition, substantial impacts occur during the construction phases of the Ex Situ/In Situ Combination 1 and 2 alternatives (34 percent of the 24-hour State and Federal standards), the Phased Implementation Phase 1 alternative (58 percent of the State and Federal 24-hour standard), Phased Implementation Phase 2 (65 percent of the State and Federal 24-hour standard) and the Capsules Onsite Disposal alternative (12 percent of the State and Federal 24-hour standard). |
| Carbon Monoxide | The impacts, as a percentage of the Federal and State 8-hour standard, that would occur during the construction phases of the Ex Situ Extensive Separations, Ex Situ Intermediate Separations, and Ex Situ No Separations alternatives are 25 percent, 21 percent, and 17 percent, respectively. |
| Sulfur Oxides | The impacts, as a percentage of the State 1-hour standard, that would occur during the In Situ Vitrification alternative are 10 percent of the standard. |
| Radionuclides | The impacts, as a percentage of the State annual standard, that would occur during the In Situ Vitrification alternative are 75 percent of standard, with primary contributors being C-14 and iodine-129 (I-129). |
| The impacts, as a percentage of the Federal annual standard, that would occur during the In Situ Vitrification alternative are 24 percent of standard, with primary contributors being C-14 and I-129. |
G.5.0 ACCURACY AND UNCERTAINTY
Various assumptions and other factors can introduce uncertainty in air dispersion modeling studies. With regard to the modeling performed to analyze air impacts from the various alternatives, these uncertainties can be broadly separated into the following categories:
- Uncertainty inherent in the air dispersion models;
- Uncertainty in data used as model inputs; and
- Uncertainty in interpretation of model output.
These categories are discussed in more detail in the following text.
G.5.1 AIR DISPERSION MODELING
Air dispersion models are mathematical tools designed to estimate pollutant concentration and/or deposition at specific locations. These predictions are based on various input parameters and physical assumptions, such as the following:
- Pollutant release characteristics (emission rate, temperature, flow rate);
- Meteorological conditions (ambient temperature, mixing height, stability, wind speed and direction, atmospheric temperature and wind speed profile); and
- Pollutant transport behavior (dispersion, plume rise, interaction with terrain).
In an ideal case, the values entered into the model for these known parameters will closely duplicate the range of actual conditions that exist for a particular scenario. However, the stocastic nature of the atmosphere results in other unknown factors (e.g., wind perturbations) that influence the actual dispersion at a particular time or place. It has been estimated that even when the known conditions are exactly duplicated in the model, the unknown factors can contribute to variations in concentration as much as ±50 percent (EPA 1995).
Gaussian air dispersion models are accurate within a factor of two when properly executed with accurate data. In general, models are more reliable when estimating long-term average concentrations as opposed to short-term averages, and are reasonably reliable in estimating the magnitude of the highest concentration occurring, but are not capable of predicting the exact time or position of the occurrence. In other words, the highest concentration that can be expected in an area can be predicted with reasonable accuracy; the location and time that the maximum concentration will occur are less reliably predicted.
The air dispersion models used in this study are considered to be state-of the-art for regulatory modeling and are recommended by EPA for this type of analysis. To compensate for the uncertainties in model results, conservative input values were used that provide conservative (higher than might actually occur under average conditions) results.
G.5.2 MODEL INPUT DATA
Two types of input data are used for the air dispersion models: meteorological data and source data. Both types of input data are discussed in the following text.
G.5.2.1 Meteorological Data
Two types of meteorological data (i.e., long-term and short-term) were used in the dispersion modeling study. Long-term (i.e., annual) average concentrations were estimated using meteorological data collected at the Hanford Meteorological Station from 1989 to 1993. The assumption inherent in this choice is that this data represent future meteorological conditions. A 5-year record is generally accepted as an adequate sample set for modeling purposes. Although long-term climatic shifts may occur, many of the air pollutant emitting activities analyzed in this study are expected to occur within several decades of project initiation, which is a relatively short time frame on a climatic scale. Therefore, the use of this data is not expected to adversely affect the results.
Typically, short-term average (i.e., 1- 3- 8- and 24-hour) concentrations are predicted using hourly meteorological measurements from a station located at, or near, the site of interest. Because the data were not available for this study, a screening approach was taken, and a standard set of hourly meteorological conditions were incorporated in the modeling. These standard conditions are accepted by the EPA to encompass the range of atmospheric stabilities and wind speeds that could be expected to occur anywhere. Each combination of wind speed and atmospheric stability was assumed to occur in every possible wind direction. The predicted concentrations represent the highest value that could be reasonably expected to occur anywhere. This approach is conservative because the meteorological condition leading to the reported result may not occur at the site for all wind directions.
