[Federal Register Volume 89, Number 148 (Thursday, August 1, 2024)]
[Notices]
[Pages 62806-62811]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-16978]


-----------------------------------------------------------------------

NUCLEAR REGULATORY COMMISSION

[Docket No. 50-400; NRC-2024-0125]


Duke Energy Progress, LLC; Shearon Harris Nuclear Power Plant, 
Unit 1; Exemption

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice; issuance.

-----------------------------------------------------------------------

SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued an 
exemption in response to a February 6, 2024, request, as supplemented 
by letters dated April 3 and June 7, 2024, from Duke Energy Progress, 
LLC (the licensee). The exemption relieves the licensee from NRC 
regulations requiring specific reactor protection system cables at 
Shearon Harris Nuclear Power Plant, Unit 1, to meet certain 
requirements of the Electrical and Electronics Engineers (IEEE) 
Standard 279-1971, ``Criteria for Protection Systems for Nuclear Power 
Generating Stations.''

DATES: The exemption was issued on July 26, 2024.

ADDRESSES: Please refer to Docket ID NRC-2024-0125 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-2024-0125. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individual 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 http://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]. The ADAMS accession number for 
each document referenced in this document (if that document is 
available in ADAMS) is provided the first time that it is mentioned in 
this document.
     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: Michael Mahoney, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001; telephone: 301-415-3867; email: [email protected].

SUPPLEMENTARY INFORMATION: The text of the exemption is attached.

    Dated: July 29, 2024.


[[Page 62807]]


    For the Nuclear Regulatory Commission.
Michael Mahoney,
Project Manager, Plant Licensing Branch II-2, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.

Attachment: Exemption

Nuclear Regulatory Commission

Docket No. 50-400

Duke Energy Progress, LLC

Shearon Harris Nuclear Power Plant, Unit 1

Exemption

I. Background

    Duke Energy Progress, LLC (Duke Energy, the licensee) is the holder 
of Renewed Facility Operating License No. NPF-63, which authorizes 
operation of Shearon Harris Nuclear Power Plant, Unit 1 (Harris). The 
license provides, among other things, that the facility is subject to 
all rules, regulations, and orders of the U.S. Nuclear Regulatory 
Commission (NRC) now or hereafter in effect. The facility consists of a 
pressurized-water reactor located in Wake and Chatham Counties, North 
Carolina.

II. Request/Action

    By application dated February 6, 2024 (Agencywide Documents Access 
and Management System (ADAMS) Accession No. ML24037A284), as 
supplemented by letters dated April 3, 2024 (ML24094A105), and June 7, 
2024 (ML24159A746), Duke Energy, pursuant to Title 10 of the Code of 
Federal Regulations (10 CFR) Section 50.12, ``Specific exemptions,'' 
requested an exemption from a provision in the Institute of Electrical 
and Electronics Engineers (IEEE) Standard (std) 279-1971, ``Criteria 
for Protection Systems for Nuclear Power Generating Stations,'' that is 
required by CFR 50.55a(h)(2), ``Protection systems,'' for Harris. 
Specifically, the exemption request would remove the requirement for 
the Harris reactor protection system (RPS) cables that terminate within 
turbine control system (TCS) Cabinet G (1TCS-CAB-G) to be independent 
and physically separated in accordance with IEEE 279-1971, Section 4.6, 
``Channel Independence.'' The licensee stated that application of the 
regulation in this circumstance would not serve the underlying purpose 
of the rule and is not necessary to achieve the underlying purpose of 
the rule. The exemption request was submitted for review under the 
NRC's Risk-Informed Process for Evaluations (RIPE).

