CNL-24-036, – 10 CFR 50.46 Annual Report

– 10 CFR 50.46 Annual Report

ML24116A027
Person / Time
Site:	Browns Ferry
Issue date:	04/25/2024
From:	Sivaraman M Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CNL-24-036
Download: ML24116A027 (1)

Text

1101 Market Street, Chattanooga, Tennessee 37402

CNL-24-036

April 25, 2024

10 CFR 50.46

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296

Subject:

Browns Ferry Nuclear Plant, Units 1, 2, and 3 - 10 CFR 50.46 Annual Report

References:

1. TVA letter to NRC, CNL-23-034, "Browns Ferry Nuclear Plant, Units 1, 2, and 3 - 10 CFR 50.46 Annual Report, dated April 26, 2023 (ML23116A290)

2. NRC letter to TVA, "Browns Ferry Nuclear Plant, Units 1, 2, and 3 - Issuance of Amendment Nos. 325, 348, and 308 Regarding Application of Advanced Framatome Methodologies, and Adoption of TSTF-564-A, Revision 2, 'Safety Limit MCPR,' in Support of ATRIUM 11 Fuel Use (EPID L-2021-LLA-0132),"

dated January 13, 2023 (ML22348A066)

The purpose of this letter is to provide the annual report, as required by Title 10 of the Code of Federal Regulations (10 CFR) 50.46, of changes or errors discovered in the emergency core cooling system evaluation model for Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3.

Since the previous submittal of an annual report (Reference 1), Unit 3 has now implemented the first reload of ATRIUM' 11 fuel as approved per Reference 2.

This submittal satisfies the annual reporting requirement of 10 CFR 50.46(a)(3)(ii) for BFN Units 1, 2, and 3.

As presented in this report, BFN compliance with 10 CFR 50.46 requirements is demonstrated by the changes to the evaluation models resulting in no change to the calculated peak cladding temperature (PCT) for all three units. No errors were discovered, and PCT remains below the 2200 degrees Fahrenheit limit. Therefore, Tennessee Valley Authority has concluded that no proposed schedule for providing a reanalysis or other action is required.

U. S. Nuclear Regulatory Commission CNL-24-036 Page 2 April 25, 2024

There are no new regulatory commitments associated with this submittal. Please address any questions to David Renn, Manager, Site Licensing, at djrenn@tva.gov.

Respectfully,

Manu Sivaraman Site Vice President Browns Ferry Nuclear Plant

Enclosure:

10 CFR 50.46 Annual Report for BFN Units 1, 2, and 3

cc (Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant

Enclosure

10 CFR 50.46 ANNUAL REPORT FOR BROWNS FERRY NUCLEAR PLANT, UNIT 1

The Browns Ferry Nuclear Plant (BFN), Unit 1 core contains the ATRIUM TM 10XM fuel designs.

The previous Title 10 of the Code of Federal Regulations (10 CFR) 50.46 annual report for BFN was submitted per Reference 1.

Fuel Evaluation

Table 1 details the accumulated peak cladding temperature (PCT) impact due to errors and changes in the loss of coolant accident analysis since the previously reported analysis of record (AOR) (Reference 1). PCT analysis was previously re-baselined per Reference 2.

Table 1: Cumulative Effect of PCT Changes - BFN Unit 1 (ATRIUM 10XM)

Baseline PCT (Reference 2) 2052°F

All thermal conductivity degradation effects (Reference 2, Section 5.1) + 0°F Increased Access Hole Cover and low pressure coolant injection (LPCI) + 0°F Leakages (Reference 3)

RDX2_2_RDX4 Corrections (Reference 3) + 0°F RODEX4 Pellet Rim Porosity Model (Reference 3) + 0°F New licensing PCT 2052°F

Absolute value of accumulated changes since last baseline analysis 0°F

References (Unit 1)

1. TVA letter to NRC, CNL-23-034, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

10 CFR 50.46 Annual Report, dated April 26, 2023 (ML23116A290)

2. Framatome Inc., ANP-3547P, Revision 2, Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM 10XM Fuel (EPU MELLLA+), dated January 2020

3. Framatome Inc., FS1-0044279, Revision 5, 10 CFR 50.46 PCT Error Report for Browns Ferry Units 1, 2, and 3 with EPU / MELLLA+ Conditions, dated October 13, 2023

CNL-24-036 E1 of 5 Enclosure

10 CFR 50.46 ANNUAL REPORT FOR BROWNS FERRY NUCLEAR PLANT, UNIT 2

The BFN Unit 2 core contains the ATRIUM 10XM and ATRIUM 11 fuel designs. The previous 10 CFR 50.46 Annual Report for BFN was submitted per Reference 1.

Fuel Evaluation

Tables 2 and 3 detail the accumulated PCT impact due to errors and changes in the loss of coolant accident analysis since the previously reported AOR (References 1 and 4).

