ML22243A032

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Presentation Material for 9/7/22 Pre-Submittal Meeting Supplement to the Spent Fuel Pool Criticality Safety Analysis
ML22243A032
Person / Time
Site: Millstone Dominion icon.png
Issue date: 09/07/2022
From:
Dominion Energy Nuclear Connecticut
To:
NRC/NRR/DORL/LPL1
Guzman R
References
EPID L-2022-LRM-0058
Download: ML22243A032 (15)
v • d • e


Text

Millstone Power Station Unit 3 (MPS3)

Supplement to the Spent Fuel Pool (SFP) Criticality Safety Analysis (CSA)

September 7, 2022 1

MPS3 - Supplement to the SFP CSA Agenda

  • Background
  • Reason for Request
  • Proposed Resolution
  • Proposed Justification for Submittal
  • Submittal Conclusion
  • Schedule September 7, 2022 2

MPS3 - Supplement to the SFP CSA

Background

  • Three different SFP rack types at MPS3:
  • Region 1 - Boral poisoned, flux trap design
  • Region 1B: Two rows closest to SFP wall
  • Region 1A: Remaining rows of Region 1
  • Region 2 - Boral poisoned, non-flux trap design
  • Region 3 - Uncredited Boraflex, flux trap design September 7, 2022 3

MPS3 - Supplement to the SFP CSA Background (cont.)

  • Current CSA was submitted in 2018 and approved in 2019
  • Analysis has a modern CSA methodology based on NEI 12-16, Revision 3 (current Revision at the time of approval)
  • Current CSA takes credit for burnup
  • CSA demonstrated that the burnable poison (BP) WABA bounds IFBA during depletion
  • Technical Specification burnup curves assume assemblies contain maximum WABA during depletion September 7, 2022 4

MPS3 - Supplement to the SFP CSA Background (cont.)

  • Current CSA did not have any discussion on the use of gadolinia as a burnable poison
  • The SE, accordingly, did not have any discussion on the use of gadolinia
  • Citing NEI 12-16 alone is not sufficient for including gadolinia, the applicability of previous work must be demonstrated
  • This is stated in the RG 1.240, C.1.p clarification
  • This is also stated in the 2018 North Anna CSA SE September 7, 2022 5

MPS3 - Supplement to the SFP CSA

Reason for Request

  • New fuel assembly design will be used at MPS3
  • Gadolinia will be used as the burnable poison
  • Depletion credit in the CSA assumes a different burnable poison type
  • CSA does not justify that gadolinia is bounded September 7, 2022 6

MPS3 - Supplement to the SFP CSA Proposed Resolution

  • Submit a supplement to the current MPS3 CSA to the NRC
  • Justify through previous work that the use of gadolinia BP is bounded by the current CSAs burnup credit analysis
  • Demonstrate the previous works applicability to MPS3
  • Scope:
  • No Technical Specifications are being changed
  • No credit is being taken for gadolinia in fresh fuel
  • No calculations are being updated or added to the current CSA
  • Only change is to extend the burnup credits bounds of applicability September 7, 2022 7

MPS3 - Supplement to the SFP CSA Proposed Justification for Submittal

  • Discussion of the NRC endorsed guidance in RG 1.240
  • NEI 12-16 states modeling no gadolinia is conservative during depletion
  • These reports investigated the effects of gadolinia on burnup credit and determined its use to be conservative
  • DENC will demonstrate that these findings are applicable to MPS3 (Satisfying the RG 1.240, C.1.p clarification)

September 7, 2022 8

MPS3 - Supplement to the SFP CSA Proposed Justification for Submittal (cont.)

  • Discussion of previous utility submittals with gadolinia work
  • Prairie Island (2013) and Millstone Unit 2 (2016) submittals investigated the effects of gadolinia on burnup credit and determined its use to be conservative
  • DENC will demonstrate that these findings are applicable to MPS3
  • The CSA normal and accident scenarios will remain conservative September 7, 2022 9

MPS3 - Supplement to the SFP CSA Proposed Justification for Submittal (cont.)