III. Discussion

    The regulations in 10 CFR 50.55a(h)(2) state:

    For nuclear power plants with construction permits issued after 
January 1, 1971, but before May 13, 1999, protection systems must 
meet the requirements in IEEE Std 279-1968, ``Proposed IEEE Criteria 
for Nuclear Power Plant Protection Systems,'' or the requirements in 
IEEE Std 279-1971, ``Criteria for Protection Systems for Nuclear 
Power Generating Stations,'' or the requirements in IEEE Std 603-
1991, ``Criteria for Safety Systems for Nuclear Power Generating 
Stations,'' and the correction sheet dated January 30, 1995. For 
nuclear power plants with construction permits issued before January 
1, 1971, protection systems must be consistent with their licensing 
basis or may meet the requirements of IEEE Std. 603-1991 and the 
correction sheet dated January 30, 1995.

    Duke Energy requested an exemption from IEEE 279-1971, Section 4.6, 
as required by 10 CFR 50.55a(h)(2), for specific RPS cables at Harris. 
Contrary to the requirements in IEEE 279-1971, Section 4.6, the safety-
related RPS cables that terminate within TCS Cabinet G are not 
independent and physically separated from the non-safety-related TCS 
cables. The licensee requested the exemption in order to maintain the 
current configuration of the TCS circuitry at Harris.
    Pursuant to 10 CFR 50.12, the NRC may, upon application by any 
interested person or upon its own initiative, grant exemptions from 
requirements of 10 CFR part 50 when: (1) the exemptions are authorized 
by law, will not present an undue risk to the public health and safety, 
and are consistent with the common defense and security, and (2) 
special circumstances, as defined in 10 CFR 50.12(a)(2), are present. 
The licensee states that the special circumstances associated with its 
exemption request are that the ``application of the regulation in this 
circumstance would not serve the underlying purpose of the rule and is 
not necessary to achieve the underlying purpose of the rule.''
    The exemption request was submitted for review under the RIPE, 
which is described in the NRC's ``Guidelines for Characterizing the 
Safety Impact of Issues,'' Revision 2 (referenced henceforth as SIC) 
(ML22088A135). The Office of Nuclear Reactor Regulation (NRR) temporary 
staff guidance (TSG) document TSG-DORL-2021-01, Revision 3 
(ML23122A014), provides the framework and guidance for the staff to 
implement the streamlined processing of exemption requests from NRC 
requirements submitted under RIPE. Use of RIPE for exemption requests 
is limited to issues for which the safety impact can be modeled using 
probabilistic risk assessment (PRA) and shown to have a minimal safety 
impact per SIC. RIPE is based on the application of pre-existing risk-
informed criteria that allows for the staff's review and disposition of 
the submittal to be streamlined and efficient.
    As described in the SIC, all the following must apply in order to 
characterize an issue as having a minimal safety impact and qualify for 
consideration under the RIPE:
     The issue contributes less than 1 x 10-\7\/year 
to core damage frequency (CDF);
     The issue contributes less than 1 x 10-\8\/year 
to large early release frequency (LERF);
     The issue has no safety impact or minimal safety impact in 
accordance with the SIC; and
     Cumulative risk is assessed based on plant-specific CDF 
and LERF. Cumulative risk is acceptable for the purposes of this 
guidance if baseline risk remains less than 1 x 10-\4\/year 
for CDF and less than 1 x 10-\5\/year for LERF once the 
impact of the proposed change is incorporated into baseline risk.
    RIPE exemption requests must also include defense-in-depth (DID) 
and safety margin considerations assessed by the integrated decision-
making panel (IDP).
    Requests for changes made under the RIPE are reviewed by the NRC 
staff in a manner consistent with the principles of risk-informed 
decision-making outlined in Regulatory Guide 1.174, Revision 3, ``An 
Approach for Using Probabilistic Risk Assessment in Risk-Informed 
Decisions on Plant-Specific Changes to the Licensing Basis'' 
(ML17317A256), which includes ensuring that the proposed change is 
consistent with DID philosophy, maintains sufficient safety margins, is 
consistent with the Commission's Safety Goal Policy Statement, and 
includes performance monitoring strategies.

