ML19339A654
| ML19339A654 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 10/27/1980 |
| From: | Clayton F ALABAMA POWER CO. |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8011040469 | |
| Download: ML19339A654 (5) | |
Text
Alabama Power Company 600 North 18th street I
Post Office Box 2641 Birmingham. Alabama 3$291 l
Te6ephone 205 250-1000 m
F. L CLAYToN, JR.
Alabama Power senior Vice President the southem eec!rc system October 27, 1980 Docket No. 50-364 Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Attention: Mr. A. Schwencer Gentlemen:
JOSEPH M. FARLEY NUCLEAR PLANT - UNIT 2 SEISMIC OUALIFICATION REVIEW Enclosed are Alabama Power Company's responses to questions that were asked by your consultants at Brookhaven National Laboratory regarding the subject issue.
Should you have any questions, please call.
Yours truly, F. L. Clayton, Jr.
CLB:de Enclosure cc: Mr. R. A. Thomas (w/ enclosure)
Mr. G. F. Trowbridge Mr. W. H. Bradford Mr. L. L. Kintner f ool 5
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a QUESTION 1:
Regarding the river water and service water pumps, what is the nature of the connection between the pump and pipe attachment flanges?
RESPONSE
The discharge piping flange is joined to the pump discharge flange through a bellows-type expansion joint, which is designed to minimize the piping loads transmitted to the pump flange. This expansion joint design includes tie rods to limit the axial expansion of the joint and balance the hydraulic forces created by the system internal pressure during operation.
While this arrangement allows the transmission of tensile loads from the piping system to the pump discharge flange, it does effectively block the transmission of moments and compressive loads. Therefore, loads and stresses on the pump flange are maintained substantially lower than the loads and stresses on the analocous piping system flange on the other side. of the expansion joint. Since the pump discharge flange is of e design and pressure rating equivalent to that of the piping flange, it is acceptable based on comparison with the piping flange, which is qualified as par' of the overall piping system analysis.
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. urn QUESTI0tl2:
Address the following two concerns regarding the contair.T.ent air cooli.ng units:
(a) For the cooling coil seismic analysis in Appendix C, a reduction factor of 1.35 was used to calculate the maximum stress of the cooling coil as shown in Table 1.
Can this factor be substantiated? Would the stress that is developed without the use of the factor still be less than the allowable?
(b) For the fan / motor assembly documentation, refer to Appendix D, sheet 2.
Our calculations show that the stress in the hold-down bolt is 30,071 psi.
Is this stress within the allowable of the bolt material used for the component?
RESP 0tlSE:
(a) The coils used for the Farley air cooling units are of the same design as the 1300 lb. coils addressed in the stress report section of the seismic analysis. However, the Farley coils have fewer rows of tubes, and hence weigh only 960 lbs. The inertial forces, and hence seismic stresses, for the Farley coils were obtained by multiplying the corresponding stresses for the 1300 lb. coils by a reduction factor of 1.35, which was derived by ratioing the relative weights of the respective coils. This linear relationship, based on coil weight, is valid provided the fundamental frequency of the coil is sufficiently high to consider the coil rigid. The fundamental frequency for the front mounted 1300 lb. coil is 390 hr, which is well within the rigid range.
If the 1.35 reduction factor was. removed from the Farley analysis, the resulting coil stresses would still be acceptable for the Farley units.
(b) Upon reexamining the calculations of the maximum bolt stresses, it was determined that an error had been made and the maximum bolt stresses should indeed be 30,071. Since initial installation, several of these units have been removed for maintenance and/or repair. During reinstallation, holddown bolts other than those originally supplied with the equipment were used because the original bolts were damaged or lost during the maintenance operation.
E Although we have not compiled the documentation to support the original bolts provided by the supplier, we have established with the supplier that the original bolts provided had a minimum allowable stress greater than 33,000 psi. Also, the supplier has since revised the procedure used to calculate stresses in this joint to remove some of the excessive conservatisms. The newer procedure, while still conservative, yields calculated stresses for these bolts of approximately 12,700 psi.
We are in the process of modifying the holddown bolts to add locking devices.
In light of the response time required to support the t'RC's efforts to issue a favorable Farley SER, it is more expedisious to replace the subject bolts during the mocification than to perform the e -
3.s Question 2 (Continued)
Response
material documentation compilation that would be required to sub-stantiate the bolts presently installed. Consequently, this holddown bolt design modification now provides for reolacing the bolts with new bolts having a minimum allowable working stress in excess of 30,071 psi.
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QUESTI0ft3:
Address the following two concerns regarding the seismic analysis for the 48-inch nuclear purge valves:
(a) On page 19, the formula for the direct shear stress has a factor of 2/3. Is this number correct?
(b) On page 21, should there be a factor of 1/2 in front of the equation given for hub bolt stress?.
i RESP 0ftSE:
(a) The formula for direct shear stress should not have the 2/3 factor.
Stresses were recalculated and found to be less than the allowable.
(b) The equation given in the report is a convenient and conservative approximation of the correct equation, which is h+f[o
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