ML18283B380
| ML18283B380 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/14/1976 |
| From: | Gilleland J Tennessee Valley Authority |
| To: | Moseley N NRC/IE, NRC/RGN-II |
| References | |
| Download: ML18283B380 (3) | |
Text
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830 Power Building TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSEE 37401 June 14, 1976 Mr. Norman C. Moseley, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II Suite 818 230 Peachtree
- Street, NM, Atlanta, Georgia 30303
Dear Mr. Moseley:
BROMNS FERRY NUCLEAR PLANT UNIT 3 REPORTABLE DEFICIENCY-RPV STABILIZER PLATES INSTALLED INCORRECTLY Initial report of the subject reportable deficiency was made to G. R. Klingler, NRC-IE, Region II, on May 13, 1976.
In compliance with paragraph 50.55(e) of 10 CFR Part 50, we are enclosing an interim report of the deficiency.
A final report willbe prepared once all of the new shims have been installed and pertinent backup information is received from General Electric.
Very truly yo s,
Q~WJ
. Gilleland Assistant Manager of Power Enclosure CC {Enclosure):
Dr. E. Volgenau, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Mashington, DC 20555 An Equal Opportunity Employer
ENCLOSURE
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3RCM53 FERRY NUCLEAR PLANT UNIT 3
.REV STABILI2ZR PLATES INSTAIZZD INCORRECTLY
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DDR 232 - INTERIM REPORT The General Electric Company recently released, a field dispositi.on instruction (FDI) requesting that an inspecticn be performed on th reactor pressure vessel (RPV) seismic stabilizers at Browns Ferry Nuclear Plant.
The purpose of the inspection was to determine if'he stabi.lizers were installed with sufficient clearances to permit rela-tive deflections between the reactor vessel and shi.eld, wall withou.
binding and, inducing cyclic stresses in the stabilizers.
In performing this inspection i.
vas discovered. that part of the sta'oi.lizer assembly had. been incorrectly installed.
Bearing plates at each'end of the stabilizer assembly had. been installed. 90 degrees fram the intended. orientation.
These plates make contact during a
.sei.smic event with bumper brackets mounted. on top of the biological shi.eld. wall.
The incorrect orientati.on reduces the amount of contact
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area between the bearing plate and. bumper bracket.
This could lead.
...' to damage of the stabilizer assembly during a seismic event.
After bei.ng notifi.ed. of the deficiency, GE recommended one of two fixes:
(1) rotate the bearing plate 90 degrees to the correct orientation, or (2) reply ~ the shm plate on the bumper br':kit, wirh a new design os".
different dimensions.
Since the stabilizers are fully assembled.
- and,
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are located, in an area with limited. access, rotation of the bearing plates would have been very difficult.
Instead.,
new shim plates have bee"
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fabri.cated, and are being insta11ed..
A fina1 report will be prepared.
once a11 of the new shims have been "installed. and. pertinent backup information is received. from GE.