[Federal Register Volume 80, Number 16 (Monday, January 26, 2015)]
[Proposed Rules]
[Pages 4156-4187]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-00276]



[[Page 4155]]

Vol. 80

Monday,

No. 16

January 26, 2015

Part III





Environmental Protection Agency





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40 CFR Part 192





 Health and Environmental Protection Standards for Uranium and Thorium 
Mill Tailings; Proposed Rule

Federal Register / Vol. 80 , No. 16 / Monday, January 26, 2015 / 
Proposed Rules

[[Page 4156]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 192

[EPA-HQ-OAR-2012-0788; FRL-9909-20-OAR]
RIN 2060-AP43


Health and Environmental Protection Standards for Uranium and 
Thorium Mill Tailings

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to add 
new health and environmental protection standards to regulations 
promulgated under the Uranium Mill Tailings Radiation Control Act of 
1978 (``UMTRCA'' or ``the Act''). The proposed standards will regulate 
byproduct materials produced by uranium in-situ recovery (ISR), 
including both surface and subsurface standards, with a primary focus 
on groundwater protection, restoration and stability. ISR has a greater 
potential to directly affect groundwater than does conventional 
milling. Therefore, by explicitly addressing the most significant 
hazards represented by ISR activities, these proposed standards are 
intended to address the shift toward ISR as the dominant form of 
uranium recovery that has occurred since the standards for uranium and 
thorium mill tailings were initially promulgated in 1983. The general 
standards proposed today, when final, will be implemented by the 
Nuclear Regulatory Commission (NRC). This action also proposes to amend 
specific provisions in the current Health and Environmental Protection 
Standards for Uranium and Thorium Mill Tailings 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 that have been identified since the 
1983 promulgation.

DATES: Comments must be received on or before April 27, 2015.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2012-0788, by one of the following methods:
    <bullet> www.regulations.gov: Follow the on-line instructions for 
submitting comments.
    <bullet> Email: <a href="/cdn-cgi/l/email-protection#08692569666c257a256c676b636d7c486d7869266f677e"><span class="__cf_email__" data-cfemail="a4c589c5cac089d689c0cbc7cfc1d0e4c1d4c58ac3cbd2">[email protected]</span></a>.
    <bullet> Fax: 202-566-9744.
    <bullet> Mail: Air and Radiation Docket, Environmental Protection 
Agency, Mailcode: 2822T, 1200 Pennsylvania Ave. NW., Washington, DC 
20460.
    <bullet> 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. 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 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 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, 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 EPA cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, 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 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. 
NW., Washington, DC 20460; telephone number: 202-343-9286; fax number: 
202-343-2304; email address: <a href="/cdn-cgi/l/email-protection#c89aa7bbada6abbaa9a6bcb2e6a1a6afbaa1ac88adb8a9e6afa7be"><span class="__cf_email__" data-cfemail="9bc9f4e8fef5f8e9faf5efe1b5f2f5fce9f2ffdbfeebfab5fcf4ed">[email protected]</span></a>.
    Executive Summary: The Environmental Protection Agency (EPA) is 
proposing to add new health and environmental protection standards to 
regulations promulgated under the Uranium Mill Tailings Radiation 
Control Act of 1978 (``UMTRCA'' or ``the Act''). The proposed standards 
will regulate byproduct materials produced by uranium in-situ recovery 
(ISR), including both surface and subsurface standards, with a primary 
focus on groundwater protection, restoration and stability. ISR has a 
greater potential to directly affect groundwater than does conventional 
milling. Therefore, by explicitly addressing the most significant 
hazards represented by ISR activities, these proposed standards are 
intended to address the shift toward ISR as the dominant form of 
uranium recovery that has occurred since the standards for uranium and 
thorium mill tailings were initially promulgated in 1983. The legal 
authority for this action is in Section 275 of the Atomic Energy Act 
(AEA) of 1954, as amended by Section 206 of the Uranium Mill Tailings 
Radiation Control Act (UMTRCA) of 1978. Health and environmental 
protection standards established by EPA under UMTRCA are implemented by 
NRC. See 42 U.S.C. 2022(b) and (d).
    This action also proposes to amend specific provisions in the 
current Health and Environmental Protection Standards for Uranium and 
Thorium Mill Tailings 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 
that have been identified since the 1983 promulgation.
    The major provisions of today's proposal include the following:
    <bullet> We are proposing to add an additional subpart within 40 
CFR part 192 to explicitly address groundwater protection at uranium 
ISR operations. A new subpart F is being proposed that would set 
standards that would apply to uranium ISR facilities only. The overall 
purpose of this subpart is to address the most significant hazards 
represented by

[[Page 4157]]

ISR activities. This subpart adds the following:
    1. A section on applicability--Sec.  192.50 Applicability--that 
specifies the subpart will apply to the management of uranium byproduct 
materials during and following the processing of uranium ores using ISR 
methods.
    2. A section containing definitions--Sec.  192.51 Definitions and 
cross-references.
    3. A section--Sec.  192.52 Standards--in which EPA proposes to 
specify the minimum 13 constituents for which groundwater protection 
standards must be met. The list includes the following: Arsenic, 
barium, cadmium, chromium, lead, mercury, selenium, silver, nitrate (as 
N), molybdenum, combined radium-226 and radium-228, uranium (total), 
and gross alpha-particle activity (excluding radon and uranium).
    4. A section discussing monitoring requirements--Sec.  192.53 
Monitoring programs--that details the specific requirements of 
monitoring programs to be conducted during the preoperational, 
operational, restoration, stability and long-term stability phases.
    5. A section establishing requirements for corrective actions--
Sec.  192.54 Corrective action program.
    6. A section detailing the effective date of the new subpart--Sec.  
192.55--Effective date.
    <bullet> As noted above, we are also proposing to amend certain 
provisions within the existing 40 CFR part 192 to address a ruling of 
the Tenth Circuit Court of Appeals, delete reference to an outdated 
standard and correct minor technical and typographical errors.
    The costs and benefits of this rulemaking are described briefly in 
the tables presented below. Costs quantified in Table 2 address costs 
of the rule that reflect appropriate characterization of the background 
data, and then ensuring that: (1) The post-operational groundwater is 
restored to that of the initial groundwater conditions and (2) the 
post-restoration groundwater conditions will remain stable.
    The proposed rule requires affected facilities to monitor 
groundwater for a longer period of time compared to current practice 
(estimated to be 9.5 additional years if geochemical modeling indicates 
that conditions will remain stable, and estimated 32.5 additional years 
if long-term stability monitoring continues for 30 years. The major 
costs associated with the proposed rule are the costs of these 
monitoring activities. National total annualized incremental costs of 
the proposed rule, based on likely implementation represented by the 
average cost of 30-year long-term stability monitoring with geochemical 
modeling to shorten the duration, is $13.5 million (in 2011 dollars), 
as shown in Table 2 below. EPA also examined potential impacts on small 
businesses that own and operate ISR operations. Using existing owner 
companies as examples of the firms that may own ISR operations subject 
to the proposed rule, EPA found that the estimated costs of complying 
with the proposed rule are 0.6% to 1.7% of estimated 2015 revenues for 
three small firms that own ISR operations. Because costs do not exceed 
2% of estimated sales, and because EPA projects that fewer than 10 
small businesses will be affected by the rule at any given time, EPA 
concluded that the proposed rule would not result in significant 
impacts for a substantial number of small entities. For information on 
how EPA estimated these costs, see Section 3 and Appendix D of the 
Economic Analysis.
    EPA conducted a qualitative assessment of the benefits of the 
proposed rule. EPA recognizes that groundwater is a valuable resource, 
and is becoming more valuable as groundwater use increases. While the 
aquifers in the vicinity of ISR operations are currently providing 
little extractive value (because of their locations and, for some 
areas, the fact that groundwater quality is low), in future years these 
resources may have increased value. A recent analysis (Poe et al, 2001) 
estimated the value to today's households of protecting groundwater for 
future use ranged from $531 to $736 per household. For this reason, EPA 
believes it is necessary to take a longer view of groundwater 
protection than taken in the past. Currently, monitoring groundwater 
conditions after restoration is typically conducted for a short period 
of time (EPA assumes 6 months for cost estimate purposes), which may 
not be long enough to detect instability in groundwater conditions. 
EPA's proposed rule requires a 30 year long-term stability monitoring 
period, which may be shortened if geochemical modeling demonstrates 
that conditions in the restored wellfield will remain stable over time.
    The proposed rule will reduce the risk of undetected excursions of 
pollutants into adjacent aquifers. This in turn will reduce the human 
health risks that could result from exposures to radionuclides in well 
water used for drinking or agriculture in areas located down-gradient 
from an ISR. Because radionuclides are human carcinogens, the main 
health risk averted would be cancer. There is a benefit (estimated to 
be at least $8 million per premature death avoided) of reducing cancer 
deaths, but because we were unable to estimate how many cancer deaths 
would be averted, or when they would occur, EPA is unable to quantify 
this benefit.
    In addition to avoiding human health impacts, the proposed rule has 
the potential to detect excursions sooner and thus enable a faster 
remedial response. Because plumes detected during long-term stability 
monitoring would be smaller, costs of remediation would be potentially 
much lower. For a model mine unit, EPA estimated the averted 
remediation costs to range from $8.8 million to more than $500 million. 
EPA is unable to extrapolate this estimate to a national value, because 
we do not have a basis for estimating which, if any, wellfields would 
experience an undetected contaminant plume in the absence of the 
proposed rule.

 Table 1--Characterization of the Costs and Benefits of 40 CFR Part 192,
                                Subpart F
------------------------------------------------------------------------
                   Costs                              Benefits
------------------------------------------------------------------------
Annualized monitoring costs ranging from    Protection of groundwater
 $12.5 to $14.1 million.                     quality.
Maintenance of financial assurance for up   Possible protection of
 to 30 additional years per facility.        surface water quality.
                                            Potentially reduced risk of
                                             exposure of human or
                                             ecological receptors to
                                             radiological pollutants.
                                            Potentially reduced human
                                             health impacts, including
                                             cancer.
                                            Reduced remediation cost
                                             savings ($8.8 million to
                                             $560 million for CMU).
------------------------------------------------------------------------


[[Page 4158]]


Table 2--Summary of the Costs and Benefits of 40 CFR Part 192, Subpart F
                              with Options
                       [millions of 2011 dollars]
------------------------------------------------------------------------
                                  Capital     Annual
          Requirement              cost        cost        Net benefit
------------------------------------------------------------------------
30 years with geochemical        \a\ $25.2       $13.5  Not Quantified.
 modeling.
30 Years, no shortening.......        19.3        15.1
------------------------------------------------------------------------
\a\ Capital costs are higher for the geochemical modeling option because
  more wells would be required.


SUPPLEMENTARY INFORMATION: 
    Outline. The information in this preamble is organized as follows:

I. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments to EPA?
    1. Submitting CBI
    2. Tips for Preparing Your Comments
    C. When would a public hearing occur?
    D. What documents are referenced in today's proposal?
    E. Acronyms and Abbreviations
    F. Definitions
II. Background Information
    A. What is the scope of this action?
    B. Uranium Extraction
    1. Conventional Mining and Milling
    2. Heap Leach
    3. In-Situ Recovery (ISR)
    C. What is the statutory authority for the proposed amendments?
    D. What are the existing requirements under 40 CFR part 192?
    E. Why does EPA believe new standards are necessary?
    1. What are the environmental impacts of uranium ISR?
    2. What analysis has EPA done to support the proposal?
    3. What came out of the Advisory from EPA's Science Advisory 
Board?
    4. What efforts has the Nuclear Regulatory Commission taken 
recently?
    F. What other EPA statutes and regulations are relevant?
    1. Safe Drinking Water Act (SDWA)
    2. Clean Water Act (CWA)
    3. Clean Air Act (CAA)
    4. Resource Conservation and Recovery Act (RCRA)
III. Summary of Today's Proposal
    A. Proposed Standards--Subpart F
    1. Proposal of New Subpart--Subpart F--Public Health, Safety and 
Environmental Protection Standards for Byproduct Materials Produced 
by Uranium In-situ Recovery
    2. Addition of New Section on Applicability--Sec.  192.50 
Applicability
    3. Addition of New Section Containing Definitions--Sec.  192.51 
Definitions and Cross-References
    4. Addition of New Section Detailing Standards--Sec.  192.52 
Standards
    5. Addition of New Section Discussing Monitoring Requirements--
Sec.  192.53 Monitoring Programs
    6. Addition of New Section Discussing Requirements for 
Corrective Actions--Sec.  192.54 Corrective Action Program
    7. Addition of New Section Detailing the Effective Date of the 
New Subpart--Sec.  192.55--Effective Date
    B. Other Proposed Amendments
    1. Revision to Subpart C--Implementation
    2. Revision to Subpart D--Standards for the Management of 
Uranium Byproduct Materials
IV. What is the rationale for today's proposal?
    A. How does today's proposal relate to existing 40 CFR part 192?
    B. What groundwater protection standards are we proposing for 
ISR facilities?
    1. Generally Applicable Groundwater Standards
    2. Alternate Concentration Limits (ACLs)
    C. Adequate Characterization of Groundwater Prior to Uranium 
Recovery
    1. Establishing Restoration Goals
    D. Excursions
    E. Long-Term Stability Monitoring
    1. Thirty-Year Long-Term Stability Monitoring Period, With 
Provisions for Shortening That Time Period
    2. What other options did EPA consider for the long-term 
stability monitoring period?
    a. Required Thirty-Year Long-Term Stability Monitoring Period
    b. Narrative Standard With No Fixed Monitoring Period
    3. How will groundwater stability be determined?
    a. What do we propose for determining stability?
    b. Where will the determination of stability be made?
    F. Institutional Control
    G. Other Proposed Amendments
    1. Judicial Decision
    2. Miscellaneous Updates and Corrections
    a. Outdated Cross-Reference
    b. Technical Corrections
V. Summary of Environmental, Cost and Economic Impacts
    A. What are the impacts to groundwater?
    B. What are the benefits of avoiding impacts to groundwater?
    C. What are the cost impacts?
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. General Information

A. Does this action apply to me?

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

------------------------------------------------------------------------
                                      NAICS      Examples of regulated
             Category                code \1\           entities
------------------------------------------------------------------------
Industry:
    Uranium Ores Mining and/or         212291  Facilities that extract
     Beneficiating.                             or concentrate uranium
                                                from any ore processed
                                                primarily for its source
                                                material content.
    Leaching of Uranium, Radium or     212291  Facilities that extract
     Vanadium Ores.                             or concentrate uranium
                                                from any ore processed
                                                primarily for its source
                                                material content.
------------------------------------------------------------------------
\1\ North American Industry Classification System.


[[Page 4159]]

    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?

    1. Submitting CBI. Do not submit CBI information to 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 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.
    2. Tips for preparing your comments. When submitting comments, 
remember to:
    <bullet> Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
    <bullet> 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.
    <bullet> Explain why you agree or disagree, suggest alternatives, 
and substitute language for your requested changes.
    <bullet> Describe any assumptions and provide any technical 
information and/or data that you used.
    <bullet> If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    <bullet> Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    <bullet> Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
    Make sure to submit your comments by the comment period deadline 
identified.

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 25, 2015, we will hold a 
public hearing. If you are interested in attending the public hearing, 
contact Mr. Anthony Nesky at (202) 343-9597 to verify that a hearing 
will be held. If a public hearing is held, we will announce the date, 
time and venue on our Web site at http://www.epa.gov/radiation/tenorm/40CFR192.html.

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

    We refer to a number of documents that provide supporting 
information for our uranium and thorium mill tailings standards. All 
documents relied upon by EPA in regulatory decision making may be found 
in our 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,'' 
Environmental Protection Agency, 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),'' Environmental 
Protection Agency, 2014.
EPA 530/R-09-007 ``Statistical Analysis of Groundwater Monitoring 
Data at RCRA Facilities--Unified Guidance,'' Environmental 
Protection Agency, 2009.

E. Acronyms and Abbreviations

    The following acronyms and abbreviations are used in this document:

ACL--alternate concentration limit
AEA--Atomic Energy Act
BID--Background information document
CAA--Clean Air Act
CWA--Clean Water Act
CBI--Confidential Business Information
CFR--Code of Federal Regulations
DOE--U.S. Department of Energy
EIA--economic impact analysis
EO--Executive Order
EPA--U.S. Environmental Protection Agency
FR--Federal Register
ISR--in-situ recovery, also known as in-situ leaching (ISL)
l--liter
MCLs--Maximum Contaminant Levels
mg--milligram
MOU--Memoranda of Understanding
N--nitrate
NRC--U.S. Nuclear Regulatory Commission
NTTAA--National Technology Transfer and Advancement Act
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
UIC--underground injection control
U.S.--United States
USD--United States dollar
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
WL--Working Level

F. Definitions

    The following terms are used in this document:

------------------------------------------------------------------------
         Terminology                           Definition
------------------------------------------------------------------------
Adjacent Aquifer.............  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.
Alternate Concentration Limit  Concentration limit approved by the
 (ACL).                         regulatory agency for a groundwater
                                constituent that has not been restored
                                to its restoration goal after best
                                practicable restoration activities have
                                been completed following the process
                                prescribed in 40 CFR 192.52(c)(2) thru
                                192.52(c)(5).
Aquifer......................  A geological ``formation,'' group of
                                formations, or part of a formation that
                                is capable of yielding a significant
                                amount of water to a well or spring. See
                                40 CFR 144.3.
Aquitard.....................  A confining bed that retards but does not
                                prevent the flow of water to or from an
                                adjacent aquifer.
Background...................  The condition of groundwater, including
                                the radiological and non-radiological
                                constituent concentrations, in the
                                exempted aquifer, adjacent aquifers, and
                                in both overlying and underlying
                                aquifers, prior to the beginning of ISR
                                operations. The background groundwater
                                constituent concentrations in the
                                production zone prior to the beginning
                                of ISR operations is commonly referred
                                to by the industry and regulatory bodies
                                as the ``baseline.''
Beneficiation................  The initial attempt at liberating and
                                concentrating a valuable mineral from
                                extracted ore. This is typically
                                performed by employing various crushing,
                                grinding, and froth flotation
                                techniques.
Byproduct Material...........  See ``Uranium Byproduct Material.''
Constituent..................  A detectable component within the
                                groundwater.
Exceedance...................  An exceedance has occurred when, during
                                stability or long-term stability
                                monitoring, a groundwater protection
                                standard is exceeded at any point of
                                compliance well.

[[Page 4160]]

 
Excursion....................  The movement of fluids containing uranium
                                byproduct material from an ISR
                                production zone into surrounding
                                groundwater. An excursion is considered
                                to have occurred when, during
                                operational or restoration phase
                                monitoring, any two indicator parameters
                                (e.g., chloride, conductivity, total
                                alkalinity) exceed their respective
                                upper control limits in any overlying,
                                underlying, or perimeter monitoring
                                well. Horizontal excursions refer to the
                                lateral movement of the water, while
                                vertical excursions indicate movement of
                                water through aquitards above or below
                                the production zone aquifer.
Excursion Monitoring Well....  Wells located around the perimeter of the
                                production zone (horizontal excursion
                                wells) and in overlying and underlying
                                aquifers (vertical excursion wells),
                                which are used to detect any excursions
                                from the production zone. Excursion
                                monitoring wells can serve as the
                                ``point(s) of compliance'' during all
                                phases of ISR.
Exempted Aquifer.............  An ``aquifer,'' or its portion, that
                                meets the criteria in the definition of
                                ``underground source of drinking water''
                                in 40 CFR 144.3, but which has been
                                exempted according to the procedures in
                                40 CFR 144.7. See 40 CFR 144.3.
Extraction Well..............  Well used to extract uranium enriched
                                solutions from the ore-bearing aquifer;
                                also known as a ``Production Well.''
                                Extraction and injection wells may be
                                converted from one use to the other.
Facility.....................  See ``Uranium Recovery Facility.''
Groundwater..................  Water below the land surface in a zone of
                                saturation. See 40 CFR 144.3.
Indicator Parameter..........  A constituent, such as chloride,
                                conductivity, or total alkalinity, whose
                                ``upper control limit'' is used to
                                identify an excursion. Indicator
                                parameters are not contaminants, but
                                relate to geochemical conditions in
                                groundwater.
Injection Well...............  A well into which fluids are being
                                injected. See 40 CFR 144.3.
In-Situ Recovery (ISR).......  A method of extraction 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
                                body. The process does not require the
                                extraction of ore from the ground. The
                                lixiviant is injected, passes through
                                the ore body, mobilizes the uranium, and
                                the uranium-bearing solution is pumped
                                to the surface from extraction wells.
                                The pregnant leach solution is processed
                                to extract the uranium.
Ion Exchange.................  The process in which ions are exchanged
                                between a solution and an insoluble
                                solid.
Listed Constituent...........  One of the thirteen groundwater
                                constituents specified in Table 1 to
                                subpart F of part 192.
Lixiviant....................  A liquid medium used to recover uranium
                                from underground ore bodies through in-
                                situ recovery. This liquid medium
                                typically contains native groundwater
                                and an added oxidant, such as oxygen and/
                                or hydrogen peroxide, as well as sodium
                                carbonate/bicarbonate or carbon dioxide.
                                The lixiviant is introduced through
                                injection wells into the ore body to
                                mobilize the uranium. The resulting
                                solution is then pumped via extraction
                                wells to the surface, where the uranium
                                is recovered from the solution for
                                further processing, after which the
                                lixiviant may be re-injected.
Long-Term Stability Phase....  The period after the groundwater
                                protection standards have been met, as
                                determined by the regulatory agency.
Maximum Constituent            The maximum permissible level of a
 Concentration.                 constituent in groundwater, as specified
                                in Table 1 to subpart A of part 192.
Maximum Contaminant Level      The maximum permissible level of a
 (MCL).                         contaminant in water which is delivered
                                to any user of a public water system.
                                See 40 CFR 141.2.
Mobilization.................  Increasing the migration of constituents
                                in groundwater by various chemical
                                treatments.
Monitoring Wells.............  Wells used to obtain groundwater levels
                                and water samples for the purpose of
                                determining the hydrologic regime and
                                the amounts, types, and distribution of
                                constituents in the groundwater. Wells
                                are located in the production zone,
                                around the perimeter of the production
                                zone (horizontal excursion monitoring
                                wells), and in overlying and underlying
                                aquifers (vertical excursion monitoring
                                wells).
Operational Phase............  The time period during which uranium
                                extraction by in-situ recovery occurs.
                                Operations begin when injection of
                                lixiviant starts; operations end when
                                the operator permanently ceases
                                injection of lixiviant and recovery of
                                uranium-bearing solution.
Ore..........................  The naturally occurring material from
                                which a mineral or minerals of value
                                (e.g., uranium) can be extracted.
Overlying Aquifer............  An aquifer that is immediately vertically
                                shallower than (i.e., directly above)
                                the production zone aquifer.
Point(s) of Compliance.......  Site-specific location(s) where
                                groundwater protection standards must be
                                met. During all phases of ISR, excursion
                                monitoring wells can serve as the points
                                of compliance; during the restoration,
                                stability and long-term stability
                                phases, points of compliance may also
                                include monitoring, injection and
                                extraction wells in the production zone,
                                as determined by the regulatory agency.
Point(s) of Exposure.........  Intersection of a vertical plane with the
                                boundary of the exempted aquifer.
Precipitate..................  To separate a substance (such as uranium)
                                out of a solution as a solid.
Preoperational Monitoring....  Measurement of groundwater conditions in
                                the production zone, and in the
                                groundwater up and down gradient from
                                the production zone, as well as in
                                overlying and underlying aquifers, prior
                                to the operational phase.
Production Zone..............  The portion of the aquifer in which ISR
                                activities occur. The production zone
                                lies within the wellfield.
Regulatory Agency............  The Nuclear Regulatory Commission (NRC)
                                or an Agreement State.
Restoration (Act of).........  The process of returning groundwater
                                quality to preoperational conditions for
                                the purpose of achieving restoration
                                goal values for identified constituents.
Restoration Goal.............  A concentration limit for an identified
                                constituent in groundwater after
                                restoration has occurred. The limit is
                                obtained from the most protective
                                regulatory standards in 40 CFR 141.62,
                                141.66, 141.80, 143.3, 264.94, and Table
                                1 to subpart A of this part, and from
                                preoperational background levels in the
                                wellfield, whichever is higher.
Restoration Phase............  The period immediately after lixiviant
                                injection permanently ceases, during
                                which restoration activities occur.
Site.........................  The land or water area where any facility
                                or activity is physically located or
                                conducted, including adjacent land used
                                in connection with the facility or
                                activity. See 40 CFR 144.3.
Stability Phase..............  The period after the restoration phase
                                when groundwater protection standards
                                are met and monitored to test for
                                temporal stability.
Solubilize...................  To make a substance (such as uranium)
                                soluble or more soluble.
Underground Source of          An aquifer or its portion: (a)(1) Which
 Drinking Water (USDW).         supplies any public water system; or (2)
                                Which contains a sufficient quantity of
                                groundwater 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. See 40 CFR
                                144.3.
Underlying Aquifer...........  An aquifer that is immediately vertically
                                deeper (i.e., directly below) than the
                                production zone aquifer.

