ML20059C198
| ML20059C198 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 10/27/1993 |
| From: | Gates W OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20059C200 | List: |
| References | |
| LIC-93-0270, LIC-93-270, TAC-M82834, TAC-M83465, NUDOCS 9311010048 | |
| Download: ML20059C198 (2) | |
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Omaha Public Power District P.O. Box 399 Hwy. 75 - North of Ft.Calhoun Fort Calhoun, NE 680234399 402/636-2000 October 27, 1993 LIC-93-0270 l
U. S. Nuclear Regulatory Commission ATTN: Document Control Desk i
Mail Station PI-137 Washington, DC 20555
References:
1.
Docket No. 50-285 2.
Letter from OPPD (W. G. Gates) to NRC (Document Control Desk) dated October 15, 1993 (LIC-93-0258) 3.
CEN-604, Revision 01, " Evaluation of Low Upper Shelf Energy for Combustion Engineerin Nuclear Steam Supply Systems Reactor Pressure Vessels," gdated September 1993 Gentlemen:
SUBJECT:
Updated Information on Reactor Vessel Structural Integrity and Construction Period Recovery for Fort Calhoun Station (TAC Nos.
82834 & 83465)
Recently, staff members from the NRC and Omaha Public Power District (0 PPD) discussed information provided in the previous OPPD submittals concerning reactor vessel structural integrity and the construction period recovery for Fort Calhoun Station (FCS). As a result of these discussions and to facilitate staff review of the subject issues, OPPD is providing a copy of the Reference 3 topical report (Enclosure 1).
The plant-specific analysis by ABB Combustion Engineering is contained in.
This analysis used the equations contained in NUREG/CR-5729 to evaluate axial flaws in the 2-410 and 3-410 longitudinal vessel welds.
The l
plant-specific analysis concludes that the longitudinal vessel welds are less limiting than the base plates as analyzed in Reference 3.
Therefore, the Reference 3 report has been determined to provide a generic bounding analysis for FCS. The FCS reactor vessel is described in the generic report as 140 inches in diameter.
Although the equivalent margins analysis described above provides assurance of vessel integrity, OPPD will also continue efforts towards satisfactory estimation of initial Upper Shelf Energy (USE) values for welds 2-410 and 3-410. USE values for these welds must be derived from generic data since specific data is not available.
OPPD is working with ABB Combustion Engineering to evaluate the effects of different weld flux types on physical properties of the welds; this effort will provide additional confidence in the estimated initial USE values and demonstrate end-of-life compliance with the applicable 10 CFR 50 Appendix G criterion.
290041 Yi 9311010048 931027 PDR ADOCK 05000285
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U. S. Nuclear Regulatory Commission LIC-93-0270 Page 2 In conclusion, the ABB Combustion Engineering USE report (Enclosure 1) and the FCS weld USE equivalent margins analysis (Enclosure 2) demonstrate that all FCS vessel weld materiah will, at the proposed August 2013 end-of-life, have USE values greater than the requited 36 ft-lbs documented in Enclosure 2.
Based on the above and previously submitted in formation, OPPD requests expeditious approval by the NRC of the Construction Period Recovery requested for FCS.
Please contact me if you have any questions.
Sincerely, M.
.M W. G. Gates Vice President WGG/tcm Enclosures c:
LeBoeuf, Lamb, Leiby & MacRae (w/o enclosures)
J. L. Milhoan, NRC Regional Administrator, Region IV (w/o enclosures)
R. P. Mullikin, NRC Senior Resident Inspector (w/o enclosures)
S. D. Bloom, NRC Project Manager
LIC-93-0270 Combustion Engineer _ing Owners Group Report CEN-604, Revision 01 Evaluation of Low Upper Shelf Energy for Combustion Encineering Nuclear Steam Suppfy Systems Reactor Pressure Vessels September 1993 l
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