Amended Record of Decision: Savannah River Site Salt Processing Alternatives

AGENCY:

Department of Energy (DOE).

ACTION:

Amended record of decision.

SUMMARY:

The Department of Energy (DOE), pursuant to 10 CFR 1021.315, is amending its Record of Decision: Savannah River Site Salt Processing Alternatives issued on October 17, 2001 (66 FR 52752). At that time the Department decided to implement the Caustic Side Solvent Extraction (CSSX) technology, one of the alternative technologies evaluated in DOE/EIS-0082-S2 (Savannah River Site Salt Processing Alternatives Final Supplemental Environmental Impact Statement (SPA SEIS), June 2001) for separation of the high-activity fraction from the low-activity fraction of Savannah River Site (SRS) salt wastes. DOE has initiated design of the Salt Waste Processing Facility (SWPF), which will house the CSSX technology. Now, using technologies described in the SPA SEIS, DOE has decided to change the processing and disposition pathway for a fraction of the low activity salt waste currently stored in the F- and H-Area tank farms. This action is called Interim Salt Processing. When the SWPF becomes operational, the remaining (and by far the majority) salt waste will be processed through the SWPF using the CSSX technology as described in the SPA SEIS; this action is called High Capacity Salt Processing.

DOE will proceed with this interim approach because doing so will enable DOE to continue uninterrupted use of the Defense Waste Processing Facility (DWPF) to vitrify higher activity sludge waste for disposal at a geologic repository for spent nuclear fuel and high-level waste. It will also allow DOE to use SWPF at higher capacity as soon as it comes on line. This will allow DOE to complete cleanup and closure of the tanks years earlier than would otherwise be the case. That, in turn, will reduce the time during which the tanks—including some that do not have full secondary containment and have a known history of leak sites—continue to store liquid radioactive waste. Finally, Interim Salt Processing will make more tank space available for routine operations, thereby reducing the number of transfers among tanks and increasing the safety of operations. Therefore, Interim Salt Processing will accelerate the reduction of potential risk to the environment, the public, and workers.

DOE has prepared a Supplement Analysis (SA), Salt Processing Alternatives at the Savannah River Site (DOE/EIS-0082-S2-SA-01), in accordance with DOE National Environmental Policy Act (NEPA) regulations (10 CFR 1021.314) to determine whether implementation of Interim Salt Processing is a substantial change to the selected CSSX processing of salt waste or whether there are significant new circumstances or information relevant to environmental concerns such that a supplement to the SPA SEIS or a new EIS would be needed. Based on the SA, DOE has determined that a supplement to the SPA SEIS or a new EIS is not needed.

FOR FURTHER INFORMATION CONTACT:

Copies of the SPA SEIS and the 2001 Record of Decision are available on DOE's NEPA Web site at: http://www.eh.doe.gov/nepa . Copies of this amended Record of Decision, and the SA, will be available on DOE's NEPA Web site at: http://www.eh.doe.gov/nepa under DOE NEPA Documents. To request copies of these documents, please contact: The Center for Environmental Management Information, P.O. Box 23769, Washington, DC 20026-3769. Telephone: 800-736-3282 (in Washington, DC: 202-863-5084).

For further information regarding the processing and disposal of salt waste at the Savannah River Site, or to obtain copies of the SA discussed herein, or this amended Record of Decision, contact: Mr. Andrew R. Grainger, Savannah River Operations Office, U.S. Department of Energy, P.O. Box B, Aiken, SC 29802. Telephone: 803-952-8001. E-mail: drew.grainger@srs.gov.

For information on DOE's NEPA process, contact: Ms. Carol Borgstrom, Director, Office of NEPA Policy and Compliance, EH-42, U.S. Department of Energy, 1000 Independence Avenue, SW., Washington, DC 20585-0119. Telephone 202-586-4600, or leave a message at 800-472-2756.

