SUPPLEMENTARY INFORMATION:

I. Background

The NRC is making available to the public the “Environmental Assessment for Proposed License Amendment for Use of Flocculant in the High-Pressure Slurry Ablation Process.” The NRC is also developing a separate Safety Evaluation Report.

II. Introduction

The NRC is considering the approval of a license amendment that would authorize DISA to use flocculant in its HPSA process. DISA specifically requests to use solid FLOPAM, a specific formulation of APAM, a synthetic, water-soluble polymer that is used primarily to pull suspended particles out of liquids through a process called flocculation. Solid APAMs such as FLOPAM are used in applications such as mining and mineral processing, wastewater treatment, and in land applications such as agriculture to improve irrigation and control soil erosion. DISA's license authorizes operation of the HPSA process on AUM waste, which results in the concentration of source material (uranium and thorium) for authorized storage and disposition (ADAMS Accession No. ML26008A090). Using a solid APAM such as FLOPAM in the HPSA process would improve the separation of solid materials from process water after the materials have passed through the HPSA unit.

As required by section 51.21 of title 10 of the Code of Federal Regulations (10 CFR), “Criteria for and identification of licensing and regulatory actions requiring environmental assessments,” the NRC has prepared an EA documenting its evaluation. The NRC concluded that the proposed license amendment would have no significant impact if conditions and proposed operations at each site are consistent with the potential impacts and assumptions detailed in the generic EA, which supplements the NRC's 2025 generic EA for license issuance (ADAMS Accession No. ML25265A212). The NRC will review information submitted by DISA for each site against the generic EA and the 2025 generic EA to determine what areas may require site-specific environmental impact analysis.

A summary of the generic EA follows. Based on the results of the EA, the NRC has determined not to prepare an environmental impact statement for the license amendment and is issuing a FONSI.

III. Summary of the Generic Environmental Assessment

Description of the Proposed Action

The proposed action is a license amendment to allow DISA to use FLOPAM, a specific APAM formulation, in the HPSA process. DISA would need to identify any use of an alternative formulation of flocculant in the site-specific premobilization notification (PMN) for NRC review. The NRC's EA assesses the impacts of using specifically solid form FLOPAM and similar APAMs, and therefore any use of non-solid APAM or non-APAM flocculants would require additional environmental review.

DISA found through testing that FLOPAM would improve the separation of solid materials from water after materials have passed through the HPSA unit. The improvement in separation would result in increasing the concentration of uranium and thorium in the fines concentrates. DISA would add FLOPAM to the fines concentrates during a thickener stage that would occur after the fines concentrates are separated from the coarse material. From the thickener stage, the clumped fines concentrates would flow to a filter press for dewatering, where process water would be recycled. DISA proposes to add ( printed page 45841) approximately 150 grams (about five ounces) of FLOPAM per ton of fines concentrates.

The NRC staff expects that most of the FLOPAM would be sorbed onto the fines concentrates or removed from process water via DISA's water treatment system. Residual quantities of FLOPAM would likely remain dissolved in the process water and would recirculate throughout the HPSA system as the process water is reused. The NRC staff conservatively assumes that FLOPAM concentrations in recirculating water would be less than 10 milligrams per liter (mg/L), a concentration that is comparable to concentrations applied to agricultural fields to improve irrigation.

The NRC staff has determined that recirculation of residual FLOPAM and similar APAMs through the HPSA system could mechanically degrade the APAM's chemical structure, leading to the formation of acrylamide monomer (AMD) in trace amounts. AMD has been found to break down within hours to weeks.

The Need for the Proposed Action

The purpose of the proposed action is to enable DISA to more effectively concentrate uranium and thorium in the fines concentrates that result from the HPSA process, thus also removing these materials more effectively from the process water and coarse material. Since the coarse material and process water would be deposited on the ground after the HPSA processing is complete, improving the removal of uranium and thorium would reduce the amount of these radionuclides that are deposited back onto the ground surface.

Environmental Impacts of the Proposed Action

The NRC staff developed a generic assessment of the potential environmental impacts of using FLOPAM and similarly formulated solid APAMs in the HPSA process. The NRC staff determined that this change in the HPSA process would not affect the NRC's evaluation in the 2025 generic EA of the following resource areas: land use, transportation, geologic resources, air quality, noise, historic and cultural resources, visual and scenic resources, socioeconomics, and public health.

The NRC staff determined that the proposed action would not have significant impacts on water resources, soils, ecological resources, occupational health and safety, and waste management. Using solid form FLOPAM or APAMs would not change the quantities of coarse material or fines concentrates resulting from the HPSA process. It should increase the concentrations of radionuclides in the fines concentrates, reduce concentrations of radionuclides dissolved in process water, and reduce the concentrations of radionuclides in the coarse material. Discharged process water containing residual solid FLOPAM or similar APAMs and potentially very small quantities of AMD would not have significant impacts to native soils. The NRC staff will conduct site-specific assessments of the impacts of depositing coarse material back on the sites, including the presence of trace quantities of APAM and AMD in the coarse material.

The NRC staff has determined that the potential impacts of FLOPAM and similar solid APAMs use on surface water would not be significant primarily because the staff does not expect discharges to surface waters. Further, solid APAMs are widely used in land applications and has been found to be nontoxic, only residual quantities would remain in process water (less than concentrations used in agriculture), and DISA would need to ensure compliance with applicable standards for discharges to the ground surface. The NRC staff expects that the amount of FLOPAM remaining in process water discharged to the ground would be less than 10 mg/L, which is comparable to amounts of FLOPAM and similar solid APAMs used in agriculture. Any trace quantities of AMD contained in the process water discharges are likely to undergo microbial degradation within hours to weeks.

