Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings

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Federal Register › Vol. 82 › 82 FR 7400

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ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 192 [EPA-HQ-OAR-2012-0788; FRL-9958-12-OAR] RIN 2060-AP43 Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The U.S. Environmental Protection Agency (EPA) is proposing new health and environmental protection standards under the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978. The standards proposed in this action would be applicable to byproduct materials produced by uranium in-situ recovery (ISR) and would be implemented by the U.S. Nuclear Regulatory Commission (NRC) and NRC Agreement States. The EPA initially proposed new health and environmental protection standards for ISR facilities on January 26, 2015; however, the EPA has decided to re-propose the rule and seek additional public to comment on changes to the original proposal, including changes in the regulatory framework and approach, based on public comment and new information received from stakeholders.

The first standards for uranium recovery were issued by the EPA in 1983 when conventional mining and milling were the predominant methods of uranium extraction, and were last amended in 1995. Since the early 1990s, ISR has mostly replaced conventional milling. This proposed rule would strengthen the existing regulations for uranium recovery by adopting new standards addressing groundwater hazards specific to ISR facilities. As with the original proposal, the primary focus of this proposal is groundwater protection, restoration and long-term stability

ion, and were last amended in 1995. Since the early 1990s, ISR has mostly replaced conventional milling. This proposed rule would strengthen the existing regulations for uranium recovery by adopting new standards addressing groundwater hazards specific to ISR facilities. As with the original proposal, the primary focus of this proposal is groundwater protection, restoration and long-term stability.

The most significant changes from the original proposal include: Removing the default 30-year long-term monitoring provision and shifting to a Resource Conservation and Recovery Act (RCRA) Subtitle C corrective action framework as a model rather than a RCRA Subtitle C landfill framework; adding specific criteria and procedures for approving termination of long-term stability monitoring; deleting gross alpha particle activity from proposed Table 1 to subpart F of 40 CFR part 192, and allowing more flexibility for the NRC or Agreement States to determine on a site-specific basis the constituents for which concentration based standards are set. The EPA has also sought to clarify how these standards under UMTRCA complement, and do not overlap with, the requirements of the Safe Drinking Water Act (SDWA).

This action also proposes amendments to certain provisions of the existing rule to address a ruling of the Tenth Circuit Court of Appeals, to update a cross-reference to another environmental standard and to correct certain technical and typographical errors. The proposed rule has been informed by input from the NRC, the U.S. Department of Energy (DOE), states, tribes, industry, environmental groups and other stakeholders, and would promote public health and protect groundwater by reducing the potential for groundwater contamination after production has ceased, and in aquifers adjacent to ISR facilities during uranium recovery.

DATES:

Comments must be received on or before July 18, 2017.

ADDRESSES:

Submit your comments, identified by Docket ID No

es, industry, environmental groups and other stakeholders, and would promote public health and protect groundwater by reducing the potential for groundwater contamination after production has ceased, and in aquifers adjacent to ISR facilities during uranium recovery.

DATES:

Comments must be received on or before July 18, 2017.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2012-0788, by one of the following methods:

• www.regulations.gov: Follow the on-line instructions for submitting comments.

• Email: a-and-r-docket@epa.gov.

• Fax: (202) 566-9744.

• Mail: Air and Radiation Docket, Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave. NW., Washington, DC 20460.

• Hand Delivery: EPA West Building, Room 3334, 1301 Constitution Ave. NW., Washington, DC 20004. Such deliveries are only accepted during the Docket's normal hours of operation; special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-2012-0788. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through www.regulations.gov or email. The www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet

an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about the EPA's public docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.

Docket: All documents in the docket are listed in the www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy at the Office of Air and Radiation Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air and Radiation Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

Ingrid Rosencrantz, Office of Radiation and Indoor Air, Radiation Protection Division, Mailcode 6608T, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave

p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air and Radiation Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

Ingrid Rosencrantz, Office of Radiation and Indoor Air, Radiation Protection Division, Mailcode 6608T, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave. NW., Washington, DC 20460; telephone number: (202) 343-9286; fax number: (202) 343-2304; email address: Rosencrantz.ingrid@epa.gov.

SUPPLEMENTARY INFORMATION:

A. Does this action apply to me?

The regulated categories and entities potentially affected by the proposed standards include:

Category NAICS code 1 Examples of regulated entities Industry: Uranium Ores Mining and/or Beneficiating 212291 Facilities that extract or concentrate uranium from any ore processed primarily for its source material content. Leaching of Uranium, Radium or Vanadium Ores 212291 Facilities that extract or concentrate uranium from any ore processed primarily for its source material content. 1 North American Industry Classification System. This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this proposed action.

B. What should I consider as I prepare my comments to EPA?

Submitting CBI. Do not submit CBI information to the EPA through www.regulations.gov or email. Clearly mark the part or all of the information that you claim to be CBI. For CBI information contained on a disk or CD ROM that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket

that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information marked as CBI will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

Tips for preparing your comments. When submitting comments, remember to:

• Identify the rulemaking by docket number and other identifying information (subject heading, Federal Register date and page number).

• Follow directions—The agency may ask you to respond to specific questions or organize comments by referencing a Code of Federal Regulations (CFR) part or section number.

• Explain why you agree or disagree, suggest alternatives, and substitute language for your requested changes.

• Describe any assumptions and provide any technical information and/or data that you used.

• If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced.

• Provide specific examples to illustrate your concerns, and suggest alternatives.

• Explain your views as clearly as possible, avoiding the use of profanity or personal threats.

• Submit your comments by the comment period deadline.

C. When would a public hearing occur?

If anyone contacts the EPA requesting to speak at a public hearing concerning this proposed rule by February 21, 2017, the EPA will hold a public hearing. If you are interested in attending a public hearing, contact Mr. Anthony Nesky at (202) 343-9597. If a public hearing is held, the Agency will announce the date, time and venue on the EPA Web site at http://www.epa.gov/radiation/tenorm/40CFR192.html.

contacts the EPA requesting to speak at a public hearing concerning this proposed rule by February 21, 2017, the EPA will hold a public hearing. If you are interested in attending a public hearing, contact Mr. Anthony Nesky at (202) 343-9597. If a public hearing is held, the Agency will announce the date, time and venue on the EPA Web site at http://www.epa.gov/radiation/tenorm/40CFR192.html.

D. What documents are referenced in today's proposal?

The EPA refers to a number of documents that provide supporting information for the Agency's proposed uranium and thorium mill tailings standards. All documents relied upon by the EPA in regulatory decision making may be found in the EPA docket (EPA-HQ-OAR-2012-0788) accessible via http://www.regulations.gov/. Other documents ( e.g., statutes, regulations, and proposed rules) are readily available from public sources. The EPA documents listed below are referenced most frequently in today's proposal.

EPA 402/D-14-001, “Considerations Related to Post Closure Monitoring of Uranium In-Situ Leach/In-Situ Recovery (ISL/ISR) Sites,” EPA, 2014.

EPA 402/R-14-003, “Economic Analysis: Proposed Revisions to the Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings Rule (40 CFR part 192),” EPA, 2016.

EPA 530/R-09-007, “Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities—Unified Guidance,” EPA, 2009.

E. Preamble Abbreviations

The following abbreviations are used in this preamble:

this preamble:

ACL Alternate concentration limit AEA Atomic Energy Act BID Background information document CFR Code of Federal Regulations COOs Civilian owners and operators DOE Department of Energy EPA U.S. Environmental Protection Agency FR Federal Register ISR In-situ recovery, also known as in-situ leaching (ISL) MCL Maximum contaminant level NRC U.S. Nuclear Regulatory Commission NUREG U.S. Nuclear Regulatory Commission Guides OMB Office of Management and Budget RAC Radiation Advisory Committee RCRA Resource Conservation and Recovery Act RFA Regulatory Flexibility Act SAB Science Advisory Board SDWA Safe Drinking Water Act UCL Upper control limit UIC Underground injection control U.S. United States UMRA Unfunded Mandates Reform Act of 1995 UMTRCA Uranium Mill Tailings Radiation Control Act of 1978 U.S.C. United States Code USDW Underground source of drinking water F. Organization of This Document

The information presented in this preamble is organized as follows: I. Executive Summary A. Background B. Purpose of the Regulatory Action C. Summary of the Major Provisions D. Summary of the Costs and Benefits E. Statutory Authority for This Action II. Summary of the Proposed Rule A. Proposed Standards for Uranium ISR Operations B. Amendments to 40 CFR Part 192, Subparts C and D III. Summary of Changes Made to the Original Proposal and Rationale for Those Changes A. Incorporation of the Initial and Long-Term Stability Standards in Proposed 40 CFR 192.52 B. Groundwater Protection Standards C. Preoperational Monitoring Requirements D. Exempted Aquifers E. Excursions F. Initial and Long-Term Stability G. Corrective Action Program H. Costs and Economic Impacts I. Other Miscellaneous Changes IV. Responses to Other Significant Comments That Did Not Result in Changes to the Original Proposal A. Authority To Set and Enforce Standards B. Need for New Standards for Uranium ISR Facilities C. Applicability D. The 95 Percent Confidence Level V. Summary of Environmental, Cost and Economic Impacts A

bility G. Corrective Action Program H. Costs and Economic Impacts I. Other Miscellaneous Changes IV. Responses to Other Significant Comments That Did Not Result in Changes to the Original Proposal A. Authority To Set and Enforce Standards B. Need for New Standards for Uranium ISR Facilities C. Applicability D. The 95 Percent Confidence Level V. Summary of Environmental, Cost and Economic Impacts A. Environmental Impacts of the Proposed Rule on Groundwater Quality B. Incremental Costs of Complying With the Proposed Rule C. Economic Impacts of the Proposed Rule on the Market for Uranium and the Uranium Industry D. Benefits of the Proposed Rule VI. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review B. Paperwork Reduction Act C. Regulatory Flexibility Act D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution or Use I. National Technology Transfer Advancement Act J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations I. Executive Summary

A. Background

ISR is a method by which uranium is leached from underground ore bodies by the introduction of a solvent solution, called a lixiviant, through injection wells drilled into the ore zone. The process does not require excavation to extract the ore body from the ground or conventional milling to extract the uranium from the mined ore. After the lixiviant is injected underground, it passes through the ore zone and mobilizes the uranium. The uranium-bearing solution is then pumped to the surface via extraction wells, and the solution is processed to extract the uranium

to the ore zone. The process does not require excavation to extract the ore body from the ground or conventional milling to extract the uranium from the mined ore. After the lixiviant is injected underground, it passes through the ore zone and mobilizes the uranium. The uranium-bearing solution is then pumped to the surface via extraction wells, and the solution is processed to extract the uranium. During uranium production, the fluids injected to mobilize uranium change the chemistry of the aquifer from its original state, thereby mobilizing uranium and many other minerals and metals. Groundwater from the ISR production zone can migrate from the production zone and contaminate nearby groundwater with arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, nitrate, molybdenum, radium and uranium and other constituents. The standards proposed in this action would minimize the risk of undetected groundwater degradation and constituent migration during and after ISR operations have ceased.

The EPA initially proposed new health and environmental protection standards for ISR facilities on January 26, 2015 (hereinafter “original proposal”), with the intention of finalizing the new standards in 2016. 1 During the public comment period, the Agency received over 5,380 public comment letters from a wide range of stakeholders, with comments covering more than 80 different topics. In addition, during interagency review, more than 15 groups of stakeholders met with Office of Management and Budget (OMB) to voice comments on the original proposal. Commenters were particularly concerned about the default 30-year long-term monitoring requirement, felt that the optional method by which a licensee could request permission to cease long-term stability monitoring lacked sufficient specificity and believed the number of constituents required to be monitored was unreasonably burdensome

nt and Budget (OMB) to voice comments on the original proposal. Commenters were particularly concerned about the default 30-year long-term monitoring requirement, felt that the optional method by which a licensee could request permission to cease long-term stability monitoring lacked sufficient specificity and believed the number of constituents required to be monitored was unreasonably burdensome. Several commenters thought the economic analysis underestimated the compliance costs and identified several additional categories of costs related to the long-term monitoring requirements they felt had been omitted from the analysis or were not representative of the actual costs incurred. Other commenters felt that several additional types of benefits should be included in the benefits analysis. After consulting with the NRC and other agencies and collecting additional information from industry, including participation in stakeholder meetings during interagency review with OMB, the EPA decided to make several changes to the original proposal and solicit additional public comment rather than finalize the rule with the changes. These changes are described in detail in section III of this preamble. The most significant changes include removing the default 30-year long-term monitoring provision and shifting to more of a RCRA Subtitle C corrective action framework as a model rather than a RCRA Subtitle C landfill framework, adding specific criteria and procedures for approving termination of long-term stability monitoring, deleting gross alpha particle activity from proposed Table 1 to subpart F, and allowing more flexibility for the NRC and Agreement States (hereinafter “regulatory agency”) to determine on a site-specific basis the constituents for which concentration-based standards are set. The EPA has also sought to clarify how these standards under UMTRCA complement, and do not overlap with, the requirements of the SDWA

gross alpha particle activity from proposed Table 1 to subpart F, and allowing more flexibility for the NRC and Agreement States (hereinafter “regulatory agency”) to determine on a site-specific basis the constituents for which concentration-based standards are set. The EPA has also sought to clarify how these standards under UMTRCA complement, and do not overlap with, the requirements of the SDWA. In addition to these more significant changes, the EPA has also made minor changes to the original proposal, such as moving the initial and long-term monitoring standards to the proposed § 192.52 and moving the requirements for alternate concentration limits (ACLs) to a separate section ( see proposed § 192.54). In addition to making changes to the rule text, the EPA also re-calculated the incremental compliance costs to incorporate estimated non-monitoring costs ( e.g., licensing, leasing fees, continued surety, maintenance) and incorporated additional cost information provided by industry. The EPA re-evaluated the economic and energy impacts to both address the concerns raised by commenters and to incorporate the changes the Agency made to the standards since the original proposal was published. The revised costs and economic analysis for this proposal are discussed in section V of this preamble. While the majority of the changes to the original proposal are relatively minor, the EPA decided it was appropriate to re-propose the rule due to the high level of public interest in this rulemaking. This action provides the public an opportunity to review and provide comment on the changes made to the original proposal and allows the EPA to consider and make any additional changes based on those comments before finalizing the rule. The EPA is requesting comment on all aspects of this proposed action. Because this is a re-proposal, and the EPA wishes to consider comments in context, please re-submit any relevant comments that may have been submitted on the original proposal.

