Exelon Generation Company, LLC; LaSalle County Station, Units 1 and 2, 14158-14163 [2021-05195]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 86, Number 47 (Friday, March 12, 2021)]
[Notices]
[Pages 14158-14163]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05195]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-373 and 50-374; NRC-2021-0034]


Exelon Generation Company, LLC; LaSalle County Station, Units 1 
and 2

AGENCY: Nuclear Regulatory Commission.

ACTION: Environmental assessment and finding of no significant impact; 
issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is considering 
issuance of amendments to Renewed Facility Operating License Nos. NPF-
11 and NPF-18 issued to Exelon Generation Company, LLC (Exelon, the 
licensee) for operation of LaSalle County Station, Units 1 and 2 
(LaSalle), located in Brookfield Township, LaSalle County, Illinois. 
The proposed action would revise the technical specifications (TS) for 
the plant to allow for an average, rather than absolute, ultimate heat 
sink (UHS) sediment level and would modify the UHS temperature curve to 
increase the allowable TS diurnal temperature limits of the cooling 
water supplied to the plant from the UHS. The NRC is issuing an 
environmental assessment (EA) and finding of no significant impact 
(FONSI) associated with the proposed license amendments.

DATES: The EA and FONSI referenced in this document are available on 
March 12, 2021.

ADDRESSES: Please refer to Docket ID NRC-2021-0034 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly available information related to this document 
using any of the following methods:
     Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2021-0034. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individuals listed in the FOR FURTHER 
INFORMATION CONTACT section of this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS 
Search.'' For problems with ADAMS, please contact the NRC's Public 
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or 
by email to [email protected]. For the convenience of the reader, 
the ADAMS accession numbers are provided in a table in the 
``Availability of Documents'' section of this document.
     Attention: The PDR, where you may examine and order copies 
of public documents, is currently closed. You may submit your request 
to the PDR via email at [email protected] or call 1-800-397-4209 or 
301-415-4737, between 8:00 a.m. and 4:00 p.m. (EST), Monday through 
Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Briana Grange, Office of Nuclear 
Material Safety and Safeguards, telephone: 301-415-1042; email: 
[email protected]; and Bhalchandra Vaidya, Office of Nuclear 
Reactor Regulation, telephone: 301-415-3308; email: 
[email protected]. Both are staff of the U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION:

[[Page 14159]]

I. Introduction

    The NRC is considering issuance of amendments to Renewed Facility 
Operating License Nos. NPF-11 and NPF-18 issued to Exelon for LaSalle 
located in LaSalle County, Illinois. Exelon submitted its license 
amendment request in accordance with section 50.90 of title 10 of the 
Code of Federal Regulation (10 CFR), by letter dated July 17, 2020, as 
supplemented by letters dated September 11, 2020, and October 22, 2020.
    In accordance with 10 CFR 51.21, the NRC staff prepared the 
following EA that analyzes the environmental impacts of the proposed 
licensing action. Based on the results of this EA, the NRC staff did 
not identify any significant environmental impacts associated with the 
proposed amendments and the NRC staff is, therefore, issuing a FONSI in 
accordance with 10 CFR 51.32.

