[Federal Register Volume 90, Number 93 (Thursday, May 15, 2025)]
[Notices]
[Pages 20692-20695]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-08628]
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
[Docket No. 50-613; NRC-2024-0078]
US SFR Owner, LLC; Kemmerer Power Station, Unit 1; Exemption
AGENCY: Nuclear Regulatory Commission.
ACTION: Notice; issuance.
-----------------------------------------------------------------------
SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) staff has issued
an exemption in response to a February 28, 2025 request, as
supplemented by letters dated April 7, and April 29, 2025, from
TerraPower, LLC (TerraPower), on behalf of its wholly-owned subsidiary
US SFR Owner, LLC (USO), for the proposed Kemmerer Power Station, Unit
1 (Kemmerer 1). Specifically, TerraPower, on behalf of USO, requested
an exemption that would modify a portion of the definition of
construction applicable to the prohibition of construction of
production and utilization facilities without an NRC license for the
proposed Kemmerer 1. This exemption modifies the definition for the
proposed Kemmerer 1 and allows the driving of piles, subsurface
preparation, placement of backfill, concrete, or permanent retaining
walls within an excavation, installation of foundations, or the in-
place assembly, erection, fabrication or testing, which are for
structures, systems, and components classified as non-safety-related
with no special treatment (NST); the failure of which could cause a
reactor scram or actuation of a safety-related system that is located
on the proposed energy island prior to receipt of a construction permit
and without a limited work authorization.
DATES: The exemption was issued on May 7, 2025.
ADDRESSES: Please refer to Docket ID NRC-2024-0078 when contacting the
NRC staff 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-2024-0078. Address
questions about Docket IDs in Regulations.gov to Bridget Curran;
telephone: 301-415-1003; 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, at 301-415-4737,
or by email to [email protected]. For the convenience of the reader,
instructions about obtaining materials referenced in this document are
provided in the ``Availability of Documents'' section.
NRC's PDR: The PDR, where you may examine and order copies
of publicly available documents, is open by appointment. To make an
appointment to visit the PDR, please send an email to
[email protected]
[[Page 20693]]
or call 1-800-397-4209 or 301-415-4737, between 8 a.m. and 4 p.m.
eastern time (ET), Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Mallecia Sutton, Office of Nuclear
Reactor Regulation; telephone: 301-415-0673; email:
[email protected] and Cayetano Santos Jr., Office of Nuclear
Reactor Regulation; telephone: 301-415-7270; email:
[email protected]. Both are staff of the U.S. Nuclear Regulatory
Commission, Washington, DC 20555-0001.
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: May 12, 2025
For the Nuclear Regulatory Commission.
Mallecia Sutton,
Senior Project Manager, Advanced Reactor Licensing Branch 1 Division of
Advanced Reactors and Non-power Production and Utilization Facilities,
Office of Nuclear Reactor Regulation.
Attachment--Exemption
NUCLEAR REGULATORY COMMISSION
Docket No. 50-613; US SFR Owner, LLC.; Kemmerer Power Station Unit 1;
Exemptions
I. Background
By letter dated March 28, 2024, TerraPower, LLC (TerraPower), on
behalf of its wholly-owned subsidiary US SFR Owner, LLC (USO),
submitted a construction permit (CP) application including a
preliminary safety analysis report (PSAR) to the NRC staff for a
reactor facility pursuant to part 50 of title 10 of the Code of
Federal Regulations (10 CFR), ``Domestic Licensing of Production and
Utilization Facilities,'' and section 103 of the Atomic Energy Act
of 1954, as amended. The proposed facility, referred to as Kemmerer
Power Station Unit 1 (Kemmerer 1), if approved, would be built in
Lincoln County, Wyoming and utilize TerraPower and General Electric-
Hitachi Natrium sodium fast reactor technology. Supplements to the
application were submitted on May 2, 2024, and May 9, 2024. On May
21, 2024, the NRC staff accepted USO's CP application for docketing
(89 FR 47997).
