ML20216F342

Responds to Rev 1,suppl 1 to GL 92-01 Re Reactor Pressure Structural Integrity Assessment.Rept BWRVIP-08NP Concludes That Small Potential Impact Has Insignificant Effect on Explicit Factor in App G P-T Curves for Plant

ML20216F342
Person / Time
Site:	Cooper
Issue date:	03/09/1998
From:	Swailes J NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-92-01, GL-92-1, NLS980040, NUDOCS 9803180345
Download: ML20216F342 (4)

Text

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NLS980040 March 9,1998 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:

Subject:

BWR Vessel and Internals Project, Update of Bounding Assessment of BWIU2-6 Reactor Vessel Integrity Issues (BWRVIP-46), EPRI Report TR-109727, December 1997 Cooper Nuclear Station, NRC Docket 50-298, DPR-46

References:

1) NRC Generic Letter 92-01, Revision 1, Supplement 1, dated May 19, 1995, " Reactor Vessel Structural Integrity"

2) Letter NLS950174 from G. R. Horn (NPPD) to Document Control Desk (USNRC) dated August 17,1995, "90-Day Response to Generic Letter 92-01, Revision 1, Supplement 1, Reactor Vessel Structural Integrity, Cooper Nuclear Station, NRC Docket 50-298, DPR-46"

3) Letter NLS950223 from G. R. Horn (NPPD) to Document Control Desk (USNRC) dated November 20,1995, "Six Month Response to Generic  !

Letter 92-01, Revision 1, Supplement 1, Reactor Vessel Structural l Integrity, Cooper Nuclear Station, NRC Docket 50-298, DPR-46" )

4) Letter from D. L Wigginton (USNRC) to G. R. Horn (NPPD) dated i July 30,1996, "Closcout for Nebraska Public Power District Response to i Generic Letter 92-01, Revision 1, Supplement I for the Cooper Nuclear Station (TAC No. M92666)"

Per Generic Letter (GL) 92-01, Revision 1, Supplement 1 (Reference 1), the Nuclear Regulatory Commission (NRC) requested Licensees:

Perform a review of their reactor pressure vessel structural integrity assessments in order to identify, collect, and report any new data pertinent to the analysis of the structural integrity of th:ir reactor pressure vessels (RPVs), ,

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NLS980040

.7 March 9,1998 Page 21 ssess the impact of that data on their RPV integrity analyses relative to the requirements of 10 CFR 50.60,10 CFR 50.61, and Appendices G and H to 10 CFR Part 50, and Assess any potential impact oflow temperature overpressure limits or pressure-temperature (P-T) limits.

By letters dated August 17,1995, and November 20,1995, (References 2 and 3, respectively) the' Nebraska Pubic Power District (District) responded to the subject GL and included a discussion on the Boiling Water Reactor Owners' Group (BWROG) activities relative to the supplement. In follow up, by letter dated July 30,1996, (Reference 4) the NRC assessed the District's responses and requested the District provide the NRC with the results of the Owners Groups' programs rela + e to Cooper Nuclear Station (CNS). The following discussion provides this assessment.

The BWROG, as part of t'he Vessel and Internals Project (BWRVIP), developed and submitted BWRVIP-08NP, "BWR Vessel and Internals Project, Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity Issues," in November 19951/2' as an initial response to the issues identified in the GL supplement. Since that time, additional data has been retri eved by owners groups, nuclear steam supply system vendors, and the BWRVIP. As a result, the BWRVIP issued BWRVIP-46 in December 19973' which examines the new data and considers the impact of the results in BWRVIP-08NP for BWR vessels (including CNS) if bounding chemistries are assumed for vessel beltline welds.

As indicated in the BWRVIP-46 report, the new data did not affect the previous conclusion that the equivalent margin analysis for the CNS vessel is bounding for Upper ShelfEnergy (USE) in the beltline welds and that the weld Cu contact has no impact on the USE adequacy in CNS's BWR. ' Furthermore, Table 2-2 of the enclosed BWRVIP-46 report, evaluation of the CNS P-T curves, showed a decrease in the potential impact on P-T curves from 16.5 degrees Fahrenheit to only 3 degrees Fahrenheit by using the new data at a fluence of 18 Effective Full Power Years (EFPY). Conservatisms in the methodology used to calculate this result are detailed in the foot notes on pages B-5 of the BWRVIP-08 report and A-6 of the BWRVIP-46 repon.

l' Letter from J. T. Beckham, Jr. (BWRVIP) to USNRC dated November 15,1995, "BWRVIP Re.sponse to Information Requests in NRC Generic Letter 92-01, Revision 1, Supplement 1, Reactor Vessel Structural Integrity."

2' Letter from Vaughn Wagoner (BWRVIP) to USNRC dated June 27,1996,

" Reclassification of a BWRVIP Report Submitted in Response to Generic Letter 92-01, Revision 1, Supplement 1."

3' Letter from Carl Terry (BWRVIP) to USNRC, dated December 23,1997, "BWR Vessel and Internals Project, Update of Bounding Assessment of BWR/2-6 Reactor Pressure Vessel Integrity Issues (BWRVIP-46)," EPRI Report TR-109727, December 1997.

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• NLS980040 i

. March 9,1998 Page 3 The report concludes that the small potential impact, assuming bounding chemistries, has insignificant effect on the explicit safety factor in the Appendix G P-T curves for CNS.

Accordingly, no changes to the P-T curves are necessary for CNS, Please contact me ifyou require any further information on this matter.

Sincerely,-  !

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J. wat i l Vice Vuclear Energy Presid%t of

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cc: Regional Administrator w/ enclosure USNRC - Region IV Senior Project Manager w/ enclosure USNRC - NP .. Project Directorate IV-1 ,

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,I*l ATTACHMENT 3 LIST OF NRC COMMITMENTS l l A

Correspondence No: NLS980040 The following table identifies those actions committed to by the District in this document. Any other actions discussed in the submittal represent intended or planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Licensing Manager at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.

COMMITTED DATC COMMITMENT OR OUTAGE-None i

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i l PROCEDURE NUMBER 0.42 l REVISION NUMBER 5 l PAGE 9 OF 13 l I