1 See 80 FR 4156, January 26, 2015

l and allows the EPA to consider and make any additional changes based on those comments before finalizing the rule. The EPA is requesting comment on all aspects of this proposed action. Because this is a re-proposal, and the EPA wishes to consider comments in context, please re-submit any relevant comments that may have been submitted on the original proposal.

1 See 80 FR 4156, January 26, 2015.

Several commenters also voiced concerns about information and data collection, including review of Agreement State regulatory programs that address ISRs. Although the EPA requested and collected data and information as outlined in section IV.B of this preamble, the Agency understands stakeholders concerns and are inviting stakeholders to submit additional data and analyses to further clarify the ISR process, including any additional monitoring results and analyses. The EPA will be collecting additional information on state regulatory programs, as recommended by several states.

B. Purpose of the Regulatory Action

The EPA is proposing to add new health and environmental protection standards to regulations promulgated under UMTRCA. The proposed standards would regulate byproduct materials produced by ISR, including both surface and groundwater standards, with a primary focus on groundwater protection, restoration and stability. By explicitly addressing the most significant environmental and public health hazards presented by ISR activities, these proposed standards would address the shift toward ISR as the dominant form of uranium recovery that has occurred since the standards for

This rule would provide the necessary framework for consistent and sustainable protection of groundwater at ISR sites that will continue to have beneficial uses even if the aquifer has been exempted from protection under the SDWA

sented by ISR activities, these proposed standards would address the shift toward ISR as the dominant form of uranium recovery that has occurred since the standards for

Groundwater is a scarce resource that is under increasing pressure, particularly in the arid West where groundwater has multiple uses, including for livestock production, crop irrigation, wildlife support, and human consumption. As groundwater resources are depleted, it becomes even more important to preserve those resources for future uses. Stakeholders in these areas are already finding a need to use groundwater that is of lower quality than desired. 2 Groundwater that contains mineral resources, such as uranium, is not necessarily of such poor quality that it cannot be used for these purposes. By altering the chemical composition of groundwater, ISR creates reasons to be concerned about impacts to groundwater, which may be used for human drinking water, as well as for other purposes, such as livestock watering, crop irrigation and wildlife support.

2 Application for Amendment of USNRC Source Materials License SUA-1601, Ross ISR Project, Kendrick Expansion Area, Crook County, Wyoming Docket #40-9091, 2015. pp. 3-100; USGS National Brackish Groundwater Information Sheet 2013; Advanced Treatment for Groundwater, Treating Low Quality Groundwater for Municipal Use, Water Engineering and Management, Nov. 2001.

While an aquifer or portions of an aquifer may have been exempted from the protections of the SDWA, the aquifer may be needed in the future for human drinking water or other purposes

-9091, 2015. pp. 3-100; USGS National Brackish Groundwater Information Sheet 2013; Advanced Treatment for Groundwater, Treating Low Quality Groundwater for Municipal Use, Water Engineering and Management, Nov. 2001.

While an aquifer or portions of an aquifer may have been exempted from the protections of the SDWA, the aquifer may be needed in the future for human drinking water or other purposes. The standards proposed in this action do not require licensees to improve groundwater quality, only to provide confidence that: (1) In the area mined, the applicable constituent concentration standards (set at either background or health-based levels, whichever is higher), are met and remain stable; and (2) that uranium recovery operations will not endanger adjacent aquifers. EPA requests comment on whether groundwater, once it meets the constituent concentration standards, could or would potentially be used for drinking water or other purposes.

UMTRCA directs the EPA to establish standards of general application, while the NRC is vested with implementing the EPA's standards under its licensing and enforcement authority. The EPA has previously promulgated general standards under UMTRCA for surface disposal of mill tailings from conventional uranium mining and milling, but ISR has become the dominant form of uranium extraction since the 1990s. In 2006, an NRC commissioner observed that ISR-specific rules were needed to provide a national approach to bring predictability to the industry and state regulators. This view was not predicated on specific documented instances of groundwater contamination outside of the ISR production zone. The scope and level of protection of the SDWA differs from the UMTRCA. The purpose of the SDWA UIC program is to prevent endangerment of underground sources of drinking water. In determining whether an aquifer may be exempted from the protection of the SDWA, the EPA does not consider its use for purposes other than human drinking water ( e.g. agriculture and other uses)

of the ISR production zone. The scope and level of protection of the SDWA differs from the UMTRCA. The purpose of the SDWA UIC program is to prevent endangerment of underground sources of drinking water. In determining whether an aquifer may be exempted from the protection of the SDWA, the EPA does not consider its use for purposes other than human drinking water ( e.g. agriculture and other uses).

As the highlighted portions of the SDWA regulations below show, there is no requirement to demonstrate poor water quality prior to issuing an aquifer exemption if the aquifer is or could be mineral producing. Under the SDWA's UIC regulations, aquifer exemptions are used to allow for mineral recovery in aquifers that would otherwise be protected as sources of drinking water when certain criteria are met. In the SDWA regulations, § 146.4 provides that: “An aquifer or a portion thereof which meets the criteria for an “underground source of drinking water” in § 146.3 may be determined under § 144.7 of this chapter to be an “exempted aquifer” for Class I-V wells if it meets the criteria in paragraphs (a) through (c) of this section. Class VI wells must meet the criteria under paragraph (d) of this section: (a) It does not currently serve as a source of drinking water; and (b) It cannot now and will not in the future serve as a source of drinking water because: (1) It is mineral, hydrocarbon or geothermal energy producing, or can be demonstrated by a permit applicant as part of a permit application for a Class II or III operation to contain minerals or hydrocarbons that considering their quantity and location are expected to be commercially producible; or (2) It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical; or (3) It is so contaminated that it would be economically or technologically impractical to render that water fit for human consumption; or (4) It is located over a Class III well mining area subject to subsidence or catastrophi

mmercially producible; or (2) It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical; or (3) It is so contaminated that it would be economically or technologically impractical to render that water fit for human consumption; or (4) It is located over a Class III well mining area subject to subsidence or catastrophic collapse; or (5) The total dissolved solids content of the ground water is more than 3,000 and less than 10,000 mg/l and it is not reasonably expected to supply a public water system . . .”.

In addition, although a portion of an aquifer may be exempted from the protections of the SDWA, there are no federal requirements preventing recovery and use of the water within exempted aquifers (including where ISR operations were previously conducted) for private drinking water supply, public water supply, or other uses.

UMTRCA provides authority that can be used to protect aquifers during and after uranium recovery operations, regardless of whether the aquifer meets the definition of an underground source of drinking water (USDW) as defined in the EPA's UIC regulations or is exempted from the protections of the SDWA because it meets the existing regulatory criteria for exemption. UMTRCA directs the Administrator to promulgate “standards of general application for the protection of public health, safety, and the environment from radiological and non-radiological hazards associated with the processing, and possession, transfer, and disposal of byproduct material”. 3 The statute further provides that “[i]n establishing such standards, the Administrator shall consider the risk to the public health, safety, and the environment, the economic costs of applying such standards, and such other factors as the administrator determines to be appropriate”. 4

3 See 42 U.S.C. 2022(b)(1).

4 Ibid

rocessing, and possession, transfer, and disposal of byproduct material”. 3 The statute further provides that “[i]n establishing such standards, the Administrator shall consider the risk to the public health, safety, and the environment, the economic costs of applying such standards, and such other factors as the administrator determines to be appropriate”. 4

3 See 42 U.S.C. 2022(b)(1).

4 Ibid.

In areas being mined for uranium, the SDWA does not require operators or regulators to collect the level of data needed to definitively confirm or disprove drinking water contamination or contamination of water for other purposes that may also impact humans, such as livestock watering and crop irrigation. Additionally, data that the EPA's UIC Program have received and evaluated at or near at least one ISR facility are consistent with an excursion beyond the boundary of the exempt aquifer ( i.e., leading to elevated uranium levels outside the ISR facility area).

The proposed 40 CFR part 192, subpart F would afford protections that do not currently exist under federal UIC regulations and would be complementary to existing regulations ( e.g., UIC regulations) at uranium ISR facilities. For example, these new provisions proposed under the authority of UMTRCA would address corrective action, broad baseline development, monitoring well placement and aquifer restoration. The proposed provisions would also provide assurance that once

The proposed 40 CFR part 192, subpart F also would ensure that industry maintains responsibility for protection of public health and the environment at uranium ISR facilities during and after uranium recovery operations.

sponsibility for protection of public health and the environment at uranium ISR facilities during and after uranium recovery operations.

Since ISR alters the chemical composition of groundwater, it creates reasons to be concerned about risk to public health, safety and the environment from radiological and non-radiological hazards associated with the processing and disposal of byproduct material. Industry commenters and others say that there is no need for this rule because the EPA has not identified an instance in which an ISR operation has contaminated a source of drinking water. First, the Agency notes that this proposal addresses groundwater protection at ISR facilities both in and around the production zone and in surrounding aquifers. Focusing on the area of surrounding or adjacent aquifers, the EPA acknowledges that the Agency does not have sufficient information to document a specific instance of contamination of a public source of drinking water caused by an ISR. The Agency remains concerned, however, that the available data may not be capturing some instances of contamination that this proposed rule seeks to prevent. In other words, the Agency remains concerned that the lack of data does not demonstrate that no contamination is occurring, as industry commenters assert, but instead merely demonstrates the lack of data available to be able to make such a determination, especially where there has been limited post-restoration monitoring. The monitoring requirements in this proposal address the issue of lack of data.

As explained in this preamble, in documents supporting this proposal, and as included in the docket for this proposal, there is ample evidence of excursions occurring as the result of ISR facilities. For example, data that the EPA's UIC Program have received and evaluated at or near at least one ISR facility are consistent with an excursion beyond the boundary of the exempt aquifer, leading to elevated uranium levels outside the ISR facility

upporting this proposal, and as included in the docket for this proposal, there is ample evidence of excursions occurring as the result of ISR facilities. For example, data that the EPA's UIC Program have received and evaluated at or near at least one ISR facility are consistent with an excursion beyond the boundary of the exempt aquifer, leading to elevated uranium levels outside the ISR facility. In addition, there is data in the proposal's Background Information Document (BID) describing numerous excursions from several ISR facilities. Moreover, data in attachment 5 of the BID shows that several ISR facilities have not met background or health-based levels after restoration of the production zone. This data, when considered with the understanding that groundwater flow is often extremely slow, raises concerns that there has been insufficient monitoring conducted by these ISR facilities to identify the actual contamination that may be occurring or may occur in the future beyond the production zone and in sources of drinking water. The EPA solicits comment on industry's assertion that in no case have any excursions from ISR facilities resulted in contamination in aquifers being used as public sources of drinking water or for other uses. In addition, the EPA also requests comment on the kinds of data that would be needed to clearly link ISR operations with off-site contamination or that would support claims that there is no contamination of concern.

The EPA notes that several NRC-regulated ISR facilities are continuing to work toward restoring groundwater, with restoration and monitoring being conducted for as long as 10 years after ceasing production. The Agency understands that restoration does not always meet original background levels as evidenced by the number of restoration goals exceeding background or the levels proposed in Table 1 to subpart F

tes that several NRC-regulated ISR facilities are continuing to work toward restoring groundwater, with restoration and monitoring being conducted for as long as 10 years after ceasing production. The Agency understands that restoration does not always meet original background levels as evidenced by the number of restoration goals exceeding background or the levels proposed in Table 1 to subpart F. Additionally, the NRC acknowledges that efficiency could be gained by codifying its longstanding effective regulatory regime into regulations specific to ISR facilities. Historically, restoration and monitoring at ISR facilities are typically conducted for only a short period, and a longer period would provide more confidence to demonstrate that restoration of the affected groundwater is complete and that long-term stability is established with confidence before license termination. The initial and long-term stability monitoring and corrective action program included in this proposal would ensure that both of these requirements are met before ISR facilities can be decommissioned.

At ISR facilities, the groundwater is directly impacted by the injection of lixiviant into the aquifer, which alters the geochemistry of the ore-bearing formation and increases the concentration of radionuclides and other metals in the water. Restoration activities attempt to restore the water quality for specific constituents to the applicable constituent concentration standards inside the production zone. Although subpart D to 40 CFR part 192 (hereinafter “subpart D”) addresses contamination of aquifers, it explicitly addresses only contamination resulting from releases from uranium mill tailings impoundments used to store uranium byproduct material ( e.g., conventional tailings impoundments, evaporation or holding ponds)

he applicable constituent concentration standards inside the production zone. Although subpart D to 40 CFR part 192 (hereinafter “subpart D”) addresses contamination of aquifers, it explicitly addresses only contamination resulting from releases from uranium mill tailings impoundments used to store uranium byproduct material ( e.g., conventional tailings impoundments, evaporation or holding ponds). Under the proposed subpart F, the licensee is required to restore groundwater in the production zone and surrounding aquifers to the applicable constituent concentration standards, to the extent possible, and to show some level of stability in the production zone prior to terminating the license. Because ISR changes the geochemistry of the groundwater, more rigorous stability-based standards together with corrective action programs are necessary to ensure that the production zone is restored and the applicable constituent concentration standards will continue to be met in the future.

As described in the preamble to the 2015 proposal, the EPA solicited technical advice on key issues related to groundwater protection at ISR sites from the Radiation Advisory Committee (RAC) of the Agency's Science Advisory Board (SAB) (80 FR 156). The final report of the SAB/RAC, along with the EPA's response, can be found at: https://yosemite.epa.gov/sab/sabproduct.nsf/c91996cd39a82f648525742400690127/0314cef928df63cc8525775200482fa3!OpenDocument&TableRow=2.4#2.