The licensing approach in the Kemmerer 1 CP application follows
Nuclear Energy Institute (NEI) 18-04, Revision 1, ``Risk-Informed
Performance-Based Technology Inclusive Guidance for Non-Light Water
Reactor Licensing Basis Development,'' which was endorsed by the NRC
in Regulatory Guide (RG) 1.233, ``Guidance for a Technology-
Inclusive, Risk-Informed, and Performance-Based Methodology to
inform the Licensing Basis and Content of Applications for Licenses,
Certifications, and Approvals for non-light-water Reactors.'' The
NRC staff is currently conducting a detailed review of the Kemmerer
1 CP application.
TerraPower Topical Report (TR) NATD-LIC-RPRT-0001-A, Revision 0,
``Regulatory Management of Natrium Nuclear Island and Energy Island
Design Interfaces,'' discusses TerraPower's approach to decouple the
proposed Natrium energy island (EI) and nuclear island (NI). The TR
states that the independence of operation between NI and EI systems
represents a key aspect of the Natrium design philosophy. It
includes a summary of the proposed Natrium reactor plant design,
interfaces, safety features, and basic plant transient analysis that
support the decoupling strategy. As noted in the TR, certain aspects
of the plant design, such as the thermal storage system that
insulates the NI from EI transients, are key aspects of the plant
for EI-NI independence. The TR also stated that the failure of
certain NST EI SSCs could cause a reactor scram. On September 28,
2023, the NRC staff found TR NATD-LIC-RPRT-0001-A, Revision 0
acceptable for referencing in licensing actions to the extent
specified and under the limitations and conditions delineated in the
final safety evaluation (SE) of the TR. Although the TR discussed
the possibility of requesting an exemption from 10 CFR
50.10(a)(1)(iv), in the SE approving that TR, the NRC staff stated
that it was not ``taking a position . . . on any prospective
exemption request the NRC might receive.''
By letter dated September 9, 2024, TerraPower submitted, on
behalf of USO, an exemption request for the proposed Kemmerer 1. The
requested exemptions were from the definitions of construction in
10CFR 50.10(a), ``Definitions,'' and 10CFR51.4, ``Definitions,'' and
would have excluded all non-safety-related with no special treatment
(NST) EI structures, systems, and components (SSCs) from the scope
of construction as defined in these regulations. By letter dated
February 28, 2025, TerraPower submitted, on behalf of USO, a new
request that superseded the September 9, 2024 request and requested
an exemption with a more limited scope, discussed in the following
section. The April 29, 2025 supplement to the February 28, 2025
request further limited the scope of the exemption request by
withdrawing the 10 CFR 51.4 portion of the exemption.
II. Request/Action
TerraPower's request on behalf of USO in a letter dated February
28, 2025, as supplemented by letters dated April 7, and April 29,
2025, is to modify the definition of construction in 10 CFR
50.10(a)(1)(iv) from ``SSCs whose failure could cause a reactor
scram or actuation of a safety-related system'' to ``SSCs whose
failure could cause a reactor scram or actuation of a safety-related
system, excluding Natrium EI SSCs classified as non-safety-related
with no special treatment (NST).'' This specific exemption would
allow USO to proceed with the driving of piles, subsurface
preparation, placement of backfill, concrete, or permanent retaining
walls within an excavation, installation of foundations, or the in-
place assembly, erection, fabrication, or testing of SSCs classified
as NST the failure of which could cause the reactor to scram or
actuation of a safety-related system that are located on the
proposed EI without a limited work authorization while the NRC staff
continues its review of the Kemmerer 1 CP application. Issuing this
exemption would not constitute a commitment by the NRC to issue a CP
for Kemmerer 1. USO would install the SSCs assuming the risk that
its CP application may later be denied.
III. Discussion
Pursuant to 10 CFR 50.12, ``Specific exemptions,'' the
Commission may, upon application by any interested person or upon
its own initiative, grant exemptions from the requirements of 10 CFR
part 50 when: (1) the exemptions are authorized by law, will not
present an undue risk to the health and safety of the public, and
are consistent with the common defense and security; and (2) special
circumstances are present. Section 50.12 also states that for
exemptions permitting the conduct of activities prior to the
issuance of a CP prohibited by 10 CFR 50.10, the Commission may
grant the exemption upon considering and balancing the following
factors: (1) whether conduct of the proposed activities will give
rise to a significant adverse impact on the environment and the
nature and extent of such impact, if any; (2) whether redress of any
adverse environment impact from conduct of the proposed activities
can reasonably be effected should such redress be necessary; (3)
whether conduct of the proposed activities would foreclose
subsequent adoption of alternatives; and (4) the effect of delay in
conducting such activities on the public interest, including the
power needs to be used by the proposed facility, the availability of
alternative sources, if any, to meet those needs on a timely basis
and delay costs to the applicant and to consumers.
A. Exemption Is Authorized by Law
Section 50.12 allows the NRC staff to grant exemptions from the
requirements in 10 CFR part 50 provided that certain conditions
listed therein are met. As discussed in this section of the
evaluation all of the conditions listed in 10 CFR 50.12 are met.
Further, the exemption criterion in 10 CFR 50.12(b) states that the
Commission may grant the exemption upon considering and balancing
four factors related to environmental considerations. The NRC staff
has determined that granting the proposed exemption will not result
in a violation of the Atomic Energy Act of 1954, as amended, the
National Environmental Policy Act, other applicable statutes, the
NRC's regulations, or other applicable law. Accordingly, the NRC
staff finds that the exemption is authorized by law.
B. Exemption Would Not Present an Undue Risk to Public Health and
Safety
As noted previously, TerraPower TR NATD-LIC-RPRT-0001-A
identified that the failure of certain SSCs on the EI could cause
the reactor to scram, meeting the 10 CFR 50.10(a)(1)(iv) criterion.
The NRC staff's SE agreed with that assessment. Scramming the
reactor would involve the actuation of some safety-related systems.
Therefore, those SSCs meet the criteria in 10 CFR 50.10(a)(1)(iv),
meaning the driving of piles, subsurface preparation, placement of
backfill, concrete, or permanent retaining walls within an
excavation, installation of foundations, or the in-place assembly,
erection, fabrication, or testing of those SSCs would be considered
[[Page 20694]]
construction. Per 10 CFR 50.10(c), construction of these EI SSCs
cannot begin without the issuance of a CP, an early site permit, a
combined license, or a limited work authorization. The proposed
exemption would allow USO to proceed with the driving of piles,
subsurface preparation, placement of backfill, concrete, or
permanent retaining walls within an excavation, installation of
foundations, or the in-place assembly, erection, fabrication, or
testing of SSCs classified as NST the failure of which could cause
the reactor to scram or actuation of a safety-related system that
are located on the proposed EI while the NRC staff continues its
review of the Kemmerer 1 CP application without receiving a limited
work authorization.
In its exemption request, TerraPower stated that the Natrium
design incorporates independence of operation between the SSCs of
the NI and the SSCs of the EI. The exemption request further
indicated that the Kemmerer 1 CP application describes the overall
configuration of Kemmerer 1 and the independence of the EI and the
NI. TerraPower additionally provided information in the exemption
request on the design features that enable the independence of the
NI and EI. The EI is physically separate from the NI, except for an
interface between the NI and EI provided at the sodium-salt heat
exchangers (SHXs), which transfer heat from the NI's intermediate
heat transport system (IHT) to the EI's thermal salt system (TSS).
Pages 3 and 4 of the exemption request in letter dated February 28,
2025, also summarize several other features that support the
independence of the NI and EI.