[[Page 4161]]

 
Upper Control Limit (UCL)....  Preoperational concentrations of
                                indicator parameters in horizontal and
                                vertical excursion monitoring wells, as
                                determined by the regulatory agency and
                                contained in the license.
Uranium Byproduct Material...  Waste produced by the extraction or
                                concentration of uranium from any ore
                                processed primarily for its source
                                material content. Ore bodies depleted by
                                uranium ISR operations and which remain
                                underground do not constitute ``uranium
                                byproduct material.''
Uranium Recovery Facility....  A facility licensed to process uranium
                                ores for the purpose of recovering
                                uranium and to manage uranium byproduct
                                materials that result from processing of
                                ores. Common names for these facilities
                                include, but are not limited to, the
                                following: a conventional uranium mill,
                                an in-situ recovery (or leach) facility,
                                and a heap leach facility or pile.
Wellfield....................  The area of an ISR operation that
                                encompasses the array of injection,
                                extraction, and monitoring wells and
                                interconnected piping employed in the
                                uranium in-situ recovery process. The
                                area of the wellfield exceeds that of
                                the production zone.
------------------------------------------------------------------------

II. Background Information

A. What is the scope of this action?

    In 1983, EPA originally promulgated regulations at 40 CFR part 192, 
Health and Environmental Protection Standards for Uranium and Thorium 
Mill Tailings, in response to the statutory requirements of the Atomic 
Energy Act of 1954, as amended by the Uranium Mill Tailings Radiation 
Control Act of 1978 (UMTRCA). These standards have been amended several 
times, most recently in 1995, with the addition of standards to correct 
and prevent contamination of groundwater beneath and in the vicinity of 
inactive uranium processing sites.\1 2\ Pursuant to UMTRCA, our 
standards have been implemented by the Department of Energy (DOE) at 
inactive uranium milling sites and nearby contaminated ``vicinity 
properties'' managing residual radioactive material and by the Nuclear 
Regulatory Commission (NRC) or NRC Agreement States at active sites 
managing byproduct material.\3 4\
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    \1\ See 42 U.S.C. 7911(6) for the definition of a ``processing 
site.''
    \2\ See 60 FR 2854 (January 11, 1995) and 58 FR 60340 (November 
15, 1993).
    \3\ Byproduct material includes the tailings or wastes produced 
by the extraction or concentration of uranium from any ore processed 
primarily for its source material content. AEA section 11e.(2), 42 
U.S.C. 2014(e)(2).
    \4\ Under Section 274 of the AEA, the NRC may enter into an 
agreement with a State for discontinuance of the NRC's regulatory 
authority and the State's assumption of regulatory authority over 
specified radioactive materials and activities. The NRC must review 
and find the State's regulatory program is adequate to protect 
public health and safety and compatible with the NRC's regulatory 
program before entering into the Section 274 agreement. The NRC 
continues oversight responsibilities of the Agreement State's 
regulatory program through the Integrated Materials Performance 
Evaluation Program (IMPEP).
---------------------------------------------------------------------------

    Today's proposal is limited to the following changes. We are 
proposing to add an additional subpart within 40 CFR part 192 to 
explicitly address groundwater protection at uranium ISR operations. We 
are also proposing to amend certain provisions within the existing 40 
CFR part 192 to address a ruling of the Tenth Circuit Court of Appeals, 
delete reference to an outdated standard and correct minor technical 
and typographical errors. We request public comment only on these 
proposed standards and amendments. We are not requesting, and will not 
respond to, public comments on any other 40 CFR part 192 provisions 
since they are beyond the scope of today's proposal.

B. Uranium Extraction

    The major deposits of uranium ores in the United States are located 
in the Colorado Plateau, the Wyoming Basin, the Texas Coastal Plain, 
and Nebraska. Recovery and processing of these ores have historically 
occurred by one of three methods: (1) Conventional mining and milling 
operations; (2) heap leach operations; and (3) in-situ (i.e., in place) 
recovery. Below we present a brief explanation of these uranium 
recovery methods.
1. Conventional Mining and Milling
    Conventional mining and milling is one of the primary recovery 
methods currently used to extract uranium from uranium-bearing ore in 
much of the world and was formerly the predominant means of obtaining 
uranium in the United States. ``Remoteness from populated areas'' and 
``isolation of contaminants from groundwater'' are key considerations 
in selecting mill locations under current siting criteria found in NRC 
regulations.\5\ Only one conventional mill in the United States is 
currently operating; all others are in standby status, in 
decommissioning (closure) or have already been decommissioned.
---------------------------------------------------------------------------

    \5\ See 10 CFR part 40, Appendix A, Criterion 1.
---------------------------------------------------------------------------

    Conventional uranium mines are either open-pit operations, where 
large volumes of uranium bearing material are excavated, or underground 
mines, where the uranium-bearing ore is extracted via mined openings 
into the subsurface. The extracted ore is then moved to the milling 
operation where the uranium is extracted by chemical treatments of the 
ore. The ores are crushed mechanically and then leached at the milling 
site. In most cases, sulfuric acid is the leaching agent, but alkaline 
solutions can also be used to leach the uranium, generally extracting 
90 to 95 percent of the uranium from the crushed ore.
    The mill then processes the uranium from the solution by solvent 
extraction using organic chemicals, or by an ion exchange process using 
resins designed to extract the uranium from the leaching solutions used 
to remove uranium from the crushed ore, then further extracts, 
precipitates, and finally dries the recovered uranium to produce a 
uranium oxide material, called ``yellowcake'' because of its yellowish 
color.\6\ Finally, the yellowcake is packaged in special 55-gallon 
drums and transported to uranium conversion, enrichment and fuel 
fabrication facilities to produce fuel for use in nuclear power and 
research reactors. The recovery process produces both solid and liquid 
wastes (i.e., uranium byproduct material, or ``tailings''), which are 
transported from the extraction location to an on-site uranium 
byproduct material impoundment or pond.
---------------------------------------------------------------------------

    \6\ The term ``yellowcake'' is still commonly used to refer to 
this material, although in addition to yellow, the uranium oxide 
material can also be black or grey in color.
---------------------------------------------------------------------------

    Uranium byproduct materials/tailings deposited into an impoundment 
or ``mill tailings pile'' must be carefully monitored and controlled. 
This is because the mill tailings contain radioactive or heavy metal 
constituents, including thorium and radium. The radium decays to 
produce radon, which may then be released into the environment. Radon 
is a radioactive gas that may be inhaled into the respiratory tract; 
EPA has determined that exposure to radon and its daughter products 
contribute to an increased risk of lung cancer.\7\
---------------------------------------------------------------------------

    \7\ http://www.epa.gov/radon/risk_assessment.html.

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[[Page 4162]]

2. Heap Leaching
    Another method of uranium extraction that some facilities may use 
is known as heap leaching. This method has been used in situations 
where the uranium ore is of low grade or the geology of the ore body is 
such that conventional mining and milling is not cost effective. 
Although no such facilities currently operate in the United States, the 
heap leach process is used for uranium recovery in other parts of the 
world and has, to a limited extent, been used in the United States in 
the past. There are plans for at least one new heap leach facility to 
open in the U.S. within the next few years.
    With the heap leach process, small pieces of ore are placed in a 
large pile, or ``heap,'' on an impervious pad of plastic, clay, 
concrete, or asphalt, with perforated pipes under the heap. An acidic 
solution is then applied through drips or sprinklers over the ore to 
dissolve the uranium it contains. The uranium-rich solution drains into 
the perforated pipes, where it is collected and transferred to an ion 
exchange system to recover the uranium from the leaching solution. The 
heap is ``rested,'' meaning that there is a temporary cessation of 
application of acidic solution to allow for oxidation of the ore before 
leaching resumes. The ion exchange system extracts the uranium from the 
solution, which is processed into yellowcake either at the site or at 
another uranium recovery facility. The yellowcake is packed in special 
55-gallon drums to be transported to uranium conversion, enrichment and 
fuel fabrication facilities to produce fuel for use in nuclear power 
and research reactors.
3. In-Situ Recovery (ISR)
    In-situ recovery (ISR), also referred to as in-situ leach (ISL) (we 
will use the term ISR throughout this document), is now the dominant 
method of uranium recovery in the United States and much of the world. 
ISR research and development projects and associated pilot projects 
began in the 1960s in Wyoming with limited field applications. From the 
mid-1960s to the mid-1970s, interest in ISR methods increased, 
particularly in Texas and Wyoming, with 18 commercial and 9 pilot-scale 
operations in place by 1980. During the 1980s, production of uranium by 
ISR was limited, but by the mid-1990s, uranium production by ISR 
reached 90 percent of United States production. Commercial and pilot 
operations demonstrated ISR as a viable uranium recovery technique 
where site conditions (e.g., geology and hydrology) are amenable to its 
use. This technology can produce a better return on investment than 
conventional mining and milling since it does not involve excavation of 
large volumes of ore or disposal of large volumes of byproduct 
material. Therefore, the cost to produce uranium is generally lower. 
The trend in uranium production has shifted toward the ISR process. In 
2013, in the United States, there were six operating ISR facilities and 
12 facilities proposed for licensing, licensed but not operating, or 
undergoing restoration.
    In-situ recovery is defined as the underground recovery by 
oxidation/solubilization of uranium from the ore body (host rock--
typically sandstone) into the groundwater by using native groundwater 
into which oxidizing and complexing chemicals have been added. This 
solution is known as lixiviant. Lixiviant is pumped into the ore zone 
through a set of injection wells and removed through extraction wells, 
followed by recovery of uranium at the surface by processing of the 
extracted waters.
    The ore bodies most amenable to ISR are known as ``roll front'' 
deposits, which are formed when uranium in the oxidized groundwater 
encounters an area of the host formation where chemically reducing 
conditions exist. These reducing conditions are strong enough to 
chemically reduce and precipitate the uranium into a less soluble form, 
thus forming the ore zone. As new oxidized uranium enters the front, it 
continues to be chemically reduced, precipitate and deposit in 
successive ``rolls''. The injection of a lixiviant essentially reverses 
the geochemical reactions that originally formed the uranium deposit. 
The oxidizing agents in the lixiviant create an oxidizing environment 
that solubilizes the uranium from the formation and allows it to enter 
into the groundwater. Other components of the lixiviant (usually 
bicarbonate ions) act to enhance the solubility of the oxidized uranium 
in the groundwater. The uranium, along with other constituents present 
in the formation that have been mobilized (e.g., metals such as 
molybdenum, selenium, and arsenic), are then collected from the ore 
zone by extraction wells that pump the solution to the surface. At the 
surface, the uranium is collected by a system of piping that feeds to a 
processing facility, where the uranium is recovered in ion exchange 
columns and either further processed on-site into yellowcake, or 
transported to another facility for processing into yellowcake. After 
processing, the extracted and processed waters are recharged with the 
lixiviant chemicals and pumped back down into the ore zone for reuse in 
extracting more uranium. The yellowcake is subsequently transported to 
uranium conversion, enrichment, and fuel fabrication facilities to 
produce fuel for use in nuclear power and research reactors.
    Two general types of lixiviant solutions can be used, loosely 
defined as ``acidic'' or ``alkaline'' systems. Acidic lixiviants were 
used early in the development of ISR in the United States, but site-
specific conditions at the sites showed that acidic lixiviants were 
generally unsuitable.<SUP>8</SUP> <SUP>9</SUP> In the United States, 
the geology and geochemistry of the majority of the uranium ore bodies 
favors the use of alkaline lixiviants such as bicarbonate/carbonate and 
oxygen. Other factors in the choice of the lixiviant are the uranium 
recovery efficiencies, operating costs, and the ability to achieve 
satisfactory groundwater restoration after production ceases.
---------------------------------------------------------------------------

    \8\ Acidic lixiviants react with carbonates (calcite and 
dolomite) contained in the host rock and precipitate calcium 
sulfate. The calcium sulfate clogs the well screens and process 
lines, significantly decreasing the efficiency of the leaching 
process.
    \9\ Mudd, G.M. (2001). ``Critical review of acid in situ leach 
uranium mining: 1. USA and Australia,'' Environmental Geology, 
41:390-403.
---------------------------------------------------------------------------

    In order to control and contain the flow of groundwater within the 
production zone, an inward hydraulic gradient is established using the 
injection and extraction (also known as production) wells.\10\ To 
create and maintain this gradient, more water is removed from the 
production zone than is injected (commonly referred to by industry as 
the ``bleed rate''). The extracted liquid (groundwater mixed with 
lixiviant) goes through the recovery process to extract uranium. The 
processed water may be either recharged with lixiviant and re-injected 
to continue the recovery process or used to flush out the remaining 
lixiviant and mobilized uranium during the restoration process. Any 
waste water not reused may be injected into a deep well for disposal or 
be sent to an impoundment on site (often called an evaporation pond or 
a holding pond). The waste water generated during and after operations 
at an ISR facility, as well as all evaporation pond sludges derived 
from such waste waters, have been determined to be uranium byproduct 
material by the NRC, bringing

[[Page 4163]]

them under the jurisdiction of UMTRCA.\11\
---------------------------------------------------------------------------

    \10\ The gradient controls the direction of flow of water within 
a water-bearing formation. Used here, the purpose of a gradient is 
to contain water within the production zone so that it does not 
migrate beyond the wellfield.
    \11\ NRC (2000). ``Recommendations on Ways to Improve the 
Efficiency of NRC Regulations at In Situ Leach Uranium Recovery 
Facilities.'' Staff Requirements--SECY-99-013.
---------------------------------------------------------------------------

    The wellfield of an ISR operation is configured to efficiently 
exploit the underlying uranium ore zone based on the subsurface data 
collected prior to construction of the wellfield. The wellfield 
typically includes a series of closely spaced arrays of injection wells 
(each array typically has 4 to 6 injection wells spaced on the order of 
many tens to, at most, a few hundred feet apart) with an extraction 
well in the center of each array.\12\ Each of these arrays is intended 
to work as a unit to control the flow of groundwater bearing the 
lixiviant so that the injected solution is captured by the extraction 
wells. The spacing of the injection and extraction wells is determined 
by the hydrologic properties of the ore zone, as evidenced by 
hydrologic testing during the exploration of the site, wellfield 
construction and monitoring well construction and operation.
---------------------------------------------------------------------------

    \12\ See EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery (ISL/ISR) 
Sites.'' This document can be found in the docket for today's 
proposed rule. (Docket EPA-HQ-OAR-2012-0788).
---------------------------------------------------------------------------

    During operations there is a risk of the lixiviant and/or mobilized 
constituents spreading beyond the capture zone of the wellfield. This 
poses a risk of groundwater contamination off site and in some cases 
surface water contamination where groundwater discharges to surface 
water. Monitoring wells are positioned around the production zone to 
detect increases in indicator parameters that would signal an excursion 
of the lixiviant or mobilized constituents from an ISR wellfield into 
surrounding groundwater. The operator of the ISR facility typically 
remediates any detected excursions by taking corrective actions such as 
ceasing injection and pumping water out of wells near the excursion. 
The detection and remediation of excursions is a major regulatory 
operational concern and needs to be carefully monitored by the 
operators and the regulatory agencies.
    After the ore body has been depleted to uranium levels that are no 
longer economically valuable, the operator will cease injecting 
lixiviant and begin restoration of the ore zone aquifer within the 
wellfield(s) to return conditions to their preoperational state to the 
extent practicable. Extracted water, typically treated through reverse 
osmosis and often in combination with added reducing agents, is 
injected into the ore zone to flush out the remaining lixiviant and to 
attempt to restore the geochemistry of the ore zone to its original 
background (baseline) condition. Other procedures also may be used to 
bring about chemically reducing conditions in an attempt to immobilize 
the uranium (along with any other mobilized metals) remaining within 
the ore zone.
    Once the groundwater at the site has gone through restoration and 
sufficient time has passed such that the licensees can demonstrate that 
chemical conditions are stable, the injection and extraction wells are 
properly plugged and abandoned,\13\ the wellfield infrastructure 
(pipes, header houses, etc.) is removed, and surface operations 
equipment (impoundment liners, buildings, etc.) is dismantled and 
shipped offsite for appropriate reuse or disposal. The site is 
officially decommissioned when the radioactive materials license is 
terminated by the regulatory agency (i.e., NRC or NRC Agreement State). 
Because no long-term disposal facilities remain at decommissioned ISR 
sites, there is no perpetual care and monitoring as occurs with 
conventional mill tailings sites.
---------------------------------------------------------------------------

    \13\ See 40 CFR 146.10, ``Plugging and Abandoning Class I, II, 
III, IV, and V Wells.''
---------------------------------------------------------------------------

C. What is the statutory authority for the proposed amendments?

    EPA is proposing these new standards and amendments under its 
authority in Section 275 of the Atomic Energy Act (AEA) of 1954, as 
amended by Section 206 of the Uranium Mill Tailings Radiation Control 
Act (UMTRCA) of 1978.\14\
---------------------------------------------------------------------------

    \14\ See 42 U.S.C. 2022.
---------------------------------------------------------------------------

    Section 206 of UMTRCA authorizes EPA to promulgate general 
standards 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 at which ores are processed primarily for their 
uranium and thorium source material content \15\ or which are used for 
the disposal of such byproduct material (commonly known as Title II 
sites). See 42 U.S.C. 2022.\16\ These health, safety and environmental 
standards are contained in 40 CFR part 192 and are implemented by the 
NRC and its Agreement States, and the DOE.
---------------------------------------------------------------------------

    \15\ ``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.
    \16\ 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. EPA was 
directed to set general standards that were 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.
    Title II of the Act covers operating uranium processing or disposal 
sites licensed by the NRC or Agreement States. EPA was directed to 
promulgate generally applicable standards to protect public health, 
safety, and the environment from hazards associated with processing, 
possession, transfer and disposal of byproduct material. Such standards 
were to address both radiological and non-radiological hazards; 
further, standards applicable to non-radiological hazards were to be 
consistent with the standards required under Subtitle C of the Solid 
Waste Disposal Act (i.e., RCRA).\17\ NRC was required to implement 
these standards at Title II sites. See 42 U.S.C. 2022(b), (d).
---------------------------------------------------------------------------

    \17\ With the restriction that EPA not require any RCRA permit 
for the processing, possession, transfer, or disposal of byproduct 
material.
---------------------------------------------------------------------------

D. What are the existing requirements under 40 CFR part 192?

    Requirements for inactive uranium milling sites, vicinity 
properties, and depository sites (i.e., Title I sites) are addressed 
under subparts A, B and C of 40 CFR part 192. Since today's proposal 
does not impact Title I sites, they will not be discussed further in 
this section.
    Requirements currently applicable to active uranium processing and 
disposal sites, including ISR sites (i.e., Title II sites) can be found 
in subpart D of 40 CFR part 192 (hereafter ``subpart D''). Subpart D 
contains provisions for managing uranium byproduct materials during and 
following the processing of uranium ores, and restoration of disposal 
sites following any such use of those sites. For purposes of today's 
proposal, provisions related to groundwater protection are of most 
interest. To fulfill the statutory mandate described in section II.C of 
this preamble, we derived these provisions from the RCRA groundwater 
monitoring framework applicable to hazardous

[[Page 4164]]

waste disposal sites.\18\ Today's proposal further adapts that 
framework to better address the specific situation presented by ISR 
technology.
---------------------------------------------------------------------------

    \18\ See 40 CFR part 264, ``Standards for Owners and Operators 
of Hazardous Waste Treatment, Storage, and Disposal Facilities.'' 
See particularly subpart F, ``Releases from Solid Waste Management 
Units.''
---------------------------------------------------------------------------

    Though standards at subpart D apply to ISR facilities, ISR was not 
the predominant uranium extraction method at the time the standards 
were promulgated. Subpart D addresses contamination of aquifers 
resulting from releases of contaminants from uranium mill tailings 
impoundments, which are surface structures (engineered units) designed 
to contain uranium byproduct material (e.g., conventional tailings 
impoundments, evaporation or holding ponds). The RCRA hazardous waste 
framework, which is intended to prevent, detect, and mitigate 
contamination of groundwater resulting from releases of hazardous waste 
being held in an engineered unit, is directly applicable to this 
situation.\19\ A basic RCRA hazardous waste management unit is an 
engineered unit, designed, constructed, and installed to prevent any 
migration of wastes out of the unit to the adjacent subsurface soil, 
groundwater or surface water at any time during the unit's operating 
life, during closure and during post-closure.
---------------------------------------------------------------------------

    \19\ The design and construction requirements for surface 
impoundments are also taken from 40 CFR part 264. See subpart K, 
``Surface Impoundments,'' specifically 40 CFR 264.221.
---------------------------------------------------------------------------

    At ISR sites, however, the groundwater has already been influenced 
by the natural mineralization associated with the uranium roll front 
deposits. In essence, the ``management unit'' that is the potential 
source of contamination is the natural setting itself, though 
extraction of the uranium from the deposit alters the geochemistry of 
the ore-bearing formation and may increase the concentration of 
radionuclides and other metals in the water. Restoration activities 
attempt to restore the original geochemistry to the subsurface. 
However, at present, monitoring to verify restoration generally lasts 
for only a period of a few years at most. We are proposing to establish 
standards that will require licensees to ensure that the results of 
their restoration process(es) persist through time, thereby limiting 
the future potential for groundwater to be degraded from undetected, 
long-term changes in groundwater from ISR operations.

