L-11-167, CFR 50.46 Report of Changes or Errors in ECCS Evaluation Models, for the Period of January 1, 2010 to December 31, 2010

CFR 50.46 Report of Changes or Errors in ECCS Evaluation Models, for the Period of January 1, 2010 to December 31, 2010

ML111510642
Person / Time
Site:	Davis Besse
Issue date:	05/27/2011
From:	Allen B FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-11-167
Download: ML111510642 (3)

Text

FENOC 5501 North State Route 2 FirstEnergy Nuclear Operating Company Oak Harbor, Ohio 43449 Barry S. Allen 419-321-7676 Vice President - Nuclear Fax: 419-321-7582 May 27,2011 L-11-167 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 10 CFR 50.46 Report of Changes or Errors in ECCS Evaluation Models In accordance with 10 CFR 50.46(a)(3)(ii), FirstEnergy Nuclear Operating Company (FENOC) hereby submits the annual report for changes and errors in the emergency core cooling system (ECCS) evaluation model (EM) and in the application of the model used at the Davis-Besse Nuclear Power Station, Unit NO.1. The attached report covers the period of January 1, 2010 to December 31, 2010.

There are no regulatory commitments contained in this letter. If there are any questions or if additional information is required, please contact Mr. Thomas A. Lentz, Manager-Fleet Licensing, at (330) 761-6071.

Sincerely, l<wlJr :fo. B. All ....

Barry S. Allen

Attachment:

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

Attachment L-11-167 Annual Report of Changes to the 10 CFR 50.46 Emergency Core Cooling System Evaluation Model and in the Application of the Model for the Davis-Besse Nuclear Power Station, Unit No. 1 Page 1 of 2 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 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).

EVALUATION MODEL CHANGES AND ERRORS Babcock & Wilcox Nuclear Technologies (BWNT) Loss of Coolant Accident (LOCA)

Evaluation Model AREVA NP, Inc. (AREVA) identified that the small break LOCA (SBLOCA) Axial Power Shape defined in BAW-10192P-A, Revision 0, BWNT LOCA - BWNT Loss-of-Coolant Accident Evaluation Model for Once-Through Steam Generator Plants, may not be bounding for middle-of-cycle to end-of-cycle (MOC to EOC) conditions. A new estimated SBLOCA PCT of 1780°F was assigned to the Davis-Besse Nuclear Power Station, Unit No. 1. This PCT represented an increase of 225°F from the previously reported SBLOCA. The error correction was limited to SBLOCA applications; therefore, the PCT for large break LOCA (LBLOCA) was unaffected. FENOC notified the NRC of the significant change to the SBLOCA by letter dated September 2, 2010 with additional information provided by letter dated December 17, 2010.

CRAFT2 LOCA Evaluation Models No errors were identified and no changes were implemented during the reporting period.

EVALUATION MODEL APPLICATION CHANGES AND ERRORS No errors were identified.

One application change occurred when a full core of Mark (Mk)-B-HTP fuel was loaded.

This resulted in a full core Mk-B-HTP PCT of 2119°F. The change resulted in a cumulative LBLOCA PCT increase of 21°F over the mixed core Mk-B-HTP PCT, which was estimated to be 2098°F.

SUMMARY

A summary of the PCTs at the end of the reporting period are provided in Table 1.

Attachment L-11-167 Page 2 of 2 Table 1 10 CFR 50.46 Summary for 2010 Plant Name: Davis-Besse Unit 1 LOCA Spectrum Mk-B-HTP Mk-B-HTP Mk-B10M Mk-B10K Mk-B12 LBLOCA Utility Name: FirstEnergy LBLOCA SBLOCA LBLOCA LBLOCA LBLOCA Mixed-Full-Core Core Item Reporting Description PCT or (Delta PCT)

1. Category

<2,102 oF 2,102 oF 2,099 oF 2,098 oF 2 1,555 oF Licensing Basis at Beginning of 2010 Estimated Analyzed Analyzed Estimated N/A Analyzed 1 1 1 1 1 EM R0.6 EM R0.6 EM R0.6 EM R0.9 EM R0.9 2010 Licensing Activity EOC SBLOCA Axial Power Shape 1 EM Error N/A N/A N/A N/A N/A +225 oF (AREVA CR 2010-4150) 2,119 oF 2 Application Implemented Full Core Mk-B-HTP during 16RFO for 2 N/A N/A N/A N/A Estimated N/A Change the 17th operating cycle. 2 1 EM R0.9 2,119 oF 2 1,780 oF Licensing Basis at End of 2010 N/A N/A N/A N/A Estimated Analyzed 1

EM R0.9 EM R0.91 Footnotes:

(1) Evaluation Model revision number.

(2) The reactor operated with a mixed core of Mk-B-HTP fuel through the 16th operating cycle, which ended in 2010. The reactor then began operation in the 17th cycle with a full core of Mk-B-HTP fuel.