ML19224D297
| ML19224D297 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 05/07/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Zechella A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 7907110310 | |
| Download: ML19224D297 (1) | |
Text
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m UNIT ED STATES ga m:009
- 1 jo, NUCLEAR REGULATORY COMMISSION i
$ ^ 3 c ( ',g REGloN il 101 M ARIETT A ST RE ET.N.W.
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RIl1JF0 D?j Offs. ore Power Systems 5
Attn:
Mr. A. P. Zechella, President 8000 Arlington Expressway P. O. Box 8000 Jacksonville, Florida 32211 Centlemen:
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 this time.
If further NRC evaluations so indicate, an IE Circular cr Bulletin vill be issued to reco==end 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,
.-A aces P.
b Director
Enclosure:
1.
IE Inforcation Notice No. 79-11 2.
Draft Trans=ittal Letter s"*"r 7907110 g/O
UNITED STATES NUCLEAR REGULATORY COMMISSICN OFFICE OF INSPECTION AND ENFORCDDT Wast 11NGTON, D.C.
20555 May 7, 1979 IE Information Notice No. 79-11 IN ER REACTOR VESSEL HEAD INSULATION SUPPORT PROBLEM I
Virginia Electric and Power Company, North Anna Power Station No.
reported on November 8, 1978, a field modification pertaining to the lower vessel head insulation support system which was not seis=ically A subsequent stress analysis analyzed at the rice of modificaticn.
indicated that the ASME Code allowable stress and the yield stress for the operating base earthquake (OBE) on some of the instrument guide tubes were exceeded.
For the North Anna No. 1 field modification, the lower sessel head
~
insulation was supported by angle brackets that are cla= ped onto the 20 of the 53 instrument guide tubes. This additional grideork to about load on the guide tubes was not considered in the original stress analysis.
stress occurs in the socket velds between the Thieble guide The maxima:
tubes and the Instrumentation nozzles that penetrate the vessel.
The maxieu= stress was about 70 percent of the ulti= ate and, therefore, violation of the pressure boundary would not be expected.
VEPC0 plans to modify the supporting arrangement by building a fratevork underneath the insulation, which will take the loading of f the guide tubes.
All holders of cperating licenses and/or construction permits should be aware of the potential problem of exceeding the allowable stress and the yield atress for OBE.
This 13 formation Notice is provided as an early notification of a It is expected that recipients vill review possibly significant catter.
No the inforcation for possible applicability to their facilities.
this tiee.
If further NEC specific action or response is requested at evaluations so indicate, an IE Circular or Bulletin will be issued to reco==end or request specific licensee actions.
If you have questions the Director of the appropriate NRC regarding the catter, please contact Regional Office.
No written response to this inforcation notice is required. '
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33J 7006060158
Enclosure IE Information Notice No. 79-11 Page 1 of 1 May 7. 1979 LISTING OF IE INFOPJMTION NOTICES ISStrED 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 Attecpted Extortion -
2/2/79 All Fuel Facilities Low Enriched Uranium 79-03 Limitorque Valve Geared 2/9/79 All power reactor 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 Icproper Materials 3/21/79 All power reactor f acilities with an in Safety-Related Cocponents OL or CP Stress Analysis of
'3/23/79 All Colders of 79-06 Reactor OL or CP Safety-Related Piping 79-07 F vture of Radwaste Tanks 3/26/79 All power reactor f acilities with an OL or CP 79-08 Interconnection of 3/28/79
/.11 power reactor (c-111 ties with an Contaminated Systems with OL and Pu Processing Service Air Systees Used fuel facilities As the Source of Breathing Air 79-09 Spill of Radioactively 3/30/79 All power reactor f acilities with an Contoeinated Resin OL 79-10 Nonconfor ing Pipe 4/16/79 All powar reactor facilities with a Support Struts a '
CP 7
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