PNO-III-89-033A, on 890508 & 09,gaseous Release Occurred from Coolant Vol Control Sys Mixed Bed Demineralizer 1A Through Floor Drains to Auxiliary Bldg Vent Stack.Region III Monitoring Licensee Investigation

PNO-III-89-033A:on 890508 & 09,gaseous Release Occurred from Coolant Vol Control Sys Mixed Bed Demineralizer 1A Through Floor Drains to Auxiliary Bldg Vent Stack.Region III Monitoring Licensee Investigation

ML20247A871
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	05/11/1989
From:	Hinds J, Mckenna E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-89-033A, PNO-III-89-33A, NUDOCS 8905230300
Download: ML20247A871 (1)

PRELIMINARY _ NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-III-89-33A D:te May 11, 1989 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public intertst significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.

! Facility: Connonwealth Edison Co. Licensea Emergency Zion Unit 1 Classification:

Zion, IL 60099 X Unusual Event Alert Docket No. 50-295 Site Area Emergency General Emergency Not Applicable

Subject:

UNPLANNED GASE0US RELEASE ----(UPDATE)

At 5:15 p.m. (CDT), May 9, 1989, Unit 1 incurred an unplanned gaseous release from the Coolant Volume Control System's 1A mixed bed demineralized, through fi ar drains to the Auxiliary Building vent stack. The release rate was 10 percent of technical sp:cifications.

It was the second release from the 1A mixed bed demineralized in two days. At 9:45 a.m.

(CDT), May 8, operators opened vent and drain valves of the demineralized to begin pr:parations to change resins. Shortly afterward, operators received a high radiation alarm on the Auxiliary Building vent stack radiation monitor. The demineralized was subsequently isolated and the release terminated after operators concluded that the outlet valve to the 1A r: sin bed was leaking (see PN0-III-89-33).

The second unplanned release occurred as the licensee was valving in the IB mixed bed demineralized. The water from the let down line backed up through the leaking 1A demineralized outlet valve and then out an open 1A demineralized vent valve.

R:gion III (Chicago) is monitoring the licensee's investigation of these two incidents.

The t ate of Illinois will be notified.

R:gion III learned of the second release at 9 a.m. (CDT), May 10, 1989. This information is current as of 10:30 a.m. (CDT), May 11, 1989.

1 CONTACT: briq\

E. McKenna . Hinds FTS 388-5603 FTS 388-5575 )

DISTRIBUTION:

WHITE FLINT NORTH 1 MNBB REGIONS FAX TO:

Chairman Zech CA KEUU RI INP0//;tf Comm. Roberts OGC ARM RII NSACg7.Qf Comm. Carr 01 OIA RIV Licensee 4:55 Comm. Rogers EDO RV NRC Ops Ctr /:56-Comm. Curtiss NRR NL MAIL T0: PDR (8/634-3343) .3:00 SECY NMSS RES DCS (Orig.)

GPA/SLITP/PA ACRS DOT (Trans. Only)

ASLAP Rev. 03/01/89 52 00 890511 PNO-III-89-033 PNU e\

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