The SAB/RAC further considered this issue in 2015, and the Agency provided a detailed cross-walk to the 2015 proposed rule to show how the RAC's advice had been addressed. The SAB determined that no further action was needed on its part. See https://yosemite.epa.gov/sab/sabproduct.nsf/02ad90b136fc21ef85256eba00436459/8DA59AB1BE0EA14B85257E660071F2EF/$File/EPA-SAB-15-009+unsigned.pdf. In general, the BID addresses topics specifically addressed by the RAC as follows:

The EPA has evaluated available data for all phases of ISR activities to address the SAB recommendations

SAB determined that no further action was needed on its part. See https://yosemite.epa.gov/sab/sabproduct.nsf/02ad90b136fc21ef85256eba00436459/8DA59AB1BE0EA14B85257E660071F2EF/$File/EPA-SAB-15-009+unsigned.pdf. In general, the BID addresses topics specifically addressed by the RAC as follows:

The EPA has evaluated available data for all phases of ISR activities to address the SAB recommendations. Section 5 of the BID analyzes data and examines specific case studies for baseline and restoration, with particular attention given to establishment of baseline at the Dewey-Burdock site in South Dakota (Attachment A). Sections 6 and 7.8 and Attachment F provide extensive analysis of post-restoration monitoring at the Crow Butte, Christensen, Highland, and Irigaray ISR sites, including regression analysis and statistical testing, and cumulative complementary distribution functions (CCDF). Results are presented by analyte, mine unit, and well.

Section 6 addresses in detail SAB recommendations related to influences on groundwater chemistry and their effects on time frames for stability

This action also proposes amendments to certain provisions in the current rule, located at 40 CFR part 192. Specifically, this action addresses a ruling of the Tenth Circuit Court of Appeals, updates a cross-reference to another environmental standard and corrects other technical and typographical errors.

C. Summary of the Major Provisions

The proposed rule includes a new subpart, subpart F, within 40 CFR part 192, which sets standards to protect groundwater at uranium ISR operations. Specifically, subpart F would set standards of general application to protect groundwater beyond the production zone during ISR operational and restoration phases and to ensure, once the wellfield is restored, that the restoration is complete and stable. The proposed rule includes three types of groundwater protection standards: (1) Constituent concentration standards, (2) initial stability standards, and (3) long-term stability standards

s of general application to protect groundwater beyond the production zone during ISR operational and restoration phases and to ensure, once the wellfield is restored, that the restoration is complete and stable. The proposed rule includes three types of groundwater protection standards: (1) Constituent concentration standards, (2) initial stability standards, and (3) long-term stability standards. The proposed rule also includes monitoring requirements to establish statistically valid background water quality levels, excursion monitoring (for the operational and restoration phases), and monitoring to meet the initial and long-term stability standards. The proposed rule also includes a requirement to establish a corrective action program. Once finalized, these standards will be implemented by the regulatory agency. Once the regulatory agency incorporates the new standards into its regulations, or takes other appropriate steps to implement the new standards, this will provide a nationally consistent approach for the licensing process for ISR facilities. 5

5 Currently, the process used by the NRC for licensing ISR facilities is based on a combination of NRC regulations, site-specific license conditions, and guidance. The process used by the Agreement States is based on regulations that vary by state for Agreement States that regulate ISR facilities. The NRC and many of the Agreement States have an established hearing process that allows for interested parties to request a hearing on the merits for the issuance and amendment of ISR facility licenses.

D. Summary of the Costs and Benefits

The costs and benefits of this rulemaking are described briefly in Table 2 of this preamble. The costs reflect the difference in costs that would be incurred by ISR licensees under the proposed rule and costs that would be incurred by those facilities in the absence of the proposed rule. These incremental costs include added costs associated with monitoring and non-monitoring compliance actions under the proposed rule

s of this rulemaking are described briefly in Table 2 of this preamble. The costs reflect the difference in costs that would be incurred by ISR licensees under the proposed rule and costs that would be incurred by those facilities in the absence of the proposed rule. These incremental costs include added costs associated with monitoring and non-monitoring compliance actions under the proposed rule. For additional details on the incremental costs of the proposed rule, see section V.B of this preamble and section 3 of the document titled, “Economic Analysis: Revisions to the Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings Rule (40 CFR part 192),” available in Docket ID No. EPA-HQ-OAR-2012-0788.

Complying with the proposed standards may require some existing ISR facilities to monitor groundwater for additional constituents that they are not currently monitoring. It would also require all ISR facilities to continue monitoring for a period of at least three years after the initial stability standard is met, and to conduct geochemical modeling and other analysis to demonstrate that the applicable constituent concentration standards will continue to be met in the future. The additional monitoring, modeling and analysis that would be required under this proposed rule could increase costs to ISR facilities. The additional years during which ISR facilities' license, surety, insurance, maintenance and other non-monitoring activities would have to be maintained would also increase costs. The EPA estimates the rule imposes annualized incremental costs on the ISR industry of approximately $11.9 million, including incremental monitoring costs and other non-monitoring costs.

s the rule imposes annualized incremental costs on the ISR industry of approximately $11.9 million, including incremental monitoring costs and other non-monitoring costs.

In its economic analysis, the EPA analyzed potential economic impacts of the rule on small entities (7 companies) using a range of assumptions about revenues of firms that own ISR facilities and costs of complying with the rule. The “average revenue” assumption is based on a market price of $55 per pound of U3O8e and production that is 25% of facility capacity. The “low revenue” assumption reflects revenues 10% lower, and the high revenue assumption reflects revenues that would be 20% higher. With average costs, cost-to-sales ratios for small firms range from 0.7% to 3.1% for the low revenue scenario and from 0.5% to 2.3% under the higher revenue scenario. These assumptions are intended to reflect the range of possible market conditions at the time when the rule would take effect (likely 2022 to 2025). Uranium market projections for the longer term are generally optimistic, reflecting growth in nuclear power in China and India and other countries; 57 new reactors are currently under construction with 65% of those projected to come online by 2020, and world-wide electricity consumption is projected to increase by 50% between 2013 and 2035 (only part of the increase is estimated to be met by nuclear energy) (Cameco, 2016). Outlook for the near term, however, is less positive, and the rate of recovery is uncertain.

The EPA acknowledges that current uranium market conditions reflect depressed demand for uranium (due to lingering effects of the Fukushima incident, slow recovery of demand for electricity since the recession and low prices of substitute sources of energy) and some reliance on alternative (non-mine) sources of uranium. As a result, both the price and production of uranium have fallen. The long-term contract price of uranium has declined from around $60 per pound of U3O8e in 2012 to around $40 per pound in 2016

ffects of the Fukushima incident, slow recovery of demand for electricity since the recession and low prices of substitute sources of energy) and some reliance on alternative (non-mine) sources of uranium. As a result, both the price and production of uranium have fallen. The long-term contract price of uranium has declined from around $60 per pound of U3O8e in 2012 to around $40 per pound in 2016. Spot prices have generally been 20% lower than contract prices. While market forces have driven the market price for uranium down by $20 to $30 dollars over the past 5 years, the rule is estimated to increase the cost of producing uranium using ISR methods by between $1.27 per pound U3O8e and $2.45 per pound of U3O8e, depending on the cost scenario.

Because of these market conditions, several ISR facilities that are fully licensed and permitted are not currently producing uranium (including previously operational facilities that have been placed on standby and licensed and permitted facilities that have never gone into production), and development of new ISR facilities has largely been put on hold. Further, several ISR facilities have changed ownership in the past few years, as companies have been forced by market conditions to sell assets. In other words, some ISR firms currently are unable to profitably operate their facilities even in the absence of the rule. Several of the small firms report little or no revenue from sales of uranium. Even the relatively small incremental costs required to comply with the rule's provisions would not currently be affordable for such firms. This is not due to the magnitude of the rule's costs; it is due to current conditions in the world's economy generally and in the market for uranium in particular. The EPA considers that when the market for uranium recovers, as it is projected to do, ISR uranium production and price will increase; under those conditions, facilities that are currently unprofitable without the rule would likely be profitable with the rule's costs included

rule's costs; it is due to current conditions in the world's economy generally and in the market for uranium in particular. The EPA considers that when the market for uranium recovers, as it is projected to do, ISR uranium production and price will increase; under those conditions, facilities that are currently unprofitable without the rule would likely be profitable with the rule's costs included. However, the EPA solicits public

The EPA compared these costs to the potential financial, ecological and human health benefits that would result from the proposed rule. Although the EPA is unable to quantify all the potential benefits, the EPA has identified several categories of benefits that can be attributable to the rule. The proposed rule would require groundwater at ISR facilities to be restored to the constituent concentration standards. Licensees would have to demonstrate stability of groundwater at those constituent concentration standards by completing at least 6 years of monitoring (3 years to meet the initial stability standards plus 3 years to meet the long-term stability standards), and conduct modeling and analysis to demonstrate there is a reasonable assurance that the applicable constituent concentration standards will continue to be met in the future. This provision would minimize the risk of degradation of valuable groundwater resources and the potential exposure of human, domestic livestock or ecological receptors to radiological or other constituents. The proposed rule would also minimize the potential contamination of surface water and potential adverse health impacts resulting from such contamination. In addition, the proposed rule would avoid the potential costs associated with remediating contaminated aquifers; the cost of remediating a single plume of contamination could exceed the nationwide incremental costs associated with the proposed rule

proposed rule would also minimize the potential contamination of surface water and potential adverse health impacts resulting from such contamination. In addition, the proposed rule would avoid the potential costs associated with remediating contaminated aquifers; the cost of remediating a single plume of contamination could exceed the nationwide incremental costs associated with the proposed rule. The EPA estimated the cost savings due to avoided pump and treat remediation for hypothetical contaminant migration examples using the Conceptual Mine Unit, under three plume scenarios. For each scenario, the EPA computed the estimated cost savings by computing the difference in the cost of remediating a large plume (which might result if the plume were not detected for many years) and the cost of remediating a small plume discovered through monitoring prior to facility closure. The total estimated avoided costs over the entire remediation episode in this illustration, remediating three different sized plumes, ranged from $23.7 million to $608 million, depending on the scenario. Annualized, these avoided costs range from $1.5 million to $11.1 million per year. To reflect the recognition that the proposed rule would reduce the likelihood of contamination relative to existing regulatory requirements, but not eliminate it entirely, the EPA further assumed a range of probability that the illustrative example contamination episode would be prevented by the proposed rule, but not identified under current requirements. The EPA assumed that the likelihood that the proposed rule would prevent the contamination, but current requirements would not, would range from 20% to 80%. Thus, the values shown in the table are 20% of the lower bound value ($0.3 million) to 80% of the upper bound value ($8.9 million). However, because the EPA is unable to quantify the number or characteristics of contamination episodes that could occur in the absence of the proposed rule, the EPA is unable to estimate nationwide cost savings

rent requirements would not, would range from 20% to 80%. Thus, the values shown in the table are 20% of the lower bound value ($0.3 million) to 80% of the upper bound value ($8.9 million). However, because the EPA is unable to quantify the number or characteristics of contamination episodes that could occur in the absence of the proposed rule, the EPA is unable to estimate nationwide cost savings. Thus, the EPA has not compared these illustrative costs savings with the estimated national costs of the proposed rule or computed the net benefits.

Table 2—Characterization of the Costs and Benefits of 40 CFR Part 192, Subpart F Incremental costs (2015 dollars) Benefits Annualized costs of monitoring, modeling and analysis ranging from $0.2 to $7.3 million Protection of groundwater quality. Annual non-monitoring costs, including license, surety, lease, maintenance: $7.6 million Possible protection of surface water quality. Potentially reduced risk of exposure of human or ecological receptors to radiological pollutants. Potentially reduced human health impacts, including cancer. Annualized avoided cost of single remediation effort would be between $0.3 million and $8.9 million. 1 1 The costs presented are not an estimate of the nationwide remediation cost savings. They are the estimated cost of remediation for a simplified example of a single wellfield, for three contaminant plume scenarios. E. Statutory Authority for This Action

The EPA is proposing the new standards and amendments under its authority in section 275 of the Atomic Energy Act (AEA), as added by section 206 of UMTRCA

presented are not an estimate of the nationwide remediation cost savings. They are the estimated cost of remediation for a simplified example of a single wellfield, for three contaminant plume scenarios. E. Statutory Authority for This Action

The EPA is proposing the new standards and amendments under its authority in section 275 of the Atomic Energy Act (AEA), as added by section 206 of UMTRCA. 6 Section 206 of UMTRCA authorizes the EPA to promulgate standards of general application for the protection of public health, safety, and the environment from radiological and non-radiological hazards associated with (a) residual radioactive materials located at specifically listed inactive uranium milling sites, nearby contaminated “vicinity properties,” and depository sites for such materials selected by the Secretary of Energy (commonly referred to as Title I sites); and (b) the processing and the possession, transfer and disposal of byproduct material at sites that process ores primarily for their uranium and thorium source material content 7 or disposal of such byproduct material (commonly known as Title II sites). See 42 U.S.C. 2022. 8 These public health, safety and environmental standards are contained in 40 CFR part 192 and are implemented by the NRC and its Agreement States, as well as the DOE.

6 See 42 U.S.C. 2022.

7 “Source material” is defined as “(1) Uranium or thorium or any combination of uranium or thorium in any chemical or physical form; or (2) Ores that contain, by weight, one-twentieth of one percent (0.05 percent), or more, of uranium or thorium, or any combination of uranium or thorium.” See 42 U.S.C. 2014(z), 10 CFR 20.1003.

8 Although the statute covers both uranium and thorium mill tailings sites, there are no existing thorium mill tailings sites.

Title I of UMTRCA covers inactive uranium milling sites, nearby contaminated “vicinity properties” and depository sites

ieth of one percent (0.05 percent), or more, of uranium or thorium, or any combination of uranium or thorium.” See 42 U.S.C. 2014(z), 10 CFR 20.1003.

8 Although the statute covers both uranium and thorium mill tailings sites, there are no existing thorium mill tailings sites.

