ML20054G185

Interim Deficiency Rept 82-04 Re Improperly Tightened Jam Nuts on Certain Structural Steel Bolted Connections in Containment,Initially Reported 820507.Investigation of Parts Utilizing Slip Joint Connections W/Jam Nuts Initiated

ML20054G185
Person / Time
Site:	Clinton
Issue date:	06/11/1982
From:	Gerstner W ILLINOIS POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10CFR-050.55E, 10CFR-50.55E, 1605-L, U-0499, U-499, NUDOCS 8206210225
Download: ML20054G185 (2)

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/LLINDIS POWER COMPANY l f_9f9 I 500 SOUTH 27TH STREET, DECATUR, ILLINOIS 62525 June 11, 1982 i

Mr. James G. Keppler Director, Region III Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

Clinton Power Station Unit I Docket No. 50-461 Construction Permit No. CPPR-137 Potentially Reportable Deficiency 82-04 On May 7, 1982, Illinois Power verbally notified Mr. H.M.

Wescott of a potentially reportable deficiency involving improper-ly tightened jam nuts on certain structural steel bolted con-nections in the containment. Illinois Power is conducting an investigation into this matter, and this letter serves as an interim report per 10 CFR 50.55(e)(3).

The investigation of this matter thus far has focused on the adequacy of design information provided to the constructor (Baldwin Associates) for installation of jam nuts in structural steel slip joint connections. This review has disclosed ambiguities relating to the design drawing notes covering the installation of Jam nuts against high strength heavy hex nuts of the bolted connection. This ambiguity in the details led to misinterpretation of the tightness required of the jam nuts.

It is the designer's intent that high strength heavy hex nuts on structural steel slip joint connections be installed finger tight, allowing the connection to move, with a jam nut torqued snug tight against it, preventing the heavy hex nut from loosen-ing. However, due to misinterpretation of the drawing, both the high strength nut and the jam nuts were installed finger tight.

This situation was found to exist in structural steel connection inside the containment, and in areas exterior to the containment, such as containment gas control boundary, personnel walkway and block wall stiffening columns. Many of the affected connections were inspected and ace,epted for use.

The investigation of this matter continues into other poten-tial areas of deficiency, auch as piping / mechanical, electrical and HVAC hanger auxiliary support steel utilizing slip joint connections with jam nuts. We anticipate that we will require 8206210225 820611 PDR ADOCK 05000461 S PDR JUN 16 E02 j; , '

.. J.G. Keppler June 11, 1982 lIRC l Page 2 l approximately ninety (90) days to complete our investigation in these areas. At such time, we hope to be able to provide further details and conclusions regarding the reportability of this potential deficiency.

Very truly yo rs, 6WP n W.C. Gerstner Executive Vice President cc: H.H. Livermore, NRC Resident Inspector Director, Office of I&E, Washington, DC Director of Quality Assurance Illinois Department of Nuclear Safety