ML21141A010

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La Salle County Station, Units 1 and 2, May 27, 2021 Pre Submission Public Meeting Slides (EPID-L-2021-LRM-0052)
ML21141A010
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 05/21/2021
From: Rhoades D
Exelon Generation Co, Exelon Nuclear
To:
NRC/NRR/DORL/LPL3
Vaidya B
References
EPID-L-2021-LRM-0052
Download: ML21141A010 (22)
v • d • e


Text

New Fuel Type and Vendor for LaSalle and Quad Cities NRC Pre-Submittal Meeting May 27, 2021

Agenda

  • Meeting Objectives
  • Project Purpose / Background Information
  • Overview of Proposed Licensing Amendment Requests (LARs)

- Criticality Safety Analysis Methodology Change (LaSalle, Quad Cities)

- Vendor Transition now using GNF Methods (Quad Cities)

- Improved Scram Speeds (Quad Cities)

  • Licensing Schedule and Outage Needs
  • Summary and Wrap-up 1

Meeting Objectives

  • Present information to NRC to enable a clear understanding of the overall projects and proposed site-specific LAR submittals
  • Obtain feedback from the NRC on the proposed LARs to ensure initial submittals address the full desired scope of topics and thus minimize the need for future RAIs
  • Mutual understanding of the proposed schedule and corresponding outage need date in order to ensure adequate NRC resource availability 2

Project Purpose/Background Information Exelon is transitioning all BWRs in the fleet (except NMP1) to GNFs latest fuel design, GNF3.

  • Plants currently licensed to GNF methods are covered under the 50.59 process.
  • Quad Cities is not currently licensed to GNF methods; thus, the vendor transition requires a LAR.

In conjunction with the fuel type change, there is a plan to change the criticality safety analysis methodology at LaSalle and Quad Cities.

The topical reports referenced in this presentation, except for GESTAR II, have not been previously approved by the NRC.

Planned LAR Submittals LaSalle:

1. Criticality Safety Analysis Methodology Change and Admin. Controls Update Quad Cities:
1. Criticality Safety Analysis Methodology Change
2. Vendor Transition now using GNF Methods
3. Improved Scram Speeds 3

Overview- CSA Methodology Change

Purpose:

Align criticality safety analysis (CSA) methodology with fuel vendor to optimize core design

- GNF performed criticality safety analysis for GNF3 fuel and a legacy bounding bundle per NEI 12-16 guidance

  • Planned changes in analysis methodology
  • New fuel vault is now covered through GESTAR II compliance for the GNF3 fuel 4

CSA Methodology Change and Admin. Controls Update -

LaSalle Spent Fuel Pool Criticality Safety Analysis (NEDC-33931P)

  • Utilize GNF methodology to analyze GNF3 fuel and bound all legacy fuel stored in LaSalles spent fuel pools New Fuel Vault Criticality Safety Analysis (NEDE-24011-P-A)
  • Utilize GESTAR II methodology for validating new fuel vault (NFV) criticality safety for GNF3 fuel stored in GE-designed NFV racks.

Technical Specification (TS) Section 4.3.1.1

LaSalle Proposed TS 4.3.1.1 Change 6

LaSalle Proposed TS 5.6.5.b Change 7

LaSalle Proposed TS 5.6.5.b Change (cont.)

8

CSA Methodology Change - Quad Cities Spent Fuel Pool Criticality Safety Analysis (NEDC-33932P)

  • Utilize GNF methodology to analyze GNF3 fuel and all legacy fuel stored in Quad Cities spent fuel pools New Fuel Vault Criticality Safety Analysis (NEDE-24011-P-A)
  • Revise TS 4.3.1.1.c to change the governing kinf limit structure according to the new CSA basis 9

Quad Cities Proposed TS 4.3.1.1 Change 10

Overview - Vendor Transition to GNF Methods at Quad Cities

Purpose:

Capture impacts due to change in reload fuel type that require NRC review.

- Exelon does not intend to submit mock reload results

  • Transition and equilibrium cycles will be crediting GESTAR II as the licensing basis for reloads that contain GNF3 fuel. No deviations from standard GNF methods will be taken.

- Technical Scope of LAR

  • GNF developed the GEXL98 critical power correlation for ATRIUM 10XM fuel
  • Exelon revised the AST calculations to incorporate the GNF3 fuel type
  • Dose consequence impacts
  • Environmental Qualification impacts
  • Framatome used RODEX2A + TCD penalties methodology to develop thermal-mechanical limits for ATRIUM 10XM fuel 11

Vendor Transition to GNF Methods at Quad Cities (contd)

GEXL98 Correlation (NEDC-33930P)

  • Quad Cities intends to use GNF methodologies to determine overall core operating limits for cycles containing GNF3 fuel. This change requires an additional analytical critical power (CP) correlation for analyzing the Framatome ATRIUM 10XM fuel with the GNF methodology.

- GEXL98 CP correlation uses the same functional form as previous GEXL correlations.

