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3.3 DEVELOPMENT OF ALTERNATIVES

This section explains the process followed to develop and select alternatives for remediating the tank waste, alternatives for implementing the remediation of the tank waste, and remediating the cesium and strontium capsules. This section also discusses TWRS activities that are beyond the scope of this EIS.

3.3.1 Tank Waste

3.3.1.1 TWRS Elements

Final remediation of TWRS involves three distinct activities: remediation of the tank waste, disposition of the tanks and all associated equipment (a process called closure), and decontamination and decommissioning of any new facilities constructed to remediate the tank waste. These activities are described in this section.

Remediating Tank Waste

Remediating tank waste in the 177 underground tanks and approximately 60 MUSTs is the subject of this EIS and is discussed in detail in Section 3.3.1.2.

Disposition of the Tank Farms (Closure)

The final disposition of the tanks and associated equipment and the remediation of contaminated soil and groundwater associated with leaks from the tanks is a process called closure. Closure is not within the scope of this EIS because there is insufficient information concerning the amount of contamination to be remediated. The amount and type of waste that ultimately remains in the tanks after remediation may also affect closure decisions. The Notice of Intent to prepare the TWRS EIS stated that: "The impacts of closure cannot be meaningfully evaluated at this time. DOE will conduct an appropriate NEPA review, such as an EIS to support tank closure, in the future" (59 FR 4052).

In response to emerging technical information and the need to support DOE's integrated approach to remediating the Central Plateau and the Hanford Site as a whole, DOE will prepare a future NEPA analysis to address tank farm closure and other issues associated with TWRS remediation. The analysis will address alternatives for closing the tank farms including disposition of the tanks and associated equipment, residual waste remaining after retrieval, and contaminated soils; resolution of emerging information concerning contamination of the vadose zone; and the integration of tank farm closure with the remediation of other Central Plateau areas. To support this analysis, DOE is implementing the Hanford Tanks Initiative to obtain operational experience on a number of important factors, which will provide data to support decisions on closure of the tank farms. Data that will be obtained include information on waste retrieval methods and waste volume sampling and characterization of residual waste, as discussed in Section 3.2.1.4.

Some of the decisions to be made concerning how to treat and dispose of tank waste may impact future decisions on closure, so the tank waste alternatives provide information on how tank waste remediation and closure are interrelated. Under the Tri-Party Agreement, the tanks are classified as hazardous waste management units that eventually would be closed under the State Dangerous Waste Regulations (WAC 173-303) and the requirements of the Tri-Party Agreement.

Three options exist for closure of the tanks. The first option is clean closure, which would involve the removal of all contaminants from the tanks and associated equipment, soil, and groundwater until natural background levels or health-based standards are achieved.

The second option is modified closure, which would involve a variety of closure methods but require periodic (at least once after 5 years) assessments to determine if the modified closure requirements are met. If modified closure requirements were not being met, additional remediation would be performed. Modified closure is a method specific to the Hanford Site Permit under the State Dangerous Waste Regulations (WAC 173-303).

The third option is closure as a landfill, which would involve leaving some waste in place with corrective action taken for contaminated soil and groundwater performed under post-closure requirements. This type of closure usually involves the construction of a low permeability cover over the contaminated media to reduce water infiltration and prevent inadvertent human intrusion.

Although sufficient information is not available to make final decisions on closure, some of the alternatives affect future closure decisions, so information is provided to allow the public and decision makers to understand how the alternatives would be interrelated with future closure of the tank farm system. For example, some of the alternatives addressed in the EIS involve removing most of the waste from the tanks (the ex situ alternatives) and would not substantially affect options for future closure decisions. Conversely, some of the alternatives do not involve removing the waste from the tanks (the in situ alternatives) but rather, would treat and dispose of the waste in the tanks. These alternatives include placing a low permeability cover over the tank farms to reduce water infiltration and prevent inadvertent human intrusion (e.g., Hanford Barrier). This would be considered closure as a landfill.

DOE plans to implement a program, the Hanford Tanks Initiative, to gather information and reduce uncertainties associated with tank closure. This would include developing and demonstrating systems to determine the residual waste volumes remaining in a tank following retrieval. The residual waste would be analyzed by developing systems for sampling and characterization. Site specific information on tank leaks would be obtained by developing systems to sample and characterize contamination in the soils surrounding the tanks. The information that would be gathered through the Hanford Tanks Initiative would be used to establish processes and criteria for future closure options.

