ML20062L655

Part 21 Rept & Second Interim Deficiency Rept Re Incorrect Installation of Backshells on Connectors Used on Cable Assemblies Supplied by Ge,Initially Reported 800912.Util Reviewing Vendor Tests.Final Rept Expected by 810626

ML20062L655
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
REF-PT21-81-346-000 10CFR-50.55E, AECM-81-40, PDR-80-55, PT21-81-346, PT21-81-346-000, NUDOCS 8102170052
Download: ML20062L655 (3)

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Helping Build Mississippi

' ' ' - - P. O. B O X 16 4 0. J ' C K S O N. MISSISSIPPI 3 9205

1. ^M,5$^8ffdf January 20, 1981 Office of Inspection & Enforcenent U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.

Suite 3100 Atlanta, Georgia 30303 Attention: Mr. J. P. O'Reilly, Directer

SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Decket Nos. 50 416/417 File C:60/15525/I5526 PD-30 '55, Status Report No. 2, FOCC Cable Assemblies - Connector Ext enders 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 Pctentially Reportable Defi-ciency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concerns the inccrrec: 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-tertine reportability under 10CFR50.55(e) and 10CFRM. Our status report is attached. We expect to determine final reportability by June 26, 1981.

Yeurs truly, gy J. F. McGaughy, Jr.

CWH:st Attachment cc: Mr. N. L. Sta=pley ctor Stello, Director Mr. G. B. Taylor Mr. R. B. McGehee Div. of Insp. & Enforcement South Miss. Electri:

Mr. T. B. Conner U. S. Nuclear Reg. Comm. Power Association Washington, D.C. 20555 P. O. Box 1589 Hattiesburg, MS 39C Member Middle South U:ilities System

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Attechment to AECM-81/40

• ' ' Paga 1 of 1 STATUS REPORT ':0. 2 TOR PD-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 engage =ent joining the connector backshell with its Sunbank extension. Examples of systems affected are the Neutron Monitoring Systes (CSI) and the Nuclear Boiler System (B21).

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

1. The cause, including the ex:ent of the problem;

2. Corrective action to be taken;

3. Action to preclude recurren:e;

4. Effect on the safety of plant operations.

Our decision as to reportability under IC:TR50.55(e) and 10CFR21 will be based on the above items.

III. Status of Proposed Resolution The NSSS vendor perforned a special quality study on mismatch of threads-cable connectors to Sunbank :dap:ers in order to deter-mine the effect on safety. Quality cat :1 inspectors visually inspected all panel and terminatien :abinet connectors. 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 vere Cannon connector -

size 20. Bending moment tests vere perfer=ed on five (5) samples of the mismatched combinations a assure :cmpliance with MIL-C-5015 G. strength specifications. The required bending moment was applied at 90 intervals on each sa:;le 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 Delav in Final Report The review and evaluation of vender study is not complete.

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

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