EA-1164; Environmental Assessment for Closure of the High-Level Waste Tanks in F-

This Environmental Assessment (EA) has been prepared by the Department of Energy (DOE) to assess the potential environmental impacts associated with the closure of 51 high level radioactive waste tanks and tank farm ancillary equipment (including transfer lines, evaporators, filters, pumps, etc) at the Savannah River Site (SRS) located near Aiken, South Carolina (Figure 1-1). The waste tanks are located in the F- and H-Areas (Figures 1-2 and 1-3) of SRS and vary in capacity from 2,839,059 liters (750,000 gallons) to 4,921,035 liters (1,300,000 gallons). These in-ground tanks are surrounded by soil to provide shielding.

The F- and H-Area High-Level Waste Tanks are operated under the authority of Industrial Wastewater Permits #17,424-IW, #14520, and #14338 issued by the South Carolina Department of Health and Environmental Control (SCDHEC). In accordance with the Permit requirements, DOE has prepared a Closure Plan (DOE, 1996) and submitted it to SCDHEC for approval. The Closure Plan identifies all applicable or relevant and appropriate regulations, statutes, and DOE Orders for closing systems operated under the Industrial Wastewater Permits. When approved by SCDHEC, the Closure Plan will present the regulatory process for closing all of the F- and H-Area High Level Waste Tanks. The Closure Plan establishes performance objectives or criteria to be met prior to closing any tank, group of tanks, or ancillary tank farm equipment.

The proposed action is to remove the residual wastes from the tanks and to fill the tanks with a material to prevent future collapse and bind up residual waste, to lower human health risks, and to increase safety in and around the tanks. If required, an engineered cap consisting of clay, backfill (soil), and vegetation as the final layer to prevent erosion would be applied over the tanks. The selection of tank system closure method will be evaluated against the following Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) criteria described in 40 CFR 300.430(e)(9): (1) overall protection of human health and the environment; (2) compliance with applicable or relevant and appropriated requirements (ARARs); (3) long-term effectiveness and permanence; (4) reduction of toxicity, mobility, or volume through treatment; (5) short-term effectiveness; (6) implementability; (7) cost; (8) state acceptable; and (9) community acceptance.

Closure of each tank involves two separate operations after bulk waste removal has been accomplished: 1) cleaning of the tank (i.e., removing the residual contaminants), and 2) the actual closure or filling of the tank with an inert material, (e.g., grout). This process would continue until all the tanks and ancillary equipment and systems have been closed. This is expected to be about year 2028 for Type I, II, and IV tanks and associated systems. Subsequent to that, Type III tanks and systems will be closed.

Thus, the 24 Type I, II, and IV tanks would be removed from service while the 27 Type III tanks would remain in service until there is no further need for the tanks or the wastes have been consolidated into other tanks. When waste processing is complete and the last tank closed, the remaining waste processing systems would be closed.

The environmental impacts of operation of the tank farms, including bulk waste removal, are evaluated in the Defense Waste Processing Facility Supplemental Environmental Impact Statement (DOE, 1994) and the Waste Management Environmental Impact Statement (DOE, 1995a). Potential impacts to the soil from contaminants already present around the sides of the tanks or under the tanks from previous leaks or spills are not addressed in this EA as they are already covered under CERCLA. Remediation of these impacts would be evaluated in other environmental restoration activities scheduled for the site.

This document was prepared in compliance with the National Environmental Policy Act (NEPA) of 1969, as amended, the Council on Environmental Quality Regulations for Implementing NEPA (40 CFR 1500-1508), and the DOE Regulation for implementing NEPA (10 CFR 1021). NEPA requires the assessment of environmental consequences of Federal actions that may affect the quality of the human environment. Based on the potential for impacts described herein, DOE will either publish a Finding of No Significant Impact (FONSI) or prepare an Environmental Impact Statement (EIS).

1.1 Background

When established in the early 1950s, SRS's primary mission was to produce special nuclear materials to support the defense, research, and medical programs of the United States. SRS's present mission emphasizes waste management, environmental restoration, and decontamination and decommissioning of facilities that are no longer needed for SRS's traditional defense mission. Chemical separation of irradiated fuel and targets at SRS resulted in product streams and acidic liquid streams that contained almost all of the fission products and small amounts of transuranics. This waste was chemically converted to an alkaline solution and stored in large underground tanks at the SRS F- and H-Area Tank Farms (Figures 1-2 and 1-3) as insoluble sludges, precipitated salts, and supernate (liquid) (DOE, 1982).

At the present time the approximately 129 million liters (34 million gallons) of High-Level Waste (HLW) are being treated to separate the high-activity fraction (a sludge) from the low activity fraction (a liquid). The high-activity fraction is transferred to the Defense Waste Processing Facility (DWPF) for vitrification in borosilicate glass to immobilize the radioactive constituents for long term storage. Final disposal of the vitrified waste will proceed after the transfer to a federal repository. The low-activity fraction is transferred to Z Area and mixed with grout to make saltstone, a concrete-like material disposed of in vaults. The environmental impacts of these processes and facilities were evaluated in the DWPF Supplemental Environmental Impact Statement (DOE, 1994) and Waste Management Environmental Impact Statement (DOE, 1995a). A more detailed description of the systems and processes of interest is provided in Appendix A, High-Level Waste System Description in this EA and in the above referenced EISs (DOE, 1994; DOE, 1995a).

After the bulk waste has been removed from the tanks for treatment and disposal, the tank systems would become part of the tank systems closure project (Figure 1-4), the potential environmental impacts of which are the subject of this EA. The primary concerns are how to deal with the waste that cannot be removed from the bottom of a tank (referred to as a heel) and tank stabilization methods. As outlined in the Closure Plan (DOE, 1996), DOE intends to close the tank systems to protect human health and the environment, and promote safety in and around these tank systems in accordance with South Carolina Regulation R.61-82, "Proper Closeout of Wastewater Treatment Facilities".

Upon completion of closure activities for geographical groups of tanks and waste handling systems, including evaporators, pumps, and transfer lines under this plan, portions of the High-Level Waste (HLW) tank farms would transition from the tank closure project to the SRS Environmental Restoration program.

1.2 Purpose and Need for Action

The purpose of DOE's proposed action is to close the 51 HLW tanks in the F- and H-Area Tank Farms, after the current bulk waste inventory has been removed, to lower human health risks and to increase safety in and around the tanks. If the tanks are not stabilized, they would fail in the future, causing tank pollutants to enter the environment. DOE needs to decide on the best demonstrated technologies to close the tanks through appropriate evaluation of various alternatives in accordance with the Closure Plan approved by SCDHEC.

2.0 PROPOSED ACTION AND ALTERNATIVES

2.1 Proposed Action

The proposed action is to implement the Closure Plan approved by SCDHEC to remove the contaminants from the tank systems and to fill them with a structural material to prevent future collapse and bind up residual wastes. While the major focus of the closure activities is the HLW Tanks, the tank farms include other equipment for processing the waste, for example, evaporators, diversion boxes, pumps, and inter-area transfer lines which would be closed in a similar manner. Details of these systems are discussed in Appendix A and in the Closure Plan (DOE, 1996). The proposed action begins when bulk waste removal has been completed and the tank system is turned over to the tank closure project. A general protocol for closing the tank systems is outlined in the Closure Plan (DOE, 1996). The major steps in the tank closure project as outlined in the Closure Plan are:

Evaluation and Cleaning Phase:

• Determination of Performance Objectives - Environmental regulatory requirements and guidance would be used to develop closure standards that would be protective of human health and the environment. These would provide the regulatory basis for tank closure methods.

• Cleanup and Stabilization Selection - After waste removal, an evaluation would be conducted against the closure standards to determine the necessary cleaning and stabilization methods to be employed for the tank system closure. Waste generated by cleaning would be recycled through the HLW processing system.

Approval Phase:

• Closure Module Preparation and Approval - A tank system specific Closure Module would be developed that describes the end state of the tank, the performance modeling results, and closure details. The module would be submitted to SCDHEC and Environmental Protection Agency (EPA) for approval.

Stabilization Phase:

• Tank Stabilization - The details presented in the approved tank-specific Closure Module will be executed.

The closed tank system will then be turned over to the SRS Environmental Restoration Program.

To execute the proposed action, several alternatives were explored (all costs are in FY96 dollars).

2.1.1 Bulk Waste Removal, Clean, Fill Tanks With Pumpable Backfill Material (Preferred Alternative)

Evaluation and Cleaning Phase

Each tank or group of tanks, as appropriate, would be evaluated to determine the inventory of contaminants (radiological and nonradiological) present after bulk waste removal which includes spray washing. This information would be used to conduct a performance evaluation. This evaluation would take into account differences in the types of contamination and configurations of cooling coils and equipment, and the hydrogeologic configuration of the tanks, or group of tanks, such as distance from the water table, and distance to nearby streams. The performance evaluation includes modeling the projected contamination pathways for selected closure configurations and comparing the modeling results with the performance objectives developed in the Closure Plan (DOE, 1996). If the performance objectives are met, closure would continue to the stabilization phase.

If the performance objectives cannot be met additional cleaning steps such as additional spray washing, oxalic acid cleaning, or other cleaning techniques of comparable effectiveness would be taken, as required.

• Spray washing--This process involves spray washing each tank using rotary spray jets with hot water. The spray nozzles can remove waste near the edges of the tank that is not readily removed by slurry pumps. After spraying, the contents of the tank would be agitated with slurry pumps and pumped out of the tank. This process has been demonstrated on Tanks 16 and 17. The amount of waste left after spray washing was estimated at about 18,927 liters (3,500 gallons) in Tank 16 and about 15,142 liters (4,000 gallons) in Tank 17 (du Pont, 1980; WSRC, 1995a).

• Oxalic acid cleaning--In this process, after the spray washing is complete, hot oxalic acid would be sprayed through the spray nozzles that were used for spray washing. This process has been demonstrated on Tank 16 only. A number of potential cleaning agents for sludge removal were studied. Oxalic acid was chosen as the preferred cleaning agent because it dissolves sludge, and is only moderately aggressive against carbon steel, the material used in the construction of the waste tanks.

