ML20054M551

Part 21 Rept Re Slippage of Raceway Support Bolted Strut Fittings,Initially Reported on 810807.Tests at Seabrook to Obtain Final Allowable Loads for Fitting Configurations Will Be Completed by 821206

ML20054M551
Person / Time
Site:	Seabrook, 05000000, Washington Public Power Supply System
Issue date:	06/02/1982
From:	Sarsten G UNITED ENGINEERS & CONSTRUCTORS, INC.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-82-632-006 PT21-82-632-006, PT21-82-632-6, NUDOCS 8207130576
Download: ML20054M551 (4)

Text

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30 South 17th Street. /, p (7! q M

Post Office Dca 3223 Philadelphia, Pa.19101 '

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June 2, 1982 yy go '/ W Director ONU Office of Tnspcerion and Enforcement U. S. Nuclear Regulatory Commission 60- l 6Q Washine, ton, D. C. 20$55 .

Subject:

10 CFR 21 Report of a Potential Defect Related to Public Service Company of !

New Hampshirc - Seabrook Station and i g ply System - WNP 1 and 4 f

On August 7, 1981, UF.6C submitted a report of a potential:

defect pertaining to slippage of raceway support bolted strut t[trings. On November 13, 1981, UE&C submitted a report to inform ,

you ot the actions taken to date and our progress toward obtaining a satistuctory resolution of the notential defect. In that report ;

we defined the corrective action that would be taken by the Power Divisico of l'nILed Engineers and Constructors Inc. The purpose of thin report is tu provide an updated status of actions taken to date which is enclosed an Attachment 1.

i From Attachment !, ir should be noted that the majority of net ivitiv s eeqitired for WSP 1 have been completed for the cable tray SuppocL l i t t i n c,o . However. progress on conduit support fittings has been significantly affected by the recent decision to defer completion o r Un i t. 1. For these fittings, we are presently investigating the Censibility of a corrective progenm which is compatible with the

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linitallons imposed by the construction delay. For Seabrook, certain tests utill are required to obtaIn final allowabic lands for fitting configurations of minor concern.

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Director June 2, 1982 Of fice of InspecLIon and Enforcement l

l We expect to be able to complete these tests and the I assocInted review and report to you the results, or inform you of '

the status thereof by December 6, 1982.

Very truly yours, l

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. Sarsten ,

Vc President - Power, I GMS:ttm '

Attac!tment cc: Regional Director i

USNRC - Region 1 i

Regional Director i

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ATTACIDfENT 1 BOLTED STRUT FITTINGS SLIPPACE PROBLEM l

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, A. ACTIONS TAKEN NOVEMBER 13. 1981 to DATE j

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1. Superstrut Laboratory testing was terminated in lieu of l' initiation of a complete series of tests at an indepen-dent inboratory.

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'l 2. Independent lahoratory testing of the major and minor concern fittings was initiated at the Franklin Institute Research Labs for the WNP-1 Unit and Seabrook Station.

Testing for the WNP-1 Unit'ftttings has been completed and '.'

testing of the Seabrook Station fittings has begun. The decision to begin with the testing for the WNP-1 Unit and i to be followed by the Seabrook Station testing was based .

upon the tollowing: .

$- m. The initial annessment of Seabrook Station fittings ofl major concern indicated that the fittings installed to; date should be replaced with fittings capable of develop-ing the originsi rated capacity and an engineering direc-tive to backfit all the fittings of wajor concern, was issued.

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- b. A similar assennment of the WNP-1 Unit indicated that l

!! hack-fitting would be required for less than 5% of thei.

i supports and therefore, back-fitting would be limited to 3 uuly a small u uu&e r of cases. ,

l 3. For the WNP 1 Unit, the laboratory tests have been completed and confirm that the load reduction factor of 0.5 utilized to ,

4 assess the bolt slippage deff etency, is adequate.. A detailed review of cable tray support fittings was performed on 900 -

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supports of a total 3300. A review (still to be checked) has . i U been performed on an additional 1800 supports which confirms. ,

that less than 5% of the supports may require back-fitting as ,

originally estimated.

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ATTACHMFNT 1 i (Continued) l I

The conduit supports have not undergone a detailed review '

because of the nmall nirmher of supports installed with the i potentially defective strut nuts and also because a cursory '

review indicated that significant conservatism was-used in l the design criteria which rendered these supports adequate  !

with respect to the .5 load reduction factor.

i All cable tray and conduit support fittings currently in-stalled are being buf1t with only Unistrut nuts. <

' 4.- For the Seabrook Station, the laboratory tests for strut fittings of major and minor concern, is now in progress at the Franklin Institute Research Iaboratories, i

All currently installed supports are being built with l only Unistrut nuts and fittings with welded corner seams.

B. RFEATNTNG.ACTI.ONS Tp Bf TAKEN i For the WNP-1 Unit, all the remaining cable tray supports will

• undergo detailed review for the fittings of major and minor concern i by December 6,1982.

s 'The program to address those conduit support fittings with potentially defective strut nuts is presently being re-evaluated in view of the.

.' recent decision to defer construulivu af UAit 1. C6natraints imposed on engineering budget and feasibility to ohtain adequate as-built! data b

are being taken into account in order to formulate a corrective program #

and identify a realistic completion date. {

FortheSeahrookStationcabletrayandconduitsupports,thefithings of major concern installed prior to the implementation of the installa-

- tion of Unistrut (or proven equivalent) nuts will be retrofitted to . -

assure that the original design load capacity is achieved. In addition, all fittince of maior concern containine unwalded corner seams will be

( replaced with fittings containing welded corner seams. ,

Teating of the fittings of minor concern will continue and the test utilized to assure the adequacy of all fittings of minor concern.:

Any required retrofitting or modification will be completed- prior!

to plant start up.

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