ML081840145

Annual Report on Westinghouse Electric Company LLC Combustion Engineering Emergency Core Cooling System Performance Evaluation Models

ML081840145
Person / Time
Site:	Waterford
Issue date:	06/30/2008
From:	Murillo R Entergy Nuclear South
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
W3F1-2008-0008
Download: ML081840145 (5)

Text

Entergy Nuclear South Entergy Operations, Inc.

17265 River Road Killona, LA 70057-3093 OIL Tel. 504 739 6715 Fax 504 739 6698 rmurill@entergy.com Robert J. Murillo Licensing Manager Waterford 3 W3F1-2008-0008 June 30, 2008 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Annual Report on Westinghouse Electric Company LLC Combustion Engineering Emergency Core Cooling System Performance Evaluation Models Waterford Steam Electric Station, Unit 3 (Waterford 3)

Docket No. 50-382 License No. NPF-38 Dear Sir or Madam This letter transmits the 10 CFR 50.46 annual report pertaining to Emergency Core Cooling System (ECCS) Evaluation changes for Calendar Year 2007 for Waterford 3. The Westinghouse 1999 Evaluation Model (EM) is used in the Waterford 3 Large Break Loss-of-Coolant Accident (LBLOCA) ECCS performance analysis. There were no error corrections to the 1999 EM in calendar year 2007'except for an editorial correction in the error message for CEFLASH-4A. Also, there were no changes or error corrections in calendar year 2007 to the Westinghouse Supplement 2 Evaluation Model (S2M), which is the EM used in the Waterford 3 Small Break Loss-of-Coolant Accident (SBLOCA) ECCS performance analysis. There were no model changes in Calendar Year- 2007 that had a significant impact on peak clad temperature (PCT). Attachment 1 provides a summary of the calendar year 2007 changes that were made to the 1999 EM. The changes had no or insignificant impact on peak clad temperature for Appendix K large and small break LOCAs.

There are no new commitments contained in this submittal. Please contact Robert J.

Murillo at (504) 739-6715 if you have questions regarding this information.

RJM/GCS/ssf Attachment(s): Summary of the Calendar Year 2007 changes to the Westinghouse 1999 EM for Waterford 3

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W3F17-2008-0008 Page 2 cc: Mr. Elmo E. Collins, Jr.

Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop O-07D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004

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Attachment I W3FI-2008-0008 Summary of the Calendar Year 2007 Changes to the Westinghouse 1999 EM for Waterford 3 to W3F1 -2008-0008 Page 1 of 2 2007 Westinghouse Evaluation Model Changes for Waterford 3

" Proprietary Notations in Source and Output Modifications to the source file notation and output edit headers for the major computer codes of the 1999 EM have been made to indicate the copyright status and proprietary class in conformance with Westinghouse policy.

" Flow Path Enthalpy Transport Numerical Stability in CEFLASH-4A An upgrade to the flow path enthalpy transport model has been implemented as an optional process improvement to give the user additional numerical stability control other than modifying time step size.

" Correction of an Incorrect Error Message in CEFLASH-4A The editing logic in CEFLASH-4A, the blowdown thermal-hydraulics systems code of the 1999 EM, has been modified to prevent an incorrect error message from causing the utility script, which manages the operation of the 1999 EM, from an improper termination.

" Upgrade to the Auto-Axial Power Shape Option in STRIKIN-II An upgrade to the computer logic has been implemented to improve the process for matching the prescribed target ASI for the 1999 EM. The improvement more accurately achieves the target ASI over a broader range of conditions than before.

" Auto-Generation of the STRIKIN-II Base and Case Decks A process improvement has been implemented to automatically generate the STRIKIN-II base and case decks in a manner consistent with the fuel performance data set from the FATES3B computer code, which provides initial conditions for fuel rod stored energy and rod internal pressure.

" Increase the Number of Radial Regions for COMZIRC The core-wide cladding oxidation is calculated using the COMZIRC computer code.

COMZIRC represents the core fuel pin census with a table of values of fuel rod power versus fraction of rods. The current version allows a maximum of only 12 radial intervals to represent the core. The purpose of this change is to increase the radial detail from 12 to 120 intervals, thus allowing enhanced control of the discretionary conservatism needed to bound the core pin census with the COMZIRC input table.

to W3F1-2008-0008 Page 2 of 2

" Assignment of CEFLASH-4A Regions in COMZIRC The assignment- of the CEFLASH-4A radial regions to the radial pin census in COMZIRC was previously a manual operation performed by the user. Computer logic has been implemented in COMZIRC to automatically confirm and/or provide the assignment of the CEFLASH-4A radial regions to the pin census.

" Implementation of Cathcart-Pawel Oxidation Model and Pre-Transient Oxidation Model The alternate oxidation model and pre-transient oxidation model are used to study various aspects of new embrittlement criteria being suggested by NRC and to provide an alternate means to address NRC questions regarding the calculation of the peak cladding oxidation percentage in applications of the 1999 EM to CE plants.

The new UCI (User Control Interface) options provide for automatic activation of input vector changes and ensure consistency among the other computer codes of the 1999 EM.

X Update to the Auto-Generation of the STRIKIN-II Base and Case Decks These updates are categorized as general code maintenance changes to improve the operation and flexibility of this feature of the code.