SUPPLEMENTARY INFORMATION:

I. Background

DOE evaluated the environmental impacts of construction and operation of four alternative technologies for salt waste processing in the SPA SEIS. First, the concentrated supernate solution and solid saltcake (including the interstitial liquid) would be combined. The four salt processing technology alternatives considered in the SPA EIS all include initial separation of actinides (including plutonium and uranium) present in the salt solution by sorption on monosodium titanate (MST), followed by removal by filtration. The separated actinides would be sent to the DWPF for vitrification along with the sludge portion of the tank waste, which would not be processed through the salt processing facility. The remaining salt solution, which would have high concentrations of cesium (Cs) but very low concentrations of actinides after the MST step, would be further processed to remove most of the Cs.

The alternatives described in the SPA SEIS differ in the approach for removal of radioactive Cs from the salt solution. For each action alternative except Direct Disposal in Grout, most of the Cs would be extracted from the salt solution and incorporated into a vitrified waste form at the DWPF, along with the sludge portion of the tank waste and the actinides extracted in the MST step. The remaining low-activity salt waste stream would be sent to the Saltstone Production Facility, where it would be combined with grout in a homogeneous mixture and sent to the Saltstone Disposal Facility (also referred to as the Saltstone Vaults) for onsite disposal. Under the SEIS, all action alternatives but Direct Disposal in Grout would meet current permit conditions equivalent to Class A low-level waste. The Direct Disposal in Grout alternative would not meet the permit conditions due to high Cs concentrations. Under all action alternatives, the actinide concentration of the salt waste disposed in the Saltstone Disposal Facility would not exceed the Nuclear Regulatory Commission (NRC) concentration limits for Class A low-level waste, and would be about 10 nanocuries per gram.

DOE issued the Final SPA SEIS in June 2001 and in October 2001 DOE issued a Record of Decision selecting the preferred alternative described in the Final SPA SEIS—CSSX, with MST for removal of actinides—as the treatment technology for salt waste. DOE is currently designing the SWPF which will house the CSSX and MST treatment technologies.

The disposal of saltstone waste in the Saltstone Disposal Facility is subject to the requirements of section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA). NDAA section 3116 authorizes the Secretary of Energy, in consultation with the NRC, to determine that certain waste from reprocessing is not high-level waste and that disposal in a geologic repository is not required, if it meets certain criteria. DOE prepared a Draft section 3116 Determination for Salt Waste Disposal at the Savannah River Site in February 2005, and consulted with the NRC pursuant to section 3116 of the NDAA. Although not required by section 3116, DOE made the draft 3116 Determination available for public review concurrent with DOE's consultation with the NRC.

The NRC consultation process has been completed. On December 28, 2005, the NRC issued its Technical Evaluation Report of the U.S. Department of Energy Draft section 3116 Waste Determination for Salt Waste Disposal (TER). The TER presents information on DOE's salt waste processing strategy, the applicable review criteria, and the NRC's review approach, as well as the NRC's analysis and conclusions with respect to whether there is reasonable assurance that DOE's proposed approach can meet the applicable requirements of the NDAA for determining that waste is not high-level waste. As noted in its executive summary, “Based on the information provided by DOE to the NRC * * *, the NRC staff has concluded that there is reasonable assurance that the applicable criteria of the NDAA can be met provided certain assumptions made in DOE's analyses are verified via monitoring.”

DOE considered the NRC's TER, as well as the public comments on the Draft section 3116 Waste Determination, before issuing the section 3116 Waste Determination in January 2006. DOE also considered whether the comments on the Draft section 3116 Waste Determination raise issues or provide information that would affect the environmental discussion in the Salt Processing Alternatives SA and has determined that they do not.

In the section 3116 Determination for Salt Waste Disposal at the Savannah River Site DOE concluded that, as demonstrated in the section 3116 Determination for Salt Waste Disposal at the Savannah River Site and in consideration of DOE's consultation with the NRC, the solidified low-activity salt waste is not high-level waste and may be disposed of in the Saltstone Disposal Facility at SRS. DOE also stated that DOE will continue to take actions (such as sampling, monitoring, and ensuring vault inventory limits) to confirm the ongoing validity of the Determination and to explore additional actions to further enhance the protection of workers, the public, and the environment.

