ML20244C926
| ML20244C926 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 04/06/1989 |
| From: | Tam P Office of Nuclear Reactor Regulation |
| To: | Sieber J DUQUESNE LIGHT CO. |
| References | |
| TAC-62885, NUDOCS 8904210054 | |
| Download: ML20244C926 (3) | |
Text
_ _ _ - - _ _ - - _ _
v April.6, 1989 i Docket'No.'50-412 g
+
.Mr. J. D. Sieber, Vice President-Nuclear. Group:
Duquesne~ Light Company
- Post Office Box.4 Shippingport, Pennsylvania:15077:
Dear Mr. Sieber:
L
SUBJECT:
BEAVER VALLEY UNIT 2 - DIFFERENTIAL SETTLEMENT OF BURIED PIPES (TAC 62885)
By letter dated October 24',:1988; you responded to our-latest set of questions -
on the subject issue.; As a result of our continuing review efforts on this
. issue, we developed" additional information needs (See enclosure).. The purpose.
.of this' letter.is to verify that. the ' bending compressive stress in the pipe due: to the reported ' settlement did not exceed the ' allowable compressive stress, and that no local buckling or wrinkling with accompanying wall fracture occurred due to thisisettlement.
Pleasecrespondfwithin 45l days'of' receipt of this letter.
The reporting and/or recordkeeping requirements contained in this letter affect'
' fewer than' ten respondents;. therefore,' OMB clearance is not required under P.L'.96-511.-
Sincerely,
/s/
Peter S. Tam, Senior-Project Manager v{
Project Directorate I-4 89042100$ $90406 5000412 i Division of Reactor Projects I/II A
NU n
Office of Nuclear. Rector Regulation
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Enclosure:
As stated-cc w/en' closure:
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Enclosure BEAVER VALLEY UNIT 2 i
DIFFERENTI AL SETTLEMENT OF BURIED PIPES Request for Additional Information
Reference:
1.
Letter of October 24, 1988 from J. D. Sieber, Duquesne LightCo.(DLC),totheDocumentControlDesk,NRC.
2.
Letter of August 23,.1988 from P. S. Tam, NRC, to-J. D. Sieber DLC.
The licensee has reported that the maximum bending stress' satisfies the require-ment of ASME Section III, 1983, Paragraph NC3653.2b, namely that the allowable limit is 3Sc, that this limit is intended to limit gross plastic deformation, and that it is determined as a suitable limit for buried pipe.
In response to the request to.show that no local buckling of the pipe wall has occurred at'the location where the maximum calculated stress of 49548 psi was determined (node 525)the-licenseestatedthisstressislessthanthecritical compressive stress in bendir.g of 242400 psi. He also stated.that there is an additional axial compression stress of 54150 psi and that this-is less than the g
1 compressive allowable of 181250 psi. These stresses were evaluated on an elastic basisandreportedin' Calculation 12241-NP(T)-147-X9, Addendum 3.
Based on the reported diameter / thickness (D/T) ratios for the 30 inch and the 24 inch lines in Reference 1, these are essentially thin walled cylindrical vessels whose compressive stresses are subject to the limitations of ASME Section III, Para-graphsNC-3112.4andNC-3133.6(b). These compressive stresses are considerably lower than those reported by the licensee. The critical limits calculated on an
- lastic. basis are valid as long as the elastic limit is not exceeded.
In this e
case these have been exceeded by wide margins.
It could also be argued tha NC-3133.6(b) is not applicable to buried piping. We believe that it is i
applicable for local buckling.
1 1
To resolve this issue we request that the licensee provide the following
}
information:
'1.
Calculation 12241-NP(T)-147-X9, Addendum 3.
I
(
2.
The source and basis of the reported axial compression.
j 3.
Independent verification that the high stressed pipe section has not experienced local buckling (wrinkling, crunching and fracture).
4.
The time rate at which settling is occurring.
I a
r p,.A J
.g' S Mr. J. Sieber Beaver Valley Power Station Duquesne Light Company Units 1 & 2
~~
cc:
I Jay E. Silberg, Esquire Bureau of Radiation Protection Shaw, Pittman, Potts and Trowbridge.
Pennsylvania Department of 2300 N Street, N.W.
. Environmental Resources Washington, DC 20037 ATTN:
R. Janati Post Office Box 2063 Kenny Grada, Manager Harrisburg, Pennsylvania 17120, Nuclear Safety Duquesne Light Company Mayor of the Borrough of y
P. O. Box 4 Shippingport-Shippingport, Pennsylvania 15077 Post Office Box 3 Shippingport, Pennsylvania 15077 John A. Lee, Esquire Ashley C. Schannauer -
Duquesne Light Company One Oxford Centre
~
Assistant City Solicitor City of Pittsburgh-301 Grant Street-313 City-County Building '15219 Pittsburgh, Pennsylvania 15279 Pittsburgh, Pennsylvania W.F. Cannichael, Commissioner Regional Administrator, Region I-Department.of Labor U.S. Nuclear Regulatory Commission l
1800 Washington Street East 475 Allendale Road' L
Charleston, West Virginia 25305 King of Prussia, Pennsylvania 19406 i
l-
)
l John D. Borrows Resident Inspector Director, Utilities Department U.S. Nuclear Regulatory Comission Public Utilities Comission Post Office Box 181 1
- 180 East Broad Street Shippingport, Pennsylvania 15077 Columbus, Ohio 43266-0573 Director, Pennsylvania Emergency Management Agency Post Office Box 3321 Harrisburg, Pennsylvania 17105-3321