ML20149D735
| ML20149D735 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/04/1988 |
| From: | Beck J, Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-86-51, TXX-88195, NUDOCS 8802090614 | |
| Download: ML20149D735 (2) | |
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February 4, 1988 U. S. Nucicar Reaulatory Commission Attn: Docutaent Control Desk Washington, D.C.
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SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 ANCil0R BOLTS SUPPLIED BY filLTI SDAR:
CP-86-51 (FINAL REPORT)
Gentlemen:
On July 17, 1986, we verbally notified your Mr. I. Barnes of a deficiency involving anchor bolts supplied by Hilti. Our most recent interim report was logged TXX-88083, dated January 11, 1988. We are conservatively reporting thisissueundertheprovisionsof10CFR50.55(e).
The required information follows.
DESCRIPTION At another nuclear facility, conditions have been identified wherein the anchor bolts supplied by Hilti do not meet average ultimate tensile loads in certain sizes as published by the supplier.
Extensive evaluation of the problem by Hilti resulted in the concern being limited to 1/2 inch diameter Kwik Bolts with design embedments of 3-1/2 inches and larger.
This evaluation has resulted in the issuance of IE Information Notice No. 86-94, "Hilti Concrete Expansion Anchor Bolts," reporting a reduction in ultimate tensile capacity values for the 1/2 inch diameter Kwik Bolts.
These bolts have been used at CPSES and the reduction in ultimate tensile capacity values could have an impact on the integrity of structural designs and installations.
The cause of this deficiency is the reduction of tensile load capacity as determined by the vendor.
This deficiency is limited to Hilti bolt installations with design embedments of 3-1/2 inches and larger.
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TXX-88195 February 4, 1988 Page 2 of 2 SAFETY IMPLICATIONS Reduction of the tensile load capacity for 1/2 inch diameter Hilti bolts could result in the failure of these bolts to adequately anchor safety related equipment during a seismic event.
This issue is conservatively deemed reportable under the provisions of 10CFR50.55(e) due to the extensive evaluation required to establish the adequacy of existing Hilti Bolt installations.
CORRECTIVE ACTION V
Hilti bolt installations will be evaluated for adequacy by tensile testing the
= bolts in CPSES concrete to. determine the ultimate capacity and/or by comparing the revised allowable loads with those used for design.. Based on the results of the. tensile testing, design allowables will be revised accordingly and inclu M i. the applicable design documents.
Any bolts found to be unacceptable during this comparison will be reworked in accordance with applicable project procedures. Ccepletion of this corrective action for Unit I will be completed by April is, 1980. Unit I corrective actions will be implemented prior tc Unit fuel loading.
Very truly yours, W. G. Counsil By:
J./ b Jatin W. Beck Vice President, Nuclear Engineering GLB/grr c-Hr. R. D. Martin, Region IV Resident inspectors, CPSES (3) t...__._
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