• Annulus cleaning--Nine tanks have leaked measurable amounts of waste from primary containment to secondary containment (WSRC, 1995b). For these tanks, the waste would be removed from the annulus using water and/or steam. Annulus cleaning has been attempted at SRS on only one tank (Tank 16), and the operation was only partially completed. Thus, annulus cleaning is not a demonstrated technology, and new techniques may need to be developed. The amount of waste in secondary containment is small, so the environmental risk of this waste is minimal compared to the amount of waste contained inside the tanks.

Stabilization Phase

After cleaning, each tank, ancillary equipment, tank annulus (if applicable), etc., would be filled with a pumpable, self-leveling backfill material. The fill material would be trucked to an area near the tank farm, batched if necessary, and pumped to the tank to be closed. The fill material would be high enough in pH to be compatible with the carbon steel walls of the waste tank. The fill material would be formulated with chemical properties that would retard the movement of radionuclides from the closed tank. Thus, the closure configuration for each tank, or group of tanks, would be determined case by case. Although the details of each individual closure would vary, any tank system closure under this alternative would have the following characteristics:

• The fill material is pumpable, self-leveling, designed to prevent future subsidence of the tank, and would fill voids to the extent practical, including equipment and secondary containment.

• The fill material would be formulated to reduce the migration of radionuclides.

• The fill configuration discourages inadvertent intrusion.

• The final closure configuration would meet performance objectives established by SCDHEC and EPA.

This alternative would cost approximately $2,500,000 and would result in an estimated 10.2 man-rem of worker exposure per tank system (includes ancillary equipment) closed. A detailed description of this closure alternative can be found in APPENDIX B: Closure Configuration of this EA.

2.1.2 Bulk Waste Removal, Clean, Fill Tanks With Sand

Evaluation and Cleaning Phase

As in the preferred alternative, bulk waste would be removed and the tanks cleaned sufficiently, using the best demonstrated technology, to meet the performance objectives of the Closure Plan (DOE, 1996).

Stabilization Phase

This process is similar to the preferred alternative except sand would be used instead of pumpable, self-leveling materials. The sand would be carried by truck to an area near the tank farm and conveyed to the tank to be closed.

Sand is readily available and inexpensive. However, its emplacement is more difficult than the pumpable, self-leveling material as it does not flow readily into voids. Any equipment/piping left on or inside the tank, that requires filling to eliminate the voids inside the device, would not be sufficiently filled. Over time, the sand would settle in the tank, creating additional void spaces. The dome would then become unsupported and would sag and crack. There would not be the catastrophic collapse as would be anticipated in the no action case. The sand would tend to isolate the contamination from the environment to some extent and prevent winds from spreading the contaminants. However, water would flow readily through the sand. Also, sand is relatively inert and could not be formulated to retard the migration of radionuclides. Thus, the expected contamination levels in groundwater and surface streams, resulting from migration of residual contaminants, would be higher than for the preferred alternative.

This alternative would cost approximately $2,500,000 and would result in an estimated 10.2 man-rem of exposure per tank system closed (DOE, 1996).

2.1.3 Bulk Waste Removal, Clean, Fill Tanks With Saltstone

Evaluation and Cleaning Phase

This alternative would also include bulk waste removal and cleaning to meet the performance objectives of the Closure Plan as discussed in the preferred alternative.

Stabilization Phase

The stabilization process is similar to the preferred alternative except, the fill material used would be saltstone. Saltstone is a low radioactivity fraction of HLW mixed with cement, flyash, and slag to form a concrete-like mixture. Z-Area is currently operating a Saltstone Facility, processing radioactive waste from In-Tank Precipitation (ITP) and Effluent Treatment Facility (ETF) for disposal in Z-Area. This alternative has the advantage of reducing the amount of Saltstone Landfill Area that would be required because any saltstone sent to a waste tank would not require a vault or other disposal technique.

This alternative has several disadvantages:

• The total amount of saltstone to be made to stabilize the low-activity fraction of HLW would probably be greater than 378,541,186 liters (100 million gallons), which is considerably in excess of the capacity of the waste tanks. Saltstone sets up quickly, is radioactive, and would be impractical to ship by truck or pump to the tank farms. Thus, a Saltstone Mixing Facility would need to be constructed in F-Area, another one in H Area, and the existing Saltstone Facility in Z Area would still need to be operated (DOE, 1996).

• Filling the tank with a grout mixture that is contaminated with radionuclides would considerably complicate the project and increase worker radiation exposure, further adding to the expense ($5,000,000 per tank) and risk (DOE, 1996).

2.2 Alternatives to the Proposed Action

In accordance with the NEPA regulations, DOE examined the following alternatives for the proposed action:

• No action; bulk waste removal, no fill material, abandonment

• Clean tanks to the extent allowing removal of tanks

2.2.1 No Action; Bulk Waste Removal, No Fill Material, Abandonment

Under the no-action alternative, the bulk waste would be removed from the existing 51 HLW tanks. The tanks would contain a residual waste and ballast water (as required) and not be filled with backfill material. After some period of time, the reinforcing bar in the roof of the tank would rust, and the roof of the tank would fail, causing the structural integrity of the tanks to degrade. Rainwater would readily pour into the exposed hole, flushing contaminants from the residual waste in the tank and carrying these contaminants into the groundwater.

This alternative would be the least expense (i.e., approximately $56,000 per tank), require the least amount of field work and associated exposure (2 man-rem), and would require 37 fewer workers per tank system. There would be no impact on surrounding tanks and no interruption of ongoing operations in the tank farm. Future inhabitants of the area would be exposed to the contamination in the tank, and injuries or fatalities could occur if an intruder ventured into the area of the tank and the roof were to collapse due to structural failure. Also, movement of the contaminants into the groundwater is most rapid with this alternative, and expected contamination levels in groundwater and surface streams would be higher than for the preferred alternative (see 2.1.1 above) since there would be no containing media (DOE, 1996).

This alternative would not be protective of human health and safety or of the environment.

2.2.2 Clean to Extent Allowing Removal of the Tanks

Evaluation and Cleaning Phase

No evaluation of migration of residual contaminants and consequent impacts would need to be performed as the contaminated portions of the tank would be completely removed from the ground. After waste removal, each sludge or salt tank would undergo additional cleaning beyond that contemplated in other alternatives, perhaps oxalic acid cleaning, mechanical cleaning, and additional steps (yet to be defined) until it is clean enough to be safely removed.

Stabilization Phase

The tank steel components would be cut up, removed, placed in approximately 3,900 B-25 burial boxes (DOE, 1996), and transported to the burial grounds for disposal.

The advantage of this alternative is that there is the potential to dispose of the contaminated tank components in a waste management facility that has better barriers to the migration of contamination than in the current tank farm location.

The disadvantages include:

• High radiation exposure to workers during the removal process ( 93 man-rem per tank versus 10.2 man-rem for the preferred alternative) (DOE, 1996)

• Extremely high cost ($50,000,000 per tank - 20 times more expensive than the preferred alternative) (DOE, 1996)

• Considerable impact on tank farm operations

• Has not been demonstrated on actual HLW tanks

• May need to build additional burial facilities

2.2.3 Other Technologies

Mechanical and chemical cleaning involving advanced techniques have not been demonstrated in actual HLW tanks. A number of techniques have been studied involving such technologies as robotic arms, wet-dry vacuum cleaners, and remote cutters. However, none of these techniques can be considered as viable options at this time. For example, no robotic arms have been demonstrated that could navigate through the forest of cooling coils that are found in most SRS waste tanks. Also, as mentioned previously, there are more aggressive cleaning agents than oxalic acid, (e.g., nitric acid). However, these cleaning agents have an unacceptable environmental risk because they attack the carbon steel wall of the waste tank, causing deterioration of the metal, and reducing the intact containment life of the tank.

Oxalic acid cleaning has been demonstrated to provide cleaning that is at least 10 times as effective as bulk sludge removal alone, and it is relatively compatible with existing waste removal plans and processes, although it generates large quantities of sodium oxalate that requires disposal.

DOE is actively sponsoring research on improved cleaning methods. If improved cleaning methods are developed that provide equal or superior cleaning effectiveness to those discussed in the preferred alternative, these cleaning methods may be substituted. For example, it would be beneficial to develop a cleaning method that does not generate large quantities of sodium oxalate, an additional waste that would require disposal, (as is the case with oxalic acid cleaning).

DOE is also evaluating using contaminated soils (in a soil-cement form) as a fill material.

3.0 AFFECTED ENVIRONMENT

SRS occupies an area of approximately 800 km2 (300 mi2) in southwestern South Carolina (Figure 1-1). The site borders the Savannah River for about 27 km (17 mi) near Augusta, Georgia, and Aiken and Barnwell, South Carolina. SRS contains five nuclear production reactor areas, two chemical separations facilities, waste treatment, storage and disposal facilities, and various supporting facilities. The Final Environmental Impact Statement (EIS) for Waste Management (DOE, 1995a) contains additional information on SRS areas and facilities.

3.1 Land Use

The F- and H-Tank Farms are highly industrialized and have been so since the 1950s when the site was established. The tank farm areas are situated in the north-central portion of SRS, bounded by Upper Three Runs to the north and Fourmile Branch to the south. Land within an eight kilometers (five mile) radius of these areas lies entirely within the SRS boundaries and is used for either industrial purposes or as forested land (DOE, 1994). Figures 1-2 and 1-3 are aerial photographs of the tank farm areas and give an indication of the industrial nature of each location.

For modeling purposes, it is assumed that the SRS separations and environmental management areas (area between Fourmile Branch and Upper Three Runs) would continue to be under institutional control for the next 100 years, and after that the area would be zoned industrial for an indefinite period with deed restrictions on the use of the groundwater (DOE, 1996).