G.5.2.2 Source Data
Data describing the location, emission rate, and emission characteristics of the sources was input to the models. Information concerning pollutant emission rates was derived from data packages supplied by the Site Management and Operations contractor and analyzed by the Environmental Impact Statement contractor. In general, when emissions estimates were being developed, conservative values were used.
The location of the pollutant emitting sources is not known with complete certainty in all cases. Pollutant emitting activities associated with the existing tank farms will occur in the present locations. However, the exact location of future facilities is subject to some uncertainty. In general, the closer a source is to a receptor, the higher the predicted concentration at that receptor will be. As a consequence, if the eventual location of an emitting activity is closer to a plant boundary than depicted in the model, the impacts may be higher. Of course, if the activity is located farther from the boundary than depicted in the model, the impacts may be lower.
The temporal arrangement of the pollutant emitting activities affects the predicted concentrations as well. The predicted concentration at any receptor represents the contributions of each individual emitting source. To properly analyze a scenario, all the pollutant emitting activities that could occur at the same time must be considered. In general, most of the scenarios analyzed involved a period of facility construction followed by an operational period.
In some cases, the location of an emitting source is expected to move from place to place as the project progresses. An example of this would be emissions related to remedial activities at tank farm locations. In most cases, work would be occurring at one or two of the possible 17 locations at one time. Given these uncertainties, a conservative analysis was produced by assuming that activities that might or might not overlap in time would occur simultaneously. In addition, activities that would be expected to move from place to place were modeled as if occurring in the location producing the highest potential impact.
Sources were modeled as either point or area sources. Point sources are used to approximate pollutant releases from a stack or other fixed, functional opening or vent. The dispersion algorithms used for point sources modify the effective release height to take into account plume buoyancy (from a heated release) and momentum (from vertical release velocity). Typically, area sources are used to approximate pollutant releases that do not occur at a single well-defined point, but instead can be defined as occurring within a defined area. For instance, an area source could include many small fixed point sources that were too numerous to model individually, or could made up of several mobile sources that may move about within the fixed area. In this study, the construction activities were represented as area sources. The classification of the sources into these two categories involved some degree of uncertainty and some assumptions as well. The models use different algorithms to represent dispersion from point and area sources and the predicted concentration at a receptor could vary, depending on the algorithm chosen. In general, these effects are more noticeable at locations close to the source and tend to diminish as the distance between source and receptor increases.
G.5.3 INTERPRETATION OF MODEL OUTPUT
The short-term model was run using screening meteorology to produce maximum predicted 1-hour average concentrations. These 1-hour average values were converted to 3- ,8-, and 24-hour average concentrations, when appropriate, to compare to applicable standards. This was accomplished by applying conversion factors to the 1-hour average values. Consistent with modeling guidelines (EPA 1988), the factors of 0.9, 0.7, and 0.4 were applied to convert to 3-, 8-, and 24-hour averages, respectively. These factors involve an implied assumption regarding the persistence of the meteorological condition producing the highest 1-hour impact. In other words, conservative meteorological conditions that produced the highest 1-hour concentration can be expected to persist for most of a 3-hour period and to a lesser degree over an 8- or 24-hour period. The modeling guidelines indicate a range of values for each conversion factor: the 3-hour conversion factor can range from 0.8 to 1.0, the 8-hour factor from 0.5 to 0.9, and the 24-hour factor from 0.2 to 0.6. Use of the midpoint values was considered appropriate for this study.