II. Environmental Assessment

Plant Site and Environs

    LaSalle is a two-unit nuclear power plant located in Brookfield 
Township in LaSalle County, Illinois, approximately 75 miles (mi) (120 
kilometers (km)) southwest of downtown Chicago, Illinois. The LaSalle 
site lies in a rural area predominantly used for agriculture and wind-
power generation. An onsite 2,058 acre (ac) (833-hectare (ha)) cooling 
pond provides condenser cooling. Cooling water that is not otherwise 
lost from the pond through evaporation or seepage is recirculated from 
the cooling pond through the condenser systems in a continuous loop. 
Underground pipelines approximately 3.5 mi (5.6 km) long connect the 
cooling pond to the Illinois River, which is the source of the plant's 
makeup water and the receiving body of water for plant blowdown. A 
small screen house located on the river provides makeup water to the 
cooling pond, and a portion of the water in the cooling pond is 
discharged as blowdown to the river on a near continuous basis.
    A dedicated portion of the cooling pond located immediately 
adjacent to the LaSalle intake canal serves as the plant's UHS. The UHS 
is also known as the core standby cooling system (CSCS) pond, and it 
directly supplies water to the CSCS cooling water system equipment. The 
UHS provides a heat sink for process and operating heat from safety-
related components during the UHS design basis event. The UHS design 
basis event includes a failure of the cooling pond dike. In such an 
event, the UHS would become the remaining source of cooling water to 
plant safety systems. In such an event, the UHS allows for the safe 
shutdown and cooldown of both LaSalle units for a 30-day period with no 
additional makeup water source. The UHS also provides a source of 
emergency makeup water for the spent fuel pools and can provide water 
for fire protection equipment.
    The cooling pond is a wastewater treatment works as defined by 
Section 301.415 of Title 35 of the Illinois Administrative Code (35 IAC 
301.415). Under this definition, the cooling pond is not considered 
waters of the State under Illinois Administrative Code (35 IAC 301.440) 
or waters of the United States under the Federal Clean Water Act (40 
CFR 230.3(s)), and so the cooling pond is not subject to Federal or 
State water quality standards.
    Exelon leases a large portion of the cooling pond to the Illinois 
Department of Natural Resources (IDNR), which maintains the leased 
portion of the pond as an outdoor recreation area for public use and 
fishing. IDNR has actively managed fish populations in the cooling pond 
since 1984. The cooling pond can be characterized as a highly managed 
ecosystem in which IDNR fish stocking and other human activities 
primarily influence the species composition and population dynamics. 
IDNR surveys the cooling pond each year and determines which fish to 
stock based on fishermen preferences, fish abundance, different 
species' tolerance to warm waters, predator and prey dynamics, and 
other factors. Currently, commonly stocked species include largemouth 
bass (Micropterus salmoides), smallmouth bass (M. dolomieu), black 
crappie (Pomoxis nigromaculatus), white crappie (P. annularis), channel 
catfish (Ictalurus punctatus), blue catfish (I. furcatus), striped bass 
hybrid (Morone saxatilis x M. chrysops), walleye (Sander vitreus), and 
bluegill (Lepomis macrochirus). Because cooling pond temperatures are 
high in the summer months, the introductions of warm-water species, 
such as largemouth bass and blue catfish, has been more successful than 
the introductions of cool-water species, such as walleye and 
muskellunge (Esox masquinongy). In addition to the stocked species, 
gizzard shad (Dorosoma cepedianum) and threadfin shad (D. petenense) 
also occur in the cooling pond. Shad are not recreationally fished, and 
IDNR does not currently stock these fish. IDNR stocks some 
recreationally fished species that consume shad (e.g., catfish and 
striped bass) in part to limit the size of shad populations.
    The plant site and environs are described in greater detail in 
Chapter 3 of the NRC's August 2016, ``Generic Environmental Impact 
Statement for License Renewal of Nuclear Plants: Regarding LaSalle 
County Station, Units 1 and 2, Final Report'' (NUREG-1437, Supplement 
57; (herein referred to as the ``LaSalle FSEIS'' [Final Supplemental 
Environment Impact Statement]). Figures 3-3 and 3-4 on pages 3-4 and 3-
5 of the LaSalle FSEIS, respectively, depict the plant layout. Figure 
3-6 on page 3-9 depicts the cooling pond, including the portion of the 
pond that constitutes the UHS, as well as the blowdown line to the 
Illinois River.

