ML19178A246
| ML19178A246 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 07/01/2019 |
| From: | Tennessee Valley Authority |
| To: | Plant Licensing Branch II |
| Jordan N 415-7410 | |
| References | |
| Download: ML19178A246 (13) | |
Text
Watts Bar Nuclear Plant (WBN)
Meeting on the Proposed License Amendment Request to Implement FULL SPECTRUMTM Loss of Coolant Accident (FSLOCATM) Evaluation Methodology and Eliminate TPBAR Post-LOCA Failure Assumptions July 1, 2019 FULL SPECTRUM and FSLOCA are trademarks 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.
Opening Remarks Overview of the License Amendment Request (LAR)
Technical Specification Changes Regulatory Precedents Break (end of Open Portion of the Meeting)
LAR Technical Evaluation Content (Closed)
Technical Evaluation Technical Evaluation Results Closing Remarks Agenda l 2
Opening Remarks
- Incorporates FSLOCATM Methodology for 10 CFR 50.46 compliance
- Implements new tritium-producing burnable absorber rods (TPBAR) stress analysis methodology to assess TPBAR rupture following large-break LOCA l 3
Overview of the LAR Reason for Change Implement FSLOCA methodology to resolve licensing issues with PAD4TCD (note: WBN Unit 2 currently has a license condition that permits use of PAD4TCD until the WBN Unit 2 steam generators are replaced)
Use lower peak cladding temperatures (PCT) from FSLOCA methodology predictions as part of new TPBAR stress analysis methodology to demonstrate that TPBAR integrity is maintained during a large break loss-of-coolant-accident (LBLOCA) event Allows TVA to change the post-LOCA criticality assumption of TPBAR rupture and its consequent effect of lithium loss (positive reactivity)
Allows TVA to simplify the core design, increase tritium production capability, and improve fuel economics l 4
Technical Specification Changes Proposed WBN Technical Specification (TS) changes:
TS 4.2.1, "Fuel Assemblies" (Unit 1 only) - Deletes Zircalloy clad description based on applicability of FSLOCA methodology TS 5.9.5, Core Operating Limits Report (WBN Units 1 and 2) -
Replaces WCAP-12945-P-A (Best Estimate LOCA Methodology) and WCAP-11054-P-A (NOTRUMP SBLOCA Methodology) with WCAP-16996-P-A (FSLOCA Methodology)
Proposed Revision to WBN 2 Operating License Condition 2.C(4) regarding implementation of this LAR (similar to PAD4TCD)
Various TS Bases changes also being provided in the LAR l 5
Proposed Change for WBN Unit 1 TS 4.2.1 l 6
Proposed Change for WBN Unit 1 TS 5.9.5 l 7
Proposed Change for WBN Unit 2 TS 5.9.5 l 8
Proposed Change for WBN Unit 2 OL 2.C(4) l 9
Regulatory Precedent FSLOCA is an approved large break and small break LOCA analysis methodology Diablo Canyon Nuclear Power Plant has submitted a LAR to use of the FSLOCA methodology (ML19003A196) and NRC audit in progress (ML19106A390)
Portion of the WBN LAR that discusses the LOCA analysis is similar in content to the Diablo Canyon FSLOCA methodology LAR There are no regulatory precedents for the TPBAR stress analysis l 10
Closing Remarks The FSLOCA methodology results along with the TPBAR stress analysis methodology support a change to the conservative assumption that TPBAR failure occurs as a result of a large break LOCA Removal of the TPBAR rupture assumptions allows for more efficient core designs, reduced fuel costs and increased tritium production at WBN TVA is submitting a LAR to remove the current license basis assumptions on TPBAR rupture and requesting approval of the LAR within 1 year of it being submitted.
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