ML20084A438

AO 3-2-13:on 731011,reactor Tripped Off Line Due to Loss of Generator Field Relay Action.Caused by Gaseous & Particulate Radioactivity in Auxiliary Bldg.Investigation Concluded That No Release to Atmosphere Occurred

ML20084A438
Person / Time
Site:	Indian Point
Issue date:	10/26/1973
From:	Cobean W CONSOLIDATED EDISON CO. OF NEW YORK, INC.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084A413	List: ML20084A411 ML20084A438
References
AO-3-2-13, NUDOCS 8304050188
Download: ML20084A438 (2)

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_ October 26, 1973 <h/

Re: Indian Point Unit No. 2 AEC Docket No. 50-247 Facility Operating License DPR-26 A.O. 3-2-13 Mr. John F. O' Leary Directorate of Licensing Office of Regulation U.S. Atomic Energy Commission Washington, D. C. 20545

Dear Mr. O' Leary:

The following report is provided pursuant to the requirements of Section 6.12.2(a) of the Technical Specifications for Faci-lity Operating License DPR-26.

On October 11, 1973, approximately one hour after a reactor shutdown from 50% of rated power, portable instrumentation in the Primary Auxiliary Tuilding indicated that an unplanned re- .

lease of gaseous and particulate radioactivity had been made within the building. The release was limited to the P.A.B.

and was removed from there via the normal plant vent system over a period of approximately one hour.

Immediately upon receipt of the alarm from the portable mrnitcr,

' investigative charcoal and millipore samples of'the plant vent ..-

effluent were taken and analyzed. In addition, a sample of the

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Na portable monitor filter paper was also analyzed for particulate M activity.

30 no An investigation was undertaken to determine the cause of the in-h o dicated release. Plant components and piping which handle waste

@g or radioactive gases were examined as possible sources. No faults

-u in equipment or operating procedures were found during the investi-80 gation which could directly account for the release. However, the

@< PAB ventilation system had been automatically shut down in connec-I oc tion with a safeguards signal which followed the reactor shutdown.

OSa: On the basis of this, and the fact that no equipment malfunction or improper procedure was uncovered, we have concluded that no unplanned release frcm the site did occur, and that the presence of airborne activity in the PAB resulted only from the building vent-ilation system being in ,a shutdown condition during a period of 2

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_ _ _ _ _ g Mr. John F. O' Leary October 26, 1973 Re: Indian Point Unit No.2 AEC Docket No.40-247 Facility Operating License DPR-26 A.O. 3-2-13 time in which liquid waste was being processed. Under normal circumstances, radioactive gases liberated from the liquid waste are directed to the plant vent via the PAB ventilation system.

In this case, since the ventilation system was secured, such gases accumulated within the building and this, in turn caused annuncia-tion of the aforementioned alarms.

Based on airborne activity levels recorded by two monitors located within the PAB, the amount of activity which accumu-lated in the building during the period of time the ventila-tion system was secured is estimated to be approximately one curie, the major portion of which was a mixture of xenon and krypton gases. The accumulation of I-131 and particulates with a half-life greater than 8 days is estimated to have been 35p ci and 7Aci, respectively. The maximum concentration of g airborne activity measured within the building, 3.25 x 10 5 pei/cc, is well below the applicable limit specified in 10 CFR 20, and the rate at which the gas was released from the

, site following restoration of the ventilation system was less ,

than 10% of the Technical Specification limit.

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Warren R. Cobean, Jr.

Manager - Nuclear Power Generation Department l cc: Mr. James P. O'Reilley Regulatory Operations, U.S.A.E.C.

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