FIGURES:
Figure G.4.0.1 Radionuclide Dose (mrem/yr) for the No Action Alternative
Figure G.4.0.2 Radionuclide Dose (mrem/yr) for the Long-Term Management Alternative (Phase 1)
Figure G.4.0.3 Radionuclide Dose (mrem/yr) for the Long-Term Management Alternative (Phase 2)
Figure G.4.0.4 Radionuclide Dose (mrem/yr) for the In Situ Fill and Cap Alternative
Figure G.4.0.5 Radionuclide Dose (mrem/yr) for the In Situ Vitrification Alternative
Figure G.4.0.6 Radionuclide Dose (mrem/yr) for the Ex Situ Intermediate Separations Alternative
Figure G.4.0.8 Radionuclide Dose (mrem/yr) for the Ex Situ No Separations Alternative (Calcination)
Figure G.4.0.9 Radionuclide Dose (mrem/yr) for the Ex Situ Extensive Separations Alternative
Figure G.4.0.10 Radionuclide Dose (mrem/yr) for the Ex Situ/In Situ Combination 1 Alternative
Figure G.4.0.11 Radionuclide Dose (mrem/yr) for the Ex Situ/In Situ Combination 2 Alternative
Figure G.4.0.12 Radionuclide Dose (mrem/yr) for the Phased Implementation Alternative - Phase 1
Figure G.4.0.13 Radionuclide Dose (mrem/yr) for the Phased Implementation Alternative - Phase 2
TABLES:
Table G.3.1.1 Source Locations and Parameters
Table G.3.1.2 Emission Rates for the No Action Alternative (Tank Waste)
Table G.3.1.3 Emission Rates for the Long-Term Management Alternative Phase 1 (First Retanking)
Table G.3.1.4 Emission Rates for the Long-Term Management Alternative Phase 2 (Second Retanking)
Table G.3.1.5 Emission Rates for the In Situ Fill and Cap Alternative
Table G.3.1.6 Emission Rates for the In Situ Vitrification Alternative
Table G.3.1.8 Emission Rates for the Ex Situ Intermediate Separations Alternative - Operation Phase
Table G.3.1.9 Emission Rates for the Ex Situ No Separations Alternative - Construction Phase
Table G.3.1.10 Emission Rates for the Ex Situ No Separations Alternative - Operation Phase
Table G.3.1.11 Emission Rates for the Ex Situ Extensive Separations Alternative - Construction Phase
Table G.3.1.12 Emission Rates for the Ex Situ Extensive Separations Alternative - Operation Phase
Table G.3.1.15 Emission Rates for the Ex Situ/In Situ Combination 2 Alternative - Operation Phase
Table G.3.1.16 Emission Rates for the Phased Implementation Alternative Phase 1 - Construction Phase
Table G.3.1. 17 Emission Rates for the Phased Implementation Alternative Phase 1 - Operation Phase
Table G.3.1. 19 Emission Rates for the Phased Implementation Alternative Phase 2 - Operation Phase
Table G.3.1. 20 Radionuclide Emission Rates for the No Action Alternative (Tank Waste)
Table G.3.1. 21 Radionuclide Emission Rates for the Long-Term Management Alternative Phase 1
Table G.3.1. 22 Radionuclide Emission Rates for the Long-Term Management Alternative Phase 2
Table G.3.1. 23 Radionuclide Emission Rates for the In Situ Fill and Cap Alternative
Table G.3.1. 24 Radionuclide Emission Rates for the In Situ Vitrification Alternative
Table G.3.1. 25 Radionuclide Emission Rates for the Ex Situ Intermediate Separations Alternative
Table G.3.1. 26 Radionuclide Emission Rates for the Ex Situ No Separations Alternative
Table G.3.1. 27 Radionuclide Emission Rates for the Ex Situ Extensive Separations Alternative
Table G.3.1. 28 Radionuclide Emission Rates for the Ex Situ/In Situ Combination 1 Alternative
Table G.3.1. 29 Radionuclide Emission Rates for the Ex Situ/In Situ Combination 2 Alternative
Table G.3.1. 30 Radionuclide Emission Rates for the Phased Implementation Alternative Phase 1
Table G.3.1. 31 Radionuclide Emission Rates for the Phased Implementation Alternative Phase 2
Table G.3.1. 32 Matrix of Wind Speed and Stability Classes
Table G.3.1. 33 Stability Array for Year 1989
Table G.3.1. 34 Stability Array for Year 1990
Table G.3.1. 35 Stability Array for Year 1991
Table G.3.1. 36 Stability Array for Year 1992
Table G.3.1. 37 Stability Array for Year 1993
Table G.4.0.1 Modeling Results for the No Action Alternative (Tank Waste)
Table G.4.0.2 Modeling Results for the Long-Term Management Alternative Phase 1
Table G.4.0.3 Modeling Results for the Long-Term Management Alternative Phase 2
Table G.4.0.4 Modeling Results for the In Situ Fill and Cap Alternative
Table G.4.0.5 Modeling Results for the In Situ Vitrification Alternative
Table G.4.0.8 Modeling Results for the Ex Situ No Separations Alternative - Construction Phase
Table G.4.0.9 Modeling Results for the Ex Situ No Separations Alternative - Operation Phase
Table G.4.0.11 Modeling Results for the Ex Situ Extensive Separations - Operation Phase
Table G.4.0.13 Modeling Results for the Ex Situ/In Situ Combination 1 Alternative - Operation Phase
Table G.4.0.1 4 Modeling Results for the Ex Situ/In Situ Combination 2 Alternative - Operation Phase
Table G.4.0.1 6 Modeling Results for the Phased Implementation Alternative Phase 1 - Operation Phase
Table G.4.0. 18 Modeling Results for the Phased Implementation Alternative Phase 2 - Operation Phase
Table G.4.0. 19 Modeling Results for the Onsite Disposal Alternative
Table G.4.0. 20 Modeling Results for the Overpack and Ship Alternative
Table G.4.0. 21 Radionuclide Modeling Results for the No Action Alternative (Tank Waste)
Table G.4.0. 22 Radionuclide Modeling Results for the Long-Term Management Alternative Phase 1
Table G.4.0. 23 Radionuclide Modeling Results for the Long-Term Management Alternative Phase 2
Table G.4.0. 24 Radionuclide Modeling Results for the In Situ Fill and Cap Alternative
Table G.4.0. 25 Radionuclide Modeling Results for the In Situ Vitrification Alternative
Table G.4.0. 26 Radionuclide Modeling Results for the Ex Situ Intermediate Separations Alternative
Table G.4.0. 27 Radionuclide Modeling Results for the Ex Situ No Separations Alternative
Table G.4.0. 28 Radionuclide Modeling Results for the Ex Situ Extensive Separations Alternative
Table G.4.0. 29 Radionuclide Modeling Results for the Ex Situ/In Situ Combination 1 Alternative
Table G.4.0. 30 Radionuclide Modeling Results for the Ex Situ/In Situ Combination 2 Alternative
Table G.4.0. 31 Radionuclide Modeling Results for the Phased Implementation Alternative Phase 1
Table G.4.0. 32 Radionuclide Modeling Results for the Phased Implementation Alternative Phase 2
REFERENCES
40 CFR Part 51. Requirements for Preparation, Adoption, and Submittal of Implementation Plans. U.S. Environmental Protection Agency. Code of Federal Regulations, as amended. 1995.
