ML20198A106

Forwards Further Clarification to Confirming That Polar Crane Design Meets FSAR Commitments Re Allowable Stress.Encl Should Resolve Unresolved Item 86-03-02 Identified in Insp Rept 50-424/86-03

ML20198A106
Person / Time
Site:	Vogtle
Issue date:	05/01/1986
From:	Foster D GEORGIA POWER CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
GN-892, NUDOCS 8605200333
Download: ML20198A106 (6)

Text

r-Georgia Ibwer Company Qp@

6 Fbst Office Box 282 Waynesboro, Georg:a 30830 Telephone 404 5549361. Est. 3360 404 724 8114. Ext. 3360

.. 4g o AY - L, D. o. Foster y, .i Georgia '

Power Wce President s I!v soortun e/mtrc s, stem Vogtle Project May 1, 1986 United States Nuclear Regulatory Commission File: X7BD102 Suite 2900 Log: GN-892 101 Marietta Street, N.W.

Atlanta, GA 30323

Reference:

1. Vogtle Electric Generating Plant - Unit 1, 50-424, NRC Report No. 50-424/86-03, Module 8 Structural Steel

2. GPC letter GN-864 dated April 17, 1985 Attention: Mr. J. Nelson Grace Attached is a supplement to Georgia Power Company transmittal, Log GN-864, dated April 17, 1986. The transmittal was forwarded in response to two unresolved items (URI) identified in NRC inspection report 50-424/86-03 regarding Module 8, Structural Steel, reference 1.

l One of the two unresolved items. URI 86-03-02, pertained to design calculation for the polar crane. The response to URI 86-03-02 contained in GN-864 reference 2 provided clarifications on the issues raised by the NRC inspection team.

I The enclosed supplement to GN-864 is issued to further clarify and confirm that the polar crane design meets the FSAR commitments relating to allowable stresses.

Should you have any further questions, please contact us.

This response contains no proprietary information and may be placed in the NRC Public Document Room along with our previous transmittal GN-864.

Very truly y s,

[2hD o

p D. O. Foster MRT/DOF/deg cc: See Attachment 1 1{ b

Attachment 1 cc: U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Victor J. Stello, Jr., Director U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement l Washington, D.C. 20555 J. W. Thompson U. S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, MD 28014 Ms. Melanie A. Miller Division of Licensing Licensing Branch #4 Washington, D.C. 20555 Senior Resident Inspector U. S. Nuclear Regulatory Commission Vogtle Electric Generating Plant B. W. Churchill Shaw, Pittman, Potts & Trowbridge 1800 M Street, Northwest Washington, D.C. 20036 J. E. Joiner Troutman, Sanders, Lockerman & Ashmore Candler Building 127 Peachtree Street, N.W.

Atlanta, GA 30303 D. C. Teper Georgians Against Nuclear Energy 1253 Lenox Circle Atlanta, GA 30306

(

Attachment 1 Page Two cc: William M. Hill NRC-IE (EWS-305)

Building East West / South Towers 4340 East-West Hwy.

Bethesda, MD. 20555 W. H. Rankin Suite 2900 101 Marietta Street, N.W.

Atlanta, GA 30323 R. E. Conway J. T. Beckham. Jr.

R. A. Thomas D. E. Dutton D. S. Read W. T. Nickerson D. T. King K. Wiedner P. D. Rice R. H. Pinson C. W. Whitney J. A. Bailey F. B. Marsh J. L. Vota C. W. Hayes S. H. Freid W. C. Ramsey R. T. Oedamer J. S. Hempstead W. M. Wright R. W. McManus G. C. Bell J. E. Seagraves M. H. Googe H. Walker J. Starnes (INPO)

O. Batum Document Control Project File RR Reading File (Letter Only)

Attachment 2 j Page 1 of 3 Polar Crane Design Calculation In response to the telephone request by the NRC on April 24, 1986, the following clarifications are provided as supplement to Georgia Power Company letter GN-864, dated April 17, 1986.

Conformance to FSAR Paracraph 9.1.5.2.3.1.B The polar crane design is in conformance with the allowable stress criteria specified in FSAR paragraph 9.1.5.2.3.1.B.

In the polar crane analysis, the worst-case load position was determined using modal response spectrum analysis. For this load position, time-history analyses were performed utilizing a nonlinear modal, which accounts for the slack in the rope etc.,

to determine the actual stresses under seismic conditions.

While the modal analysis using a linear model is adequate to determine the worst-case load position, the resulting stress does not represent the true stress condition, since

-nonlinearities such as slack in the rope are not accounted for in the modal analyses. The girder stresses that were discussed in GPC letter GN-864 were from the modal analysis, as requested by the NRC. The intent of that discussion was to demonstrate that the behavior of the analytical model utilized for the modal analysis was appropriate.

The attached table provides a summary of polar crane ccaponent stresses obtained from the time-history analyses for operating basis earthquake (OBE) and safe shutdown earthquake (SSE) load conditions. It can be seen that the actual stresses in the polar crane components meet the allowable stress criteria specified in FSAR paragraph 9.1.5.2.3.1.B.

Diocrepancy Relatino to Load Positions Specified in X4ALO1 The polar crane procurement specification X4ALOl initially did not include the details of the seismic qualification requirements. During the Bechtel Power Management Independent Design Review audit, a broadness review on the use of the proper spectra for equipment qualification identified the need to include details on seismic qualification information in specification X4ALOl. In response to this observation, the load positions were later incorporated into the specification. In the process, the load positions initially proposed by the polar crane vendor, rather than the load positions considered in the

7 Attachment 2 Page 2 of 3 polar crane analysis, were incorporated in the specification.

As explained in GPC response GN-864, the load positions considered in the analysis envelop the governing load positions. Specification X4ALOl is being revised to be consistent with the load positions considered in the polar crane seismic analysis.

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Attachment 2 Page 3 of 3 POLAR CRANE C0ff'ONENT STRESSES Structural OBE Stress (psi) SSE Stress (psi)

Component Computed AlIowable(I) Conuxated AIIowabIe(l) Source Girder midspan (a) Flexure 13,982 22,000 13,183 32,400 Pages C-4, C-10, and (0.6 Fy) (0.9 Fy) C-12 of seismic report (b) Shear (Girder end controls) (Girder end controls) (Bechtel log No.

AX4LOI-46-2).

Girder end (a) Flexure 21,870 22,000 20,764 32,400 Page 4-23 of seismic (0.6 Fy) (0.9 Fy) report for stresses (b) Shear 9,473 14,400 9,881 18,000 and loadings.

(0.4 Fy) (0.5 Fy)

Truck equalizing pin Shear 10,410 17,200 10,860 21,500 Pages 4-8 and 4-9 of (0.4 Fy) (0.5 Fy) seismic report.

Beam equilizing pin Shear 11,420 15,200 11,920 19,000 Page 4-17 of seismic (0.4 Fy) (0.5 Fy) report.

1. Yield stresses (Fy) for the following components are:

Girder 36,000 psi Truck Equilizing Pin 45,000 psi Beam Equilizing Pin 38,000 psi For Fy = 36,000 psi, the allowable stress corresponding to 0.6 Fy is taken as 22,000 psi, consistent with the American Institute of Steel Construction, Inc. (AISC), Appendix A.

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