ML19291B093
| ML19291B093 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 07/05/1979 |
| From: | Wuller G ILLINOIS POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| U-0098, U-98, NUDOCS 7908290361 | |
| Download: ML19291B093 (2) | |
Text
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/LLINO/S POWER DOMPANY f..
LO8-79(07-05)-9 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 July 5, 1979 Mr. James G. Keppler Director, Region III Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Clinton Power Station Units 1 & 2 Docket Nos. 50-461 and 50-462 Construction Permits No. CPPR-137 & CPPR-138 This is in reply to your letters of March 8 and June 21, 1979, whereby you forwarded IE Bulletin No. 79-02 and its Revision No. 1,. which reported on a recent problem of structural failures of piping supports for safety equipment.
Responses to action items 1 through 4 of IE Bulletin No. 79-02, Revision No. 1 relative to the Clinton Power Station (CPS) are:
1.
The pipe support base plates for Clinton Unit 1 have been designed based upon rigid plate theory.
Sargent &
Lundy's evaluation of the rigid plate design versus flexible plate design has shown that expansion bolt anchored plate assemblies using rigid plate theory provides factors of safety ranging from 4.0 to 8.7 and that the designs meet NRC criteria.
Enclosed is a description of the analytical model used to verify that pipe supported base plate flexibility is accounted for in the calculation of anchor bolt loads.
2.
Sargent & Lundy has verified that for CPS design appli-cations there is a minimum factor of safety of 4.0 based on bolt design load and ultimate capacity deter-mined from manufacturer's static data for wedge type anchors.
Shell type anchors will not be used at CPS.
3.
The wedge type concrete expansion anchor design allowable stresses were based upon maintaining a minimum factor of safety of 4.0 between the dynamic / cyclic design loads ofanOBEeventandtheboltultimatecapacitydetermined,00 from manufacturer's static load test data.
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James G. Keppler July 5, 1979 4.
To date there have been no piping support base plates for seismic Category I systems installed using concrete expansion anchors.
Auxiliary steel attached to perma-nent embedded plates has been used.
Expansion anchors will be used sparingly, only where it is not practical to use permanent embeds and auxiliary steel.
Such installation will be tested and documented as required.
Sargent & Lundy has advised Illinois Power that test data is apparently not available such that a design basis for dynamic anchor bolt loading can be established.
Therefore, we are evalu-ating a comprehensive dynamic test program for wedge type expan-sion anchors.
The proposed tests would be performed on rigid plate assemolies and include simulated pipe cyclic loads and seismic loads.
We will keep you advised of developments in this area of CPS design and construction.
Sincerely, G. E. Wuller Supervisor - Licensing Generation Engineering Dept.
GEW/cs Enclosure cc:
Director, Division of Reactor Construction Inspection Office of Inspection & Enforcement, USNRC 2012.*
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EVALUATION OF ANALYSIS PROCEDURES FOR THE DESIGN OF EXPANSION ANCHORED PLATES IN CONCRETE k
PREPARED BY:
REVIEWED BY:
M APPROVED BY:
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g May 31, 1979 Sargent &
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Chicag DUPLICATE DOCUMENT Entire document previously entered into system under:
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