E. Why does EPA believe new standards are necessary?

    We believe that ISR-specific standards are necessary because 
uranium ISR operations are very different from conventional uranium 
mills and the existing standards do not adequately address their unique 
aspects.
    In particular, we believe it is necessary to take a longer view of 
groundwater protection than has been typical of current ISR industry 
practices. Although the presence of significant uranium deposits 
typically diminishes groundwater quality, current industry practices 
for restoration and monitoring of the affected aquifer may not be 
adequate to prevent either the further degradation of water quality or 
the more widespread contamination of groundwater that is suitable for 
human consumption.
    Because monitoring after restoration is typically conducted for 
only a short period, we find it difficult to characterize the 
probability or magnitude of future contamination problems, or the costs 
involved in remediating such future contamination. Such costs are not 
now borne by ISR licensees, nor is there any guarantee that they could 
be held responsible if contamination were detected by new monitoring 
implemented years, decades or even longer after the end of site 
activities once the facility is officially decommissioned and the 
license is terminated by the NRC or Agreement State. It is likely, 
however, that the costs of such future remediation would far exceed the 
costs of the more extensive monitoring (in all phases of site activity) 
that we are proposing today, together with the costs of any additional 
restoration or prompt corrective action that may be required to address 
any issues identified as a result of the more extensive monitoring. In 
this sense, perhaps a generalized future cost of groundwater 
remediation can be viewed as a proxy for the value of groundwater and 
its protection. Similarly, because ISR activities often take place in 
areas that are sparsely populated, and any subsequent contamination may 
take years, decades or even longer to reach groundwater being consumed 
by humans, it is difficult to characterize the benefits of our proposal 
by applying typical Agency metrics, such as the number of cancers 
averted.
    We also recognize, however, that our efforts to protect groundwater 
must consider the use, value, and vulnerability of the resource, as 
well as social and economic values. We believe it is important to 
protect groundwater to ensure the preservation of the nation's 
currently used and potential underground sources of drinking water 
(USDWs) for present and future generations. Also, we believe it is 
important to protect groundwater to ensure that where it interacts with 
surface water it does not interfere with the attainment of surface-
water-quality standards; these standards are also necessary to protect 
human health and the integrity of ecosystems.
    Thus, taking a more qualitative view of the situation leads us more 
broadly to consider the impacts on future groundwater uses. In many 
areas of the country, particularly in western states where ISR 
activities are most likely to take place, groundwater is a scarce and 
valuable resource that is being rapidly depleted to support increased 
demands. There is evidence that some communities are making efforts to 
utilize groundwater that is not of ``good'' quality, and in our view 
this trend will only increase.
    Another critical issue in groundwater protection is that 
groundwater generally is not directly accessible. Thus, it is much more 
difficult to monitor and/or decontaminate groundwater than is the case 
with other environmental media. Because of the expenses and 
difficulties associated with remediation of contaminated groundwater, 
we believe it is prudent and cost-effective to prevent the occurrence 
of such contamination rather than rely on the cleanup of preventable 
pollution.
    Thus, the Agency believes that it is in the national interest to 
preserve the quality of groundwater resources to the extent 
practicable, and that the best way to do so is to prevent contamination 
by addressing its source.\20\ We believe today's proposal, which 
focuses on the source of potential contamination at ISR sites by 
stricter application of groundwater standards and more extensive 
monitoring to ensure that groundwater restoration will endure, is a 
reasonable and responsible approach to achieving this goal.
---------------------------------------------------------------------------

    \20\ EPA (1991). ``Protecting the Nation's 
GroundwaterGroundwater: EPA's Strategy for the 1990s,'' 21Z-1020.
---------------------------------------------------------------------------

1. What are the environmental impacts of uranium ISR?
    As noted earlier, ISR facilities affect the environment in ways 
that are both distinct from, and more complicated than, conventional 
mill tailings sites. The alteration of large subsurface areas through 
injection of chemical solutions also has the potential to cause changes 
in groundwater at significant distances downgradient. The migration of 
constituents liberated from the

[[Page 4165]]

subsurface is controlled during the operational phase through the use 
of extraction wells.\21\
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    \21\ Extraction wells are also used during the restoration phase 
to control the migration of constituents liberated from the 
subsurface.
---------------------------------------------------------------------------

    Once uranium recovery operations at a wellfield are complete, 
efforts to restore groundwater in the wellfield begin. Without such 
efforts, contaminants could migrate hydrologically downgradient from 
the ISR site. Restoration efforts largely consist of injecting and 
extracting water to flush out the remaining mobilizing solutions (i.e., 
lixiviant) and chemical treatments designed to reverse the chemical 
process and return the prevailing chemical conditions (oxidizing) in 
the subsurface to their preoperational chemically reducing state.
    Much remains unknown about the geochemical stability of restored 
wellfields once ISR operations have ceased. Long-term environmental 
impacts may result if restoration processes do not return aquifers to 
their preoperational state, or if restored levels do not persist over 
time and groundwater degrades through the slow release of residual 
contaminants. Most ISR sites historically have been unable to meet 
restoration goals for all constituents even after extensive effort.\22\ 
Because the past practice of monitoring after restoration has typically 
been for a very limited time period, we do not know if the goals that 
are met for the short-term are maintained for a longer time.
---------------------------------------------------------------------------

    \22\ Hall, Susan (2009). ``Groundwater Restoration at Uranium 
In-Situ Recovery Mines, South Texas Coastal Plain.'' U.S. Geological 
Survey.
---------------------------------------------------------------------------

    The restoration process itself is extremely complex and difficult 
to control. The fact that significant quantities of uranium and other 
constituents have been removed from the natural setting may affect flow 
patterns and create discontinuities that further complicate or retard 
the restoration process. Originally, uranium was precipitated from 
groundwater moving through pore spaces in the host medium, which 
altered the flow paths on a local level throughout the deposit as the 
deposition of uranium continued and changed the porosity and 
permeability of the host medium. Once uranium extraction processes 
begin, fluids are pumped into the deposit to mobilize the precipitated 
uranium and remove it; the porosity and permeability of the host rock 
are also affected. Because the uranium is not initially distributed 
evenly throughout the deposit (because of the natural variations in the 
host rock properties), the extraction process cannot be assumed to 
remove all of the uranium; in fact, it does not. The restoration 
process likewise cannot be assumed to fully restore the porosity and 
permeability characteristics of the host rock to the exact conditions 
that existed before the ISR operations began. These changes in 
hydrologic properties in the host rock during extraction and 
restoration processes can have the net effect of altering flow paths 
within the deposit on a local level. Such largely unavoidable, 
incomplete restoration efforts may result in pockets of slowly leaching 
contaminants that may migrate out of the production zone over time.
    In the absence of explicit regulatory language addressing ISR 
facilities, NRC and its Agreement States have used guidance and license 
conditions to implement many aspects of groundwater protection 
programs, including the selection of restoration goals and post-
restoration monitoring. Based upon the information that we have 
reviewed,\23\ we believe an even more rigorous approach is warranted 
for (a) determining background groundwater concentrations, which are 
necessary to establish appropriate restoration goals, (b) establishing 
restoration goals, and (c) demonstrating the continued stability of 
groundwater after restoration. In addition, prolonged stability 
monitoring is needed to provide the necessary level of confidence that 
groundwater quality will not degrade over time or promote contaminant 
migration in the future.
---------------------------------------------------------------------------

    \23\ For example, Hall, Susan (2009). ``Groundwater Restoration 
at Uranium In-Situ Recovery Mines, South Texas Coastal Plain.'' U.S. 
Geological Survey.
---------------------------------------------------------------------------

    We recognize that it is difficult to reach a definitive conclusion 
regarding the frequency and extent to which long-term contamination has 
been or is likely to be a problem at ISR sites, because post-
restoration stability monitoring typically occurs for a relatively 
short timeframe, a few years at most; nevertheless, we believe the 
available information supports our concerns in this matter. Because the 
lixiviant used during operations oxidizes not just the uranium but the 
entire production zone, the effect from adding reducing agents to 
restore the wellfield may just be temporary. If these reducing agents 
migrate out of the production zone, re-oxidation of the uranium in the 
``restored'' wellfield may occur. This is especially likely if the 
natural reducing agents originally present in the production zone 
(i.e., organic materials and iron sulfide minerals) were sufficiently 
depleted during ISR operations. To determine if re-mobilization of 
constituents precipitated by the restoration process will occur, 
longer-term monitoring of the site is warranted.
    We are aware of the potential for geochemical conditions in the 
restored wellfield to alter over time. The ISR process can cause a loss 
of the chemically reducing potential in the ore zone. Over time, as 
oxidizing groundwater makes its way into the abandoned wellfield, re-
oxidation could occur. Given the slow groundwater travel times in these 
deposits, it would take even longer time for the degraded water to make 
its way to water supply wells downgradient of the production zone 
aquifer and be detected there. Therefore, when we speak of long-term 
alteration of the groundwater, we imply timeframes of decades (or 
longer) rather than a few years.
2. What analysis has EPA done to support the proposal?
    There is only very limited information in the open literature \24\ 
on the stability of a restored wellfield after ISR operations have 
ended. Typically, post-restoration monitoring concludes and license 
termination proceeds within a matter of several years after the 
restoration phase ends. The behavior of the restored wellfield in the 
long-term, i.e., decades or longer after the ISR operations end, has 
not been examined. The potential for re-mobilization of the 
contaminants is possible and this concern is the impetus for proposing 
longer post-restoration monitoring periods.
---------------------------------------------------------------------------

    \24\ Borch, T., N. Roche and T.E. Johnson (2012), 
``Determination of Contaminant Levels and Remediation Efficacy in 
Groundwater at a Former In Situ Recovery Uranium Mine.'' Journal of 
Environmental Monitoring, 14:1814-1823.
---------------------------------------------------------------------------

    We have assessed exposure scenarios and exposure pathways for 
potentially hazardous constituents (mainly radionuclides) and found 
that migration of contaminants within the ore-bearing aquifer and slow 
movement of contaminants into upper aquifers through discontinuities or 
disruptions (e.g., abandoned boreholes) and other possible failure 
scenarios (leaks, spills, etc.) have the potential to result in 
significant exposures to individuals outside the production areas.\25\ 
These assessments suggest that a robust regulatory approach is 
advisable in order to prevent various failure scenarios that may occur 
during and after ISR operations, and to mitigate the

[[Page 4166]]

potential adverse effects of any such failures.
---------------------------------------------------------------------------

    \25\ EPA (2012), ``Groundwater Modeling Studies at In Situ 
Leaching Facilities and Evaluation of Doses and Risks to Off-Site 
Receptors from Contaminated Groundwater.''
---------------------------------------------------------------------------

    In examining the technical literature pertaining to ISR operations, 
we have found that some modeling studies indicate that the uranium 
recovery operations can result in the development of relatively slower 
groundwater pathways through the wellfield, as well as the persistence 
of injected lixiviant within the production zone. These results suggest 
that the typically short post-remediation monitoring periods prior to 
license terminations may fail to detect subsequent contaminant 
migration out of the wellfield along these slow transport paths. We are 
proposing stability monitoring periods longer than the current practice 
and requirements to address these situations. Statistical analyses of 
well water chemistry data over a relatively short time (a year or two) 
alone does not in itself demonstrate that slow pathways are absent or 
that the groundwater will remain in a chemically reduced state over the 
long term. We believe that only a combination of longer stability 
monitoring and geochemical modeling using site-specific data can 
provide confidence that the ISR site poses no long-term hazards, and we 
are proposing such provisions today.
    We have also examined various statistical approaches that might be 
suitable for evaluating long-term groundwater stability.\26\ We gave 
special attention to the requirements for data to be used in deciding, 
with a given level of statistical confidence, that stability was 
achieved over a specified period of time. While we do not recommend any 
specific statistical method be applied universally to all ISR 
situations (because the hydrogeology and geochemistry of ISR sites are 
not uniform by nature and because there is more than one statistical 
method that can be used), we do believe that the method(s) chosen must 
be justified by the quality and quantity of the field data collected. 
Linear regression techniques are typically used to examine time series 
measurements (concentrations of groundwater constituents measured over 
time intervals) for the presence of trends in the data (i.e., to 
determine if the data show increases or decreases in the measured 
concentrations over time). While this type of analysis is relatively 
simple and can be used for quick screening to identify the presence of 
strong linear trends, it is often not sufficiently rigorous when used 
with field data because of significant limitations on the data sets. 
For linear regression assessments, the data must have a normal 
distribution and constant variance (two requirements that are difficult 
to demonstrate with field data). The data must have few or no values 
below the analytical detection limits for the measured parameter, and 
minimal outliers in the data or cyclical patterns (e.g., no detectable 
seasonality in the case of shallow aquifers). Field data rarely meet 
these conditions. Parametric and nonparametric techniques are more 
rigorous than simple linear regression but also have specific data 
demands. Parametric statistical tests require more complete data sets 
but require less data overall to reach the same statistical confidence 
levels as non-parametric tests, which are more tolerant of data 
shortcomings such as missing data in a series of measurements. Less 
than perfect data sets are common in field efforts, making non-
parametric techniques potentially more useful in practice. These 
methods are extensively assessed in the background information 
document.\27\ The EPA document, ``Statistical Analysis of Groundwater 
Monitoring Data at RCRA Facilities--Unified Guidance'' (2009), offers 
appropriate guidance on the level of confidence to be attained for 
demonstrating stability before regulatory decisions are made to 
terminate the operating license and release the wellfield for other 
uses. For RCRA monitoring results, where the intent is to ensure 
contaminants do not migrate out of the unit and into the uppermost 
aquifer, a confidence level of 95 percent is expected to support a 
regulatory action to terminate the permit.\28\ We believe an equivalent 
degree of confidence in the long-term stability of a restored ISR 
wellfield is appropriate.
---------------------------------------------------------------------------

    \26\ EPA (2014), ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
    \27\ Ibid.
    \28\ 40 CFR 264.97(h) & (i).
---------------------------------------------------------------------------

3. What came out of the Advisory from EPA's Science Advisory Board?
    In early 2011, we approached EPA's Science Advisory Board (SAB) 
\29\ to obtain advice regarding the complex scientific and technical 
issues related to groundwater protection at ISR sites. The SAB is an 
independent advisory body established by Congress in 1978 with a broad 
mandate to advise the Agency on technical matters. The SAB typically 
interacts with EPA programs through one of the following processes: (1) 
A consultation, which is a conceptual evaluation at the early stages of 
an action; (2) an advisory, which is typically a more detailed 
evaluation to address specific technical issues during development of a 
rule or technical guidance; or (3) a review, which is a detailed 
evaluation of a completed action to determine how the Agency 
incorporated science into its decision-making. The SAB will often 
conduct a review of an action on which it had previously weighed in 
through a consultation or advisory.
---------------------------------------------------------------------------

    \29\ http://yosemite.epa.gov/sab/sabpeople.nsf/WebCommittees/BOARD.
---------------------------------------------------------------------------

    We sought an advisory with the Radiation Advisory Committee (RAC), 
which is the committee of the SAB specializing in radiation issues. For 
purposes of this advisory, the RAC was augmented with several 
additional experts with specialized knowledge of geochemistry or 
hydrogeology pertinent to ISR.
    We prepared a report outlining the technical issues involved in 
groundwater protection during the life cycle of an ISR facility \30\ 
and requested that the RAC comment on the following:
---------------------------------------------------------------------------

    \30\ EPA 402/D-14-001 ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery (ISL/ISR) 
Sites,'' Environmental Protection Agency, 2014.
---------------------------------------------------------------------------

    (1) The technical areas described in the report and their relative 
importance for designing and implementing a groundwater monitoring 
network;
    (2) The proposed approaches for characterizing background 
(baseline) groundwater chemical conditions in the pre-operational phase 
and proposed approaches for determining the duration of such monitoring 
to establish background (baseline) conditions;
    (3) The approaches considered for monitoring in the long-term 
stability phase and the approaches considered for determining when 
groundwater chemistry has reached a ``stable'' level; and
    (4) Suitable statistical techniques that would be applicable for 
use with uranium ISR applications (particularly for the areas in items 
2 and 3 above), as well as the subsequent data requirements for their 
use.
    Public meetings/teleconferences of the advisory committee were held 
from July 12, 2011 through December 21, 2011, and included a two-day 
meeting in July 2011 with presentations by EPA management and staff, 
discussions with the RAC members, comments from members of the public, 
and initial reporting assignments for the RAC. NRC staff also attended 
the meetings and provided valuable input for the committee.
    The RAC submitted its final report on February 17, 2012.\31\ EPA 
responded to

[[Page 4167]]

each recommendation and updated its draft report as part of the 
technical background information document for this proposal.\32\ Among 
the more prominent RAC recommendations are the following:
---------------------------------------------------------------------------

    \31\ All information related to the advisory is located at 
http://yosemite.epa.gov/sab/sabproduct.nsf/c91996cd39a82f648525742400690127/0314cef928df63cc8525775200482fa3!OpenDocument.
    \32\ EPA (2014), ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
---------------------------------------------------------------------------

    <bullet> Identify indicators, both chemical and radioactive, for 
establishing conditions pre- and post-operationally, not limited to 
those with regulatory limits, but also including non-hazardous 
constituents that can affect the behavior of, or serve as surrogates 
for, constituents of interest;
    <bullet> Devote at least as much effort to defining background 
groundwater conditions as to post-operational trend monitoring;
    <bullet> Consider challenging and fluctuating ambient circumstances 
in background characterization;
    <bullet> Build in flexibility to modify the design and 
implementation of monitoring programs as new information becomes 
available;
    <bullet> Carefully qualify the meaning of ``return to 
preoperational groundwater quality'';
    <bullet> Match sampling frequency and duration to information needs 
for hydrogeologic model confirmation;
    <bullet> Present a survey of methods to determine sufficient well 
number and density; and
    <bullet> Select statistical evaluation approach in terms of 
strengths and weaknesses to suit questions to be answered.
    We believe today's proposal appropriately addresses these issues 
and incorporates the advice of the RAC.
4. What efforts has the Nuclear Regulatory Commission taken recently?
    NRC regulates uranium mills and mill tailings in accordance with 
Appendix A to 10 CFR part 40.\33\ Appendix A incorporates EPA's 40 CFR 
part 192 standards. NRC has developed guidance related to ISR 
activities \34\ and has implemented facility requirements through 
license conditions. Agreement States regulating ISR facilities have 
taken a similar approach.
---------------------------------------------------------------------------

    \33\ ``Criteria Relating to the Operation of Uranium Mills and 
the Disposition of Tailings or Wastes Produced by the Extraction or 
Concentration of Source Material From Ores Processed Primarily for 
Their Source Material Content.'' 10 CFR part 40 more broadly covers 
``Domestic Licensing of Source Material.''
    \34\ For example, see NRC (2003). ``Standard Review Plan for In 
Situ Leach Uranium Extraction License Applications (NUREG-1569).'' 
Available at http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1569/.
---------------------------------------------------------------------------

    In recent years, NRC has recognized the desirability of ISR-
specific regulations. NRC has been concerned with the potential for 
duplicative or conflicting groundwater protection requirements at ISR 
sites where NRC implements UMTRCA requirements but the EPA, or a state 
with primary enforcement responsibility (``primacy''), also regulates 
the injection associated with ISR through its Underground Injection 
Control (UIC) authorities, which are derived from EPA under the Safe 
Drinking Water Act (see Section II.F.1 of this document). In 2003, NRC 
staff recommended that NRC enter into a Memorandum of Understanding 
(MOU) with the affected states (at the time, Wyoming and Nebraska) to 
defer active regulation of groundwater to the states.\35\ This 
recommendation was approved by the Commission.
---------------------------------------------------------------------------

    \35\ NRC (2003). ``Options and Recommendations for NRC Deferring 
Active Regulation of Ground-Water Protection at In Situ Leach 
Uranium Extraction Facilities.'' SECY-03-0186.
---------------------------------------------------------------------------

    Upon further investigation, however, NRC staff reported to the 
Commission that ``the Nebraska and Wyoming groundwater protection 
programs were found to be not equivalent to the NRC's groundwater 
protection program.'' Specifically, both states required restoration of 
groundwater to ``a quality of use'' consistent ``with the uses for 
which [it] was suitable prior to'' the ISR operation, rather than to 
levels consistent with NRC and EPA restoration standards under 
UMTRCA.\36\
---------------------------------------------------------------------------

    \36\ NRC (2006). ``Status of the Development of Memoranda of 
Understanding with Nebraska and Wyoming, Regarding the Regulation of 
Groundwater Protection at Their In Situ Leach Uranium Recovery 
Facilities.'' SECY-05-0123.
---------------------------------------------------------------------------

    After considering this information, the Commission determined in 
2006 that the appropriate action was ``initiation of a rulemaking 
effort specifically tailored to groundwater protection programs at in 
situ leach (ISL) uranium recovery facilities.'' Further, the Commission 
directed that ``[t]he staff should focus on eliminating dual regulation 
by the NRC and EPA of groundwater protection. The NRC should retain its 
jurisdiction over the wellfield and groundwater under its Atomic Energy 
Act authority, but should defer active regulation of groundwater 
protection programs to the EPA or the EPA-authorized state through 
EPA's underground injection-control permit program.'' \37\
---------------------------------------------------------------------------

    \37\ NRC (2006). ``Regulation of Groundwater Protection at In 
Situ Leach Uranium Extraction Facilities.'' Staff Requirements--
COMJSM-06-0001.
---------------------------------------------------------------------------

    EPA disagreed with the approach recommended by the Commission. EPA 
has always held the position that UMTRCA is the controlling legal 
authority for protection of groundwater and NRC is obligated to 
implement the 40 CFR part 192 standards to carry out that function at 
ISR sites. Reliance on the requirements of the UIC program alone would 
not adequately address groundwater protection at ISR facilities, given 
that the purpose of the UIC program is to prevent endangerment of 
underground sources of drinking water (USDWs), not to address 
restoration of groundwater. Moreover, if the groundwater is not 
considered a USDW, as is typically the case at ISR sites, it is not 
protected under the Safe Drinking Water Act (SDWA). Reliance on the UIC 
program alone would also likely lead to inconsistent levels of 
protection since states can implement more stringent requirements than 
the national UIC requirements and, as NRC discovered, states with 
authority to implement the UIC program may not have groundwater 
protection requirements consistent with those that have been applied to 
conventional mills. EPA decided to address groundwater protection at 
ISR facilities by amending its UMTRCA standards, as we are proposing to 
do today. The Commission subsequently decided that the NRC rulemaking 
should be deferred until EPA's revised standards are final.\38\
---------------------------------------------------------------------------

    \38\ NRC (2011). ``NRC Regulatory Agenda: Semiannual Report, 
July-December 2010.'' NUREG-0936; Vol. 29, No. 2.
---------------------------------------------------------------------------

F. What other EPA statutes and regulations are relevant?

    There are several other EPA environmental statutes and regulations 
that are relevant to ISR facilities and operations. The Safe Drinking 
Water Act, Clean Water Act, Clean Air Act and Resource Conservation and 
Recovery Act are all detailed below. It should be noted that UMTRCA 
requires us to establish protections consistent with the requirements 
of the Resource Conservation and Recovery Act.
1. Safe Drinking Water Act (SDWA)
    The Safe Drinking Water Act (42 U.S.C. 300f et seq., 1974) is the 
main federal law that addresses drinking water. Under the SDWA, EPA 
sets health-based standards for drinking water to protect against 
naturally occurring and anthropogenic contaminants that may be found in 
drinking water.\39\ EPA and states work

[[Page 4168]]

together to implement those standards at public water systems.\40\ 
Implementing regulations in 40 CFR part 141 include the establishment 
of national primary drinking water standards.
---------------------------------------------------------------------------

    \39\ After reviewing health effects studies, EPA sets a Maximum 
Contaminant Level Goal (MCLG), the maximum level of a contaminant in 
drinking water at which no known or anticipated adverse effect on 
the health of persons would occur, and which allows an adequate 
margin of safety. MCLGs are non-enforceable public health goals. 
Since MCLGs consider only public health and not the limits of 
detection and treatment technology, sometimes they are set at a 
level which water systems cannot meet. When determining an MCLG, EPA 
considers the risk to sensitive subpopulations (infants, children, 
the elderly, and those with compromised immune systems) of 
experiencing a variety of adverse health effects. Once the MCLG is 
determined, EPA sets an enforceable standard. In most cases, the 
standard is a Maximum Contaminant Level (MCL), the maximum 
permissible level of a contaminant in water which is delivered to 
any user of a public water system. The MCL is set as close to the 
MCLG as feasible. EPA must determine the feasible MCL or treatment 
technique which the Safe Drinking Water Act defines as the level 
that may be achieved with the use of the best available technology, 
treatment techniques, and other means which EPA finds are available 
(after examination for efficiency under field conditions, not solely 
under laboratory conditions), taking cost into consideration.
    \40\ SDWA does not regulate private wells that serve fewer than 
25 individuals or have fewer than 15 service connections.
---------------------------------------------------------------------------

