ML19208A813

LER 79-078/03L-0:on 790815,in Mode 1,excessive Noise & Vibration Detected Emanating from Auxiliary Bldg Ventilation Exhaust Fans AHF-14B & 14D.Caused by Loose Motor Mounts on Fan AHF-14B.Mounts Tightened

ML19208A813
Person / Time
Site:	Crystal River
Issue date:	09/05/1979
From:	Cooper J FLORIDA POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19208A810	List: ML19208A809 ML19208A813
References
LER-79-078-03L, LER-79-78-3L, NUDOCS 7909170544
Download: ML19208A813 (2)

Text

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, ,the plant or general public as a redundant set of fans AHF-14A and 14C were I o s iplaced into service. AHF-14B and 14D were secured and created ,, ovone -- I

, , ;trary to Technical Specification 3.7.8.1 dnd a 'even (7T dav action statement I

,,, ,was implemented. Full operability was restored following maintenance and test-l

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. Cooper . est (904) 795-64J6 (SEEATT!HEDSUPPLEMENTARYINFORMATIONSEEET) 7 90917o $_Y9- l

SUPPLEMENTARY INFORMATION Report No.: 50-302/79-078/03L-0 Facility: Crystal River Unit #3 Report Date: 5 September 1979 Occurrence Date: 15 August 1979 Identification of Occurrence:

One pair of Auxiliary Building exhaust ventilation fans inoperable contrary to Technical Specification 3.7.8.1.

Conditions Prior to Occurrence:

Mode 1 power operation. (100%)

Description of Occurrence:

At 1806, excessive noise and vibration was detected emanating from Auxiliary Building ventilation exhaust fans AHF-14B and 14D. Exhaust fans AHF-14A an'd 14C were placed into operation and AHF-14B and 14D were secured. The secur-ing of AHF-14B and 14D created an event contrary to Techni-cal Specification 3.7.8.1 and entry into a seven (7) day action statement was implemented. Investigation revealed that the fan motor mounts were loose on AHF-14B and some blade tip rub was evident on the shroud. No discrepancies were noted on AHF-14D. Full operability was restored, following maintenance and satisfactory functional testing at 0350, 17 August 1979.

Designation of Apparent Cause:

The cause of this event is attributed to loose fan motor mounts on Auxiliary Building ventilation exhaust fan AHF-14B.

Analysis of Occurrence:

There was no hazard to the plant or general public as redund-ant fans AHF-14A and 14C were operable.

Corrective Action:

The fan motor mounts on AHF-14B were tightened and the fan blade and blade tip rub areas on the shroud were checked for damage. All Auxiliary Building ventilation exhaust fan motor mounts were chac?ed for looseness with no additional finding resulting.

Failure Data:

First occurrence of this type reported, other occurrences reported by LER's 77-64, 76, 131, 151; 78-64, 65, 66, 70; and 79-10.

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