ML20126F522

Forwards Rev 1 to OPPD-NA-8301-P, Nuclear Analysis Reload Core Analysis Methodology Overview. Application for Withholding Info from Public Disclosure Encl.Encl Withheld (Ref 10CFR2.790)

ML20126F522
Person / Time
Site:	Fort Calhoun
Issue date:	06/13/1985
From:	Andrews R OMAHA PUBLIC POWER DISTRICT
To:	Butcher E Office of Nuclear Reactor Regulation
Shared Package
ML19344C044	List: ML20126F522
References
LIC-85-237, NUDOCS 8506170514
Download: ML20126F522 (5)

Text

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o Omaha Public Power District 1623 Harney Omaha, Nebraska 68102 402/536 4000 June 13,1985 L IC-85-237 1

Mr. E. J. Butcher, Acting Chief Office of Nuclear Reactor Regulation Division of Licensing U. S. Nuclear Regulatory Commission Washington, DC 20555

References:

(1) Docket No. 50-285 (2) "0maha Public Power District Nuclear Analysis Reload Core Analysis Methodology Overview," OPPD-NA-8301-P, September 1983.

(3) " Statistical Combination of Uncertainties," CENPD-257(0)-P, November, 1983.

(4) " Acceptance for Referencing of Licensing Topical Report CENPD-207, CE Critical Heat Flux: Critical Heat Flux Cor-relation for CE Fuel Assemblies with Standard Spacer Grids; Part 2 Non-Uni fonn Axial Power Distribution," letter C. E.

Thomas (NRC) to A. E. Scherer (CE), dated November 2,1984.

(5) Letter OPPD (R. L. Andrews) to NRC (James R. Miller), dated March 6,1985, " Fort Calhoun Cycle 10 Reload."

Dear Mr. Butcher:

Core Reload Methodology Changes for Cycle 10 The Omaha Public Power District is currently perfonning the Cycle 10 core re-load safety analysis for the Fort Calhoun Station. The Cycle 10 core is de-signed to further reduce the flux to the reactor vessel beltline welds to min-imize the RTNDT shift. The additional flux reduction will be accomplished by use of part length poison rods inserted in peripheral assemblies located near the critical weld locations. Use of the poison rods (and the associated flux shifts) result in increases in both the total integrated radial peaking factor (FRT) and the total unrodded radial peaking factor (FxyT ). To accommdate the increased radial peaking, improvements in the monitoring systems are required.

These improvements consist of converting the Thennal Margin / Low Pressure (TM/

LP) calculators to the " standard system" type units which include axial shape dependency and the addition of a Mini-CECOR/Better Axial Shape Selection Systen ar[5 d.

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Mr. E. J. Butcher June 13,1985 Page Two (BASSS) for incore monitoring of the DNB and Linear Heat Rate Limiting Condi-tions for Operation. The above modifications and fuel system design changes require revisions to the District's approved reload methodology contained in the overview topical report, Reference (2), which were previously identified in Reference (5).

The attached revision of Reference (2) discusses Mini-CECOR/BASSS which will be installed on the District's ERF computer system. As previously discussed with members of your staff, the District is in the process of moving " plant compu-ter" functions from the PRODAC-250 computer to the ERF computer. All inputs necessary for the execution of Mini-CECOR/BASSS have been or will be trans-ferred to the ERF computer prior to Cycle 10 startup with one exception. Pro-blems have arisen with transferring the primary CEA position indication systen currently installed on the PRODAC-250. The District is assessing utilizing the secondary CEA position indication systen (This is the reed switch systen which is the primary CEA position indication system for most CE-built NSSS) for this function. This systen is also utilized by the rod block function. If it is not possible to install the lead bank secondary CEA position indication system on the ERF computer, District personnel will manually enter the lead bank CEA position into the ERF computer any time the position of the lead bank is changed and Mini-CECOR/BASSS is being utilized to monitor the DNB Limiting Condition for Operation (LCO). The District considers manual entry of CEA

- position to be satisfactory for this method of DNB LC0 monitoring because Fort Calhoun Station operates with all CEA's withdrawn from the core approximately 90% of the time Mini-CECOR/BASSS would be utilized for DNB LC0 monitoring (based on an assessment of reactor operation during Cycles 8 and 9) and the fact that the current DNB LC0 parameters of cold leg tenperature, pressurizer pressure and axial shape index are manually monitored once per shift [ Technical Specification 3.10(7)].

