ML18312A350

Meeting to Discuss Proposed Technical Specification Changes Needed of Associated with the Use of Westinghouse Robust Fuel Assemblies at Sequoyah Nuclear Plant Units 1 & 2 - November 14, 2018

ML18312A350
Person / Time
Site:	Sequoyah
Issue date:	11/14/2018
From:	Andrew Hon Plant Licensing Branch II
To:	James Shea Tennessee Valley Authority
Hon A DORL/LPL2-2 301-415-8480
References
Download: ML18312A350 (14)

Text

Meeting to Discuss Proposed Technical Specification Changes Needed or Associated with the Use of Westinghouse Robust Fuel Assemblies at Sequoyah Nuclear Plant Units 1 & 2 November 14, 2018

Agenda

• Introductions

• Purpose

• Requested Technical Specification (TS) changes

• Content of recent fuel transition license amendment requests (LARs)

• Approach for the Sequoyah Nuclear Plant (SQN) LAR

• Analysis approach for the Framatome HTPTM fuel

• Schedule

• Summary

• NRC feedback l 2

Purpose

• Present the proposed approach for a LAR to transition from Framatome HTPTM fuel assemblies to Westinghouse Electric Company (WEC) RFA-2 fuel at SQN Units 1 and 2

• TVA is proposing a more efficient approach than has been used in previous fuel transition LARs

• Solicit NRC feedback on the proposed approach l 3

Requested TS Changes

• Add Optimized ZIRLOTM to the approved fuel clad materials

• Move the Core Safety Limits and the constants used in the Over Temperature T and Over Power T trip setpoints to the COLR

• Revise the Departure from Nucleate Boiling Ratio (DNBR) limit to specify DNBR limits will be maintained greater than or equal to the 95/95 DNBR criterion for the DNB correlations used to establish core operating limits Optimized ZIRLO is a trademark or registered trademark of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.

l 4

Requested TS Changes (continued)

• Revise the fuel centerline temperature limit to specify temperatures will be maintained less than the fuel centerline melt temperature limit determined by the approved fuel rod design methodology

• Make the requirement for end of core life (EOL) moderator temperature coefficient (MTC) measurement conditional on core parameters

• Revise the power distribution limits to be consistent with WEC methodology and Standard TS

• Add approved WEC methodologies to the COLR methodologies list l 5

Content of Recent Fuel Transition LARs

• Description of Fuel Assembly

• Operating Experience

• Debris Filter Design

• Representative Core Designs

• Thermal-Hydraulic Compatibility Discussion

• Transition Core DNB Evaluation

• Mechanical Evaluation

• Loss of Coolant Accident (LOCA) Analysis

• Disposition of Non-LOCA Events

• Fuel Source Term(s) Evaluation l 6

Approach for the SQN LAR

• LAR will only discuss the requested TS changes

• Analyses will be performed using approved methods and will meet all applicable acceptance criteria consistent with the current SQN licensing basis

• WEC has demonstrated success with their methodologies to be used in the fuel transition

• The analyses required to implement RFA-2 will be adopted under 10 CFR 50.59 l 7

Analysis Approach for the HTPTM Fuel

• Framatome provided WEC with data regarding the HTPTM fuel and core designs

• WEC nuclear design methods will be used to model prior HTPTM cycles

- The power distribution information and corresponding peaking factors will be used to establish a design limit for the HTPTM fuel

- Because previous HTPTM peaking limits were developed using approved Framatome methods, limiting HTPTM peaking to that seen in previous HTPTM cores maintains conformance with those methods l 8

Analysis Approach for the HTPTM Fuel (continued)

• The COLR limit for FQ(Z) will be unchanged from the current limit for the HTPTM fuel

• The FNH COLR limit will be set separately for RFA-2 and HTPTM fuel

• The HTPTM fuel will be monitored to a lower limit

• HTPTM fuel rod mechanical design and fuel performance will be confirmed by ensuring operation within the previously established acceptable operating envelope l 9

Analysis Approach for the HTPTM Fuel (continued)

• Sufficient information has been obtained from Framatome to assess the HTPTM fuel using WEC methods for the following analyses:

- Thermal-Hydraulic behavior and compatibility

- Non-LOCA safety analyses will use PAD5 generated fuel temperatures to assess HTPTM

- LOCA analysis including transition core effects

- Seismic/LOCA grid crush

• Transition core DNBR penalty for the HTPTM fuel is determined by approved WEC transition core methodology and conservative assumptions on the HTPTM l 10

Schedule

• SQN plans to load WEC RFA-2 fuel in the fall of 2022

• Pre-submittal meeting at NRC in February 2019

• TVA will submit the as proposed LAR in April 2019

• While not required to support the LAR, analyses and evaluations of a representative core design are scheduled to be completed by October 2019

• In order to proceed with confidence with the transition to RFA-2, TVA requests LAR approval by June 2020 l 11

Summary

• SQN plans to load WEC RFA-2 fuel in the fall of 2022

• TVA has evaluated the transition to RFA-2 and believes only the TS changes require prior NRC approval in accordance with10 CFR 50.59

• Analyses will be performed using approved methods and will meet applicable acceptance criteria consistent with the current SQN licensing basis

• TVA proposes to submit only the TS changes needed to support the fuel transition l 12

NRC Feedback l 13