ML23290A009

Closeout of Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors

ML23290A009
Person / Time
Site:	Callaway
Issue date:	10/17/2023
From:	Mahesh Chawla Plant Licensing Branch IV
To:	Diya F Union Electric Co
Chawla M
References
EPID L-2017-LRC-0000
Download: ML23290A009 (1)

Text

October 17, 2023 Mr. Fadi Diya Senior Vice President and Chief Nuclear Officer Ameren Missouri Callaway Energy Center 8315 County Road 459 Steedman, MO 65077

SUBJECT:

CALLAWAY PLANT, UNIT NO. 1 - CLOSEOUT OF GENERIC LETTER 2004-02, POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS (EPID L-2017-LRC-0000)

Dear Mr. Diya:

By letter dated September 13, 2004 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML042360586), the U.S. Nuclear Regulatory (NRC) issued Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, requesting that licensees address the issues raised by Generic Safety Issue-191 (GSI-191), Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance.

The purpose of GL 2004-02 was to demonstrate compliance with Title 10 of the Code of Federal Regulations (10 CFR) Section 50.46, Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors. Specifically, the GL requested licensees to perform an evaluation of the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation systems and, if necessary, take additional action to ensure that the thermal insulation and other materials from broken pipes do not block the ECCS sump strainers or flow paths and prevent coolant from entering the reactor core. Lack of coolant in the core could cause core damage and containment failure.

By letter dated September 24, 2019 (ML19268A169), Union Electric Company, doing business as (dba) Ameren Missouri (the licensee) provided a response to GL 2004-02 for the Callaway Plant, Unit No. 1. By letter dated March 31, 2021 (ML21090A184), as supplemented by letters dated May 27, 2021, July 22, 2021, August 23, 2021, October 7, 2021, January 27, 2022, March 8, 2022, May 26, 2022, and September 8, 2022 (ML21147A222, ML21203A192, ML21237A135, ML21280A378, ML22027A804, ML22068A027, ML22146A337, and ML22251A343, respectively), the licensee provided its license amendment request to revise its technical specifications to address the concerns in GSI-191 and respond to GL 2004-02. In addition to the license amendment, the licensee requested exemptions pursuant to 10 CFR 50.12, Specific exemptions, from certain requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion (GDC) 35, Emergency core cooling; GDC 38, Containment heat removal;

and GDC 41, Containment atmosphere cleanup, to allow use of a risk-informed methodology instead of the traditional deterministic methodology to resolve the concerns associated with GSI-191 and respond to GL 2004-02 for Callaway.

The NRC staff performed a thorough review of all responses provided by the licensee and finds that the licensee provided adequate information as requested by GL 2004-02. The NRC staff conclusions have been documented in letters dated October 21, 2022 (ML22220A132 and Package ML22220A162). The NRC staff finds that the information provided demonstrates that debris will not inhibit the ECCS or CSS performance of its intended function in accordance with 10 CFR 50.46. Therefore, the NRC staff finds that the licensees responses to GL 2004-02 are adequate and considers GL 2004-02 closed for the Callaway Plant, Unit No. 1. No further information or action is requested of the licensee.

If you have any questions, please contact me at 301-415-8371 or via email at Mahesh.Chawla@nrc.gov.

Sincerely,

/RA/

Mahesh L. Chawla, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-483 cc: Listserv

ML23290A009

• by email OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA*

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NAME MChawla PBlechman SMehta DATE 10/17/2023 10/17/2023 10/17/2023 OFFICE NRR/DORL/LPL4/BC*

NRR/DORL/LPL4/PM*

NAME JDixon-Herrity MChawla DATE 10/17/2023 10/17/2023