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.

.TENNESCEE VALLEY AUTHORITY*

.

6N 38A Lookout PlaceJanuary 16, 1990

I

U.S. Nuclear Regulatory ConunissionATTN Document Control Desk

-Washington, D.C. 20555

Gentlemen

TENNESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNIT 1 - DOCKET NO.50-327 - FACILITY OPERATING LICENSE DPR-77 - LICENSEE EVENT REPORT (LER)50-327/89034

The enclosed LER provides details of an event wherein an increased airborneactivity level in the auxiliary building resulted in suspension of the hourly

' fire watch patrol and subsequent noncompliance with TechnicalSpecification 3.7.12. This' event is being reported in accordance with10 CFR 50.73, paragraph a.2.i.

Very truly yours.

TENNESSEE VALLEY AUTHORITY

!. w-

R. Byn Vice President.

L Nuclear Power Production

Enclosurecc (Enclosure):

Regional AdministrationU.S. Nuclear Regulatory Commission

i

Office of Inspection and Enforcementi

! Region II| 101 Marietta Street Suite 2900' Atlanta, Georgia 30323

INPO Records CenterInstitute of Nuclear Power Operations1100 circle 75 Parkway Suite 1500Atlanta, Georgia 30339

NRC Resident InspectorSequoyah Nuclear Plant2600 Igou Ferry RoadSoddy Daisy Tennessee 37379

9001230218 900116PDR ADOCK 05000327 [ 'S PDC F

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An Equal Opportunity Employer "

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S2quoyah Nucicar Plant, Unit 1 0 |6 | 0 |0 | 0 | 312] 7 1 |0F|013"'''''' Increased airborne activity in the auxiliary building resulted in the suspension of firewatch patrols and subsequent noncompliance with Technical Specifications 3.7.12.

EVENT Daf t (S) Lim NUMeth ill REPORT DATE m OTHER S ACILITit$ INVOLVED ($1

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LICIN$tt CONT ACT FOR TMil Lth neiNAME TELEPHONE NUMBER

' " ' ' *Ceoffrey llipp, Compliance Licensing Engineer61115 81 41 31-17171616

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At 1533 Eastern standard time (EST) on December 15, 1989, with Unit 1 at 100 percentpower and Unit 2 at 80 percent power, the hourly fire watch patrol through the auxiliarybuilding could not be completed because of increased levels of airborne radioactivity.

.

At 1430 EST a leak was identified from a fitting on a Unit 1 volume control tank (VCT) i

Isvel transmitter. At 1500 EST entry into the auxiliary building was restricted, and at1525 EST, the auxiliary building was evacuated. As a result, the fire watch patrol wasnot allowed to enter the auxiliary building for the hourly rounds required by ActionStatement (a) of Limiting Condition for Operation 3.7.12. Personnel were allowed toroturn to the auxiliary building at 1800 EST when air samples showed airborne activityh:d returned to an acceptable level, and the hourly fire watch patrol was resumed. Theroot cause of this event was the VCT level transmitter leak, which was the source of the

lcirborne activity. The corrective action taken to eliminate the source of the airborne

| ectivity was to isolate the VCT level transmitter and tighten the leaking fitting. Awork request was written to replace the fitting.

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UCENSEE EVENT CEPORT (LER) ',Us'O.',%',f?8R mow'Fa"S's,%*N.7,*J.".'#! |i

TEXT CONTINUATION Pg.'To',';FM.",?niMij,"d''c'ME".' OETn'*

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Of MANAGEMENT AND DuDG4 T.W A&MINGTON. DC K403

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vuxt m . w. s.wnac e mmawnnDescription of Event

;

t

At 1533 Eastern standard time (EST) on December 15, 1989, with Unit 1 in Mode 1 at '

100 percent power, 2.235 pounds per square inch gauge (psig), 578 degrees Fahrenheit(F), and Unit 2 in Mode 1 at 80 percent power, 2,235 psig, 568 degrees F, the hourly.fire watch patrol through the auxiliary building (EIIS Code NF) could not be completed

;b3cause of increased-levels of airborne radioactivity. Higher than normal dose rates ,

w;re first detected at 1415 EST in the Unit 1 Elevation 690 penetration room. At :

1630 EST a leak was identified from a sample cap fitting on a Unit 1 volume control tank *

(VCT) level transmitter (1-LT-62-129A). The VCT is a holding and processing tank for !

tha chemical and volume control system (EIIS Code CB). The Unit 1 operator was notifiedcf the leak, and arrangements were made for instrument mechanics to isolate the leveltrcasmitter. At 1500 EST entry into the auxiliary building was restricted, and at

,

1525 EST the auxiliary building was evacuated. As a result, the fire watch patrol was '

not allowed to enter the auxiliary building for the hourly rounds as required byLimiting Condition for Operations (LCO) 3.7.12. The VCT level transmitter was isolated, ,

,

cnd the leaking fitting tightened. A work request has been written to replace thefitting. The appropriate radiological surveys were made, and air sampics were taken and |cn21yzed. Personnel were allowed to reenter the auxiliary building at 1800 EST, and the '

h:urly fire watch patrol was resumed.

! Cause of Eventi

Tha immediate cause of this event was the failure to complete the required hourly fire *

patrol because of an increase in the level of airborne radioactivity in the auxiliary;building. This condition represented an ALARA (as low as reasonably achievable) concern'

,

and access to the area had been restricted. "

Th3 root cause of this event was the VCT level transmitter fitting leak that was the '

source of the airborne activity. The threads on the fitting.had deteriorated or beendamaged causing the sample cap to leak.

Annlysis of Event

This event is being reported in accordance with 10 CFR 50.73, paragraph a.2.1, as anep; ration prohibited by technical specifications because the action requirements ofLCO 3.7.12 were not met.

,

Tho hourly fire watch patrol was being performed as required by Action Statement (a) ofLCO 3.7.12 because of nonfunctioning fire barriers and as required by commitments to ,

maintain hourly fire watches until certain Appendix R modifications are completed duringth3 Cycle 4 refueling outage for each unit. Although the auxiliary building was not .

visually inspected for fires during the interval from 1533 to 1800 EST, automatic firedstectors and fire suppression systems were in service and operable during this time.Th refore, there was no significant degradation in the overall level of fire protectionat the plant.

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UCENSEE EVENT REPORT ILER) W;"t?W,f*8'MM'!;j;"i',? *f!.'.',*o'.".l'@TEXT CONTINUATION *?74%'.';!*.'"f!"ci f,EN',ME'c'"'/12 '".' UETf!-

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Siquovah Nuclear Plant, Unit 1 0 |6 |0 |0 |013| 2| 7 8|9 0|3|4 010 0| 3 0F 0 |3,- -

Textuni . ww. .m w= ace amawnriCurrective Action

The immediate action taken was to restrict entry to and subsequently evacuate thecuxiliary building as a conservative protective action. The corrective action taken tooliminate the source of the airborne activity was to isolate the VCT level transmittercnd tighten the leaking fitting. A work request has been written to replace thefitting.

Personnel were allowed to return to the auxiliary building when air samplesshowed airborne activity had returned to an acceptable level.

Additional Information

There have been 36 previous reported occurrences of a failure to perform required firewatch patrolst however, only three of these occurrences were caused by personnel accessr:strictions resulting from high airborne activity levels. These three occurrences aredatalled in LER 50-327/88028, 88031, and Special Report 88-11. Because this airborneovent resulted from unexpected equipment degradation, corrective actions for previousevents could not be expected to have prevented this event.

Crmmitments

None.

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