ML20087L203

Final Deficiency Rept U-34 Re Pipe Clamp Interference W/Rod End of Rigid Sway Strut Assemblies Supplied by Corner & Lada.Initially Reported on 810813.Rework Plan PV-14 Implemented to Repair Sway Strut Assemblies Onsite

ML20087L203
Person / Time
Site:	Callaway
Issue date:	03/16/1984
From:	Schnell D UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
U-34, ULNRC-770, NUDOCS 8403270079
Download: ML20087L203 (9)

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VUNION ELECTRIC COM PANY ISOS GRATIOT STREET

, ST. Louis Missoums

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March 16, 1984 ~U =U '"a*=**'

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Mr. Jars $IG Keppler

' Regional.iAdministrator ..

,,' U.S.LNuclear, Regulatory Commission Region III' \ ,

. 799 Roosevelt' Road V . Glen' Ellyn, IL 60137, ULNRC-770

Dear Mr. Keppler:

FINAL L10 CFR 50.55 (e) REPORT NO. U-34 V

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CALLAWAY PLANT

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'On.Augnst:13L 1981' Union Electric informed Mr. J. E. Konklin

.;f of the NRC Region III of.a potentially. reportable'significant m[~

deficiency concerning an interference between the ears of a.

Corner & Lada pipe clamp and.its nating size 5. sway strut paddle.

This interference'potentialy reduced the available cone of n 4 . movement to less than 10 degrees as required by design s; specifications. Inadequate cone of movement could potentially

. prevent accommodating' required thermal and s'cismic loads and W result in overstressing safety-related piping or adjacent y a,.Lsupports.

- ,/ . Accordingly,sa. rework plan was established and implemented 7'- . to inspect and repair Corner & Lada sway: struts at_Callaway. The 0 .

' rework plan called for a ' sample ' inspection of all ' sizes of Corner c

. & Lada sway struts for cone - of rotation' movement and established p guidelines for the: repair or replacementiof any defective struts.

lr ~ The physical rework was essentially completed by I'ebruary,1982, e '

The attached report. reflects. Union Electric's final report

'on this deficiency.- Subsequent to the original rework activities

,4; it.was judged necessary to perform additional' data searches and

inspections consistent with the original rework plan criteria in

" orderito reconcile the original ~ rework plan data. We acknowledge

- the; protracted: time period between identification and this submittal; however, until'recently thb. data was not in a

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completed form suitable for' final analysis. In addition, this

,$ c < deficiency has'beensthe subject offreview:and discussion with an;

't . NRC inspector who1was updated ;as to our ' ongoing corrective

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action. ~ Construction and testing activities also served to protract some inspection activities.

Very truly ours, IT Donald F. Schnell JJS/glp Attachment-cc: J. E. Konklin, NRC Region III Richard DeYoung, Director I&E NRC Resident Inspectors, Callaway Plant (2)

Missouri Public Service Commission 4

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.i FINAL REPORT s,

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• 101.CFR 50.55(e)

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, - t s OD P,ipe ' Clamp Intierterence J J

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~ The 5tod' End of' the Rigid:.- Sway Strut Assemblies D ff j by V

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SUMMARY

OF CONTENTS 1.0 Introduction

2.0 Description of Reportable Deficiency-

-3.0 Analysis ~of Safety-Implications

' 4.0 -Corrective' Action r

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10 CFR 50.55(e) - Final Report

1.0 INTRODUCTION

This final report is submitted in accordance with the requirements of 10 CFR 50.55(e) to describe the corrective action taken to resolve a generic deficiency related to an interference between the pipe clamp and rod end of Corner &

Lada rigid' sway strut assemblies.

On August 13, 1981, the Union Electric Site Quality Assurance Group filed a preliminary report regarding this deficiency to Mr. J. E. Konklin of the NRC Region III Office. Nonconformance Report 2SN-4371M documented an interference in a size 5 sway strut assembly, I.D. Number 2-EG09-C008/232. It was observed that the 12 degree cone of movement certified in the supplier's Load Capacity Data Sheet to accommodate thermal and seismic loads was not achievable at the clamp end of the assembly. An investigation disclosed that the problem was due to improper i

fabrication of either the clamp or paddle, or due to excessive weldment in a non-structural weld on the sway strut paddle.

A total of 65 sway struts-(of 224 inspected) required rework or replacement by Corner & Lada to eliminate the

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interferences. Suitable corrective action was taken by

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Corner &;Lada to preclude future interference problems.

2.0 DESCRIPTION

OF REPORTABLE DEFICIENCY

- The size 5 Corner & Lada rigid sway strut in question was

-intended to be employed in a safety-related piping system.

' The manufacturing features which. contributed to.the interference _between the pipe clamp and rod end of the sway strut was common to all sizes of sway-struts supplied by

- Corner /& Lada. The interference noted would potentially not permit the required thermal and seismic movement for safety-related pipe sections.

3 '. 0 . ANALYSIS OF SAFETY IMPLICATIONS Rigid' sway. struts. employed in piping systems'must support the pipe under various loadings such as weight, thermal, and seismic,;ete.- The sway strut must also permit motion of the-piping transversely' perpendicular.to either the end bracket or the pipe-clamp.- This is-achieved byfallowing a 12-degree cone of. travel at'both ends of the sway strut utilizing ball l bushings.. ,

. ,The sway struts in question permitted less than the:fu11.12 4-  ; degree cone of' movement specified in Corner & Lada's load capacity data. sheets. The restriction of pipe movement

could overstress the pipe. The action of the clamp locking

' up:withEthe rod.end of the sway' strut also could have s

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cverstressed any_of the components in the sway strut assembly during piping movement.

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4.O CORRECTIVE ACTION A Rework: Plan (PV-14) was established so that the sway strut assemblies in question could be repaired onsite. The Rework

. -Plan'provided direction'for eliminating any interference at the pipe clamp. All reworked clamp or rod ends were

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- documented by recording.the support number and the type of rework performed. All dimensional changes were also recorded.

The Lead A/E design specification requires a minimum of a 10 degree cone of movement and this was the acceptance criteria employed in the rework plan. If thc available cone of movement was less than 10 degrees, one-of the following

' steps was taken:

1

'l) Replace flat washers withJconical washers to meet the 10 degree cone of movement.

2) Remove excess material ~from'either the rod end or the i

clamp-earsfas required to_ meet the 10 degree cone of movement.

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3) ~ Replace the clamp.

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1 - 4) Use-As-Is based.upon a Lead A/E determination that the cone of movement for the strut in question was adequate

.to meet: design movement.

Tne-following plan was used.to sample other size C&L

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assemblies employed at Callaway-for the available cone of movement.

1) All size'5 struts were inspected.

2) .At'least 10 samples were examined from each of the ffollowing size ranges: 1, 2-3, 4, 6-7.

- 3) ~If.any of the samples inspected did not meet acceptance criteria, an additional-10 samples were inspected from

.thisisize range.

4) If additional nonconformances were detected, a 100%

inspection.of this. size. range was performed. -

- The!following~is a. summary of struts inspected, reworked onsite, or returned to' Corner & Lada'for repair or -

- replacement:-

Number Number Sect'to

!. Strut Number Reworked ' Corner & Lada Number Used

- Size '

Inspected On Site for' Repair by Design 1 10 0- 0' .181-2- 11- 0- 0 305-3 .10 0 0 431-4 134- 43 6 122

'5 -37 18 2 - 30

6. 12 2. 1 12 C, 7- 8 2 0 6

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. Corner & Lada introduced additional controls into the manufacturing process to preclude the release of sway strut assemblies with interferences. In addition, inspections by an-independent _ contractor, Nuclear Energy Services, were used to assure-the remaining supports to be delivered were in' compliance with design requirements.

Based upon the actions taken in Rework Plan PV-14 and the additional controls employed by Corner & Lada to preclude interferences of this type, this problem is considered adequately resolved.

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