3.2 Regional Demographics

Within an 80 km (50 mi) radius of the center of SRS is a total resident population of approximately 730,000. One major urban center, Augusta, Georgia (1990 population of 44,639) (renamed August-Richmond County in 1995 with a population greater than 150,000), lies about 40 km (25 mi) west-northwest of the site. Four other cities within the 80 km (50 mi) radius had 1990 populations greater than 13,000: Aiken, South Carolina, about 32 km (20 mi) north-northwest; Orangeburg, South Carolina, 77 km (48 mi) east northeast; North Augusta, South Carolina, 37 km (23 mi) northwest; and Evans, Georgia, about 56 km (35 mi) west-northwest of the site. All other cities and towns have populations less than 7,000, the largest being Belvedere, South Carolina, followed by Red Bank, South Carolina, Waynesboro, Georgia, and Barnwell, South Carolina (WSRC, 1995c).

The industrial population, consisting primarily of the SRS work force, Vogtle Electric Generating Plant employees, and employees of 16 smaller industries located in or near Barnwell, Williston, New Ellenton, and Jackson, South Carolina, comprise a daily transient population of approximately 25,734. Most of this total population works Monday through Friday from about 8:00 a.m. to 4:00 p.m. These workers spend an average of about 45 hours per week at the worksite. The industrial population within a eight kilometer (five-mile) radius of F- and H-Areas consists entirely of SRS employees at A/M-, B-, C-, N-, E-, F-, H-, K-, R-. S-, and Z-Areas (WSRC, 1995c).

3.3 Socioeconomics

The workforce to be employed in the tank closure operations would consist of approximately 37 individuals (du Pont, 1982). It is expected that all of this workforce would be composed of existing local workers rather than new workers immigrating into the SRS area. The workforce would consist of a mixture of current SRS employees already working on tank farm related activities or relocated from their present job assignments and construction workers. The Final EIS for Waste Management (DOE, 1995a) and the most recent socioeconomic survey of the six-county SRS area of influence (NUS, 1992) contains additional information on the areas surrounding SRS.

3.4 Meteorology and Climatology

The SRS region has a temperate climate with mild winters and long summers. The average annual rainfall at SRS is about 122 cm (48 in) and the average wind speed in 1987-91 was 13.7 km/h (8.5 mi/h) (WSRC, 1989; DOE, 1995a). Tornadoes have been observed during every month of the year in the area encompassing SRS, but occur most frequently in the spring (WSRC, 1989). Only a few instances of slight to moderate tornado damage to support facilities have been documented for the site to date. The Reactor Operation Environmental Information Document, Volume III: Meteorology, Surface Hydrology, Transport and Impacts (WSRC, 1989) contains additional information on SRS meteorology and climatology. The general meteorological and climatological data for SRS would be representative of that for the F- and H-Tank Farm areas.

3.5 Geology and Seismology

SRS is located in the Aiken Plateau physiographic region of the upper Atlantic Coastal Plain approximately 40 km (25 mi) southeast of the Fall Line which separates the Piedmont Plateau from the Atlantic Coastal Plain. The topographic surface of the coastal plain slopes gently seaward and is underlain by a wedge of seaward-dipping unconsolidated and semiconsolidated sediments from the Fall Line to the coast of South Carolina. Figure 3-1 shows SRS fault locations and a recent EIS (DOE, 1995a) contains additional information on SRS fault location and earthquake occurrences.

The principal surface and near-surface soils in F- and H-Area are clayey sands averaging about one-third clay. These soils have demonstrated a good retention capacity for most radionuclides (Parsons, 1996). The stratigraphic layer which comprises the vadose zone is the Hawthorn Formation or Upland Unit. Extending over much of SRS, this formation contains predominantly red-brown to yellow-orange, coarse to fine sand, and silty clay with localized gravel lenses. The thickness of the Hawthorn Formation ranges from 4.9 m (16 ft) to 12.2 m (40 ft) in the vicinity of the F- and H-Areas Seepage Basins (WSRC, 1991) which are southwest and west of the F- and H-Area Tank Farms, respectively.

A notable feature of the Hawthorn Formation is its compositional variability. Lenses of clay, sand, and sandy clay occur throughout the layer. The unit is traversed by small scale joints and fractures, both of which are commonly filled with sand or silt. The soils at F and H-Area are 20 percent to 40 percent clay. The dominant clay mineral is kaolinite, with small amounts of other clays and weathered mica (WSRC, 1991).

3.6 Hydrology

The Savannah River forms the western boundary of SRS and receives drainage from five major tributaries on the site: Upper Three Runs, Fourmile Branch, Pen Branch, Steel Creek, and Lower Three Runs. These tributaries receive varying types of wastewater discharges from plant processes and sanitary treatment systems, all of which are permitted through the National Pollutant Discharge Elimination System (NPDES). On SRS, various plant processes also require the pumping of Savannah River water and/or on-site groundwater. A recent EIS (DOE, 1995a) contains information on groundwater systems on SRS and in the surrounding region.

The F-Area Tank Farm is on a near-surface groundwater divide between Upper Three Runs and Fourmile Branch. The near-surface groundwater from the southern part of the F-Area Tank Farm discharges to Fourmile Branch, approximately 1,524 m (5,000 ft) to the southwest. The near-surface groundwater from the northern part of the F-Area Tank Farm discharges to Upper Three Runs, approximately 1,372 m (4,500 ft) to the northwest (DOE, 1996).

H-Area is also located on a near-surface groundwater divide between Upper Three Runs and Fourmile Branch. The near-surface groundwater from the northern part of the H-Area Tank Farm discharges to Upper Three Runs, approximately 1,219 m (4,000 ft) to 3,658 m (12,000 f) north to northeast of the tank farm. The near surface groundwater from the southern part of the H-Area Tank Farm discharges to Fourmile Branch, approximately 1,524 m (5,000 ft) to 4,572 m (15,000 ft) southwest of the tank farm (DOE, 1996).

3.7 Ecological and Cultural Resources

Since 1951, when the U.S. Government acquired SRS, natural resource management practices and natural succession outside of the construction and operation areas at SRS have resulted in increased ecological complexity and diversity of the site. Forested areas support a diversity of wildlife habitats that are restricted from public use. Forest management practices include controlled burning, harvesting of mature trees, and reforesting. Wildlife management includes control of SRS white-tailed deer (Odocoileous virginianus) and wild swine (Sus scrofa) populations through supervised hunts. SRS, which was designated as the first National Environmental Research Park in 1972, is one of the most extensively-studied environments in this country. Wike et al. (1994) contains additional information on the biotic characteristics of SRS.

Six species on SRS are afforded protection by the Federal government under the Endangered Species Act of 1973. They are the bald eagle (Haliaeetus leucocephalus), wood stork (Mycteria americana), red-cockaded woodpecker (Picoides borealis), American alligator (Alligator mississippiensis), shortnose sturgeon (Acipenser brevirostrum), and smooth purple coneflower (Echinacea laevigata).

Due to the industrial nature of the tank farms, the activities and the plants or animals mentioned do not exist within the boundaries of the fenced portion where the activities associated with the closure of the tanks would take place.

A Memorandum of Agreement (MOA), ratified on August 24, 1990, exists for the management of cultural resources at SRS. DOE uses this (MOA) to identify cultural resources, assess them in terms of eligibility for the National Register of Historic Places, and develop mitigation plans for affected resources in consultation with the State Historic Preservation Officer (DOE, 1996).

Studies of F- and H-Areas in a previous EIS (DOE, 1994) noted that activities associated with the construction of F- and H-Areas during the 1950s could have destroyed historic and archaeological resources present in this area. If any historic or archaeological resources are threatened by HLW tanks closure activities under this plan, appropriate steps would be taken to identify the resource found and to contact the appropriate agency in accordance with the MOA (DOE, 1996).

3.8 Radiation Environment

A person residing in the Central Savannah River Area (within 80 km (50 mi) of SRS) receives an average annual radiation dose of about 360 mrem. Natural radiation sources contribute about 295 mrem, medical exposures contribute about 53 mrem, and consumer products contribute about 10 mrem. SRS contributes 0.23 mrem (less than 0.1 percent of that total). The most recent SRS annual environmental report (Arnett et al., 1995) contains more information on the radiation environment at SRS.

4.0 ENVIRONMENTAL CONSEQUENCES OF THE PROPOSED ACTION AND ALTERNATIVES

4.1 Tank System Closure

For all closure alternatives, direct and indirect socioeconomic impacts of the proposed tank closure construction workforce would be negligible when compared to the present total SRS employment of approximately 14,000 people. All of the construction workforce would likely be derived from the existing ranks of local construction companies. Therefore, no measurable impact on the local economy would be expected from the proposed action. Because no socioeconomic impacts are expected as a result of the proposed action, no disproportionate impacts on minority or low income communities would result.

The construction activities for each of the closure alternatives may include, as applicable, the removal of pipes, equipment, electrical conduit and wires, lead loosely wrapped around pipes for shielding, evaporators, and other miscellaneous parts necessary to complete the closure process. It is estimated that approximately 85 m3 (3,000 ft3) of equipment above the ground surface could be removed, placed in B-25 (radioactive waste storage container) boxes or equivalent, and transported to the E-Area vaults for long term disposal. A B-25 box holds approximately 2.55 m3 (90 ft3) of material. It can be assumed that a box would contain 1/5 of 2.55 m3 (90 ft3) of the cut up equipment which could result in as many as 167 B-25 boxes per tank if all the surface equipment were removed (DOE, 1996; Hall, 1996).

For closure alternatives involving fill, other construction activities would include the installation of the transfer pipes to be used in pumping the fill mixture to the tanks. The piping would be changed and rerouted to other tanks as each tank is filled.

The construction workers would receive some radiation exposure during the removal process and while stabilizing the tanks with fill. All workers would wear proper personnel protective equipment as specified by the radiation control program and would maintain their radiation exposure as low as reasonably achievable. Exposure levels to workers could be expected to be on the order of 10 to 11 man-rem per tank averaged over 37 workers, or about 0.3 rem per worker per year. This was derived by breaking the tank closure down into four parts and adding the total exposures together. The first phase is the removal of the surface structure which incorporates ten workers for twelve weeks in a one mrem/hr field that equals 4800 mrem. This equates to 4.8 man rem. The second phase is installing a portable pumping station and running the piping to the tanks which utilizes five workers for twelve weeks in a 0.5 mrem/hr field. This equates to 1.2 man rem. The third phase is the filling of the tanks with the backfill material utilizing eleven workers for 20 weeks in a 0.5 mrem/hr field. This equates to 4.4 man rem. The final phase, if required, is installing the cap on the tanks which employs eleven workers for four weeks in a 0.1 mrem/hr field which equates to 0.2 man rem (Hall, 1996). This estimated exposure of about 0.3 rem per worker per year is less than the current SRS administrative limit of 0.8 rem per year.

