[Federal Register Volume 91, Number 76 (Tuesday, April 21, 2026)]
[Notices]
[Pages 21335-21337]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-07700]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-7513; NRC-2021-0193]
Kairos Power LLC; Hermes Test Reactor; Environmental Assessment
and Finding of No Significant Impact
AGENCY: Nuclear Regulatory Commission.
ACTION: Notice; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC or the Commission)
is issuing an environmental assessment (EA) and finding of no
significant impact (FONSI) regarding the Kairos Power LLC (Kairos or
the licensee) request to amend Construction Permit No. CPTR-6 for the
Hermes test reactor facility in Oak Ridge, Tennessee. The amendment
request seeks NRC approval to extend the latest date for completion of
the construction of the Hermes test reactor facility from December 31,
2026, to April 30, 2029.
DATES: The EA and FONSI referenced in this document are available on
April 21, 2026.
ADDRESSES: Please refer to Docket ID NRC-2021-0193 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-2021-0193. Address
questions about Docket IDs in Regulations.gov to Bridget Curran;
telephone: 301-415-1003; email: [email protected]. For technical
questions, contact the individual(s) 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 ADAMS Public 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] 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: Cayetano Santos Jr., Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-7270; email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Introduction
The NRC is considering issuance of an amendment to Construction
Permit No. CPTR-6, issued to Kairos for the construction of the Hermes
test reactor facility in Oak Ridge, Tennessee. Kairos requested the
amendment by letter dated March 24, 2026, in accordance with section
50.90 of title 10 of the Code of Federal Regulations (10 CFR),
``Application for amendment of license, construction permit, or early
site permit,'' and 10 CFR 50.55(b). The amendment would extend the
latest date for completion of the construction of the Hermes test
reactor facility from December 31, 2026, to April 30, 2029.
In accordance with 10 CFR 51.21, ``Criteria for and identification
of licensing and regulatory actions requiring environmental
assessments,'' the NRC prepared an EA, pursuant to 10 CFR 51.30,
``Environmental assessment,'' that analyzes the environmental impacts
of the proposed amendment and alternatives, as appropriate. Based on
the results of this EA, which is set forth in section II of this
document, and in accordance with 10 CFR 51.31(a), the NRC has
determined not to prepare an environmental impact statement for the
proposed amendment and is issuing a FONSI, which is set forth in
section III of this document.
II. Environmental Assessment
Description of the Proposed Action
The proposed action would amend Construction Permit No. CPTR-6 to
extend the latest date for completion of the construction of the Hermes
test reactor facility from December 31, 2026, to April 30, 2029. The
proposed action was requested in the licensee's application dated March
24, 2026.
The proposed action would not allow any work to be performed that
is not already authorized by the construction permit. The proposed
action would grant Kairos more time to complete the construction of the
Hermes test reactor facility in accordance with the construction
permit.
Need for the Proposed Action
Kairos performed a review of the Hermes test reactor facility
construction schedule and determined that construction will not be
completed by December 31, 2026, the latest date for completion of
construction prescribed in Construction Permit No. CPTR-6. Kairos
stated that delays have occurred due to two factors. First, Kairos
stated in its amendment request that it has performed non-nuclear
demonstrations of first-of-a-kind construction techniques and design
features prior to performing them on the Hermes nuclear facility for
the purpose of identifying construction challenges and lessons learned
in the construction processes for the Hermes test reactor facility.
Kairos further stated that performing these non-nuclear demonstration
activities has extended the construction timeline. Second, Kairos
stated that site preparation work, including removal of legacy
structures from the Hermes test reactor footprint, required extensive
coordination with other organizations such as the Department of Energy
and required significantly more work than originally planned. Kairos
now expects the construction of the Hermes test reactor facility to be
completed in 2028. To accommodate this construction schedule and to
incorporate conservatism, Kairos is requesting to extend the latest
date for completion of the construction of the Hermes test reactor
facility to April 30, 2029.
The NRC regulation in 10 CFR 50.55(b) states that upon good cause
shown, the Commission will extend the completion date for a reasonable
period of time and that the Commission will recognize, among other
things, ``developmental problems attributable to the experimental
nature of the facility or
[[Page 21336]]
fire, flood, explosion, strike, sabotage, domestic violence, enemy
action, an act of the elements, and other acts beyond the control of
the permit holder,'' as a basis for extending the completion date.
Environmental Impacts of the Proposed Action
The NRC has completed its environmental review of the proposed
action and concludes that there are no significant environmental
impacts associated with the proposed action.
The proposed action would only extend the period of construction
activities already authorized by Construction Permit No. CPTR-6 and
would not authorize any new construction activities, any additional
land disturbance, or any modifications to the facility from the terms
in the construction permit.
In 2023, the NRC evaluated the environmental impacts associated
with constructing, operating, and decommissioning the Hermes test
reactor facility in NUREG-2263, ``Environmental Impact Statement for
the Construction Permit for the Kairos Hermes Test Reactor Final
Report.'' NUREG-2263 concluded that the potential impacts from the
facility would be small for each potentially affected environmental
resource.
