ML19346A187

Part 21 Rept Re Loose Contact Blocks on CR2940 Tandem Block Control Switches Used in Power Generation Control Complex Panels.Ge Informed Util of Defect & Proper Corrective Action

ML19346A187
Person / Time
Site:	Grand Gulf
Issue date:	05/28/1981
From:	Sherwood G GENERAL ELECTRIC CO.
To:	Stello V NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
REF-PT21-81-442-000 10CFR21, MFN-103-81, PT21-81-442, PT21-81-442-000, NUDOCS 8106050351
Download: ML19346A187 (2)

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GENER AL h ELECTRIC NUCLEAR POWER ,

SYSTEMS DIVISION GENERAL ELECTRIC COMPANY.175 CURTNER AVE.. SAN JOSt!. CALIFORNIA 95125 MC 682, (408) 925-5040 MFN-103-81 0o 0 '

May 28, 1981 y (/ 2 o

U.S. Nuclear Regulatory Connission Office of Inspection and Enforcement p g O 'I)SSl m .d Washington, D.C. 20555 -

g p Attention: V. Stello, Jr., Ofrector S U

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Gentlemen:  % 4

SUBJECT:

10CFR PART 21 REPORTABLE CONDITION CR 2940 SWITCHES This letter is to advise the NRC of a reportable condition per 10CFR Part 21 as reported to your office by C.A. Cameron, Acting Manager Safety Evaluation Programs, on May 20, 1981. The defect is loose ccntact blocks on CR 2940 tandem block control switches used in the Power Generation Control Complex panels supplied to the Grand Gulf -

Project of Mississippi Power & Light (MP&L). This condition was judged reportable on May 19, 1981. Attached is the report of the defect as it applies to the Grand Gulf Project.

General Electric has infonned MP&L of the defect and has informed them of the proper corrective action to take. Since CR 2940 tandem block switches are used in other applications, all BWR owners will be advised of this problem and the corrective action to take.

Very truly yours, fW lenn G. Sherwood, Manager Nuclear Safety & Licensing Operation Attachments cc: V. Stello, Jr., NRC (2 extra copies)

B.H. Greir, NRC Region I l J.P. O'Reilly, NRC Region II l J.G. Keppler, NRC Region III l U. Potapovs, NRC Region IV R.H. Engelken, NRC Region V J.F. McAllister, General Electric L.S. Gifford, General Electric So(I i

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LOOSE CONTACT BLOCKS ON CR 2940 SWITCHES The CR 2940 tandem block control switches used in the Power Generation Control Complex supplied to Grand Gulf Project of  :

Mississippi Power & Light (MP&L) have a defect. The switches have contact blocks that came loose during-shipment to the site. Vibration during a seismic event could cause a contact block to loosen sufficiently further-to inhibit proper operation of the switch. General Electric has issued a Field Disposition Instruction (FDI) advising MP&L to inspect all contact blocks that are found loose; the nuts holding the contact block are to be retightened. l I

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