In its methodology for thennal-margin analysis the District utilizes the CE-1 Critical Heat Flux Correlation for 14 x 14 CE type fuel. The NRC has recently issued a Safety Evaluation Report, Reference (4), for the CE Topical Report CENPD-207, "CE Critical Heat Flux: Critical Heat Flux Correlation for CE Fuel Assemblies with Standard Spacer Grids; Part 2 Non-Unifonn Axial Power Distribu-tion," which approves a 14 x 14 CE-1 correlation limit of 1.15. The District is modifying its reload methodology to reflect the approval of the 1.15 limit.

Some of the above changes have an impact on the District's Statistical Combina-tion of Uncertainties (SCU) methods and topical report [ Reference (3)]. The

- SCO program will be updated to reflect the changes in the TM/LP calculators and the addition of the Mini-CECOR/BASSS algoritten. In addition, the approved 14 x i 14 CE-1 correlation limit of 1.15 will be used as the new base value in the SCU analysis. All of the analysis in support of the SCO program will be perfonned by Combustion Engineering personnel at their Windsor, Connecticut facility.

Since no changes to the approved SCO methodology will be made, the update of the SCU topical report will be included in the submittal to the Commission of the Cycle 10 Core Reload Safety Analysis.

The Cycle 10 setpoints will be generated based on these methodology changes. I Combustion Engineering will provide revised setpoint manuals and train appro i

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Mr. E. J. Butcher June 13,1985 Page Three priate District personnel on the methodology changes. The training will be completed before District personnel develop the Cycle 10 setpoints.

The reload methodology changes affect the methodology overview topical, Refer-ence (2). Attachment 1 is the revised methodology overview topical, OPPD-NA-8301-P, Revision 1. Changed portions of the text are denoted by vertical lines in the right-hand margin. The document has been reissued to reflect the changes in page numbering due to the addition on Page 1 and the subsequent shift of the text. Other changes have resulted from the addition to the refer-ences and subsequent renumbering. Attachment 2 is a brief explanation of each change. Attachment 3 is a non-proprietary version of the topical.

Please note that pursuant to 10 CFR 2.790(b)(1), certain portions of the attached information has been deemed trade secrets and/or privileged commercial infonnation by Combustion Engineering, Inc. (CE) and Exxon Nuclear Company, Inc. (ENC). Accordingly, please find attached the District's application for withholding this infonnation fran public disclosure.

Sincerely, R. L. Andrews Division Manager Nuclear Production RLA/DJM/rh Attachment cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.

Washington, DC 20036 Mr. E. G. Tourigny, NRC Project Manager Mr. L. A. Yandell, NRC Senior Resident Inspector

,,.n BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION In the Matter of )

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OMAHA PUBLIC POWER DISTRICT ) Docket No. 50-285 (Fort Calhoun Station, )

Unit No.1) )

APPLICATION FOR WITHHOLDING IWORMATION FROM PUBLIC DISCLOSURE Pursuant to Section 2.790(b)(1) of the regulations of the Nuclear Regulatory Commission ("the Commission"), Omaha Public Power District ("the District")

submits this application to withhold certain information from public disclo-sure. Applicant has obtained this information from documents which identify this information as being owned by Combustion Engineering, Inc. (CE) or by Exxon Nuclear Company, Inc. (ENC). It is the opinion of CE and ENC that the information in question contains trade secrets and/or privileged or confiden-tial consercial or financial information. The CE and ENC information was pur-chased by the District under a proprietary information agreement.

The information for which proprietary treatment is sought is contained in the following document:

OPPD-NA-8301-P, Rev. 01, Reload Core Analysis Methodology Overview, J une , 1985.

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The document has been appropriately designated as proprietacy. l

This information was obtained by the District from documents for which CE and ENC have executed affidavits which set forth the bases on which the infonnation may be withheld from public disclosure by the Commission.

Respectfully Submitted, OMAHA PUBLIC POWER DISTRICT By R. L. Andrews Division Manager Nuclear Production Sworn to before me on this

/3 CG day of June,1985.

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