ML19263C503

LER 79-010/01T-0 on 790202:section of Blowout Panel Blown Out,Breaching Secondary Containment.Cause Under Investigation

ML19263C503
Person / Time
Site:	Dresden
Issue date:	02/16/1979
From:	Chan J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17173A627	List: ML17173A626 ML19263C503
References
LER-79-010-01T, LER-79-10-1T, NUDOCS 7902260361
Download: ML19263C503 (2)

Text

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EVENT DESCRIPTION AND PROBABLE CONSEQUENCES O'o l o l 2 l l While U2 was in normal operation and U3 was in cold shutdown, a section of blowout l g 3 g panel at west side of refueling floor was blown out, breaching the recondary contain g g , g ment. U2 was subsequently shut down. The airborne radioactivity level was low on the; ,

r fueling fl r, therefore a low level release that may have occurred prior to re- y o s l 0 6 l l g , g significant. A simllar event was reported on 11/30/74 (U3 n.o.f/ 74-35) .  ;

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36 l0 01 4 31 I l43Y l@ lN[g lA[g lGl0j8l0lg 40 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h 1 O l Panel blown out after all exh. fans tripped while 4 supply fans stayed on pressurizing l li j i l l bldg. SBGT immediately was started and opening was covered with canvas to prevent re-I

, 7 l lease. It was later covered with steel sheathing. Exact cause and corrective action l gij3y[ are being investigated and will be reported later. l 1 4 l l 1

7 8 9 80 ST S  % POWER OTHER STATUS ISCOV RY DISCOVERY DESCRIPTION 1 5 l E l@ l0 l8 l7 l@l U3 Shutdown l l A l@l Observation l ACTIVITY CO TENT RELE ASED OF RELE ASE AMOUNT OF ACTIVITY LOCATION CF RELEASE 6 NA l' NA 7

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ATTACllMENT TO LICENSEE EVENT REPORT 79-10/01T-0 r.0M:10NWEALTil EDISON COMPN!Y (CUE)

DRECDEN UNIT -2 (ILDRS-2)

DOCKET # 050-237 While Unit 2 was in normal operation and Unit 3 was in cold shu rdown, a section of a blowout panel at the west side of the refueling floor was blown out, breaching the secondary containment. Unit 2 was sub-sequently shut down. The airborne radioactivity level was low on the refueling floor, therefore a low level release that may have occurred prior to restoring the building to a negative pressure with respect to the atnosphere was insignificant. A similar event was reported on 11/30/74 (Unit 3 R.O. #74-35). The panel had blown out after all exhaust fans tripped while four supply fans continued running thereby pressurizing the reactor building. The Standby Gas Treatment System was immediately started and the opening was covered with canvas to prevent any possible releare. The opening was later covered with steel sheathing.

Exact cause and corrective action are being investigated and will be reported later. .

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