Title I of UMTRCA covers inactive uranium milling sites, nearby contaminated “vicinity properties” and depository sites. The EPA was directed to set general standards that are consistent with the requirements of the Solid Waste Disposal Act (later amended as the Resource Conservation and Recovery Act, or RCRA) to the maximum extent practicable. The Title I standards are located in EPA regulations at 40 CFR part 192, subparts A-C.

This proposed rule is based on Title II of the Act, which covers operating uranium processing or disposal facilities licensed by the NRC or NRC Agreement States. The EPA has authority to promulgate standards of general i.e., RCRA). 9 The NRC is required to implement these standards at Title II sites. See 42 U.S.C. 2022(b), (d).

9 With the restriction that the EPA not require any RCRA permit for the processing, possession, transfer or disposal of byproduct material at such facilities.

II. Summary of the Proposed Rule

A. Proposed Standards for Uranium ISR Operations

In today's action, the EPA is proposing to add a new subpart, subpart F, to the EPA's existing regulations for uranium and thorium mill tailings in 40 CFR part 192. The proposed standards would apply only to ISR facilities and are designed to protect public health, safety and the environment from contamination associated with their uranium recovery operations. The proposed standards are summarized in the following sections.

1. Who is subject to the proposed standards?

Subpart F would apply to new and existing ISR facilities, including facilities that have temporarily ceased uranium production ( i.e., ISR facilities in standby)

d to protect public health, safety and the environment from contamination associated with their uranium recovery operations. The proposed standards are summarized in the following sections.

1. Who is subject to the proposed standards?

Subpart F would apply to new and existing ISR facilities, including facilities that have temporarily ceased uranium production ( i.e., ISR facilities in standby). Subpart F would not apply to Title I sites, facilities that use only conventional or heap leach uranium production methods, or Title II ISR wellfields that have already begun or completed restoration within three years of the rule's effective date. The NRC and NRC Agreement States would develop regulations or take other appropriate steps to implement the new subpart F standards, once they are finalized.

2. What are the proposed surface and groundwater standards for ISR facilities?

In the proposed new subpart, the EPA has cross-referenced subpart D to indicate that the existing standards for protecting surface waters and groundwater also apply to ISR facilities. The subpart D standards were initially written to address the handling, storing and disposal of byproduct material produced from the processing of uranium ore.

3. What are the proposed groundwater protection standards for ISR facilities?

Consistent with the original proposal, this proposed rule includes the following three types of groundwater protection standards for ISR facilities: (1) Constituent concentration standards (including provisions for Alternate Concentration Limits (ACLs)); (2) initial stability standards; and (3) long-term stability standards. 10 These standards of general application would apply to all ISR facilities and are intended to prevent the mobilization of uranium and other constituents beyond the production zone during the operational and restoration phases and to ensure, once the wellfield is restored, that the restoration is complete and stable, both immediately after restoration and into the foreseeable future

ty standards. 10 These standards of general application would apply to all ISR facilities and are intended to prevent the mobilization of uranium and other constituents beyond the production zone during the operational and restoration phases and to ensure, once the wellfield is restored, that the restoration is complete and stable, both immediately after restoration and into the foreseeable future.

10 The initial stability standards and the long-term stability standards were originally included in the proposed monitoring programs section of the rule. The initial stability standards (called “short-term stability” in the proposal) was proposed in 40 CFR 192.53(d)(2)(i) and the long-term stability standards were proposed in 40 CFR 192.53(e)(1)(iii). To improve clarity, the initial and long-term stability standards have been moved to 40 CFR 192.52(c)(2) and (c)(3), respectively.

Constituent Concentration Standards. The constituent concentration standards are numerical concentration limits for a set of groundwater constituents that are present in or affected by ISR operations. When corrective action is necessary after an excursion has occurred, the licensee would have to clean-up the groundwater to meet these proposed constituent concentration standards. In addition, during the restoration and stability monitoring phases, these proposed constituent concentration standards would be the levels to which restoration must be achieved and maintained.

In this proposal, the appropriate constituent concentration standards for an ISR facility would be determined by the regulatory agency for each licensee. The constituent concentration standard for each constituent would be the highest level of the following values: (1) The lowest regulatory standard for that constituent found in 40 CFR 141.62, 141.66, 141.80, 143.3, 264.94, and Table 1 to subpart A of 40 CFR part 192; (2) that constituent's preoperational background level in the wellfield; or (3) an ACL for that constituent as approved by the regulatory agency

ent concentration standard for each constituent would be the highest level of the following values: (1) The lowest regulatory standard for that constituent found in 40 CFR 141.62, 141.66, 141.80, 143.3, 264.94, and Table 1 to subpart A of 40 CFR part 192; (2) that constituent's preoperational background level in the wellfield; or (3) an ACL for that constituent as approved by the regulatory agency. When setting the constituent concentration standards for a licensee, the regulatory agency would consider a minimum of 12 constituents. The regulatory agency would not be required to set standards for all 12 constituents, but the regulatory agency would have to set a constituent concentration standard for each of the listed constituents that is present in or could be affected by the ISR operation. The regulatory agency would have to identify the constituents during the preoperational monitoring phase. The regulatory agency would need to consider the following 12 constituents when setting the constituent concentration standards for an ISR operation: Arsenic, barium, cadmium, chromium, lead, mercury, selenium, silver, nitrate (as N), molybdenum, combined radium-226 and radium-228, and uranium (total). The original proposal included gross alpha particle activity (excluding radon and uranium), however, this constituent was not included in this proposal for the reasons explained in section III.3.2. The EPA is specifically requesting comment on the deletion of gross alpha particle activity (excluding radon and uranium) from the list of constituents. The regulatory agency may also set constituent concentration standards for additional constituents beyond these 12 constituents for situations where the regulatory agency considers concentration standards for other constituents necessary due to facility-specific conditions

questing comment on the deletion of gross alpha particle activity (excluding radon and uranium) from the list of constituents. The regulatory agency may also set constituent concentration standards for additional constituents beyond these 12 constituents for situations where the regulatory agency considers concentration standards for other constituents necessary due to facility-specific conditions.

Once these proposed standards are finalized and the regulatory agency implements the subpart F standards, the constituent concentration standards would have to be established in accordance with the provisions in § 192.52 for all new wellfields and expansions to existing wellfields, and for all existing wellfields that are already operating, excluding those that are in and remain in the restoration and stability monitoring phases, as of the date three years after the effective date of this rule. Wellfields that begin and remain in restoration, initial stability monitoring or long-term stability monitoring at a licensed facility prior to the date three years after the effective date of the rule would need to meet the standards established when their license was issued or as otherwise specified by the regulatory agency.

Alternate Concentration Limits. Consistent with the original proposal, this proposal would allow licensees the flexibility to request ACLs when the best practicable active restoration has taken place, as determined by the regulatory agency, and the licensee demonstrates one or more of the constituent concentration standards cannot be met through further groundwater restoration. The best practicable active restoration must be used before the licensee can apply to the regulatory agency for a provisional ACL. Under this proposal, once the regulatory

It must be understood that granting an ACL is an indication that restoration has not returned the affected groundwater to either preoperational background levels or other health-based levels

gh further groundwater restoration. The best practicable active restoration must be used before the licensee can apply to the regulatory agency for a provisional ACL. Under this proposal, once the regulatory

It must be understood that granting an ACL is an indication that restoration has not returned the affected groundwater to either preoperational background levels or other health-based levels. However, there are some overarching principles that must be considered when establishing ACLs. In general, as described in § 192.54, any provisional or final ACL should not pose a substantial present or potential hazard to human health and the environment, as determined by the regulatory agency. Points of exposure are defined in the proposal as locations identified by the regulatory agency that represent possible future areas of exposure where the receptor can come into contact with groundwater ( e.g., areas of recoverable groundwater). The groundwater at the point of exposure should be protective of the receptor. The EPA specifically requests comment on this approach, especially with regard to the overall regulatory model of how ACL application would work, the definition of points of exposure and the use of this term, and the overall environmental, human health and safety protection goals for setting and using ACLs. Commenters, including interagency commenters, raised questions concerning the integration of an aquifer exemption under the SDWA and point of exposure as it was defined in the EPA's original proposal and the differing jurisdictions of the SDWA and UMTRCA

points of exposure and the use of this term, and the overall environmental, human health and safety protection goals for setting and using ACLs. Commenters, including interagency commenters, raised questions concerning the integration of an aquifer exemption under the SDWA and point of exposure as it was defined in the EPA's original proposal and the differing jurisdictions of the SDWA and UMTRCA.

Under this proposal, when considering setting an ACL, the regulatory agency would consider a list of factors, including potential adverse effects on groundwater quality, physical and chemical characteristics of the constituent, including the potential for migration, hydrogeological characteristics of the area, proximity and withdrawal rates of local groundwater users, current and anticipated future uses of the groundwater, existing quality of the groundwater, potential for health risks, potential to damage wildlife, crops, vegetation and physical structures, the persistence and permanence of the potential effects, adverse impacts on hydraulically connected surface water (including several factors) and the presence of any USDW.

The EPA expects that setting a provisional and final ACL will require consideration of the hydrologic and other characteristics of the wellfield and surrounding area, any potential areas of groundwater withdrawal or discharge and be protective of human health into the foreseeable future.

Consistent with UMTRCA, the Tenth Circuit Court of Appeals in the Environmental Defense Fund v. NRC decision, 11 and current practice, the regulatory agency would be responsible for reviewing and approving ACL requests. Although not a proposed provision, the EPA considers it good practice for the regulatory agency to make public the information used for determining whether a provisional ACL is warranted and at what concentration before approving a provisional ACL

nvironmental Defense Fund v. NRC decision, 11 and current practice, the regulatory agency would be responsible for reviewing and approving ACL requests. Although not a proposed provision, the EPA considers it good practice for the regulatory agency to make public the information used for determining whether a provisional ACL is warranted and at what concentration before approving a provisional ACL. Although the NRC has not issued an ACL to date for an ISR wellfield, the NRC current practice would result in making such information publicly available and would support the EPA's effort to increase the effectiveness of the rule.

11 866 F.2d 1263 (10th Cir. 1989).

Stability Standards. In addition to the constituent concentration standards discussed above, licensees would also need to meet initial and long-term stability standards. The initial stability standards would require three consecutive years of quarterly monitoring results showing no statistically significant increasing trends exceeding the ISR facility's constituent concentration standards at the 95 percent confidence level. The long-term stability standards would require an additional three consecutive years of quarterly monitoring results showing no statistically significant increasing trends exceeding the ISR facility's constituent concentration standards at the 95 percent confidence level and also would require the licensee to demonstrate through geochemical modeling and other analysis that the applicable constituent concentration standards will continue to be met in the future. Consistent with the original proposal, the regulatory agency issuing the license would be responsible for determining whether there is reasonable assurance that the applicable constituent concentration standards will continue to be met at the ISR facility in the future.

al modeling and other analysis that the applicable constituent concentration standards will continue to be met in the future. Consistent with the original proposal, the regulatory agency issuing the license would be responsible for determining whether there is reasonable assurance that the applicable constituent concentration standards will continue to be met at the ISR facility in the future.

4. What are the proposed general and preoperational monitoring requirements?

In order to understand the hydrogeology and geochemistry of the production zone and surrounding area and to set the preoperational background for the constituent concentration standards, licensees would develop a preoperational monitoring plan for the wellfield. The preoperational monitoring plan would characterize the hydrogeology and geochemistry of the area, support identification of any potential future excursions from the production zone during the operational and restoration phases, and support the monitoring, modeling and other analysis as determined by the regulatory agency to be necessary to meet the proposed initial and long-term stability standards.

The preoperational monitoring determines the groundwater flow regime and the background groundwater concentrations of the 12 listed constituents and any additional constituents required by the regulatory agency. The data collected during this period would be used to select the indicator parameters and set the upper control limits (UCLs) for these parameters. The indicator parameters would be monitored during the operational and restoration phases and, when the UCL is exceeded, indicate that lixiviant or other constituents are migrating beyond the production zone. The preoperational monitoring would be conducted at wells within the production zone and in areas surrounding the production zone, including aquifers immediately above and below the production zone, and in areas laterally adjacent to the production zone, both up and down gradient

and, when the UCL is exceeded, indicate that lixiviant or other constituents are migrating beyond the production zone. The preoperational monitoring would be conducted at wells within the production zone and in areas surrounding the production zone, including aquifers immediately above and below the production zone, and in areas laterally adjacent to the production zone, both up and down gradient. A sufficient number of wells would have to be installed and monitored so that the sampling data collected could be used to statistically determine appropriate background levels and support statistical tests, modeling and other analysis determined by the regulatory agency to be necessary during the operational, restoration, initial stability and long-term stability phases. The licensee would collect a sufficient number of sample sets per well over a time period sufficient to indicate a statistically valid background concentration that is not affected by well installation or temporal variations. In areas where temporal ( e.g., seasonal) variation could occur ( e.g., ore zones in unconfined aquifers), the preoperational monitoring would be conducted for at least one year in a sufficient number of wells to adequately represent the hydrologic system.

In addition to monitoring the concentrations of the constituents required by the regulatory agency, the licensee would collect any other data necessary to establish background conditions to support future modeling and other analysis in preparation to meet the proposed long-term stability standards in § 192.52(c)(3).

5. What are the proposed monitoring requirements for the operational and restoration phases?

t the proposed long-term stability standards in § 192.52(c)(3).

5. What are the proposed monitoring requirements for the operational and restoration phases?

To ensure that no lixiviant, uranium or other constituents are migrating outside of the production zone, the licensee would monitor groundwater for specified indicator parameters at a set of monitoring wells surrounding the production zone. These excursion monitoring wells would be located around the perimeter of the production zone and in any aquifers immediately above or below the production zone that may be impacted by ISR activities. That is, the excursion monitoring wells need to surround the production zone in three dimensions. The excursion monitoring wells would be of sufficient number, density, and placement to detect the possibility of an excursion from the production zone. The regulatory agency would be responsible for reviewing and, when appropriate, approving well placement and installation, indicator parameters, the UCLs for the indicator parameters, as well as background levels for constituents for which constituent concentration standards are set.

