TXX-6625, Interim Deficiency Rept CP-85-19 Re Design Requirements & Documents for safety-related Plant Conduit & Conduit Supports.Initially Reported on 861021.Revised Calculation Based on Effective Thread Dimension.Next Rept by 871009

Interim Deficiency Rept CP-85-19 Re Design Requirements & Documents for safety-related Plant Conduit & Conduit Supports.Initially Reported on 861021.Revised Calculation Based on Effective Thread Dimension.Next Rept by 871009

ML20237H194
Person / Time
Site:	Comanche Peak
Issue date:	08/12/1987
From:	Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-85-19, TXX-6625, NUDOCS 8708170100
Download: ML20237H194 (2)

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Log # TXX-6625 . 1 File # 10110-E E 903.11

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filELECTRIC MMam G. CoumH Emstive Vice Presidetrt August 12, 1987 U. S. Nuclear Regulatory Commission Atto: Document Control Desk Washington, D.C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NS. 50-445 AND 50-446 CONDUIT SUPPORT SPANS SDAR: CP-85-19 (INTERIM REPORT)

Gentlemen:

On October 21, 1986, we notified you by our letter logged TXX-6046 of a deficiency regarding the use of a nonrepresentative sample in . determining typical conduit span calculations which we deemed reportable under the provisionsof10CFR50.55(e).. This is an interim report.to provide additional technical information involving the deficiency and to status corrective actions implemented to date. Our last interim report was logged TXX-6421, .

dated April 30, 1987.

As previously noted in our letter logged TXX-6046, the deficiency in' volves previous design requirements and documents for safety related conduit and conduit supports for Units 1 and 2. This deficiency is concerned with the yield stress (Fy) used to justify the span calculation reflected in the previous design.

Since our last report, we have taken an alternative approach concerning yield stress values and thread section properties used to calculate. conduit stress.

We have determined the lowest published Fy.value for commercially av'ailable steel. This value will be used as the basis for design criteria. The originally calculated thread section property was calculated based on root

! dimension. Our revised calculation is now based on an effective thread

! dimension, thus eliminating the undue conservatism in the area of. thread

! sectional properties. By utilizing this alternative approach, the completion l of our evaluation and the formulation of the required corrective actions have j been delayed. Completion of these activities is now scheduled for August 31, 1987.

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ADOCK 05000445 PDR 400 North Olive Street IB 81 Dallas, Texas 75201 j 'g}q l Q

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TXX-6625

, August 12, 1987 l Page 2 of 2 We anticipate submitting our next report no later than October 9, 1987.

Very truly yours, W. G. Counsil I

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By: [-

G. S. Keeley

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i Manager, NucleaFt"}Mng DAR/gj c - Mr. R. D. Martin, Region IV l

Resident Inspectors, CPSES (3) 1 l