ML20080M649

Responds to NRC Re Violations Noted in IE Insp Rept 50-289/83-30.Corrective Actions:Loop Seals Reestablished in Leaking Floor Drains & Drain Line at Bottom of Elevator Shaft Will Be Permanently Capped

ML20080M649
Person / Time
Site:	Crane
Issue date:	12/22/1983
From:	Hukill H GENERAL PUBLIC UTILITIES CORP.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20080M648	List: ML20080M649
References
5211-83-360, NUDOCS 8402210219
Download: ML20080M649 (6)

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GPU Nuclear Corporation

~ NggIgf Post Office Box 480 Route 441 South Middletown, Pennsylvania 17057-0191 717 94 67621 TELEX 84 2386 Writer's Direct Dial Number:

December 22, 1983 5211-83-360 Mr. Richard W. Starostecki, Director Division of Project and Resident Programs U. S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406

Dear Sir:

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 Inspection Report 83-30 The subject NRC Inspection Report (Section 6) reviewed the TMI-1/TMI-2 krypton release incident of August 29, 1983, and the licenseee investigation and test to identify the release path.

The attached evaluation provides a detailed identification of verified and potential leak paths, as well as corrective action taken. This evaluation differa from that presented in Inspection Report 83-30.

We believe the attached evaluation to be more accurate of the two reports.

S cerely,

-F 11

. Hukill Director, TMI-l llDil: RAS:vj f Attachment cc:

R. Conte 8402210219 840213 PDR ADOCK 05000289 O

PDR GPU Nuclear Corporation is a subsidiary of the General Public UtilRies Corporation

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q-ATTACIC4ENT I On October 20,'1983, an investigation-and test was conducted to determine the actual flowpath of the released ' krypton ' gas, the nature of any defi-ciencies in the environmental barrier, and recossendations for corrective action.

The sample and ventilatien systerrconditions of August 29, 1983 were duplicated for the test.

A t' racer'gisl(R-12) was introduced at the same point.as the krypton gas, and electronic leak detectors were used to identify the flowpath of the R-12. is a sketch of the test set-up.

The-R-12 injection was initiated at 175E hrs.

The first detection of R-12 vapor occurred approximately 18 minutes later at the fiq$r drain and clean out plug.under the Intermediate Cloced' Cooling Surge Tank (IC-T-1) on the 348' elevation in the Spent Fuel Pool Area.

E-12 vapor was also detected at the floor drain just inside the entrance door tc this area (both in the Unit.1/2 common air' space). The next location dhere a flowpath was sus-pected was.the entrance door to the Spent Fuel Pool Area and the elevator doors leading to this doorway (348' el;).

R-12 vapor was detected at this locatior. at 1830 hrs.

The personnel performing this test rode the elevatore down to the 281'- elevation, where R-12 vapor was heavily detected at '.842 hrs.

It-is suspected that a drain.line, that terminates _ after it penetrates the elevator shaf t just above the elevator sump at (*276'cel.), as well as

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the floor drain -in' the elevator equipmentiro~ m is the cause of this leak.

o Based on the. test results, Plant Engineering concluded that when the krypton gas was injected into the Nuclear Sampling Room it travelled the path of least resistance into the drain system. The drain lines throughout -

the Auxiliary Building provided a' path'up to the Spcat Fuel Pool Area at the

-floor drains directly below the Intermediate Closed Cooling-Surge Tank (IC-T-1) and just inside the d'oorway.to this crea. Due to the lack of a loop seal in these floor drains, a flowpath was created for the krypton. gas.

In, addition,-

the drain line at.the bottom of the el'evator shgft provided an additional flowpath for the krypton gas.

The airflow is. drawn up the elevator-shaft, where it can leak'out around the elevator door seals and be drawn into the Spent Fuel Pool Area through the entrance door. These,three (3) flowpaths

. allowed the krypton gas to disperse into the common air space (348' el. is common to both Unit 1 and 2) and be ~ezhausted-by both units'. air handling systemswhich caused the alarms in both ' units.