  • Total uncertainty in the GEXL98 correlation predictions for ATRIUM 10XM fuel is similar to the NRC-approved total uncertainty for GEXL96 correlation predictions for ATRIUM-9B fuel.

- Small extrapolations of the GEXL98 correlations range of application do not involve significant increase in the risk of boiling transition occurring for conditions in the extrapolated regions.

  • TS 5.6.5.b revised to incorporate new analytical method for developing core operating limits 12

Quad Cities Proposed TS 5.6.5.b Change 13

Vendor Transition to GNF Methods at Quad Cities (contd)

Revise AST post-LOCA Dose Analysis (QDC-0000-N-1481)

  • Input changes:

- All parameters, except those explicitly related to the core inventory, are identical to what was used in the previously submitted version of the AST post-LOCA dose consequence analysis (submitted March 31, 2020).

- The change in core inventory (due to GNF3 fuel introduction) resulted in an increase in post-LOCA dose consequences that remain within regulatory acceptance limits, but are considered a more than minimal increase

  • Methodology changes:

- None 14

Vendor Transition to GNF Methods at Quad Cities (contd)

RODEX2A + Thermal Conductivity Degradation Penalties (ANP-3918P)

  • In support of the legacy ATRIUM 10XM bundles during mixed core operation, Framatome provided thermal-mechanical limits for GNFs use based on calculations performed using a modified RODEX2A methodology.

- RODEX2A method previously approved by the NRC for use at Quad Cities is modified for the inclusion of thermal conductivity degradation (TCD) effects.

- TCD modification methodology previously shared with the NRC but was separate from the RODEX2A approval.

  • The RODEX2A fuel rod thermal-mechanical analysis code is used to analyze the fuel rod for fuel centerline temperature, cladding strain, rod internal pressure, cladding collapse, cladding fatigue and external oxidation.

15

Vendor Transition to GNF Methods at Quad Cities (contd)

Related Analyses Updates (50.59 scope)

  • Design Basis Core Inventories for Quad Cities GNF3 Equilibrium Core

- Calculation documents a bounding core inventory for Quad Cities Units 1 and 2 for GNF3 equilibrium core based on a combination of core average exposure and enrichment data

- Core inventory updated due to GNF3 fuel introduction

- Dose result increase remains within regulatory limits and meet minimal increase standard in 10 CFR 50.67

  • AST Fuel Handling Accident

- Core inventory updated due to GNF3 fuel introduction

- Dose results are bounded by the current licensing basis dose consequences

  • Environmental Qualification Impacts

- Core inventory updated due to GNF3 fuel introduction

- LAR will summarize impacts, if any, but EQ documentation will be updated separately 16

Overview- Improved Scram Speeds at Quad Cities

Purpose:

Revise control rod scram times to improve ASME overpressure limit margin

- Revised scram times based on actual scram time performance

- GNF performed an evaluation to characterize the impact of scram speed times on ASME dome pressure overpressure results. When previously under GNF methods, Quad Cities had little margin to the limit. The introduction of GNF3 fuel may further challenge that margin.

  • TS Table 3.1.4-1 revised with improved scram speed insertion times

- Plant operation should not be impacted 17

Quad Cities Proposed TS 3.1.4 Changes 18

Licensing Schedule and Outage Needs

  • Submit LARs according to schedule outlined below Plant/LAR LAR Submittal NRC Approval Implementation Need Date LaSalle/CSA July 2021 August 2022 November 2022 Quad Cities/CSA July 2021 August 2022 January 2023 Quad Cities/GNF3 September 2021 October 2022 January 2023 Transition Quad Cities/Scram December 2021 January 2023 March 2023 Speeds 19

Summary and Wrap-up Summary

  • Transition to GNF CSA methodology at LaSalle and Quad Cities:

- Improve core design efficiency by removing unnecessary conservatism due to vendor A CSA for vendor B fuel

- Simplify the design basis for CSAs for GNF fuel types

  • Spent fuel storage limits are more straightforward to confirm
  • New fuel storage is validated via GESTAR II compliance
  • Elimination of unused methodologies from LaSalle TS:

- Clarify the design basis by referencing GESTAR II only

  • GEXL98 CP correlation at Quad Cities:

- Allow GNF to utilize the critical power correlation for ATRIUM 10XM fuel during transition cycles licensed under GNF methods

  • RODEX2A with TCD penalties methodology at Quad Cities:

- Allow GNF to apply Framatome-developed thermal-mechanical limits to ATRIUM 10XM without modification during transition cycles licensed under GNF methods 20

Summary and Wrap-up Summary (cont.)

  • Revision of the AST post-LOCA calculation at Quad Cities:

- Allow GNF3 results to be implemented into the UFSAR/licensing basis

  • Improved scram times at Quad Cities:

- Ensure sufficient ASME overpressure analysis margin using GNF methods exists with the introduction of GNF3 fuel

- Have no expected impact on current plant performance Open Discussion 21

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