ML20004F793

Final Deficiency Rept PRD-80/55 Re Incorrect Installation of Backshells on Connectors Used on GE Cable Assemblies, Initially Reported on 800912.Backshell Adaptor Rings Removed.Condition Not Reportable Per 10CFR50.55e

ML20004F793
Person / Time
Site:	Grand Gulf
Issue date:	06/12/1981
From:	Cgaughy J, Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, AECM-80-55, AECM-81-203, NUDOCS 8106220390
Download: ML20004F793 (4)

Text

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l MISSISSIPPI POWER & LIGHT COMPANY

]E Helping Build Mississippi EmblMAMdds P. O. B O X 16 4 0. J A C K S O N, MI S SIS SIP PI 3 9 2 0 5 J^j$Cgdf June 12, 1981

• CD 0

Of fice of Inspection & Enforcement /s

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8 U. S. Nuclear Regulatory Commission degfon II -

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101 Marietta Street, N.W. p 4,H a, 2 0 /S$7 g /

Suite 3100 ,,,

Atlanta, Georgia 30303 "' *8 M/

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Attention: Mr. J. P. O'Reilly, Director -

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-80/55, Final Report, PGCC Cable Assemblies - Connector

' Extenders AECM-81/203 Refe rences : 1. AECM-80/249, 10/13/80

2. AECM-81/40, 1/20/81 On September. 12, 1980, Kississippi Power & Light Company notified Mr. M.

Hunt, of your of fice, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (GCNS) construction site. The deficiency concerns the incorrect installation of backshells on connectors used on certain cable assemblies supplied by General Electric. These cable assemblies were supplied for the Power Gineration Control Complex (PCCC).

We have determined that this deficiency is not reportable under 10CFR50.55(e) or 10CFR21. Cur final report is attached.

Yours truly, J. P. McGaughy, Jr.

EWC:dr ATTACHMENT cc: See page 2 gN 810 6 2 20 39Q Member Middle South Utilities System

4

,JMr. J. F. 0'Reilly AECM-81/203 NRC. Page 2 cc: Mr. N. L. Stanpley-

'Mr. R. B. McGehee Mr.'T. B.~ Conner-

.Mr. Victor Stello.. Director ,

Of fice of Inspection & Enforcement

- U. S. Nuclear Regulator: Commission Washington. D.C. 20S55 Mr. G. B. Taylor .

South Miss. Electric Power Association P. O.~ Box 1589 Hattiesburg, MS 39401 f

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- .-ce, - e. ,, y._

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bec: Dr.'D, C. Cibbs' Me,. D. C. Lucken

--rir. J. N. Ward Mr. W. A. Braun

'Mr. R. Trickovic Mr. J. W. Yelverton Mr. L. F. Dale

' Mr. C. K. McCoy

- Mr.'.T. H. _Cloninger Mr. R. A. Ambrosino . ,

Mr. R.-C. Fron Mr. G..B. Rogers

-Mr. M. R. Williams Mr. L. E. Ruhland *.

Mr. D.;L. Hunt -

Mr. A. C. Wagner Mr. P. Ak Taylor PRD File File b

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'. 'AttachmenttoAECM-81/203

• Page 1 of 1 FINAL REPORT FOR PRD-80/55 I. Description of the deficieng Certain PGCC cable assemblies supplied by General Flectric were instal-led incorrectly. An adapter was used to connect fine-threaded exten-sion pieces to the backshell of Cannon connectors. However, this adapter was incorrectly used with coarse-threaded extension pieces

, manufactured by Sunbank. Cable assemblies with this deficiency appear susceptible to disconnection, since they have less than one thread -

engagement joining the connector backshell with its Sunbank extension.

Examples of systems af fected are the Neutron Monitoring System (C51) and the Nuclear Boiler System (B21).

~

II. Analysis of Safety Implications The NSSS vendor performed a special quality study on mismatch of threads-cable connectors to Sunbank adapters in order to deteraf ne the effect on safety. Quality Control inspectors visually inspectei all panel and termination cabinet connectors for Unit 1. The results of their inspection plus a review of samples of all types of connectors, adapter rings, and Sunbank adapters revealed that the only potentially mismatched threads were Cannon connector size 20. Bending moment tests were performed ori five (5) samples of the mismatched combinations to assure compliant.e with MIL-C-5015 C strength specifications. The required bending moment was applied at 90 intervals on each sample with no thread failure 1 obse rved. The NSSS vendor therefore concluded that the connector assemblies could be "used as is," and that there would be no ef fect on safe operation of the plant. This deficiency does not meet the reporting requirements of 10CFR50.55(e) or 10CFR21.

III. Corrective Actions Taken MP&L decided tc remove the adapter rings for Unit 1. The work has been completed. .

Concetning the preclusion for recurrence, revisions to clarif' the proper use of the adapter ring are currently being processed for the Inspection Instruction IICA-002 and the purchase part drawing (19 B9713) for the Sunbank adapter. Clarifying revisions on the Cable Shop Assembly Ins';ruction Manual and shop QC instructions are now-in place which conteci current shop work.

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