    The SDWA also addresses sources of drinking water, including 
underground sources, which may be used by public water systems or 
private well owners. As required by the SDWA, EPA established 
regulations for UIC programs to prevent underground injection that 
endangers drinking water sources.\41\ Under this program, the Agency 
has a permit system to prevent endangerment of USDWs. It prohibits any 
injection activity that allows the movement of fluid containing any 
contaminant into underground sources of drinking water if the presence 
of that contaminant may cause a violation of any primary drinking water 
regulation or otherwise adversely affect the health of persons. EPA's 
UIC regulations, including permit requirements, are found at 40 CFR 
parts 144-148. They address construction, operation, monitoring, 
reporting, and plugging and abandonment of injection wells to prevent 
the movement of fluids into any USDW.\42\
---------------------------------------------------------------------------

    \41\ SDWA Section 1421(c)(2)(C)(2) states: ``Underground 
injection endangers drinking water sources if such injection may 
result in the presence in underground water which supplies or can 
reasonably be expected to supply any public water system of any 
contaminant, and if the presence of such contaminant may result in 
such system's not complying with any national primary drinking water 
regulation or may otherwise adversely affect the health of 
persons.'' 42 U.S.C. 300h(d)(2).
    \42\ EPA defines six classes of underground injection well. 
Uranium in-situ recovery operations are permitted as Class III 
wells. 40 CFR 146.5(c)(2).
---------------------------------------------------------------------------

    EPA's UIC regulations for Class III wells protect USDWs by 
prohibiting the movement of any contaminant into the underground source 
of drinking water (e.g., injection of fluids or release or migration of 
naturally occurring contaminants into an underground source of drinking 
water). A USDW is defined in EPA regulations as any aquifer or its 
portion (a)(1) which supplies a public water system or (2) which 
contains a sufficient quantity of groundwater 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. The receiving aquifer 
must not meet the definition of a USDW. An aquifer or a portion of an 
aquifer may be exempted from the protections afforded USDWs 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,\43\ or 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.
---------------------------------------------------------------------------

    \43\ The presence of minerals or hydrocarbons that are, or are 
expected to be, commercially producible, is one of these specified 
conditions; this would likely be the situation at a proposed ISR 
site. 40 CFR 146.4.
---------------------------------------------------------------------------

    The construction of a Class III injection well at an ISR facility 
requires a UIC permit be obtained. Currently, ISR facilities are 
injecting lixiviant and extracting uranium from within exempted 
aquifers. If an underground injection well is used for injection into 
an exempted aquifer or a portion of an exempted aquifer, it is still 
regulated to protect the non-exempt portions of the USDW and other 
nearby USDWs. The scope of coverage of an aquifer exemption request is 
typically the portion of the USDW affected by the activity. It is 
possible that future ISR facilities will inject lixiviant and extract 
uranium from ore deposits that are within poorer quality aquifers that 
do not meet the definition of USDW; although an aquifer exemption would 
not be necessary in such a case, an UIC permit would still be required.
    EPA has established minimum requirements for states or tribes to 
obtain authority to implement the UIC program.\44\ To obtain 
``primacy'' to implement the UIC program for Class III wells, states or 
tribes must adopt and submit to EPA for approval, UIC Class III 
injection well requirements that are at least as stringent as EPA's 
minimum requirements. The state or tribe may establish and implement 
requirements more stringent than the EPA UIC regulations, but not less 
stringent than the minimum federal requirements. Further, primacy 
states have the authority to identify and propose aquifers for 
exemption as part of their initial UIC program submission, or 
subsequent to program approval; however, these proposed exemptions 
generally must be affirmatively approved by the EPA.\45\
---------------------------------------------------------------------------

    \44\ 40 CFR part 145, ``State UIC Program Requirements.''
    \45\ 40 CFR 144.7(b)(2) & (3).
---------------------------------------------------------------------------

    Aquifer exemptions have been a source of confusion regarding the 
applicability of our UMTRCA standards, which we hope to clarify today 
in this rule. There are limited UIC requirements relating to 
restoration of the exempted portion of the aquifer; \46\ furthermore, 
an aquifer exemption does not eliminate the need to comply with the 
requirements of UMTRCA. The aquifer exemption provides relief from 
certain UIC requirements under the SDWA, thereby allowing injection 
into aquifers that would otherwise meet the definition of a USDW. The 
part 192 standards, however, are promulgated under a different statute. 
Therefore, an aquifer exemption under the SDWA does not relieve the 
licensee of the obligation to remediate environmental contamination 
resulting from activities regulated under UMTRCA. Today's proposal 
clarifies that EPA standards issued pursuant to UMTRCA do apply within 
the exempted portion of the aquifer.
---------------------------------------------------------------------------

    \46\ 40 CFR 146.10(a)(4).
---------------------------------------------------------------------------

2. Clean Water Act (CWA)
    The Clean Water Act (33 U.S.C. 1251 et seq., 1972) requires the 
establishment of water quality standards for, and regulation of 
pollutant discharges into, waters of the United States. The CWA's 
definition of ``pollutant'' includes radioactive materials, 33 U.S.C. 
1362(6); EPA's regulations at 40 CFR 122.2 define the term 
``pollutant'' to include radioactive materials ``except those regulated 
under the Atomic Energy Act of 1954, as amended (42 U.S.C. 2011 et 
seq.) . . . .'' Radioactive materials covered by the AEA are those 
encompassed in its definitions of source, byproduct, and special 
nuclear materials. See 42 U.S.C. 2014. The radioactive materials EPA 
may regulate under the CWA ``are those not encompassed in the 
definition of source, byproduct or special nuclear materials as defined 
by the [AEA] and regulated pursuant to that Act.'' See Train v. 
Colorado Public Interest Research Group, Inc., 426 U.S. 1, 11 (1976). 
Under the CWA, EPA has implemented pollution control programs, such as

[[Page 4169]]

setting technology-based wastewater discharge limitations and standards 
for various industries. Subpart C of 40 CFR part 440 provides 
technology-based effluent limitations guidelines and standards 
applicable to discharges from mills at which uranium, radium and 
vanadium are extracted. Permits for discharges to surface waters must 
include applicable technology-based limits, as well as any more 
stringent water quality-based effluent limits necessary to achieve 
water quality standards established under Section 303 of the CWA, 
including state narrative criteria for water quality.
3. Clean Air Act (CAA)
    EPA regulates radionuclide emissions through its authority under 
the CAA, 42 U.S.C. 7401 et seq. The Agency has promulgated regulations 
for controlling radon emissions from operating uranium byproduct 
materials impoundments located at uranium recovery facilities, 
including ISR sites, at 40 CFR part 61, Subpart W.
4. Resource Conservation and Recovery Act (RCRA)
    The Resource Conservation and Recovery Act (42 U.S.C. 6901 et seq.) 
was passed in 1976 as an amendment to the Solid Waste Disposal Act of 
1965, to ensure that solid wastes are managed in an environmentally 
sound manner. RCRA gives EPA the authority to control hazardous waste 
from ``cradle-to-grave.'' This includes the generation, transportation, 
treatment, storage, and disposal of hazardous waste (Subtitle C). RCRA 
also set forth a framework for the management of non-hazardous solid 
wastes (Subtitle D). RCRA has been further amended to extend its 
application; for example, the 1986 amendments to RCRA enabled EPA to 
address environmental problems that could result from underground tanks 
storing petroleum and other hazardous substances.
    UMTRCA requires that generally applicable standards promulgated 
under its authority by EPA for non-radiological hazards be consistent 
with the standards issued under Subtitle C of the Solid Waste Disposal 
Act (now RCRA) that are applicable to those same hazards. The most 
appropriate RCRA regulations that bear on the ISR process are contained 
in 40 CFR part 264.\47\ These regulations deal with functionally 
relevant issues such as requirements for: The siting, design and 
operation of impoundments; monitoring groundwater around land-based 
storage and disposal facilities; detecting contaminant releases and 
conducting subsequent corrective actions; and establishing the duration 
of compliance monitoring periods. These requirements are easily applied 
to conventional mill tailings impoundments, which are to be constructed 
to RCRA standards, although they are expected to remain under 
institutional control for much longer periods.\48\ Similarly, we 
believe many of the requirements and concepts should be applicable to 
the long-term behavior of an ISR site after uranium extraction has 
ceased and the operators have made efforts to restore the wellfield to 
conditions that existed before the uranium recovery operation began. 
Conceptually, at that stage there is similarity between a closed 
hazardous waste disposal facility and a restored ISR wellfield in the 
sense that both strive to avoid off-site migration of contaminants. The 
intent of the groundwater monitoring efforts at these two types of 
facilities share the common objective of verifying that containment of 
contaminants meets expectations. The location of compliance point(s) 
for monitoring data collection, performance measures for assessing 
compliance with regulatory requirements, duration of the monitoring 
program and the extent of data necessary for regulatory decision-making 
are areas that we believe can be adapted to better fit the unique 
aspects of the ISR application. These subjects are discussed in the 
next section.
---------------------------------------------------------------------------

    \47\ ``Standards for Owners and Operators of Hazardous Waste 
Treatment, Storage, and Disposal Facilities.''
    \48\ These requirements also apply to any uranium byproduct 
impoundments (i.e., ponds) that are removed at the end of licensed 
operations.
---------------------------------------------------------------------------

III. Summary of Today's Proposal

    Today's proposal is limited to the following items. First, we are 
proposing new standards to explicitly address groundwater protection at 
uranium ISR facilities. Second, we are proposing to amend existing 
provisions only as necessary to address a judicial decision, an 
outdated reference and known typographical and grammatical errors. At 
this time, we request public comment only on these proposed standards 
and amendments. We are not requesting, and will not respond to, public 
comments related to any other provisions since they are beyond the 
scope of today's proposal. The rationale for these elements of our 
proposal is discussed in Section IV of this document.

A. Proposed Standards (Subpart F)

1. Proposal of a New Subpart--Subpart F--Public Health, Safety and 
Environmental Protection Standards for Byproduct Materials Produced by 
Uranium In-Situ Recovery
    A new subpart F is being proposed that would set standards that 
would apply to uranium ISR facilities only.
2. Addition of a New Section on Applicability--Sec.  192.50 
Applicability
    We are proposing applicability language under subpart F that 
specifies the subpart will apply to the management of uranium byproduct 
materials during and following the processing of uranium ores using ISR 
methods.
3. Addition of a New Section Containing Definitions--Sec.  192.51 
Definitions and Cross-References
    To help ensure consistency with subparts A, B, C, D and E, all 
terms in the proposed subpart shall carry the same meaning as 
previously defined, unless otherwise specified. To help ensure clarity, 
the new subpart will contain numerous definitions specific to ISR. The 
following terms are defined:

                               Terminology
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
Adjacent Aquifer
Alternate Concentration Limit (ACL)
Aquifer
Background
Constituent
Exceedance
Excursion
Excursion Monitoring Well
Exempted Aquifer
Extraction Well
Indicator Parameter
Injection Well
In-Situ Recovery (ISR)
Listed Constituent
Lixiviant
Long-Term Stability Phase
Maximum Constituent Concentration
Maximum Contaminant Level (MCL)
Monitoring Wells
Operational Phase
Overlying Aquifer
Point(s) of Compliance
Point(s) of Exposure
Preoperational Monitoring
Production Zone
Restoration (Act of)
Restoration Goal
Restoration Phase
Site
Stability Phase
Underlying Aquifer
Upper Control Limit (UCL)
Uranium Recovery Facility
Wellfield
------------------------------------------------------------------------


[[Page 4170]]

4. Addition of a New Section Detailing Standards--Sec.  192.52 
Standards
    In the new subpart, EPA proposes to specify the minimum 13 
constituents for which groundwater protection standards must be met. 
The list includes the following: Arsenic, barium, cadmium, chromium, 
lead, mercury, selenium, silver, nitrate (as N), molybdenum, combined 
radium-226 and radium-228, uranium (total), and gross alpha-particle 
activity (excluding radon and uranium). See section II.F.1 of the 
preamble and footnote for background. After groundwater restoration, 
the concentration of each listed constituent within the exempted 
aquifer of an ISR wellfield must remain at or below the most protective 
standards under the SDWA (40 CFR 141.61, 141.62, 141.66, 141.80 and 
143.3), values from RCRA standards (40 CFR 264.94), or Table 1 to 
subpart A of part 192, except in cases where the measured 
preoperational background concentration is higher than the most 
stringent value in the applicable regulations. In such cases, the 
measured background concentration will serve as the restoration goal. 
The proposed language allows for the regulatory agency to set 
groundwater protection standards for additional constituents as 
necessary, consistent with site conditions.
    The new subpart also describes the process for requesting and 
approving alternate concentration limits (ACLs) after restoration has 
taken place.
5. Addition of a New Section Discussing Monitoring Requirements--Sec.  
192.53 Monitoring Programs
    In addition to the constituents to be monitored at ISR facilities, 
the new subpart also details the specific requirements of monitoring 
programs to be conducted during the preoperational, operational, 
restoration, stability and long-term stability phases.
6. Addition of a New Section Establishing Requirements for Corrective 
Actions--Sec.  192.54 Corrective Action Program
    Should an excursion be detected or the proposed groundwater 
standards be exceeded at the excursion monitoring wells or long-term 
stability compliance wells at any licensed ISR site, we propose to 
require that a corrective action program be put into place as soon as 
is practicable and no later than 90 days after an excursion or an 
exceedance is discovered. Similar to the approach taken in subpart D, 
we propose that the corrective action program put into place meet the 
specifications of Sec.  264.100.
7. Addition of a New Section Detailing the Effective Date of the New 
Subpart--Sec.  192.55 Effective Date
    We are proposing that the rule go into effect 60 days after it is 
promulgated in the Federal Register, the legal minimum amount of time 
between promulgation of the new subpart and its effective date.\49\
---------------------------------------------------------------------------

    \49\ See 42 U.S.C. 2022(c)(3).
---------------------------------------------------------------------------

B. Other Proposed Amendments

1. Revision to Subpart C--Implementation
    In an effort to address an outdated reference, EPA proposes to 
remove mention of the Grand Junction Remedial Action Criteria (10 CFR 
712); the criteria were removed from the CFR between 1981 and 1982. In 
addition, EPA proposes to delete language citing certain remedial 
options that ``may provide reasonable assurance of'' radon decay 
product concentration reductions. The final report for the Grand 
Junction Remedial Action Program, issued in 1989, stated that the 
methods were not effective over the long term.
2. Revision to Subpart D--Standards for the Management of Uranium 
Byproduct Materials
    EPA proposes to amend the heading of Subpart D. The proposed 
amendment will remove an inaccurate citation of EPA's authority. In 
order to correct certain typographical and grammatical errors that have 
been identified in Subpart D since promulgation, EPA proposes the 
following technical corrections:

------------------------------------------------------------------------
                                       Proposed technical correction and
               Section                               reason
------------------------------------------------------------------------
Sec.   192.31(a).....................  Replace ``Uranium Mill Tailings
                                        Rediation Control Act'' with
                                        ``Uranium Mill Tailings
                                        Radiation Control Act'' to
                                        correct a typographical error.
Sec.   192.31(f).....................  Replace ``pile containing uranium
                                        by product materials'' with
                                        ``pile containing uranium
                                        byproduct materials'' to correct
                                        a typographical error.
Sec.   192.32(a)(2)(v)...............  Replace ``laser fusion, of soils,
                                        etc.'' with ``laser fusion of
                                        soils, etc.'' to correct a
                                        grammatical error.
------------------------------------------------------------------------

    EPA is also proposing to modify Sec.  192.32(a)(2)(v) in order to 
delete the NRC requirement to obtain concurrence from EPA before NRC 
may approve an alternate requirement or proposal under AEA section 
84(c).\50\ This portion of Sec.  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).
---------------------------------------------------------------------------

    \50\ See 42 U.S.C. 2114(c).
---------------------------------------------------------------------------

IV. What is the Rationale for today's proposal?

    Groundwater is one of our nation's most precious resources. A 
significant portion of the U.S. population draws on groundwater for its 
potable water supply. In addition to serving as a source of drinking 
water, people use groundwater for irrigation, stock watering, food 
preparation, personal health and hygiene, and various industrial 
processes. When that water is radioactively contaminated, each of those 
uses becomes a radiation exposure pathway for people. Groundwater 
contamination is also of concern to us because of potential adverse 
impacts upon ecosystems, particularly sensitive or endangered 
ecosystems. For these reasons, it is a resource that needs protection.
    A number of federal and state laws have been passed through the 
years to protect drinking water. At the federal level, the SDWA 
(discussed in detail in Section II.F.1) establishes the basic framework 
for protecting the drinking water used by public water systems in the 
United States. This law contains requirements for ensuring the safety 
of the nation's public drinking water supplies. At the state level, 
many similar drinking water and water use laws have been passed.
    Groundwater is also a valuable and dwindling resource, particularly 
in western states where most ISR activities are anticipated. EPA views 
protecting groundwater as a fundamental part of its mission. 
Particularly in cases where groundwater is directly threatened by an 
activity, as it is by the ISR technology, EPA believes it has a special 
duty to ensure that the authority of all applicable federal statutes 
(e.g.,

[[Page 4171]]

UMTRCA and the SDWA) are used to help protect the groundwater and that 
appropriate standards to protect public health, safety and the 
environment are developed and implemented.
    We anticipate the objection that the presence of uranium deposits 
typically results in groundwater of poor quality, and not a pristine 
source of drinking water. We recognize that this is often the case, and 
that the volume of water affected by the mineralized zone may be 
significant. We do not, however, see this as a reason to allow this 
groundwater to be further degraded. The increasing scarcity of 
groundwater is leading some communities to consider using sources of 
water that previously would have been considered non-potable, using 
advanced treatment to make it suitable for livestock or human 
consumption. Since such advanced treatment may not be economically 
feasible for some communities, it is all the more important to prevent, 
as much as reasonably possible, additional degradation of the 
groundwater.
    A guiding philosophy in radioactive waste management, as well as 
waste disposal in general, has been to avoid imposing burdens on future 
generations for clean-up efforts as a result of management approaches 
that are reasonably anticipated to result in pollution in the future. 
Adhering to the concept of sustainability, we should not knowingly 
impose undue burdens on future generations. Imposing performance 
requirements that avoid polluting resources that reasonably could be 
used in the future, therefore, is a more appropriate choice than 
imposing clean-up burdens on future generations. ISR facilities use 
significant volumes of water during both operations and restoration. We 
believe it is reasonable to make every effort to ensure that ISR 
activities leave groundwater in no worse condition than pre-ISR 
operational status.

A. How does today's proposal relate to existing 40 CFR part 192?

    In 1983, EPA promulgated regulations at 40 CFR part 192 in response 
to the statutory requirements of UMTRCA. At the time, uranium recovery 
from ore was done almost exclusively by conventional milling processes, 
where at most a few pounds of uranium were recovered for each ton of 
ore mined and processed. The wastes from the milling process (the 
tailings and raffinates, i.e., uranium byproduct materials) were 
disposed of in large piles on the surface at mill sites, posing 
contamination risks to surface water, groundwater, and soils, both on 
and off site. Liquid wastes were often discharged into rivers. 
Contaminants of concern consisted primarily of radionuclides and non-
radioactive metals, radon gas and organics. Concerns that these 
tailings piles would be a continuing source of radiation exposure and 
environmental contamination unless properly reclaimed and managed were 
the driving force behind the passage of UMTRCA. The statute's intent 
was to contain tailings in engineered impoundments to prevent the 
further dispersion and misuse of the material. This measure would also 
protect uncontaminated aquifers from becoming contaminated by the 
uranium mill tailings impoundments and prevent radon emissions through 
performance specifications for radon barriers (covers). Because the 
major environmental risk at that time was perceived to come from the 
conventional uranium mill tailings, which already existed in large 
volumes, other uranium recovery technologies, including ISR, received 
little attention.
    As stated earlier, ISR has surpassed conventional milling as the 
dominant form of uranium extraction in the United States and is 
expected to predominate in the future. The ISR process presents 
different environmental concerns from conventional milling. ISR does 
not generate large volumes of solid waste materials or require 
permanent tailings impoundments. The ISR process does, however, 
directly alter groundwater chemistry, posing the challenge of 
groundwater restoration and long-term subsurface geochemical 
stabilization after the ISR operational phase ends. With ISR, the 
``milling'' of uranium ore is performed within the ore zone aquifer by 
injection of lixiviants. As stated earlier, the lixiviants can also 
liberate other elements, particularly metals that are often found co-
located with uranium deposits. Their migration outside the production 
zone can potentially contaminate surrounding aquifers. Furthermore, 
when processing of the ore zone is no longer economically viable, ISR 
operators can release the site for future use, either by selling the 
land or returning the property to the original owner. The operators are 
required to restore the aquifer to its original geochemical conditions, 
to the extent possible, and to show some level of stability in the 
geochemistry of the production zone before terminating the license and 
making the site available for other uses. Whereas conventional mill 
tailings piles are under perpetual institutional control, current NRC 
regulations allow for ISR sites to terminate their licenses, 
essentially ending regulatory oversight of the site.
    Today, EPA is reaffirming that ISR facilities are subject to the 40 
CFR part 192 requirements. We seek to provide clear direction on how to 
monitor groundwater in and around the production zone during all phases 
of the ISR facility's lifecycle, and how to demonstrate geochemical 
stability at these sites.
    We believe there has been some uncertainty about how to apply the 
current standards, which are more targeted to conventional mills, to 
ISR sites. In addition, there has been confusion about applicability of 
UMTRCA restoration requirements at aquifers that have been exempted 
from the standards of the SDWA. With the prospect of additional ISR 
facilities beginning operations, we believe it is necessary to clarify 
these issues. Therefore, we are proposing additional groundwater 
protection provisions to 40 CFR part 192 that are specific to uranium 
ISR facilities and consistent with the SDWA and RCRA. We believe these 
provisions are necessary to ensure that ISR sites are not released from 
regulatory control until it can be reasonably demonstrated that 
groundwater will not degrade over time.
    Specifically, we are proposing provisions that will result in long 
lasting protection of surrounding aquifers. The provisions specify how 
to determine preoperational background conditions that will be used to 
set appropriate restoration goals, applicable standards and alternate 
concentration limits. We are also proposing specifications for long-
term groundwater stability monitoring and a corrective action program 
that is triggered if excursions/exceedances do occur. We view these as 
the key elements in ensuring that ISR sites do not become a source of 
continuing or widespread contamination after the ISR operation is 
terminated.
    Sufficient data must be collected to characterize the conditions 
existing within and outside the proposed production zone to set 
appropriate groundwater protection standards (i.e., restoration goals) 
that account for the variability in geochemistry frequently encountered 
in mineralized regions. Subsequent to the end of uranium production, 
the regulator must ensure that alternate standards are approved only 
after restoration has been attempted and it is clearly demonstrated 
that the initial groundwater protection standard(s) cannot be achieved, 
or once achieved, cannot be maintained. Such approval should take place 
only after the operator has made reasonable and