Conformance With the RIPE Minimal Safety Impact Criteria

    The licensee considered the RIPE screening questions contained in 
the SIC and concluded that the requested exemption would not have a 
more than minimal impact on safety. Considerations for each of the five 
screening questions are discussed below.
    1. Does the issue result in an adverse impact on the frequency of 
occurrence of an accident initiator or result in a new accident 
initiator?

[[Page 62808]]

    In Section 4.4 of the exemption request, the licensee states that 
the issue does not result in an adverse impact on the frequency of 
occurrence of an accident initiator or result in a new accident 
initiator because the cables impacted by the issue are associated with 
the solid state protection system (SSPS), which provides the logic to 
develop reactor trip and emergency safety feature actuation signals 
(ESFAS). The licensee also states that the SSPS provides a mitigation 
function and does not initiate an accident or create a new accident 
initiator.
    The NRC staff reviewed the licensee's consideration of this 
screening element and concluded that the issue does not adversely 
impact the frequency of occurrence of an accident initiator or result 
in a new accident initiator because the SSPS provides a mitigation 
function and does not initiate an accident.
    2. Does the issue result in an adverse impact on the availability, 
reliability, or capability of structures, systems, or components (SSCs) 
or personnel relied upon to mitigate a transient, accident, or natural 
hazard?
    In Section 4.4 of the exemption request, the licensee states that 
the issue does not result in an adverse impact on the availability, 
reliability, or capability of SSCs or personnel relied upon to mitigate 
a transient, accident, or natural hazard because the safety-related 
protection trains will remain fully capable of performing their 
intended functions. The licensee's conclusion is based on an evaluation 
that reviewed potential sources of electrical anomalies and the 
mitigation techniques used to reduce the probability of an event 
occurring that could impact plant equipment. The electrical anomaly 
evaluation is described in Section 4.1 of the exemption request and 
included evaluation of the cabinet design, cabinet location, electrical 
grounding, power source design, signal attenuation due to cable length, 
equipment qualification, cable routing, previous testing of low-level 
instrument wiring, plant operating experience, and the requirements in 
IEEE 384-1974, ``IEEE Trial-Use Standard Criteria for Separation of 
Class 1E Equipment and Circuits.'' The evaluation concludes that there 
are no credible electrical anomaly events which could impact either 
train of safety-related equipment from performing its design basis 
function.
    The license stated that the turbine trip logic connects to the SSPS 
and RPS through four control relays that use redundant contacts from 
the reactor trip breaker. In addition, the licensee stated the reactor 
trip breaker auxiliary contacts provide indication of a reactor trip to 
the turbine trip system (TTS) and that an open or short of the contacts 
used for the non-safety related portion of the circuit would not 
prevent a reactor trip from occurring, if required, because the 
auxiliary contacts are not in the direct electrical path of the reactor 
trip breakers. The cables and conduits for each of these circuits 
follow the separation criteria requirements except for Terminal Box B 
and TCS Cabinet G. The isolation between the TCS and the RPS/SSPS 
trains is provided in the RPS and SSPS cabinets.
    In the exemption request, the licensee stated that if a short 
circuit were to occur, the impact would be limited to a single train of 
the TTS and that multiple shorts would be needed to impact both TTS 
trains. In its supplement dated June 7, 2024, the licensee stated:

    A fault of the TTS cables could impact the non-safety-related 
automatic turbine trip on reactor trip function. For example, a 
fault could cause a short circuit which could bypass the SSPS 
turbine trip output relay contacts, thus preventing the turbine from 
tripping. If this were to occur and a reactor trip occurred, 
Operations would trip the turbine manually by the Main Control Board 
turbine trip switch per step 2 of [Harris] Emergency Operating 
Procedure EOP-E-0, ``REACTOR TRIP OR SAFETY INJECTION.''

    Under 10 CFR 50.62(c)(1), each pressurized-water reactor must have 
equipment, from sensor output to final actuation device, that is 
diverse from the reactor trip system, to automatically initiate the 
auxiliary feedwater system and initiate a turbine trip under conditions 
indicative of an anticipated transient without scram (ATWS). Harris 
complied with this requirement by installing ATWS mitigation system 
actuation circuitry (AMSAC). The NRC staff notes that AMSAC would 
remain available to trip the turbine if an ATWS were to occur.
    The NRC staff reviewed the licensee's consideration of this 
screening element and determined that an adverse impact to the 
availability, reliability, or capability of SSCs relied upon to 
mitigate a transient, accident, or natural hazard exists because the 
separation and channel independence requirements of IEEE 279-1971 are 
not met in TCS Cabinet G. However, the licensee's evaluation of the TCS 
circuitry demonstrates that, while the exemption would rely on non-
safety-related equipment to prevent potential electrical anomalies from 
propagating to safety-related components, the TCS design is robust and 
configured such that any electrical perturbations are unlikely. Should 
an electrical short condition result in failure of an automatic turbine 
trip, pre-existing procedurally directed operator actions are available 
to manually initiate the required turbine trip.
    The NRC staff concluded that the adverse impact of not meeting the 
separation and channel independence requirements of IEEE 279-1971, 
Section 4.6, for the RPS cables that terminate within TCS Cabinet G on 
the availability, reliability, or capability of SSCs or personnel 
relied upon to mitigate a transient, accident, or natural hazard is not 
more than minimal because (1) the design of the TCS ensures it is 
unlikely that an electrical anomaly event could occur that would 
prevent either train of safety-related equipment from performing its 
design basis function, (2) not meeting separation and channel 
independence requirements would not impact the reactor trip breakers 
because the turbine trip logic is not directly electrically connected 
the reactor trip breakers, and (3) operator actions and AMSAC would 
remain available to trip the turbine in the unlikely event that a fault 
prevented the turbine trip from occurring automatically.
    3. Does the issue result in an adverse impact on the consequences 
of an accident sequence?
    In Section 4.4 of the exemption request, the licensee stated that 
the issue does not affect the safety-related design functions of the 
SSPS or RPS. The licensee also states the design function of the SSPS 
to mitigate an accident is not impacted and therefore the consequences 
of any accident previously evaluated are not impacted. In its 
supplement dated June 7, 2024, the licensee stated that a fault of the 
TTS cables could impact the non-safety-related automatic turbine trip 
on reactor trip function, but procedurally directed operator actions 
would remain available to manually trip the turbine if needed.
    The NRC staff reviewed the licensee's consideration of this 
screening element and concluded that the proposed exemption does not 
result in an adverse impact on the consequences of an accident because 
the proposed exemption does not prevent the ability of the safety-
related systems to perform their design functions.
    4. Does the issue result in an adverse impact on the capability of 
a fission product barrier?
    In Section 4.4 of the exemption request, the licensee stated that 
the issue does not affect operating limits, the fuel, reactor coolant 
system (RCS), or modify the containment boundary in any way. The cables 
are located outside the containment building and do not result in 
revising or challenging a design

[[Page 62809]]

