RS-24-050, Additional Information Supporting Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation

Additional Information Supporting Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation

ML24130A221
Person / Time
Site:	Clinton
Issue date:	05/09/2024
From:	Humphrey M Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RS-24-050
Download: ML24130A221 (1)

Text

4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office

RS-24-050

May 9, 2024

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRC Docket No. 50-461

Subject:

Additional Information Supporting Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation

References:

1. Letter from K. Lueshen (Constellation Energy Generation, LLC) to U.S. NRC, "Request for License Amendment to Revise Technical Specifications Related to Reactor Water Cleanup Isolation Instrumentation," dated August 21, 2023

2. Email from J. Wiebe (U.S. NRC) to K. Nicely (Constellation Energy Generation, LLC), "L-2023-LLA-0118 - Request for Additional Information,"

dated May 3, 2024

In Reference 1, Constellation Energy Generation, LLC (CEG) requested an amendment to Facility Operating License No. NPF-62 for Clinton Power Station, Unit 1. The proposed change revises the Reactor Water Cleanup system isolation functions that are listed in Technical Specifications (TS) 3.3.6.1, "Primary Containment and Drywell Isolation Instrumentation,"

Table 3.3.6.1-1, "Primary Containment and Drywell Isolation Instrumentation."

The NRC requested additional information that is needed to complete review of the proposed change in Reference 2. In response to this re quest, CEG is providing the attached information.

CEG has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in Attachment 1 of Reference 1. The additional information provided in this submittal does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration. In addition, the additional information provided in this submittal does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

May 9, 2024 U.S. Nuclear Regulatory Commission Page 2

There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Mr. Nick Lien at (779) 231-6283.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 9th day of May 2024.

Respectfully, Humphrey, Digitally signed by Humphrey, Mark D.

Mark D. Date: 2024.05.09 13:15:25

-05'00' Mark D. Humphrey Sr. Manager Licensing Constellation Energy Generation, LLC

Attachment:

Response to Request for Additional Information

cc: NRC Regional Administrator, Region III NRC Senior Resident Inspector - Clinton Power Station Illinois Emergency Management Agency - Division of Nuclear Safety ATTACHMENT Response to Request for Additional Information

RAI 1

Provide a summary of the calculation(s) that evaluate high energy line breaks in the reactor water cleanup (RWCU) pump rooms and credit the temperature isolation.

Response

Calculation ATD-0278 evaluates high energy line breaks (HELB) in the RWCU pump rooms. As stated in this calculation, the mass and energy release uses a detection time of 0.7 seconds due to ambient temperature detection to initiate valve closure. This is much faster than the differential flow time delay of 45 seconds, and therefore, is unaffected by the proposed changes to the differential flow setpoints.

The HELB in the RWCU pump rooms was re-evaluated for extended power uprate (EPU) conditions in calculation EPU-T1009, using the same inputs, assumptions, and methodology as ATD-0278. The EPU analysis agreed with the ATD-0278 analysis within acceptable limits and concluded there are no adverse effects on the environmental parameters determined in ATD-0278 due to EPU.

RAI 2

Do the RWCU rooms have watertight doors? Can a line break in the RWCU pump rooms leak into the auxiliary building hallway such that the water flows down the floor plugs into the emergency core cooling system cubicles?

Response

The RWCU pump rooms do not have watertight doors, and a line break in this area could flood into the Auxiliary Building hallway. However, the floor plugs in the Auxiliary Building hallway that are above the Emergency Core Cooling System (ECCS) cubicles have seals to prevent a flood from leaking down into the ECCS cubicles.

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