ML19224D300
| ML19224D300 | |
| Person / Time | |
|---|---|
| Site: | Catawba, Perkins, Cherokee  |
| Issue date: | 05/07/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Dail L DUKE POWER CO. |
| References | |
| NUDOCS 7907110318 | |
| Download: ML19224D300 (2) | |
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NUCLEAR HEGULATORY COMMISSION REGION ll
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In Reply Refer To:
RII:JPG 50-413, 50-414 50-488, S M 89 490 M O-491 s 5_0-492, 50 J-3]/
Duke Power Co=pany Attn:
Mr. L. C. Dail, Vice President Design Engineering P. O. Box 33189 Charlotte, North Carolina 28242 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients vill review the information for possible applicability to their facilities.
No specific action or response is requested at ;his time.
If further NRC evaluations so indicate, an 12 Circular or Bulletin will be issued to recc=nend or request specific licensee actions.
If you have ques-tions regarding this matter, please contact the Director of the appro-riate NRC Regional Office.
Sincerely, aces P.
b Director
Enclosure:
1.
IE Information Notice No. 79-11 2.
Draft Transmittal Letter t
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339
MAY 7 1979
. Duke Power Company cc w/ encl:
D. G. Beam, Project Manager Post Office Box 223 Clover, South Carolina 29710 J. T. Moore, Project Manager Post Office Box 422 29340 Gaffney, South Carolina O
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCE N T WASHINGTON, D.C.
20555 May 7, 1979 IE Information Notice No. 79-11 LOWER REACTOR VESSEL HEAD INSULATION SUPPORT PROBLEM 1
Virginia Electric and Power Cocpany, North Anna Power Station No.
reported on November 8, 1978, a field codification pertaining to the lower vessel head in=ulation support system which was not seistically A subsequent stress analysis analyzed at the time of codification.the ASME Code allowable stress and the yield s indicated that the operating base earthquake (OBE) on some of the instrument guide tubes were exceeded.
1 field modification, the lower vessel head For the North Anna No.
insulation was supported ly angle brackets that are cla= ped onto the This additional gridwork to about 20 of the 53 instrv=ent guide tubes.
load on the guide tubes was not considered in the original stress analysis.
The maximu= stress occurs in the socket velds between the Thichle guide The tubes and the Instru=entation nozzles that penetrate the vessel.
maximum stress was about 70 percent of the ulticate and, therefore, viclation of the pressure boundary would not be expected.
VEPCO plans to modify the supporting arrange =ent by building a fracework 9
underneath the insulation, which will take the loading off the guide tubes.
All holders of operating licet..es and/or construction perndts should be aware of the potential problem of exceeding the allowable stress and the yield stress for OBE.
This Inforeation Notice is provided as an early notification of a It is expected that recipients will review possibly af nificant catter.
E No the inforestien for possible applicability to their facilities.
If further NRC specific action or response ir requested at this time.
evaluations so iniicate, an IE Circular or Bulletin will be issued to specitic J icensee actions.
If you have questions reco==end or request regarding the matter, please con, tact the Director of the appropriate NRC Ltgional Office.
No written response to this information notice is required. -
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7906060158
Enclosure IE Information Notice No. 79-11 Page 1 of 1 May 7, 1979 LISTING OF IE INFORMATION NOTICES ISSUED IN 1979 Date Issued To Information 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 At. tempted Extortion -
2/2/79 All Fuel Facilities Low Enriched Uranium 79-03 Limitorque Valve Geared 2/9/79 All power rea: tor Limit Switch Lubricant facilities with an 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 Ieproper M *erialo 3/21/79 All power reactor facilities with an in Saf ety-Related Component OL or CP 79-06 Stress Analysic of
'3/23/79 All HMders of Reactot 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 Contamincted Syste=s with facilities with an Service Air Syste=s Used OL and Pu Processing As the Source of Breathing fuel facilities Air 79-09 Spill of Radioactively 3/30/79 All power reactor Contacinated Resin facilities with an OL 79-10 Nonconforcing Pipe 4/16/79 All power reactor facilities with a Support Struts a '
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