Since the area of the proposed action has been within a developed industrialized area for the last 50 years, no adverse impacts to known cultural or biotic (e.g., threatened and endangered species) resources would be expected to result from the construction activities. Neither wetlands nor floodplains exist within or adjacent to the project area.

Air quality effects associated with the tank closure activities would fall within two areas: equipment use and soil disturbance. Diesel operated equipment (i.e., trucks, backhoes, and other diesel powered support equipment) would be used for material to fill the tanks, to haul soil and other debris for disposal, for excavation, capping activities, if required, and in the performance of other routine construction activities. The operation of this type of equipment does not require an air quality permit from SCDHEC. If a batch plant were used on site to mix fill material, some fugitive dust would be produced.

4.2 Post-Tank Closure

When the F- and H-Tanks are closed, there will be minimal active operational and maintenance activities in the area. The major impacts anticipated during post-tank closure would be the release of contamination from the closed tanks due to deterioration of the tanks in future years. This contamination is expected to migrate, over a period of several thousand years, into the groundwater and eventually, via the seepline, to Upper Three Runs and Fourmile Branch. By the time the contamination reaches the seepline (which is defined as the point of compliance in the Closure Plan) of the creeks, the contamination levels would fall within the acceptable stream standard limits. A detailed discussion of the tank closure performance evaluation and performance objectives are presented in the Closure Plan (DOE, 1996).

4.3 Human Health Effects

The accident analyses and fate and transport modeling (DOE, 1996) indicate that after closure, there are no airborne releases that would result in any human health effects. As the HLW tanks are underground, runoff or surface soil contamination is not expected.

The contaminated zone would be encountered below the surrounding, original land surface, therefore, groundwater is where the contamination is anticipated to occur. Human receptors will potentially be exposed to contaminants through various pathways associated with the surface water adjacent to the seepline where the contaminated groundwater reaches the surface.

As an example of the impacts that might occur, fate and transport modeling, using various post-closure tank configurations, was performed using Tanks 17 through 20 in the F-Area Tank Farm (DOE, 1996). The specific closure scenarios modeled were: (1) bulk waste removal and spray wash, no fill material (no action), (2) bulk waste removal and spray wash, fill tanks with pumpable backfill material, (3) bulk waste removal and spray wash, fill tanks with pumpable backfill material, place an engineered cap over filled tanks, and (4) bulk waste removal and spray wash, fill tanks with sand, and place an engineered cap over filled tanks.

The modeling assumed institutional control for 100 years and subsequent industrial land use. The area immediately around the F-Area Tank Farm would remain in commercial/industrial use for the entire 10,000-year period of analysis. The area of commercial/industrial land use would extend to Fourmile Branch in the direction of groundwater flow in the unconfined aquifer. The modeling estimated the potential human health and ecological impacts of residual contamination remaining in closed HLW tanks. The modeling also estimated the concentration and dose levels at the groundwater seepline, which is the established point of compliance.

Radiological doses at the seepline (the point of compliance) were calculated to be as high as 5 mrem/year (Scenario 1 - No Action) and as low as 3.4 mrem/year (Scenario 3 Backfilled with Cap). The acceptable limit is 4.0 mrem per year. Essentially all of this dose is due to selenium-79 and technetium (Tc-99) because the other radionuclides either decay en route or do not migrate at a sufficient rate to reach the seepline. The calculated gross alpha concentration at the seepline demonstrates that appreciable amounts of plutonium 239 do not arrive at the seepline within the 10,000 year period of analysis, regardless of the analyzed scenario. The lifetime risk of incidence of excess cancer for the most affected human receptor was calculated to be in the order of 1.8E-07 or less for all scenarios.

For nonradiological constituents a full tank was used for the analysis. Nitrate is the only contaminant to reach the seepline in quantities that could exceed the maximum contaminant level. After bulk waste removal plus spray washing, values would be lowered to a point where maximum contaminant levels would not be exceeded (DOE, 1996).

The modeling shows that maximum doses and concentrations of contaminants do not vary dramatically between closure alternatives (usually by less than an order of magnitude). The primary difference is in the arrival time of the maximum dose/concentration at the seepline several thousand years after closure.

For any tank closure module, SCDHEC limits would not be exceeded at the seepline of Fourmile Branch and Upper Three Runs, thus significant human health effects are not expected from surface water contamination from the proposed action.

4.4 Transportation Impact Analysis

SRS is served by more than 320 km (199 mi) of primary roads and more than 1600 km (995 mi) of unpaved secondary roads. The primary highways used by SRS commuters are State Routes 19, 64, and 125; 40, 10, and 50 percent of the workers use these routes respectively. Significant congestion can occur during peak traffic periods onsite on SRS Road 1-A, State Routes 19 and 125, and U.S. Route 278 at SRS access points. These same routes and access points would be used by construction vehicles associated with this action.

Action to fill any tank would require materials such as sand, cement, flyash, and blast furnace slag to be transported to the site to make the fill material. The trucks could come to the site with premixed fill material batched at the vendor's facility. Approximately 800 to 900 truck loads of material would be required to fill each waste tank (DOE, 1996). This would require 800 to 900 round trips from an offsite vendor's facility for each tank or a total of approximately 45,900 round trips. Assuming that the material is supplied by vendor facilities in Jackson and New Ellenton, closure of the tanks would result in approximately 2.3 million miles traveled during the waste tank closure process. Using U. S. Department of Transportation national average accident rate data for fatalities and injuries (DOT, 1982), the proposed transportation activity would result in 0.01 additional fatalities and 0.79 additional injuries.

The transportation impacts for tank removal would be less than any fill alternative as only 780 truck loads are required and all movement would be on site.

Regardless of alternative chosen, it is anticipated that one tank would be closed at a time, thus, the existing transportation structure would be adequate to accommodate this projected traffic volume. None of the routes associated with this transportation would require additional traffic controls and/or highway modifications. The surrounding area already has a certain volume of truck and car traffic associated with SRS logging, agriculture, and industrial activity. The amount of traffic associated with the proposed action is minimal.

4.5 Accident Impact Analysis

To assess the impact of accidents associated with the proposed action, it was necessary to perform a comparative analysis of pre-closure HLW tank operations and post-closure conditions. This analysis, provided in Appendix C: Comparative Analyses of Pre-closure HLW Tank Operations and Post Cloure Conditions, examined the most severe potential accidents associated with the HLW tank farm operations and determined the impact those same accidents would have on the waste tanks after closure.

None of the 13 design basis accidents for current tank farm operation involves a significant airborne release of radioactive material. Only the tornado scenario would result in a release of vapors from a waste tank under current operating conditions. After closure of the waste tanks, there would be no vapor space in the tanks and, thus, no vapors present in the waste tanks, and no unsealed waste tank penetrations. Therefore, a tornado would not result in any release from the closed waste tanks. Based on this review of the current accident analyses, there are no credible accident airborne release mechanisms for the HLW tanks after tank closure.

4.6 Environmental Consequences of the Alternatives

No direct environmental impacts are expected as the proposed action will take place within a previously-developed industrial area. However, the near surface groundwater (measured at 1-meter and 100-meters down gradient from the tank farms) is expected to become contaminated such that it will not meet SCDHEC standards. This is not expected to occur until several hundred years after tank closure when the tank, grout, and basemat are anticipated to fail due to deterioration, as indicated by the fate and transport modeling performed for the Closure Plan (DOE, 1996).

The mobile contaminants in the tanks will gradually migrate downward through the soil to the groundwater aquifer. The contaminants will be transported by the groundwater to the seepline and subsequently to either Fourmile Branch or Upper Three Runs. As indicated by the fate and transport modeling (DOE, 1996), the contaminants in the groundwater are expected to be reduced, such that, by the time they reach the seepline of the creeks they would be within the acceptable limits. Upon reaching the surface water, some contaminants will possibly contaminate the seepline, sediments at the bottom of Fourmile Branch and Upper Three Runs, and the shoreline, but would be at levels below regulatory concerns. Aquatic organisms in the stream and plants along the shoreline will become exposed to the contaminants. Terrestrial organisms may then ingest the contaminated vegetation and also obtain their drinking water from the contaminated stream.

4.7 Cumulative Impacts

There would be no measurable increase in the local economy as a result of the proposed action and thus no cumulative impacts are anticipated.

The site usage of domestic and potable water would be increased by less than one percent. The volume of sanitary wastewater treated at the Central Treatment Facility would increase by less than one percent.

The cumulative impact on the site streams are caused by the combination of this action's HLW contaminants and the other contaminant plumes which eventually enter Upper Three Runs to the west of the tank farms and Fourmile Branch to the south. Groundwater transport segments (GTS) will be defined for the tanks to be closed to apportion the performance objectives to the target tank system(s) and other sources of contaminants that may impact the same point of exposure. A GTS represents the adjacent contaminant plume from the tank system(s) considered for closure and all other sources within the segment. In general, a GTS will run from the groundwater divide to the point of exposure. The performance objectives established in the Closure Plan (DOE, 1996) limit these to acceptable levels.

Currently, construction activities on site are winding down and workforce restructuring is decreasing the amount of vehicle traffic associated with activities at the site. However, increased truck traffic would be caused by the construction and operation of the Three Rivers Solid Waste Authority Regional Waste Management Center discussed in Environmental Assessment DOE/EA-1079 (DOE, 1995b). This tank closure action only adds 10 to 40 trucks per day.

5.0 REGULATORY AND PERMITTING PROVISION CONSIDERATIONS

5.1 National Environmental Policy Act of 1969, as Amended (42 USC 4321 et seq.)

This EA has been prepared in compliance with the NEPA of 1969, as amended, and the Council on Environmental Quality Regulations for Implementing NEPA (40 CFR Parts 1500-1508), DOE Regulations (10 CFR Part 1021), and DOE Order 451.1. NEPA, as amended, requires "all agencies of the Federal Government" to prepare a detailed statement on the potential environment effects of proposed "major Federal actions significantly affecting the quality of the human environment." This EA has been prepared to comply with NEPA and to assess the significance of the environmental effects of closing the 51 HLW storage tanks in F- and H-Areas.

