ML19318A590

Ro:On 800513,secondary Cooling Tower Fan Discovered to Have Disintegrated Causing Damage to Cooling Tower & Resulting in Loss of Secondary Cooling Capacity.Caused by Failure of Fan Transmission Mounting.Temporary Fan Assembly Installed

ML19318A590
Person / Time
Site:	05000128
Issue date:	05/23/1980
From:	Feltz D TEXAS A&M UNIV., COLLEGE STATION, TX
To:
References
NUDOCS 8006230420
Download: ML19318A590 (2)

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TEXAS A&M UNIVERSITY NUCLEAR SC:ENCE CENTER g,

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COLLEGE STATiCN. TEXAS 77843

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23 May 1980 Mr. G. L. Madsen Office of Inspection and Enforcement Region IV U.S. Nuclear Regulatory Constission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012 Ref: Docket No. 50-128 Subj ect: Damage to the NSC Cooling Tower Reported on May 13, 1980

Dear Mr. Madsen:

Enclosed is a final report of the damage to the NSC secondary loop cooling tower reported to your office on May 13, 1980. This report is submitted in compliance with Section 6.4 of the Technical Specifications, Facility License R-83 for the Nuclear Science Center, Texas A&M University.

Respectfully,

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Donald E. Feltz Associate Director DEF/ym Enclosure cc: 'R. R. Berg, Chairman Reactor Safety Board Texas A&M University 0

yb 8006280410 TEMAS ENGINEERING EXPERIMENT STATICN : RESEARCH AND oEVELCPMENT FOR MAMIND

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Final Report of Damage to the NSC Secondary Loop Cooling Tower and Loss of Pool Cooling Capacity l

Occurrence On May 13, 1980 it was discovered that the secondary cooling tower fan had disintegrated causing damage to the cooling tower and resulting in the loss of the secondary cooling capacity. There were no injuries and the scheduled reactor operations for the day were not interrupted. NSC management considered it appropriate to report this occurrence even though it does not render the reactor or its operation unsafe.

__aalysis The mounting for the fan transmission failed causing the fan blades to rip through the walls of the fan blade housing. The fan blades broke away from the transmission hub when they made contact with the wood structured fan housing. The fan, assembly and the fan housing were damaged beyond repair.

The fan assembly was recently inspected by a factory representative and found to be in need of repair. Repair parts were on order at the time of the incident but shipment was not scheduled until early June 1980.

Conclusions and Corrective Action The reactor was operated on a reduced schedule until May 21, 1980 when a temporary fan assembly was placed into service. The temporary fan installation provides approximately three fourths (3/4) the original cooling capacity which is adequate for the normal schedule of reactor operations.

The temporary fan assambly consists of 4 fan units mounted in a 2 x 2 array on a wood beam support structure which spans the circular opening at the top of the cooling tower. Each fan unit consists of a 54" x 54" steel frame housing with a 7 horse power. motor and direct drive fan blade assembly.

The original design replacement should be in service within two months.

It is planned to retain the temporary fan assembly for emergency use should the need arise again.

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