Solid FLOPAM and similar APAM use is not likely to result in a change to the potential for groundwater impacts as assessed in the NRC's 2025 generic EA. The 2025 EA concluded that proposed HPSA operations would have no impact on groundwater as long as DISA does not disturb native soils below the site water table ( e.g., in areas with shallow aquifers) and does not breach a confining layer.

The NRC staff does not expect that solid APAM use in the concentration proposed would significantly affect ecological resources. FLOPAM is commonly used, does not bioaccumulate, and in the concentrations proposed would not have a negative effect on flora or fauna. Peer-reviewed publications concerning the ecological toxicity, fate, transport, and degradation of solid APAM (such as FLOPAM) indicate that the concentrations at which APAM could have negative effects on studied aquatic organisms are more than 10 times the anticipated concentrations of APAM in HPSA process water that would be discharged onsite (and 10 times the quantities used in agriculture). Process water would be discharged to the ground and not into water bodies. FLOPAM does not bioaccumulate and lethal doses to certain aquatic organisms were found to be greater than 100 mg/L. The primary hazard presented by the use of solid APAMs (such as FLOPAM) is the degradation of APAM polymer to AMD. While AMD is recognized as a harmful substance, published research indicates that AMD biodegrades in oxygenated surface water, soils, shallow groundwater, and aerobic sediments within hours to 30 days. DISA would need to abide by any applicable federal, state, local, or tribal requirements for discharges of process water containing APAM or AMD.

Similarly, FLOPAM and similar solid APAMs use in accordance with the manufacturer's instructions would not have significant effects on worker health. FLOPAM does not have chronic or acute toxicity effects. DISA has used FLOPAM in testing processes and has not experienced issues related to worker health and safety.

The use of FLOPAM and similar solid APAMs would not generate a separate waste stream. The solid APAM used in the HPSA process would end up in existing streams: the fines concentrates, process water, water treatment media (filters), and coarse material, as discussed above and in the generic EA. Therefore, solid APAM use would not have significant effects on waste management.

Before mobilizing to a site, DISA would provide site-specific information to the NRC in a PMN, which the NRC staff would review to determine whether the conclusions and assumptions in the generic EA and in the 2025 generic EA apply for that site. If any site conditions, proposed operations, or potential impacts are not consistent with the impacts and assumptions in the EAs, the NRC staff would assess whether further analysis is needed.

Environmental Impacts of the Alternatives to the Proposed Action

As an alternative to the proposed license amendment, the NRC considered the no-action alternative. Under the no-action alternative, the NRC would not amend the license and DISA would not be allowed to use FLOPAM in its HPSA process. If the NRC does not amend DISA's license to allow use of FLOPAM or a similar solid APAMs in HPSA operations, DISA would need to identify another way to improve the separation of uranium-bearing solids from the process water. The potential ( printed page 45842) environmental impacts of the no-action alternative would depend on the nature of an alternative separation method. Alternatively, DISA might choose not to operate HPSA, and section 2.2 of the 2025 generic EA describes other site remediation activities that could occur at the AUM waste sites.

Agencies and Persons Consulted

The NRC provided a draft of this EA for awareness to the 14 states identified by DISA for potential HPSA operations. The final EA will be sent to the U.S. Environmental Protection Agency, the 14 states, Federally recognized Indian tribes, and DISA.

The proposed action is a license amendment that itself has no potential to affect threatened or endangered species under the Endangered Species Act (ESA). Upon receiving the site-specific PMNs, the NRC will assess the potential effects of HPSA operations on threatened and endangered species at each site, and the need for consultation under Section 7 of the ESA for each site. The NRC staff's National Historic Preservation Act (NHPA) Section 106 responsibilities are complete for the licensing undertaking according to section 800.3(a)(1) title 36 of the Code of Federal Regulations, which states: “If the undertaking is a type of activity that does not have the potential to cause effects on historic properties, assuming such historic properties were present, the agency official has no further obligations under Section 106 or this part.” The NRC's consultation and assessment of the potential effects of HPSA operations on cultural and historic properties would occur when specific sites are identified.

IV. Finding of No Significant Impact

Based on its review, in accordance with the requirements of 10 CFR part 51, the NRC has determined that granting the license amendment would not significantly affect the quality of the human environment at a specific site if the site conditions, proposed operations, and potential impacts at the site are consistent with the assumptions and potential impacts assessed in this EA and in the 2025 generic EA. In accordance with 10 CFR 51.31, the NRC concludes that the proposed action does not warrant the preparation of an environmental impact statement, and, pursuant to 10 CFR 51.32, a FONSI is appropriate. If the PMN indicates there are differences in site conditions, proposed operations, or potential impacts, the NRC will evaluate whether these differences require further analysis. If DISA proposes to use a flocculant other than FLOPAM, DISA will need to include this information in the PMN and the NRC staff will determine whether additional environmental review is needed. Subject to confirmation of site-specific conditions and upon the successful conclusion of site-specific consultation under Section 106 of the NHPA, the NRC staff concludes that the proposed HPSA operations with the use of FLOPAM or other similar solid APAMs will not have significant impacts on historic and cultural resources at AUM waste sites. Subject to confirmation of site-specific conditions and upon the successful conclusion of site-specific consultation under Section 7 of the ESA, the NRC staff also concludes that the proposed HPSA operations with the use of FLOPAM or other similar solid APAMs will have no effect or would not be likely to adversely affect any Federally listed threatened or endangered species.

Authority:42 U.S.C. 2011 et seq.

91 FR 45840