5.2 Federal Facility Agreement (FFA)

An FFA (DOE, EPA, and SCDHEC, 1993) was executed by DOE, EPA, and SCDHEC, and became effective on August 16, 1993. The FFA provides standards for secondary containment, requirements for responding to leaks, and provisions for the removal from service of leaking or unsuitable HLW storage tanks. Tanks that do not meet the standards set by the FFA may be used for the continued storage of their current waste inventories, but these tanks are required to be placed on a schedule for removal from service. The "F/H Area High-Level Waste Removal Plan and Schedule," submitted to EPA and SCDHEC on November 10, 1993, shows specific start and end dates for the removal from service of each non-compliant tank, and commits SRS to remove the last non-compliant tank from service no later than 2028.

The FFA requires that the tanks be closed under the requirements of the Pollution Control Act via the tank farm industrial wastewater permits. Subsequent to wastewater closure, the FFA requires an additional evaluation under the RCRA/CERCLA sections of the agreement. However, after negotiations between the three parties, the FFA may be modified to reflect an integrated approach to tank systems closure.

5.3 Industrial Wastewater

The FFA (DOE, EPA, and SCDHEC, 1993) directed SRS to submit an industrial wastewater permit application to SCDHEC. Upon issuance of the permit to operate on March 3, 1993, SRS requested the withdrawal of the tank farms from the Site RCRA Part A permit application. The tank farms currently operate under Industrial Wastewater Permit to Operate #17-424-1W, #14338, and #14502. This permit allows for the continued operation of the tank farms as described in Appendix A. The permit regulates the removal of waste from all 51 HLW tanks as well as the pretreatment of the waste in the ESP and ITP facilities. SRS is driven to empty these tanks through the FFA via the wastewater permit. After removal of non-compliant tanks from service, the tanks will be closed as described in the Closure Plan (DOE, 1996).

5.4 Additional Regulatory And Permitting Provisions

DOE has identified all applicable or relevant and appropriate environmental requirements and guidance it will comply with and consider, respectively, to insure that the tank system closures will be protective of human health and the environment and are consistent with final corrective/remedial action as implemented under the FAA. Details of these can be found in Chapter 5 of the Closure Plan (DOE, 1996).

6.0 REFERENCES

Arnett, M. W., D. Spitzer, and A. R. Mamatey, 1995. Savannah River Site Environmental Report for 1994, WSRC-TR-95-075, Westinghouse Savannah River Company, Savannah River Site, Aiken, South Carolina.

DOE (Department of Energy), 1982. Environmental Assessment, Waste Form Selection For SRP High-Level Waste, DOE/EA-00179, Savannah River Site, Aiken, South Carolina.

DOE (Department of Energy), 1994. Final Supplemental Environmental Impact Statement, Defense Waste Processing Facility. DOE/EIS 0082-S, Savannah River Operations Office, Savannah River Site, Aiken, South Carolina.

DOE (Department of Energy), 1995a. Final Environmental Impact Statement Waste Management, DOE/EIS-0217, 1995, Savannah River Site, Aiken, South Carolina.

DOE (Department of Energy), 1995b. Environmental Assessment, Construction and Operation of the Three Rivers Solid Waste Authority Regional Waste Management Center, DOE/EA-1079, Savannah River Site, Aiken, South Carolina.

DOE (Department of Energy), 1996. Industrial Wastewater Closure Plan for F and H-Area High-Level Waste Tanks, Preliminary Draft, May 15, 1996, Savannah River Operations Office, Savannah River Site, Aiken, South Carolina.

DOE, EPA, and SCDHEC (Department of Energy, Environmental Protection Agency, and South Carolina Department of Health and Environmental Control), 1993. Federal Facility Agreement for the Savannah River Site, Administrative Docket No. 89-05-FF, signed January 15, 1993, effective August 16, 1993, Department of Energy, Savannah River Operations Office, Aiken, South Carolina.

DOT (Department of Transportation), 1982. Large Truck Accident Causation, DOT HS-806300, National Highway Traffic Safety Administration, Washington, DC.

du Pont (E.I. du Pont de Nemours and Company, Inc.), 1980. Tank 16 Demonstration, Water Wash and Chemical Cleaning Results, DPSP 80 17-23, Savannah River Site, Aiken, South Carolina.

du Pont (E.I. du Pont de Nemours and Company, Inc.), 1982. Decommissioning Alternative for Waste Tank 16, DPST-82-456, Savannah River Laboratory, Aiken, South Carolina.

Hall, S. M., 1996. Interoffice Memorandum to M. L. Hess, Info Requested For HLW EA, HLW-HLE-96-0225, May 1, 1996, Westinghouse Savannah River Company, Aiken, South Carolina.

NUS (Halliburton NUS Environmental Corporation), 1992. Socioeconomic Characteristics of Selected Counties and Communities Adjacent to the Savannah River Site, Halliburton NUS Corporation, Aiken, South Carolina.

Parsons, A. M.and M. M Gruebel, 1996. Hydrogeology of the F-Area at the Savannah River Site, Rev. 0, Sandia National Laboratories, Albuquerque, New Mexico.

SCDHEC (South Carolina Department of Health and Environmental Control), 1993. Construction Permit #17,424-IW, "SRS F/H-Area", 25 January 1993, transmitted by Marion F. Sadler, Jr.

Wike, L. D., R. W. Shipley, A. L. Bryan, Jr., J. A. Bowers, C. L. Cummins, B. R. del Carmen, G. P. Friday, J. E. Irwin, J. J. Mayer, E. A. Nelson, M. H. Paller, V. A. Rogers, W. L. Specht, and E. W. Wilde, 1994. SRS Ecology: Environmental Information Document, WSRC-TR-93-496, Westinghouse Savannah River Company, Savannah River Site, Aiken, South Carolina.

WSRC (Westinghouse Savannah River Company), 1989. Reactor Operation Environmental Information Document. Volume III: Meteorology, Surface Hydrology, Transport and Impacts (U), WSRC-RP-89-817, Westinghouse Savannah River Company, Aiken, South Carolina.

WSRC (Westinghouse Savannah River Company), 1991. Baseline Risk Assessment For The F- and H-Area Seepage Basins Groundwater Unit, Draft Final, WSRC-RP-91-950, Westinghouse Savannah River Company, Aiken, South Carolina.

WSRC (Westinghouse Savannah River Company), 1995a. High Level Waste Engineering Monthly Data Report (U), WSRC-RP-95-841-7, Westinghouse Savannah River Company, Aiken, South Carolina.

WSRC (Westinghouse Savannah River Company), 1995b. Annual Radioactive Waste Tank Inspection Program - 1994 (U), WSRC-TR-95-166, Westinghouse Savannah River Company, Aiken, South Carolina.

WSRC (Westinghouse Savannah River Company), 1995c. Safety Analysis Report Savannah River Site, WSRC-SA-19, Rev. 0, Westinghouse Savannah River Company, Aiken, South Carolina.

Appendix A
High Level Waste System Description

The F- and H-Area High Level Waste (HLW) Tank Farms are located in the central portion of the Savannah River Site (SRS). The tank farm sites were chosen because of their favorable terrain, close proximity to the F and H-Area Separations Facilities (the major waste generating sources), and large isolation distance (minimum distance is approximately 8.9 km, 5.5 mi) from the SRS boundaries.

The F-Area HLW Tank Farm is located on a 9 ha (22-acre) site and consists of 22 waste tanks, two evaporator systems, transfer pipelines, six diversion boxes, and three pump pits.

The H-Area HLW Tank Farm is located on a 18 ha (45-acre) site and consists of 29 waste tanks, two evaporator systems, the In-Tank Precipitation (ITP) process building and associated equipment, transfer pipelines, eight diversion boxes, and ten pump pits.

As depicted in Figure A-1, the F- and H-Area HLW Tank Farms were constructed to:

• Receive radioactive wastewaters generated by the various SRS production, process, and laboratory facilities

• Isolate the radioactive wastes from the environment, plant workers, and general public

• Allow radioactive decay by aging the wastewater

• Provide wastewater clarification by gravity settling in waste tanks

• Remove soluble salts from the wastewater by evaporation and/or ion exchange

• Pretreat the accumulated sludge and salt solutions to allow management of these wastes at other wastewater treatment facilities (i.e., Defence Waste Processing Facility (DWPF) and Z Area Saltstone Manufacturing and Disposal Facility) for conversion to more stable forms and placement in permanent disposal facilities

To accomplish the above objectives, the tank farms contain 51 large underground waste tanks to receive and age the waste streams, four evaporator systems (Two are currently operational and a fifth evaporator system is currently under construction) to remove soluble salts, a precipitation/filtration system (i.e., ITP facility) to pretreat the salt solutions, a sludge washing system (i.e., Extended Sludge Processing) to pretreat the accumulated sludge, and a transfer system to transfer the wastes.

All of the tanks were built of carbon steel inside reinforced concrete containment vaults, but were built with four different designs. Two designs (Types I and II,) have five foot high secondary annulus "pans" and forced cooling. There were twelve Type I Tanks (Figure A-2) built (Tanks 1 - 12) between 1951 and 1954. Five tanks (Tanks 1, 9 - 12) have leaked detectable amounts of waste from primary to secondary containment. The tank tops are about 2.9 m (9.5 ft) below grade. The bottoms of the tanks are situated above the seasonal high water table. Tanks 9 - 12 are located in the H Area Tank Farm and are in the water table.

There were four Type II Tanks (Tanks 13 - 16) (Figure A-3) built between 1961 and 1964 and are all located in the H-Area Tank Farm. All four have leaked detectable amounts of waste from primary to secondary containment. On one tank, Tank 16, a small amount of waste overflowed the annulus pan and leaked into the surrounding soil. Waste removal from the Tank 16 primary vessel was completed in 1980. The waste that leaked into the annulus has not been removed. These tanks are situated above the seasonal high water table.