Interim Salt Processing and SWPF Operation ²

Since issuing the SPA SEIS and ROD, DOE has further considered options to maintain sufficient tank space to continue to vitrify sludge waste in the DWPF in the interim before the SWPF is operational. Continuing to operate DWPF will allow DOE to remove and vitrify sludge waste; prepare salt waste for treatment and disposal, and empty waste tanks so they may be closed. All of these actions will contribute to DOE's ability to continue to reduce the human health and environmental risk inherent in storage of high volumes of liquid radioactive waste.

DOE will now process the salt waste using a two-phase, three-part process. The first phase (herein referred to as Interim Salt Processing) will involve two parts to treat some of the lower activity salt waste: (1) Beginning in 2006, processing of a minimal amount of the lowest activity salt waste through a process involving deliquification, dissolution, and adjustment (DDA) of the waste; and (2) beginning in 2007, processing a minimal amount of additional salt waste with slightly higher activity levels using an Actinide Removal Process (ARP) and a Modular CSSX Unit (MCU), following deliquification, dissolution, and adjustment of saltcake. The second and longer term phase, herein referred to as High Capacity Salt Processing, is identical to the CSSX technology as presented in the SPA SEIS and will, beginning in 2011, separate and process the remaining (and by far the majority) of the salt waste using the SWPF (augmented as necessary by ARP). The second phase will begin as soon as SWPF is constructed, permitted by the State of South Carolina, and becomes operational. The first, interim processing phase will cease at that time (except that ARP could be used as necessary to augment SWPF).

About 33.8 million gallons (Mgal) of salt waste are currently stored in underground waste storage tanks at SRS. This waste, along with future salt waste forecasted to be sent to the tank farms, will be processed through DDA, ARP/MCU, and the SWPF. DOE estimated in preparing the Section 3116 Determination that an additional 41.3 Mgal of unconcentrated salt waste would have been received by the Tank Farms between December 1, 2004, and the completion of salt waste processing. After both liquid removal by processing through the Tank Farm evaporator systems and later additions of liquid for saltcake dissolution and chemistry adjustments required for processing, approximately 84 Mgal (5.9 Mgal existing salt waste through the DDA process, 1.0 Mgal future salt waste through the DDA process, 2.1 Mgal existing and future salt waste through ARP/MCU, 69.1 Mgal existing salt waste through SWPF, and 5.9 Mgal future salt waste through SWPF) of salt solution will be processed by Interim Salt Processing and High Capacity Salt Processing resulting in approximately 168 Mgal of grout output from the Saltstone Production Facility to be disposed of in the Saltstone Disposal Facility.

In terms of curies, implementation of Interim Salt Processing followed by High Capacity Salt Processing will result in onsite disposal of 3.0 to 5.0 million curies (MCi), with the majority (about 2.8 MCi of 3.0 MCi) resulting from Interim Salt Processing, in the Saltstone Disposal Facility. This represents 1.3 to 2.2 percent of the approximately 223 MCi in the salt waste. DOE's current estimate is that 3.0 MCi, or 1.3 percent of the total will be disposed of in the Saltstone Disposal Facility, and 3.0 MCi is used in this document. The higher number of 5 MCi represents uncertainties in the radiological characterization of the salt waste.

Deliquification, Dissolution, and Adjustment, Actinide Removal Process, and Modular CSSX Unit

These facilities and processes are described in the Salt Processing Alternatives SA, and in greater detail in DOE's section 3116 Determination for Salt Waste Disposal at the Savannah River Site. The DDA process will be the first interim process used and will be used to process some of the lowest activity salt waste from 2006 until 2011 when the SWPF begins operation. The DDA process will also be used to prepare waste feed streams for the ARP and MCU and will operate in parallel with those facilities.

