ML22320A113

Generation Station, Units 1 and 2 - Supplemental Information Needed for Acceptance of Digital Instrumentation and Controls License Amendment Requests

ML22320A113
Person / Time
Site:	Limerick
Issue date:	11/21/2022
From:	Marshall M Plant Licensing Branch 1
To:	Rhoades D Constellation Energy Generation
Michael Marshall
References
EPID L-2022-LLA-0140
Download: ML22320A113 (4)

Text

November 21, 2022 Mr. David P. Rhoades Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer Constellation Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LIMERICK GENERATION STATION, UNITS 1 AND 2 - SUPPLEMENTAL INFORMATION NEEDED FOR ACCEPTANCE OF DIGITAL INSTRUMENTATION AND CONTROLS LICENSE AMENDMENT REQUESTS (EPID L-2022-LLA-0140)

Dear Mr. Rhoades:

By letter dated September 26, 2022 (Agencywide Documents Access and Management System (ADAMS) No. ML22269A569), as supplemented by letter dated August 12, 2022 (ML22224A149), Constellation Energy Generation, LLC (Constellation) submitted license amendment requests for Limerick Generation Station, Units 1 and 2 (Limerick). The proposed amendment requests would change both the design and technical specifications to permit the use of a new single digital instrumentation and controls system to replace analog instrumentation of reactor protection system, analog nuclear steam supply shutoff system, emergency core cooling system, reactor core isolation cooling system, and end-of-cycle recirculation pump trip at Limerick. In addition, the proposed amendments would:

change the classification of the redundant reactivity control system from safety-related to non-safety-related eliminate the automatic redundant reactivity control system feedwater runback function eliminate the automatic isolation function for the turbine enclosure main steam line tunnel temperature high indication eliminate several surveillance requirements allow the use of automated operator aids (or automated controls) from main control room The purpose of this letter is to provide the results of the U.S. Nuclear Regulatory Commission (NRC) staffs acceptance review of these amendment requests. The acceptance review was performed to determine if there is sufficient technical information in scope and depth to allow the NRC staff to complete its detailed technical review. The acceptance review is also intended to

P. Rhoades identify whether the application has any readily apparent information insufficiencies in its characterization of the regulatory requirements or the licensing basis of the plant.

Consistent with Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR), an application for an amendment to a license (including the technical specifications) must fully describe the changes requested, and following as far as applicable, the form prescribed for original applications. Section 50.34 10 CFR addresses the content of technical information required. This section stipulates that the submittal address the design and operating characteristics, unusual or novel design features, and principal safety considerations.

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 amendment in terms of regulatory requirements for the protection of public health and safety and the environment.

To make the application complete, the NRC staff requests that Constellation supplement the application to address the information requested in the enclosure within 13 calendar days of the date of this letter. This will enable the NRC staff to begin its detailed technical review. If the information responsive to the NRC staffs request is not received by the above date, the application will not be accepted for review pursuant to 10 CFR 2.101, 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.

If you have any questions, please contact me at (301) 415-2871 or michael.marshall@nrc.gov or Mr. Bhagwat BP Jain at (301) 415-6303 or bhagwat.jain@nrc.gov.

Sincerely,

/RA/

Michael L. Marshall, Jr, Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353

Enclosure:

Supplemental Information Needed cc: Listserv

SUPPLEMENTAL INFORMATION NEEDED AMENDMENT REQUEST INVOLVING DIGITAL INSTRUMENTATION AND CONTROLS CONSTELLATION ENERGY GENERATION, LLC LIMERICK GENERATION STATION, UNIT NOS 1 AND 2 DOCKET NOS. 50-352 AND 50-353 By letter dated September 26, 2022(Agencywide Documents Access and Management System (ADAMS) No. ML22269A569), as supplemented by letter dated August 12, 2022 (ML22224A149), Constellation Energy Generation, LLC (Constellation) submitted license amendment requests for Limerick Generation Station, Units 1 and 2 (Limerick). The proposed amendment requests would change both the design and technical specifications to permit the use of a new single digital instrumentation and controls system to replace analog instrumentation of reactor protection system, analog nuclear steam supply shutoff system, emergency core cooling system, reactor core isolation cooling system, and end-of-cycle recirculation pump trip at Limerick. In addition, the proposed amendments would change the classification of the redundant reactivity control system from safety-related to non-safety-related, eliminate the automatic redundant reactivity control system feedwater runback function, eliminate the automatic isolation function for the turbine enclosure main steam line tunnel temperature high indication, eliminate several surveillance requirements, and allow the use of automated operator aids (or automated controls) from main control room.

In the defense-in-depth and diversity analysis and licensing technical report attached to the supplement dated August 12, 2022, Constellation describes how the component interface module (CIM) is used in the plant protection system planned for Limerick. Descriptions of CIM diversity, priority logic, component control logic, diagnostics, extensive testing, and priority module function are provided. With regards to the CIM internal design (or technical description) references are provided to WCAP-17179-P, Revision 2, AP1000 Component Interface Module Technical Report, and WCAP-17179-P, Revision 6. On November 10, 2022, a public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and Constellation representatives regarding the status of the NRC staffs acceptance review. During the meeting, Constellation explained the use of the CIM for the priority module function in the proposed plant protection system. Also, Constellation described the difference between the CIM description in the WCAP-17179-P, Revision 2, and WCAP-17179-P, Revision 6.

The NRC staff has reviewed the application and considered the statements made by Constellation at the public meeting. The NRC staff has concluded that information about the CIM design is necessary for the staff to make an independent assessment regarding the acceptability of the license amendment requests. To support the acceptance review, the NRC staff requests that Constellation provide a technical description of the CIM design for the priority functions being used in the proposed plant protection system. Further, the description should address the conformance of the CIM design to the command prioritization positions described in Digital Interim Staff Guidance 04, Revision 1, Highly-Integrated Control Rooms -

Communications Issues (HICRc), specific to the Limerick proposed plant protection system design.

Enclosure

ML22320A113 OFFICE NRR/DORL/LPL1PM NRR/DORL/LPL1/LA NRR/DEX/EICB/BC NAME MMarshall KZeleznock MWaters DATE 11/16/2022 11/17/2022 11/17/2022 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME HGonzález MMarshall DATE 11/17/2022 11/21/2022