[[Page 4172]]

satisfactory efforts to achieve and maintain the initial standard(s) 
and fully considered a number of factors. Whether the initial goals are 
met or alternate concentration limits are approved, conditions must be 
shown to be stable and groundwater quality must not degrade over time, 
as is possible when: lingering amounts of lixiviant solution remain in 
isolated pockets within the wellfield; reducing conditions are not 
fully reestablished; and/or the long-term stability monitoring period 
is too short compared to the time it takes for groundwater to move 
through the aquifer. Therefore, the operator must monitor groundwater 
at the site for a sufficiently long period after restoration is 
complete and use statistically significant results to provide a 
reasonable demonstration that long-term stability has been achieved. 
This demonstration can include geochemical modeling to confirm the 
persistence of stability of the groundwater chemistry. Geochemical 
modeling can provide a defensible demonstration of an aquifer's natural 
capacity to maintain stability, which statistics alone cannot provide. 
Although the selection and application of geochemical models will be on 
a site-specific basis, geochemical models that have been used to 
predict the fate and transport of uranium at ISR facilities include 
PHT3D, PHREEQC, and PHAST.
    We intend for today's proposal to eliminate any confusion about the 
relationship of the aquifer exemption process to restoration 
requirements at ISR sites. We further recognize that the application of 
the existing standards in 40 CFR part 192 to ISR sites is not as 
straightforward as it could be. Nevertheless, we believe there is 
sufficient information available to indicate that practices related to 
groundwater protection at ISR facilities have not been sufficiently 
rigorous to provide confidence either that groundwater is being 
restored appropriately or that such restoration will persist into the 
reasonably foreseeable future.<SUP>51 52 53</SUP> We believe today's 
proposal addresses these issues in a manner that is both logical and 
implementable;\54\ we solicit comment on our view of the current 
situation and the overall approach of our proposal.
---------------------------------------------------------------------------

    \51\ Hall, Susan (2009). ``Groundwater Restoration at Uranium 
In-Situ Recovery Mines, South Texas Coastal Plain.'' U.S. Geological 
Survey.
    \52\ Darling, Bruce (2008). ``Report on Findings Related to the 
Restoration of Groundwater at In-Situ Uranium Mines in South 
Texas.'' Southwest Groundwater Consulting, LLC.
    \53\ Fettus, G. and M.G. McKinzie (2012). ``Nuclear Fuel's Dirty 
Beginnings: Environmental Damage and Public Health Risks from 
Uranium Mining in the American West.'' Natural Resources Defense 
Council.
    \54\ It should be noted that we are not proposing to establish 
specific requirements related to the technical aspects of 
groundwater restoration (i.e., what methods to use for restoration 
or which statistical methods to use for assessing temporal stability 
of the groundwater chemical state).
---------------------------------------------------------------------------

B. What groundwater protection standards are we proposing for ISR 
facilities?

    We are proposing today to establish groundwater protection 
standards consistent with those applied to conventional mills in 40 CFR 
part 192, subpart D. That is, the licensee will use as the applicable 
standard during restoration and long-term stability monitoring either 
(1) the background concentrations of groundwater constituents measured 
prior to the start of the ISR operational phase; or (2) a specified 
regulatory level, whichever is higher. In certain circumstances, the 
licensee may request that the regulatory agency approve an alternate 
concentration limit.
1. Generally Applicable Groundwater Standards
    We emphasize again that the groundwater protection standards 
currently found in 40 CFR part 192 apply to ISR sites. These standards 
address both radiological and non-radiological constituents. The 
standards applicable to non-radiological constituents adopted the 
requirements for groundwater monitoring at RCRA hazardous waste 
sites.\55\ These generally applicable standards were originally based 
upon EPA's 1976 Maximum Contaminant Levels (MCLs) in drinking water (40 
CFR part 141).\56\ See section II.F.1 of the preamble and footnote for 
background. EPA further specified radiological and non-radiological 
constituents of concern at mill tailings sites. Following the same 
approach, we are proposing today to specify, as Table 1 to subpart F, 
the constituents that must be monitored at ISR sites, as appropriate. 
The required constituents mirror those included in Table 1 to subpart A 
of 40 CFR part 192, with the exception of the six pesticides.\57\
---------------------------------------------------------------------------

    \55\ 40 CFR 264.94, Table 1.
    \56\ 47 FR 32285, July 26, 1982. The use of MCLs as standards 
for groundwater protection anticipated the Agency's Ground Water 
Protection Strategy, first developed in 1984 and updated in 1991. 
Under the Strategy, MCLs provide a benchmark for groundwater 
protection. Contamination of groundwater above MCLs is viewed as a 
failure of pollution prevention.
    \57\ Endrin, lindane, methoxychlor, toxaphene, 2,4-D, and 2,4,5-
TP Silvex. These constituents are unlikely to be present at ISR 
sites.
---------------------------------------------------------------------------

    We are not proposing to establish new numerical standards in the 
rule. EPA's preferred option for carrying over and updating the 
groundwater protection standards in the new ISR-specific subpart F is 
to incorporate, by reference, the most protective standards issued 
under the SDWA (40 CFR 141.61, 141.62, 141.66, 141.80 and 143.3), 
values from RCRA standards (40 CFR 264.94), and the maximum constituent 
concentrations found in Table 1 to subpart A of 40 CFR part 192. By 
incorporating these standards by reference, the new subpart F would 
automatically update if those concentration values change in the 
standards under SDWA or RCRA and thereby, be self-implementing. Upon 
promulgation, licensees currently in restoration, stability monitoring 
or long-term monitoring at a given wellfield at a licensed facility 
would continue to be held to the standard(s) in place at the time of 
licensing for those given wellfield(s), unless the regulatory agency 
determines otherwise. Operating wellfields, new wellfields and 
expansions of wellfields would be required to meet the newly 
promulgated standards. This option would make the groundwater 
protection standards under the proposed subpart consistent with all 
relevant current and future standards under SDWA and RCRA. We believe 
that this approach will more effectively keep the groundwater 
protection standards current with the Agency's policies while providing 
for regulatory certainty. The standards in the existing portion of 40 
CFR part 192 are outdated for arsenic and uranium, both of which have 
had new MCLs established since the year 2000.\58\ Today's proposal 
would update the standards for arsenic and uranium as they apply to ISR 
facilities. Should the Agency propose to update its MCLs or RCRA 
standards at some point in the future, stakeholders will have the 
opportunity to comment on the potential impacts to ISR activities.
---------------------------------------------------------------------------

    \58\ 66 FR 6976, January 22, 2001; and 65 FR 76708, December 7, 
2000, respectively.
---------------------------------------------------------------------------

    We are also considering the alternative approach of placing a 
static table of restoration goals in the new subpart F. The table would 
list the 13 required constituents for which groundwater protection 
standards must be met, and also provide the specific numeric 
concentration value associated with each constituent. If this option is 
promulgated in the final rule, the standards would not automatically 
update with any future changes to standards under the SDWA or RCRA but 
would remain static. Under this

[[Page 4173]]

approach, the Agency would initiate future changes to standards through 
a notice-and-comment rulemaking specifically for 40 CFR part 192.
    In order for an ISR operation to proceed, a UIC permit is required 
and typically, an aquifer exemption is needed as well. The exemption 
effectively removes from the protection of the SDWA, an aquifer or 
portion of an aquifer that would otherwise meet the definition of an 
underground source of drinking water. The wellfield used by the ISR 
operation to extract the uranium deposit may constitute only a portion 
of the overall exempted area. As noted in Section II.E.1 of this 
document, there is no similar exemption for the aquifer from the 
requirements of UMTRCA, nor does UMTRCA contemplate such a concept. We 
emphasize again that the SDWA-based aquifer exemption does not relieve 
the operator of an ISR facility of the obligation to remediate 
environmental contamination resulting from activities regulated under 
UMTRCA, both within and outside the exempted portion of the aquifer.
2. Alternate Concentration Limits (ACLS)
    Consistent with RCRA, EPA currently allows the use of ACLs if the 
operator is unable to restore groundwater to either preoperational 
background conditions/concentration levels or the applicable 
restoration goals. Today we propose to clarify the requirements for 
requesting and granting ACLs in the production zone, after restoration 
efforts have taken place. While the 19 criteria to be considered in 
granting ACLs are spelled out for Title II sites in 40 CFR 
192.32(a)(2)(iv) through incorporation of 40 CFR 264.94(b), they have 
not always been implemented as intended.<SUP>59 60</SUP> In the past, 
NRC and Agreement States have issued secondary class-of-use restoration 
goals at ISR sites, but these goals were typically less restrictive 
than meeting background concentration levels.\61\ NRC no longer 
recognizes class-of-use as an appropriate standard for restoration of 
groundwater at uranium ISR facilities; \62\ secondary class-of-use 
restoration goals are inconsistent with the requirements of 40 CFR part 
192 and 10 CFR part 40, Appendix A. There is evidence that relaxed 
restoration standards have been granted in Agreement States,\63\ and 
some instances where ACLs have been identified and approved by the 
regulator before restoration efforts have been initiated and/or 
completed.<SUP>64 65</SUP> We believe these situations can result in 
insufficient protection of groundwater; in particular, we believe it 
only is appropriate to establish restoration goals based on a thorough 
characterization of the preoperational environment and not to approve 
ACLs unless it has proven impracticable to achieve or maintain the 
initial restoration goals or return to background conditions after 
restoration. With this proposal, we specify the conditions that must be 
met prior to requesting an ACL and emphasize the factors that must be 
considered in establishing and approving ACLs. These factors specify 
that, if ACLs are deemed necessary or appropriate after all best 
practicable restoration activities have been completed, they must not 
pose a substantial present or potential hazard to human health or the 
environment.\66\ ACLs can be established for carcinogens and/or non-
carcinogens. When considering the potential for health risks caused by 
human exposure to known or suspected carcinogens, ACLs should, where 
practicable, be established at concentration levels that represent a 
cumulative excess lifetime risk to an average individual at no greater 
than 10<SUP>-4</SUP> (one chance in ten thousand).
---------------------------------------------------------------------------

    \59\ These criteria are also reproduced for Title I sites in 40 
CFR 192.02(c)(3)(ii).
    \60\ EPA (1987). ``Alternate Concentration Limit Guidance, 
Interim Final,'' provides guidance to RCRA facility permit 
applicants and writers concerning the establishment of RCRA 
Alternate Concentration Limits. The guidance lists 19 factors, or 
criteria, that are used to evaluate ACL requests.
    \61\ ``Class of use'' designates the potential uses of 
groundwater based on its quality. For example, groundwater that is 
not suitable for human consumption may be designated for livestock. 
Class of use typically encompasses a range of constituent 
concentration values.
    \62\ NRC (2009). ``Uranium Recovery Policy Regarding: (1) The 
process for scheduling licensing reviews of applications for new 
uranium recovery facilities and (2) the restoration of groundwater 
at licensed uranium in situ recovery facilities.'' NRC Regulatory 
Issue Summary 2009-05.
    \63\ Darling, Bruce (2008). ``Report on Findings Related to the 
Restoration of Groundwater at In-Situ Uranium Mines in South 
Texas.'' Southwest Groundwater Consulting, LLC.
    \64\ Hall, Susan (2009). ``Groundwater Restoration at Uranium 
In-Situ Recovery Mines, South Texas Coastal Plain.'' U.S. Geological 
Survey.
    \65\ Fettus, G. and M.G. McKinzie (2012). ``Nuclear Fuel's Dirty 
Beginnings: Environmental Damage and Public Health Risks from 
Uranium Mining in the American West.'' Natural Resources Defense 
Council.
    \66\ ``[A] licensee may propose alternatives to specific 
requirements adopted and enforced by the Commission under this 
chapter. Such alternative proposals may take into account local or 
regional conditions, including geology, topography, hydrology and 
meteorology. The Commission may treat such alternatives as 
satisfying Commission requirements if the Commission determines that 
such alternatives will achieve a level of stabilization and 
containment of the sites concerned, and a level of protection for 
public health, safety, and the environment from radiological and 
nonradiological hazards associated with such sites, which is 
equivalent to, to the extent practicable, or more stringent than the 
level which would be achieved by standards and requirements adopted 
and enforced by the Commission for the same purpose and any final 
standards promulgated by the Administrator of the Environmental 
Protection Agency in accordance with section 2022 of this title.'' 
42 U.S.C. 2114(c), emphasis added.
---------------------------------------------------------------------------

    The regulatory agency may face situations in which the operator 
will request ACLs. If after extensive effort the operator determines 
that the initial restoration goals for one or more constituents cannot 
be achieved as required in the license, the operator may request and 
the regulatory agency may approve the levels that have been achieved as 
provisional ACLs and determine that restoration is complete (i.e., that 
there is no statistically significant trend in the concentrations of 
regulated species over time). Then, the operator may request and the 
regulatory agency may approve final ACLs if post-restoration monitoring 
indicates three consecutive years of stability at the 95 percent 
confidence level. The approval of final ACLs, however, would not by 
itself satisfy the requirements for long-term stability monitoring.
    In the second case, after restoration is complete, the operator may 
find that post-restoration monitoring detects increases in the 
concentration of one or more constituents of concern. Depending on the 
statistical significance of the increase, the regulatory agency may 
determine that further attempts at restoration or corrective action are 
needed. If the situation persists after such action is taken, the 
regulatory agency may choose to wait and see if the increase levels off 
(i.e., stabilizes). If stabilization does occur, the operator may 
request and the regulatory agency may approve final ACLs if post-
restoration monitoring indicates three consecutive years of stability 
at the 95 percent confidence level.
    An additional consideration is the potential effect of ACLs on 
groundwater downgradient of the wellfield. The granting of ACLs could 
be viewed as inconsistent with the purpose of groundwater restoration, 
which is to prevent contamination of groundwater resources beyond the 
production zone. However, NRC has in recent years adopted an approach 
defining the ``point of exposure'' as the aquifer exemption boundary, 
where the initial restoration goal must be met. We propose to adopt a 
similar approach today.\67\ This will ensure that the non-

[[Page 4174]]

endangerment condition of the UIC permit will be sustained. We believe 
the decision to grant an ACL is among the most important that the 
regulatory agency can make. We believe our proposal appropriately 
clarifies the situations in which ACLs can be considered and emphasizes 
the factors that must be considered, thereby making the overall process 
more rigorous. However, we also recognize that the regulatory agency 
may need to spend additional effort to evaluate the full record of 
activities at the site in order to determine whether an ACL is 
appropriate, and at what level. Because the long-term protectiveness of 
this decision may not be fully understood until well after site 
activities conclude and the license is terminated, we encourage the 
regulatory agency to inform and seek input from the affected public 
when ACLs are being considered. We believe this request would 
constitute a license amendment significant enough to warrant an 
opportunity for public comment, if not public hearings.
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    \67\ EPA guidance on application of ACLs under RCRA makes a 
similar distinction between the ``point of compliance'' and the 
``point of exposure,'' emphasizing that in granting ACLs, (1) 
groundwater plumes should not increase in size or concentration 
above allowable health or environmental exposure levels; (2) 
increased property holdings should not be used to allow a greater 
ACL; and (3) ACLs should not be established so as to contaminate 
off-site groundwater above allowable health or environmental 
exposure levels. See http://www.epa.gov/wastes/hazard/correctiveaction/resources/guidance/gw/acl.htm.
---------------------------------------------------------------------------

C. Adequate Characterization of Groundwater Prior to Uranium Recovery

    To design and operate an ISR facility, the chemical composition and 
hydrology of the groundwater in and around the ore body must first be 
rigorously characterized. Defining the configuration of the ore zone 
and designing the production zone for uranium recovery requires 
detailed subsurface information obtained from geophysical 
investigations, including but not limited to logs and cores.\68\ In 
addition, the groundwater in the production zone is also characterized 
to determine the proposed chemical composition of the lixiviant and to 
determine background groundwater chemistry by which to set restoration 
goals for the post-production phase of the ISR operation (i.e., the 
efforts to return the groundwater chemical conditions in the production 
zone to those that existed prior to the uranium recovery efforts). The 
preoperational chemical composition of the groundwater in the 
production zone is called ``baseline'' in practice within the ISR 
industry and by NRC. In EPA documents and regulations the term 
``background'' is used to indicate the original state of groundwater 
before activities take place that may introduce contamination into the 
groundwater, such as leakage of contaminants from a surface or near-
surface waste disposal cell or an underground source of contamination 
such as leaking storage tanks or disposal wells.\69\
---------------------------------------------------------------------------

    \68\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
    \69\ For example, owners and operators of hazardous waste 
facilities are required to have a monitoring system that can 
``represent the quality of background water that has not been 
affected by leakage from a regulated unit.'' 40 CFR 264.97(a)(1).
---------------------------------------------------------------------------

    For the ISR method, there are a number of ``backgrounds'' involved, 
the most important being the preoperational background within the 
portion of the ore zone where uranium production will take place (i.e., 
the production zone). Knowledge of this background is necessary to 
design the leaching process and set restoration goals--two very 
important steps in the ISR operation. ``Background'' groundwater 
composition data are also needed in portions of the aquifer surrounding 
the wellfield and in overlying and underlying aquifers that may have 
communication with the uranium ore-bearing aquifer to determine whether 
excursions occur during operations, and to determine whether seasonal 
variations in groundwater chemistry are occurring in shallow aquifers. 
Background data are also needed for geochemical modeling of the 
groundwater in the production zone and downgradient to support 
assessments of the natural capacity of the restored production area and 
downgradient portion of the exempted aquifer to maintain long-term 
stability of the restored wellfield.
    There are spatial and temporal designations for the various 
``backgrounds'' measured in relation to an ISR operation. For instance, 
preoperational background is determined above, below, around and within 
the wellfield in the exempted aquifer. The preoperational background 
downgradient of the wellfield and in aquifers above and below the 
production zone are needed to detect any excursions that may occur 
during the ISR operational phase or restoration phase. The uses of the 
various ``backgrounds'' are described in the technical background 
information document supporting this rulemaking.\70\
---------------------------------------------------------------------------

    \70\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
---------------------------------------------------------------------------

    NRC requires establishment of background at uranium recovery sites 
in its regulations at 10 CFR part 40, Appendix A, Criterion 7; \71\ 
most of the implementing requirements are found in guidance and license 
conditions. Today's proposal includes provisions to ensure that 
operators adequately characterize preoperational conditions inside and 
outside the wellfield. This characterization is necessary to establish 
appropriately protective restoration goals that are representative of 
the wellfield, accounting for natural variability. There is evidence 
that regulators and operators have at times used high-end values to 
represent the overall wellfield or have used a generalized ``class-of-
use'' for the groundwater to set restoration goals.\72\ We do not 
believe this is appropriate, as we explain below.
---------------------------------------------------------------------------

    \71\ ``At least one full year prior to any major site 
construction, a preoperational monitoring program must be conducted 
to provide complete baseline data on a milling site and its 
environs. Throughout the construction and operating phases of the 
mill, an operational monitoring program must be conducted to measure 
or evaluate compliance with applicable standards and regulations; to 
evaluate performance of control systems and procedures; to evaluate 
environmental impacts of operation; and to detect potential long-
term effects.''
    \72\ 12. NRC (2006). ``Status of the Development of Memoranda of 
Understanding with Nebraska and Wyoming, Regarding the Regulation of 
Groundwater Protection at Their In Situ Leach Uranium Recovery 
Facilities.'' SECY-05-0123.
---------------------------------------------------------------------------

    Today's proposal also specifies that the preoperational groundwater 
monitoring program must account for the effects of well installation 
and development on the groundwater characteristics. The physical act of 
penetrating the aquifer to install the well can cause localized changes 
in constituent concentrations or chemical parameters, which can lead to 
a misleading picture of background conditions. This can, in turn, 
result in selection of artificially high restoration goals. It is 
important that the operator allow a sufficient interval of time between 
well installation and sampling to allow localized disturbances to 
dissipate and ensure that background conditions are accurately 
characterized.
1. Establishing Restoration Goals
    The successful protection of groundwater at ISR sites begins with 
the selection of rigorous and appropriate restoration goals. As 
described in Section III.B of this preamble, restoration goals will be 
established as the preoperational background concentration or as a 
specified regulatory level for that constituent, whichever is higher.
    This is more complicated than it might seem. ISR wellfields may 
cover areas of 10 acres or more, and the presence of mineralized zones 
often means that there is significant variability within the proposed 
production area. As a result, background

[[Page 4175]]

concentrations in one area of the wellfield may diverge significantly 
from those measured elsewhere. The question, then, is whether it is 
possible to select a single level that is representative of the entire 
wellfield and, if not, how measurements should be evaluated.
    We stated previously that we do not believe it is appropriate to 
select among high-end measurements as representative values for 
restoration. It might be argued, however, that restoring a given well 
to its preoperational values would be an indication that restoration 
would be equally successful in the rest of the wellfield. This might be 
the case at sites where remediation of groundwater is focused on 
removing a contaminant that has been introduced from outside the 
system; however, we question the general application of this assumption 
at ISR sites. As discussed earlier, the initial deposition 
(precipitation) of uranium mineralization is uneven and alters the 
porosity and permeability of the host rock. The extraction and 
restoration processes at ISR sites are imperfect and further alter the 
distribution of the uranium in the deposit. Flow paths and velocities 
in local areas are altered as a result of changes in porosity and 
permeability that occur from the removal of material from pore spaces 
and later re-precipitation. It is possible that areas of heavy and 
lighter mineralization or groundwater concentrations can change from 
the distribution existing before uranium recovery to that after 
restoration, reflecting the degree to which the oxidizing and reducing 
agents contact the mineralization. As a result of these changes, ``hot 
spots'' may be found at wells that initially registered lower 
constituent concentration measurements, and vice versa.
    Because of the site-specific nature of this variability, we are 
proposing today that operators utilize background measurements from 
across the wellfield, combined with appropriate statistical techniques, 
to determine restoration goals. As appropriate, goals may be developed 
for individual wells, groups of wells, or the entire wellfield. The 
point(s) of compliance for restoration will be determined by the 
operator and regulatory agency after a thorough technical evaluation of 
the operator's geophysical investigation.