In 2007, ARP and MCU operations will be initiated to process slightly higher activity salt waste. ARP and MCU will use processes described in the SPA SEIS (MST treatment and CSSX), the same technologies that will be incorporated in the SWPF, which will process about 98.7 percent of the 223 million curies in salt waste.

The ARP will be comprised of the actinide removal process that was described as part of the pilot plant, which also included a low-capacity CSSX capability, in the SPA SEIS. In order to take advantage of existing infrastructure and minimize construction costs, DOE will modify existing SRS facilities 512-S (formerly the Late Wash Facility) and 241-96H (formerly the filter building portion of the In-Tank Precipitation facility). The MCU will house a low-capacity CSSX technology, similar to the pilot plant described in the SPA SEIS. The MCU is being constructed in the former cold feeds area of the In-Tank Precipitation facility. The SA provides further details of the new and existing facilities and processes that will be used for Interim Salt Processing.

Regulatory Requirements

A modification to the Saltstone Disposal Facility Industrial Solid Waste Landfill (ISWL) permit, issued by the South Carolina Department of Health and Environmental Control (SCDHEC), will be required prior to implementation of Interim Salt Processing. The current Saltstone Disposal Facility ISWL permit authorizes disposal of waste with radionuclide concentrations comparable to Class A low-level waste limits (10 nCi/g) as defined in NRC regulations at 10 CFR 61.55. SCDHEC under its State wastewater permitting authority issued the permit. The permit requires DOE to notify SCDHEC if the characteristics of wastes to be disposed in the Saltstone Disposal Facility would change, as will be the case with the higher concentrations of radionuclides (about 0.2 Ci/gal rather than about 0.1 Ci/gal, and about 41 nCi/g actinides rather than less than 10 nCi/g) in saltstone that will be disposed when DOE implements Interim Salt Processing. DOE has submitted a request for a modification to the Saltstone Disposal Facility ISWL permit. The requested modification would cover waste with concentrations less than the NRC Class C limits (100 nCi/gm).

II. Decision

DOE has decided to implement Interim Salt Processing, followed by High Capacity Salt Processing using the CSSX technology when the SWPF becomes operational. DOE will change the processing and disposition pathway for a fraction (about 1.3 percent, or about 3.0 MCi) of the salt waste currently stored in the F- and H-Area tank farms. DOE will use the DDA process to segregate supernate and interstitial liquid from saltcake in order to send salt waste with low curie content (about 2.5 MCi, or about 6.9 Mgal) to the Saltstone Production Facility, where it will be combined with chemicals to form a grout matrix and sent to the Saltstone Disposal Facility. The waste processed with DDA will, after solidification, have an average Cs concentration of about 0.2 Ci/gal and actinide concentration of about 41 nCi/g. DOE will also use the DDA process to dispose of 0.24 Mgal of relatively low activity salt solution currently stored in Tank 48. DOE will process this waste without removal of radionuclides by combining the stream with another salt waste stream, currently planned to be the low-activity liquid recycle waste stream from the DWPF. About 2.1 Mgal of salt waste with slightly higher curie content will be prepared for processing through the ARP and MCU; about 0.3 MCi, or about 2.1 Mgal, will be disposed of in the Saltstone Disposal Facility. When SWPF becomes operational in about 2011 the CSSX technology will be used to process the inventory of salt waste that was not processed during interim salt processing. DOE expects to process about 98.7 percent (about 220 MCi) of the salt waste inventory using the CSSX technology as described in the SPA SEIS. After processing in the SWPF waste sent to the Saltstone Disposal Facility will have a Cs concentration of about 0.1 Ci/gal and actinide concentration of less than 10 nCi/g.