The NRC staff reviewed the design described in the exemption and
the proposed PSAR and found it to be consistent with the design
features supporting NI-EI independence discussed in NATD-LIC-RPRT-
0001-A and the associated NRC staff SE. These features include
metallic fuel, primary and intermediate heat transport systems (PHT
and IHT, respectively) that enable heat to be passively removed from
the reactor core and provide thermal inertia that insulates the
reactor core from EI transients, control and protection system
functions that enable the NI to respond independently to transients,
and a thermal salt storage system which provides thermal inertia to
insulate the core from EI transients. As discussed in the NRC
staff's SE on NATD-LIC-RPRT-0001-A, this design gives the NI ``the
capacity to effectively respond safely to transients, regardless of
whether they are initiated on the NI or EI, using only NI systems.''
NATD-LIC-RPRT-0001-A and the associated NRC staff SE also clarify
that most EI SSC failures would have no impact on the NI because of
the salt system. Failures in the salt system would be initially
observed on the NI as an increase in intermediate heat transport
system temperature. The thermal inertia provided by the IHT and PHT
is such that there is time to initiate a non-safety related reactor
runback based on conditions on the NI. The runback automatically
reduces reactor power and flow in a controlled manner, potentially
avoiding a scram. The safety margins of the reactor fuel, the
thermal inertia of the PHT, and the passive residual heat removal
mechanisms are such that scrams are benign compared to the light
water reactors that comprised the operating fleet at the time the
language in 10 CFR 50.10(a)(1)(iv) was adopted. Consequently, the
NRC staff determined that even though failure of EI SSCs could cause
a reactor scram and, in the process, certain safety-related systems
to actuate, failure of EI SSCs would not have a significant effect
on the safety of the reactor. Further, there are no NST SSCs located
on the EI the failure of which could cause a safety-related system
to actuate outside of those that would actuate as part of the event
sequence leading to a reactor scram.
As discussed in the exemption request, TerraPower used the risk-
informed and performance-based process described in NEI 18-04,
Revision 1 to classify SSCs according to their safety significance.
The result of this process is one of three safety classifications--
safety-related (SR), non-safety-related with special treatment
(NSRST), and NST. SR SSCs mitigate the consequences of design basis
events and design basis accidents that only rely on SR SSCs or
prevent the frequency of certain beyond design basis events from
increasing above certain thresholds. NSRST SSCs are those non-SR
SSCs that, among other things, are relied on to perform risk-
significant functions, make significant contributions to meeting the
cumulative risk metrics, or are relied on to perform functions
requiring special treatment for defense-in-depth. As discussed in RG
1.233, ``safety-significant SSCs include all those SSCs classified
as SR or NSRST.'' RG 1.233 further notes that the staff expects that
SSCs that ``provide essential support . . . for SR or NSRST SSCs
will be classified in a manner consistent with the higher-level
function.'' Plant SSCs that are neither SR nor NSRST are NST; as
such, NST SSCs do not perform safety- or risk-significant functions,
do not significantly contribute to integrated risk measures, are not
needed for adequate defense-in-depth, and do not provide essential
support for any other SSCs that do perform those functions.
The proposed exemption would allow the driving of piles,
subsurface preparation, placement of backfill, concrete, or
permanent retaining walls within an excavation, installation of
foundations, or the in-place assembly, erection, fabrication or
testing of SSCs classified as NST the failure of which could cause
the reactor to scram or actuation of a safety-related system that
are located on the proposed EI while the NRC staff continues its
review of the Kemmerer 1 CP application without receiving a limited
work authorization. As discussed previously, EI SSCs classified as
NST are not needed to bring the plant to a safe condition following
a plant transient, whether it occurs on the EI or NI, and failure of
these SSCs would not be expected to significantly affect the safety
of the plant. Also, NST SSCs are not safety- or risk-significant, do
not contribute significantly to integrated risk measures, are not
needed for defense-in-depth purposes, and do not provide essential
support for SR or NSRST SSCs. Additionally, the Kemmerer 1 CPA
includes SSC safety classifications that are currently under review
by the staff. Should the NRC staff identify through the review
process that the driving of piles, subsurface preparation, placement
of backfill, concrete, or permanent retaining walls within an
excavation, installation of foundations, or in-place assembly,
erection, fabrication, or testing was conducted for any SSCs that
were inappropriately classified as NST, such instances would be
referred for enforcement action. In the NRC staff's engineering
judgment, based on the proposed design of the EI as discussed
previously, any misclassified EI SSCs would likely not be considered
risk-significant and therefore would not be expected to affect this
analysis or cause a cascading effect on other SSCs' classifications.
