ML20077A316

Interim Deficiency Rept Re Greater than Allowable Transverse Sheer Stresses in Concrete Beam/Cooling Tower Wall.Initially Reported on 830301.Mods to Strengthen Wall Completed.Final Rept by 830613

ML20077A316
Person / Time
Site:	Seabrook
Issue date:	07/15/1983
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8307220279
Download: ML20077A316 (2)

Text

y SEmM STAM Enginoming Office:

lPUE5LIC Companyof New SERVICE Hampshw e 1671 Worcester Road Framinoham, Massachusetts 01701 (61'7 ) 872 - 8100 July 15, 1983 SBN -535 T.F. Q2.2.2 United States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406 Attention: Mr. Richard W. Starostecki, Director Division of Project and Resident Programs Refe rences : (a) Construction Permit CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) Telecon of March 1,1983, A. L. Legendre (YAEC) to Richard W. Starostecki (NRC Region I)

(c) Telecon of March 3,1983, A. L. Legendre (YAEC) to Ed Greenman (NRC Region 1)

(d) PSNH Letter, dated March 29,1983, " Interim 10CFR50.55(e)

Report; Cooling Tower Wall / Concrete Beam Transverse Shear Stress," J. DeVincentis to R. W. Starostecki

Subject:

Interim 10CFR50.55(e) Report; Cooling Tower Wall / Concrete Beam Transverse Shear Stress

Dear Sir:

In Reference (c), we filed an Interim 10CFR50.55(e) Report regarding the structural design deficiency affecting certain walls and concrete beams in the cooling tower.

Description of the Deficiency Two general areas of the cooling tower structure were reported to have greater than allowable transverse shear stresses. A further review of these areas indicated that the concrete beams running north and south, which support the tile fill, are not overstressed. Also, the south wall of the cooling tower was found to be within the acceptable stress limits because of the fill concrete placed right against the wall. The deficiency at the lower portions of the north wall of the cooling tower basin related to transverse shear overstress was confirmed. The modifications required to strengthen this wall is corplete and documented on engineering change approvals (ECAs 014146D, 014182C, 014185B, 014199r, and 014224B). These ECAs have been signed off as work completed.

gDRADOCK307220279 830715 S 05000443 PDR I D

.p United States Nuclear Regulatory Commission July 15, 1983

-Attention: Mr. Richard W. Starostecki . Page 2 Analysis of Safety Implications Had titis design deficiency not been revealed before plant operation. the area of the tower structure in question would- be overstressed if all design loads, including seismic loads, were applied. Since the ultimate. strengths of the portions of the structure in question will not be exceeded or approached, gross structural failure and/or collapse would not occur.

Corrective Action Taken The additional strengthening required to eliminate the overstress has a been engineered and the design has been finalized. The incorporation of the design change has been completed.

~

A review for transverse shear in exterior walls of all Seismic Category I structures has been performed. This work is completed and no additional concerns were identified.

We will submit.a final report to Region I by August 16,.1983 upon completion of our verification that the engincaring and strengthening of the cooling tower structure has been adequately completed.

Very truly yours, YANKEE ATOMIC ELECIRIC COMPANY s b J. DeVincentis Project Manager MH0/pf cc: Atomic Safety and Licensing Board Service List Director, Office of Inspection and Enforcement U.S.. Nuclear Regulatory Commission Washington, D.C. 20555-

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