Typical indicator parameters used to identify possible excursions include chloride, conductivity and total alkalinity. Other parameters may be appropriate as well. In the proposed rule, an excursion has occurred when either (1) two indicator parameters exceed their respective UCLs in any excursion monitoring well; or (2) as determined by the regulatory agency, one indicator parameter significantly exceeds its UCL in any excursion monitoring well. The EPA specifically requests comment on this proposed definition of an excursion and suggestions for other approaches for determining when an excursion has occurred. If an excursion occurs, the licensee would need to initiate corrective action in accordance with its facility-specific corrective action program and would be required to test for all constituents for which a constituent concentration standard was established

ests comment on this proposed definition of an excursion and suggestions for other approaches for determining when an excursion has occurred. If an excursion occurs, the licensee would need to initiate corrective action in accordance with its facility-specific corrective action program and would be required to test for all constituents for which a constituent concentration standard was established. At a minimum, the constituents from Table 1 that are typically present and that warrant monitoring during an excursion are uranium, radium, arsenic and selenium. The regulatory agency would be allowed to identify additional constituents that are present in the groundwater and need to be monitored on a facility-specific basis.

In some cases, a licensee may have temporarily stopped recovering uranium and the facility may be in a phase commonly called “standby” by the industry. In such instances, the EPA considers the facility to be in the operational phase and the licensee would be required under the proposed rule to continue monitoring and taking actions, such as maintaining an inward hydraulic gradient, to prevent excursions.

6. What monitoring is proposed for the initial stability standards?

Once the licensee believes restoration is near completion and believes they can, over time, demonstrate that the proposed initial stability standards in § 192.52(c)(2) can be met, the EPA expects that the licensee would begin monitoring the groundwater constituent concentrations throughout the wellfield to determine when the initial stability standards have been met. To meet the proposed initial stability standards, the licensee would need to demonstrate stability by providing three consecutive years of quarterly monitoring results showing no statistically significant increasing trend exceeding each established constituent concentration standard. For all monitored constituents, this trend would need to be demonstrated at the 95 percent confidence level

en met. To meet the proposed initial stability standards, the licensee would need to demonstrate stability by providing three consecutive years of quarterly monitoring results showing no statistically significant increasing trend exceeding each established constituent concentration standard. For all monitored constituents, this trend would need to be demonstrated at the 95 percent confidence level. The licensee would be required to develop and implement a compliance monitoring program approved by the regulatory agency that identifies compliance points encompassing the entire affected area of the wellfield.

The purpose of the proposed stability monitoring is to determine whether constituent levels in the entire affected area of the wellfield, including the production zone, have returned to levels below the established constituent concentration standards and stable conditions are established. Hence, compliance wells must include wells previously used as excursion monitoring wells and those previously used as production related wells. The location of the compliance wells used to determine compliance with the initial stability standards would need to be approved by the regulatory agency and would need to be located in areas likely to be affected by ISR operations. Therefore, compliance well would be located within the production zone, adjacent to the production zone and in aquifers located immediately above and below the production zone, as approved by the regulatory agency. The number and location of compliance wells will vary depending on the size and characteristics of the wellfield, but should encompass the entire affected area of the wellfield.

ut should encompass the entire affected area of the wellfield.

To meet the proposed initial stability standards of § 192.52(c)(2), measurements would need to be taken quarterly at each well. If one or more constituents exceed a constituent concentration standard during the initial stability monitoring, then the licensee would follow the corrective action program approved by the regulatory agency. When monitoring to assess whether the initial stability standards have been met, constituent concentrations may fluctuate above the respective standard. The corrective action program should address the possibility of and the regulatory agency should consider potential responses to an exceedance of the constituent concentration standards while the licensee is establishing a statistically adequate trend. The regulatory agency may allow continued monitoring, if appropriate, or require the licensee to undertake a remedy. Regardless of the action taken, the licensee would be required by the proposed standards to achieve three consecutive years of stable measurements. Furthermore, as in all phases, if lixiviant or other constituents escape the production zone, the licensee would be required to take the necessary actions to return the aquifer to below the constituent concentration standards.

When the licensee demonstrates three consecutive years of quarterly monitoring results showing no statistically significant increasing trends exceeding the established constituent concentration standards at the 95 percent confidence level, then the facility has met the proposed initial stability standards and the licensee may, upon the determination of the regulating agency that the initial stability standards have been satisfied, begin long-term stability monitoring.

ng results showing no statistically significant increasing trends exceeding the established constituent concentration standards at the 95 percent confidence level, then the facility has met the proposed initial stability standards and the licensee may, upon the determination of the regulating agency that the initial stability standards have been satisfied, begin long-term stability monitoring.

7. What are the proposed requirements for the long-term stability standards?

During the proposed long-term stability monitoring, the licensee continues quarterly monitoring to demonstrate compliance with the constituent concentration standards using the compliance wells established for monitoring during the initial stability phase. To meet the proposed long-term stability standards in § 192.52(c)(3), the licensee would need to first demonstrate quarterly monitoring results for a minimum of three consecutive years showing no statistically significant increasing trends exceeding the established constituent concentration standards (including any approved ACLs) at the 95 percent confidence level.

To approve cessation of long-term stability monitoring, the regulatory agency would be responsible for determining whether there is reasonable

(i) Conceptual hydrogeochemical modeling for the mine unit/production zone;

(ii) Ground water and solid (core) data used for geochemical model(s), including field parameters;

(iii) Incorporation of ground water data in an initial geochemical model ( i.e., saturation indices calculations and assessment);

(iv) Demonstration that stability (mainly reduction-oxidation or redox) conditions can be maintained in the production zone;

ling for the mine unit/production zone;

(ii) Ground water and solid (core) data used for geochemical model(s), including field parameters;

(iii) Incorporation of ground water data in an initial geochemical model ( i.e., saturation indices calculations and assessment);

(iv) Demonstration that stability (mainly reduction-oxidation or redox) conditions can be maintained in the production zone;

(v) Demonstration that ground water migrating into the production zone will not significantly change the geochemical stability within the production zone;

(vi) Demonstration of alternative geochemical conditions that demonstrate stability (uranium and other elements); and

(vii) Inter-relationships and contradictory claims (unintended consequences) for these various elements need to be identified and assessed in the context of the conceptual hydrogeochemical model.

The EPA requests comment on whether these seven elements should be required at all sites and thus included in the standards in 40 CFR part 192, subpart F.

The regulatory agency has the responsibility to establish the timeframe for long-term stability monitoring, based on facility-specific conditions at the wellfield and the results of long-term stability monitoring, modeling and analysis. If one or more constituents exceed their concentration standard (or approved ACL) or show a statistically significant increasing trend during the long-term stability phase, the regulatory agency may require the licensee to take corrective action as specified in the facility's corrective action program.

8. What are the proposed corrective action requirements?

orrective action requirements?

Each licensee would be required to develop a corrective action program that addresses the actions it will take when an excursion is detected during the operational and restoration phases, or when monitoring during the stability phases shows a concentration higher than the established constituent concentration standard or a statistically significant increasing trend. Corrective action, as identified in the corrective action program and approved by the regulatory agency, would be initiated as soon as practicable and would begin within 60 days of the date the excursion or exceedance of a constituent concentration standard is detected. The corrective action program would consider a range of possibilities for action from the operational phase through the long-term stability monitoring phase. Corrective action may include removing or treating in place any constituents that exceed the constituent concentration standards (or approved ACL). If the concentration of one or more constituents exceeds the constituent concentration standard (or approved ACL) during long-term stability monitoring, the licensee would be required to take corrective action to restore the groundwater to comply with the proposed constituent concentration standards; once restoration is complete, the licensee would begin again with initial stability monitoring.

B. Proposed Amendments to 40 CFR Part 192, Subparts C and D

As part of this rulemaking, the EPA is also proposing several minor amendments to the provisions in 40 CFR part 192, subparts C and D. These amendments are described in this section and are not related to the new standards for ISR facilities added in 40 CFR part 192, subpart F.

1. What are the proposed revisions to § 192.32(a)(2)(v)?

e amendments are described in this section and are not related to the new standards for ISR facilities added in 40 CFR part 192, subpart F.

1. What are the proposed revisions to § 192.32(a)(2)(v)?

This proposed rule deletes the requirement in § 192.32(a)(2)(v) for the NRC to obtain concurrence from the EPA before the NRC may approve alternative requirements or proposals under AEA section 84(c). 12 As the EPA stated in the proposal, this portion of § 192.32(a)(2)(v) was effectively struck down by the Tenth Circuit Court of Appeals in Environmental Defense Fund vs. U.S. Nuclear Regulatory Commission , 866 F.2d 1263 (10th Cir. 1989). In its decision, the Court ruled that the NRC has authority under AEA section 84(c) to independently make these facility-specific determinations, and that the NRC has no duty to obtain the EPA's concurrence.

12 See 42 U.S.C. 2114(c).

2. What are the proposed miscellaneous updates and corrections?

The EPA is also proposing several minor amendments to subparts C and D to correct cross-references, typographical and punctuation errors. These amendments include the following:

Section Description of proposed technical correction Rationale for correction 40 CFR part 192, subpart C 192.20(b)(3) Delete reference to “Pub. L. 92-314 (10 CFR part 712)” The Grand Junction Remedial Action Criteria to which this reference applied no longer exist in the CFR. 192.20(b)(3) Delete language referencing sealants and filtration Methods were found to be ineffective and are no longer recommended as remedial options for radon mitigation. 40 CFR part 192, subpart D § 192.31(a) Replace “Uranium Mill Tailings Rediation Control Act” with “Uranium Mill Tailings Radiation Control Act” Corrects a typographical error. § 192.31(f) Replace “pile containing uranium by product materials” with “pile containing uranium byproduct materials” Corrects a typographical error. § 192.32(a)(2)(v) Replace “laser fusion, of soils, etc.” with “laser fusion of soils, etc.” Corrects a punctuation error. III

nium Mill Tailings Rediation Control Act” with “Uranium Mill Tailings Radiation Control Act” Corrects a typographical error. § 192.31(f) Replace “pile containing uranium by product materials” with “pile containing uranium byproduct materials” Corrects a typographical error. § 192.32(a)(2)(v) Replace “laser fusion, of soils, etc.” with “laser fusion of soils, etc.” Corrects a punctuation error. III. Summary of Changes Made to the Original Proposal and Rationale for Those Changes

As previously indicated, the standards proposed in today's action differ from those standards proposed on January 26, 2015 (80 FR 4156). This section of the preamble describes the most significant changes made to the original proposal and the rationale for those changes. Many of the changes were made in response to public comments and additional information provided by stakeholders. In response to the original proposal, the EPA received over 5,380 public comment letters on the proposed amendments, of which 5,192 were duplicate letters. The comments covered more than 80 different topics and were submitted by a wide range of stakeholders, including private citizens, public interest groups, industry, Indian tribes, state agencies and other federal agencies. For the original proposal, the EPA also held public hearings in Corpus Christi, TX (April 14, 2015); Washington, DC (March 10, 2015); Casper, WY (May 13 and 14, 2015); and Chadron, NE (May 12, 2015), where 114 stakeholders provided comments.

In addition to describing the changes made to the original proposal, this section also discusses and responds to the significant comments that resulted in many of those changes. The significant comments received that did not result in changes to the original proposal are discussed in section IV of the preamble.

2015); and Chadron, NE (May 12, 2015), where 114 stakeholders provided comments.

A. Incorporation of the Initial and Long-Term Stability Standards in Proposed 40 CFR 192.52

For clarity, the EPA has restructured the proposed rule to move the initial and long-term stability standards that were originally included with the monitoring requirements in § 192.53 to the standards in § 192.52. The initial stability standards (called “stability” or “short-term stability” in the original proposal) were proposed in § 192.53(d)(2)(i), and the long-term stability standards were proposed in § 192.53(e)(1)(iii). In this proposal, the initial and long-term stability standards have been moved to § 192.52(c)(2) and (c)(3), respectively.

B. Groundwater Protection Standards

1. Clarifications to Terminology

The original January 2015 proposal listed 13 constituents for which a facility-specific concentration limit must be set for each constituent that is present in the groundwater. In the original proposal, the EPA referred to these facility-specific concentration limits as “groundwater protection standards” and “restoration goals” (see § 192.52(c) of the original proposed rule). Since the use of these two terms may lead to confusion, the EPA is no longer using the term “restoration goals” but is instead using the term “constituent concentration standards” throughout the proposed rule to refer to these facility-specific concentration limits.

als” but is instead using the term “constituent concentration standards” throughout the proposed rule to refer to these facility-specific concentration limits.

In the original proposed rule, the EPA also used the phrase “identified in the groundwater” when referring to constituents for which constituent concentration standards should be established (see § 192.52(c) of the original proposed rule). The EPA intended concentration standards to be set for any constituent that is present in groundwater before or after ISR activities have begun. Some constituents may not be initially present in the groundwater but may become soluble only after lixiviant is injected and groundwater chemistry has been altered. However, the phrase “identified in the groundwater” could be misinterpreted to mean only those that are present during preoperational monitoring. For clarification, the EPA has revised the original proposal to specify that constituent concentration standards must be established for all constituents that are “identified as present or affected by operations in the groundwater.”

2. Gross Alpha Particle Activity

In the original proposal, the list of constituents in Table 1 of subpart F included gross alpha particle activity. 13 Several commenters opposed listing gross alpha particle activity, stating that it provided no useful information that could not be otherwise obtained from the required measurement of radionuclides, such as radium 226. In addition, commenters noted the wide uncertainty range for the radiochemistry analytical methodology currently used to measure gross alpha activity.

13 The SDWA MCL of 15 pCi/L for gross alpha particle activity excludes alpha particle activity contributions from radon and uranium.

The EPA tends to agree with commenters who suggested that gross alpha measurements are likely to be of limited value when other radionuclides of concern are also being sampled

e radiochemistry analytical methodology currently used to measure gross alpha activity.

