ML20070E426

Interim Significant Deficiency Rept SD 413-414/82-23 Re Violation of Approved Const Procedures for Mixing & Placing Sikatop 122 During Drill Hole Repair.Initially Reported on 821108.Test Program Initiated.Final Rept Due by 830506

ML20070E426
Person / Time
Site:	Catawba
Issue date:	12/08/1982
From:	Tucker H DUKE POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8212170256
Download: ML20070E426 (3)

Text

I DUKE POWER GOMPANY P.O. ISOX 33180 CHAltIJFTTE. N.G. 28242 IIAI.H.Tt:CKER Trt.EsanoNE WMRPSFNtDFW1 (70 8) 373-4N)t exaram revoewm..a Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission o

Region II o

101 Marietta Street, Suite 3100 lo Atlanta, Ger91a 30303 g

7 Re: Catawba Nuclear Station v

Units 1 and 2 C

Docket Nos. 50-413 and 50-414 cp

Dear Mr. O'Reilly:

Pursuant to 10 CFR 50.55e, please find attached Significant Deficiency Report SD 413-414/82-23.

Very truly yours, dk C

Hal B. Tucker RWO/php Attachment cc: Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. P. K. Van Doorn NRC Resident Inspector Catawba Nuclear Station Mr. Robert Guild, Esq.

Attorney-at-Law P. O. Box 12097 Charleston, South Carolina 29412 Palmetto Alliance 2135 Devine Street Columbia, South Carolina 29205

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REPORT NUMBER: SD 413-414/82-23 REPORT DATE:

December 8, 1982 FACILITY:

Catawba Nuclear Station - Units 1 and 2 IDENTIFICATION OF DEFICIENCY: Approved Construction Procedures for mixing and placing SikaTop 122 were violated during repair of abandoned drill holes.

INITIAL REPORT: On November 8,1982, J. Bryant, NRC Region II, Atlanta, Georgia was notified of the deficiency by W. O. Henry, I. W. Pearce and J. A. Lee of Duke Power Company, Charlotte, North Carolina.

COMP 0NENT AND/0R SUPPLIER: Abandoned drill hole repairs made with SikaTop 122 from the Sika Corporation.

DESCRIPTION OF DEFICIENCY:

Concrete expansion anchors are often used to attach supports for pipe hangers, cable trays, etc., to vertical and horizontal concrete surfaces. These anchors transfer shene and tensile loads from the attachments to the concrete structure and must be embedded to specified minimum depths in order to develop their full capacities. Occasionally during installation, reinforcing steel or other interferences are encountered before a hole of sufficient depth can be drilled.

When such cases occur, the holes are abandoned and repaired in accordance with approved construction procedures. Once the repair material has cured for a specified period of time, new anchor locations are selected, new holes drilled, and anchors installed to the required depth. Location tolerances for supports often necessitate that anchors be located partially in or near these repaired

holes, One of the materials approved for repairing abandoned drill holes is SikaTop 122 from the Sika Corporation. This material is a two-component cementitious system generically classified as a latex modified mortar.

Construction procedures require that this material be mixed and placed in accordance with the manufacturer's instructions. The material was approved for use on April 30, 1982, and was the material typically used to repair abandoned drill holes after that date.

During drilling of holes for an anchor in the Auxiliary Building it was necessary to partially drill into an abandoned drill hole which had been repaired with SikaTop 122. The repair material was found to be weak and would not support torquing of the anchor to required load. QA personnel investigated the anchor and determined that Construction personnel making repairs were not following approved construction procedures for mixing and placing SikaTop 122.

Construction personnel indicated that they normally used a quantity of Component A required to achieve a dry pack consistency when mixed with Component B, instead of using the quantity specified by the manufacturer.

Nonconforming item report 15679 was initiated and Duke Power reported the deficiency to the NRC, Region II, on November 8, 1982.

ANALYSIS OF SAFETY IMPLICATIONS:

Anchor capacity could potentially be adversely affected if the anchor is located partially in or near repairs made with SikaTop 122 mixed and placed at a dry pack consistency.

a.

CORRECTIVE ACTION:

A test prograrr has been initiated to determine the quality of repair that will result with SikaTop 122 mixed and placed at a dry pack consistency. Several drilled holes will be dry packed with SikaTop 122 simulating actual field repairs.

Anchors will be located in the repaired rreas and axially loaded to failure to detennine the influence that a repair will have on the capacity of an anchor.

Also, cube specimens will be cast and tested to detennine the compressive strength characteristics of SikaTop 122 when mixed and placed as a dry pack.

A second test program has also been initiated to verify within a 95% confidence level that of the anchors installed since April 30, 1982, less than 5% could experience a reduction in capacity as a result of a defective repair. A list of hangers whose anchors were possibly installed in or near repairs made with SikaTop 122 has been compiled. A sample population will be selected from this list by use of a random numbers table. At least one anchor from each hanger that is accessible will be selected for test. The test anchors will be loaded by a calibrated center-hole hydraulic jack to 125% of their design capacities.

The inability of an anchor to hold this load shall constitute a failure. A minimum of seventy-four anchors will be tested.

The test programs are underway and will require several months to complete. A final report will be submitted by May 6, 1983. Construction personnel involved in repair have been retrained to insure that future repairs made with SikaTop materials are in accordance with manufacturer's instructions and Construction Procedures.