basis limit for a fission product barrier (i.e., numerical limiting 
value for controlling the integrity of the fuel cladding, reactor 
coolant pressure boundary, and/or containment) as described in the 
Updated Final Safety Analysis Report. Furthermore, the licensee stated 
the proposed exemption does not prevent the ability of the safety-
related systems to perform their design functions.
    The NRC staff reviewed the licensee's consideration of this 
screening element and concluded that the proposed exemption does not 
result in an adverse impact on the capability of a fission product 
barrier because the proposed exemption does not prevent the ability of 
safety-related systems, including RCS and containment, to perform their 
design functions or alter any design-basis limits.
    5. Does the issue result in an adverse impact on DID capability or 
impact in safety margin?
    In Section 4.4. of the exemption request, the licensee stated that 
there is no adverse impact on DID and safety margins because there are 
no credible events that would prevent both trains of safety-related 
equipment from fulfilling their design-basis functions. The licensee's 
conclusion is based on an evaluation of the potential for electrical 
anomalies described in Section 4.1 of the exemption request, which 
included evaluation of the cabinet design, cabinet location, electrical 
grounding, power source design, signal attenuation due to cable length, 
equipment qualification, cable routing, previous testing of low-level 
instrument wiring, plant operating experience, and the requirements in 
IEEE 384-1974. The evaluation concluded that there are no credible 
electrical anomaly events which could impact either train of safety-
related equipment from performing its design-basis function.
    The licensee stated that, based on the evaluation that established 
there are no credible events that would impact both trains of safety-
related equipment from performing its design-basis function, the key 
aspects of IEEE 279-1971 for single failure criterion and channel 
integrity are maintained. The licensee also stated that while the 
common connection for the ``A'' and ``B'' trains in the TCS does 
challenge the channel independence requirement of IEEE 279-1971, 
Section 4.6, there is not a credible reduction in the ability of the 
safety-related systems to perform their intended design functions. The 
licensee further stated that exemption to the IEEE 279-1971, Section 
4.6, requirement will not impact the ability of the safety-related 
protection trains to remain fully capable of performing their intended 
design functions in generating the signals associated with actuating 
reactor trip and engineered safeguards, as required by IEEE 279-1971.
    In its response to screening question 2, the licensee stated that 
the turbine trip logic connects to the SSPS and RPS through four 
control relays that use redundant contacts from the reactor trip 
breaker and that an open or short of the contacts used for the non-
safety related portion of the circuit would not prevent a reactor trip 
from occurring, if required, because the auxiliary contacts are not in 
the direct electrical path of the reactor trip breakers. The licensee 
also stated that the isolation between the TCS and the RPS/SSPS trains 
is provided in the RPS and SSPS cabinets. Further, the licensee stated 
that if a short circuit were to occur, the impact would be limited to a 
single train and the ability to trip the turbine would not be lost. In 
its supplement dated June 7, 2024, the licensee stated that a fault of 
the TTS cables could impact the non-safety-related automatic turbine 
trip on reactor trip function, but procedurally directed operator 
actions would remain available to manually trip the turbine if needed. 
In addition, the NRC staff notes that AMSAC would remain available to 
trip the turbine if an ATWS were to occur, such as due to multiple 
shorts occurring (which is outside of the single failure proof design 
criteria).
    The NRC staff reviewed the licensee's consideration of this 
screening element and determined that the licensee describes a 
potential adverse impact to DID and safety margins because the channel 
independence requirements of IEEE 279-1971 are not met in TCS Cabinet 
G. However, the licensee's evaluation of the TCS circuitry demonstrates 
that, while the exemption would rely on non-safety-related equipment to 
prevent potential electrical anomalies from propagating to safety-
related components, the TCS design is robust and configured such that 
any electrical perturbations are unlikely. In the unlikely event that 
an electrical condition results in failure of an automatic turbine 
trip, procedurally directed operator actions are available to manually 
trip the turbine. The use of pre-existing procedurally controlled 
operator actions to provide diversity and DID for this unlikely 
scenario does not result in the over-reliance on programmatic measures.
    The NRC staff concluded that the adverse impact of not meeting the 
separation and channel independence requirements of IEEE 279-1971, 
Section 4.6, for the RPS cables that terminate within TCS Cabinet G on 
DID capability and safety margins is not more than minimal because (1) 
the design of the TCS ensures it is unlikely that an electrical anomaly 
event could occur that would prevent either train of safety-related 
equipment from performing its design-basis functions, (2) not meeting 
channel independence requirements would not impact the reactor trip 
breakers because the turbine trip logic is not directly electrically 
connected the reactor trip breakers, and (3) operator actions and AMSAC 
would remain available to trip the turbine in the unlikely event that a 
fault prevented the turbine trip from occurring automatically.

Implementation of an IDP

    The licensee has been approved to adopt 10 CFR 50.69, ``Risk-
informed categorization and treatment of structures, systems and 
components for nuclear power reactors,'' by license amendment No. 174, 
issued September 17, 2019 (ML19192A012), as revised by license 
amendment No. 188, issued January 19, 2022 (ML21316A248). The licensee 
established a multi-disciplinary IDP to evaluate the proposed exemption 
request. The IDP membership included personnel from site engineering, 
operations, PRA, safety analysis, and licensing. Therefore, the NRC 
staff concludes that Harris used an acceptable IDP in support of the 
proposed exemption request per the RIPE guidance in TSG-DORL-2021-01.

Use of an Acceptable/Approved PRA Model

    Harris has adopted risk-informed initiative Technical 
Specifications Task Force (TSTF) traveler TSTF-505, Revision 2, 
``Provide Risk-Informed Extended Completion Times--RITSTF Initiative 
4b,'' for the risk-informed completion time program, as approved by 
license amendment No. 184, issued April 2, 2021 (ML21047A314). The 
Harris PRA model used to support the risk-informed completion time 
license amendment includes internal events, internal flooding, and fire 
hazards. The Harris PRA model does not include high winds, external 
flooding, or seismic hazards due to meeting screening criteria as part 
of the approval of its risk-informed completion time license amendment. 
There are no concerns in this exemption request specifically related to 
high winds, external flooding, or seismic hazards. Implementation of 
the TSTF-505 license amendment and associated license conditions have 
been completed. Therefore, the NRC staff concludes that Harris used a 
technically acceptable PRA model in support of the

[[Page 62810]]

proposed exemption request per the RIPE guidance in the SIC.

Evaluation of PRA Results

    The licensee quantitatively assessed the risk significance of 
maintaining the current TCS circuitry at Harris with the proposed 
exemption using a surrogate to represent the potential for a hot short 
to fail the ability of (1) the turbine to trip upon a reactor trip, (2) 
the reactor to trip upon a valid RPS signal, and (3) the ESFAS to 
actuate upon a valid actuation. The surrogate basic event was applied 
in the logic model where turbine trips, RPS signal failures, and ESFAS 
actuations were modeled. The surrogate basic event probability was 
based on the conditional probability of a hot short to occur during a 
conservative selection of fires that impact either train of SSPS. The 
risk results were 1.6 x 10-\8\/year for CDF and less than 1 
x 10-\10\/year for LERF. These results satisfy the RIPE 
criteria of contributing less than 1 x 10-\7\/year to CDF 
and 1 x 10-\8\/year to LERF. Cumulative risk results were 
4.1 x 10-\5\/year for CDF and 3.5 x 10-\6\/year 
for LERF. Therefore, cumulative risk for Harris remains less than the 
RIPE criteria of 1 x 10-\4\/year for CDF and 1 x 
10-\5\/year for LERF. The NRC staff concludes that these 
results satisfy the RIPE criteria for a minimal increase in risk for 
the proposed exemption.

Evaluation of the Need for Risk Management Actions

    Evaluation of the RIPE screening questions and the PRA results 
confirm that the proposed exemption results in a minimal safety impact. 
For these results, the SIC guidance states that risk management actions 
must be considered to offset the risk increase for the NRC staff to 
review under RIPE. Section 4.3 of the exemption request states that a 
review of industry operating experience related to the issue did not 
identify any specific modifications necessary to assess and/or bound 
the impact of the issue on quantitative risk. Therefore, the NRC staff 
concluded that no risk management actions were identified or required.