Description of the Proposed Action

    If approved, the proposed action would revise TS Surveillance 
Requirement (SR) 3.7.3.2 concerning the UHS sediment level verification 
requirement to allow for an average, rather than absolute, sediment 
level. The proposed action would also modify the temperature curve 
associated with TS SR 3.7.3.1 to increase the allowable TS diurnal 
temperature limits of the cooling water supplied to the plant from the 
UHS. Other conforming TS changes would also be made.
    Specifically, the proposed action would modify TS SR 3.7.3.2. This 
TS currently requires Exelon to verify that the sediment level in the 
intake flume and CSCS pond is less than or equal to (<=) 1.5 feet (ft) 
(18 inches (in.) or 0.5 meters (m)). This TS would be modified to allow 
an average, rather than absolute, sediment level. The revised 
requirement would state, ``Verify average sediment level is 6 inches in 
the intake flume and the CSCS pond.''
    The proposed action would also modify the temperature curve 
associated with TS SR 3.7.3.1. This requirement currently states, 
``Verify cooling water temperature supplied to the plant from the CSCS 
pond is within the limits of Figure 3.7.3-1.'' Under the proposed 
action, Figure 3.7.3-1 would be modified to specify new diurnal 
temperature limits. The revised TS temperature limits would continue to 
vary with the diurnal cycle and would continue to limit the maximum 
temperature of the UHS supplied to plant safety systems to below 107 
degrees Fahrenheit ([deg]F) (41.7 degrees Celsius ([deg]C)), the design 
limit of the plant. The revised limits would increase the allowable 
maximum UHS temperature of cooling water by 1.54 to 3.54 [deg]F (0.85 
to 1.97 [deg]C) as compared to current limits and depending on time of 
day. Table 1 lists the current and proposed temperature limits, and 
Figure 1 depicts these limits graphically.
    Additionally, the proposed action would make conforming changes to 
the LaSalle TS as described in the licensee's

[[Page 14160]]

application dated July 17, 2020, as supplemented by letters dated 
September 11, 2020, and October 22, 2020. The proposed action would be 
in accordance with the licensee's application.

                              Table 1--Current and Proposed UHS Temperature Limits
----------------------------------------------------------------------------------------------------------------
                                                                                                     TS limit
                         Time of day                              Current TS      Proposed TS       difference
                                                                limit ([deg]F)   limit ([deg]F)      ([deg]F)
----------------------------------------------------------------------------------------------------------------
0:00.........................................................           103.78           105.32             1.54
3:00.........................................................           101.97           104.18             2.21
6:00.........................................................           101.25           104.79             3.54
9:00.........................................................           102.44           104.77             2.33
12:00........................................................           104.00           105.76             1.76
15:00........................................................           104.00           106.00             2.00
18:00........................................................           104.00           106.00             2.00
21:00........................................................           104.00           106.00             2.00
24:00........................................................           103.78           105.32             1.54
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                                                                                                 [GRAPHIC] [TIFF OMITTED] TN12MR21.011
                                                                                                 
Need for the Proposed Action

    The licensee has requested the proposed amendments in connection 
with recent meteorological and atmospheric conditions that have 
resulted in challenges to the TS UHS temperature. These conditions 
include elevated air temperatures, high humidity, and low wind speed. 
The proposed action would provide the licensee with operational 
flexibility during periods of high UHS temperatures in order to prevent 
plant shutdown.

Environmental Impacts of the Proposed Action

    With regard to radiological impacts, the proposed action would not 
result in any changes in the types of radioactive effluents that may be 
released from the plant offsite. No significant increase in the amount 
of any radioactive effluent released offsite or significant increase in 
occupational or public radiation exposure is expected from the proposed 
action. Separate from this EA, the NRC staff is evaluating the 
licensee's safety analyses of an accident that may result from the 
proposed action. The results of the NRC staff's evaluation will be 
documented in a safety evaluation (SE). If the NRC staff concludes in 
the SE that all pertinent regulatory requirements are met by the 
proposed amendments, then

[[Page 14161]]

