ML20004G049

Status Rept 1 Re Potentially Reportable Deficiency Re GE CR2940 Tandem Block Control Switches,Initially Reported by GE Under Part 21,on 810520.Investigation of Safety Implications in Progress.Final Rept by 811015

ML20004G049
Person / Time
Site:	Grand Gulf
Issue date:	06/22/1981
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
AECM-81-220, PDR-81-26, NUDOCS 8106290052
Download: ML20004G049 (4)

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1 MISSISSIPPI POWER & LIGHT COMPANY l Helping Build Mississippi EdMhklide P. O. BO X 16 4 0. J AC K S O N. MIS SIS SIP PI 3 9 2 05 Tsy,,gg,g.,j" June 22, 1981

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Office of Inspection 5 Enforcement y ' A,  !

g U. S. Nucicar Regulatory Commission Region II -

101 Marietta Street, N.W. C- I -

Suite 3100 Atlanta, Georgia 30303 J 3gi'3.bgCA g 2 g> .

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

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SUBJECT:

Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-4?6/417 File 0260/1557.5/??526 PRD-81/26, Status Report No. 1 CR2940 Tandem Block Control Switches AECM-81/220 On May 22, 1981, Mississippi Power & Light Company notified Mr. Paul Kellogg, of your office, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concerns loose contact blocks in General Electric CR2940 tandem block control switches.

Our investigation into this deficiency has not been completed. Attached is our first status report'. We expect to complete our investigation to determine Jafety implications and the extent of this deficiency and submit our Final Report by October 15, 1981.

Yours truly, Y A -

g J. P. McGaughy, Jr.

KDS:dr ATTACHMENT cc: See page 2 b

2 llI 81062O0 0D Member Middle South Utilities System I

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l Mr. J. P. O'Reilly AECM-81/220 NRC Page 2 cc: Mr. N. L. Staapley Mr. R. B. McGehee .

Mr. T. B. Conner Mr. Victor Stallo, Director .

Office of Inspection & Enforcement U. S. Nuclear Regulatory Commaission Washington, D.C. 20555 Mr. G. B. Taylor South Miss. Electric Power Association P. O. Box 1589 Hattiesburg, MS 39401 1

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bec: Dr. D. C. Gibbs ~

Mr. J. N. Ward Mr. J. F. McGaughy 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. A. Taylor PRD File File O

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Attachment to AECM-81/220 ,

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STATUS REPORT NO. 1 FOR PRD-81/26 I. Description of the Deficiency The General Electric CR2940 tanden block control switches have contact blocks that come loose during shipment. Vibration during a seismic event could cause a contact block to loosen suf ficiently further to inhibit .

proper operation of the switch. Several of these switches are located at GCNS both within and outside the NSSS scope of supply in Unit 1. , _

General Electric Company filed a report on this deficiency under the pro-visions of 10CFR21 with the NRC on May 20, 1981. The investigation into the safety implications for this deficiency at GGNS has not been completed.

II. Approach to Resolution of the Problem The cause of this condition is a design deficiency by General Electric in the tanden block cont ol switches. The extent of the condition is not known at this time. Corrective action consists of inspecting all CR2940 tandem block switches for loose contact blocks, loosening the nuts hold-ing the contact blocks found loose, applying Lock-Tite, and then re-tightening.

III. Status of Proposed Resolution Mississippi Power and Light is currently working with our Constructor and NSSS supplier to determine the safety implications and the extent of this deficiency at CGNS. We expect this investigation to be completed by September 15, 1981.

IV. Reason Why a Final Report Will Be Delayed Our Constructor and NSSS supplier have not completed their evaluations.

V. Date When Final Report Will Be Submitted We expect to submit a final report on or before October 15, 1981.

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