ML20072Q204

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Documents 901108 Telcon Re Changes to Section 5.3.1 of Safer/Gestr Rept Re Loss of Coolant Analysis
ML20072Q204
Person / Time
Site: Brunswick  Duke Energy icon.png
Issue date: 11/21/1990
From: Loflin L
CAROLINA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NLS-90-239, NUDOCS 9011300315
Download: ML20072Q204 (2)


Text

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Carolina Power & Light Company NOV 211990 SERIAL: NLS 90-239 10CFR50.46 United States Nuclear Regulatory Comeission ATTENTION: Doctueent Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 6 50-324/ LICENSE NOS. DPR 71 & DPR-62 SAFER /CESTR LOCA ANALYSIS REVISION (NRC TAC NOS. 77585 AND 77586)

Gentlemen:

By letter dated September 5, 1990, Carolina Power &' Light Company (CP&L) submitted a request to reference the General Electric Nuclear Report-

-NEDC-31624P " Brunswick Steam Electric Plant Units 1 and 2 SAFER /CESTR LOCA Loss of-Coolant Analysis, Revision 2" for the revised IDCL licensing basis for the Brunswick Plant, Unf ts 1 and 2 using the SAFER /GESTR-IDCA application methodology. On November 8, 1990, a telephone discussion was conducted between CP&L and the NRC Staff during which additional information was provided which describes the changes made to Section 5.3.1-of the SAFER /GESTR report. At the conclusion of the discussion, the Staff. requested that CP&L document the responses provided during the telephone call. This letter documents those discussions.

In Enclosure 2 to Reference 1, the pages updated and the reasons for each change were described. . Section 5.3.1 of both the. original- report (Revision 0) and the revised report (Revision 2) address ~ the applicability of the rated

' Max! mum Average Planar Linear Heat Generation Rate (MAPHLCR) thermal limit to fuel types present in-the core under single' recirculation loop operating conditions. Application of the SAFER /CESTR-LOCA methodology to single loop conditions significantly reduces the, impact of early dry-out (boiling transition) on the overall fuel heat-up during a LOCA. As discussed in

'; Section 5.3.1 of the Revision 0 report, large peak clad temperature (PCT) margins are obtained using SAFER /CESTR-LOCA for single loop conditions, even when rated MAPLHCR values are considered.

3 At the time the Revision 0 report was published, the applicable single loop operation analysis was one performed in 1981 using the SAFE /REFLOOD

methodology. The-SAFE /REFLOOD methodology is based on original

( 10 CFR Part 50, Appendix K requirements. When applied to single loop conditions, these conservativo methods required a MAPLHCR penalty which could

( be applied as. a multiplier on the MAPLHCR thermal limit. The . disc'tssion in J Section 5.3.1 of the Revision 0 report confirmed the applicability.of the results of' the 1981 single loop report with the new LOCA licensing basis.

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  • NLS 90 239 / Page 2 Subsequent to publication of the Revision 0 report, an updated single loop operations analysis was completed in 1990 as reported in Reference 4 of Revision 2. Among other things, this analysis specifically addresses the thermal limit requirements applicable to single loop operations in event of a 1DCA using the SAFER /CESTR LOCA application methodology which had been accepted by the.NRC for referencing as the revised LOCA licensing basis for the Brunswick Plant.

When the Company recognized the Revision 0 report would need to be revised, CP&L decided to include a revision to Section 5.3.1 to delete reference to the 1981 single loop report and instead to reference the 1990 report. As described above and in Section 5.3.1 of Revision 0, sufficient PCT margin exists when evaluated using the SAFER /CESTR-LOCA application methodology, including when rated MAPLHCR values are considered during single loop operating conditions. The revised Section 5.3.1 of Revision 2 states that the rated MAPillGR values for the listed fuel types are supported by the results of the 1990 report. Application of the results of the 1990 single loop report ,

cannot occur without changes to the Technical Specifications for the Brunswick Plant and do not change the results or -conclusions of the Revision 0 report.

Please refer any questions regarding this submittal to Mr. M. R Oates at (919) 546-6063.

Yours very truly, A

b Leonard I. Lo lin Manager Nuclear Licensing Section '

WRM/SC/wrm (\cor\saferral) cc: Mr. S. D. Ebneter Mr. N. B. Le Mr. R. L. Prevatte l

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