The newest design, Type III (Figure A-4), has a full-height secondary tank and forced water cooling. All of the Type III Tanks (Tanks 25 - 51) were situated above the water table. These tanks were placed in service between 1972 and 1981. None of these tanks have known leak sites.

The fourth design, Type IV (Figure A-5), has a single steel wall and does not have forced cooling. There were eight Type IV Tanks (Tanks 17 - 24) built between 1958 and 1962. Tanks 17 - 20 are located in the F-Area Tank Farm and Tanks 21 - 24 are located in H Area. Tanks 19 and 20 have known leak sites that are believed to have been caused by groundwater corrosion of the tank wall. Small amounts of groundwater have leaked into these tanks; there is no evidence that waste has leaked out. Tanks 17 - 20 are slightly above the water table. Tanks 21 - 24 are above the groundwater table. However, they are in a perched water table caused by the original basemat under the tank area.

The influent wastewaters are classified as high-level radioactive wastes (HLWs). HLWs are produced during the reprocessing of spent nuclear fuel or are derived from other processes which handle HLWs. The HLWs emit harmful levels of radiation and must be isolated to prevent employee exposure to radiation; therefore, direct inspection maintenance of process equipment is not normally conducted. The process equipment is shielded with lead, soil, concrete or steel. Maintenance is normally conducted remotely to prevent exposure of personnel to radiation sources. Should hands-on maintenance be required, the piece of process equipment must be isolated from sources and decontaminated.

The waste treatment activities conducted at the F- and H-Area HLW Tank Farms are "closed-loop" processes which do not have any direct aqueous discharges to the environment. All of the effluent waste streams produced by the tank farms are transferred to other SRS facilities for further treatment. The treatment activities conducted at the F and H-Area HLW Tank Farms are briefly described below.

Waste Receipt and Aging

The freshly generated HLW is further classified as either High-Heat Waste (HHW) or Low-Heat Waste (LHW). HHW is generated during the first solvent extraction of the spent nuclear fuel. LHW is generated from the second and subsequent solvent extractions of the spent nuclear fuel and other support. The freshly generated HHW and LHW are segregated to improve processing of the residual sludge and salt solutions within the Tank Farms and DWPF Vitrification Facility.

HHW contains most of the radionuclides and must be aged in a receipt tank to permit radioactive decay of the short-lived radioisotopes (i.e., half-life is less than 90 days) prior to further processing. The thermal energy resulting from radioactive decay of these short lived radioisotopes requires supplemental cooling (i.e., cooling coils) to maintain the temperature of the HHW receipt tank within operating guidelines. When the radioactivity of HHW in the receipt tank has decayed sufficiently, the liquid supernate is decanted and transferred to a HHW evaporator feed tank for subsequent removal of the dissolved solids through evaporation.

The freshly generated LHW contains a lower concentration of radionuclides; as a result, the LHW normally does not require aging and supplemental cooling prior to evaporation. This LHW is normally received directly in a LHW evaporator feed tank for subsequent removal of the dissolved solids through evaporation of the liquids.

Waste Evaporation

HHW and LHW supernates are transferred from the evaporator feed tanks and heated to the aqueous boiling point in an evaporator. HHW and LHW are normally processed through segregated evaporator systems. The evaporated liquids (overheads) are condensed and, if required, processed through an ion exchange column for cesium removal. The overheads are then transferred to the F/H Effluent Treatment Facility for final treatment prior to being discharged to Upper Three Runs. The evaporator overheads may also be recycled back to a waste tank should evaporator process upsets occur.

Salt Cake Processing

HHW and LHW waste streams contain dissolved salts which are removed through evaporation of the liquids. The concentrated wastes from the evaporators (evaporator bottoms) are sent to a waste concentrate receipt tank with supplemental cooling. Supplemental cooling is required for the evaporator bottoms to remove the heat which is added during evaporation. As the hot concentrated waste cools, a solid salt cake forms and is deposited within the waste concentrate receipt tank. The supernate remaining in the waste concentrate receipt tank is returned to an evaporator feed tank for further processing. Over time, the waste concentrate receipt tank fills with salt cake. Aging of this salt is also required since the radionuclides are concentrated by the evaporation process.

Starting in 1981, HHW and LHW evaporator bottoms have been segregated into separate waste concentrate receipt tanks. Prior to 1981, HHW and LHW evaporator bottoms were combined in the same waste concentrate receipt tank. The combined HHW/LHW salt cakes are managed as a HHW salt cake.

HHW and LHW salt cakes undergo another aging period of several years before radioactive/chemical decontamination may proceed. The aged HHW and LHW salt cakes are dissolved and transferred in batches to the ITP reaction vessel. The dissolved HHW and LHW salt cakes (called salt solution) are combined with each other to achieve blending of the radionuclides and other chemical compounds. This blending is performed to provide more consistent waste feed to the ITP process and subsequent waste feed to the Z Area Saltstone Manufacturing and Disposal Facility (SMDF) and DWPF Vitrification Facility. The combined salt solution is treated with chemical compounds to precipitate and adsorb a majority of the radionuclides. The resulting slurry is filtered within the ITP filter building. The filtrate (called decontaminated salt solution) is transferred to Tank 50. The decontaminated salt solution is combined with the concentrate reject from the F/H ETF and transferred to the Z-Area SMDF for solidification and on-site disposal. The remaining precipitate slurry undergoes a washing step to remove residual soluble salts and process chemicals prior to being transferred to the DWPF Vitrification Facility for vitrification into a solid glass matrix for disposal.

Sludge Processing

The HHW and LHW waste streams generated by the F- and H-Area Separations Facilities contain insoluble and highly radioactive metal hydroxides (manganese, iron, and aluminum) which settle to the bottom of the waste tanks to form a sludge layer. The HHW and LHW are normally segregated. The combined sludge is managed as HHW sludge. In addition to the fresh waste receipt aging, the accumulated HHW and LHW sludge are aged to allow radioactive decay. The aged sludge are transferred to the sludge processing tanks for washing and, if necessary, aluminum dissolution. The HHW and LHW sludge are also combined with each other to provide a consistent effluent waste stream. The washed sludge slurry is transferred to the DWPF Vitrification Facility for vitrification into a solid glass matrix for disposal.

Waste Transfer

A network of transfer lines is used to transfer wastes between the waste tanks, process units, and the various SRS areas (i.e., F-Area, H-Area, and S-Area). These transfer lines have diversion boxes containing removable pipe segments (called jumpers) to complete the desired transfer route. Various sized and shaped jumpers can be fabricated and installed to allow the transfer route to be changed. The use of diversion boxes and jumpers allow flexibility in the movement of wastes.

The waste flows through the evaporator systems and ITP process building are designed to be conducted on a continuous basis. All other wastes are normally transferred in batches. Transfer of waste from any waste tank to any other waste tank, process unit, or treatment facility is possible with the proper arrangement of pumps, transfer lines, and valves. Administrative procedures are established and followed to ensure that the transfer of wastes is conducted safely and properly.

Waste Removal Program

The primary objective of the HLW System is shifting from waste storage to removal of radioactive waste from the older style tanks to prepare the waste, including liquid, salt, and sludge, for feed to DWPF. The waste removal program includes removal of salt and sludge by hydraulic slurrying, cleaning the tank interior by spray washing of the floor and walls, and steam/water cleaning of the tank annulus if necessary. The waste processing program includes decontamination of the salt and liquid for incorporation into saltstone and aluminum dissolution and washing of the sludge for feed to DWPF.

The schedules for waste removal and waste processing are closely linked to each other and with the DWPF schedule. The scheduling objective is to remove the waste from the Types I, II, and IV tanks as rapidly as possible without exceeding the capacity of the tank farm processes or DWPF.

Processes and equipment for waste removal and waste processing have been developed and demonstrated in several successful full-scale radioactive demonstrations. Sludge removal by hydraulic slurrying and chemical cleaning with oxalic acid has been demonstrated in Tank 16. Salt removal and sludge removal using mechanical agitation has also been demonstrated on Tanks 15, 17-22, and 24. Facilities have been designed using data and experience gained from these demonstrations. To date, 2.3 million gallons of salt and 1.1 million gallons of sludge have been removed from Types I, II, and IV tanks.

The Waste Removal Program is a series of projects that install waste removal equipment on the existing waste tanks. The objective of the Waste Removal Program is to remove the waste contained in the tank primary vessel so that the tank can be reused or retired. In general, the Type III tanks will be reused while the Type I, II and IV tanks will be retired when all waste has been removed. The tanks to be retired will also undergo a water washing operation in the primary vessel and an annulus cleaning operation in the annulus if the annulus is contaminated.

Waste removal equipment consists of slurry pump support structures above the tank top, slurry pumps (typically three for salt tanks and four for sludge tanks), bearing water and electrical service to the slurry pumps, motor and instrument controls, tank sampling equipment, tank interior water washing piping and spray nozzles, pressurized wash water supply skids, and heating and ventilation (H&V) skids to augment the existing tank H&V during spray washing.

On salt tanks, the slurry pump discharges are positioned just above the saltcake level. Water is added to the tank, the slurry pumps are started and salt is dissolved. The dissolution ratio is typically 2 parts water to 1 part saltcake although this can vary up to 4 parts water per 1 part saltcake. The slurry pumps serve to displace the boundary layer of saturated water in contact with the saltcake and expose the underlying salt to unsaturated water. When the water is fully saturated, the dissolved salt solution is transferred to ITP, the slurry pumps are lowered and the process is repeated.

On sludge tanks, the four slurry pumps are typically positioned in the top layer of sludge, water is added, and the pumps are started. When the layer of sludge is well mixed (i.e. the sludge is suspended) as indicated by sampling, the transfer pump is started and the suspended sludge is transferred to Extended Sludge Processing (ESP). Note that the slurry pumps continue to operate during the transfer so that the suspended sludge does not resettle. The pumps are then lowered, more water is added, and the process is repeated. Sludge tanks require more pumps than salt tanks because the sludge must be agitated vigorously to suspend the sludge particles as opposed to dissolving saltcake.