Clean closure would be precluded by implementing the In Situ Fill and Cap and In Situ Vitrification alternatives because these alternatives would involve leaving most of the waste in place and placing a low permeability cover over the tank farms. This would constitute closure as a landfill. Similarly, the Ex Situ/In Situ Combination 1 and 2 alternatives would preclude clean closure of the tanks that contain waste that is not retrieved; 107 tanks for the Ex Situ/In Situ Combination 1 alternative and 152 tanks for the Ex Situ/In Situ Combination 2 alternative. The tanks that contain waste that is retrieved could be clean closed. The ex situ alternatives would not preclude clean closure.

For purposes of comparing the alternatives, a single and consistent method of closure was assumed for all of the alternatives. Closure as a landfill was chosen as the representative closure method for purposes of analysis and is included in all of the alternatives (except the No Action and Long-Term Management alternatives). This does not mean that closure as a landfill is proposed or necessarily would be selected in the future. It is included to allow a meaningful comparison of the in situ and ex situ alternatives and to provide information to the public and the decision makers of the total cost and impacts of final restoration of the Site.

Because decisions on closure cannot be made at this time, but are interrelated with decisions to be made on remediation of the tank waste, the EIS presents an analysis of impacts with and without closure in Section 5.0. In each applicable subsection of Section 5.0, the impacts of the activities associated with remediating the waste are presented first. This is followed by the presentation of the combined impacts of remediating the tank waste and closing the tank farms by closure as a landfill. This provides the public and the decision makers with information on the impacts of the issues that are ripe for decision making (remediation of the tank waste) and information on the total project impacts (remediation and closure) as well as how they may be interrelated with the decisions on remediation of the tank waste.

Decontamination and Decommissioning

Decontamination and decommissioning of new facilities constructed to implement any of the alternatives are not evaluated in detail in this EIS because decisions on the appropriate method would not be required until the treatment and disposal of waste is complete (which is up to 30 years in the future) and because insufficient information is available presently to provide a meaningful evaluation. However, decontamination and decommissioning of these facilities is foreseeable. Therefore, the cost, personnel requirements, and volume of contaminated and noncontaminated materials resulting from decontamination and decommissioning were developed and analyzed using general practice assumptions to show how tank waste remediation and decontamination and decommissioning are interrelated. This provides an assessment of the relative environmental impacts of future decontamination and decommissioning activities so that the alternatives can be meaningfully compared. DOE will conduct an appropriate NEPA review to support future decontamination and decommissioning decisions.

3.3.1.2 Alternatives for Remediating Tank Waste

A wide range of potentially applicable technologies exists for treating tank waste. One of the challenges for DOE and Ecology is to eliminate from consideration technologies that are not viable and develop a range of reasonable alternatives for detailed analysis and presentation in the TWRS EIS. This section describes how the alternatives were developed.

There is a distinction between technologies and alternatives. Technologies are specific processes (e.g., cesium ion exchange) that relate to a component (e.g., retrieval or treatment) of an alternative. Alternatives include a set of technologies, or building blocks, that have been engineered to work together, forming complete systems for accomplishing the purpose and need for action. Alternatives are made up of a number of technologies linked together.

The first step in developing alternatives was to screen out technologies that were not viable. The full range of available technologies for each component of the proposed action was evaluated, and technologies that were not viable were eliminated from further consideration. The technologies eliminated by this screening process are described in Section 3.8 and Volume Two, Appendix C.

After rejecting technologies that were not viable, a large number of potential technologies remained for inclusion in the EIS. It would not be practicable to develop alternatives that include all of the potential combinations of technologies. In accordance with NEPA, representative alternatives were developed for detailed analysis to bound the full range of reasonable alternatives. Upper, lower, and intermediate bounding alternatives were developed in terms of cost, risk, and technologies for the two primary decisions that affect environmental impacts: the amount of waste to be retrieved from the tanks and the degree of separations of retrieved waste into HLW and LAW. The full range of applicable technologies and alternatives therefore is included in the EIS.

Because representative alternatives were developed for detailed analysis in the EIS, there are many other viable technologies for individual components of the alternatives that could not be included. These technologies are included in Volume Two, Appendix B and could be substituted for one of the technologies that is included in an alternative without a substantial change in the impacts of that alternative. An evaluation was performed for each of the technologies identified in Appendix B. Where there would be changes in impacts, the changes are discussed in Volume Two, Appendix B. The level of analysis was dependent on the magnitude of the change on impacts.

