ML19224D304
| ML19224D304 | |
| Person / Time | |
|---|---|
| Site: | Hatch, Vogtle  |
| Issue date: | 05/07/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | John Miller GEORGIA POWER CO. |
| References | |
| NUDOCS 7907110329 | |
| Download: ML19224D304 (2) | |
Text
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v UNITED STATES g>* RIGuq'o NUCLEAR REGULATORY COMMISSION REGION il y 7, r*
g 101 M ARIETT A ST R E ET, N.W.
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ATLANT A, GEORGIA 30303 o
"AY 71979
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In Reply Refer To:
RIL:JPO.
6 0-321, 50-3663 50-424, 50-4Y5 Georgia Power Conpany Attn:
Mr. J. H. Miller, Jr.
Executive Vice President 270 Peachtree Street, N. W.
Atlanta, Georgia 30303 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the inforcation for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, en IE Circular or Bulletin will be issued to reco==end or request specific licensee actions.
If you have ques-tions regarding this catter, please contact the Director of the appro-riate NRC Regional Office.
S incer'ely,
.~
acies P.
b Director
Enclosure:
1.
IE Inforration Notice No. 79-11 2.
Draft Trans=ittal Letter i
33j 2907110 7 2 ?
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MAY 7 197)
. Georgia Power Company cc v/ encl:
M. Manry, Plant Manager Post Office Box 442 Baxley, Georgia 31513 C. E. Belflower Site QA Supervisor Post Office Box 442 Baxley, Georgia 31513 L. L. Gray, Jr.
Construction Project Manager Post Office Box 329 Baxley, Georgia 31513 K. M. Gillespie Construction Project Mana ger Post Office Box 282 Waynesboro, Georgia 30830 E. D. Grover QA Site Supervisor Post Office Box 282 Waynesboro, Georgia 30830
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 May 7, 1979 IE Inforcetion Notice No. 79-11 1DWER REACTOR VE5SEL HEAD INSUIATION SUPPORT PROBLEM Virginia Electric and Power Co=pany, North Anna Power Station No. I reported on November 8, 1978, a field modification pertaining to the lower vessel head insulation support system which was not seismically analyred at the tice of modification.
A srbsequent stress analysis indicated that the ASME Code allowable stress and the yield stress for the operating base earthquake (OBE) on some of the instrument Euide tubes were exceeded.
For the North Anna No. 1 field modification, the lower vessel head insulation was supported by angle brackets that are clamped onto the gridwork to about 20 of the 53 instrument guide tubes. This additional load on the guide tubes was not considered in the original stress analysis.
The maximum stress occurs in the socket velds between the Thimble guide tubes and the Instrumentation nozzles that penetrate the vessel.
The maximum stress was about 70 percent of the ultimate and, therefore, violation of the pressure boundary would not be expected.
VEPCO plans to modify the supporting arrangement by building a fracework underneath the insulation, which will take the loading off the guide tubes.
All holders of operating licenses and/or construction permits should be aware of the potential problem of exceeding the allowable stress and the yield stress for OBE.
This Information Notice is provided as an early notification of a It ic expected that recipients vill review possibly significant catter.
No the information for possible applicability to their facilities.
th.'s tice.
If further h7C specific action or response is requested at evaluations so indicate, an IE Circular or Bulletin will Se issued to reco==end or request specific licensee actions.
If you. ve questions the Directcr of the appropriate NRC regarding the catter, please contact Regional Office.
No written response to this information notice is required.
J3.;
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7006060158
Enclosure IS Irforr.ation Notice No. 79-11 Page 1 of I May 7, 1979 LI511NG OF IE INFORMATION NOTICES ISSUED IN 1979 Date Issued To Infor=ation Subject Issued Notice No.
79-01 Bergen-Paterson Hydraulic 2/2/79 All power reactor facilities with an Shock and Sway Arrestor OL or a CP 79-02 Attempted Extortion -
2/2/79 All Fuel Facilities Low Enriched Uranium 79-33 Limitorque Valve Geared 2/9/79 All power reactor facilities with an Limit Switch Lubricant OL or a CP 79-04 Degradation of 2/16/79 All power reactor facilities with an Engineered OL or a CP Safety Features 79-05 Use of Improper Materials 3/21/79 All power reactor facilities with an in Safety-Related Components OL or CP 79-06 Stress Analysis of
'3/23/79 All Holders of Reactor OL or CP Safety-Related Piping 79-07 Rupture of Radwaste Tanks 3/26/79 All power reactor facilities with an OL or CP 79-08 Interconnection of 3/28/79 All power reactor Contacinated Syste=s with faci 2ities with an OL and Pu Processing Service Air Syste=s Used fuel facilities As the Source of Breathing Air 79-09 Spill of Radioactively 3/30/79 All power reactor facilities with an Contaminated Resin OL 79-10 Nonconforcing Pipe 4/16/79 All power reactor facilities with a Support Struts a '
CP f
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