For tanks that contain mixed salt and sludge, the salt will be removed followed by the sludge. The process is similar to salt removal described above except that the sludge is allowed to resettle before the saturated salt solution is transferred out of the tank.

When the salt or sludge contents have been removed from the old-style tanks, the tank interior is washed with heated water. The water is sprayed throughout the tank using rotary spray jets installed through the tank risers. The water is supplied to the jets by a skid mounted tank and pump system. For those tanks with contaminated annuli, recirculating jets are installed in the annulus through annulus risers and heated water is circulated in the annulus and then transferred to the waste tank primary. At the completion of water washing, there may be some residual waste that cannot be removed with water. Oxalic acid cleaning has been demonstrated in Tank 16 as a viable process to remove the residual waste. However, oxalic acid cleaning is more expensive and, therefore, it will only be considered on a case by case basis depending on the performance evaluation for each tank.

Two new demonstrations will be conducted in FY96-97 to determine if salt removal can be accomplished using less expensive equipment. High pressure water jets will be used in Tank 25 and a process called density gradient will be demonstrated in Tank 41.

Appendix B
Closure Configuration

An example of an anticipated closure configuration is described. Note, equipment inside and near the tank might remain in place and several tanks may be capped together.

Tank Closure

The various layers of material that would exist in a typical tank closure, starting with the bottom layer of the tank and working upward toward the top, would include the residual waste, reducing grout, Controlled Low-Strength Material (CLSM), and strong grout as described below and shown in Figure B-1:

• The residual waste at the bottom of the tank is the waste that could not be removed by waste removal.

• Reducing grout is a grout mixture composed of primarily cement, flyash, and blast furnace slag. The chemical properties of liquid that leaches through this grout will reduce the mobility of certain radionuclides. The formulation of the backfill material for each waste tank may be adjusted based on specific circumstances for each tank. The material is pumped into the waste tank through an available opening.

• CLSM is Controlled Low-Strength Material, a self-leveling concrete composed of sand and cement formers. Similar to the grout, it is pumped into the tank. The compressive strength of the material is limited by using a limited amount of cement in the mixture. The advantages of using CLSM rather than ordinary concrete or grout for most of the fill are:

- The compressive strength of the material can be controlled so that it will provide adequate strength for the overbearing strata and yet could be potentially excavated with conventional excavation equipment. Although excavation of the tank is not planned, filling the tank with low-strength material would enhance the opportunity for future removal of tank contaminants or, perhaps, the tank itself, if future generations were to decide that excavation is desirable.

- CLSM has a low heat of hydration, which allows large pours. The heat of hydration in ordinary grout limits the rate at which the material can be placed, because the high temperatures generated by thick pours prevent proper curing of the grout. Thus, large pours of grout are usually made in layers, allowing the grout from each layer to cool before the next layer is poured.

- CLSM is relatively inexpensive.

• Strong grout is a runny grout with compressive strengths in the normal concrete range. This formulation is advantageous near the top of the tank because:

- The runny consistency of the grout is advantageous for filling voids near the top of the tank created around risers and tank equipment. The grout would be injected in such a manner as to ensure that voids were filled to the extent practicable. This may involve several injection points, each with a vent.

- A relatively strong grout will discourage an intruder from accidentally accessing the residual waste if institutional control of the area were lost.

• If required, a low-maintenance engineered cap, such as a clay cap, would be added to reduce rainwater infiltration. First, the area around the tank would be backfilled with soil to cover all risers, equipment, and other protuberances. The cap would then be placed so that rain falling on the area will drain away from the closed tank. Because the tanks are grouped into close groupings, a cap would probably be placed over an entire group of tanks in one area rather than over each tank individually.

Figure B-1. Typical tank closure configuration

Equipment Closure

In addition to the residual waste at the bottom of the tank, which is the major focus of closure activities, there will be residual contamination on equipment inside and near the tank, for example, slurry pumps used for waste removal, cooling coils inside the tank, transfer piping into and out of the tank, and the secondary containment system and leak detection system for the tank. In addition, the tank farms include other equipment for processing the waste, i.e., evaporators, pump tanks, and interarea transfer lines from F- to H-Area and from H-Area to DWPF and Saltstone. The amount of contamination on this equipment is small compared to the amount of contamination in the tanks. Before closure of a tank or group of tanks, any associated equipment that is planned for reuse (or planned for removal for some other reason) would be removed. Much of this equipment is not contaminated as it does not come in contact with the waste. The pieces of equipment that are contaminated and that would remain after the closure would be decontaminated in a manner similar to the waste tanks (generally by flushing with water or oxalic acid). Then, all remaining equipment would be filled with pumpable backfill material, similar to that used for tank closure (grout or CLSM) to the extent practical. Existing openings such as hand holes and pipe breaks would be used as much as possible to fill the equipment. Some equipment has small voids that do not present a concern for settling after closure, they may be left unfilled.

Appendix C
Comparative Analyses of Pre-closure HLW Tank Operations and Post-closure Conditions

The 51 HLW tanks and ancillary equipment are part of SRS's Liquid Radioactive Waste Handling Facilities (LRWHF). Safety analysis supporting the current operation of the LRWHF has evaluated over 250 accidents; seven of the accidents were rated highest risk, 55 accidents were rated moderate risk and 216 accidents were rated lowest risk. Of the 62 accidents considered highest risk or moderate risk, some were evaluated to be incredible due to an extremely low frequency of occurrence and others were evaluated not to adversely impact the safe operation of the facilities. Thirteen were analyzed as Design Basis Accidents (DBA). The 13 design basis accidents for the pre-closure operation of the LRWHF include the following:

• Seismic Event

• Tornado

• Vehicle Crash

• Transfer Errors

• Benzene Generation from Oxalic Acid and STPB

• Evaporator Breach

• Chemical Spills-Nitric Acid

• Deflagration in Filtrate Hold Tank

• Deflagration in Filter Cell

• Detonation in Evaporator

• Deflagration Transfer Facility

• Liquid Leaks/Spills

• Benzene Uptake - Filter Stripper Building

The following sections describe each accident scenario and assess the scenario impacts in the post closure environment.

Seismic Event

The Department of Energy requires an evaluation of a Design Basis Accidents (DBA) seismic event. The tank farms and associated facilities are assumed to be operating at the time of the seismic event in a state that will generate the worst case scenario. None of the waste tanks are damaged such that an airborne release occurs. An airborne release results from failure of above ground or near surface transfer lines, assuming a transfer is in progress at the time of the event, and from failure of the evaporators.

Closure of the HLW tanks involves removal or stabilization of the ancillary equipment after the completion of bulk waste removal. With these tasks completed, the source for any possible airborne releases (i.e., surface transfer lines and the evaporators) during a seismic event will have been removed from service. Additionally, the remaining waste heel will be sealed in grout and the remainder of the tank filled with CLSM. This will eliminate any possible airborne release originating from a waste tank during a seismic event after closure.

Tornado

In the current operational accident analysis the Tank Farms are assumed to be operating (i.e., full of HLW) at the time of a tornado/high wind event in a state that will generate the worst case scenario aftermath. All waste tanks are below ground. Type I, Type II, and Type III or IIIA waste tanks are protected by at least 22 inches of concrete roof from tornado driven missiles. Type IV waste tanks have at least seven inches of reinforced concrete dome with blacktop above the dome as protection against tornado driven missiles. During a tornado event small lightweight inspection plugs on the tank top could be dislodged. Although some of the tank vapor would escape, no liquid waste would be lost. Additionally, transfer/slurry pumps extending high enough above the risers, as in salt or sludge removal, could be dislodged. This would also result in a loss of vapor, but no liquid waste would escape a tank.

After tank closure, all tank penetrations would be sealed and ancillary equipment (piping, pumps, etc.) would have been removed. There would be no penetrations in the tank. Additionally, after the closure, the tank would be filled with CLSM and there would be no vapor space in the tanks. The remaining waste heel in the tanks would be sealed in grout and covered with many feet of CLSM in addition to the tank walls and tank top. Consequently, there is no mechanism for a tornado induced release.

Vehicle Crash

Vehicles could contact certain above-grade processing equipment, causing HLW leaks and/or spills to occur. Electric carts, automobiles, light trucks, heavy trucks, and cranes are examples of vehicles that may be in the vicinity of the process equipment from time to time. A crane falling on equipment or dropping significant loads on equipment is another potential initiator that could release radioactivity to the environment. All of these potential initiators are included in the analysis of a vehicle crash.

No main traffic arteries or through roadways exist in the immediate proximity of either tank farm. Therefore, no high-speed vehicular traffic occurs in either tank farm area. In addition, waste tanks are massive structures whose exterior walls are either underground or surrounded by an earthen berm, making them impenetrable by a vehicle of any type. The exposed surfaces of waste tank concrete roofs are generally located at an elevation that is a foot or more higher then the elevation of adjacent vehicle roadways. This elevation difference would thwart encroachment by most vehicles, especially at the low speeds required to negotiate the roadways in the tank farms. Studies have shown that tank tops would also withstand the impact loading of a three-ton truck. No release of HLW from a waste tank would occur due to a vehicle impact.

After tank closure all but a small waste heel (sealed in grout) will be removed from the tank, all ancillary equipment will be removed or stabilized, all tank penetrations will be sealed and the tank will be filled with grout and CLSM. Essentially filling a tank with backfill material will greatly increase the tank integrity and provide an impervious barrier with respect to vehicle impact. During tank closure the grout and CLSM will be pumped from a distance into the tanks, thus eliminating the need for increased vehicle traffic in the immediate vicinity of the tanks during the closure process.

Transfer Errors

During current operations of the tank farms, waste handling requires multiple transfers of liquid solutions or slurries. An incorrect transfer of waste (transfer error) within the LRWHF is an operational event that may result in a release of HLW. Potential transfer errors encompass a broad range of operator activities that can lead to various types of material release.

Tank closure will occur after bulk waste removal. Therefore, there will be no waste transfers after tank closure.

Benzene Generation from Oxalic Acid and STPB

This accident is an operational event involving a benzene release that is generated by the mixing of sodium tetraphenylborate (STPB) and oxalic acid. The STPB is delivered directly to the pumping station in the cold feed area by tanker trucks that have an assumed maximum volume of 5000 gallons. Although STPB is directly delivered to the pumping station in the Cold Feed Area, the possibility still exists that the STPB and oxalic acid can inadvertently be mixed in the Cold Feed Area.