The alternatives developed for presentation in the EIS were chosen to be representative of many of the possible variations of the alternative. The design information for all alternatives is at an early planning stage, and the details of the alternative that ultimately is selected and implemented may change as the design process matures. Therefore, the alternatives are intended to represent an overall plan for remediation at a level of detail sufficient for impact analysis and alternative comparisons.

NEPA requires that an EIS includes a No Action alternative, which addresses not taking the proposed action (i.e., not initiating the project). For the TWRS project, there is a management program in place to continue the safe management of the tank waste and the capsules; therefore, the No Action alternatives addressed in this EIS (continue the current waste management program), consist of the activities currently being conducted to safely manage the waste. Further, under the No Action alternatives , no new facilities would be constructed other than those for which decisions already have been made based on other NEPA reviews (e.g., the Safe Interim Storage EIS).

Since the late 1950's, there have been numerous studies analyzing alternatives for tank waste treatment and disposal. The technologies contributing to the alternatives presented in the EIS come from different sources. The initial set of technologies used in the report was obtained by reviewing literature for processing radioactive, hazardous, and mixed waste. The literature review was supplemented by several DOE-sponsored workshops on treatment technologies for Hanford Site tank waste. Objectives and technologies were also proposed for consideration in the EIS during the public scoping process.

Four general categories of response actions have emerged through the alternative identification process. These categories are: 1) continue waste storage in the tanks; 2) waste treatment and disposal in the tanks, referred to as in situ treatment, 3) waste treatment outside of the tanks in a processing facility, referred to as ex situ treatment, and 4) a combination of in situ and ex situ treatments. In situ waste treatment would not involve removing the waste from the tanks. Ex situ treatment would require that the waste be removed from the tanks for treatment and disposal.

Continued waste storage would not result in remediation of the waste but would postpone the impacts of the uncontrolled release of the waste. In situ alternatives eliminate the need for waste retrieval and would result in leaving all of the waste onsite following treatment. Ex situ alternatives require removing waste from the tanks for treatment and provide the opportunity to separate the waste into HLW and LAW components. The purpose of separating the waste is to meet onsite disposal requirements for LAW and minimize the volume of HLW requiring offsite disposal. Combination alternatives provide the opportunity to selectively retrieve waste for ex situ treatment based on waste type to achieve acceptable post remediation risk levels.

Ex situ alternatives provide for disposal of HLW at a potential geologic repository. Solely for the purpose of analysis, the potential geologic repository at Yucca Mountain, Nevada was assumed to be the final destination because it currently is being characterized to determine its suitability as a repository. It was assumed that the potential geologic repository would be operational and accept HLW generated by the ex situ alternatives (see Section 3.7 and Volume Two, Section B.10) .

New Technical Strategy

In January 1994, DOE, Ecology, and U.S. Environmental Protection Agency (EPA) renegotiated the Tri-Party Agreement, which led to a new proposed technical strategy for remediating the tank waste. This technical strategy provides the basis for the TWRS EIS Ex Situ Intermediate Separations alternative and includes the following activities:

• Retrieve present and future waste from all DSTs and SSTs;
• Separate the waste into HLW and LAW streams to the extent required to meet onsite disposal requirements for LAW and to maintain an acceptable volume of HLW for offsite disposal;
• Vitrify the LAW and dispose of it onsite in a near-surface disposal facility in a retrievable form;
• Vitrify the HLW and store it onsite at a designated storage facility for future disposal at the potential geologic repository; and

Implementation of Alternatives

There are many technical uncertainties associated with the alternatives for remediating the tank waste. These uncertainties involve the types of waste contained in the tanks and the effectiveness of the retrieval techniques, waste separations, waste immobilization, and cost of implementing the alternatives. These uncertainties exist because some of the technologies that may be implemented are first-of-a-kind technologies, have not previously been applied to the TWRS tank waste, or have not been applied on a scale as large as would be required for the TWRS tank waste.

Because of these uncertainties, DOE considered different approaches to implementing the alternatives to reduce the financial risk involved if one or more of the technical uncertainties could not be readily resolved. DOE identified two approaches to implementing the alternatives: full-scale implementation and phased implementation. Under full implementation, DOE would design, construct, and operate full-scale facilities to remediate the tank waste. Under phased implementation, either DOE or a private contractor would design, build, and operate demonstration-scale facilities to prove that the remediation concept would function adequately before constructing and operating full-scale facilities. All calculations performed for this EIS are based on DOE implementing the alternatives through the existing Management and Operations contractor system. This phased implementation approach has the potential to prove that the technologies work before committing large capital expenditures that could not be recovered.

