PNO-I-86-101, on 861230,leak from Blank Flange on Addition Line Connected to Vol Control Tank Discovered.Caused by Personnel Error.Release Well Below Tech Spec Limits & Radiation Monitor Readings Subsequently Decreased to Normal

PNO-I-86-101:on 861230,leak from Blank Flange on Addition Line Connected to Vol Control Tank Discovered.Caused by Personnel Error.Release Well Below Tech Spec Limits & Radiation Monitor Readings Subsequently Decreased to Normal

ML20207G500
Person / Time
Site:	Maine Yankee
Issue date:	12/30/1986
From:	Holden C, Lester Tripp NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-86-101, NUDOCS 8701070319
Download: ML20207G500 (1)

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s 50309861230 Date: Decembtr 30, 1986 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-I-86-101

-This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date.

Facility: Licensee Emergency Classification:

Maine Yankee Atomic Power Company Notification of Unusual Event Maine Yankee Atomic Power Station Alert Site Area Emergency Docket No. 50-309 General Emergency

__X_ Not Applicable

Subject:

UNPLANNED RELEASE At about 3:30 a.m., December 30, 1986, a plant ventilation radiation alarm was received fcr the primary auxiliary building (PAB). Immediate investigation revealed a leak from a blank flange on a 3/4-inch nitrogen addition line connected to the volume control tank (VCT). The release was terminated at 4:35 a.m.

An initial estimated release of 420 curies, primarily noble gas, occurred which r: presents approximately 0.01 percent of 10 CFR 20 limits and is well below Technical Specification limits.

A 3/4-inch nitrogen addition valve upstream of the blank flange was found to be not fully shut. Since operators had been working in the immediate vicinity adding hydrogen to the VCT, it is suspected that an operator may have bumped or mispositioned the nitrogen addition valve causing the release. Radiation monitor readings had decreased to normal by 7:30 a.m.

The State of Maine has been notified. While no press release.is planned, the licensee has informed the public through a taped telephone information message.

CONTACT: L.E. Tripp, RI C.N. Holden, SRI 215-337-5227 207-882-7519 DISTRIBUTION:

H. St. MNBB Phillips E/W Willste Mail: ADM:DMB Chairman Zech EDO NRR IE NMSS DOT:Trans only Comm. Bernthal PA OIA RES Comm. Roberts ELD AE00 NRC Ops Crt Comm. Asselstine Comm. Carr ACRS Air Rights INP0----

SECY SP NSAC----

CA PDR Regional Offices TMI Resident Section RI Resident Office Licensee:

(Reactor Licensees)

Region I Form 83 (Rev. July 1986) (J'

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'a o I 8701070319 861230 lt( ,

PDR ILE PNO-I-86-101 PDR - )]

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