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
| 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 FirstEnergy Nuclear Operating Company Barry S. Allen Vice President - Nuclear May 27,2011 L-11-167 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 5501 North State Route 2 Oak Harbor, Ohio 43449 419-321-7676 Fax: 419-321-7582 10 CFR 50.46(a)(3)(ii) 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 Utility Name:
FirstEnergy Mk-B10M LBLOCA Mk-B10K LBLOCA Mk-B12 LBLOCA Mk-B-HTP LBLOCA Mixed-Core Mk-B-HTP LBLOCA Full-Core SBLOCA Item Reporting Category Description PCT or (Delta PCT)
Licensing Basis at Beginning of 2010
<2,102 oF Estimated EM R0.61 2,102 oF Analyzed EM R0.61 2,099 oF Analyzed EM R0.61 2,098 oF 2 Estimated EM R0.91 N/A 1,555 oF Analyzed EM R0.91 2010 Licensing Activity 1
EM Error EOC SBLOCA Axial Power Shape (AREVA CR 2010-4150)
N/A N/A N/A N/A N/A
+225 oF 2
Application Change Implemented Full Core Mk-B-HTP during 16RFO for the 17th operating cycle. 2 N/A N/A N/A N/A 2,119 oF 2 Estimated EM R0.91 N/A Licensing Basis at End of 2010 N/A N/A N/A N/A 2,119 oF 2 Estimated EM R0.91 1,780 oF Analyzed 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.