the proposed action would result in no significant radiological impact 
to the environment. The NRC staff's SE will be issued with the license 
amendments, if approved by the NRC.
    With regard to potential non-radiological impacts, raising the 
maximum allowable UHS diurnal temperature limits could cause the UHS 
portion of the cooling pond to experience increased water temperatures. 
Because the proposed action would not affect LaSalle's licensed thermal 
power level, the temperature rise across the condensers as cooling 
water travels through the cooling system would remain constant. Thus, 
if water in the UHS were to rise to the proposed allowable limits 
according to the proposed temperature curve, heated water returning to 
the cooling pond would also experience a corresponding 1.54 to 3.54 
[deg]F (0.85 to 1.97 [deg]C) increase compared to current limits and 
depending on time of day. That additional heat load would dissipate 
across some thermal gradient as discharged water mixes within the 
cooling pond.
    Many freshwater fish, such as those species that inhabit the 
cooling pond, experience thermal stress and can die when they encounter 
water temperatures at or above 95 [deg]F (35 [deg]C). Fish kills tend 
to occur when water temperatures rise above this level for some 
prolonged period of time and fish are unable to tolerate the higher 
temperatures or cannot retreat into cooler waters. Fish that experience 
thermal effects within the region of the cooling pond that is thermally 
affected by LaSalle's effluent discharge (e.g., the discharge canal, 
the flow path between the discharge canal and UHS, and the UHS itself) 
are experiencing effects that are, at least in part, attributable to 
plant operation.
    Under current operating conditions, LaSalle's cooling pond 
occasionally experiences fish kills. Such events only occur in the 
summer months and tend to be correlated with periods of high ambient 
air temperatures, low winds, and high humidity. Appendix B, Section 4.1 
of the LaSalle renewed facility operating licenses requires Exelon to 
report fish kills to the NRC as unusual or important environmental 
events if they are causally related to plant operation. Since 2001, 
Exelon has reported four fish kill events. The events occurred in July 
2001, June 2005, June 2009, August 2010, and primarily affected gizzard 
shad. The IDNR identified other dead fish to include carp (Cyprinus 
carpio), smallmouth buffalo (Ictiobus bubalus), freshwater drum 
(Aplodinotus grunniens), channel catfish, striped bass hybrid, 
smallmouth bass, walleye, bluegill, white bass (Morone chrysops), 
yellow bullhead catfish (Ameiurus natalis), and yellow bass (M. 
mississippiensis). The temperature in the cooling pond during these 
events ranged from 93 [deg]F (33.9 [deg]C) to 101 [deg]F (38.3 [deg]C), 
and each event resulted in the death of approximately 1,500 to 94,500 
fish. During the largest of these events, which was in July 2001, the 
IDNR found the maximum temperature in the cooling pond discharge canal 
to be 120 [deg]F (48.9 [deg]C) and dissolved oxygen levels to range 
from 6.2 to 18.8 parts per million. Section 3.7.2.2 of the LaSalle 
FSEIS describes these events in more detail. Since the NRC issued the 
FSEIS in 2016, Exelon has not reported any more recent fish kill events 
to the NRC. However, Exelon has observed several smaller non-reportable 
fish kills in the cooling pond since that time. Exelon attributes these 
non-reportable events to a combination of high-water temperatures, low 
winds, and high humidity. The most recent non-reportable fish kill 
occurred in July 2020.
    In Section 4.7.1.3 of the LaSalle FSEIS, the NRC staff concluded 
that thermal impacts associated with continued operation of LaSalle 
during the license renewal term would be small for all aquatic 
resources in the cooling pond except for gizzard shad and threadfin 
shad, which would experience moderate thermal impacts. Moderate impacts 
are environmental effects that are sufficient to alter noticeably, but 
not destabilize, important attributes of the resource. The NRC staff 
determined that fish kills would have noticeable impacts on important 
attributes of the aquatic environment within the cooling pond (i.e., 
shad) based on the following:
     Exelon and IDNR noted reductions in shad population sizes 
following fish kills in the cooling pond.
     Exelon and IDNR attributed the decline in shad populations 
to fish kills causally related to plant operation.
     Based on the definition of important species in the NRC's 
Standard Review Plans for Environmental Reviews for Nuclear Power 
Plants, Supplement 1: Operating License Renewal, Revision 1 (NUREG-
1555, Supplement 1, Revision 1, shad is an important aquatic attribute 
to the cooling pond ecosystem because it is prey for many 
recreationally important species.
     Fish kills are not destabilizing to shad populations 
because they tend to recover in about a year.
     Fish kills are expected to continue to occur in the 
cooling pond during the license renewal term.
    For all other aquatic species, including recreationally important 
fish stocked by the IDNR, the NRC staff concluded in the FSEIS that 
thermal effects during the license renewal term would be small. Stocked 
species are a minor portion of affected fish during most fish kills, 
and the NRC staff found no evidence that fish kills noticeably altered 
populations of stocked species. Additionally, the staff noted that if a 
future fish kill negatively impacts a stocked species, the IDNR could 
mitigate such an effect by increasing the stocking level of that 
species during the following spring. At the time the NRC staff 
performed its license renewal review, the UHS TS temperature limits 
were the same as the current limits (see Table 1 and Figure 1).
    The NRC staff anticipates that thermal effects under the proposed 
action would be qualitatively similar to those described in the FSEIS. 
The primary difference under the proposed action would be an 
incremental increase in the likelihood in the summer that fish in the 
thermally affected portion of the cooling pond would experience thermal 
effects causally related to plant operation. This is because under the 
proposed action, Exelon could continue to operate LaSalle during 
periods of higher UHS temperatures when it would currently be required 
to shut down. However, because the UHS is a small portion of the 
cooling pond, the majority of the cooling pond would be unaffected by 
the proposed action, and fish would be able to seek refuge in those 
cooler areas. Therefore, only fish within the region of the cooling 
pond that is thermally affected by LaSalle's effluent discharge (e.g., 
the discharge canal, the flow path between the discharge canal and UHS, 
and the UHS itself) at the time of elevated temperatures would likely 
be affected. Thermal effects would be most intense in or near the 
discharge canal and would decrease across a thermal gradient extending 
from the discharge canal.
    As described previously in this EA, the fish species most likely to 
experience thermal effects in the cooling pond are threadfin shad and 
gizzard shad. These species are the most likely to die from thermal 
stress. However, shad populations generally recover quickly, and shad 
are consistently the most abundant species in the cooling pond. Thus, 
fish kills and other thermal effects do not appear to significantly 
influence these species' populations. Stocked species generally 
constitute a small portion of fish affected by fish