It should be noted that-it took ~20 minutes from the time of injection for the krypton gas co produce a Fuel Handling Building radiaticu monitor alarm in the Control Room. This is consistent with the approximate 18 minute time frame.to detect the R-12 vapor at the 348' elevation of the Fuel Handling ~

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-All'of the verified leak paths appear'to be due to the lack of drain system 11oop seals and door seals.'

Job tickets 'have been -initiated.to correct verified l leek paths ~(see items 1, 2, 3 and 4).

Loop seals were promptly re-established in the-leaking floor drains and all appropriate floor' drain. loop seals were tidentifiedf.for inclusion in surveillance and maintenance procedures. Doors to the Spent' Fuel. Pool area (348' eli) and shipping and receiving area (305' el.)

of the Fuel.liandling Building have been made air tight. The drain line at the

, bottom of the.. elevator shaft (276' el.) will be ' permanently capped.

Actions

have also been completed to minimize any potential (See items 5, 6, & 7 attached)

leak paths between the Auxiliary and Tuel llandling Bulldings.

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The above test and corrective actions have elminated both verified and bc

. potential pathways for gross air exchange between units.

It is not believed

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'that further testing.is necessary.

Also, the design of the environmental iP'

' barrier.'and separation of ventilat.icn systems has been reviewed, and f'

- following.complet' ion of the corrective actions no further changes are deemed q

~necessary.

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,f" ATT CHMEiT 2 - CORRECTIVE ACTION LIST

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Thh following-is a list of company identified items and corrective actions.

r Item-f Auxi.11ary and Fuel Handling Building Drain System g

E The' R-12 test results clearly establish drain system problems. Many i of the floor drain loop seals are not maintained and some are not

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_ included in the Operation Surveillance Procedure (OPS-S59) or in Utility PM U-17 to clean all Zurn check valves.

s Procedure changes are being generated'!dentifying all the drain

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valves-for inclusion in OPS-S59 and PM U-17 checklists.

Item 2e Entrance door.to Spent Fuel-Pool Area (348' elevation).

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The door should be air' tight.

Installneddcorlockanddoor 1

_ knob.

Install new rubber door seal at clie bottom of door. The

- door should be turned around to allov the door to seal ~ agains the: door frame.

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JT #CC435 was initiated to correcUthis problem.

Door knob

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penetration is sealed. Doorknob is on order. The door was

-rehung and new seals installed.

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2. Personnel door for entrance to Shipping and Receiving Area T'

'(305' elevation) of Fuel Handling Building.

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The door should be air tight.

Fill the two (2) inch hole in door

.by installing a cover on both sides of door.

Install new door knob m.

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e and latch.

Install new rubber door seals at the bottom of door and t' 9 (

around door frame.

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JT'#CC383 initiated to correct this problem is complete.

T Item 4 Drain line at bottom of elevster shaft.

Fuel Handling Building

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(276' elevat'fon).

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,7 Repairdrainline,th$t.penetratesintobttomofelevatorshaft.

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Drain. lite should be capped.

If possible, braze cap on to drain

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line to prevent locsening of cap from vibrations.

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q JT #CC384 has been initiated to correct this problem.

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' Item 5

-Opening under Intermediate Cooling Surge Tank, 348' elevation'in Spent Fuel Pool ~ Area.

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Opening for penetration to Surge Tank should be sealed with fire i1' barrier penetration sealant. This opening provides a potential

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.a.flowpath from the 329' elevation.to the Spent Fuel Pool Area 4

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,I JT fCC3'85 initiated to correct this problem is complete.

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Item 6 Decay Heat Closed Surge - Tank Toom, 329' elevation of Fuel Handling Building.

There are several open penetrations in the wall of this room leading into the Fuel Handling Building ventilation chase. The chase is open down to'the 281' elevation of the Auxiliary Building. Fill openingr with-fire barrier penetration sealant.

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JT #CC386 irlitiated to correct this problem is complete.

' Item 7 Environmental Barrier Roof Decking, 351' elevation of the Spent

' Fuel Pool Area. Gaps in the sheet metal seam must be filled.-

Use RTV sealant.

- JT #CC382 initiated to correct this problem is completc.,

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