III. Basis for the Decision

DOE has initiated design of the Salt Waste Processing Facility (SWPF), which will house the CSSX technology selected in the Record of Decision. Now, using technologies described in the SPA SEIS, DOE has decided to change the processing and disposition pathway for a fraction of the salt waste currently stored in the F- and H-Area tank farms. This action is called Interim Salt Processing. When the SWPF becomes operational, the remaining salt waste will be processed using High Capacity Salt Processing through the SWPF using the CSSX technology as described in the SPA SEIS.

If DOE is to be in a position to continue removal and vitrification of the high-activity sludge between now and the startup of the SWPF, including removing sludge waste from the tanks that lack full secondary containment, and to operate the SWPF efficiently after its construction is complete, DOE must proceed with Interim Salt Processing. The only practical way DOE will be able to move forward with sludge vitrification without significant disruption and delay, and assure efficient operation of the SWPF, is to use interim salt processing technologies to remove and dispose of a limited amount of the salt waste currently in the tanks during this interim period. Otherwise, DOE would be forced to decrease, postpone, and eventually halt the on-going activities to remove and stabilize tank waste that currently are reducing risk to the occupational workers, the public, and the environment.

IV. Supplement Analysis

To determine whether the proposed action warrants a supplement to the SPA SEIS or a new EIS, DOE prepared the SA, Salt Processing Alternatives at the Savannah River Site (DOE/EIS-0082-S2-SA-01). In the SA DOE compared the impacts of implementing Interim Salt Processing followed by High Capacity Salt Processing to the impacts of the salt processing alternatives evaluated in the SPA SEIS.

Using the DDA process from 2006 until about 2011, salt waste with a Cs concentration of about 0.2 Ci/gal and an actinide concentration of about 41 nCi/g, totaling about 2.5 MCi, will be sent to the Saltstone Production Facility and then to the Saltstone Disposal Facility.

Salt waste processed through the ARP and MCU, which will operate from 2007 until the SWPF becomes operational will have a Cs concentration of about 0.1 Ci/gal and an actinide concentration comparable to SWPF waste (i.e., less than 10 nCi/g) after processing, and will result in about 0.3 MCi processed through the Saltstone Production Facility for disposal at the Saltstone Disposal Facility. These concentrations are the same as those described in the SPA SEIS for salt waste processed using the CSSX technology.

After the SWPF becomes operational in 2011, waste sent to the Saltstone Disposal Facility will have concentrations the same as those evaluated in the SPA SEIS, until waste processing is completed. In all, implementing Interim Salt Processing followed High Capacity Salt Processing using the CSSX technology at the SWPF will result in disposal of about 3.0 MCi, or 1.3 percent of the total curies contained in the salt waste, at the Saltstone Disposal Facility.

The SA addressed the impacts of the processing and disposal of higher concentrations of actinides during Interim Salt Processing than evaluated in the Salt Processing Alternatives SEIS. These higher concentrations will be found in that fraction of the salt waste segregated using the DDA process and sent directly for disposal without treatment in the ARP and MCU.

For the analysis presented in the SA, DOE conservatively assumed the entire salt waste inventory, processed through the SWPF using the CSSX for the operating life of the facility, would be sent to the Saltstone Production Facility with an actinide concentration of 100 nCi/g, the concentration limit for Class C waste. However, when Interim Salt Processing is implemented, concentrations will be less. That is, about 41 nCi/g resulting from the DDA process will be sent to the Saltstone Production Facility without treatment in ARP and MCU from 2006 until about 2011 when the SWPF becomes operational. DOE estimates that only about 6.8 Mgal or about 6 percent of the total salt waste inventory will have an average concentration of about 41 nCi/g. For the SA analysis DOE used the same Cs concentration DOE used for the SPA SEIS. The differences in impacts are therefore attributed solely to the increased actinide concentration.

