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

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.51 52 53 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.
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    \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\
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    \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.
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    \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

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.59 60 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.64 65 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 10-4 (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-

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.
---------------------------------------------------------------------------

    \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.
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    \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

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.
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    \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

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

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

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

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:
     Amending Sec.  192.32 to address a ruling of the Tenth
Circuit Court of Appeals;
     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
     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).

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

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.

    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

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.

    (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

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 10-4 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 10-4, at a
point of exposure, to an average individual.

     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:

    (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