40 CFR 61. National Emission Standards for Hazardous Air Pollutants. U.S. Environmental Protection Agency. Code of Federal Regulations, as amended. 1995.
DOE 1994d. Radionuclide Air Emission Report for the Hanford Site Calendar Year 1993. DOE/RL-94-15. U.S. Department of Energy. Richland, Washington. 1994
EPA 1992a. User's Guide for the Industrial Source Complex ISC2 Dispersion Models. EPA-450/1-89-004. U.S. Environmental Protection Agency. Research Triangle Park, North Carolina. 1992.
EPA 1992b. A Workbook of Screening Techniques for Assessing Impacts of Toxic Air Pollutants. EPA-450/4-92-006. U.S. Environmental Protection Agency. Research Triangle Park, North Carolina. 1992.
EPA 1992c. SCREEN2 Model User's Guide. EPA-450/4-92-006. U.S. Environmental Protection Agency. Research Triangle Park, North Carolina. 1992.
EPA 1989a. Air/Superfund National Technical Guidance Study Series: Volume IV- Procedures for Dispersion Modeling and Air Monitoring for Superfund Air Pathway Analysis. EPA-450/4-92-008. U.S. Environmental Protection Agency. Research Triangle Park, North Carolina. July 1989.
Holzworth 1972. Holzworth, G.C. Mixing Heights, Wind Speeds, and Potential for Urban Air Pollution Throughout the Contiguous United States. U.S. Environmental Protection Agency. Research Triangle Park, North Carolina. 1972.
Jacobs 1996. Engineering Calculations for the Tank Waste Remediation System Environmental Impact Statement. Jacobs Engineering Group Inc. Kennewick, Washington. April 1996.
PNL 1994g. Hanford Site Climatological Data Summary, 1993, with Historical Data. PNL-9809. Pacific Northwest National Laboratory. Richland, Washington. June 1994
WAC 173-400 through 173-495. Washington State Air Pollution Control Regulations. Washington Administrative Code. Olympia, Washington.
WHC 1995a. Other Options Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-EV-106, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995b. Historical Tank Content Estimate for the Northwest Quadrant of the Hanford 200 West Area. WHC-SD-WM-ER-351. Westinghouse Hanford Company. Richland, Washington. March 1995.
WHC 1995c. No Separations Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-EV-103, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995d. Single-Shell and Double-Shell Tank Waste Inventory Data Package for the Tank Waste Remediation Environmental Impact Statement. WHC-SD-WM-EV-102, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995e. Extensive Separations Pretreatment Alternative Engineering Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-EV-100, Rev. 0. Westinghouse Hanford Company. Richland, Washington. September 1995.
WHC 1995f. In Situ Treatment and Disposal of Radioactive Waste in Hanford Site Underground Storage Tanks Engineering Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-EV-101, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995g. No Disposal Action Engineering Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-EV-099, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995h. Disposition of Cs and Sr Capsules Engineering Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-DP-087, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995i. Closure Technical Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-EV-107, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995j. Tri-Party Agreement Alternative Engineering Data Package for the Tank Waste Remediation System Environmental Impact Statement. WHC-SD-WM-EV-104, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
WHC 1995n. Waste Retrieval and Transfer Engineering Data Package for the TWRS EIS. WHC-SD-WM-EV-097, Rev. 0. Westinghouse Hanford Company. Richland, Washington. July 1995.
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