ML20100H434

Forwards WCAP-10786, Analysis of Capsule U from Duke Power Co McGuire Unit 1 Reactor Vessel Radiation Surveillance Program, Per App H to 10CFR50.Based on Rept,Rev to Tech Specs May Be Necessary.Nrc Will Be Advised If Rev Needed

ML20100H434
Person / Time
Site:	McGuire
Issue date:	04/05/1985
From:	Tucker H DUKE POWER CO.
To:	Adensam E, Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20100H438	List: ML20100H434 ML20100H458
References
TAC-59962, TAC-59963, TAC-61512, TAC-61513, NUDOCS 8504090178
Download: ML20100H434 (2)

Text

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• DUKE POWEli GOEPANY e.o.nox aa:Bo OHAMLOTTE. N.C. 28242 HAL H. TUCKER TELEPHONE vum reanspawr (704) OT+4531 April 5, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Ms. E. G. Adensam, Chief Licensing Branch No. 4

Subject:

McGuire Nuclear Station, Unit 1 Docket No. 50-369

Dear Mr. Denton:

l Pursuant to 10 CFR50, Appendix H, please find attached a report entitled

" Analysis of Capsule U from the Duke Power Company McGuire Unit 1 Reactor Vessel Radiation Surveillance Program", WCAP-10786.

Based on an initial and preliminary review of the results of this capsule evaluation, it appears that the present heatup and cooldown curves in Technical Specification will need to be revised.

Plant heatup and cooldown operating limits generated as part of this report differ I from the original 10 year plant operating limits identified in the plant technical specifications. The new limits are based on a 10 EFPY neutron fluence of 3.89 x 1018 n/cmZ and RT of178'Fwhgreasthetechnicalspecificationlimitsarebased on a fluence of 2 h x 10 18 n/cm and an RTNDT of 124 F. This difference occurs because Regulatory Guide 1.99 Revision 1 was used to predict radiation damage for the new limit curves whereas Westinghouse prediction methods were used for developing the original limit. curves. In addition, neutron fluence values for

, the limiting weld location have been updated using the latest state of the art i dosimetry methods (energy groups, cross sections, etc.). It should also be noted that in the original analysis the capsules located at 56 and 58.5* vere assumed to provide shielding for the critical longitudinal weld seam located a't 60*.

However, in the new analysis the capsules were not considered as providing shielding because they only shield approximately 30 inches'of 106 inch long weld seam located at 60'.

, Although new plant operating limits have now been developed for the plant, the y old operating limit curves have been determined to be appropriate for up to 4.86 EFPY. McGuire Unit 1 has operated for approximately 2 EFPY to date.

Duke is continuing to review the results contained in this report. If determined to be necessary, a proposed Technical Specification revision will be submitted in a timely manner so as to allow NRC sufficient time to review and approve prior to the present Technical Specification curves becoming non-conservative. '

8504090178 PDR 850405 ADOCK 0500036 , 0 OI Y

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Mr. Harold R. Denton, Director l April 5, 1985 )

Page l l

1 If there are any questions regarding this, please advise.

Very truly yours, pl. cLL.g Hal B. Tucker RLG/mjf Attachment cc: Dr. J. Nelson Grace, Regional Administrator U. S. Nuclear Regulatory Commission

. Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 W. T. Orders Senior Resident Inspector McGuire Nuclear Station Mr. Darl Hood, Project-Manager Division of Licensing Office of Nuclear Regulatory Commission Washington, D. C. 20555 o

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