ML22290A084

NRR E-mail Capture - Dresden 2 and 3 - RAI License Amendment Request Regarding New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies

ML22290A084
Person / Time
Site:	Dresden
Issue date:	10/13/2022
From:	Shilpa Arora NRC/NRR/DORL/LPL3
To:	Palutsis L Exelon Generation Co
References
L-2022-LLA-0085
Download: ML22290A084 (5)

Text

From: Surinder Arora Sent: Thursday, October 13, 2022 7:39 AM To: Palutsis, Linda M:(Constellation Nuclear)

Cc: Mathews, Mitchel A:(Constellation Nuclear); Nancy Salgado

Subject:

Dresden 2 and 3 - RAI RE: License Amendment Request Regarding New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies (EPID L-2022-LLA-0085)

Linda M. Palutsis:

By letter dated June 8, 2022, Constellation Energy Generation, LLC (CEG, the Licensee) submitted an amendment request regarding new fuel storage vault and spent fuel pool criticality methodologies with a proposed change to technical specification section 4.3.1 for Dresden Nuclear Power Station, Units 2 and 3. The Nuclear Regulatory Commission (NRC) staff is currently reviewing this amendment request and has identified the areas where additional information is required to complete its review. This email includes NRC staffs request for additional information (RAI) required on your submittal. In your email response dated October 12, 2022, you confirmed that CEG does not need a clarification call for the draft RAI which was sent to you on the same date.

Therefore, the NRC staff expects a response to this RAI within 30 days of this message which is by November 12, 2022. If CEG cannot provide a response as requested, please contact me to discuss.

Thanks, Surinder Arora, PE Project Manager, NRR/DORL/LPL3 surinder.arora@nrc.gov 301-415-1421 REQUEST FOR ADDITIONAL INFORMATION OFFICE OF NUCLEAR REACTOR REGULATION CONSTELLATION ENERGY GENERATION, LLC DOCKET NOS. 50-237, AND 50-249 EPID: L-2022-LLA-0085 By letter to the U.S. Nuclear Regulatory Commission (NRC) dated June 8, 2022, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22159A310)

Constellation Energy Generation, LLC (CEG, or the licensee) submitted a request for amendments to Renewed Facility Operating License Nos. DPR-19 and DPR-25 for Dresden Nuclear Power Station (DNPS) Units 2 and 3. Specifically, the amendment request is proposing a new criticality safety analysis (CSA) methodology for performing the criticality safety evaluation for legacy fuel types in addition to the GNF3 reload fuel in the spent fuel pool (SFP).

The amendment request is also proposing a change to the new fuel vault (NFV) CSA to utilize the GESTAR II methodology for validating the NFV criticality safety for GNF3 fuel in the General Electric (GE) designed NFV racks.

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

SFNB RAIs:

Regulatory Requirements:

Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix A, Criterion 5 requires, Structures, systems, and components important to safety shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown.

10 CFR Part 50, Appendix A, Criterion 62 requires, Criticality in the fuel storage and handling system shall be prevented by physical systems or processes, preferably by use of geometrically safe configurations.

Paragraph 50.68(a) of 10 CFR requires, Each holder of a construction permit or operating license for a nuclear power reactor issued under this part or a combined license for a nuclear power reactor issued under Part 52 of this chapter, shall comply with either 10 CFR 70.24 of this chapter or the requirements in paragraph (b) of this section. The licensee has chosen to comply with Paragraph 50.68(b) of 10 CFR.

Paragraph 50.68(b)(2) of 10 CFR requires, The estimated ratio of neutron production to neutron absorption and leakage (k-effective) of the fresh fuel in the fresh fuel storage racks shall be calculated assuming the racks are loaded with fuel of the maximum fuel assembly reactivity and flooded with unborated water and must not exceed 0.95, at a 95 percent probability, 95 percent confidence level. This evaluation need not be performed if administrative controls and/or design features prevent such flooding or if fresh fuel storage racks are not used.

Paragraph 50.68(b)(3) of 10 CFR requires, If optimum moderation of fresh fuel in the fresh fuel storage racks occurs when the racks are assumed to be loaded with fuel of the maximum fuel assembly reactivity and filled with low-density hydrogenous fluid, the k-effective corresponding to this optimum moderation must not exceed 0.98, at a 95 percent probability, 95 percent confidence level. This evaluation need not be performed if administrative controls and/or design features prevent such moderation or if fresh fuel storage racks are not used.

RAI-SFNB-1:

In Section 2.2 New Fuel Vault Criticality Safety Analysis of Attachment 1 to the June 8, 2022 letter, it states, The DNPS NFV racks are GE designed low density racks with a center-to-center spacing within a given row of 6.625 inches and an interrack spacing of 11.06 inches. The NFV rack CSA coverage for the new GNF3 fuel will be the GESTAR II (Reference 6.2) analysis for GE designed low density NFV racks, upon approval of this proposed license amendment.

The previous NFV CSA will no longer be applicable to DNPS upon implementation of this license amendment because the only fuel to be delivered to the site for core reloads will be GNF3.

However, Reference 6.2, GE Licensing Topical Report NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel (GESTAR II, Main)," Revision 31, dated November 2020 (ADAMS Accession Number ML20330A197/ML20330A198 (proprietary version) and ML20330A199 (non-proprietary version)) does not contain a nuclear criticality safety methodology or nuclear criticality safety analysis. To expedite its review of the licensees amendment request regarding storage of fuel assemblies in its NFV and SFP, the NRC conducted an audit of the documentation supporting the amendment request. During the audit, it was discovered that there is no generic NFV criticality safety analysis methodology. Instead, there is a fuel design specific NFV criticality safety analysis. In order to set the fuel design specific NFV criticality safety analysis as the Analysis of Record for the licensee, the fuel design specific NFV criticality safety analysis needs to be on the docket. Therefore, the NRC staff requests the licensee submit the fuel design specific NFV criticality safety analysis so that the NRC staff can determine whether this analysis demonstrates compliance with the regulatory requirements identified above.

RAI-SFNB-2:

The NFV has a standard cold core geometry (SCCG) limit of less than or equal to 1.31 k-effective (keff) and the proposed Technical Specification (TS) 4.3.1.1.c SFP SCCG limit is less than or equal to 1.33 keff. This indicates that fuel assemblies that are acceptable for storage in the SFP cannot be stored in the NFV. Describe how the fuel assemblies at DNPS are controlled in order to ensure that fuel assemblies with a SCCG of between 1.31 and 1.33 k eff are not inadvertently loaded in the NFV.

Hearing Identifier: NRR_DRMA Email Number: 1810 Mail Envelope Properties (BY3PR09MB82250942B2E11326720D33CA94259)

Subject:

Dresden 2 and 3 - RAI RE: License Amendment Request Regarding New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies (EPID L-2022-LLA-0085)

Sent Date: 10/13/2022 7:38:59 AM Received Date: 10/13/2022 7:38:00 AM From: Surinder Arora Created By: Surinder.Arora@nrc.gov Recipients:

"Mathews, Mitchel A:(Constellation Nuclear)" <Mitchel.Mathews@constellation.com>

Tracking Status: None "Nancy Salgado" <Nancy.Salgado@nrc.gov>

Tracking Status: None "Palutsis, Linda M:(Constellation Nuclear)" <Linda.Palutsis@constellation.com>

Tracking Status: None Post Office: BY3PR09MB8225.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 7244 10/13/2022 7:38:00 AM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: