ML20136F124

Safety Evaluation Re IE Bulletin 80-11, Masonry Wall Design. Issues Re Arching Action Theory Resolved

ML20136F124
Person / Time
Site:	Vermont Yankee
Issue date:	11/18/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20136F110	List: ML20136F106 ML20136F124
References
IEB-80-11, NUDOCS 8511220044
Download: ML20136F124 (1)

Text

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< UNITED STATES 8 o,j NUCLEAR REGULATORY COMMISSION g 8 WASHINGTON, D. C. 20555 I s.,*****j

! SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ,

MASONRY WALL DESIGN, IE BULLETIN 80-11 i VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271 INTRODUCTION

By letter dated November 15, 1983, the staff provided a Safety Evaluation i (SE) concerning IE Bulletin 80-11, Masonry Wall Design. The staff concluded that, except for ten walls qualified by the licensee using the

, arching action theory to resist the out-of-plane seismic forces, items 2(b) and 3 of IE Bulletin 80-11 have been fully implemented at the Vermont Yarikee

facility. The SE also included a staff position on the arching action theory and stated that the implementation of this position was required to render the above ten walls acceptable to the staff.

EVALUATION I By letter dated June 28, 1984, the licensee informed the staff of the j results of the reevaluation of the above ten walls. The reanalysis was based on the working stress criteria and the allowable stresses consistent with the ACI 531-79 ' Building Code Requirements for Concrete Masonry I' Structures,' American Concrete Institute,1979, Unifonn Building Code, 1979, and the staff position delineated in SRP Section 3.8.4, Appendix A.

) The above cited reanalysis indicated that all but one of the above ten walls can now be qualified on the basis of the working stress criteria meeting the above cited code requirements. The remaining wall, because of two anchor restraints located on it, is overstressed by the seismic inertia

effects. To reduce these stresses and bring them within acceptable limits, 4

the licensee has committed to either remove or modify, as necessary, one of j the restraint supports and reanalyze the other. The reanalysis will use the refined piping loads and may result in a modification of the support or wall. The needed modifications will be completed in the 1985 refueling outage that started in mid September 1985.

l CONCLUSION Based on the above findings and the licensee's comitments, the staff concludes that the issues regarding arching action theory at Vermont Yankee have been resolved, and there is a reasonable assurance that all safety related masonry walls at Vermont Yankee will withstand the specified design load conditions without impairment of wall integrity or the  ;

l performance of the required safety functions.

1

Principal Contributor: N. Chokshi Dated: November 18, 1985 l

l 8511220044 851118

.gDR ADOCK 05000271 l eDR

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