  • No changes to current Technical Specifications
  • New Fuel Storage Area takes no BP credit
  • Region 1A - high enrichment, low burnup, gadolinia cannot be used
  • SFP burnup credit applicability extended to include gadolinia BP September 7, 2022 10 Unused with gadolinia fuel Burnup requirements apply to gadolinia fuel

MPS3 - Supplement to the SFP CSA Submittal Conclusion

  • Industry guidance reports demonstrated that gadolinia can conservatively be unmodeled in the depletion analysis
  • Supplement will demonstrate applicability to MPS3
  • Utility submittals demonstrated that gadolinia can conservatively be unmodeled in the depletion analysis
  • Supplement will demonstrate applicability to MPS3
  • Therefore, the depletion analysis in the current MPS3 SFP CSA bounds the effects associated with the use of gadolinia BP September 7, 2022 11

MPS3 - Supplement to the SFP CSA Schedule

  • Submittal date is targeted for 4Q2022
  • NRC approval will be requested 12 months after submittal
  • Supports implementation by 3R23 (spring 2025) outage
  • If this supplement is approved, DENC would consider these items as the licensing basis for MPS3 SFP criticality:

Approved SFP CSA in 2019, including RAIs and SE Approved 2022 CSA Supplement September 7, 2022 12

Questions?

MPS3 - Supplement to the SFP CSA September 7, 2022 13

MPS3 - Supplement to the SFP CSA References MPS3 Licensing Basis Letter to NRC, Millstone, Unit 3, License Amendment Request Regarding Proposed Technical Specifications Changes for Spent Fuel Storage and New Fuel Storage, 05/03/2018 (NRC ADAMS Accession Number ML18128A049).

Letter from NRC to DENC, Millstone Power Station, Unit No. 3 - Issuance of Amendment No. 273 Regarding Technical Specification Changes for Spent Fuel Storage and New Fuel Storage (EPID L-2018-LLA-0126), 05/28/2019 (NRC ADAMS Accession Number ML19126A000).

Industry Guidance NEI 12-16, Revision 3, "Guidance for Performing Criticality Analyses of Fuel Storage at Light-Water Reactor Power Plants, 03/31/2018 (NRC ADAMS Accession Number ML18088B400).

NEI 12-16, Revision 4, Guidance for Performing Criticality Analyses of Fuel Storage at Light-Water Reactor Power Plants, 09/30/2019 (NRC ADAMS Accession Number ML19269E069).

NUREG/CR-6760, "Study of the Effect of Integral Burnable Absorbers for PWR Burnup Credit" 03/31/2002 (NRC ADAMS Accession Number ML020770436).

EPRI 3002008197 Sensitivity Analyses for Spent Fuel Pool Criticality - Revision 1 (NRC ADAMS Accession Number ML18088B399).

Regulatory Guide RG 1.240, Fresh and Spent Fuel Pool Criticality Analyses, 03/31/2021 (NRC ADAMS Accession Number ML20356A127).

Utility SEs Letter from NRC to VEPCO, North Anna Power Station, Unit Nos. 1 and 2 - Issuance of Amendments to Revise Technical Specifications Regarding New and Spent Fuel Storage (CAC NOS. MF9712 AND MF9713, EPID L-2017-LLA-0240), 07/27/2018 (NRC ADAMS Accession Number ML18180A197).

Letter from NRC to Prairie Island, Prairie Island Nuclear Generating Plant, Units 1 and 2 - Issuance of Amendments re: Spent Fuel Pool Criticality Changes, 08/29/2013 (NRC ADAMS Accession Number ML13241A383).

Letter from NRC to DENC, Millstone Power Station, Unit 2 - Issuance of Amendment No. 327 Re: Proposed Technical Specification Changes for Spent Fuel Storage (CAC No. MF0435), 06/23/2016 (NRC ADAMS Accession Number ML16003A008).

September 7, 2022 14

MPS3 - Supplement to the SFP CSA Acronyms

  • BP - Burnable Poison
  • CFR - Code of Federal Regulations
  • CSA - Criticality Safety Analysis
  • EPRI - Electric Power Research Institute
  • IFBA - Integral Fuel Burnable Absorber
  • MPS3 - Millstone Power Station Unit 3
  • NEI - Nuclear Energy Institute
  • NRC - Nuclear Regulatory Commission
  • RAI - Request for Addition Information
  • RG - Regulatory Guide
  • SE - Safety Evaluation
  • SFP - Spent Fuel Pool
  • WABA - Wet Annular Burnable Absorber September 7, 2022 15
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