Assessment of Performance Monitoring Strategies

    Section 4.1 of the exemption request states that the TSC was 
upgraded in 2018 but the cables in question have not been moved since 
original plant construction. Both the previous and current designs 
energize the control circuits continuously so that a loss of power 
would result in a turbine trip. The previous design tested the circuit 
quarterly. The current design cycles the control relays weekly, and 
this test has been performed once a week for over 5 years. There have 
been no instances of spurious control circuit anomalies attributed to 
the TCS trip relays cycling on and off.
    The NRC staff concluded that the existing performance monitoring 
strategies will ensure no deficiencies exist that would challenge the 
conclusions in the licensee's evaluation of the proposed exemption.
A. The Exemption is Authorized by Law
    The NRC has the authority under 10 CFR 50.12 to grant exemptions 
from the requirements of Part 50 upon demonstration of proper 
justification. The licensee has requested an exemption to the 
requirement in 10 CFR 50.55a(h)(2) requiring protection systems meet 
the requirements of IEEE 279-1971, Section 4.6, for safety-related RPS 
cables that terminate within TCS Cabinet G. As discussed below, the NRC 
staff determined that special circumstances exist, which support 
granting the proposed exemption. Furthermore, granting the exemption 
would not result in a violation of the Atomic Energy Act of 1954, as 
amended, or the NRC's regulations. Therefore, the exemption is 
authorized by law.
B. The Exemption Presents No Undue Risk to Public Health and Safety
    The NRC staff has concluded that the exemption represents low risk, 
is of minimal safety impact, and that adequate DID and safety margins 
are preserved. The NRC staff concluded that the licensee's submittal 
demonstrates that the design of the TCS is robust against electrical 
failures that would prevent the RPS from performing their intended 
functions with the proposed exemption. Thus, granting this exemption 
request will not pose undue risk to public health and safety.
C. The Exemption Is Consistent With the Common Defense and Security
    The NRC staff has evaluated the licensee's exemption request and 
concluded that the licensee's submittal demonstrates that the design of 
the TCS is robust against electrical failures that would prevent the 
RPS from performing their intended functions with the proposed 
exemption. The NRC staff also concluded that adequate DID and safety 
margins will be preserved with the requested exemption. Further, the 
exemption does not involve security requirements and does not create a 
security risk. Therefore, the exemption is consistent with the common 
defense and security.
D. Special Circumstances
    Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii), 
are present whenever application of the regulation in the circumstances 
would not serve the purpose of the rule or is not necessary to achieve 
the purpose of the rule. The licensee has requested a limited scope 
exemption from 10 CFR 50.55a(h)(2) that would only apply to the RPS 
cables that terminate within TCS Cabinet G. Specifically, the exemption 
request would remove the requirement for the RPS cables that terminate 
within TCS Cabinet G to be independent and physically separated in 
accordance with IEEE 279-1971, Section 4.6. The underlying purpose of 
IEEE 279-1971, Section 4.6, is to ensure the capability of the safety-
related system to accomplish its safety function during normal and 
accident conditions and reduce the likelihood of interactions between 
channels during maintenance operations or in the event of a channel 
malfunction.
    The licensee has supported that the design of the TCS is adequate 
to ensure that the lack of independence and physical separation between 
TCS and RPS cables in TCS Cabinet G is unlikely to prevent either 
system from being able to perform their intended functions. In 
addition, the licensee has also demonstrated that adequate DID and 
safety margins will be preserved with the requested exemption. For 
these reasons, the NRC staff finds that for this limited scope 
exemption to the requirements of 10 CFR 50.55a(h)(2) for the safety-
related RPS cables that terminate within TCS Cabinet G, application of 
the regulation in the particular circumstances is not necessary to 
achieve the underlying purpose of the rule.
E. Environmental Considerations
    The exemption requested by the licensee includes changes to 
requirements with respect to installation or use of a facility 
component located within the restricted area. The NRC staff determined 
that the exemption meets the eligibility criteria for the categorical 
exclusion set forth in 10 CFR 51.22(c)(9) because the granting of this 
exemption involves: (i) no significant hazards consideration, (ii) no 
significant change in the types or a significant increase in the 
amounts of any effluents that may be released offsite, and (iii) no 
significant increase in individual or cumulative occupational radiation 
exposure. Therefore, in accordance with 10 CFR 51.22(b), no 
environmental impact statement or environmental assessment need be 
prepared in connection with the

[[Page 62811]]

NRC's consideration of this exemption request. The basis for the NRC 
staff's determination of each of the requirements in 10 CFR 51.22(c)(9) 
is discussed below.