For these reasons, the staff concluded that there is no undue
risk to public health and safety in allowing the driving of piles,
subsurface preparation, placement of backfill, concrete, or
permanent retaining walls within an excavation, installation of
foundations, or the in-place assembly, erection, fabrication or
testing of SSCs classified as NST the failure of which could cause a
reactor scram or actuation of a safety-related system that are
located on the proposed EI prior to receipt of a CP.
C. Exemption Would Be Consistent With Common Defense and Security
The request would exempt the driving of piles, subsurface
preparation, placement of backfill, concrete, or permanent retaining
walls within an excavation, installation of foundations, or in-place
assembly, erection, fabrication, or testing of SSCs classified as
NST the failure of which could cause a reactor scram or actuation of
a safety-related system that are located on the proposed EI from the
10 CFR 50.10(a)(1)(iv) definition of construction. None of these
SSCs are associated with defense or security of Kemmerer 1.
Therefore, common defense and security are not impacted by this
exemption. Consequently, this exemption is consistent with the
common defense and security.
D. Special Circumstances Are Present in the Exemptions
Special circumstances, in accordance with 10 CFR
50.12(a)(2)(iii), are present whenever ``[c]ompliance [with a
regulation] would result in undue hardship or other costs that are
significantly in excess of those contemplated when the regulation
was adopted, or that are significantly in excess of those incurred
by others similarly situated.'' Without this exemption, USO would
not be able to proceed with the driving of piles, subsurface
preparation, placement of backfill, concrete, or permanent retaining
walls within an excavation, installation of foundations, or in-place
assembly, erection, fabrication, or testing of SSCs classified as
NST that meet the criteria in 10 CFR 50.10(a)(1)(iv) and are located
on the proposed EI until the NRC staff approved a CP for Kemmerer 1,
should approval of the application be the appropriate outcome of the
NRC staff's review. In its supplement letter dated April 7, 2025,
TerraPower stated that delay of construction of EI NST SSCs within
the scope of the exemption would result in substantial schedule
delays for the Natrium
[[Page 20695]]
Demonstration Project. TerraPower further stated that a delay in the
construction of EI NST SSCs within the scope of this exemption until
the projected date for issuance of the CP would result in
substantial costs due to the resulting delays in construction and
commercial operation. Therefore, the NRC staff has determined that
special circumstances exist in this case because compliance with a
regulation would result in undue hardship.
E. Commission Consideration of Factors in 50.12(b)
For exemptions permitting the conduct of activities prior to the
issuance of a CP prohibited by 10 CFR 50.10, the Commission may
grant the exemption upon considering and balancing four factors. The
NRC staff considered the balancing factors for granting such an
exemption and its evaluation is documented in the environmental
assessment (EA) that is associated with this exemption. The staff
made a finding of no significant impact.
F. Expiration
This exemption expires upon issuance of a construction permit to
USO for Kemmerer 1.
G. Environmental Considerations
In accordance with 10 CFR 51.21, the NRC has prepared an EA that
analyzes the environmental effects of the proposed action. The NRC
staff determined that the granting of these exemptions will not have
a significant effect on the quality of the human environment. Based
on the results of the EA and in accordance with 10 CFR 51.31(a), the
NRC has prepared a finding of no significant impact for the proposed
exemption. That EA and FONSI were published in the Federal Register
on May 7, 2025 (90 FR 19322)
IV. Conclusions
Accordingly, the Commission has determined that, pursuant to 10
CFR 50.12 the exemption is authorized by law, will not present an
undue risk to the public health and safety, and is consistent with
the common defense and security. Also, special circumstances are
present. Therefore, the Commission hereby grants USO a one-time
exemption from the definition of construction in 10 CFR
50.10(a)(1)(iv) for the proposed Kemmerer 1. Issuance of this
exemption shall not be deemed to constitute a commitment to issue a
CP to USO for the proposed Kemmerer 1. In addition, per 10 CFR
50.12, during the period of this exemption, any activities conducted
shall be carried out in a manner that will minimize or reduce their
environmental impact.
