ML20196G335

Forwards Revised Response to Integrated Design Insp D4.3-9 Noted in Insp Repts 50-327/87-48 & 50-328/87-48.List of Commitments Also Encl

ML20196G335
Person / Time
Site:	Sequoyah
Issue date:	03/02/1988
From:	Michael Ray TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20196G339	List: ML20196G335
References
NUDOCS 8803080130
Download: ML20196G335 (4)

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dTNNESSL'E 1/ ALLEY AUTHORITY CHAvrANOOGA TENNESSEE 374ot 5.~l.1053 Lookout Place s

MAR 21988 u.

II.S. Nuclear Regulatory Co.mntsrion ATTl;: Document Control 8)esk Washington, D.C.

73555 Gentlemen:

In the l'attser of

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Docket Nos. 50-327 Tennesset Valley 'suthority

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50-328 4

SEQUOYAH N ?'JLIIAR PLANT (SQN) - INTDntATED DESIGN INSPECTION (IDI) - NRC INSPECTION REPORT ROS. 50-327/87~40 and 50-328/87-48

,7.ncicsure 3 provides TVA's respon c to IDI item D4.3-9. provides a list of ' onnitor.ntu being mad 2 by TVA in this submittal.

It is our underctandng thct, the revised responsa provided herein completes TVA's

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actionc on this item for SQN unit 2 restart.

If you have any questions, pleaun telephone D. L. Williams at (615) 632-7170.

Very truly yours.

TENNESSEE VALLEY AUTHORITY o/

II. J. R y, Dohuty leector Nuclear Licensing and Regulatory Affairs Enc.losures cc: See, sage 2

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8803000130 880302 1

PDR ADOCK 05000327 G

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.g An Equal Ooportunity fimployer N

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.U.S. Nuclear Regulatory Commission

}g Enclosures cc (Rnclosures):

Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323' Mr. C. G. Zech,' Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 i

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ENCLOSURE 1 SEQUOYAH NUCLEAR PLANT ITEM NUMBER:

D4.3-9 TITLE: Masonry Block Wall Calculations I

SUMMARY

OF ITEM:

Calculations for the evaluation of block walls for IE Bulletin 80-11 could not be located.

CLASSIFICATION:

Documentation i

SUPPLEMENTAL RESPONSE:

In order to verify the adequacy of the masonry walls to meet NUREG 0800, i

Section 3.8.4, Appendix A (NRC criteria) allowable stresses, the activities listed below have been completed.

(1) Evaluation of nine "worst case" reinforced masonry wall groups by the unit strip method.

The reinforced masonry walls in the diesel generator, auxiliary and control buildings were reviewed for wall elevation, height, thickness, reinforcement and wall support condition. Using these attributes, nine worst case wall groups were selected that cover the various buildings and f

floor elevations. These wall groups were evaluated for the following governing loading combinations from TVA design criteria SQN-DC-V-1.1.1:

Case II D+L+E i

Case III D+L+Wr l

Case VI D + L + E' + Pa + Y As a result of this evaluation, all nine wall groups have been determined to meet NRC design criteria allowables for Cases III and VI for masonry

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flexural compressive stress and shear stress, and for reinforcing stress.

Eight of the wall groups meet the NRC criteria allowable stresses for the i

one-half SSE load combination (Case II).

The other wall group, however.

exceeded the allowable masonry flexural compressive stress for Case II (539 lb/in* versus 445 lb/in' allowable). This wall group meets the NRC allowables for masonry shear stress and reinforcing stress. This wall group will be further evaluated after restart of SQN unit 2 to ensure compliance with the NRC criteria for the one-half SSE load combination.

(2) Evaluation of nine reinforced masonry walls for effects of openings and penetrations.

In selecting the walls, the drawings were reviewed to identify walls and a walkdown of the walls was conducted to identify nine "worst DNE4 - 2818Q NTB - 2/27/88 r

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ITEM NUMBER:

D4.3-9 SUPPLEMENTAL RESPONSE:

(Continued) case" walls in the auxiliary and control buildings. This review l

considered wall height, elevation, number and relative location of openings and cumulative effects of attachment loadings. The walls were then evaluated for the appl 8. cable loading combinations considering the effects of the openings, attachment loadings, and vertical load effects.

t The calculations are provided in attachment 1.

The results of this evaluation demonstrate that all walls meet NRC design criteria allowable stresses for the SSE (Case VI) and tornado depressurization load combinations (Case III). Four of the walls, however, exceeded the NRC criteria allowable stress for masonry flexural compressive stress for the one-half SSE load combination. These walls meet the NRC criteria allowables for masonry shear stress and reinforcing stress. They will be further evaluated after-restart of SQN unit 2 to ensure compliance with the NRC criteria for the one-half SSE load combination (Case II).

i While performing field walkdowns for the above evaluations of the l

reinforced masonry walls, TVA identified restraints at the top of some of the walls that had not been installed as required by the drawings.

CAQR j

SQP880177 has been issued to document this condition and the following corrective actions are in progress:

All affected reinforced masonry walls were walked down to verify the presence of the top restraints.

Fifteen walls were identified as needing further evaluation as a result of missing top restraints.

I The walls which have missing restraints were evaluated for their i

inplace condition to ensure that they meet NRC criteria allowable stresses.

Walls that do not meet NRC criteria allowable stresses for Load Cases III and VI will have the top restraints installed before SQN unit 2 restart.

(3) Evaluation of non-Category I unreinforced masonry walls in the Category I I

structures.

The unreinforced masonry walls were evaluated for adequacy in meeting the

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loading combinations of the NRC criteria. This evaluation demonstrated that all walls meet the NRC criteria allowable stresses with the exception f

of the steel restraints on the exterior of one wall in the reactor building. These restraints have a maximum bending stress of 40 ksi, which is well below the ultimate tensile stress of 58 ksi. Thus, the restraints I

will perform their design function of keeping the masonry blocks in

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place.

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Based on the above evaluations, the reinforced and unreinforced masonry walls l

have been determined to be acceptable.

After restart, the walls that did not meet the NRC criteria allowable stress for the one-half SSE load combination (Case II) will be further evaluated through refined analyses and additional i

valkdowns to ensure compliance with the NRC criteria.

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NTB - 2/27/88