ML24058A246

– Supplemental Information Needed for Using the Risk-Informed Process for Evaluations for the Request for Exemption from Certain Requirements in 10 CFR 50.55a(h)(2)

ML24058A246
Person / Time
Site:	Harris
Issue date:	03/18/2024
From:	Michael Mahoney Plant Licensing Branch II
To:	Haaf T Duke Energy Progress
Mahoney M
References
EPID L-2024-LLE-0004
Download: ML24058A246 (1)

Text

March 18, 2024

Mr. Thomas P. Haaf Site Vice President Shearon Harris Nuclear Power Plant Mail Code NHP01 5413 Shearon Harris Road New Hill, NC 27562-9300

SUBJECT:

SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1 - SUPPLEMENTAL INFORMATION NEEDED FOR USING THE RISK-INFORMED PROCESS FOR EVALUATIONS FOR THE REQUEST FOR EXEMPTION FROM CERTAIN REQUIREMENTS IN 10 CFR 50.55a(h)(2) (EPID L-2024-LLE-0004)

Dear Mr. Haaf:

By letter dated February 6, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24037A284), Duke Energy Progress, LLC (Duke Energy) submitted a request for an exemption from certain requirements of Title 10 of the Code of Federal Regulations, Section 50.55a(h)(2), Protection systems, for the Shearon Harris Nuclear Power Plant, Unit 1 (Harris). Specifically, the exemption request would remove the requirement for the Reactor Protection System cables that term inate within the Turbine Control System Cabinet G (1TCS-CAB-G) to meet the requirement in IEEE 279-1971, Criteria for Protection Systems for Nuclear Power Generating Stations, Section 4.6, Channel Independence, that the cables be independent and physically separated. The exemption request was submitted under the Risk-Informed Process for Evaluations (RIPE).

The NRC staff has reviewed your application and concluded that the information delineated in the enclosure to this letter is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed exemption in terms of using RIPE.

In order to make the application complete, the NRC staff requests that Duke Energy supplement the application to address the information requested in the enclosure by April 3, 2024. This will enable the NRC staff to begin its review under the RIPE. If the information responsive to the NRC staffs request is not received by the abov e date, the application will not be accepted for review pursuant to 10 CFR 2.101, Filing of application, and the NRC will cease its activities associated with the application. If the application is subsequently accepted for review, you will be advised of any further information needed to support the staffs detailed technical review by separate correspondence.

The information requested and associated time frame in this letter were discussed with Ryan Treadway of your staff on March 18, 2024.

T. Haaf

If you have any questions, please contact me at 301-415-3867 or via e-mail at Michael.Mahoney@nrc.gov.

Sincerely,

/RA/

Michael Mahoney, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket No. 50-400

Enclosure:

Supplemental Information Needed

cc: Listserv

SUPPLEMENTAL INFORMATION NEEDED

REQUEST FOR EXEMPTION FROM CERTAIN REQUIREMENTS

IN 10 CFR 50.55a(h)(2) USING THE RISK-INFORMED PROCESS FOR EVALUATIONS

DUKE ENERGY PROGRESS, LLC

SHEARON HARRIS NUCLEAR POWER PLANT, UNIT 1

DOCKET NO. 50-400

By letter to the U.S. Nuclear Regulatory Commission (NRC) dated February 6, 2024 (Agencywide Documents Access and Managem ent System (ADAMS) Accession No. ML24037A284), Duke Energy Progress, LLC (Duke Energy or the licensee) submitted a request for an exemption from certain requirements of Title 10 of the Code of Federal Regulations, Section 50.55a(h)(2), Protection systems, for the Shearon Harris Nuclear Power Plant, Unit 1 (Harris).

Specifically, the exemption request would remove the requirement for the Reactor Protection System cables that terminate within the Turbi ne Control System Cabinet G (1TCS-CAB-G) to meet the requirement in IEEE 279-1971, Criteria for Protection Systems for Nuclear Power Generating Stations, Section 4.6, Channel Independence, that the cables be independent and physically separated.

The NRC staff has reviewed your application and c oncluded more information is necessary to enable the staff to make an independent assessment regarding the acceptability of the proposed exemption in terms of using the Risk-Informed Process for Evaluations (RIPE).

The NRC staff has identified information insuffic iencies related to how the request addresses the following screening questions from NRCs Gui delines for Characterizing the Safety Impact of Issues, Revision 2, May 2022 (ML22088A135), Section 4.1, Screening for No Impact, regarding any adverse impact on safety:

Question 2: Does the issue result in an adverse impact on the availability, reliability, or capability of SSCs [systems, structures, and components] or personnel relied upon to mitigate a transient, accident, or natural hazard?

Question 5: Does the issue result in an adverse impact on defense-in-depth capability or impact in safety margin?

NRCs Nuclear Reactor Regulation Temporary Staff Guidance, Risk-Informed Process for Evaluations, TSG-DORL-2021-01, Revision 3 (ML23122A014), states, in part:

Changes made under RIPE are reviewed by staff in a manner consistent with the principles of risk-informed decision-making (RIDM) outlined in Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decision on Plant-Specific Changed to the Licensing Basis, which included ensuring that the proposed change meets current regulations (unless an exemption is requested), is

Enclosure

consistent with defense-in-depth (DID) philosophy, maintains sufficient safety margins (SM), is consistent with the Commissions Safety Goal Policy Statement, and included performance monitoring strategies.

Based on the staffs review and the information addressed above, the staff has identified that in the unlikely event of a fire in the Turbine Control System (TCS) Cabinet G (1TCS-CAB-G), the lack of separation between class and non-class 1E components could have adverse impacts on the Reactor Protection System (RPS) cables, whic h terminate in that cabinet. While the licensee has determined that this event is not credible, RG 1.174 provides guidance that licensees demonstrate that defense-in-depth and safety margins are maintained to ensure those adverse impacts are minimal.

The staff requests that the licensee provides evaluations as supplemental responses to Questions 2 and 5 in Section 4.4 of the exemption request that adequately evaluate the potential adverse impacts to defense-in-depth a nd safety margins to enable the NRC staff to process the exemption request under RIPE.

ML24058A246 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LA NRR/DRA/APOB/BC NAME MMahoney ABaxter AZoulis DATE 02/27/2024 02/28/2024 02/28/2024 OFFICE NRR/DORL/LPL2-2/BC NRR/DORL/LPL2-2/PM NAME DWrona MMahoney DATE 02/29/2024 03/18/2024