ML20003B626

Interim Deficiency Rept,Originally Reported on 800912,re Incorrect Installation of Bachshells on Connectors Used on GE Cable Assemblies.Nsss Vendor Test Results Under Review to Determine Reportability by 810626

ML20003B626
Person / Time
Site:	Grand Gulf
Issue date:	01/20/1981
From:	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-81-40, NUDOCS 8102250054
Download: ML20003B626 (2)

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MISSISSIPPI POWER:&. LIGHT COMPANY

] Helping Build Mississippi Edddhhdaag F. O. B O X 16 4 0 J A C K S O N, M I S S I,SS lP l39205 "W'

iMR Tu'$$tTNEeV January 20, 1981 so-es7-q3Lj

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Office of Inspection & Enforcement 9 U. S. Nuclear Regulatory Commission . pg' 4 Region II 'y /

101 Marietta Street, N.W.

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Cy p f{ Y((3 h, Suite 3100 -

g 4, " g - v 198 J m L-4 Atlanta, Georgia- 30303 ,

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88 Attention: Mr. J. P. O'Reilly, Director s

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416/417 File 0260/15525/15526 PRD-80/55, Status Report No. 2, PGCC Cable Assemblies - Connector Extenders

[ AECM-81/40

Reference:

AECM-80/249, 10/13/80 On September 12, 1980, Mississippi Power & Light Company noti-fied Mr. M. Hunt of your office of a Potentially Reportable Defi-ciency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concerns the incorrect installation of back-shells on connectors used on certain cable assemblies supplied by General Electric. These cable assemblies were supplied for the Power Generation Control Complex (PGCC).

We are reviewing results of NSSS vendor tests in order to de-termine reportability under 10CFR50.55(e) and 10CFR21. Our status report is attached. We expect to determine final reportability by June 26, 1981.

Yours truly, I

gy J. P. McGaughy, Jr. p(

CWH:mt Attachment cc: Mr. N. L. Stampley Mr. Victor Stello, Director Mr. G. B. Taylor Mr. R. B. McGehee Div. of Insp. & Enforcement South Miss. Electric l Mr. T. B. Conner U. S. Nuclear Reg. Comm. Power Association Washington, D.C. 20555 P. O. Box 1589

- Hattiesburg, MS 39401 810225005Y Member Middle South Utilities System

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0FFTCTAL COPY g

Attachment to AECM-81/40

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Page 1 of 1 STATUS REPORT NO. 2 FOR PRD-80/55 I. Description of the Deficiency Certain.PGCC cable assemblies supplied by General Electric were installed incorrectly. An adapter was used to connect fine-threaded extension 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 affected are the Neutron Monitoring System (CSI) and the Nuclear Boiler System (B21).

II. Proposed Resolution Mississippi Power & Light Company is working with the construc-tor to evaluate this deficiency and to make the following deter-minations:

1. The cause, 1,cluding the extent of the problem;

2. Corrective action to be taken;

3. Action to preclude recurrence; 4 Effect on the safety of plant operations.

Our decision as to reportability under 10CFR50.55(e) and 10CFR21 will be based on the above items.

III. Status of Proposed Resolution The NSSS vendor performed a special quality study on mismatch of threads-cable connectors to Sunbank adapters in order to deter-mine the effect on safety. Quality Control inspectors visually inspected all panel and termination cabinet connectors. The res'ults 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 on five (5) samples of the mismatched combinations to assure ecmpliance with MIL-C-5015 G' strength specifications. The required bending moment was applied at 90 intervals on each sample with no thread failures observed. MP&L is currently reviewing the above study for ade-quacy and subsequent determination of corrective action.

IV. Reason for Delay in Final Report The review and evaluation of vendor study is not complete.

V. Final Report Date We expect to file our final report by June 26, 1981.