ML20112C649

Part 21 & Deficiency Rept Re Inadequate Designed Clamps. Initially Reported on 850314.Spring Disc Washers Required in Clamp Design Shipped to Site,Assembly Drawings Revised to Include Spring Disc & Installation Procedure Made

ML20112C649
Person / Time
Site:	Peach Bottom
Issue date:	03/14/1985
From:	Kortuem J WESTERN PIPING & ENGINEERING CO., INC.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-85-135-000 PT21-85-135, PT21-85-135-000, NUDOCS 8503220058
Download: ML20112C649 (4)

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%t l Nuclear Components Division]Westem Pipi 16d 5) 1485 Yosemite Avenue, San Francisco, California 94124 (415) 822-6464 March 14,1985 Nuclear Regulatory Commission Office of Inspection and Enforcement, Director of Washington D.C., 20555 Submitted By:

John D. Kortuem Quality Assurance Manager Western Piping & Engineering Co. Iac.

Dear Sir; On August 8,1984, Western Piping and Engineering Co. shipped six pipe clamps to the Peach Bottom 2 Nuclear Power Plant, York County, PA on General Electric Company purchase order #205-84D013 Rev 01. The clamps were furnished as part of hanger assemblics H-2, H-10 and H-11 for installation on the recirculation piping system.

The design reports for the clamps specify use of Key Belleville spring dise washers between the clamp beam and the load nut (see attachment A) to compensate for the difference in the rate of thermal expansion between the stainless steel piping and the low-alloy U-Bolt. It has been discovered that: no such spring discs were furnished with the clamps; the requirement for use of those devices was not included in the design data submitted to General Electric; and the information was not included in internal Western Piping manufactt, ring documents.

The omission of the spring dise washcrs was discovered in a design review conducted 1 March 1985 pursuant to a request by General Electric to furnish torque values for the clamp U-Bolts in lieu of pretension values furnished with the original design data. It was not, however, viewed as a critical omission at the time of aiscovery (The spring dise washers are exempt from Code material requirements under NF2121(b) and no certifi-cates of compliance are required). Informal notification of the omission was made to General Electric and our design engineer was consulted to determine the feasability of eliminating the spring discs from the assembly. On 11 March 1985 it was learned that the spring discs were, in fact, critical to the integrity of the clamp and that their omission from the assembly could result in failure of the U-Bolt / Nut threads under operatin[*

conditions. Telephone notification pursuant to the 10 CFR Fart 21 was made on 14 March 1985 to General Electric Company and Mr Allen Johnson, Director of Inspection and Enforcement for the Region V Office of the NRC, apprising them of the problem and advising subsequent ,

submittal of this notification.

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NRC Ltr 3-14-85 Page 2 of 2 Corrective action has been initiated as follows: The spring disc washers required by the clamp design have been procured and shipped to the site. The assembly drawings have been revised to incorporate the spring discs and an installation procedure has been generated to provide instruction for their installation in the clamp assemblies. All revised documentation has been reviewed and approved by Western Piping &

Engineering personnel and ha.= been forwarded to General Electric for their approval and subsequent transmittal to the owner. A complete review of all other designs for pipe clamps furnished to nuclear power plants by this company has revealed that all other clamps intended for use on stainless steel piping were furnished with stainless steel bolts and would not have required spring dise washers to compensate for gross difference in rates of thermal expansion between pipe and clamp bolts.

An internal Western Piping Corrective Action Report, Number W-987-13, has been generated to investigate this incident and determine appropriate recurrence prevention.

Sincerel

-3 John D. Kortuem QA Manager, WP&E cc: Sam Brown, General Electric Co. Purchasing Joe Dyer, General Electric Co., QA Mike Wright, WP&E Project Mgr.

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