A phased approach could be developed for any of the alternatives, but not all phased approaches would involve changes to environmental impacts from the full-scale approach. Therefore, not all phased approaches need to be addressed in the EIS. To decide which of the full-scale alternatives would need to have an associated phased implementation alternative addressed in this EIS, the following two criteria were used.

• Would the full-scale alternative involve large front-end expenditures of funds that could be lost if an unproven technology did not function adequately?
• Would the environmental impacts of the phased implementation approach be different than those of the full-scale alternative?

If either criterion were met, a phased approach would be included in the EIS.

Applying these criteria showed that most alternatives did not warrant a separate analysis of a phased implementation approach. A phased implementation approach to the No Action and Long-Term Management alternatives would not involve changes in environmental impacts, large front-end expenditures, or unproven technologies, so no phased approach was included in the EIS for these alternatives. A phased implementation approach to the In Situ Fill and Cap alternative would involve the simple process of filling several tanks as a demonstration, and therefore would not involve different environmental impacts or large front-end expenditures of funds that could be lost, so no phased approach was included in the EIS. Similarly, a phased approach to the In Situ Vitrification alternative would involve testing the in situ vitrification process first on MUSTs, then small tanks, and then large tanks. Although this technology previously has not been performed on the tank waste, it could be tested gradually without any differences in environmental impacts or large expenditures of funds that could be lost if the process did not function adequately. Therefore, the In Situ Vitrification alternative did not warrant a separate phased implementation alternative, and no phased approach was included in the EIS.

All of the ex situ alternatives involve the application of technologies that have not been applied to the tank waste and all would involve large front-end expenditures of funds to construct large, complex separations and immobilization facilities. The phased implementation approach for these alternatives would involve constructing and operating demonstration-scale facilities before constructing the full-scale facilities, and would result in environmental impacts substantially different than the full-scale implementation alternative. Therefore, a phased implementation alternative has been included in the EIS to bound the impacts for the ex situ alternatives.

The Phased Implementation alternative consists of two phases: a proof of concept or demonstration phase (Phase 1) and a full-scale treatment phase (Phase 2). Phase 1 would include the construction and operation of one combined separations and LAW vitrification facility and one combined separations, LAW vitrification, and HLW vitrification facility. A sufficient quantity of a variety of tank waste types would be processed to demonstrate the effectiveness of the process and provide the necessary data to design a full-scale treatment facility . Phase 2 would include completing tank waste remediation by constructing and operating new full-scale separations, LAW immobilization, and HLW vitrification facilities. The degree of separations into LAW and HLW was assumed to be similar to the Ex Situ Intermediate Separations alternative, and includes additional processes to separate out the strontium, technetium, and transuranic elements from the LAW.

The tank waste alternatives addressed in this EIS include:

• No Action;
• Long-Term Management;
• In Situ Fill and Cap;
• In Situ Vitrification;
• Ex Situ Intermediate Separations;
• Ex Situ No Separations;
• Ex Situ Extensive Separations;
• Ex Situ/In Situ Combination 1 ;
• Ex Situ/In Situ Combination 2 ; and
• Phased Implementation (preferred alternative).

The alternatives developed for detailed analysis cover the full range of actions as well as the No Action alternative. The tank waste alternatives range from waste containment with the Long-Term Management alternative to extensive processing (separating HLW from LAW fractions) and immobilization using new technologies with the Ex Situ Extensive Separations alternative. the relationship among the alternatives is shown in Figure 3.3.1.

Figure 3.3.1 Relationship Among TWRS EIS Alternatives

3.3.2 Cesium and Strontium Capsules

The cesium and strontium capsules currently are classified as waste by-product, and this EIS is only addressing measures to remediate the capsules when and if they are determined to have no productive uses. The development of alternatives to remediate the cesium and strontium capsules is much less technically complicated than for the tank waste.

There are two distinct activities related to remediation of the capsules: the disposition of the capsules, which is analyzed in this EIS; and decontamination and decommissioning of WESF, the current capsule storage facility. WESF is part of B Plant and would be decontaminated and decommissioned in the future with B Plant. This is not within the scope of the EIS.

3.3.2.1 Alternatives for Remediating Capsules

The alternatives for remediation of the capsules include No Action, disposal on the Hanford Site, or disposal off the Hanford Site either with or separate from the tank waste. None of these alternatives involve unproven technologies or the construction of major process facilities. The following capsule alternatives are addressed in this EIS:

• No Action (preferred alternative);
• Onsite Disposal;
• Overpack and Ship; and
• Vitrify with Tank Waste.