ML19305D810

LER 80-019/01T-0:on 800326,found Possibility of Not Maintaining Control Room Habitability Due to Leakage of Unfiltered Air.Possibly Caused by Isolation Dampers. Corrective Mods Planned

ML19305D810
Person / Time
Site:	Sequoyah
Issue date:	04/08/1980
From:	Robinson F TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19305D804	List: ML19305D803 ML19305D810
References
LER-80-019-01T-01, LER-80-19-1T-1, NUDOCS 8004150547
Download: ML19305D810 (2)

Text

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1. -  : i I tnit 1 in Mode 6 with all fuel leaded. There is 'a possibility of not 1

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m t caintaining -a'lidit'ab'le con'tr'ol room due to leakana of unfiltered out- t

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i, . I ; side air into the main control recs. (TS 3.7.7.1) There is no danger to 1 i.,,i the health and safety of the public. Previous occurrence - None. ,

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Tennbasee Valley Authority Sequoyah Nuclear Plant LER SUPPLEMENTAL INFORMATION SQRO-50-327/ 8019 Technical Specification Involved 3.7.7.1 Reported Under Technical Specification: 6.9.1.12.1 Date of occurrence: 3/26/80 Time of Occurrence: 1620 EST Unit 1 Identification and Description of Occurrence:

There is a possibility of not maintaining a habitable control room due to leakage of unfiltered outside air into the main control room (EL. 732.0').

Conditions Prior to Occurrence:

Unit 1 in Mode 6 with all fuel loaded.

Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment.

P N/A Apparent Cause of Occurrence The leakage could come from (1) isolation dampers which shut off normal supply of pressurizing air to tbc main control room (El. 732.0') and (2) openings for the motor drive belts for the smoke removal fan. The smoke removal fan is connected to the battery room exhaust duct which passes through control room (El. 732.0').

Analysis of Occurrence:

There was no danger to the health and safety of the public.

Corrective Action:

The pressurizing supply duct will be disconnected from the return plenum for the air handling units. Two motor-operated dampers will be added to seal off the normal pressurizing supply air to the main control room elevation 732.0'. The existing smoke removal fan will be replaced with a direct drive fan that has the motor enclosed in the fan housing. The above changes will be made prior to initial criticality.

Failure Data:

N/A e

e 1