SBK-L-15195, Best Estimate Large Break Loss of Coolant Accident 10 CFR 50.46 30-Day Report

Best Estimate Large Break Loss of Coolant Accident 10 CFR 50.46 30-Day Report

ML15317A008
Person / Time
Site:	Seabrook
Issue date:	11/07/2015
From:	Ossing M NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-15195
Download: ML15317A008 (4)

Text

ENERGY_

SEABROOK November 7, 2015 10 CFR 50.46 Docket No. 50-443 SBK-L-15 195 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Seabrook Station Best Estimate Large Break Loss of Coolant Accident 10 CFR 50.46 30-Day Report

Reference:

NextEra Energy Seabrook, LLC letter SBK-L- 15140, "Annual Report of Changes to, or Errors in Emergency Core Cooling System Models or Applications,"

July 9, 2015 In accordance with the requirements of 10 CFR 50.46(a)(3)(ii), NextEra Energy Seabrook, LLC (NextEra) submits an annual tabulation of the current Large Break Loss of Coolant Accident (LBLOCA) and Small Break Loss of Coolant Accident (SBLOCA) Peak Clad Temperature (PCT) margin utilization tables applicable to Seabrook Station. The referenced letter documented the 2014 Annual Report of PCT for the SBLOCA and LBLOCA for Seabrook Station. .The reported LBLOCA PCT and cumulative change were 1939 0F and 155 0F respectively.

10 CFR 50.46(a)(3)(ii) also requires that changes to the BE LBLOCA Evaluation Model (EM) and small break LOCA EM resulting in cumulative changes and errors such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50 0 F be reported to the NRC within 30 days. This 30-day report documents changes and errors in the Seabrook BE LBLOCA analysis.

The enclosure provides the new BE LBLOCA PCT rackup for Seabrook Station that accounts for the changes and errors. The BE LBLOCA predicted values for the PCT and the cumulative change are 1939 0 F and 155 0 F, respectively. These values are unchanged from those provided in the referenced letter. 4o0o2 NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

U. S. Nuclear Regulatory Commission SBK-L-15 195 / Page 2 10 CFR 50.46(a)(3)(ii) also requires that a schedule for reanalysis be provided or compliance with the requirements of the regulation be shown. Continued compliance with 10 CFR 50.46 requirements is demonstrated by the total estimated PCT value of 1939 0F remaining well below the limit of 2200 0F.

Should you have any questions regarding this report, please contact me at (603) 773-7512.

Sincerely, NextEra Energy Seabrook, LLC cc: D. Dorman, NRC Region I Administrator J. Lamb, NRC Project Manager, Proj ect Directorate I-2 P. Cataldo, NRC Senior Resident Inspector

ENCLOSURE TO SBK-L-15195

<p Seabrook 10 CFR 50.46 30-Day Report for BE LBLOCA PCT Peak Cladding Cumulative BE LBLOCA Temperature Charnre 2014 10 CFR 50.46 (1) 1939 OF 155 OF Changes / Errors

- Modeling errors in the lower support plate, 0 OF 0OF core barrel, and vessel cladding unheated conductors (2) 10 CFR 50.46 30-Day Report 1939 OF 155 OF References

1. NextEra Energy letter, M. Ossing to U.S. Nuclear Regulatory Commission, "Seabrook Station Annual Report of Changes to, or Errors in Emergency Core Cooling System Models or Applications," SBK-L-15 140, July 9, 2015.

2. Westinghouse letter, E. M. Malek to J. Perryman, "NextEra Energy Seabrook Station 10 CFR 50.46 Report for Lower Support Plant, Core Barrel, and Vessel Wall Unheated Conductor Errors,," NF-NEXT- 15-243, October 19, 2015.

ENERGY_

SEABROOK November 7, 2015 10 CFR 50.46 Docket No. 50-443 SBK-L-15 195 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Seabrook Station Best Estimate Large Break Loss of Coolant Accident 10 CFR 50.46 30-Day Report

Reference:

NextEra Energy Seabrook, LLC letter SBK-L- 15140, "Annual Report of Changes to, or Errors in Emergency Core Cooling System Models or Applications,"

July 9, 2015 In accordance with the requirements of 10 CFR 50.46(a)(3)(ii), NextEra Energy Seabrook, LLC (NextEra) submits an annual tabulation of the current Large Break Loss of Coolant Accident (LBLOCA) and Small Break Loss of Coolant Accident (SBLOCA) Peak Clad Temperature (PCT) margin utilization tables applicable to Seabrook Station. The referenced letter documented the 2014 Annual Report of PCT for the SBLOCA and LBLOCA for Seabrook Station. .The reported LBLOCA PCT and cumulative change were 1939 0F and 155 0F respectively.

10 CFR 50.46(a)(3)(ii) also requires that changes to the BE LBLOCA Evaluation Model (EM) and small break LOCA EM resulting in cumulative changes and errors such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50 0 F be reported to the NRC within 30 days. This 30-day report documents changes and errors in the Seabrook BE LBLOCA analysis.

The enclosure provides the new BE LBLOCA PCT rackup for Seabrook Station that accounts for the changes and errors. The BE LBLOCA predicted values for the PCT and the cumulative change are 1939 0 F and 155 0 F, respectively. These values are unchanged from those provided in the referenced letter. 4o0o2 NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

U. S. Nuclear Regulatory Commission SBK-L-15 195 / Page 2 10 CFR 50.46(a)(3)(ii) also requires that a schedule for reanalysis be provided or compliance with the requirements of the regulation be shown. Continued compliance with 10 CFR 50.46 requirements is demonstrated by the total estimated PCT value of 1939 0F remaining well below the limit of 2200 0F.

Should you have any questions regarding this report, please contact me at (603) 773-7512.

Sincerely, NextEra Energy Seabrook, LLC cc: D. Dorman, NRC Region I Administrator J. Lamb, NRC Project Manager, Proj ect Directorate I-2 P. Cataldo, NRC Senior Resident Inspector

ENCLOSURE TO SBK-L-15195

<p Seabrook 10 CFR 50.46 30-Day Report for BE LBLOCA PCT Peak Cladding Cumulative BE LBLOCA Temperature Charnre 2014 10 CFR 50.46 (1) 1939 OF 155 OF Changes / Errors

- Modeling errors in the lower support plate, 0 OF 0OF core barrel, and vessel cladding unheated conductors (2) 10 CFR 50.46 30-Day Report 1939 OF 155 OF References

1. NextEra Energy letter, M. Ossing to U.S. Nuclear Regulatory Commission, "Seabrook Station Annual Report of Changes to, or Errors in Emergency Core Cooling System Models or Applications," SBK-L-15 140, July 9, 2015.

2. Westinghouse letter, E. M. Malek to J. Perryman, "NextEra Energy Seabrook Station 10 CFR 50.46 Report for Lower Support Plant, Core Barrel, and Vessel Wall Unheated Conductor Errors,," NF-NEXT- 15-243, October 19, 2015.