D. Excursions

    During the operational and restoration phases at an ISR wellfield, 
it is possible that lixiviant or byproduct fluids can escape the 
capture zones of the extraction wells and move toward the monitoring 
well ring surrounding the production zone. The placement of the 
injection and extraction wells, combined with their relative pumping 
rates, are designed to prevent such movement,\73\ but heterogeneities 
in the aquifer characteristics and difficulties in maintaining perfect 
performance of the wellfield can lead to lateral excursions as well as 
excursions into overlying and underlying aquifers (i.e., vertical 
excursions). Detecting these excursions is a prime focus of regulatory 
attention. Indicators of excursions (e.g., increases in concentrations 
of certain indicator parameters, such as, but not limited to, chloride 
ion concentrations above the preoperational background) are typically 
defined in the license conditions, as are requirements for reporting 
excursions to the regulatory authorities and corrective action 
requirements once an excursion is detected. The excursion monitoring 
wells are positioned far enough away from the injection and extraction 
wells so as to not be affected by the production processes, but close 
enough to detect excursions in a timely manner. The spacing of wells 
within the monitoring ring must prevent contaminants from passing 
between the wells. The excursion monitoring wells should also be far 
enough from the aquifer exemption boundary to ensure that any necessary 
corrective action can be taken before a USDW is adversely impacted. We 
have seen instances where the outer monitoring ring is essentially 
coincident with the boundary of the exempted aquifer. We do not believe 
this practice is appropriate. While it may allow the operator to limit 
the amount of land dedicated to the ISR facility, it provides little 
margin for error in preventing contaminants from reaching protected 
aquifers (i.e., USDWs), and may hamper corrective actions should they 
be needed.
---------------------------------------------------------------------------

    \73\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
---------------------------------------------------------------------------

    Today we are proposing to adopt a definition of ``excursion'' 
consistent with that used by NRC in license conditions. Under this 
definition, an excursion is identified when two or more indicator 
parameters are measured at levels exceeding their upper control limits 
(essentially, background levels) at perimeter monitoring wells or in 
monitoring wells in overlying or underlying aquifers. Thus, an 
excursion can take place vertically between aquifers as well as 
horizontally within the aquifer from which uranium is being extracted.
    This approach differs somewhat from that taken under RCRA to detect 
releases of hazardous constituents, so it is important that we 
distinguish between the two approaches and explain why our proposed 
approach is more suitable in the ISR context and consistent with law.
    Monitoring under RCRA is conducted to detect any evidence that an 
engineered hazardous waste unit (e.g., a landfill or impoundment) has 
failed. To that end, the detection monitoring program includes not only 
indicator parameters that might signal a change in groundwater 
chemistry or quality, but also hazardous constituents contained in the 
waste unit.\74\ The statistically significant detection of any 
monitored parameter or constituent triggers further investigation and 
potentially corrective action. Because the engineered unit has been 
introduced into the environment and the monitoring takes place at the 
edge of the unit, it is unlikely that a detection can be attributed to 
the natural variability in the groundwater at the site. Detection of a 
single parameter or constituent appropriately triggers action in this 
case because, in addition to remediating groundwater, the failure of 
the unit itself must be addressed to prevent further releases.
---------------------------------------------------------------------------

    \74\ See 40 CFR 264.98.
---------------------------------------------------------------------------

    By contrast, at an ISR site all constituents that may be 
``released'' are part of the natural setting, and their presence in 
groundwater may vary over time. Only the lixiviant is introduced from 
outside the natural system. Therefore, the ``indicator parameters'' are 
typically those that most reflect the lixiviant properties. For 
example, chloride is often incorporated into the lixiviant as a tracer; 
similarly, because the lixiviant mobilizes uranium by increasing 
alkalinity, a significant increase in alkalinity at excursion 
monitoring wells may signal that lixiviant has escaped the production 
zone extraction wells. Because the lixiviant typically moves more 
rapidly than the mineral constituents, increases in the properties 
associated with the lixiviant will most likely be detected well before 
the other constituents reach the excursion monitoring wells. The 
presence of these parameters in the natural groundwater accounts for 
the reliance on detecting two such parameters at levels above their 
upper control limits to signal an excursion, rather than only one.
    We believe this approach to defining excursions (i.e., relying on 
two indicator parameters) is reasonable and has been shown to be 
workable in practice. We are also proposing to define ``upper

[[Page 4176]]

control limit'' consistent with NRC's use of the term. The ``upper 
control limit'' defines the level of an indicator parameter that, when 
two of which are detected at excursion monitoring wells, would signal 
an excursion; as described above, indicator parameters will typically 
be identified in the facility license.
    It is important that the upper control limits be set appropriately 
to account for both background levels of indicator parameters and the 
characteristics of the lixiviant. We agree with NRC that ``upper 
control limit concentrations of the chosen excursion indicators should 
be set high enough that false positives (false alarms from natural 
fluctuations in water chemistry) are not a frequent problem, but not so 
high that significant groundwater quality degradation could occur by 
the time an excursion is identified.'' \75\ We have heard some concerns 
that upper control limits have in some cases been established at levels 
that would be unlikely to be exceeded under any conditions, thereby 
eliminating the possibility of detecting an excursion altogether. Such 
a situation must be avoided.
---------------------------------------------------------------------------

    \75\ See NRC (2003). ``Standard Review Plan for In Situ Leach 
Uranium Extraction License Applications.'' NUREG-1569, page 5-40.
---------------------------------------------------------------------------

    Upper control limits can be calculated using various statistical 
techniques, but are often derived by adding a multiple of the standard 
deviation to the mean of a distribution. EPA's Unified Guidance \76\ 
covers methods that can be used to develop control limits or prediction 
limits, which serve a similar function. NRC staff describes its current 
view of acceptable practice in NUREG-1569 \77\: ``The staff has decided 
that in areas with good water quality (total dissolved solids less than 
500 mg/l), setting the upper control limit at a value of 5 standard 
deviations above the mean of the measured [background] concentrations 
is an acceptable approach.'' \78\
---------------------------------------------------------------------------

    \76\ EPA (2009). ``Statistical Analysis of Groundwater 
Monitoring Data at RCRA Facilities--Unified Guidance.''
    \77\ NRC (2003). ``Standard Review Plan for In Situ Leach 
Uranium Extraction License Applications.'' NUREG-1569.
    \78\ Ibid, page 5-41.
---------------------------------------------------------------------------

    The potential for excursions may also be a factor in the facility's 
decision to stop operations and enter the restoration phase. In some 
cases, conventional mills may enter a standby period, in which they 
stop processing ore with the intent to resume operations at some point 
in the future (the price of uranium is often the decisive factor in 
these decisions). In some cases, mills have remained on standby for 
years at a time. For an ISR facility, however, such a ``standby'' 
period is inappropriate because the migration of constituents mobilized 
by the prior injection of lixiviant continues even if the decision is 
made to stop extracting uranium. Excursions beyond the production zone 
are more likely to occur if the gradient within the wellfield is not 
maintained. In our view, stopping the extraction cycle must be 
interpreted as an end to the operational phase and should trigger 
initiation of the restoration phase. We are interested in stakeholder 
views on this interpretation.

E. Long-Term Stability Monitoring

    Perhaps the most significant aspect of today's proposal involves 
the actions to be taken by the operator after groundwater restoration 
is complete. If insufficient monitoring is conducted, either in 
duration, frequency, or in the number of wells used to sample the 
wellfield, it is very possible to reach premature conclusions of 
stability. In such cases, residual lixiviant or localized areas within 
the production zone that have not stabilized may cause continued 
mobilization of uranium and other constituents after monitoring is 
terminated, potentially leading to contamination downgradient or beyond 
the boundary of the exempted aquifer. Today's proposal contains 
provisions related both to the duration of the monitoring and to the 
sufficiency of the data necessary to determine that stability has been 
achieved.
    After the ISR operational phase ends, the altered chemical state 
has to be returned to the preoperational conditions, to the extent 
possible, so that uranium and other contaminants do not migrate outside 
the wellfield. Treatments to re-establish chemically reducing 
conditions (which greatly reduce the uranium concentration in the ore 
zone groundwater) can restore groundwater constituents to 
preoperational background levels to a large extent, although experience 
has shown that restoration of all constituents to the preoperational 
background level is seldom 100 percent successful.\79\ In addition, the 
chemically reducing conditions initially present, and the mechanisms 
that maintained these conditions originally, may not be restored 
sufficiently to persist over the long-term. Re-oxidation of treated 
groundwater-host rock systems in other situations has been observed, 
and post-restoration monitoring at ISR locations has historically been 
relatively short, typically six months to periods of no more than a few 
years. A slow re-oxidation process with the resulting potential for 
enhanced migration of uranium and other contaminants may not be 
detected during a relatively short post-restoration monitoring period. 
Such an event could occur if the oxidizing agents in the lixiviant 
significantly removed the reducing agents originally present in the ore 
zone (e.g., organic material and iron sulfide minerals) that were 
responsible for sequestering the uranium to form the ore deposit in the 
first place. Over time, naturally oxygenated waters entering the ore 
zone from up gradient could re-oxidize the uranium removed from 
solution during the restoration process, mobilizing it once again and 
transporting it downgradient beyond the wellfield. To determine whether 
a trend of increased concentrations is occurring, it is necessary to 
monitor over long periods of time and use statistical techniques to 
analyze the data. This is particularly important if the trend in 
increased concentrations is relatively slow and the natural variability 
in the well samples is relatively high. These difficulties point to the 
need for longer post-restoration monitoring periods than historically 
performed. However, as discussed earlier, the choice of appropriate 
statistical techniques to determine the presence or absence of trends 
in monitoring data can be complicated by shortcomings in the monitoring 
database, such as missing measurements, ``nondetects,'' analytical 
errors and other causes that are difficult to avoid in practice for 
long timeframe monitoring efforts.\80\ We have considered several 
options for the length of the long-term stability monitoring period as 
described below.
---------------------------------------------------------------------------

    \79\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
    \80\ Ibid.
---------------------------------------------------------------------------

1. Thirty-Year Long-Term Stability Monitoring Period, With Provisions 
for Shortening That Time Period
    The initial part of our proposal for long-term stability monitoring 
addresses the duration of monitoring. Specifically, we are proposing 
that a facility must demonstrate three consecutive years of stability 
monitoring and then maintain long-term stability monitoring for an 
additional period of 30 years; this timeframe can be shortened by 
demonstrating long-term geochemical stability through modeling, as 
described below. In determining the appropriate length of long-term 
stability monitoring to provide confidence that the restored wellfield 
conditions will remain stable over time, and considering our statutory 
direction for consistency with RCRA

[[Page 4177]]

requirements, we find that some direction can indeed be found in the 
RCRA regulatory framework. For RCRA hazardous waste disposal 
facilities, a post-closure monitoring period of thirty years is 
required before permit termination can occur.\81\ Since an engineered 
RCRA disposal facility for the containment of chemically hazardous 
waste is similar in concept to relying upon a chemically treated ISR 
wellfield to contain the potential spread of contaminants, we believe 
it is reasonable to conclude that a thirty-year long-term stability 
monitoring period for ISR activities is a consistent application of 
RCRA requirements. We have examined various statistical techniques for 
determining the presence or absence of trends in monitoring data, under 
assumed levels of natural variability and extent of trending, and 
concluded that, under reasonable values for these variables, a thirty-
year monitoring period is a reasonable length of time to detect upward 
trends in constituent concentrations.\82\
---------------------------------------------------------------------------

    \81\ See 40 CFR 264.117(a)(1).
    \82\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
---------------------------------------------------------------------------

    We recognize that a thirty-year monitoring period would be 
significantly longer than current practice and that stability may be 
achieved in a shorter timeframe. Therefore, we are also proposing a 
provision that would allow the regulatory agency to shorten the 
monitoring period \83\ if the operator can both demonstrate geochemical 
stability through monitoring and support a conclusion of long-term 
stability through geochemical modeling. We believe that modeling, which 
can provide confidence that a geochemical environment exists to prevent 
uranium and other constituents from re-mobilizing, is an important 
element of any decision to shorten the monitoring period. Further, we 
believe this provision will encourage operators to expend more effort 
in preoperational site characterization, which will improve their 
modeling efforts.\84\
---------------------------------------------------------------------------

    \83\ This decision authority is also present in RCRA 
regulations: ``. . . any time during the post-closure period for a 
particular unit, the Regional Administrator may . . . shorten the 
post-closure care period applicable to the hazardous waste 
management unit. . . if he finds that the reduced period is 
sufficient to protect human health and the environment . . .'' 40 
CFR 264.117(a)(2).
    \84\ The Agency recently took a similar approach in defining the 
post-injection monitoring timeframe applicable to Class VI wells 
used for carbon dioxide geologic sequestration. Owners or operators 
of Class VI injection wells are required to monitor for at least 50 
years after the cessation of injection, unless an alternative 
timeframe is approved. Further, the monitoring period can be 
shortened if it can be demonstrated, based on monitoring and other 
site-specific data, that the project no longer poses an endangerment 
to USDWs. See 40 CFR 146.93(b).
---------------------------------------------------------------------------

    We are proposing that three consecutive years of stability be 
demonstrated through monitoring as a prerequisite before the modeling 
would be considered as justification for reducing the monitoring 
period. The three-year stability demonstration begins when sufficient 
monitoring data have been collected to allow a showing of statistical 
significance at a specified level of confidence. This three-year 
demonstration period has its roots in the RCRA framework, where it is a 
metric for the success of corrective action after groundwater 
contamination has been detected.\85\ We also see this situation as 
analogous to the restoration of the ISR wellfield. Stability would be 
demonstrated statistically at the 95 percent confidence level, which we 
believe will help to ensure that operators collect data of sufficient 
quantity to support regulatory judgments. Stability would be 
demonstrated using statistical tests with sufficient power to detect 
trends with a false negative rate no higher than 5 percent. We believe 
this will ensure that operators collect data of sufficient quantity and 
quality with adequate power to support regulatory judgments. As noted 
in Section II.E.2 of this document, a 95 percent confidence threshold 
can also be found in the RCRA monitoring program.
---------------------------------------------------------------------------

    \85\ ``If the owner or operator is engaged in a corrective 
action program at the end of the compliance period specified in 
paragraph (a) of this section, the compliance period is extended 
until the owner or operator can demonstrate that the ground-water 
protection standard of Sec.  264.92 has not been exceeded for a 
period of three consecutive years.'' 40 CFR 26.96(c). ``The owner or 
operator may terminate corrective action measures taken beyond the 
period equal to the active life of the waste management area 
(including the closure period) if he can demonstrate, based on data 
from the ground-water monitoring program under paragraph (d) of this 
section, that the ground-water protection standard of Sec.  264.92 
has not been exceeded for three consecutive years.'' 40 CFR 
264.100(f).
---------------------------------------------------------------------------

2. What Other Options Did EPA Consider For the Long-Term Stability 
Monitoring Period?
    In addition to the option described above, EPA considered two 
alternatives related to the duration of long-term stability monitoring. 
We are interested in receiving comments and data on all three options 
described.
a. Required Thirty-Year Long-Term Stability Monitoring Period
    The second option we considered also relies on the RCRA regulatory 
framework. In this alternative, no provision for shortening the long-
term stability monitoring time frame is permitted; thirty years of 
groundwater monitoring is required. This alternative provides a 
significant increase in the monitoring period over current industry 
practice, and the extended time would provide added confidence that the 
restored wellfield chemistry is remaining stable through this period of 
time. Thirty years of consistent statistical performance (i.e., no 
upward trending) would provide strong support for concluding that 
groundwater systems will remain in a chemically reduced state over 
time. If upward trending of contaminant concentrations was observed 
during the monitoring period under this approach, the operator would be 
required to perform additional corrective action, after which the 
monitoring period would begin again. We ultimately decided not to 
pursue this option because it does not sufficiently recognize the site-
specific aspects of aquifer restoration or give operators the incentive 
to reach license termination sooner by conducting geochemical modeling.
b. Narrative Standard With No Fixed Monitoring Period
    We also considered the option of a performance-based standard 
without explicitly calling for a long-term monitoring period. We 
considered requiring that two conditions be met (i.e., return of the 
physical hydrologic system to a condition similar to the preoperational 
flow regime and stability of the geochemical environment) before 
license termination. To meet the first condition, return of the 
physical hydrologic system, no significant residual influences from the 
injection-extraction restoration cycle could remain after restoration. 
This would include conditions such as hydraulic head and flow 
direction. Depending on the site, this would likely take many months 
and perhaps a year or more. To meet the second condition, stability of 
the geochemical environment, the operator would have to show that the 
groundwater chemistry is statistically stable at a 95 percent 
confidence level for a duration of time sufficient to account for site 
conditions. These site conditions would include such things as 
variability of constituents in the wellfield, groundwater velocity, 
constituent travel times and any seasonal influences. We expect it to 
take at least several years to collect data sufficient to achieve the 
95 percent confidence level. With this approach, the regulatory agency 
would have maximum flexibility in determining whether to establish 
general

[[Page 4178]]

requirements or approach each site on an individual basis.
    Ultimately, we decided against this approach for several reasons. 
Statistical analyses alone, without the added requirement of long-term 
monitoring or the option of geochemical modeling, would provide no 
assurance that groundwater systems will remain in a chemically reduced 
state over a longer time frame than that used for data collection. 
Furthermore, this option does not incorporate RCRA's thirty-year post-
closure period. As previously stated, UMTRCA requires that generally 
applicable standards promulgated under its authority by EPA for non-
radiological hazards be consistent with the standards issued under 
Subtitle C of RCRA. Based on these two reasons, we feel that this 
approach has greater potential for premature termination of the 
license. Furthermore, ambiguity in the narrative nature of such 
standards has the potential to provoke litigation and make 
implementation difficult.
3. How will groundwater stability be determined?
    The success of a groundwater restoration effort will be measured 
ultimately not only by whether the restoration goals are achieved, but 
also by whether those levels can persist and the geochemistry of the 
groundwater remain stable in the long term. The primary intent of the 
restoration effort is to return the chemical condition of the 
groundwater in the production zone to the state that existed prior to 
the initiation of the ISR operations; restoring the hydrologic regime 
is also important. The persistence in time (i.e., stability) of the 
chemical condition developed during restoration is the ultimate measure 
of success for the aquifer restoration effort. We define stability as 
the state in which the concentrations of the constituents in the 
groundwater remain relatively constant over time, with no significant 
upward trending. The key factor in determining stability, then, is 
developing a meaningful measure by which to determine whether trending 
is occurring. Such a measure must address the sufficiency of the data 
collected, both over time and in its spatial distribution within the 
wellfield. We discussed the proposed monitoring timeframes in the 
previous section. The remainder of this section describes how we 
propose to determine whether groundwater chemistry is stable and where 
we propose to apply this method.
a. What do we propose for determining stability?
    There are some similarities between a hazardous waste land disposal 
situation and an ISR operation that allow us to draw on the RCRA 
experience for developing standards. Both the RCRA disposal technology 
and the post-operation aquifer restoration efforts for an ISR operation 
are intended to prevent contaminants from migrating in the environment. 
However, there are some differences that apply to developing ISR 
standards. An ISR production zone differs from a hazardous waste 
disposal situation in that the contaminants of potential concern 
(largely uranium and radium) were present at significant levels 
entrained within the host rock of the aquifer before ISR operations 
began and will still be present, to some extent, in the groundwater 
after the aquifer restoration effort has ended; the process will not 
completely remove them. The concentrations of contaminants of potential 
concern are subject to natural temporal variations both before and 
after ISR operations, and this variability must be taken into 
consideration in setting standards for judging the adequacy of aquifer 
restoration. Because of this natural variability, repeated sampling of 
the post-restoration groundwater must be done to judge the adequacy of 
the restoration process. To assess when the chemical condition in the 
wellfield groundwater has become stable, statistical measures and 
analyses are necessary for examining temporal variations in the water 
composition data collected over a period of time. Today we are 
proposing to establish a statistical level of confidence as the 
standard for determining stability of post-restoration groundwater. We 
believe this is a relatively simple and straightforward way to 
represent the level of rigor we believe is necessary to conclude that 
concentrations of important constituents in the groundwater are not 
increasing significantly over time.
    Determining when groundwater compositions have achieved temporal 
stability will be a site-specific decision, dependent on the natural 
variability at the site, which is in turn dependent on many site-
specific factors (e.g., spatial variations in uranium mineral 
distribution within the aquifer, variations in other chemical 
constituents that affect uranium dissolution), the frequency of sample 
collection, and the magnitude of any trends in composition that may be 
present relative to the magnitude of natural variability. Chapter 7 of 
the technical background information document supporting this 
rulemaking discusses these aspects of stability monitoring in much 
greater detail and illustrates the relationships between sampling 
frequency and data trends with time.\86\ Because of the site-specific 
interplay between the variables that affect stability, we are not 
proposing to specify what statistical methods the operator should use 
to make this determination. There are a variety of methods available 
that could prove appropriate given the specific conditions at each 
site. These would include both parametric and non-parametric methods. 
We recommend that readers consult EPA's ``Statistical Analysis of 
Groundwater Monitoring Data at RCRA Facilities--Unified Guidance'' 
(2009), which provides exhaustive discussion of methods that have been 
considered for use in the RCRA program. Further discussion of 
statistical methods for determining trends in groundwater data may also 
be found in EPA's technical background information document, which was 
prepared to support this proposal.\87\ We emphasize that the choice of 
statistical method must be based on the quantity and quality of the 
available data and must be justified accordingly to the implementing 
regulatory agency.
---------------------------------------------------------------------------

    \86\ EPA (2014). ``Considerations Related to Post Closure 
Monitoring of Uranium In-Situ Leach/In-Situ Recovery Sites.''
    \87\ Ibid.
---------------------------------------------------------------------------

    The intent of the statistical analysis of groundwater monitoring 
data is to avoid a situation where a wellfield that is unstable is 
judged to have reached temporal and spatial stability. An appropriate 
statistical analysis will help to ensure that the regulatory decision 
reflects a high degree of confidence in the interpretation of the 
monitoring data. We are proposing that a statistical confidence level 
of upper 95 percent confidence limit be used to determine stability 
over time. This level of confidence is often used in regulatory 
applications, including in the RCRA groundwater monitoring 
framework.\88\ We believe that an equivalent level of confidence, and 
its implications for sampling and analysis of groundwater composition 
data, is appropriate for consistency with RCRA approaches and 
requirements and the statutory direction applicable to this rulemaking. 
We believe a confidence level of this rigor will make it necessary for 
operators to collect an appropriate amount of data that clearly 
demonstrates that the restored ISR aquifer is geochemically stable and 
that UMTRCA requirements have been met. The frequency of

[[Page 4179]]

sampling that will provide meaningful data must be determined from 
site-specific conditions, such as groundwater flow rates. Another 
consideration is that stability sampling may be misleading if the 
operator has not allowed sufficient time for the natural system to 
recover to the point where the injection-extraction cycle is no longer 
influencing groundwater flow parameters in the wellfield, particularly 
in the immediate area around the monitoring wells.
---------------------------------------------------------------------------

    \88\ See 40 CFR 264.97(h) & (i).
---------------------------------------------------------------------------

b. Where will the determination of stability be made?
    We have noted that a restored ISR wellfield essentially functions 
as a RCRA hazardous waste management unit. In this sense, when 
restoration is completed successfully, and the chemistry of the 
groundwater has been returned to a reducing environment, the uranium 
and other constituents that were mobilized are essentially ``locked 
in'' to the subsurface, as are hazardous constituents that are 
contained by RCRA engineered units. Following this reasoning, it might 
be considered appropriate for the outer boundary of the restored ISR 
wellfield to be designated as the point of compliance with the 
groundwater standards. However, we are not proposing to take this 
approach.
    Today we are proposing that each well within the wellfield be 
considered for use as a point of compliance for purposes of determining 
stability after restoration is determined to be complete (note that 
today's proposal does not address the point of compliance for the 
regulatory agency's determination that restoration is complete, which 
may be a more complicated matter). We believe that this is appropriate 
given the size of some wellfields (on the order of hundreds of acres) 
and the significant variability that is typically present in the 
mineralized zone. We believe such an approach will more readily inform 
both the operator and regulatory agency of localized trending, which 
may then be remedied as appropriate. If the licensee is able to 
demonstrate that a particular well is sufficiently representative of 
groundwater conditions in a larger area, the regulatory agency may 
approve the use of one well to demonstrate stability in the area 
covered by a larger number of wells.