Short-Term Impacts

As evaluated in the SPA SEIS, short-term impacts are incurred during operation of the salt waste processing facilities, and long-term impacts are those resulting from release of disposed radionuclides from the Saltstone Disposal Facility. As described in the SA, differences in short-term impacts resulting from implementing Interim Salt Processing followed by SWPF operation using the CSSX technology will be small compared to operation of the CSSX technology as described in the SPA SEIS. Modifications to the Saltstone Production Facility were completed within the existing structure and result in no new land disturbance. Impacts from construction of the MCU will not differ from those described for the pilot plant in the SPA SEIS. The existing 512-S and 241-96H facilities will be modified for the ARP and will be operated remotely. No adverse impacts are anticipated from construction. Implementation of Interim Salt Processing will not necessitate changes in the design or operation of the SWPF.

There is the potential for short-term impacts to the health of workers and the public due to radiation doses from airborne releases of Cs and actinides from processing activities. For example, the dose to the maximum exposed individual would increase from the 0.31 millirem analyzed under the Caustic Side Solvent Extraction alternative in the SPA SEIS to 0.58 millirem (due to increased actinide concentrations in that portion of the salt waste segregated using DDA but not treated using ARP and MCU before disposal). Similar small increases would occur in involved worker doses and non-involved worker doses. The 0.31 millirem dose to the maximum exposed individual would result in a probability of a latent cancer fatality of about 2 chances in 1,000,000 (2.0 × 10⁻⁶). The 0.58 millirem dose to the maximum exposed individual would result in a probability of a latent cancer fatality of about 3.7 chances in 1,000,000 (3.7 × 10⁻⁶).

Long-Term Impacts

In the SA, DOE compares calculated doses and impacts from the SPA SEIS (the SWPF using the CSSX technology) and the increased actinide concentrations in the Saltstone Disposal Facility from implementing Interim Salt Processing followed by SWPF operation. Three scenarios are used. In the Agricultural Scenario an individual is assumed to unknowingly farm and constructs and lives in a permanent residence on the vaults. At 100 years post-closure a sufficient layer of soil would be present over the still-intact disposal vaults so that the resident would be unaware that the residence was constructed over the vaults. At 1,000 years post-closure the saltstone is assumed to have weathered sufficiently so that the resident could construct a residence without being aware of the presence of the saltstone.

Under the Agricultural Scenario the doses and latent cancer fatalities resulting from Interim Salt Processing followed by SWPF operation using the CSSX technology increase slightly. Under the Residential Scenario at 100 Years, impacts from Interim Salt Processing would be comparable to Caustic Side Solvent Extraction analyzed in the SPA SEIS. For the Residential Scenario at 100 Years doses are dominated by Cs, which has largely decayed by 1,000 years post-closure.

When Interim Salt Processing followed by SWPF operation using the CSSX technology is implemented, waste with a concentration of about 41 nCi/g resulting from the DDA process without ARP and MCU treatment will be sent to the Saltstone Disposal Facility until SWPF becomes operational. Using ARP and throughout the operating life of the SWPF, salt waste sent to the Saltstone Disposal Facility will have actinide concentrations of 10 nCi/g or less. Long-term impacts will be less than shown in the SA when DOE implements Interim Salt Processing followed by SWPF because the actual inventory of actinides disposed of in the Saltstone Disposal Facility will be less than assumed in the calculation.

V. Conclusions

DOE will process about 98.7 percent of the salt waste inventory (about 220 of about 223 MCi) using the CSSX technology as described in the SPA SEIS. When SWPF becomes operational the CSSX technology will be used to process the inventory of salt waste that was not processed during interim salt processing. Interim Salt Processing followed by High Capacity Salt Processing through SWPF using the CSSX technology does not constitute a substantial change in actions previously analyzed and does not present significant new circumstances or information relevant to environmental concerns and bearing on the impacts of DOE's salt processing and waste disposal program. Therefore, DOE does not need to undertake additional NEPA analysis, and DOE will implement Interim Salt Processing followed by High Capacity Salt Processing through SWPF using the CSSX technology to relieve tank space limitations and assure that vitrification of the high-activity fraction of liquid radioactive waste (sludge waste) at the Savannah River Site will continue uninterrupted while construction of the SWPF is completed.