ML20206B390
| ML20206B390 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 04/07/1987 |
| From: | Mark Miller Office of Nuclear Reactor Regulation |
| To: | James O'Reilly GEORGIA POWER CO. |
| References | |
| NUDOCS 8704090136 | |
| Download: ML20206B390 (5) | |
Text
4 Docket No.: 50-424 Mr. James P. O'Reilly Senior Vice President - Nuclear Operations Georgia Power Company P.O. Box 4545 Atlanta, Georgia 30302
Dear Mr. O'Reilly:
SUBJECT:
Second Request for Additional Information on Vogtle Spent Fuel Pool Rack Seismic Design The staff has reviewed the Georgia Power Company response dated January 21, 1987, to the staff's request for additional information on the seismic de-sign of the Vogtle spent fuel pool racks dated November 28, 1986.
On the basis of our review, we have determined that additional information is necessary before we can conclude that the seismic design of the racks is acceptable. We request that you provide the information as requested in the enclosure within 60 days of the date of this letter. We are available to meet with your staff prior to your submittal to discuss your anticipated responses.
If there are any questions, contact me at (301) 492-7357.
Sincerely D
Melanie A. Miller, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A
Enclosure:
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Mr. J. P. O'Reilly Georgia Power Company Vogtle Electric Generating Plant cc:
Mr. L. T. Gucwa Resident Inspector Chief Nuclear Engineer Nuclear Regulatory Commission Georgia Power Company P. O. Box 572 P.O. Box 4545 Waynesboro, Georgia 30830' Atlanta, Georgia 30302 Mr. Ruble A. Thomas Depoish Kirkland, III, Counsel Vice President - Licensing Vogtle Project Office of the Consumers' Utility Council Georgia Power Company /
32 Peachtree Street, N.W.
Suite 225 Southern Company Services, Inc.
P.O. Box 2625 Atlanta, Georgia 30303 Birmingham, Alabama 35202 James E. Joiner
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Mr. Donald 0. Foster Troutman, Sanders, Lockerman, Vice President & Project General Manager
& Ashmore Georgia Power Company Candler Building Post Office Box 299A, Route 2
, 127 Peachtree Street, N.E.
Waynesboro, Georgia 30830 Atlanta, Georgia 30303 Danny Feig Mr. J. A. Bailey 1130 Alta Avenue Project Licensing Manager Southern Company Services, Inc.
Atlanta, Georgia 30307 P.O. Box 2625 Carol Stangler Birmingham, Alabama 35202 Georgians Against Nuclear Energy 425 Euclid Terrace Ernest L. Blake, Jr.
Bruce W. Churchill, Esq.
Atlan'ta, Georgia 30307 Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.
Washington, D. C.
20037 Mr. G. Bockhol'd, Jr.
Vogtle Plant Manager Georgia Power Company Route 2, Box 299-A Waynesboro, Georgia 30830 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W., Suite 2900
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Atlanta, Georgia 30323 Mr. R. E. Conway Senior Vice President and Project Director Georgia Power Company Rt. 2, P. O. Box 299A Waynesboro, Georgia 30830 8
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ENCLOSURE Vogtle Spent Fuel Rack Design (FSAR Section 9.1.2.2.1)
Second Request for. Additional Information Because of the lack of background infomation regarding the Vogtle spent' fuel pool rack design, portions of the following questions may not be applicable.
If that is the case, please indicate.
1.
Provide the following regarding the spent fuel structure for review:
Sketches and drawings that show the general layout and design of the a.
spent fuel pool, details of Jiner plates and oads, and installation and arrangements of racks including the leak chase channels.
b.
A description of how the dynamic interaction between the pool struc '
ture and the rack modules was considered, includin'g the key assumptions used in assessing the interaction effects and the value of any dynamic amplification factors. Also include all assumptions made regarding the sumation and phasing consideration *of all rack module dynamic loads.
Analysis results demonstrating the adequacy of the pool floor and liner c.
under rack sliding and impact loads.
d.
Identification of the critical regions of the pool structure from the standpoint of controlling loads or stresses resulting from the pool / rack interaction. List the loads or stresses as appropriate.
Compare the loads and/or stresses to allowable values.
2.
The licensee's response of January 21, 1987, to the staff's November 28, 1986, request for additional information was incomplete.
