A05084, Submits Final Response to IE Bulletin 80-11 Re Masonry Wall Design.Cracks Monitored Over 1-month Span.Review of as-built Wall Before Mods Indicates No Cracks.Mortar Joint Cracks Resulted from Const Process of Installing Mods

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Submits Final Response to IE Bulletin 80-11 Re Masonry Wall Design.Cracks Monitored Over 1-month Span.Review of as-built Wall Before Mods Indicates No Cracks.Mortar Joint Cracks Resulted from Const Process of Installing Mods
ML20153H427
Person / Time
Site: Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date: 02/18/1986
From: Opeka J, Sears C
CONNECTICUT YANKEE ATOMIC POWER CO.
To: Charemagne Grimes
Office of Nuclear Reactor Regulation
References
A05084, A5084, IEB-80-11, NUDOCS 8603030092
Download: ML20153H427 (4)


Text

. .s CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N. CO N N E C TICU T P o Box 270 HARTFORD. CONNECTICUT 06141-0270 T E L E PHONE 20ms-s February 18,1986 Docket No. 50-213 A05084 Office of Nuclear Reactor Regulation Attn: Mr. Christopher I. Grimes Integrated Safety Assessment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:

Haddam Neck Plant Masonry Walt Design,IE Bulletin 80-11 Final Response In a December 31, 1985 letter (I) Connecticut Yankee Atomic Power Company (CYAPCO) provided responses to the Staff's requests for additional information with respect to masonry wall design at the Haddam Neck Plant. CYAPCO advised the Staff that cracking on masonry walls, identified during the October 29,1985 site walkdown, was being investigated.

CYAPCO has investigated this concern and concludes that the mortar joint cracks do not invalidate the previous response to IE Bulletin 80-11. In order to evaluate the impact these mortar joint cracks had on structural integrity of subject walls, the crack locatiors were documented as shown in Figures 1 and 2.

The cracks were monitored over a one month span and the results of this monitoring indicate these cracks are no longer propagating. A review of the as-built wall before modifications does not indicate any cracks. It is therefore postulated that these mortar joint c acks resulted from the construction process of installing the IE 80-!! modifications.

The walls CYTB 1009 and CYTB 1010 both span 19 feet vertically and have both been modified by the addition of vertical steel beams to assure that the walls can span vertically without excessive deformation. Thus, the primary failure mode would be out-of-plane bending. As can be seen from Figures 1 and 2, the mortar joint cracks are shear-type cracks in the lower third of each wall. The crack type and location indicate that the cracks are in an area of low bending i stresses and would not invalidate the assumption that the wall will bend out of plane as a simple beam. CYAPCO concludes that the existence of these cracks does not alter previously performed calculations on these walls, which l demonstrated their adequacy.

0603030092 060210 PDR ADOCK 05000213 O PDR (1)]. F. Opeka letter to C.1. Grimes, dated December 31,1985.

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In an effort to eliminate further concern over the identified cracks, CYAPCO plans to repair these areas to a condition consistent with the remaining portions of the wall. This repair will be monitored to insure the cracks do not reappear.

This completes CYAPCO's response to IE Bulletin 80-11. We trust you will find this information satisfactory.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY S.% .DM J.F.Opeka '

Senior Vice President M

By: C. F. Sears Vice President 1

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