ML19210A230

Abnormal Occurrence 75-03:on 750626,noble Gas Released to Auxiliary Bldg.Probable Cause:Evaporator Malfunction While Filling Makeup Tank or Coolant Bleed Tank.No Tech Specs Exceeded

ML19210A230
Person / Time
Site:	Three Mile Island
Issue date:	06/27/1975
From:	Colitz J METROPOLITAN EDISON CO.
To:
Shared Package
ML19210A227	List: ML19210A226 ML19210A229 ML19210A230
References
NUDOCS 7910240942
Download: ML19210A230 (2)

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f.V3 ROUTINE TEPORT 475-03

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%5" A;72 METROPOUTAN EDlSOt; CCMPANY svassounvoreenenavuaucurrurossccaronarion TEt.EPHONE 717-944 4041 POSTOFFICE BOX 480 MIDDt.ETOWN. PENNSYLVANIA 17CS7 June 27, 1975 Y' h. \

Mr. J. P. O'Reilly

@  ;; P Directorate of Regulatory Operatians Region I 1 O (\)

E b'h p' W 'j G31 Park Avenue King of Prussia Pa. 19406 Operating 1.icense DPR-50 Docket 50-289 Subject- Unplanned release of radioactive material at THI thmugh the plant vent from the Auxiliary Bu(1 ding. .

Dear Mr. 0*Pell1y,

11rfs telegram is to confinn the conversation between Bert Davis (Region I -

tl2C), and J. G. lierbein (Manager, Generation Operations' " 1Nuc] ear) at 123G hours 27 June,1975.

On 25. June. starting at 0227. Inadvertent sporadic noble gas twieases occurred over a fourteen (14) hour period. Toe total time of the releases was sevan (7) hours and six (6) cinutes.

Due to the fact that the level of the activity released was so low..an ealqc.t er air.na condition did not occur.on the Radiation M2nitoring System. The releases were not detected until the routine shift check of the Radiation ibnitoring System Upon invest.igation it was detennined that Strip Chart Recorders was performed.Un atleases occurred fo11cwing makeup to the m tanks. It is postulated that the releases occurred from one of the evaporators which were, at the time of the release, shutdswo and va?ved into the redinactive gas vent header. The addition of water to the tanks caused a pressure scr;e which was subseqtently transmitted to tne shutriemn evaporators which, in ttarn, leded radioactive gas to the Auxiliary Building Yentilation Exhaust System. After iso-lation of the evaporators frn:n the vent header. no releases cccurred daring st nilu-operations.

Analysis of RM-A3 recsrder charts and local Auxiliary 1}ggiding samplev indicated the radieactive material released was prudemiaantly Xed .

The maxiram in taneous noble gas release rate that occurred during this period Ess 1.16 x 17gtag/sec.,

M which is below the Technical $cccification lietit of 3

L2 x 105 3 /ter. The maxicusa averace release rate during this period ssas C.72 x 10+2 W/sec. with a total release of 3.965 curies.

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MR. J. P. C'Pa111y 2.0 May 27, 1975 An investigation will be conducted to determine the exact location of the gas release point fmm the evaporators.

The necessary corrective action will be taken following the location of the gas release point.

Very truly yours, J. J. Colitz thtt il Superintendent JJC: Jam f

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