F. Institutional Control

    Institutional controls are intended to maintain long-term 
cognizance of the nature and location of particular activities that 
were done at a specific site, in this case the location of the uranium 
ore zone exploited by an ISR process. Institutional controls can 
prevent inadvertent intrusions or adverse consequences for future use 
of the site. Institutional controls are commonly described as active or 
passive. Active controls are measures such as guards and fences posted 
around a site. Passive controls could be the erection of signs or 
placards at a site.
    We are not proposing to establish institutional controls for ISR 
facilities. Active maintenance of the site will cease with the 
termination of the license, which will occur when the regulatory agency 
determines that all license conditions have been met. In this sense, we 
do not view the long-term stability monitoring period as an 
institutional control following the ISR restoration phase; rather, we 
view it as a period of active surveillance to determine the long-term 
success of the restoration effort.
    Nor are we proposing to establish passive controls, either at the 
site or in documents such as local land records. Requirements for 
survey plats or other records to be maintained would be consistent with 
RCRA requirements for hazardous waste facilities; however, these 
typically apply when waste management units remain at the site and are 
intended to restrict disturbance of the site.\89\ Though we are not 
proposing that such records be established for ISR sites, we strongly 
encourage NRC and Agreement States to include such provisions in ISR 
licenses since ISR sites will not be restricted from sale or further 
development. Such provisions could simply inform the subsequent owner 
of the previous ISR, groundwater restoration activities and aquifer 
exemption on the property.
---------------------------------------------------------------------------

    \89\ See 40 CFR 264.116 and 264.119.
---------------------------------------------------------------------------

G. Other Proposed Amendments

    EPA has identified several non-ISR related provisions within 40 CFR 
part 192 that should be updated and amended. The issues that we propose 
to address today include:
    <bullet> Amending Sec.  192.32 to address a ruling of the Tenth 
Circuit Court of Appeals;
    <bullet> Deleting reference to Grand Junction Remedial Action 
Criteria (10 CFR 712) at Sec.  192.20(b)(3) since the criteria have 
been removed from the Code of Federal Regulations (CFR); and
    <bullet> Correcting minor typographical and grammatical errors 
found in Sec. Sec.  192.31 and 192.32.
1. Judicial Decisions
    Section 192.32 has been affected by a ruling from the Tenth Circuit 
Court of Appeals. Under Sec.  192.32(a)(2)(v), NRC was required to 
obtain EPA concurrence for approval of ACLs in groundwater restoration. 
This provision was effectively struck down by the Tenth Circuit Court 
of Appeals in Environmental Defense Fund v. U.S. Nuclear Regulatory 
Commission, 866 F.2d 1263, 1268-1269 (10th Cir. 1989), when the Court 
ruled that NRC has authority under AEA section 84(c) to independently 
make these site-specific ACL determinations, and that NRC has no duty 
to obtain this EPA concurrence. Therefore, today we are proposing to 
revise 40 CFR 192.32(a)(2)(v) by deleting this EPA concurrence 
requirement.
2. Miscellaneous Updates and Corrections
    EPA is proposing an amendment to address an area of part 192 where 
reference is made to another environmental regulation that has since 
been removed from the CFR. EPA is also proposing several technical 
corrections to address known typographical and grammatical errors.
a. Outdated Cross-Reference
    Section 192.20(b)(3) refers to criteria that no longer exist in the 
CFR. Because of this, EPA is proposing to eliminate reference to the 
Grand Junction Remedial Action Criteria, which once existed at 10 CFR 
part 712.
    In addition, language in Sec.  192.20(b)(3) cites methods that did 
not prove effective during the Grand Junction Remedial Action 
Program.\90\ The final report for the program clearly states that 
filtration (by high efficiency filters or by electrostatic 
precipitators) and sealants (mainly epoxy-based resins) were not 
effective over the long term, and were not recommended as remedial 
options for radon mitigation.\91\ EPA proposes to eliminate the 
language referencing sealants and filtration.
---------------------------------------------------------------------------

    \90\ In 1972, Public Law 92-314 created the Grand Junction 
Remedial Action Program to reduce radiation exposures inside 
structures affected by uranium tailings. The U.S. Surgeon General 
published cleanup guidelines for the voluntary project.
    \91\ Colorado Department of Health (1989). ``Final Report on the 
Grand Junction Remedial Action Program.''
---------------------------------------------------------------------------

b. Technical Corrections
    Since promulgation of 40 CFR part 192, several typographical and 
grammatical errors have been identified. Today, EPA is proposing 
amendments in Sec. Sec.  192.31(a), 192.31(f) and 192.32(a)(2)(v) to 
address these technical errors (e.g., spelling mistakes, misplaced 
comma).

[[Page 4180]]

V. Summary of Environmental, Cost and Economic Impacts

A. What are the impacts to groundwater?

    EPA has conducted a qualitative assessment of the benefits of the 
proposed rule and the expected effects on human and environmental 
health.\92\ The rule would require thorough characterization of 
background groundwater conditions within the ore zone and surrounding 
aquifers, and would put in place an automatic updating feature so that 
the requirements affecting ISR operations are always consistent with 
requirements of the SDWA and the RCRA. The proposed rule would also 
require a longer period of monitoring, 30 years, to ensure that 
conditions in the exempted aquifer had been restored, achieved steady-
state and remain stable. Further, EPA allows facilities to use 
geochemical modeling to demonstrate that groundwater conditions will 
remain stable, and thereby reduce the duration of stability monitoring 
to less than 30 years. These provisions help to ensure that, after the 
ISR operation's license is terminated and the site is closed, 
groundwater conditions do not deteriorate. Since a closed ISR facility 
has no regulatory oversight, EPA expects that the improved monitoring 
program being proposed will reduce the risk of contaminating valuable 
groundwater resources, thus also reducing unintended exposure of human 
and ecological receptors to radiological and non-radiological 
constituents in groundwater. To the extent that such exposures are 
reduced, associated human health risks such as cancer may also be 
reduced.
---------------------------------------------------------------------------

    \92\ See EPA (2014). ``Economic Analysis: Proposed Revisions to 
the Health and Environmental Protection Standards for Uranium and 
Thorium Mill Tailings Rule (40 CFR part 192).'' This document which 
can be found in the docket for this proposed rule. (Docket EPA-HQ-
OAR-2012-0788).
---------------------------------------------------------------------------

    Groundwater is a valuable resource, particularly in the Western 
United States where uranium ISR is most common. Although EPA is unable 
to quantify the value of the groundwater resources that would be 
protected by the proposed rule, EPA nevertheless believes that the 
groundwater resources are likely to become more valuable over time. 
Reducing the risk of contamination of groundwater also protects surface 
water bodies to which affected aquifers discharge. If groundwater near 
an ISR facility were to become contaminated due to re-mobilization of 
uranium and other constituents, it might be many years before the 
contamination was discovered, especially under current practice where 
stability monitoring only lasts a year or two. Benefits associated with 
protecting other potential services provided by groundwater are also 
expected.\93\
---------------------------------------------------------------------------

    \93\ See Committee on Valuing Ground Water, National Research 
Council (1997), ``Valuing Ground Water: Economic Concepts and 
Approaches,'' which discusses both the extraction value (e.g., value 
of groundwater used for drinking water, industrial water supply, and 
agriculture) and the value of in situ services (e.g., buffer against 
periodic shortages in surface water supplies, protect water quality 
by maintaining the capacity to dilute and assimilate groundwater 
contaminants, etc.).
---------------------------------------------------------------------------

B. What are the benefits of avoiding impacts to groundwater?

    In order to illustrate the potential benefits of avoiding impacts 
to groundwater, EPA estimated the costs of corrective action that would 
be required if uranium and other constituents remobilized in 
groundwater over time, resulting in contamination.\94\ By preventing 
groundwater contamination (or causing it to be discovered sooner), the 
proposed rule reduces the corrective action costs incurred to remediate 
the contamination. Based on groundwater contamination simulations 
(using a model facility approach under varying assumptions), the cost 
of remediation would far exceed the costs of complying with the 
proposed rule, both on an annual and total basis. Using a hydrological 
model, EPA estimated that cleaning up the plume of contamination could 
require 100 years of pump and treat remediation. In addition, if 
contamination were detected after decommissioning of a site, it is 
possible that the costs of remediation would be borne by the taxpayer 
or by the owner of the property, rather than by the uranium company 
responsible. Because we cannot anticipate how many ISR operations might 
experience deteriorating groundwater conditions after decommissioning 
or how long it would be before the contamination would be detected, EPA 
was unable to estimate potential avoided costs of remediation on a 
national scale. However, EPA believes they could be substantial.
---------------------------------------------------------------------------

    \94\ See EPA (2014). ``Economic Analysis: Proposed Revisions to 
the Health and Environmental Protection Standards for Uranium and 
Thorium Mill Tailings Rule (40 CFR part 192).''
---------------------------------------------------------------------------

C. What are the cost impacts?

    Using information about the uranium extraction industry and 
estimated incremental costs that would result from the rule as proposed 
today, EPA examined the economic impacts that may result from the 
revisions to 40 CFR part 192.\95\
---------------------------------------------------------------------------

    \95\ EPA (2014). ``Economic Analysis: Proposed Revisions to the 
Health and Environmental Protection Standards for Uranium and 
Thorium Mill Tailings Rule (40 CFR part 192).''
---------------------------------------------------------------------------

    EPA's study estimates that affected ISR operators would incur costs 
to comply with the proposed rule, which would require comprehensive 
pre-operational characterization of the site (including 
characterization of geochemical conditions downgradient of the 
production zone), careful monitoring during the operation, restoration 
of groundwater quality, at least three years of stability monitoring, 
and 30 years of long-term stability monitoring, with the potential to 
shorten the duration based on modeling and monitoring of downgradient 
geochemical conditions. Using existing ISR operations as models for ISR 
operations that would be affected by the rule, projecting that 2015 ISR 
uranium production will be 9.5 million pounds, and using average 
estimated costs of complying with the proposed rule, EPA estimates that 
the proposed rule would increase the average cost of uranium production 
at ISR facilities by approximately $1.50 per pound of uranium (2.9%), 
and that annual costs incurred by individual ISR facilities would vary 
from $304,000 to $9.5 million, depending on the scale of the ISR 
facility. Nationally, EPA estimates that the incremental total annual 
cost of the proposed rule would be approximately $13.5 million. 
Discounted at 7%, the estimated present value of the stream of national 
costs would be approximately $181 million. Discounted at 3%, the 
estimated present value of national costs would be approximately $290 
million.
    EPA estimated the impact of the proposed rule on the market for 
uranium using a simplified model of the U.S. market for uranium in 
2015. The partial equilibrium model estimated market impacts and 
revealed: (a) Changes in the quantity of uranium purchased by U.S. 
civilian owners and operators of nuclear power plants, (b) changes in 
the domestic sales of uranium and imports, and (c) changes in the 
market price for uranium. EPA found that overall, the market quantity 
of uranium purchased for use in electric generation would decline by 
less than 0.1% and the market price would increase by approximately 
0.4%. Domestic ISR facilities would decrease their production by 
approximately 3.8%, and imports of uranium would increase by less than 
1%. Because the cost of uranium is a very small share of

[[Page 4181]]

the cost of electricity, EPA estimates that the cost of generating 
electricity would increase by less than 0.1%. Although the national 
total annual cost of the proposed rule (approximately $13.5 million, 
based on average costs) is well below the $100 million threshold that 
is one of the criteria used to identify a significant regulatory 
action, the industry has only a small number of companies operating a 
small number of ISR operations. EPA used existing ISR operations and 
the companies that own them as models for the types of facilities and 
companies that would potentially be affected by the proposed rule. EPA 
thus estimated that individual ISR facilities could incur annual costs 
of compliance between $304,000 and $9.5 million, depending on the 
characteristics of the ISR facility and the costing assumptions 
used.\96\ For small firms owning ISR facilities, EPA's analysis 
estimates cost-to-sales ratios of 0.6% to 1.7%. Because costs are 
generally less than 2% of company sales, EPA estimates that compliance 
costs would not cause a significant impact. Further, EPA estimates that 
only a few small businesses (ten or fewer, based on current 
information) would be affected by the proposed rule at a given time. 
Thus, EPA concludes that the rule would not have a significant impact 
on a substantial number of small entities.
---------------------------------------------------------------------------

    \96\ See sensitivity analysis results in Table D-1 of EPA 
(2014). ``Economic Analysis: Proposed Revisions to the Health and 
Environmental Protection Standards for Uranium and Thorium Mill 
Tailings Rule (40 CFR part 192).'' The total estimated wellfield 
acreage for most ISR operations is under 500 acres (see Table 3-7 of 
EPA EA(2014). ``Economic Analysis: Proposed Revisions to the Health 
and Environmental Protection Standards for Uranium and Thorium Mill 
Tailings Rule (40 CFR part 192).''
---------------------------------------------------------------------------

VI. Statutory and Executive Orders Review

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
action is a ``significant regulatory action.'' The Executive Order 
defines ``significant regulatory action'' as one that is likely to 
result in a rule that may ``raise novel legal or policy issues arising 
out of legal mandates, the President's priorities, or the principles 
set forth in the Executive Order.''
    Accordingly, EPA submitted this action to the Office of Management 
and Budget (OMB) for review under Executive Orders 12866 and 13563 (76 
FR 3821, January 21, 2011) and any changes made in response to OMB 
recommendations have been documented in the docket for this action.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under 
the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.; 
no reporting requirements are imposed on affected facilities by this 
rule. This rule will not in-and-of itself create any new information 
collection requirements that require approval of the OMB.
    Burden means the total time, effort, or financial resources 
expended by persons to generate, maintain, retain, or disclose or 
provide information to or for a Federal agency. This includes the time 
needed to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business whose 
company has less than 500 employees and is primarily engaged in 
leaching or beneficiation of uranium, radium or vanadium ores as 
defined by NAIC code 212291; (2) a small governmental jurisdiction that 
is a government of a city, county, town, school district or special 
district with a population of less than 50,000; and (3) a small 
organization that is any not-for-profit enterprise which is 
independently owned and operated and is not dominant in its field. Of 
these three categories, only small businesses are potentially affected 
by the proposed rule; no small organizations or small governmental 
entities have been identified that would be impacted by the proposed 
revisions to part 192.
    This proposed rule is estimated to impact approximately 18 uranium 
recovery facilities that are currently operating or may operate in the 
near future. The 18 uranium recovery facilities are owned by 10 firms, 
of which eight are believed to be small.
    The proposed revisions to 40 CFR part 192 would apply to the six 
ISRs operating in 2013. These ISRs are as follows: (1) Crow Butte 
(Nebraska) and (2) Smith Ranch-Highland (Wyoming), owned by Cameco 
Resources; (3) Alta Mesa (Texas), owned by Mestena Uranium, LLC; (4) 
Willow Creek (Wyoming), owned by Uranium One, Inc.; (5) Hobson-La 
Palangana (Texas), owned by Uranium Energy Corp.; and(6) Lost 
Creek(Wyoming), owned by Ur-Energy Inc. Using the fewer than 500 
employees' criterion Mestena Uranium, LLC, Ur-Energy, Inc., and Uranium 
Energy Corp. qualify as small businesses, while Cameco Resources and 
Uranium One, Inc. are both large businesses.
    In addition to the six ISRs operating in 2013, an additional ISR 
has been licensed in the state of Wyoming: Nichols Ranch, owned by 
Uranerz Uranium Corp. Uranerz Uranium Corp. qualifies as small 
business.
    Eleven other ISRs are at some stage of licensing or permitting, or 
are undergoing restoration. These include: (1) Dewey-Burdock in South 
Dakota owned by Powertech Uranium Corp.; (2) Moore Ranch in Wyoming, 
owned by Uranium One, Inc.; (3) Kingsville Dome, (4) Rosita, and (5) 
Vasquez, all in Texas and owned by Uranium Resources Inc.; (6) 
Crownpoint and (7) Church Rock, both in New Mexico and owned by Uranium 
Resources Inc.; (8) Ross in Wyoming, owned by Strata Energy, Inc., (9) 
Goliad in Texas, owned by Uranium Energy Corp.; (10) Antelope-Jab in 
Wyoming, owned by Uranium One, Inc., and (11) Reno Creek in Wyoming, 
owned by Bayswater E&P. All of these companies, except for Uranium One, 
Inc., are small businesses.
    To evaluate the significance of the economic impacts of the 
proposed revisions to 40 CFR part 192, EPA estimated the costs that 
would be incurred by existing facilities, based on their estimated 
production and EPA's estimated cost per pound of U3O8.

[[Page 4182]]

    Of the 18 ISR facilities identified above, 13 are owned by a total 
of eight small businesses; the other five are owned by two large 
businesses. EPA's economic impact analysis estimated that for the three 
small firms currently operating ISR facilities, costs of the proposed 
rule would range from 0.6% to 1.7% of estimated company sales, 
depending on the costing assumption used. Because the costs are 
generally estimated to be less than 2% of sales, impacts for these 
firms would not be significant. In addition, fewer than 10 small firms 
are likely to be affected by the proposed rule at any time, so the 
number of firms potentially incurring costs to comply with the rule is 
not a substantial number. Thus, EPA concludes that the proposed rule 
would not result in a significant impact to a substantial number of 
small entities.
    No small organizations or small governmental entities have been 
identified that would be impacted by the proposed revisions to 40 CFR 
part 192. We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.
    After considering the economic impacts of this proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities.

D. Unfunded Mandates Reform Act

    This rule does not contain a Federal mandate that may result in 
expenditures of $100 million or more for State, local and Tribal 
governments, in the aggregate, or the private sector in any one year. 
Using the six ISR operations operating in 2013 as examples of typical 
ISR facilities, EPA estimates that total annual costs of complying with 
the rule for six such ISR facilities, would be $13.5 million. The 
proposed rule imposes no enforceable duties on any State, local or 
Tribal governments or the private sector. Thus, this rule is not 
subject to the requirements of sections 202 or 205 of UMRA.
    This rule is also not subject to the requirements of section 203 of 
UMRA because it contains no regulatory requirements or obligations that 
might significantly or uniquely affect small governments; the rule does 
not contain requirements that apply to such governments nor does it 
impose obligations upon them.

E. Executive Order 13132: Federalism

    This proposed rule does not have federalism implications. It will 
not have substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government, 
as specified in Executive Order 13132. None of the facilities subject 
to this action are owned and operated by State governments, and nothing 
in the proposed rule will supersede State regulations. Thus, Executive 
Order 13132 does not apply to this proposed rule.
    EPA recognizes that Agreement States will have a substantial 
interest in this rule revision since they have primary responsibility 
for implementation of 40 CFR part 192 standards. In the spirit of 
Executive Order 13132 and consistent with EPA policy to promote 
communications between EPA and State and local governments, EPA 
specifically solicits comment on this proposed rule from State and 
local officials.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications, as specified in 
Executive Order 13175 (65 FR 67249, November 9, 2000). The action 
imposes requirements on licensees of ISR facilities and not tribal 
governments. Although Executive Order 13175 does not apply to this 
action, EPA sought opportunities to provide information to tribes and 
tribal representatives during the review of 40 CFR part 192. EPA 
specifically solicits additional comment on this proposed action from 
tribal officials.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) 
as applying to those regulatory actions that concern health or safety 
risks, such that the analysis required under section 5-501 of the Order 
has the potential to influence the regulation. Because this action 
addresses environmental standards intended to mitigate health or safety 
risks, it is subject to Executive Order 13045. We evaluated several 
regulatory strategies for assuring groundwater restoration and 
stability at ISR facilities and selected the option providing most 
assurance that groundwater systems will remain in a chemically reduced 
state, thereby limiting contamination of groundwater. The proposed rule 
is expected to reduce children's risk of exposure to contaminated 
groundwater by improving monitoring to detect and correct 
contamination.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355, May 22, 2001), because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. This proposed rule will not adversely 
directly affect productivity, competition, or prices in the energy 
sector.

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies. NTTAA directs EPA to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This proposed rulemaking does not involve technical standards of 
the type indicated in NTTAA. Therefore, EPA is not considering the use 
of any voluntary consensus standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, Feb. 16, 1994) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this proposed rule will not have 
disproportionately high and adverse human health or environmental 
effects on minority or low-income populations because it increases the 
level of environmental protection for all affected populations without 
having any

[[Page 4183]]

disproportionately high and adverse human health or environmental 
effects on any population, including any minority or low-income 
population. This proposed rule addresses groundwater restoration, 
monitoring and protection of surrounding aquifers and thus decreases 
the potential groundwater contamination to which all affected 
populations are exposed. Thus, the proposed rule is projected to have 
positive, not adverse impacts on human health and the environment.

List of Subjects in 40 CFR Part 192

    Environmental protection, Hazardous substances, Radiation 
protection, Radioactive materials, Reclamation, Uranium, Waste 
treatment and disposal, Water resources.

    Dated: December 31, 2014.
Gina McCarthy,
Administrator.

    For the reasons stated in the preamble, the Environmental 
Protection Agency proposes to amend title 40, Chapter I of the Code of 
Federal Regulations as follows:

PART 192--[AMENDED]

0
1. The authority citation for 40 CFR part 192 continues to read as 
follows:

    Authority:  Sec. 275 of the Atomic Energy Act of 1954, 42 U.S.C. 
2022, as added by the Uranium Mill Tailings Radiation Control Act of 
1978, Pub. L. 95-604, as amended.

0
2. Section 192.20 is amended by revising paragraph (b)(3)as follows:

Subpart C--[Amended]


Sec.  192.20  Guidance for implementation.

* * * * *
    (b) * * *
    (3) Compliance with Sec.  192.12(b) may be demonstrated by methods 
that the Department of Energy has approved for use or methods that the 
implementing agencies determine are adequate. Residual radioactive 
materials should be removed from buildings exceeding 0.03 WL so that 
future replacement buildings will not pose a hazard [unless removal is 
not practical--see Sec.  192.21(c)]. However, ventilation devices and 
other radon mitigation methods recommended by EPA may provide 
reasonable assurance of reductions from 0.03 WL to below 0.02 WL. In 
unusual cases, indoor radiation may exceed the levels specified in 
Sec.  192.12(b) due to sources other than residual radioactive 
materials. Remedial actions are not required in order to comply with 
the standard when there is reasonable assurance that residual 
radioactive materials are not the cause of such an excess.
* * * * *

Subpart D--[Amended]

0
3. The heading for Subpart D is amended by revising the language to 
read as follows:

Subpart D--Standards for the Management of Uranium Byproduct 
Materials

0
4. Section 192.31 is amended by:
0
a. Revising paragraph (a).
0
b. Revising paragraph (f).
0
c. Revising the second sentence of paragraph (m).
    The revisions read as follows:

Subpart D--Standards for the Management of Uranium Byproduct 
Materials

* * * * *


Sec.  192.31  Definitions and cross-references.

    (a) Unless otherwise indicated in this subpart, all terms shall 
have the same meaning as in Title II of the Uranium Mill Tailings 
Radiation Control Act of 1978, subparts A and B of this part, or parts 
190, 260, 261, and 264 of this chapter. For the purposes of this 
subpart, the terms ``waste,'' ``hazardous waste,'' and related terms, 
as used in parts 260, 261, and 264 of this chapter, shall apply to 
byproduct material.
* * * * *
    (f) Disposal area means the region within the perimeter of an 
impoundment or pile containing uranium byproduct materials to which the 
post-closure requirements of Sec.  192.32(b)(1) of this subpart apply.
* * * * *
    (m) * * * This term shall not be construed to include extraordinary 
measures or techniques that would impose costs that are grossly 
excessive as measured by practice within the industry or one that is 
reasonably analogous (such as, by way of illustration only, 
unreasonable overtime, staffing or transportation requirements, etc., 
considering normal practice in the industry; laser fusion of soils, 
etc.), provided there is reasonable progress toward emplacement of a 
permanent radon barrier. * * *
* * * * *
0
5. Section 192.32 is amended by revising paragraph (a)(2)(v) as 
follows:


Sec.  192.32  Standards

* * * * *
    (a) * * *
    (2) * * *
    (v) The functions and responsibilities designated in part 264 of 
this chapter as those of the ``Regional Administrator'' with respect to 
``facility permits'' shall be carried out by the regulatory agency.
* * * * *
0
6. Part 192 is amended by adding subpart F to read as follows:
Subpart F--Public Health, Safety and Environmental Protection Standards 
for Byproduct Materials Produced by Uranium In-situ Recovery
Sec.
192.50 Applicability.
192.51 Definitions and cross-references.
192.52 Standards.
192.53 Monitoring programs.
192.54 Corrective action program.
192.55 Effective date.

Subpart F--Public Health, Safety and Environmental Protection 
Standards for Byproduct Materials Produced by Uranium In-Situ 
Recovery


Sec.  192.50  Applicability.

    This subpart applies to the management of uranium byproduct 
materials prior to, during and following the processing of uranium ores 
utilizing uranium in-situ recovery methods, and to the restoration of 
groundwater at such sites. Unless otherwise specified, all wellfields 
shall comply with this subpart as of the effective date of this rule.


Sec.  192.51  Definitions and cross-references.

