ML20204H843
| ML20204H843 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 08/04/1986 |
| From: | Bailey J GEORGIA POWER CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| GN-1008, NUDOCS 8608080219 | |
| Download: ML20204H843 (2) | |
Text
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b Georgia Power Company Post Offic] Box 282 Waynesbora Georgia 30830 Telephone 404 554 9961 404 724-8114 Southern Company Services, Inc.
fbst Office Box 2625 Birmingham, Alabama 35202
- a"oa* 2 5 856 "
Vogtle Project August 4, 1986 Director of Nuclear Reactor Regulation File: X7BC35 Attention:
Mr. B. J. Youngblood Log:
GN-1008 PWR Project Directorate #4 Division of PWR Licensing A U. S. Nuclear Regulatory Commission g
Washington, D.C.
20555 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 AND CPPR-109 V0GTLE ELECTRIC GENERATING PIANT - UNITS 1 AND 2 CODE ADDENDA 0F RECORD FOR PIPE SUPPORT ALLOWABLE STRESS VALUES
Dear Mr. Denton:
During a review of past technical directives issued to the structural engineers working on the Vogtle Electric Generating Plant (VEGP), it was discovered that the through thickness stress allowable of the AISC Code has been utilized in lieu of the required allowable of the 1974 Edition with Addenda through Summer 1975, ASME Section III Code for Subsection NF applications for which VEGP is committed. Although the AISC allowables are consistent with the Table NF-3292.1-1, this discrepancy of Code values was identified as being in violation of the ASME Section III Bechtel Quality Assurance Manual. Corrective actions have been taken to ensure compliance with the Code of Record as defined in the FSAR.
Our review of these Code paragraphs indicate that the ASME Code had placed the stress limit of 0.3Sy in addition to the allowables of Table NF-3292.1-1 to guard against lamellar tearing of the base materials. This conservative limitation was imposed for the tensile load at the welded connections, so that l
the stress in the through thickness direction was limited to 30% of the base l
metal yield strength. This restriction resulted in large weld sizes that did not relieve the problem of tearing of the base material. This additional weld metal can produce significant strains in the parent material resulting in the joining up of base metal inclusions, therefore, the potential for lamellar tearing still existed. Through the use of the 1980 Edition of the ASME Section III Code provision, smaller fillet welds may be used with significantly reduced possibilities of lamellar tearing.
j 8600080219 860804 4
PDR ADOCK 0500 a
i
Director of Nuclear Reactor Regulation File: X7BC35 August 4, 1986 Log:
GN-1008 Page 2 In comparing the allowable stress limits of Table NF-3292.1-1 for the 1974 through 1980 Edition of ASME Section III Codes, there were no significant changes with the exception that the overly restrictive 0.3Sy limit. This 0.3Sy limit was removed in the 1980 Edition, thereby allowing the stress limits to meet Table NF-3292.1-1.
Georgia Power Company respectfully requests authorization to exclude the stress limitation of 0.3Sy for subparagraphs NF-3226.5, NF-3321.1(c),
l NF-3392.1 and Mandatory Appendix XVII, Figure XVII-2211(c) of the 1974 Edition with Addenda Summer 1975. Exclusion of this 0.3Sy restrictive limit will provide consistent stress limits between the AISC and NF jurisdictional boundary.
If your staff requires any additional information, please do not hesitate to contact me.
Since rely,
[. J i
J. A. Bailey l
Project Licensing Manager JAB /sm Attachment xc:
R. E. Conway NRC Regional Administrator i
R. A. Thomas NRC Resident Inspector l
J. E. Joiner, Esquire D. C. Teper B. W. Churchill, Esquire W. C. Ramsey M. A. Miller (2)
L. T. Gucwa B. Jones, Esquire Vogtle Project File i
G. Bockhold, Jr.
j.
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