13 The SDWA MCL of 15 pCi/L for gross alpha particle activity excludes alpha particle activity contributions from radon and uranium.

The EPA tends to agree with commenters who suggested that gross alpha measurements are likely to be of limited value when other radionuclides of concern are also being sampled. The Agency also recognizes that the uncertainty associated with gross alpha measurements may be greater than those for other constituents, which may make the application of statistical tests especially complicated. However, gross alpha is specified as a constituent to be sampled in other subparts of 40 CFR part 192, and it does have a maximum contaminant level (MCL), which cannot be overlooked. Further, there may be instances where gross alpha measurements provide information regarding the presence of decay products such as lead and polonium. The EPA is specifically requesting comment on the deletion of gross alpha particle activity as one of the original proposal's 13 constituents, whether it provides useful information, and how measurement uncertainty might be addressed.

C. Preoperational Monitoring Requirements

In the original proposal, the EPA included provisions for preoperational monitoring that were designed to characterize the groundwater flow regime, geology and geochemistry. The EPA originally proposed that preoperational monitoring would measure the background concentrations of radiological and non-radiological constituents, including all the constituents listed in Table 1 of subpart F, and any additional constituents or parameters specified by the regulatory agency or needed for calculations or groundwater modeling. The original proposal required preoperational monitoring be continued for a minimum of one year in order to account for any temporal changes occurring in the aquifer

cal and non-radiological constituents, including all the constituents listed in Table 1 of subpart F, and any additional constituents or parameters specified by the regulatory agency or needed for calculations or groundwater modeling. The original proposal required preoperational monitoring be continued for a minimum of one year in order to account for any temporal changes occurring in the aquifer. The EPA also proposed some requirements for the location of the wells, requiring monitoring wells to be located in overlying aquifers, underlying aquifers, inside the exempted aquifer and outside the exempted aquifer, including areas that

1. Duration of Preoperational Monitoring

The EPA received a number of comments on the duration of the proposed preoperational monitoring requirements. Some commenters supported the one-year timeframe, while others recommended the time period be extended to up to two years. Many commenters cited the NRC Criterion 7 from 10 CFR part 40, Appendix A, which requires uranium mills to complete one or more years of preoperational monitoring before a company can submit a license application. Two commenters noted that some aquifers do not experience seasonal variations in groundwater constituents. For example, commenters asserted there may be no seasonally influenced fluctuation in the concentrations of groundwater constituents in deeper target ore production aquifers.

Based on all of these comments, the EPA has refined the approach to preoperational monitoring. Instead, the Agency is proposing that preoperational monitoring of wells screened in areas where temporal variations are not expected to occur, such as in deep ore zones in confined aquifers, would be allowed to monitor for periods of less than one year. However, the licensee would collect several sets of samples over a time period sufficient to demonstrate seasonal variability does not occur

ing. Instead, the Agency is proposing that preoperational monitoring of wells screened in areas where temporal variations are not expected to occur, such as in deep ore zones in confined aquifers, would be allowed to monitor for periods of less than one year. However, the licensee would collect several sets of samples over a time period sufficient to demonstrate seasonal variability does not occur. For example, in some cases, four sets of samples collected over several months would be adequate to determine the background for systems that do not exhibit seasonal changes. In this proposal, sample sets collected over a period of at least one year would still be necessary for facilities that operate in areas where constituent concentrations are expected to exhibit seasonal fluctuations. The regulatory agency would determine whether the licensee's preoperational monitoring is of sufficient duration and that sampling occurs at appropriate intervals to establish the background concentrations for all 12 constituents, as well other constituents identified by the regulatory agency and all indicator parameters. To provide flexibility where appropriate, the EPA did not propose an across-the-board two-year monitoring requirement, although the regulatory agency would be allowed to do what is necessary to reflect seasonal or other variation in background constituent concentrations or flow.

2. Changes to the Well Completion Requirements

The Agency received several comments on the original proposed requirements for well completions. A general concern expressed by the commenters is that true baseline conditions of the groundwater constituents cannot be established if the well drilling and development methods introduce oxygen into the groundwater. The commenters explained that since oxygen may increase the solubility of uranium, elevated baseline concentrations will lead to artificially high restoration goals

well completions. A general concern expressed by the commenters is that true baseline conditions of the groundwater constituents cannot be established if the well drilling and development methods introduce oxygen into the groundwater. The commenters explained that since oxygen may increase the solubility of uranium, elevated baseline concentrations will lead to artificially high restoration goals. Commenters suggested several methods to alleviate this concern, including air-rotary drilling with recirculated nitrogen gas instead of air and a foam surfactant that contains organic constituents to eliminate oxygen.

After considering these comments, the EPA believes sufficient monitoring should be completed to ensure all perturbations associated with well construction are resolved prior to establishing the background concentrations. To achieve this goal, under this proposed action, the licensee would collect several sets of samples over a time period sufficient to demonstrate baseline conditions that are unaffected by monitoring well construction. In the proposal, the EPA requires the sampling frequency to be sufficient to ensure statistically valid background levels that are not influenced by well construction. The samples used for this purpose may be the same as those used for the temporal variability analyses, if technically feasible. The regulatory agency would determine whether the licensee's well construction follows appropriate protocols and that sampling occurs at appropriate intervals to establish accurate background concentrations.

D. Exempted Aquifers

The EPA originally proposed that preoperational monitoring wells, excursion monitoring wells used during the operational and restoration phases, and compliance wells used during the initial and long-term stability monitoring phases (referred to as “point(s) of compliance”) be located inside and outside of “exempted aquifers” (see the proposed definition for “point(s) of compliance” at 80 FR 4184). In the original proposal, the EPA also defined the term “point(s) of exposure” as the “intersection of a vertical plane with the boundary of the exempted aquifer” and the term “adjacent aquifer” as an aquifer or portion of an aquifer that “shares a border or end point with the exempted aquifer or the exempted portion of an aquifer” (see 80 FR 4183-4184). As the EPA explained in the original proposal, the term “exempted aquifer” refers to aquifers that are exempted from the protections afforded by the SDWA (see 80 FR 4160).

Under the SDWA, the EPA sets health-based standards for drinking water to protect against naturally occurring and anthropogenic contaminants that may be found in surface and groundwater sources of drinking water. Additionally, under SDWA authority, the EPA promulgated Underground Injection Control (UIC) Program regulations to ensure protection of USDWs, 14 which may be consumed now or in the future, where injection activities are occurring. The UIC regulations at 40 CFR 144.12 prohibit any injection activity that allows the movement of fluid containing any contaminant into USDWs if the presence of that contaminant may cause a violation of any primary drinking water standard or otherwise adversely affect the health of persons

protection of USDWs, 14 which may be consumed now or in the future, where injection activities are occurring. The UIC regulations at 40 CFR 144.12 prohibit any injection activity that allows the movement of fluid containing any contaminant into USDWs if the presence of that contaminant may cause a violation of any primary drinking water standard or otherwise adversely affect the health of persons. Under UIC Program regulations, an aquifer or a portion of an aquifer may be exempted from the protections afforded USDWs, under the SDWA, if (a) it does not currently serve as a source of drinking water; and (b) it cannot now and will not in the future serve as a source of drinking water because one of four specified conditions is met, or (c) the total dissolved solids content of the groundwater is more than 3,000 mg/L and less than 10,000 mg/L and it is not reasonably expected to supply a public water system (see § 146.4). The four conditions referenced above for the aquifer exemption criteria at 40 CFR 146.4(b) are:

14 USDWs are defined, by regulation at 40 CFR 144.3, as: “An aquifer or its portion: (a)(1) Which supplies any public water system; or (2) Which contains a sufficient quantity of ground water to supply a public water system; and (i) Currently supplies drinking water for human consumption; or (ii) Contains fewer than 10,000 mg/l total dissolved solids; and (b) Which is not an exempted aquifer.”

(1) It is mineral, hydrocarbon or geothermal energy producing, or can be demonstrated by a permit applicant as part of a permit application for a Class II or III operation to contain minerals or hydrocarbons that considering their quantity and location are expected to be commercially producible.

(2) It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical;

(3) It is so contaminated that it would be economically or technologically impractical to render that water fit for human consumption; or

inerals or hydrocarbons that considering their quantity and location are expected to be commercially producible.

(2) It is situated at a depth or location which makes recovery of water for drinking water purposes economically or technologically impractical;

(3) It is so contaminated that it would be economically or technologically impractical to render that water fit for human consumption; or

(4) It is located over a Class III well mining area subject to subsidence or catastrophic collapse.

1. Removal of References to “Exempted Aquifer”

In this proposal, the EPA has removed references to “exempted aquifers”, deleted the definitions of “adjacent aquifer” and “exempted aquifer” from § 192.51, and removed the phrase “exempted aquifer” from the definition of “background” in § 192.51 and from the requirements specifying where monitoring wells must be located. This change to the original proposal was made to help clarify that these standards under UMTRCA complement, and do not overlap with, the requirements of the SDWA. As discussed in section I.B., the scope and level of protection of the SDWA differs from the UMTRCA as groundwater at uranium ISR sites could have beneficial uses even if the aquifer has been exempted from protection under the SDWA. Since UMTRCA provides authority that can be used to protect aquifers during and after uranium recovery operations, regardless of whether the aquifer meets the definition of an USDW as defined in EPA's UIC regulations or is exempted from the protections of the SDWA, the scope of UMTRCA's protection should be reflected in the regulatory text of these standards rather than relying on the SDWA UIC exemption regulations. Thus, the regulatory text proposed in this action does not depend on or use the term exempt aquifer

rdless of whether the aquifer meets the definition of an USDW as defined in EPA's UIC regulations or is exempted from the protections of the SDWA, the scope of UMTRCA's protection should be reflected in the regulatory text of these standards rather than relying on the SDWA UIC exemption regulations. Thus, the regulatory text proposed in this action does not depend on or use the term exempt aquifer. Also, although a remote possibility, because ISR facilities may be located in aquifers that are not designated as “exempted aquifers” under the SDWA, under the original proposal there would have been a lack of clarity on how a facility located in a non-exempt aquifer would comply with a rule using “exempt aquifer” boundaries in the regulatory text.

Aquifer Exemptions at ISR facilities. The EPA recognizes that almost all ISR facilities may be considering Class III injection into a formation that meets the UIC regulatory definition of a USDW and is afforded SDWA protection. In such scenarios, in addition to applying for a Class III permit, a Class III owner or operator must (1) apply to the appropriate UIC Program for an aquifer exemption pursuant to requirements at 40 CFR 144.7 and 146.4 (or applicable state requirements), or (2) ensure that the boundaries of an existing exemption are appropriately delineated for the proposed injection activity. While aquifer exemptions facilitate commercial production of minerals and hydrocarbons under specific conditions, the UIC Program requirements are intended to ensure protection of non-exempted portions of a formation which meet the definition of a USDW even where ACLs may be established at an ISR site located within an exempted portion of that aquifer.

n where ACLs may be established at an ISR site located within an exempted portion of that aquifer.

As stated above, this proposed rule is established under the UMTRCA and not under the SDWA; however, both the UMTRCA and the SDWA requirements may apply to ISR facilities. As discussed above and in section I.A., the requirements of these statutes are complementary and not overlapping or duplicative. The SDWA requirements provide for permits to inject lixiviant and recover uranium and possible exemption of the production zone from SDWA requirements. The proposed UMTRCA requirements protect adjacent aquifers that are not exempt from SDWA by requiring monitoring and corrective action, if necessary, during the operational and restoration phases in and around the ore zone after production ceases. The SDWA does not prevent recovery and use of the water within exempted aquifers (including where ISR operations were previously conducted) for private drinking water supply, public water supply, or other uses.

2. Changes to the Definition of “Point(s) of Exposure”

Points of exposure are defined in the proposal as locations identified by the regulatory agency that represent possible future areas of exposure where the receptor can come into contact with groundwater ( e.g., areas of recoverable groundwater). The groundwater at the point of exposure should be protective of the receptor. As noted earlier in this preamble, commenters, including interagency commenters, raised questions concerning the integration of an aquifer exemption under the SDWA and point of exposure as it was defined in the EPA's original proposal and the differing jurisdictions of the SDWA and UMTRCA. The EPA specifically requests comment on this approach, especially with regard to the overall regulatory model of how ACL application would work, the definition of points of exposure and the use of this term, and the overall environmental, human health and safety protection goals for setting and using ACLs.

in the EPA's original proposal and the differing jurisdictions of the SDWA and UMTRCA. The EPA specifically requests comment on this approach, especially with regard to the overall regulatory model of how ACL application would work, the definition of points of exposure and the use of this term, and the overall environmental, human health and safety protection goals for setting and using ACLs.

E. Excursions

In the original proposal, the EPA defined an excursion as “the movement of fluids containing uranium byproduct materials from an ISR production zone into surrounding groundwater” and specified that an excursion has occurred when “. . . any two indicator parameters . . . exceed their respective upper control limits” (see 80 FR 4184).

1. Changes to the Definition

Although the EPA generally considers that an excursion has occurred when any two parameters are above the UCL, in this proposal, the EPA provides flexibility for the regulatory agency to determine that an excursion has occurred when any single indicator parameter significantly exceeds its UCL. The EPA made this change to the proposed definition because in some situations a single parameter may be sufficiently high to indicate a possible excursion. The EPA emphasizes that this would be a judgement of the regulatory agency, and the Agency's understanding is that it is consistent with current NRC practice.

In this proposal, the EPA also revised the definition of excursion to indicate that an excursion includes the movement of fluids containing lixiviant, as well as any fluids containing uranium byproduct material, because these fluids may migrate outside of the ISR production zone. The EPA replaced the reference to “the ISR production zone” with “ISR wellfield” to indicate a broader scope of consideration is necessary in order to ensure that background is appropriately addressed and to ensure that areas within and surrounding the production zone are stable.

fluids containing uranium byproduct material, because these fluids may migrate outside of the ISR production zone. The EPA replaced the reference to “the ISR production zone” with “ISR wellfield” to indicate a broader scope of consideration is necessary in order to ensure that background is appropriately addressed and to ensure that areas within and surrounding the production zone are stable.

