ML20205H196
| ML20205H196 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/24/1988 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-62885, NUDOCS 8810280410 | |
| Download: ML20205H196 (2) | |
Text
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I October 24, 1988 I
U. S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
Reference:
Beaver. Valley Power Station, Unit No. 2 Docket No. 50-412, License No. NPF-73 Differential Settlement of Buried Pipes (TAC 62885)
Gentlemen:
The following information is provided in response to your request for additional information dated August 23, 1988.
i Question 2.a:
Provide the d/t (diameter / thickness) ratios for the 30-inch and i
the 24-inch diameter pipes.
1 Responset i
j 60 and 48 respectively.
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i Question 2.b:
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Provide the basis for the allowable limits.
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Response
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i The allowable limit of 3 Sc is obtained from the 1983 ASME III
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code paragraph NC3653.2b for a orie time loading such as building i
j settlement.
It is intended to limit gross plastic deformation I
i and is determined as a suitable limit for buried pipe.
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Question 2.cs i
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Show that no local buckling of the pipe wall occurs at the locations of the critical section of the SWS pipes where the maximum calculated stress of 49548 psi was determined.
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. dock'et No. 50-412, License No. NPF-73 Page 2
Response
Calculatjon 12241-NP(T)-147-X9 Addendum A3 provides a critical buckling check of the 30-inch SWS pipe at nodo 525 where the maximum calculated stress of 49548 psi wa.s determined.
The conclusions stated that the calculated stress of 49548 psi is below 3
Sc allowable (52500 psi) in acco iance with The ASME Boiler and Pressure Vessel
- Code, 1983,Section III, Paragraph NC-3653.2b, for one timu loading such as building settlement.
A further check for critical buckling failure was made for a)
Axial compression - including "P" loading b)
Bending c)
Torsion d)
Shear and found that the loadings being imposed at the critical location node 525 for tension and shear are negligible, therefore no further review was required for these two conditions.
The calculated axial compression stress and bending stress wore evaluated and found to be within allowable limits.
The calculated axial compression stress of 54147 psi is less than 181253 psi and the bonding moment stress of 49548 psi is less than 242451 psi.
- Honco, the piping will not fail by elastic buckling.
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Please inform us of any nood to discuss information related to j
those responses.
1 Very truly yours, L$%
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D. Siebor
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Vico President Nuclear Group Attachment i
cc:
Mr. J. Boall, Sr. Resident Inspector (w/o attachment) i Mr. W. T. Russell, NRC Region I Administrator (w/o attachment)
Mr. P. Tam, Project Manager (w/ attachment) q 4
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