ML20058L424

Forwards Request for Addl Info Re Spent Fuel Pool Rerack Amend.Response to Items Should Be Submitted by 900820

ML20058L424
Person / Time
Site:	Crystal River
Issue date:	07/31/1990
From:	Silver H Office of Nuclear Reactor Regulation
To:	Wilgus W FLORIDA POWER CORP.
References
NUDOCS 9008070207
Download: ML20058L424 (4)

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i July 31,1990  !

-Docket No. 50-302 Mr. W. S. Wilgus Vice President, Nuclear Operations Florida Power Corporation ,

ATTN: Manager, Nuclear Operations Licensing P.O. Box 219-NA-21 Crystal River, Florida 34629

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON SPENT FUEL POOL RERACK AMENDMENT ,

During review of your proposed fuel pool rerack amendment, the Structural and Geosciences Branch found that additional information will be required. ,

Enclosure 1 details the information necessary for the staff to complete its review. I In order to meet our review schedule, we will need a response to these items by August 20, 1990. If you have any questions, please do not hestiate to contact me.

Sincerely.

Original signed by .

George Wunder FOR Harley Silver, Project Manager  !

Project Directorate 11-2 '

Division of Reactor Projects 1/11 ,

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cci M . A. H. Stephens State Planning and Development l General Counsel Clearinghouse Florida Power Corporation Office of Planning and Budget MAC - ASD P. O. Box 14042 Executive Office of the Governor i The Capitol Building St. Petersburg, Florida 33733 Tallahassee, Florida 32301 l

Mr. P. F. McKee, Director Chairman Nuclear Plant Operations Board of County Commissioners Florida Power Corporation Citrus County P. O. Box 219-NA-2C 110 North Apopka Avenue Crystal River, Florida 32629 Inverness, Florida 32650

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Mr. Robert B. Borsum Mr. Rolf C. Widell, Director J Babcock & Wilcox Nuclear Operations Site Support Nuclear Power Generation Division Florida Power Corporation 1700 Rockville Pike, Suite 525 P.O. Box 219-NA-21 Rockville, Maryland 20852 Crystal River, Florida 32629 Senior Resident Inspector Mr. Gary L. Boldt Crystal River Unit 3 Vice President, Nuclear Production U.S. Nuclear Regulatory Commission Florida Power Corporation 15760 West Powerline Street P. O. Box 219-SA-2C Crystal River Florida 32629 Crystal River, Florida 32629 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street N.W., Suite 2900 Atlanta, Georgia 30323 Mr. Jacob Daniel Nash Office of Radiation Control Department of Health and Rehabilitative Services 1317 Winewood Blvd.

Tallahassee, Florida 32399-0700 Administrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304

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e ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION CRYSTAL RIVER 3 RERACK List of Questions I

1) It is stated that the nonlinear modal superpostion method was developed to l analyze nonlinear structural dynamics problems involving impact between com-ponents and Coulomb friction. Equation (8) in the submittal (page 3-16, ,

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. Letter from G. Boldt of Florida Power Corporation to NRC, " Technical l

Specification Change Request No. 175," October 31, 1989) provides a means for approximating the nonlinear term Q by Taylor series with respect to i time. The term Q may be in terms of the unknown variable x, representing i

displacement, whereas terms in Eg (8) seem to indicate it is a function of time. Assass whether Eq(8) is correctly presented and demonstrate that mixed variables are correctly treated. Provide a reference for such expansion. Normally, function f(x) is expanded in terms of x.

2) Impact implies that there is a gap between support and member. It means that Q is either piecewise linear or a jump function (discontinuous) not having higher derivatives. Please discuss with a quantitative example how this dif ficulty is overcome. Indeed, the function Q is required to be an analytical function where existence of all the derivatives are assured.

3) In the submittal, page 3-16, it is stated that the uncoupled equations are integrated analytically to eliminate numerical damping or frequency distor-tion during integration. Provide a discussion of the statement by means of a simple example with nonlinear spring and gap. Demonstrate how such distortions are eliminated by nonlinear modal superposition.

4) It is stated that tne nonlinear model was run for the bounding cases which account for the variation of parameters such as the friction coefficient (0.2 and 0.8) and Region 1 and Region 2 rack structure. The results from these runs include the fuel-to-cell impact loads, support pad load, fuel rack structure internal loads and moments, support oad lift-off, fuel rack sliding, and structural displacements. Provide corresponding values of max-imum fuel and rack stresses and times for liftoff and rack sliding to each of the bounding friction values of 0.2 and 0.8. Discuss the cross sensi-tivity study, for instance, between Taylor expansion time step variation with varying friction coefficients (0.2 with at = 0.001 and at = 0.0001 and 0.8 with at = 0.001 and at = 0.0001) and see how much stresses and lift time change. If a cross sensitivity study is judged unnecessary, explain why not.

5) Discuss the bases for the selection of the range for the rack sliding friction coefficients. It is generally observed that sliding friction coefficients are a function of velocity, thus making the damping term nonlinear. This nonlinear term in damping does not appear in your derivation. Discuss why it does not. If a simplifying assumption is applied for computational con-venience, discuss how such approximations affect the final results in terms of the discussion provided in question (6). If nonlinear damping is im-plicitly included in your derivation, discuss the stability of the solution as is done in reference 4.

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6) The submittal states, "The number of terms that can be included in the Taylor series is det;rmined by the continuity of Q and its time derivatives. The more the number of terms, the larger the allowable integration time step."

It appears that you already have a relationship between the number of terms in the Taylor series and the size of the time step. Please provide the derivation of the relationship. Relate this relationship to the error propagation as a means of ille:? rating the error bound (or approximation).

Estimate of error propagation and its bound has to be established for the reason stated in reference 1. Reference 1 also provides an example as to how this is done in certain cases. One may find the importance of consid-ering error bound in references 2 and 3 especially for complicated and nonlinear cases.

7) Discuss how the 24" drop distance is arrived at (page 3-2).

8) With' espect to page 3-12, provide the bases for using 15% fuel assembly impac1 damping assumption by means of the already available experimental data and discuss how the data are applied in the analysis model (e.g.,

consistency of assumptions made in the analysis and corresponding experi-mental parameters).

9) Dir. cuss.how hydrodynamic mass is applied on the spent fuel pool wall design a:ed the basis thereof.

List of References

1) Issacson, E., and Keller H. B., " Analysis of Numerical Methods" John Wily

& Sons, New York, 1966.

2) Warburton, G. B. "Asse:ement of Error in the Newmark Method in Structural Dynamics," Earthquake Engineering and Structural Dynamics," April 1990.

3) Rall, L. B. , " Computational Solution of Nonlinear Operator Equations" R. E. Krieger Co. ,1979.

4) Stoker, J. J., " Nonlinear Vibration," Interscience, Second Edition, 1966.

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