2. Changes to the Constituents Required To Be Monitored During the Different Phases of Operation

The EPA originally proposed that licensees would be required to monitor for all constituents listed in Table 1 of 40 CFR part 192, subpart F, during the different phases of operation at an ISR facility. In this proposal, the EPA changed this requirement such that facilities would be required only to monitor for those constituents that are expected to be present ( e.g., uranium, radium, selenium and arsenic) based on the preoperational monitoring and any other constituents identified by the regulatory agency. The EPA made this change to the monitoring parameters to ensure monitoring requirements are established based on data indicating the expected contaminants. This change reduces the monitoring burden for ISR facilities compared to the original proposal. This proposed change also provides the regulatory agency flexibility to specify any other constituents not listed in Table 1 of 40

F. Initial and Long-Term Stability

After restoration ends, ISR facilities must demonstrate compliance with the proposed constituent concentration standards, and also demonstrate those levels will persist and remain stable in the future. In the original proposal, to demonstrate stability, the EPA proposed three consecutive years of stability monitoring with stability demonstrated at the 95 percent confidence level followed by long-term monitoring for an additional period of 30-years. The originally proposed long-term stability monitoring would have allowed facilities to cease monitoring once they had completed monitoring for 30 years

the original proposal, to demonstrate stability, the EPA proposed three consecutive years of stability monitoring with stability demonstrated at the 95 percent confidence level followed by long-term monitoring for an additional period of 30-years. The originally proposed long-term stability monitoring would have allowed facilities to cease monitoring once they had completed monitoring for 30 years. However, the original proposal also allowed a licensee to shorten the 30-year long-term stability monitoring period by demonstrating geochemical stability through monitoring and geochemical modeling.

1. Statutory Authority and 30-Year Long-Term Monitoring

The EPA derived the 30-year long-term stability monitoring period in the original proposal based on consideration of the Agency's statutory mandate to be consistent with the requirements applied to managing hazardous waste under RCRA.

Numerous commenters thought the proposed 30 years of long-term monitoring was not justified, and was excessive and unnecessary. The general positions of these commenters were that these very specific monitoring time frames were outside the EPA's statutory authority under the UMTRCA to promulgate “standards of general application” and that there is no evidence that ISR facilities have impacted offsite underground sources of drinking water. Commenters also thought the requirement would have a significant economic impact, including impacts on leasing and surety costs that would place a number of ISR companies out of business. Other commenters noted that ISR facilities are not equivalent to RCRA hazardous waste facilities and should not be similarly regulated. Some commenters were concerned the long-term monitoring requirements would increase radiologic dose to employees maintaining the processing plant and well fields, which would be inconsistent with the NRC's ALARA (As Low As Reasonably Achievable) regulations found in 10 CFR part 20

noted that ISR facilities are not equivalent to RCRA hazardous waste facilities and should not be similarly regulated. Some commenters were concerned the long-term monitoring requirements would increase radiologic dose to employees maintaining the processing plant and well fields, which would be inconsistent with the NRC's ALARA (As Low As Reasonably Achievable) regulations found in 10 CFR part 20. However, other commenters strongly supported the 30-year monitoring time frame or recommended a longer time frame. These commenters felt that 30 or more years of monitoring would provide sufficient time to detect instability and potential migration of constituents.

2. Proposed Requirements for Initial and Long-Term Stability

Under UMTRCA, the EPA has authority to promulgate “standards of general application” for the protection of public health, safety and the environment from the radiological and non-radiological hazards associated with the processing and the possession, transfer and disposal of byproduct material at uranium ISR facilities. 42 U.S.C. 2022(b). The Tenth Circuit Court of Appeals has clearly recognized that this authority encompasses the ability for the EPA to include monitoring as part of its “standards of general application.” American Mining Congress et al. v. Thomas, 772 F.2d 640, 644, 647-649 (10th Cir. 1985) (“The regulations necessitate monitoring programs.” ). In the proposal, the EPA has retained the initial and long-term stability monitoring requirements but has removed the default requirement for 30 years of long-term monitoring. The initial stability monitoring period remains the same as in the original proposed rule ( i.e., at least three years)

omas, 772 F.2d 640, 644, 647-649 (10th Cir. 1985) (“The regulations necessitate monitoring programs.” ). In the proposal, the EPA has retained the initial and long-term stability monitoring requirements but has removed the default requirement for 30 years of long-term monitoring. The initial stability monitoring period remains the same as in the original proposed rule ( i.e., at least three years). Under this proposal, the duration of the long-term stability monitoring must be at least three years, and the regulatory agency would determine the appropriate length of any additional long-term stability monitoring based on criteria that will enable the licensee to demonstrate, as appropriate, that there is reasonable assurance that the applicable constituent concentration standards will continue to be met in the future. Similar performance criteria were part of the standards in the original proposed rule, where the EPA had proposed that licensees would be required to demonstrate three consecutive years of initial stability monitoring and then maintain long-term stability monitoring for an additional period of 30 years. The original proposal included an option that allowed a licensee to shorten the 30-year timeframe by demonstrating long-term geochemical stability through modeling. Under this proposal, modeling would no longer be optional. Consistent with the original proposal, the EPA is proposing that the regulatory agency would be responsible for reviewing the licensee's data and analysis, and making the determination of when the licensee could discontinue long-term stability monitoring and initiate decommissioning.

oning.

While many commenters supported the 30-year monitoring requirement, and some even preferred a longer period, the proposal maintains the same performance-based standards for the long-term stability phase as the original proposal and hence ensures the same level of protection the EPA anticipated in the original proposal. The Agency emphasizes the role of modeling in achieving that objective. As explained in the original proposal, the Agency expected that licensees would make extensive efforts to develop robust models that would significantly shorten the long-term monitoring period. In fact, as presented in the proposal, it would have been possible for a licensee to submit modeling such that no (or minimal) long-term monitoring would be necessary. However, should licensees be unable to provide such modeling, or choose not to, the additional monitoring would have provided the level of confidence necessary for the regulatory agency to determine that long-term stability had been demonstrated. This revised proposal relies on modeling and analysis to as an essential element in concluding that groundwater will continue to meet the applicable constituent concentration standards into the foreseeable future, leading to the Agency's judgment that the revised approach is comparable in protectiveness to the original proposal.

As noted above, other commenters stated that 30 years of monitoring would not add value and would put many companies out of business. ISR facilities that disturb groundwater and mobilize constituents of concern are responsible for restoring disturbed groundwater to background or health-based conditions regardless of the time required to achieve this goal. However, the EPA also agrees with commenters who noted the time period necessary to establish stability at an ISR facility is variable due to differences in geology, hydrology and geochemistry

hat disturb groundwater and mobilize constituents of concern are responsible for restoring disturbed groundwater to background or health-based conditions regardless of the time required to achieve this goal. However, the EPA also agrees with commenters who noted the time period necessary to establish stability at an ISR facility is variable due to differences in geology, hydrology and geochemistry. As reflected by one of the commenters, after 10 years of monitoring at the Kingsville Dome ISR facility, it appears that reducing conditions have not been re-established in the production zone. Restoration at Christensen Ranch has not been approved by the NRC because the NRC found that restoration was not complete and water quality was not stable after completion of uranium recovery in 2005. 15 Uranium concentrations also

15 NRC (2012), “Technical Evaluation Report: Christensen Ranch Mine Units 2 through 6 http://www.nrc.gov/docs/ML1217/ML12174A048.pdf .

This proposal defines the initial stability standards as “three consecutive years of quarterly monitoring results with no statistically significant increasing trends exceeding the constituent concentration standards at the 95 percent confidence level.” These performance-based standards would apply after the licensee completes restoration and, once met, would demonstrate that restoration was initially successful. The EPA requests comment on this approach and the wording of the regulatory text. Alternative language the EPA considered for this proposal for both initial and long term stability, included requiring the licensee to show “ . . . three consecutive years of quarterly monitoring results demonstrating a statistically significant non-increasing trend at the 95 percent confidence level remaining below each constituent concentration standard.” This alternative approach, which would require the licensee to demonstrate that the trend line is either horizontal or decreasing (“non-increasing”), has been applied in the Superfund program

ee consecutive years of quarterly monitoring results demonstrating a statistically significant non-increasing trend at the 95 percent confidence level remaining below each constituent concentration standard.” This alternative approach, which would require the licensee to demonstrate that the trend line is either horizontal or decreasing (“non-increasing”), has been applied in the Superfund program. It has the clear advantage of accepting only trend lines that are not increasing, which can provide some additional confidence that the trend is not in a direction that could (eventually) threaten to exceed the constituent concentration standards.

However, based on discussions with the NRC, the agency responsible for implementing this rule after promulgation, it is clear that licensees may see increasing, but not statistically significant trends in constituent concentrations during stability monitoring. Consequently, the EPA opted to change the language to “no statistically significant increasing trend” to provide the NRC flexibility in addressing this specific scenario. Further, the EPA is concerned that specifying a non-increasing trend may introduce complications in applying statistical techniques, particularly when working from the hypothesis that there is no slope to the trend line. The level of natural variation present may itself forestall the ability to determine a non-increasing slope with the level of confidence the EPA believes necessary. The level of statistical significance associated with an increasing trend that would be unacceptable is left to the regulatory agency to determine based on site-specific conditions.

The EPA requests public comment on the proposed approach as well as the alternatives. Specifically, the EPA would like to know whether this language is sufficiently protective and whether there are any other practical approaches the Agency should consider as possible alternatives

ing trend that would be unacceptable is left to the regulatory agency to determine based on site-specific conditions.

In this proposal, the EPA has defined the long-term stability standards as a two-part test, with the following elements: (1) The licensee must provide an additional three consecutive years of quarterly monitoring data demonstrating no statistically significant increasing trend exceeding the constituent concentration standard for each applicable constituent at the 95 percent confidence level; and (2) the licensee must provide geochemical modeling and other analysis to demonstrate that constituent concentrations within the production zone will be met in the future. The regulatory agency would evaluate the modeling and other analysis and make a determination as to whether there is reasonable assurance that the applicable constituent concentration standards will continue to be met in the future. In this proposal, only after this determination has been made by the regulatory agency would the licensee cease long-term monitoring.

The three-year long-term monitoring period represents a different application of the RCRA paradigm than the 30-year post-closure monitoring. The three-year monitoring period is consistent with RCRA corrective action requirements, which can be seen as analogous with groundwater restoration at ISR sites. The Agency believes the three-year performance standard for the long term is appropriate to provide additional confidence in restoration of these sites and provides sufficient time to conduct a trend analysis, as well as being consistent with RCRA requirements of three years of monitoring to demonstrate no exceedance associated with corrective action

gous with groundwater restoration at ISR sites. The Agency believes the three-year performance standard for the long term is appropriate to provide additional confidence in restoration of these sites and provides sufficient time to conduct a trend analysis, as well as being consistent with RCRA requirements of three years of monitoring to demonstrate no exceedance associated with corrective action. The EPA finds that this alternative approach will provide the necessary protectiveness and is particularly responsive to industry comments regarding the potential costs associated with a 30-year monitoring period.

G. Corrective Action Program

The EPA originally proposed that facilities be required to take corrective action as soon as practicable but no later than 90 days after an excursion or exceedance is detected. The original proposal also required that the concentrations of constituents be returned to the constituent concentration standards “within the production zone and the maximum constituent level in adjacent aquifers” (see § 192.54(a) of the proposed rule). Groundwater monitoring for a period of at least three years after corrective action had been terminated was proposed with reference to the proposed monitoring requirements for the initial and long-term stability phases.

A few commenters supported the requirement to take corrective action as soon as practicable. However, most commenters disagreed with the original proposed requirement to require ISR facilities to implement a corrective action program within 90 days. One commenter was concerned the compliance costs would be high because the wellfield and associated equipment would have to be maintained at the ISR facility for many years in order for corrective action to be started within the required 90 days. Another commenter thought a longer time period was justified due to the low velocity of groundwater at ISR facilities

tive action program within 90 days. One commenter was concerned the compliance costs would be high because the wellfield and associated equipment would have to be maintained at the ISR facility for many years in order for corrective action to be started within the required 90 days. Another commenter thought a longer time period was justified due to the low velocity of groundwater at ISR facilities. This commenter asserted that additional time may be needed for drilling wells and installing pump and treat equipment, particularly during the long-term stability period when equipment has been removed. This commenter recommended a period of two years be allowed for implementing a corrective action program and stated that groundwater may move only 10 to 20 feet over this time period. Another commenter noted that the NRC already has regulations covering corrective action in 10 CFR part 40, Appendix A, Criterion 5D, which specify that a licensee has up to 18 months to implement a corrective action program. One commenter found the proposed requirements for groundwater monitoring confusing and questioned why the proposed rule referenced the initial and long-term stability monitoring requirements. This commenter thought the groundwater monitoring applied to excursions and questioned why additional monitoring was necessary for excursions occurring during the operational phase.

The EPA has made several changes to the corrective action requirements in this proposal. First, the EPA would require ISR facilities to begin (but not necessarily complete) corrective action no later than 60 days after an excursion or exceedance is detected. The EPA made this change to be consistent with the NRC's current practice for excursions. 16 Full implementation may

16 NRC (2003), “Standard Review Plan for In-Situ Leach Uranium Extraction License Applications http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1569/

in (but not necessarily complete) corrective action no later than 60 days after an excursion or exceedance is detected. The EPA made this change to be consistent with the NRC's current practice for excursions. 16 Full implementation may

16 NRC (2003), “Standard Review Plan for In-Situ Leach Uranium Extraction License Applications http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1569/.