Requirements in 10 CFR 51.22(c)(9)(i)

    The NRC staff evaluated the issue of no significant hazards 
consideration using the standards described in 10 CFR 50.92(c), as 
presented below:
    1. Does the proposed exemption involve a significant increase in 
the probability or consequences of an accident previously evaluated?
    Response: No.
    The design of the TCS is robust against electrical failures that 
would prevent the RPS from performing their intended functions with the 
proposed exemption and does not modify how the plant is operated. The 
proposed exemption does not affect any plant protective boundaries, 
cause a release of fission products to the public, or alter the 
performance of any SSCs important to safety.
    Therefore, the proposed exemption does not result in a significant 
increase in the probability or consequences of an accident previously 
evaluated.
    2. Does the proposed exemption create the possibility of a new or 
different kind of accident from any accident previously evaluated?
    Response: No.
    The design of the TCS is robust against electrical failures that 
would prevent the RPS from performing their intended functions with the 
proposed exemption and does not modify how the plant is operated. In 
addition, the TTS and RPS provide mitigation functions and do not 
initiate accidents or create a new accident initiators.
    Therefore, the proposed exemption does not create the possibility 
of a new or different kind of accident from any previously evaluated.
    3. Does the proposed exemption involve a significant reduction in a 
margin of safety?
    Response: No.
    The design of the TCS is robust against electrical failures that 
would prevent the RPS from performing their intended functions with the 
proposed exemption and does not modify how the plant is operated. The 
proposed exemption does not alter any setpoints for protective actions, 
change the initial conditions for any accidents, or alter the 
requirements of any SSCs important to safety.
    Therefore, the proposed exemption does not involve a significant 
reduction in a margin of safety.
    The NRC staff concludes that the proposed exemption presents no 
significant hazards consideration under the standards set forth in 10 
CFR 50.92(c), and, accordingly, a finding of no significant hazards 
consideration is justified (i.e., satisfies the provision of 10 CFR 
51.22(c)(9)(i)).

Requirements in 10 CFR 51.22(c)(9)(ii)

    The design of the TCS is robust against electrical failures that 
would prevent the RPS from performing their intended functions with the 
proposed exemption and does not modify how the plant is operated. The 
proposed exemption does not alter any setpoints for protective actions, 
change the initial conditions for any accidents, or alter the 
requirements of any SSCs important to safety. The proposed exemption 
will not significantly change the types or amounts of effluents that 
may be released offsite. Therefore, the staff finds that the provision 
of 10 CFR 51.22(c)(9)(ii) is satisfied.

Requirements in 10 CFR 51.22(c)(9)(iii)

    The licensee's request supported that the exemption had either no 
or a minimal safety impact for all accident initiator categories and 
the NRC staff has concluded that the proposed exemption will not result 
in an adverse impact on the frequency of existing accident initiators 
or result in new accident initiators. The proposed exemption will not 
significantly increase individual occupational radiation exposure, or 
significantly increase cumulative public or occupational radiation 
exposure. Therefore, the staff finds that the provision of 10 CFR 
51.22(c)(9)(iii) is satisfied.
    The NRC staff concludes that the proposed exemption meets the 
eligibility criteria for the categorical exclusion set forth in 10 CFR 
51.22(c)(9). Therefore, in accordance with 10 CFR 51.22(b), no 
environmental impact statement or environmental assessment need be 
prepared in connection with the NRC's proposed granting of this 
exemption.

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 Duke Energy an exemption from 
IEEE 279-1971, Section 4.6, as required by 10 CFR 50.55a(h)(2), for the 
safety-related RPS cables at Harris that terminate within TCS Cabinet 
G.

    Dated: July 29, 2024.

    For the Nuclear Regulatory Commission.

Michael Mahoney,

Project Manager, Division of Operating Reactor Licensing, Office of 
Nuclear Reactor Regulation.

[FR Doc. 2024-16978 Filed 7-31-24; 8:45 am]
BILLING CODE 7590-01-P