    (a) Unless otherwise indicated in this subpart, all terms shall 
have the same meaning as in Title II of the Uranium Mill Tailings 
Radiation Control Act of 1978, subparts A, B, and D of this part, or 
parts 190, 260, 261, and 264 of this chapter.
    (b) Adjacent Aquifer. 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.
    (c) Alternate Concentration Limit (ACL). Concentration limit 
approved by the regulatory agency for a groundwater constituent that 
has not been restored to its restoration goal after best practicable 
restoration activities have been completed following the process 
prescribed in 40 CFR 192.52(c)(2) thru 192.52(c)(5) of this subpart.
    (d) Aquifer. A geological ``formation,'' group of formations, or 
part of a formation that is capable of yielding a significant amount of 
water to a well or spring. See 40 CFR 144.3.
    (e) Background. The condition of groundwater, including the 
radiological and non-radiological constituent concentrations, in the 
exempted aquifer, adjacent aquifers, and in both overlying and 
underlying aquifers, prior to the beginning of ISR operations.

[[Page 4184]]

    (f) Constituent. A detectable component within the groundwater.
    (g) Exceedance. An exceedance has occurred when, during stability 
or long-term stability monitoring, a groundwater protection standard is 
exceeded at any point of compliance well.
    (h) Excursion. The movement of fluids containing uranium byproduct 
materials from an ISR production zone into surrounding groundwater. An 
excursion is considered to have occurred when, during operational or 
restoration phase monitoring, any two indicator parameters (e.g., 
chloride, conductivity, total alkalinity) exceed their respective upper 
control limits in any overlying, underlying, or perimeter monitoring 
well. Horizontal excursions refer to the lateral movement of the water, 
while vertical excursions indicate movement of water through aquitards 
above or below the production zone aquifer.
    (i) Excursion Monitoring Wells. Wells located around the perimeter 
of the production zone (horizontal excursion wells) and in overlying 
and underlying aquifers (vertical excursion wells), which are used to 
detect any excursions from the production zone. Excursion monitoring 
wells can serve as the ``point(s) of compliance'' during all phases of 
ISR.
    (j) Exempted Aquifer. An ``aquifer,'' or its portion, that meets 
the criteria of ``underground source of drinking water'' in 40 CFR 
144.3, but which has been exempted according to the procedures in 40 
CFR 144.7. See 40 CFR 144.3.
    (k) Extraction Well. Well used to extract uranium enriched 
solutions from the ore-bearing aquifer; also known as a ``Production 
Well.'' Extraction and injection wells may be converted from one use to 
the other.
    (l) Indicator Parameter. A constituent, such as chloride, 
conductivity, or total alkalinity, whose ``upper control limit'' is 
used to identify an excursion. Indicator parameters are not 
contaminants, but relate to geochemical conditions in groundwater.
    (m) Injection Well. A well into which fluids are being injected. 
See 40 CFR 144.3.
    (n) In-Situ Recovery (ISR). A method of extraction 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 body. The process does not require the extraction of ore from the 
ground. The lixiviant is injected, passes through the ore body, 
mobilizes the uranium, and the uranium-bearing solution is pumped to 
the surface from extraction wells. The pregnant leach solution is 
processed to extract the uranium.
    (o) Listed Constituent. One of the thirteen groundwater 
constituents specified in Table 1 to subpart F of part 192.
    (p) Lixiviant. A liquid medium used to recover uranium from 
underground ore bodies through in-situ recovery. This liquid medium 
typically contains native groundwater and an added oxidant, such as 
oxygen and/or hydrogen peroxide, as well as sodium carbonate/
bicarbonate or carbon dioxide. The lixiviant is introduced through 
injection wells into the ore body to mobilize the uranium. The 
resulting solution is then pumped via extraction wells to the surface, 
where the uranium is recovered from the solution for further 
processing, after which the lixiviant may be re-injected.
    (q) Long-Term Stability Phase. The period after the groundwater 
protection standards have been met and stability has been demonstrated 
according to 192.53(d) of this subpart, as determined by the regulatory 
agency.
    (r) Maximum Constituent Concentration. The maximum permissible 
level of a constituent in groundwater, as specified in Table 1 to 
subpart A of part 192.
    (s) Maximum Contaminant Level (MCL). The maximum permissible level 
of a contaminant in water which is delivered to any user of a public 
water system. See 40 CFR 141.2.
    (t) Monitoring Wells. Wells used to obtain groundwater levels and 
water samples for the purpose of determining the hydrologic regime and 
the amounts, types, and distribution of constituents in the 
groundwater. Wells are located in the production zone, around the 
perimeter of the production zone (horizontal excursion monitoring 
wells), and in overlying and underlying aquifers (vertical excursion 
monitoring wells).
    (u) Operational Phase. The time period during which uranium 
extraction by in-situ recovery occurs. Operations begin when injection 
of lixiviant starts. Operations end when the operator permanently 
ceases injection of lixiviant and recovery of uranium-bearing solution 
for processing purposes.
    (v) Overlying Aquifer. An aquifer that is immediately vertically 
shallower (i.e., directly above) than the production zone aquifer.
    (w) Point(s) of Compliance. Site-specific location(s) where 
groundwater protection standards must be met. During all phases of ISR, 
excursion monitoring wells can serve as the points of compliance; 
during the restoration, stability and long-term stability phases, 
points of compliance may also include monitoring, injection and 
extraction wells in the production zone, as determined by the 
regulatory agency.
    (x) Point(s) of Exposure. Intersection of a vertical plane with the 
boundary of the exempted aquifer.
    (y) Preoperational Monitoring. Measurement of groundwater 
conditions in the production zone, and in the groundwater up and down 
gradient from the production zone, as well as in overlying and 
underlying aquifers, prior to the operational phase.
    (z) Production Zone. The portion of the aquifer in which ISR 
activities occur. The production zone lies within the wellfield.
    (aa) Restoration (Act of). The process of returning groundwater 
quality to preoperational conditions for the purpose of achieving 
restoration goal values for identified constituents.
    (bb) Restoration Goal. A concentration limit for an identified 
constituent in groundwater after restoration has occurred. The limit is 
obtained from the most protective regulatory standards in 40 CFR 
141.62, 141.66, 141.80, 143.3, 264.94, and Table 1 to subpart A of this 
part, and from preoperational background levels in the wellfield, 
whichever is higher.
    (cc) Restoration Phase. The period immediately after lixiviant 
injection permanently ceases, during which restoration activities 
occur.
    (dd) Site. The land or water area where any facility or activity is 
physically located or conducted, including adjacent land used in 
connection with the facility or activity. See 40 CFR 144.3.
    (ee) Stability Phase. The period after the restoration phase when 
groundwater protection standards are met and monitored to test for 
temporal stability.
    (ff) Underlying Aquifer. An aquifer that is immediately vertically 
deeper (i.e., directly below) than the production zone aquifer.
    (gg) Upper Control Limit (UCL). Preoperational concentrations of 
indicator parameters in horizontal and vertical excursion monitoring 
wells, as determined by the regulatory agency and contained in the 
license.
    (hh) Uranium Recovery Facility. A facility licensed to process 
uranium ores for the purpose of recovering uranium and to manage 
uranium byproduct materials that result from processing of ores. Common 
names for these facilities include, but are not limited to, the 
following: A conventional uranium mill, an in-situ recovery (or leach) 
facility, and a heap leach facility or pile.
    (ii) Wellfield. The area of an ISR operation that encompasses the 
array of

[[Page 4185]]

injection, extraction, and monitoring wells, ancillary equipment and 
interconnected piping employed in the uranium in-situ recovery process. 
The area of the wellfield exceeds that of the production zone.


Sec.  192.52  Standards.

    (a) Except for those wellfields currently in and remaining in 
restoration, stability monitoring or long-term monitoring at a licensed 
facility, all operating wellfields, new wellfields and expansions of 
wellfields shall comply with Sec.  192.52(c) of this subpart as of the 
effective date of this rule.
    (b) Surface and subsurface standards. (1) Surface impoundments 
associated with ISR activities shall conform to the standards of Sec.  
192.32 of this part.
    (2) Disposal of solid uranium byproduct materials produced by ISR 
activities shall conform to the standards in Sec.  192.32 of this part.
    (c) Groundwater protection standards. (1) Restoration goals shall 
be determined for each of the constituents listed in Table 1 to subpart 
F that is identified in the groundwater. Following restoration 
activities in the production zone, and prior to license termination, 
the concentration of a listed constituent in the groundwater within the 
production zone, as determined by the regulatory agency, must not 
exceed the higher of the following values:
    (i) The background level of that constituent in the groundwater, as 
determined by preoperational monitoring conducted under Sec.  192.53(a) 
of this subpart; or
    (ii) The lowest concentration listed in 40 CFR 141.61, 141.62, 
141.66, 141.80, 143.3, 264.94, or Table 1 to subpart A of this part for 
that constituent.
    (iii) When considering the potential for health risks caused by 
human exposure to known or suspected carcinogens not listed in Table 1 
to subpart F that are designated for monitoring by the regulatory 
agency, the restoration goal above the background level should be 
established at 40 CFR part 141, 143 or 264 concentration levels, if 
such values exist. For constituents that are not found in 40 CFR part 
141, 143 or 264, the restoration goal above the background level should 
be established at concentration levels which represent a cumulative 
excess lifetime risk no greater than 10<SUP>-4</SUP> to an average 
individual.
    (2) The regulatory agency may establish provisional alternate 
concentration limits within the production zone provided that all of 
the following conditions are met:
    (i) After all best practicable active restoration activities have 
been completed in accordance with the permit, the regulatory agency 
determines that concentrations for one or more constituents cannot be 
restored to restoration goals; and
    (ii) The constituent(s) will not pose a substantial present or 
potential hazard to human health or the environment as long as the 
proposed alternate concentration limit(s) is not exceeded; and
    (iii) In all cases, the restoration goals, as determined under 
paragraph (c)(1) of this section, are satisfied at all points of 
exposure.
    (3) The regulatory agency may approve final alternate concentration 
limits provided that the following conditions are met:
    (i) The licensee has demonstrated groundwater stability at 95 
percent confidence for three consecutive years (i.e., no increasing 
trend in concentration levels as identified by appropriate statistical 
techniques) of groundwater concentrations for the listed constituents 
before entering the long-term stability monitoring phase; and
    (ii) The constituent(s) will not pose a substantial present or 
potential hazard to human health or the environment as long as the 
proposed alternate concentration limit(s) is not exceeded.
    (4) In deciding whether to approve a provisional or a final 
alternate concentration limit, the regulatory agency shall consider, at 
a minimum, the following factors:
    (i) Potential adverse effects on groundwater quality, considering:
    (A) The physical and chemical characteristics of constituents in 
the groundwater at the site, including their potential for migration;
    (B) The hydrogeological characteristics (e.g., groundwater 
velocity) of the site and surrounding land;
    (C) The quantity of groundwater and the direction of groundwater 
flow;
    (D) The proximity and withdrawal rates of local groundwater users;
    (E) The current and anticipated future uses of groundwater in the 
region surrounding the site;
    (F) The existing quality of groundwater, including other sources of 
contamination and their cumulative impact on groundwater quality;
    (G) The potential for health risks caused by human exposure to 
constituents;
    (H) The potential damage to wildlife, crops, vegetation, and 
physical structures caused by exposure to constituents; and
    (I) The persistence and permanence of the potential adverse 
effects.
    (ii) Potential adverse effects on hydraulically-connected surface-
water quality, considering:
    (A) The volume and physical and chemical characteristics of the 
groundwater at the site;
    (B) The hydrogeological characteristics of the site and surrounding 
land;
    (C) The quantity and quality of groundwater, and the direction of 
groundwater flow;
    (D) The patterns of rainfall in the region;
    (E) The proximity of the site to surface waters;
    (F) The current and future uses of surface waters in the region 
surrounding the site and any water quality standards established for 
those surface waters;
    (G) The existing quality of hydraulically-connected surface water, 
including other sources of contamination and their cumulative impact on 
surface water quality;
    (H) The potential for health risks caused by human exposure to 
constituents;
    (I) The potential damage to wildlife, crops, vegetation, and 
physical structures caused by exposure to constituents; and
    (J) The persistence and permanence of the potential adverse 
effects.
    (iii) The presence of any underground source of drinking water as 
defined under Sec.  144.3 of this chapter and any exempted aquifer 
identified under Sec.  144.7 of this chapter.
    (5) When considering the potential for health risks caused by human 
exposure to known or suspected carcinogens, alternate concentration 
limits pursuant to paragraphs 192.52(c)(2) and 192.52(c)(3) of this 
subpart should be established at concentration levels which represent a 
cumulative excess lifetime risk no greater than 10<SUP>-4</SUP>, at a 
point of exposure, to an average individual.

[[Page 4186]]



     Table 1 To Subpart F--Maximum Concentration of Constituents for
              Groundwater Protection at ISR Facility Sites
------------------------------------------------------------------------
              Constituent                     Maximum concentration
------------------------------------------------------------------------
Arsenic, barium, cadmium, chromium,      The restoration goal is the
 lead, mercury, selenium, silver,         primary or secondary MCL
 nitrate (as N), molybdenum, radium-226   listed in 40 CFR 141.61,
 and radium-228 (combined), uranium       141.62, 141.66, 141.80, and
 (uranium-234, uranium-235 and uranium-   143.3, the maximum
 238 combined), gross alpha particle      concentration of hazardous
 activity (excluding radon and uranium).  constituents for groundwater
                                          protection under 264.94, or
                                          the maximum constituent
                                          concentration specified in
                                          Table 1 to Subpart A of this
                                          Part, whichever value is most
                                          stringent.
                                         Where a background
                                          concentration is determined to
                                          be higher than the most
                                          stringent value in the
                                          applicable regulations, the
                                          background concentration will
                                          serve as the restoration goal.
------------------------------------------------------------------------

Sec.  192.53  Monitoring programs.

    Licensees subject to this subpart must conduct a groundwater 
monitoring program, subject to approval by the regulatory agency, at 
prospective and licensed ISR sites and environs. This program shall 
address all phases of the site's activities and must be conducted as 
follows:
    (a) Preoperational phase monitoring. (1) A sufficient number of 
wells, at appropriate locations and depths, shall be installed in such 
a manner as to yield representative samples in order to define the 
groundwater flow regime and measure preoperational conditions and water 
quality for use in statistical tests during operations, restoration, 
stability and long-term stability.
    (2) All monitoring wells must be cased in a manner that maintains 
the integrity of the monitoring-well bore hole. This casing must be 
screened or perforated and packed with gravel or sand, where necessary, 
to enable collection of groundwater samples. The annular space (i.e., 
the space between the bore hole and well casing) above the sampling 
depth must be sealed to prevent contamination of samples and the 
groundwater.
    (3) The preoperational background monitoring effort shall include 
immediately overlying aquifers, immediately underlying aquifers, and 
background monitoring inside and outside of the exempted aquifer, 
including both the up and downgradient areas outside of the production 
zone.
    (4) During the monitoring effort, relevant data documenting 
geology, hydrology and geochemistry for radiological and non-
radiological constituents shall be collected, both in the production 
zone and in surrounding areas that may be affected by the ISR 
operations.
    (i) The monitoring effort shall be of sufficient duration of no 
less than one year and of sufficient scope to adequately characterize 
temporal and spatial variations in groundwater, and to account for 
impacts of well installation and development on background 
concentrations of constituents and values of indicator parameters, 
where applicable.
    (ii) Preoperational monitoring shall be focused on determining 
background concentrations of constituents and indicator parameters in 
the following locations:
    (A) Point of compliance wells within the proposed production zone;
    (B) Point of compliance wells immediately overlying and immediately 
underlying aquifers;
    (C) Point of compliance wells outside the production zone;
    (D) Point of compliance wells within the exempted aquifer; and
    (E) Point of compliance wells in upgradient and downgradient non-
exempt portions of the adjacent aquifer.
    (iii) The licensee shall employ appropriate statistical techniques 
to analyze background concentrations measured in individual wells 
within the proposed production zone for the purpose of determining 
restoration goals for groundwater restoration and long-term stability 
monitoring under Sec.  192.52(c)(1) of this subpart. As determined by 
the licensee and approved by the regulatory agency, background 
concentration limits may be representative of individual wells, 
multiple wells, or all wells within the proposed production zone.
    (iv) Radiological and non-radiological constituents to be monitored 
during the preoperational phase of an ISR facility shall include:
    (A) All constituents listed in Table 1 to this subpart;
    (B) Constituents and parameters necessary for geochemical 
calculations of groundwater chemistry and to model site performance in 
order to demonstrate that a stable groundwater chemistry state, as 
approved by the regulatory agency, has been achieved through 
restoration and is likely to persist in the long term; and
    (C) Any additional constituents or parameters required by the 
regulatory agency, including metals potentially mobilized by the 
recovery process.
    (b) Operational phase monitoring. (1) Indicator parameters, as 
established by the regulatory agency, shall be monitored in horizontal 
and vertical excursion monitoring wells determined by the regulatory 
agency throughout the operational phase of ISR activities.
    (2) If an excursion is detected, as determined by the regulatory 
agency and as evidenced by indicator parameters exceeding established 
upper control limits, all constituents listed in Table 1 of this 
subpart shall be monitored as part of the corrective action program set 
forth in Sec.  192.54 of this subpart until the excursion is 
controlled.
    (c) Restoration phase monitoring. (1) All constituents listed in 
Table 1 of this subpart and otherwise specified by the regulatory 
agency shall be monitored during active restoration; sampling should 
occur no less frequently than quarterly, or other time interval 
specified by the regulatory agency.
    (2) Indicator parameters, as established by the regulatory agency, 
shall be monitored in horizontal and vertical excursion monitoring 
wells determined by the regulatory agency throughout the restoration 
phase of ISR activities.
    (3) If an excursion is detected, as determined by the regulatory 
agency and as evidenced by indicator parameters exceeding established 
upper control limits, all constituents listed in Table 1 of this 
subpart shall be monitored as part of the corrective action program set 
forth in Sec.  192.54 of this subpart until the excursion is 
controlled.
    (d) Stability phase monitoring. (1) The constituents to be 
monitored throughout the stability phase of an ISR facility in points 
of compliance wells in the production zone, as determined by the 
regulatory agency, shall include:
    (i) All constituents listed in Table 1 of this subpart;
    (ii) Any additional constituents required by the regulatory agency, 
such as:

[[Page 4187]]

    (A) Constituents and parameters necessary for geochemical 
calculations of the groundwater chemistry in order to demonstrate that 
a stable groundwater chemistry has been achieved and is likely to 
persist in the long-term;
    (B) Components of the lixiviant fluids injected during uranium 
recovery and any fluids injected during restoration; or
    (C) Metals potentially mobilized by the uranium recovery process.
    (2) Through field measurements using the monitoring network 
established to meet the requirements of Sec.  192.53(a) of this 
section, observations and calculations, and applying appropriate 
statistical techniques, the licensee shall demonstrate that aquifer 
conditions within the production zone are stable.
    (i) Stability shall be demonstrated for three consecutive years at 
a 95 percent confidence interval, measured from the time at which 
sufficient data to determine statistical significance has been 
collected, and based on sampling no less frequently than quarterly.
    (ii) Individual wells within the production zone can be the point 
of compliance for the purpose of assessing stability, as approved by 
the regulatory agency.
    (iii) If the licensee finds that the stability of groundwater 
meeting the concentration limits determined in Sec.  192.52(c)(1) of 
this subpart cannot be demonstrated for three consecutive years for one 
or more constituents, the regulatory agency may:
    (A) Require the licensee to resume active restoration efforts; or
    (B) Depending on the significance of the departure from the 
groundwater protection standards determined in Sec.  192.52(c)(1) of 
this subpart, approve a provisional alternate concentration limit 
according to the requirements of Sec.  192.52(c)(2) of this subpart. 
Once stability has been documented for three consecutive years, the 
regulatory agency may approve a final alternate concentration limit 
according to the requirements of Sec.  192.52(C)(3) of this subpart.
    (3) If an exceedance occurs, as determined by the regulatory agency 
and as evidenced by exceeding groundwater protection standards in 
192.52(c) of this subpart at point of compliance wells, all 
constituents listed in Table 1 of this subpart shall be monitored as 
part of the corrective action program set forth in Sec.  192.54 of this 
subpart until the exceedance is controlled.
    (e) Long-term stability phase monitoring. (1) Through field 
measurements utilizing the monitoring network established to meet the 
requirements of Sec.  192.53(a) of this section, observations and 
calculations, and applying appropriate statistical techniques, the 
licensee shall demonstrate that post-restoration aquifer conditions 
within the production zone remain stable and continue to show 
compliance with groundwater protection standards established under 
Sec.  192.52(c) of this subpart.
    (i) Stability and groundwater protection compliance shall be 
demonstrated based on sampling no less frequently than quarterly, or 
other time interval approved by the regulatory agency.
    (ii) Specific, individual wells within the production zone and 
approved by the regulatory agency shall be the points of compliance for 
the purpose of assessing stability and groundwater protection 
compliance, as approved by the regulatory agency.
    (iii) Long-term stability monitoring shall be conducted for a 
period of 30 years. The regulatory agency may shorten the long-term 
stability monitoring period if, after stability is documented for a 
period of three consecutive years as described under Sec.  192.53(d), 
the licensee demonstrates through geochemical modeling of the site that 
the subsurface conditions within the production zone will remain stable 
into the future. In evaluating such modeling, the regulatory agency 
must determine that there is a reasonable assurance that restoration 
goals will continue to be met and that subsurface conditions in the 
future will not cause the re-mobilization of uranium, radium or other 
constituents into the groundwater.
    (2) If one or more monitored groundwater constituents in a point of 
compliance well within the wellfield exceeds a groundwater protection 
standard as defined in 192.52(c), or one or more monitored constituents 
in a point of compliance well within the wellfield show statistically 
significant increasing trends that would threaten groundwater quality 
if left unabated, then the licensee must submit a report to the 
regulatory agency within 60 days describing the circumstances and the 
corrective actions to be taken. All constituents listed in Table 1 to 
this subpart shall be monitored as part of the corrective action 
program set forth in Sec.  192.54 of this part.


Sec.  192.54  Corrective action program.

    (a) A corrective action program shall be developed by the licensee 
and approved by the regulatory agency for each ISR site at the time of 
licensing. The plan shall address a range of possible excursion and 
exceedance scenarios (e.g., minor to catastrophic) and list options for 
corrective action. If an excursion is detected at a licensed facility 
at any time during the ISR operational phase or restoration phase, or 
an exceedance is detected during the stability or long-term stability 
phase, applicable portions of the corrective action program shall be 
implemented as soon as is practicable, and in no event later than 
ninety (90) days after such an occurrence. With the objective of 
returning constituent concentration levels in groundwater to the 
restoration goals within the production zone and the maximum 
contaminant level in adjacent aquifers, the corrective action program 
shall:
    (1) Address removing constituents at the point of compliance or 
treating them in place; and
    (2) Address removing or treating in place any constituents that 
exceed groundwater protection standards between the point of compliance 
and the point of exposure.
    (b) The licensee shall continue corrective action measures to the 
extent necessary to achieve and maintain compliance with the 
groundwater protection standards in Sec.  192.52(c) of this subpart. 
The regulatory agency will determine when the licensee may terminate 
corrective action measures based on data from the groundwater 
monitoring program and other information that provides reasonable 
assurance that the groundwater protection standards in Sec.  192.52(c) 
will not be exceeded.
    (c) After the corrective action program has been terminated, the 
licensee must establish and implement a groundwater monitoring program 
to demonstrate the effectiveness of the corrective action program in 
stabilizing the concentrations of constituents in the groundwater. The 
monitoring program shall continue for a period of not less than 3 years 
and be based on the requirements specified in Sec.  192.53(d) and 
192.53(e).


Sec.  192.55  Effective date.

    Subpart F shall be effective on [60 DAYS AFTER DATE OF PUBLICATION 
OF FINAL RULE IN FEDERAL REGISTER].

[FR Doc. 2015-00276 Filed 1-23-15; 8:45 am]
BILLING CODE 6560-50-P


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