ML20085E777

Interim Deficiency Rept Re Reactor Pressure Vessel Stabilizer Plate Incorrect Installation.Initially Reported on 760513.New Shim Plates Fabricated & Installed.Final Rept Will Follow Installation Completion & Receipt of GE Info

ML20085E777
Person / Time
Site:	Browns Ferry, 05000000
Issue date:	06/14/1976
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20085E768	List: ML20085E765 ML20085E777
References
NUDOCS 8308160579
Download: ML20085E777 (2)

Text

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JUM l' r!.3 Mr. hornan C. !!oseley, Director Office of Inspection end Enforcenent U.S. Uucicar Regulatory Conaission Region II - Suite 818 230 Peachtree Street, IM.

Atlanta, Georgia 30303

Dear IIr. lioscley:

BROWilS FERRY NUCIIAR PLA11T UNIT 3 - PIPORTABLE DEFICIENCY -

RPV STABILIZER PLATES DISTALLED DICORREC11Y Initial report of the subject reportabic deficiency was c:ade to G. R.12ingler, IHtC-IE, Region II, on May 13, 1976. In compliance with paragraph 50.55(e) of 10 CFR Part 50, we are enclosing an interiza report of the deficiency. A final report will be prepared once all of the new shins have been installed and pertinent backup information is received from General Electric.

' Very truly yours, J. E. Gilleland Assistant Manager of Power Enclosure CC (Enclosure):

Dr. E. Volgenau, Director' Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 P

8308160579 760005 PDR ADOCK 05000296 S PDR l

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4 An Equal Opportunity Employer

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ENCLOSUllE

. . BROWNS FERRY NUCLEAR PLANT UNIT 3 RPV STABILIZER PIA'IES INSTALLED INCORRECTLY

,, , DDR 232 - INTERIM REPORT The General Electric Company recently released s fleid disposition instruction (FDI) requesting that an inspecticn be perfomed on the

• reactor pressure vessel (RPV) seismic stabilizers at Browns Ferry lI Nuclear Plant. The purpose of the inspection was to detemine if the

., stabilizers were installed with sufficient clearances to permit rela-tive deflections between the reactor vessel and shield wall without binding and inducing cyclic stresses in the stabilizers.

i-In performing this inspection it was discoveied that part of the

!, stabilizer assembly had been incorrectly installed. Bearing plates

! at each end of the stabilizer assembly had been installed 90 degrees l' from the intended orientation. These plates make contact during a seismic event with bumper brackets mounted on top of the biological shield wall. 'Ihe incorrect orientation reduces the amount of contact

' area between the bearing plate and bumper bracket. This could lead

, ., to damage of the stabilizer assembly during a seismic event. .

After being notified of the deficiency, GE recommended one of two fixes:

! , (2j replace the shim plate on the bumper iscucket wiva a (1} new de different dimensions. Since the stabilizers are fully assembled and 7

are located in an area with limited access, rotation of the bearing plates would have been very difficult. Instead, new shim plates have been.

fabricated and are being installed.

A final report will be prepared once all of the new shims have been

-installed and pertinent backup information is received from GE.

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