ML21077A190

NRR E-mail Capture - Lasalle Units 1 and 2 - Request for Additional Information (RAI) Request for License Amendment Regarding Ultimate Heat Sink, (EPID-L-2020-LLA-0165)

ML21077A190
Person / Time
Site:	LaSalle
Issue date:	03/18/2021
From:	Bhalchandra Vaidya NRC/NRR/DORL/LPL3
To:	Taken J Exelon Generation Co
References
L-2020-LLA-0165
Download: ML21077A190 (3)

Text

From: Vaidya, Bhalchandra Sent: Thursday, March 18, 2021 10:45 AM To: Taken, Jason C.:(Exelon Nuclear); Kusumawatimurray, Putri:(GenCo-Nuc)

Subject:

LASALLE UNITS 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION (RAI) RE:

REQUEST FOR LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK, (EPID-L-2020-LLA-0165)

SUBJECT:

LASALLE UNITS 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION (RAI) RE: REQUEST FOR LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK, (EPID-L-2020-LLA-0165)

Jason and Dwi, By letter to the U.S. Nuclear Regulatory Commission (NRC) dated July 17, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20204A775), as supplemented by letters dated September 11 and October 22, 2020 (ADAMS Accession No. ML20259A454 and ML20296A456, respectively), Exelon Generation Company, LLC (EGC, the licensee) submitted a request to amend Technical Specification 3.7.3, "Ultimate Heat Sink," for the LaSalle County Station, Units 1 and 2, to expand the TS temperature limit of the cooling water supplied to the plant from the UHS to vary with the diurnal cycle by changing the average sediment level limit in the UHS to 6 inches.

The U.S. Nuclear Regulatory Commission (NRC) staff currently reviewing your submittals. The NRC staff has identified areas where additional information is needed to complete its review. The Request For Additional Information (RAI) is provided below.

==

REQUEST FOR ADDITIONAL INFORMATION OFFICE OF NUCLEAR REACTOR REGULATION Exelon Generation Co., LLC DOCKET NOS. 50-373, AND 50-374 EPID: L-2020-LLA-0165 RAI-STSB-1:

BASIS FOR THE REQUEST:

On July 17, 2020, Exelon Generation Company, LLC (the licensee) requested a change to the Technical Specifications (TS) of LaSalle County Station, Units 1 and 2.

In their request, the licensee proposed to delete the Ultimate Heat Sink (UHS) bottom elevation limit from TS 3.7.3 Condition A and remove the associated TS Surveillance Requirement (SR) 3.7.3.3. The licensee justified this change by stating:

The current TS SR 3.7.3.3 verifies Core Standby Cooling System (CSCS) pond bottom elevation is less than or equal to 686.5 feet. The proposed change would delete TS SR 3.7.3.3 because the requirement to ensure adequate long term cooling can be maintained through verification of average sedimentation level as proposed in TS SR 3.7.3.2. The use of average sedimentation depth of no greater than 6 inches ensures that a sufficient UHS volume remains for use during a design basis accident.

REGULATORY ANALYSIS BASIS:

Title 10 of the Code of Federal Regulations (CFR) Part 50.36(c)(3), describes SRs as requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation (LCO) will be met. The request above is needed to assure appropriate parameters are verified and LCO 3.7.3, Core Standby Cooling System pond operable, will be met.

REQUEST FOR ADDITIONAL INFORMATION:

It is unclear from the request how the sedimentation level correlates with UHS water volume. Please provide an explanation on how the necessary UHS water volume, an essential parameter used in the safety analysis (Updated Safety Analysis Report (UFSAR) Section 9.2.6), will be ensured by only verifying average sedimentation.

In addition, the current SR 3.7.3.3, which is proposed for removal, validates the lower elevation and would seem to establish a bottom, above which sediment may be measured to determine available water volume in the UHS. Please provide a detailed justification for removing SR 3.7.3.3, including how the UHS volume is validated without that established lower elevation.

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On March 16, 2021, during the clarification telephone discussion, you committed to respond to this RAI no later than 30 calendar days from the date of this communication.

If you have any questions, please contact me at (301) 415-3308, or by email at bhalchandra.vaidya@nrc.gov Bhalchandra K. Vaidya US Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing LPL3 301-415-3308 Bhalchandra.vaidya@nrc.gov

Hearing Identifier: NRR_DRMA Email Number: 1076 Mail Envelope Properties (DM8PR09MB7208F3E0281F57B000BBC20B8D699)

Subject:

LASALLE UNITS 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION (RAI)

RE: REQUEST FOR LICENSE AMENDMENT REGARDING ULTIMATE HEAT SINK, (EPID-L-2020-LLA-0165)

Sent Date: 3/18/2021 10:45:13 AM Received Date: 3/18/2021 10:45:13 AM From: Vaidya, Bhalchandra Created By: Bhalchandra.Vaidya@nrc.gov Recipients:

"Taken, Jason C.:(Exelon Nuclear)" <Jason.Taken@exeloncorp.com>

Tracking Status: None "Kusumawatimurray, Putri:(GenCo-Nuc)" <Putri.Kusumawatimurray@exeloncorp.com>

Tracking Status: None Post Office: DM8PR09MB7208.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 4216 3/18/2021 10:45:13 AM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: