L-19-076, 2018 Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models and 10 CFR 50.46 30-Day Report

2018 Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models and 10 CFR 50.46 30-Day Report

ML19189A010
Person / Time
Site:	Davis Besse
Issue date:	07/08/2019
From:	Bezilla M FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-19-076
Download: ML19189A010 (4)

Text

FENOC 5501 North State Route 2 Oak Harbor, Ohio 43449 Mark B. Bezilla 419-321-7676 Vice President - Nuclear Fax: 419-321-7582 July 8, 2019 L-19-076 10 CFR 50.46(a)(3)(ii)

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

SUBJECT:

Davis-Besse Nuclear Power Station, Unit No. 1 Docket No. 50-346, License No. NPF-3 2018 Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models and 10 CFR 50.46 30-Day Report In accordance with 10 CFR 50.46(a)(3)(ii), FirstEnergy Nuclear Operating Company (FENOC) hereby submits the 2018 annual report of changes to or errors in an emergency core cooling system (ECCS) evaluation model, or in the application of such a model, for the Davis-Besse Nuclear Power Station (DBNPS), Unit No. 1. The attached report covers the period from January 1, 2018 to December 31, 2018 and notes the application of new evaluation models.

There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Mr. Phil H. Lashley, Acting Manager -

Nuclear Licensing and Regulatory Affairs, at (330) 315-6808.

jl;EJXJ if Mark B. Bezilla / '"

Attachment:

Annual Report of Changes to or Errors in the 10 CFR 50.46 Emergency Core Cooling System Evaluation Model, or in the Application of Such a Model, for the Davis-Besse Nuclear Power Station, Unit No. 1 cc: NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager Utility Radiological Safety Board

Attachment L-19-076 Annual Report of Changes to or Errors in the 10 CFR 50.46 Emergency Core Cooling System Evaluation Model, or in the Application of Such a Model, for the Davis-Besse Nuclear Power Station, Unit No. 1 Page 1 of 3 10 CFR 50.46(a)(3) states that each holder of an operating license shall report to the Nuclear Regulatory Commission (NRC), at least annually, each change to or error in an acceptable emergency core cooling system (ECCS) evaluation model (EM), or in the application of such a model, that affects the calculation of peak cladding temperature (PCT).

The nature of the change or error and its estimated effect on the limiting ECCS analysis is to be included in the report.

In the 2018 calendar year, there were no changes or errors associated with the evaluation model currently being used to support the design basis at Davis-Besse. This resulted in a 0 degrees Fahrenheit estimated change to the large break loss-of-coolant accident (LBLOCA) and small break loss-of-coolant accident (SBLOCA) PCT, as reported in Framatome letter dated May 30, 2019 (Reference 1).

Therefore, a net PCT change of 0°F (estimated) from the end of 2017 to the end of 2018 is reported for both LBLOCA and SBLOCA analyses.

The estimated effects on the peak cladding temperatures for this reporting period are summarized in Table 1.

References

1. Framatome Letter FS1-0043242-2.0, "Transmittal of Input for DBE 50.46 Report for 2018 (updated)." dated May 30, 2019.

Davis-Besse Nuclear Power Station, Unit No. 1 L-19-076 Page 2 of 3 Table 1 10 CFR 50.46 Summary for 2018 Plant Name: Davis-Besse Nuclear Power Station, Unit No. 1 LOCA Spectrum Mark-B-HTP LBLOCA Mark-B-HTP SBLOCA Licensee Name: FirstEnergy Nuclear Operating Company Full-Core Full-Core PCT or PCT Change (/!)

2,119°F 1,780°F Licensing Basis at Beginning of 2018 Estimated Estimated 2018 Licensing Activity Reporting Item# Description PCT or PCT Change (/!)

Category 1 EM Error None fl.:QOf fl.: QOf 2 EM Change None fl.: QOf fl.: QOf 2,119°F 1,780°F Licensing Basis at End of 2018 Estimated Estimated Notes:

1. Framatome completed a new LBLOCA analysis in accordance with NRC-approved methodology to address thermal conductivity degradation. The analysis was completed in July 2018 and formally transmitted to DBNPS in January 2019. FENOC implemented the new ECCS model on June 13, 2019. The results of the analysis depict a 41-degree Fahrenheit reduction in PCT, resulting in 2078 degrees Fahrenheit (analyzed).

Davis-Besse Nuclear Power Station, Unit No. 1 L-19-076 Page 3 of 3

2. Framatome completed a new SBLOCA analysis in accordance with NRG-approved methodology. The lower power level used resulted in a lower analyzed PCT. The analyses were completed in 2016 and formally transmitted to DBNPS. FENOC implemented the new ECCS model on June 13, 2019. The results of the analysis depict a 410-degree Fahrenheit reduction in PCT, resulting in 1370 degrees Fahrenheit (analyzed). The large PCT reduction is attributed primarily to the difference in analyzed power, from 3025 MWt analyzed for a power uprate that was not pursued, to 2827 MWt, the current operating power level including uncertainty.

3. Due to the timing of the 2018 annual report and the implementation of the new analysis in 2019, the updated model results are not captured in the above table but will appear in the next 10 CFR 50.46 Annual Report for DBNPS.