Second, the EPA is acknowledging that corrective action in the initial stability phase may be different than in the long-term stability phase, as during the initial stability phase data are being collected to show the initial trend and may be more subject to fluctuation. One exceedance may be acceptable during the initial stability phase, but not for the long-term stability phase, without taking corrective action. The EPA is proposing the regulatory agency would have the authority to determine whether an exceedance truly warrants action or continued monitoring while the licensee is trying to establish the data trend during the initial stability phase. The need for action or monitoring during each phase of operation would be anticipated and addressed in the corrective action program. Whether or not the regulatory agency has determined that corrective action is necessary does not negate or affect the proposed initial stability standards requiring three consecutive years of quarterly monitoring results with no statistically significant increasing trends exceeding the constituent concentration standards at the 95 percent confidence level. The corrective action program would have to return the constituent concentrations to levels below the constituent concentration standards established by the regulatory agency.

tuent concentrations to levels below the constituent concentration standards established by the regulatory agency.

Finally, the EPA is proposing to change the groundwater monitoring provisions proposed for § 192.54(c) (80 FR 4187) to better reflect the requirements applicable to ISR facilities that experience exceedances of constituent concentration standards during the long-term stability phase. The EPA agrees with a commenter who stated that the proposed rule language for the groundwater monitoring requirements in § 192.54(c) could easily be misinterpreted. The change to the original proposed rule makes it explicit that corrective action is followed by another round of initial stability monitoring followed by long-term stability monitoring. Under this proposal, the ISR facility would need to first meet the three-year initial stability standards, and then meet the long-term stability standards of § 192.53(c)(3)(i) and (ii), before it is eligible to apply to the regulatory agency for approval to cease long-term stability monitoring. These changes to § 192.54(c) would not add any new requirements but simply clarify the requirements that were originally proposed.

H. Costs and Economic Impacts

1. Compliance Costs

Commenters expressed concern that the EPA had not considered the entire spectrum of legal, regulatory and other costs required to hold and preserve the ISR facility, lands and wellfields during the stability monitoring periods. The EPA reviewed and updated the economic analysis to incorporate estimated non-monitoring costs ( e.g., licensing, leasing fees, continued surety, maintenance) identified in the comments. Commenters also recommended that the EPA consult the ISR industry to better characterize costs, and the EPA requested additional information from some of the uranium recovery companies that had provided cost data during the public comment period to clarify the information provided

mated non-monitoring costs ( e.g., licensing, leasing fees, continued surety, maintenance) identified in the comments. Commenters also recommended that the EPA consult the ISR industry to better characterize costs, and the EPA requested additional information from some of the uranium recovery companies that had provided cost data during the public comment period to clarify the information provided. The additional cost information received from the uranium recovery companies was incorporated into the economic analysis. A listing of the non-monitoring costs that were identified in the comments and added to the revised analysis, along with a comparison of non-monitoring costs provided by industry and the average values used in the economic model, can be found in the economic analysis report (see sections 3.2 and 3.3). The addition of non-monitoring costs added $2,300 per acre to the modeled average facility costs excluding license and surety. The estimated total annualized incremental non-monitoring costs projected to be incurred by firms owning existing ISR facilities ranged between $0.1 million and $4.1 million, with total national non-monitoring costs of $7.6 million for all firms. All costs in the economic analysis have been adjusted from 2011 to 2015 dollars, as suggested by commenters.

Another concern expressed by commenters was that the EPA had not considered additional costs to self-funded regulatory programs, and that these costs would be passed along to the uranium recovery companies. The revised standards reflect the practices that have become more common between the NRC and ISR facilities; therefore, this proposal is not expected to add significant burden to regulatory programs.

Compliance for existing ISR facilities also concerned commenters. As in the proposal, § 192.52(a) of this proposal makes clear that these standards would not apply to wellfields that are currently in and remaining in restoration or stability monitoring

become more common between the NRC and ISR facilities; therefore, this proposal is not expected to add significant burden to regulatory programs.

Commenters also expressed concern that the costs of monitoring were not adequately reflected due to inaccurate assumptions for current monitoring requirements. The EPA adjusted the monitoring costs in the economic analysis based on guidance received from the NRC regarding current monitoring practices and requirements, as opposed to historical practices that were noted by some commenters as common to more developed ISR facilities. Also, a commenter noted that the rule discussion in the proposal preamble at 80 CFR 4186 (§ 192.53(a)(3) of the original proposal) required monitoring well locations outside of the monitoring well ring and that these costs were not included in the economic analysis. The proposal maintains the requirement in the original proposal for down-gradient monitoring wells outside the monitoring well ring where needed, and at the discretion of the regulating agency, especially when an adjacent aquifer is present. Initially, the EPA's proposal required monitoring at locations down-gradient from the wellfield in exempted aquifers. However, placement of down-gradient monitoring wells outside the well ring was not found to be common practice at existing sites and the EPA removed these wells from the cost model. The EPA also assumed in the proposal that monitoring and hydrogeologic and geochemical modeling requirements would allow most sites to demonstrate that groundwater conditions down-gradient of the wellfield would trap any mobilized constituents, thus ensuring that groundwater quality is protected

not found to be common practice at existing sites and the EPA removed these wells from the cost model. The EPA also assumed in the proposal that monitoring and hydrogeologic and geochemical modeling requirements would allow most sites to demonstrate that groundwater conditions down-gradient of the wellfield would trap any mobilized constituents, thus ensuring that groundwater quality is protected. Reference to the “exempted aquifer” has also been removed from this proposal, as discussed in section III.D of this preamble.

Comments were also received on the methodology used to extrapolate a cost per acre for operating ISR facilities based on a conceptual ISR unit, and while it was acknowledged that the method may be appropriate for fully developed ISR facilities, the commenters were concerned that this methodology may not capture the full costs of implementation for facilities in earlier stages of development. The EPA further reviewed and used available information from facility surety and license reports to estimate and account for the proposed and anticipated number of ISR units at each ISR facility that was included in the cost model.

In light of the adjustments described above, the EPA considers the estimated

2. Energy Impacts Summary

Several commenters noted the importance of nuclear power to shift the nation's reliance away from carbon-based energy resources and expressed concern that the proposed standards would reduce the viability of uranium recovery and continued development of nuclear energy. In response to these comments, the EPA reevaluated the incremental costs of the selected option to existing and planned ISR facilities, which further substantiated that this action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355, May 22, 2001)

hat the proposed standards would reduce the viability of uranium recovery and continued development of nuclear energy. In response to these comments, the EPA reevaluated the incremental costs of the selected option to existing and planned ISR facilities, which further substantiated that this action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355, May 22, 2001). The proposed standards, in large part, codify groundwater monitoring practices and requirements already being implemented at permitted operations; further, domestic uranium has historically provided less than 10 percent of total uranium supplied to civilian owners and operators (COOs) of nuclear power stations. Because the proposal would increase the costs of facilities that produce a relatively small share of uranium traded in U.S. markets, the EPA estimate that a $1.96 increase per pound in the cost of ISR uranium production would increase the price of uranium paid by COOs by only $0.11 per pound. Because nuclear generation provides a relatively small share of total domestic electricity, the $0.11 increase in the price of uranium would increase the price of electricity very little (less than 0.1 percent). Although the proposal would slightly increase the costs of domestic uranium production relative to international sources, this rule is not expected to directly and adversely affect productivity, competition or prices in the energy sector. For more information, please see section VI.H of this preamble and sections 5.3 and 6.9 of the document titled, “Economic Analysis: Revisions to the Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings Rule (40 CFR part 192),” available in Docket ID No. EPA-HQ-OAR-2012-0788.

o directly and adversely affect productivity, competition or prices in the energy sector. For more information, please see section VI.H of this preamble and sections 5.3 and 6.9 of the document titled, “Economic Analysis: Revisions to the Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings Rule (40 CFR part 192),” available in Docket ID No. EPA-HQ-OAR-2012-0788.

3. Groundwater Resource Impacts of Restoration

Several commenters expressed concern that the proposed rule would cause an unnecessary waste of groundwater resources beyond diminishing returns, due to prolonged additional restoration to satisfy the proposed requirement for 95 percent statistical confidence of groundwater stability. The EPA disagrees and believes that the 95 percent statistical confidence level is widely accepted and used in other environmental standards. For more information on the 95 percent confidence level, see section IV.D of the preamble.

One commenter stated that the EPA ignored its authority under CERCLA that allows the Agency to require former operators and their successors to clean up post-license termination, thereby unnecessarily increasing monitoring costs for ISR facilities. The EPA does not believe it is appropriate to rely upon expectations of future cleanup rather than make reasonable efforts to prevent groundwater contamination in the first place. The intent of this rule is to protect groundwater and prevent its degradation, thereby eliminating the need for remedial actions under CERCLA that, by the time discovered, could be far costlier. This approach is fully consistent with the EPA's Groundwater Protection Strategy, which emphasizes pollution prevention over remediation. Also, commenters asserted that the groundwater modeling was inadequate, and flawed inputs were used to estimate the duration of remediation to clean up a plume after facility closure

edial actions under CERCLA that, by the time discovered, could be far costlier. This approach is fully consistent with the EPA's Groundwater Protection Strategy, which emphasizes pollution prevention over remediation. Also, commenters asserted that the groundwater modeling was inadequate, and flawed inputs were used to estimate the duration of remediation to clean up a plume after facility closure. The EPA understands that the contaminant transport models used to estimate costs of remediating a contaminant plume are simplistic, the inputs used are based on limited ISR facility data, and selected parameterizations are based on assumptions. Nevertheless, the flow model provides a reasonable estimate for the duration of an illustrative general pump and treat remediation scenario, based on the EPA's extensive pump and treat remediation experience under CERCLA and other remedial programs, and, upon review, the models and inputs were determined to be adequate to illustrate potential cost savings for purposes of the economic analysis.

I. Other Miscellaneous Changes

1. Clarification of “Operational Phase”

In the original proposal, the EPA defined the operational phase of an ISR facility as “the time period during which uranium extraction by in-situ recovery occurs” and noted that “operations end when the operator permanently ceases injection of lixiviant and recovery of uranium-bearing solution for processing” (see 80 FR 4160). However, the EPA notes there are periods when the ISR facility is not actively recovering uranium for various reasons ( e.g., market conditions), but production is intended to resume when conditions are more favorable. These periods are sometimes referred to as “standby” by operators. In the original proposal, the EPA expressed the view that it would not be appropriate to allow a standby period for ISR facilities if the gradient within the wellfield is not being maintained, and that stopping the extraction cycle should require the operator to enter the restoration phase

resume when conditions are more favorable. These periods are sometimes referred to as “standby” by operators. In the original proposal, the EPA expressed the view that it would not be appropriate to allow a standby period for ISR facilities if the gradient within the wellfield is not being maintained, and that stopping the extraction cycle should require the operator to enter the restoration phase. Commenters acknowledged that ISR facilities can experience extended periods of standby and noted that active pumping during these periods is necessary to prevent contamination of groundwater in areas outside the production zone. One commenter recommended the EPA minimize the amount of time during which an ISR facility in standby is not pumping. Other commenters thought ISR facilities entering standby should be required to initiate restoration and recommended that the EPA require ISR facilities to commence restoration within a specified time period after ceasing active uranium recovery.

The EPA agrees with the commenters who said ISR facilities must be responsible for ensuring that lixiviant and constituents do not migrate outside of the production zone during standby periods. The EPA disagrees with the commenter who suggested ISR facilities that temporarily cease operations should be required to commence restoration. The EPA agrees, however, that during standby periods the migration of constituents mobilized by the prior injection of lixiviant may continue even if the decision is made to stop extracting uranium. Excursions beyond the production zone are more likely to occur if the hydraulic gradient within the wellfield is not maintained. For this reason, the EPA considers standby to be part of the operational phase, and facilities should not cease pumping during standby periods since it is important that an inward hydraulic gradient is maintained during these periods. For this reason, the EPA is proposing that all requirements applicable to the operational phase remain in effect during these standby periods

ield is not maintained. For this reason, the EPA considers standby to be part of the operational phase, and facilities should not cease pumping during standby periods since it is important that an inward hydraulic gradient is maintained during these periods. For this reason, the EPA is proposing that all requirements applicable to the operational phase remain in effect during these standby periods. Provided the licensee complies with the operational phase monitoring and corrective action requirements in the proposed rule, ISR facilities in standby would not need to enter restoration because groundwater in areas surrounding the production zone will be afforded the same level of

2. Changes to the Definition of “Point(s) of Compliance”

As stated in the original proposal, during the restoration phase, the definition of “point(s) of compliance” may include “monitoring, injection, and extraction wells in the production zone” (see 80 FR 4184). Points of compliance during the initial stability and long-term stability phases should include locations within the former production zone, including existing monitoring, injection and extraction wells. To clarify these requirements, in this proposal, the EPA revised the definition of “point(s) of compliance” to indicate that excursion monitoring wells are considered points of compliance during all phases of ISR operation and that during the initial and long-term stability monitoring phases, points of compliance should also include locations, identified by the regulatory agency, where a potential receptor can come into contact with contaminated groundwater. The EPA is specifically requesting comment on the definition of “point(s) of compliance” and how it is applied. Again, the EPA is requesting comment on the definition of point of exposure and conceptual framework for establishing ACLs.

compliance should also include locations, identified by the regulatory agency, where a potential receptor can come into contact with contaminated groundwater. The EPA is specifically requesting comment on the definition of “point(s) of compliance” and how it is applied. Again, the EPA is requesting comment on the definition of point of exposure and conceptual framework for establishing ACLs.

IV. Responses to Other Significant Comments That Did Not Result in Changes to the Original Proposal

The EPA carefully reviewed and considered comments from a wide range of different groups in preparing this proposal. As discussed in section III of this preamble, the EPA modified and clarified various aspects of the proposed rule based on the information and views provided, including comments on the original proposal. However, not all comments resulted in modifications to the proposed rule. Those significant comments that did not result in changes, together with the EPA's responses, are summarized in this section of the preamble.

A. Authority To Set Generally Applicable Standards

Some commenters thought the proposed rules were legally invalid and felt the EPA was overreaching its authority under UMTRCA by proposing standards that are too detailed and prescriptive. The commenters argued the EPA was redefining what UMTRCA established as the EPA's role to set general standards while making the NRC responsible for implementing those standards through its licensing process. These commenters believe that UMTRCA limits the EPA's authori

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