[[Page 14162]]

kills, and these species would continue to be assessed and stocked by 
the IDNR on an annual basis in accordance with the lease agreement 
between Exelon and IDNR. Continued stocking would mitigate any minor 
effects resulting from the proposed action.
    In addition to the increase in allowable TS diurnal temperature 
limits, the proposed action would revise the TS to allow for an 
average, rather than absolute, UHS sediment level. This TS relates to 
ensuring an adequate volume of cooling water is available. This change 
would have no adverse effect on aquatic resources.
    Based on the foregoing analysis, the NRC staff concludes that the 
proposed action would not result in significant impacts to aquatic 
resources in the cooling pond.
    Some terrestrial species, such as birds or other wildlife, rely on 
fish or other aquatic resources from the cooling pond as a source of 
food. The NRC staff does not expect any significant impacts to birds or 
other wildlife because, if a fish kill occurs, the number of dead fish 
would be a small proportion of the total population of fish in the 
cooling pond. Furthermore, during fish kills, birds and other wildlife 
could consume many of the floating, dead fish.
    With respect to water resources and ecological resources along and 
within the Illinois River, the Illinois Environmental Protection Agency 
(IEPA) imposes regulatory controls on LaSalle's thermal effluent 
through Title 35, Environmental Protection, Section 302, ``Water 
Quality Standards,'' of the Illinois Administrative Code (35 IAC 302) 
and through the National Pollutant Discharge Elimination System (NPDES) 
permitting process pursuant to the Clean Water Act. Section 302 of the 
Illinois Administrative Code stipulates that ``[t]he maximum 
temperature rise shall not exceed 2.8 [deg]C (5 [deg]F) above natural 
receiving water body temperatures,'' (35 IAC 302.211(d)) and that 
``[w]ater temperature at representative locations in the main river 
shall at no time exceed 33.7 [deg]C (93 [deg]F) from April through 
November and 17.7 [deg]C (63 [deg]F) in other months'' (35 IAC 
302.211(e)). Additional stipulations pertaining to the mixing zone 
further protect water resources and biota from thermal effluents. The 
LaSalle NPDES permit contains special conditions that mirror these 
temperature requirements and that stipulate more detailed temperature 
requirements at the edge of the mixing zone. Under the proposed action, 
LaSalle's thermal effluent would continue to be limited by the Illinois 
Administrative Code and the LaSalle NPDES permit to ensure that LaSalle 
operations do not create adverse effects on water resources or 
ecological resources along or within the Illinois River. Occasionally, 
Exelon has applied for a provisional variance to allow higher-than-
permitted temperatures at the edge of the discharge mixing zone. For 
instance, Exelon applied for and the IEPA granted provisional variances 
in March, July, and August 2012, during unusual weather conditions and 
associated high ambient river water temperatures that impacted the 
ability for LaSalle's thermal discharges to meet the requirements of 
its NPDES permit. Exelon reported no fish kills or other events to the 
IEPA or the NRC that would indicate adverse environmental effects 
resulting from the provisional variance. The details of this 
provisional variance are described in Section 3.5.1.3 of the LaSalle 
FSEIS.
    Under the proposed action, Exelon would remain subject to these 
Federal and State regulatory controls. The NRC staff finds it 
reasonable to assume that Exelon's continued compliance with, and the 
State's continued enforcement of, the Illinois Administrative Code and 
the LaSalle NPDES permit would ensure that Illinois River water and 
ecological resources are protected. Further, the proposed action would 
not alter the types or amount of effluents being discharged to the 
river as blowdown. Therefore, the NRC staff does not expect any 
significant impacts to water resources or ecological resources within 
and along the Illinois River as a result of the proposed action.
    With respect to federally listed species, the NRC staff considered 