The exemption is effective on May 7, 2025.
V. Availability of Documents
The documents identified in the following table are available to
interested persons through ADAMS, as indicated.
------------------------------------------------------------------------
Document description ADAMS accession No.
------------------------------------------------------------------------
Submittal of the Construction ML24088A059 (package).
Permit Application for the
Natrium Reactor Plant, Kemmerer
Power Staton Unit 1 dated March
28, 2024.
Supplement to Construction Permit ML24123A242.
Application for the Natrium
Reactor Plant, Kemmerer Power
Staton Unit 1 Regarding Agreement
between US SFR Owner, LLC and
TerraPower, LLC, dated May 2,
2024.
Supplement to Construction Permit ML24123A243.
Application for the Natrium
Reactor Plant, Kemmerer Power
Staton Unit 1 Regarding Fitness-
for-Duty and Security Clarifying
Information, dated May 2, 2024.
Supplement to Construction Permit ML24130A181.
Application for the Natrium
Reactor Plant, Kemmerer Power
Staton Unit 1 Regarding Materials
of Construction Clarifying
Information, dated May 9, 2024.
Acceptance for Docketing of ML24135A109.
Kemmerer Power Station Unit 1
Construction Permit Application
by US SFR Owner, LLC dated May
21, 2024.
Nuclear Energy Institute 18-04, ML19241A336.
Revision 1, ``Risk-Informed
Performance-Based Technology
Inclusive Guidance for Non-Light
Water Reactor Licensing Basis
Development,'' dated August 2019.
Regulatory Guide 1.233, ``Guidance ML20091L698.
for a Technology-Inclusive, Risk-
Informed, and Performance-Based
Methodology to inform the
Licensing Basis and Content of
Applications for Licenses,
Certifications, and Approvals for
non-light-water Reactors'' dated
June 2020.
TerraPower Topical Report NATD-LIC- ML24011A321.
RPRT-0001-A, Revision 0,
``Regulatory Management of
Natrium Nuclear Island and Energy
Island Design Interfaces,'' dated
January 11, 2024.
NRC Staff Safety Evaluation for ML23257A258.
TerraPower Topical Report NATD-
LIC-RPRT-0001-A, Revision 0,
``Regulatory Management of
Natrium Nuclear Island and Energy
Island Design Interfaces,'' dated
September 28, 2023.
Exemption Request Associated with ML24253A023.
Construction of the Natrium
Energy Island dated September 9,
2024.
Exemption Request and Application ML25059A093.
of Topical Report NATD-LIC-RPRT-
0001-A for Construction of the
Natrium Energy Island at Kemmerer
Unit 1 dated February 28, 2025.
Supplement to Exemption Request ML25097A132.
and Application of Topical Report
NATD-LIC-RPRT-0001-A for
Construction of the Natrium
Energy Island at Kemmerer Unit 1
dated April 7, 2025.
Withdrawal of Exemption Request ML25119A205.
from 10 CFR 51.4 Definition of
Construction for Construction of
the Natrium Energy Island at
Kemmerer Unit 1 dated April 29,
2025.
Environmental Assessment and ML25119A332.
Finding of No Significant Impact
for the Exemption Request for
Construction of the Natrium
Energy Island at Kemmerer Unit 1.
------------------------------------------------------------------------
Dated: May 7, 2025.
For the Nuclear Regulatory Commission.
Jeremy Bowen,
Director, Division of Advanced Reactors and Non-power Production and
Utilization Facilities, Office of Nuclear Reactor Regulation.
[FR Doc. 2025-08628 Filed 5-14-25; 8:45 am]
BILLING CODE 7590-01-P