In May 2025, Kairos commenced safety-related construction
activities at the Hermes test reactor site in Oak Ridge, Tennessee.
Kairos has completed construction of the foundation drilled piers and
is making progress in the design and construction of the facility.
Since the proposed action would only extend the period of already-
authorized construction activities, it does not involve any different
impacts or significant changes to those impacts described and analyzed
in the previous environmental documents. Therefore, there would be no
significant non-radiological or radiological environmental impacts
associated with the proposed action. Specifically:
The proposed action would not result in a change in the
types or quantity of radioactive materials in effluents, wastes, and
products of the facility. Therefore, there is no impact on occupational
or public radiation exposure and the proposed action would not result
in changes to radiological human health previously assessed in NUREG-
2263.
The proposed action would not result in new land
disturbance or in changes to land use and visual resources from what
was previously assessed in NUREG-2263.
The proposed action would not result in changes to the
types or quantity of non-radiological waste and effluents previously
assessed in NUREG-2263 and the proposed action would not result in
changes to nonradiological human health previously assessed in NUREG-
2263.
The proposed action would not result in changes to
ecological resources previously assessed in NUREG-2263.
The proposed action would not result in changes to
hydrogeology or water resources previously assessed in NUREG-2263.
The proposed action would not result in changes to air
quality or noise previously assessed in NUREG-2263.
The proposed action would not result in changes to
historic or cultural resources previously assessed in NUREG-2263.
The proposed action would not result in changes to
socioeconomic conditions previously assessed in NUREG-2263.
The proposed action would not have a significant adverse
effect on the probability of an accident occurring.
Environmental Impacts of the Alternatives to the Proposed Action
As an alternative to the proposed action, the NRC staff considered
denial of the proposed action (i.e., the ``no-action'' alternative).
Denial of the amendment request would result in the licensee being
unable to complete construction and begin operation of the Hermes test
reactor facility. However, because the remaining construction,
operating, and decommissioning impacts would generally be small as
evaluated in NUREG-2263, the environmental impacts of the proposed
action and the alternative action are similar.
Alternative Use of Resources
There are no unresolved conflicts concerning alternative uses of
available resources under the proposed action. The proposed action does
not involve the use of any resources not previously considered in
NUREG-2263.
Agencies and Persons Consulted
No additional agencies or persons were consulted regarding the
environmental impact of the proposed action. The NRC staff determined
that the proposed action would have no effect on Federally listed
threatened or endangered species or critical habitat that could occur
on or near the Hermes test reactor facility site and would have no
effect on any historic properties. Therefore, consultation was not
required under section 7 of the Endangered Species Act of 1973, as
amended, or under section 106 of the National Historic Preservation Act
of 1966, as amended. On April 14, 2026, the NRC notified the Tennessee
Division of Radiological Health representative of the EA and FONSI.
III. Finding of No Significant Impact
The proposed action is the issuance of an amendment to Kairos
Construction Permit No. CPTR-6 to extend the latest date for completion
of the construction of the Hermes test reactor facility from December
31, 2026, to April 30, 2029. Consistent with 10 CFR 51.21, the NRC
prepared an EA to determine the impacts of the proposed action. On the
basis of the EA included in section II of this document and
incorporated by reference in this finding, the NRC concludes that the
proposed action would not have a significant adverse effect on the
probability of an accident occurring and would not have any significant
radiological or non-radiological impacts. Therefore, the NRC concludes
that the proposed action will not have a significant effect on the
quality of the human environment. Accordingly, the NRC has determined
not to prepare an environmental impact statement for the proposed
action, in accordance with 10 CFR 51.31(a).
Other than the application dated March 24, 2026, the related
environmental document is NUREG-2263, ``Environmental Impact Statement
for the Construction Permit for the Kairos Hermes Test Reactor Final
Report,'' which provides the latest environmental review of the
construction, operation, and decommissioning of the Hermes test reactor
facility and description of the environmental conditions at the
facility site.
This EA and FONSI and other related 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 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 through ADAMS, as indicated.
[[Page 21337]]
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Document ADAMS accession No.
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NUREG-2263, ``Environmental Impact ML23214A269.
Statement for the Construction Permit for
the Kairos Hermes Test Reactor Final
Report,'' dated August 2023.
Construction Permit No. CPTR-6 for the ML23338A258.
Hermes 1 Test Reactor Facility, dated
December 14, 2023.
Kairos Power LLC Hermes Test Reactor ML26083A275 (Package).
Construction Permit CPTR-6 Amendment
Request, dated March 24, 2026.
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Authority: 42 U.S.C. 2011 et seq.
Dated: April 16, 2026.
For the Nuclear Regulatory Commission.
Joshua Borromeo,
Chief, Advanced Reactor Licensing Branch 1, Division of Advanced
Reactors and Non-Power Production and Utilization Facilities, Office of
Nuclear Reactor Regulation.
[FR Doc. 2026-07700 Filed 4-20-26; 8:45 am]
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