Table 2: Cumulative Effect of PCT Changes - BFN Unit 2 (ATRIUM 11)

Baseline PCT (Reference 4) 1898°F

S-RELAP5 Cladding Thermal Conductivity (Reference 5) + 0°F Cladding Hydrogen Content (Reference 5) + 0°F Cladding Oxide Thickness (Reference 5) + 0°F MICROBURN-B2 Provides Inappropriate Flow in Inlet Node for ACE + 0°F Calculations (Reference 5)

Increased Access Hole Cover and LPCI Leakages (Reference 5) + 0°F RODEX4 Pellet Rim Porosity Model (Reference 5) + 0°F New licensing PCT 1898°F

Absolute value of accumulated changes 0°F

Table 3: Cumulative Effect of PCT Changes - BFN Unit 2 (ATRIUM 10XM)

Baseline PCT (Reference 2) 2052°F

All thermal conductivity degradation effects (Reference 2, Section 5.1) + 0°F Access Hole Cover and LPCI Leakages (Reference 3) + 0°F RDX2_2_RDX4 Corrections (Reference 3) + 0°F RODEX4 Pellet Rim Porosity Model (Reference 3) + 0°F

New licensing PCT 2052°F

Absolute value of accumulated changes since last baseline analysis 0°F

CNL-24-036 E2 of 5 Enclosure

References (Unit 2)

1. TVA letter to NRC, CNL-23-034, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

10 CFR 50.46 Annual Report, dated April 26, 2023 (ML23116A290)

2. Framatome Inc., ANP-3547P, Revision 2, Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM 10XM Fuel (EPU MELLLA+), dated January 2020

3. Framatome Inc., FS1-0044279, Revision 5, 10 CFR 50.46 PCT Error Report for Browns Ferry Units 1, 2, and 3 with EPU / MELLLA+ Conditions, dated October 13, 2023

4. Framatome Inc., ANP-3905P, Revision 2, Browns Ferry Units 1, 2, and 3 LOCA Analysis for ATRIUM 11 Fuel, dated June 2022

5. Framatome Inc., FS1-0063865, Revision 3, 10 CFR 50.46 PCT Error Report for Browns Ferry Units 1, 2, and 3 ATRIUM 11 Fuel, dated October 13, 2023

CNL-24-036 E3 of 5 Enclosure

10 CFR 50.46 ANNUAL REPORT FOR BROWNS FERRY NUCLEAR PLANT, UNIT 3

The BFN Unit 3 core contains the ATRIUM 10XM and ATRIUM 11 fuel designs. The previous 10 CFR 50.46 Annual Report for BFN was submitted per Reference 1. Since the issuance of References 1 and 4, Unit 3 has begun operation with ATRIUM 11 fuel.

Fuel Evaluation

Tables 4 and 5 detail the accumulated PCT impact due to errors and changes in the loss of coolant accident analysis since the previously reported AOR (References 1 and 4).

Table 4: Cumulative Effect of PCT Changes - BFN Unit 3 (ATRIUM 11)

Baseline PCT (Reference 4) 1898°F

S-RELAP5 Cladding Thermal Conductivity (Reference 5) + 0°F Cladding Hydrogen Content (Reference 5) + 0°F Cladding Oxide Thickness (Reference 5) + 0°F MICROBURN-B2 Provides Inappropriate Flow in Inlet Node for ACE + 0°F Calculations (Reference 5)

Increased Access Hole Cover and LPCI Leakages (Reference 5) + 0°F RODEX4 Pellet Rim Porosity Model (Reference 5) + 0°F New licensing PCT 1898°F

Absolute value of accumulated changes 0°F

Table 5: Cumulative Effect of PCT Changes - BFN Unit 3 (ATRIUM 10XM)

Baseline PCT (Reference 2) 2052°F

All thermal conductivity degradation effects (Reference 2, Section 5.1) + 0°F Increased Access Hole Cover and LPCI Leakage. (Reference 3) + 0°F RDX2_2_RDX4 Corrections (Reference 3) + 0°F RODEX4 Pellet Rim Porosity Model (Reference 3) + 0°F

New licensing PCT 2052°F

Absolute value of accumulated changes since last baseline analysis 0°F

CNL-24-036 E4 of 5 Enclosure

References (Unit 3)

1. TVA letter to NRC, CNL-23-034, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

10 CFR 50.46 Annual Report, dated April 26, 2023 (ML23116A290)

2. Framatome Inc., ANP-3547P, Revision 2, Browns Ferry Units 1, 2, and 3 LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM 10XM Fuel (EPU MELLLA+), dated January 2020

3. Framatome Inc., FS1-0044279, Revision 5, 10 CFR 50.46 PCT Error Report for Browns Ferry Units 1, 2, and 3 with EPU / MELLLA+ Conditions, dated October 13, 2023

4. Framatome Inc., ANP-3905P, Revision 2, Browns Ferry Units 1, 2, and 3 LOCA Analysis for ATRIUM 11 Fuel, dated June 2022

5. Framatome Inc., FS1-0063865, Revision 3, 10 CFR 50.46 PCT Error Report for Browns Ferry Units 1, 2, and 3 ATRIUM 11 Fuel, dated October 13, 2023

CNL-24-036 E5 of 5