federally listed species and designated critical habitats protected 
under the Endangered Species Act (ESA) during its license renewal 
environmental review for LaSalle. Based on its review of aquatic 
surveys conducted in the cooling pond and Illinois River both upstream 
and downstream of LaSalle, the NRC staff found that no federally listed 
species had the potential to occur in areas that would be directly or 
indirectly affected by license renewal (i.e., the action area). The NRC 
staff also confirmed that no designated critical habitats occurred in 
the action area. Accordingly, the NRC staff concluded that continued 
operation of LaSalle during the license renewal term would have no 
effect on federally listed species or designated critical habitats.
    As previously described, impacts of the proposed action would be 
confined to the cooling pond and would not affect water resources or 
ecological resources along and within the Illinois River. The NRC 
staff's previous ESA section 7 review determined that no federally 
listed aquatic species or designated critical habitats occur within or 
near the cooling pond. The NRC staff has not identified any information 
indicating the presence of federally listed species in the area since 
that consultation concluded, and the U.S. Fish and Wildlife Service 
(FWS) has not listed any new aquatic species that may occur in the area 
since that time. The proposed action would not result in any 
disturbance or other impacts to terrestrial habitats, and thus, no 
federally listed terrestrial species would be affected. Accordingly, 
the NRC staff concludes that the proposed action would have no effect 
on federally listed species or designated critical habitats. 
Consultation with the FWS for the proposed action is not necessary 
because Federal agencies are not required to consult with the FWS if 
the agency determines that an action will have no effect on listed 
species or critical habitat.
    The NRC staff has identified no foreseeable land use, visual 
resource, noise, or waste management impacts given that the proposed 
action would not result in any physical changes to LaSalle facilities 
or equipment or changes to any land uses on or off site. The NRC staff 
has identified no air quality impacts given that the proposed action 
would not result in air emissions beyond what would be experienced 
during current operations. Additionally, there would be no 
socioeconomic, environmental justice, or historic and cultural resource 
impacts associated with the proposed action since no physical changes 
would occur beyond the site boundaries and any impacts would be limited 
to the cooling pond.
    Based on the foregoing analysis, the NRC staff concludes that the 
proposed action would have no significant environmental impacts.

Environmental Impacts of the Alternatives to the Proposed Action

    As an alternative to the proposed action, the NRC staff considered 
the denial of the proposed action (i.e., the ``no-action'' 
alternative). Denial of the license amendment request would result in 
no changes to the current TS. Thus, under the no-action alternative, 
the licensee would continue to be required to verify that the cooling 
water temperature supplied to the plant from the CSCS pond is within 
the limits of the current TS Figure 3.7.3-1 and that the absolute 
sediment level in the intake flume and CSCS pond is <=1.5 ft (18 in. or 
0.5 m). If these conditions are not met, the licensee would be required 
to begin shutdown of LaSalle. The no-action alternative would result in 
no

[[Page 14163]]

change in current environmental conditions or impacts at LaSalle. 
Denial of the LAR, however, could result in reduced operational 
flexibility and could require Exelon to derate or shutdown LaSalle if 
the UHS temperature approaches or exceeds the current TS temperature 
limit. Shutdown of operations at LaSalle due to an inability to meet 
current UHS temperature limit could result in various impacts, 
including loss of the energy and economic benefits that arise from 
plant operation.

Alternative Use of Resources

    There are no unresolved conflicts concerning alternative uses of 
available resources under the proposed action.