Please provide '
the following:
A set of fuel rack and fuel assembly drawings to verify the mathe-a.
matical model, b.
Provide a detailed mathematical model of spent fuel rack modules for seismic analysis. Figures 1-1 and 1-2 of your January 21, 1987
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response do not clearly show the coordinate axes, lines of syrretry, types of supports and restraints, application of forces and reactions, boundary conditions and other pertinent infonnation.
In addition to this information, also provide the numerical values and bases of all analytical modeling/ parameters including dimensions weights or masses spring constants damping values of dashpots and dampers gap element properties fluid coupling coefficients coefficient for restitution for impacts multi-rack to rack and multi-rack to pool wall impacts.
. c.
Calculations of the seismic responses and stress analysis of the spent fuel rack modules have not been provided as requested in question 5 of our November 28 letter. Specifically, we need (1) all supporting calculations for model parameters, (2) calculations supporting the assumption that the fuel racks are rigid, (31 de-tailed seismic analysis results, (4) thermal stress evaluations, and (5) various limiting single rack and multi-rack displacements due to seismic loads, d.
Rep rding question 6 of our November 28 request, provide discussion of the i.. thematical model used and numerical values for physical properties of the fictitious springs and damoers in the gaps between the fuel and the cell. Also. provide a comparison of the mathematical model with experimental results or other justification for the use of the model.
e.
The allowable stresses in response to question 8 of the staff's November 28 request should be rechecked to comply With SRP Section 3.8.4, Appendix D (Rev. 1). The statement that the SSE seismic allowables are twice the OBE seismic allowables may not be true.
Provide the basis of this statemen.t and verify' with the load combinations of the FSAR and the acceptance criteria of SRP Section 3.8.4, Appendix D.
f.
In response to question 9 of the staff's November 28 reouest the licensee indicated that acceptance limits in FSAR Table 9.1.2-1 were based on the paper "0T Position for Review and Acceptance of Spent Fuel Storage and Handling Applications." However, acceptance, limits should be based on SRP Section 3.8.4, Appendix D (Revision 1) dated July 15, 1982.
3.
It is not clear how the support legs of the racks are constructed.
Please provide the following information with respect to the design,.
construction, and installation of the support legs:
Sketches showing the upper and lower parts of the support legs, a.
b.
Discussion of rack installation procedures when an adequate clearance to adjust the supports may not be available.
4.
The following requests pertain to rack to rack interactions based on the bounding parameters that (1) use a coefficient of friction of 0.2 and 0.8, (ii) use a center to center spacing of 10.5 inches for rack arrays, and (iii) simulate the rocking behavior of racFs, if multi-racks are used.
Provide a comparison of the impact forces resulting from an analysis a.
of the single rack and multi-rack models.
In the event that the results indicate that the multi-rack model impact force exceeds the single rack impact force, demonstrate that the integrity'of the rack i
is maintained during the design earthquake.
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. b.
In order to better understand the dynamic behavior of the simulated multi-rack model during the design earthquake, provide time-history
' data in tabular or graphical form. The data should include, as a minimum, the translation of each rack as a function of time and the impact forces on the wall as a function of time, c.
Provide a discussion of the fluid coupling analysis including the governing principles, general assumptions, controlling equations and derivations. Address the influence on the impact forces of the modelled racks when the adjacent rows of racks (1) move in phase, (2) move out of phase, and (3) are fixed.
d.
For the simplified single and multi-rack models, compare the impact forces on the fuel assemblies.
In the event that the results indicate that the impact forces on the fuel assemblies using the multi-rack model exceed those of the single rack model, demonstrate the integrity of the fuel assemblies for the design earthquake.
5.
Provide the parameters and constants used in the analysis for impact loading due to the drop of a fuel assembly. Also, provide a summary of ductility ratios utilized to absorb kinetic energy in the tensile, flexural, compressive and shearing modes.
Provide typical calculations indicating the input constants, equations used, and the results of the 4
impact analysis.
6.
Provide considerations regarding the potential impact on the functionality of fuel rack modules due to bowing and localized deformations of fuel assemblies and fuel rack cells.
Provide discussions of all possible effects on racks due to earthquakes such as twisting, bouncing, rocking, and their corresponding stresses versus allowable stress values.
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