This accident does not involve the waste tanks and, therefore, is not germane to discussion of the tank closure project.

Evaporator Breach

An evaporator breach does not involve the HLW tanks. Furthermore, after bulk waste removal, the evaporators will be out of service. Therefore, a discussion of an evaporator breach is not germane to the tank closure project.

Chemical Spills-Nitric Acid

Nitric acid is stored in a 10,000 gallon tank in the Effluent Treatment Facility (ETF). Consequently, a nitric acid spill would not originate from the HLW tanks. Therefore, a discussion of a nitric acid spill is not germane to the tank closure project.

Deflagration in Filtrate Hold Tank

The function of the Filtrate Hold Tank (FHT) is to hold the filtrate (or spent wash water) until it is analyzed for transfer acceptability. The filtrate is a decontaminated salt solution. After bulk waste removal, the FHTs would be out of service and, therefore, are not germane to the tank closure project.

Deflagration in Filter Cell

The filter and associated piping are located inside a shielded area of the Filter Building called the filter cell. After bulk waste removal, the Filter Building will be out of service. Additionally, a deflagration in a filter cell does not involve the HLW tanks. Therefore, a discussion of a deflagration in a filter cell is not germane to the tank closure project.

Detonation in Evaporator

By the time the HLW Tanks are closed, the evaporator will be out of service. Therefore, accidents associated with the evaporator are not germane to the tank closure project.

Deflagration Transfer Facility

The transfer systems move waste from one tank or facility to another tank or facility. Closure of the HLW tanks will occur after the bulk waste removal (i.e., after the waste tanks have been emptied). Therefore, the transfer systems will not be in service and accidents involving the transfer systems would not be possible.

Liquid Leaks/Spills

This is an operation event that involves the leakage or spillage of HLW. The leaks considered in this scenario are those caused by piping or equipment failure. Closure of the HLW tanks will occur after the bulk waste removal (i.e., after the waste tanks have been emptied). Therefore, the transfer systems will not be in service and accidents involving the transfer systems would not be probable.

Benzene Uptake - Filter Stripper Building

Benzene is released through the stack during normal stripper column operation and during stripper column cleaning with oxalic acid. If benzene is accidently ignited in the stack, a deflagration may occur, resulting in an overpressure, with the potential to rupture the stack. The stack outlet is 90 feet above ground level, but a rupture may cause the stack to release unburned benzene at a lower height. This is an operational event and could potentially expose nearby personnel to the hazardous chemicals being released from the stack.

Closure of the HLW Tanks will occur after the bulk waste removal (i.e., after the waste tanks have been emptied). Therefore, the Filter Stripper Building will not be in service and accidents involving the Filter Stripper Building would not be germane to the tank closure project.

Appendix D
Response to Public Comments

APPENDIX D. INTRODUCTION

On March 23, 1996, the U. S. Department of Energy Savannah River Operations Office (DOE-SR) decided to initiate the preparation of an Environmental Assessment (EA) for the closure of the high-level waste tanks in F- and H-Areas on the Savannah River Site (SRS). This document preparation effort was implemented in compliance with the National Environmental Policy Act (NEPA) of 1969, as amended, the requirements of the Council on Environmental Quality Regulations for Implementing NEPA (40 CFR Parts 1500-1508), and the DOE Regulations for implementing NEPA (10 CFR 1021). The assessment of environmental consequences of Federal actions that may affect the quality of the human environment are required under NEPA. Based on the potential for impacts described in the resultant document, DOE will either publish a Finding of No Significant Impact (FONSI) or prepare an environmental impact statement (EIS). An initial internal scoping meeting was held on March 28, 1996 for this EA pursuant to the guidelines specified in the Savannah River Site NEPA Program Quality Assurance Plan Preparation and Review of Environmental Assessments (WSRC-RP-96-010). The proposed action, alternatives, specific assessment studies needed, project time frame, and public participation were discussed at that meeting. Preparation of the preliminary draft EA was begun in late Match of 1996. The preliminary draft EA was completed in late May of 1996. As required in 10 CFR 1021, the predecisional draft EA was transmitted to the states of South Carolina and Georgia on June 4, 1996 for review and comment. The end date for comments from the states was scheduled for July 20, 1996. A total number of six responses were received, ranging in length from one to six pages. Agency responses numbered one; individuals provided five comment responses. As indicated in in the comment responses, the EA has been changed, where appropriate, to address commentors concerns.

The comments and responses follow:

Author	Number	Page Number
Booher	L-01	D-2
Booher	L-02	D-3
DOE	Response to L-01 & L-02	D-4
Maxted	L-03	D-5
DOE	Response to L-03	D-6
Beaumier	L-04	D-7	D-8	D-9	D-10	D-11	D-12
DOE	Response to L-04	D-13	D-14	D-15	D-16	D-17	D-18	D-19	D-20	D-21
Graf	L-05	D-22	D-23	D-24
DOE	Response to L-05	D-25	D-26	D-27	D-28	D-29	D-30	D-31
SC	L-06	D-32

GLOSSARY, ACRONYMS, & ABBREVIATIONS

GLOSSARY

Annulus. Ringlike structure around a primary containment.
B-25 Box. Steel box used to contain radioactive waste for burial.
Bulk Waste. The major fraction of waste in a tank. It can be removed by conventional means (eg., pumping).
Cap. An impermeable layer of material placed over an area to reduce the amount of rain water migrating down through the soil and carrying away contaminants into the groundwater. Caps are often constructed of layers of clay, gravel, and vegetated topsoil.
Controlled Low Strength Material. A self-leveling, pumpable, concrete composed of sand and cement formers.
E-Area Vault. Project which consists of several types of facilities (i.e., below-grade concrete structures, on-grade concrete structures within excavated areas) that will dispose of designated waste types (low-activity, intermediate-level tritiated and nontritiated, and long-lived waste) of low radioactive waste materials.
Fission Products. Nuclei from fission of heavy elements (primary fission products); also, the nuclei formed by the decay of primary fission products, many of which are radioactive.
Groundwater. The supply of fresh water under the Earth's surface.
Grout. Cement-like mixture which is pumpable, easily flows into voids, and hardens upon setting.
Heel. The residual amount of waste left on the bottom of a tank which cannot be practically removed.
High-Heat Waste. Freshly generated waste that contains a large concentration of short-lived radioactive radionuclides from the first extraction cycle of a separations process. High-heat waste (HHW) is aged to allow radioactive decay to prevent the potential discharge of harmful levels of radiation.
Insoluble Sludge. A thick layer of various heavy metals and long-lived radionuclides that will not dissolve and that separate out of the waste over time and settle to the bottom of the waste tank.
Leachate. Liquid that has percolated through solid waste of other media and that contains dissolved or suspended contaminants extracted from those materials.
Leaching. The process in which a soluble component of a solid or mixture of solids is extracted as a result of percolation of water around and through the solid.
Low-Heat Waste. Second or subsequent extraction cycle waste generated from a separation process. Low-heat waste (LHW) contains few radionuclides and does not require aging (radioactive decay). Low-heat waste is also generated in reactor areas, the Defense Waste Processing Facility, and other SRS production support facilities. (See high-heat waste)
Outcropping. Place where groundwater is discharged to the surface. Springs, swamps, and beds of streams and rivers are outcrops of the uppermost water table.
Permeability. Ability of rock, soil, or other substance to transmit a fluid.
Person-rem. The radiation dose to a given population; the sum of the individual doses received by a population segment.
Pumpable Backfill. A grout-like mixture. By controlling the amount of hydrating materials used, the strenght of the set can be varied from strong (concrete) to moderate (comparable to hard soil).
rad. Unit of absorbed dose deposited in a volume of material.
rem. Unit of dose equivalent (absorbed dose in rads x the radiation quality factor). Dose equivalent is frequently reported in units of millirem (mrem) which is one-thousandth of a rem.
Saltcake. Concentrated waste in the form of crystallized salts resulting from the evaporation of liquid high-level waste.
Saltstone. Low radioactivity fraction of high-level waste mixed with cement, flyash, and slag to form a concrete block.
Seepline. Place where groundwater discharges or outcrops to the surface, often near creeks and streams.
Sludge. The precipitation solids (primarily oxides and hydroxides) that settle to the bottom of the storage tanks containing liquid high-level waste.
Slurry. A suspension of solid particles (sludge) in water.
Supernate. The radioactive layer of highly mobile liquid containing soluble salts; the supernate remains above the saltcake and/or insoluble sludge in a waste tank.
Tank Farm. An installation of (usually interconnected) underground tanks for the storage of high-level radioactive liquid wastes.
Transuranic. Alpha-emitting elements heaver than uranium.
Vadose Zone. Soil zone located above the water table.

Acronyms

CERCLA	Comprehensive Environmental Response, Compensation, and Liability Act
CLSM	Controlled Low-Strength Material
DBA	Design Based Accidents
DOE	Department of Energy
DWPF	Defense Waste Processing Faciity
EA	Environmental Assessment
EIS	Environmental Impact Statement
EPA	Environmental Protection Agency
ESP	Extended Sludge Processing
ETF	Effluent Treatment Facility
FFA	Federal Facility Agreement
FHT	Filtrate Hold Tank
HHW	High-Heat Waste
HLW	High Level Waste
ITP	In-Tank Precipitation
LHW	Low-Heat Waste
LRWHF	Liquid Radioactive Waste Handling Facilities
MOA	Memorandum of Agreement
NEPA	National Environmental Policy Act
NPDES	National Pollutant Discharge Elimination System
RCRA	Resource, Conservation, and Recovery Act
SCDHEC	South Carolina Department of Health and Environmental Control
SMDF	Saltstone Manufacturing and Disposal Facility
SRS	Savannah River Site
STPB	Sodium Tetraphenylborate

Abbreviations for Measurements

ft	Feet
gal	Gallon
ha	Hectar
hr	Hour
km	Kilometer
L	Liter
m	Meter
mi	Mile

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