Agencies and Persons Consulted

    No additional agencies or persons were consulted regarding the 
environmental impact of the proposed action. However, in accordance 
with 10 CFR 50.91(b), the licensee provided copies of its application 
to the State of Illinois.

III. Finding of No Significant Impact

    The NRC is considering issuing amendments for Renewed Facility 
Operating License Nos. NPF-11 and NPF-18, issued to Exelon for 
operation of LaSalle that would revise the TS for the plant to allow 
for an average, rather than absolute, UHS sediment level and would 
modify the UHS temperature curve to increase the allowable TS diurnal 
temperature limits of the cooling water supplied to the plant from the 
UHS.
    Based on the EA included in Section II in this notice and 
incorporated by reference in this finding, the NRC staff concludes that 
the proposed action would not have significant effects on the quality 
of the human environment. The NRC staff's evaluation considered 
information provided in the licensee's application as well as the NRC 
staff's independent review of other relevant environmental documents. 
Section IV in this notice lists the environmental documents related to 
the proposed action and includes information on the availability of 
these documents. Based on its finding, the NRC staff has decided not to 
prepare an environmental impact statement for the proposed action.
    This FONSI and other related environmental documents are accessible 
online in the ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. Persons who do not have access to ADAMS or who 
encounter problems in accessing the documents located in ADAMS should 
contact the NRC's PDR reference staff by telephone at 1-800-397-4209 or 
301-415-4737, or by email to [email protected].

IV. Availability of Documents

    The documents identified in the following table are available to 
interested persons in ADAMS, as indicated.

------------------------------------------------------------------------
             Document description                 ADAMS accession No.
------------------------------------------------------------------------
License Amendment Request:
    Exelon Generation Company, LLC. Request    ML20204A775
     for a License Amendment to LaSalle
     County Station, Units 1 and 2, Technical
     Specification 3.7.3, ``Ultimate Heat
     Sink,'' dated July 17, 2020.
    Exelon Generation Company, LLC. Licensee   ML20259A454
     Response to the NRC requirement for
     Supplemental Information regarding the
     request for a License Amendment to
     LaSalle County Station, Units 1 and 2,
     Technical Specification 3.7.3,
     ``Ultimate Heat Sink,'' dated September
     11, 2020.
    Exelon Generation Company, LLC. Revised    ML20296A456
     Licensee Response to the NRC requirement
     for Supplemental Information regarding
     the request for a License Amendment to
     LaSalle County Station, Units 1 and 2,
     Technical Specification 3.7.3,
     ``Ultimate Heat Sink,'' dated October
     22, 2020.
Other Referenced Documents:
    U.S. Fish and Wildlife Service.            ML16120A505
     Endangered Species Consultations:
     Frequently Asked Questions, dated July
     15, 2013.
    U.S. Nuclear Regulatory Commission.        ML13106A246
     Standard Review Plans for Environmental
     Reviews for Nuclear Power Plants,
     Supplement 1: Operating License Renewal,
     Revision 1 (NUREG[dash]1555, Supplement
     1, Revision 1, dated June 30, 2013.
    U.S. Nuclear Regulatory Commission.        ML16238A029
     Generic Environmental Impact Statement
     for License Renewal of Nuclear Plants:
     Regarding LaSalle County Station, Units
     1 and 2, Final Report (NUREG-1437,
     Supplement 57), dated August 31, 2016.
    U.S. Nuclear Regulatory Commission.        ML052990324
     Exelon Generation Company, LLC; Docket
     No. STN 50-373; LaSalle County Station,
     Unit 1 Renewed Facility Operating
     License, issued on October 19, 2016.
    U.S. Nuclear Regulatory Commission.        ML052990387
     Exelon Generation Company, LLC; Docket
     No. STN 50-374; LaSalle County Station,
     Unit 2 Renewed Facility Operating
     License, issued on October 19, 2016.
------------------------------------------------------------------------


    Dated: March 9, 2021.

    For the Nuclear Regulatory Commission.
Bhalchandra K. Vaidya,
Project Manager, Plant Licensing Branch III, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.
[FR Doc. 2021-05195 Filed 3-11-21; 8:45 am]
BILLING CODE 7590-01-P