PNO-III-87-054, on 870409,unit Manually Shut Down & Scrammed Following Vacuum Problem in Main Condenser & Increasing Temp in Hotwell.Caused by Partially Dislodged Ceiling Embedment Plate Supporting Portion of Lpci.Plate Repaired

PNO-III-87-054:on 870409,unit Manually Shut Down & Scrammed Following Vacuum Problem in Main Condenser & Increasing Temp in Hotwell.Caused by Partially Dislodged Ceiling Embedment Plate Supporting Portion of Lpci.Plate Repaired

ML20206P712
Person / Time
Site:	Dresden
Issue date:	04/13/1987
From:	Ring M, Warnick R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-87-054, PNO-III-87-54, NUDOCS 8704210250
Download: ML20206P712 (1)

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-III-87-54 Date April 13, 1987 O This prelininary notification constitut's EARLY n': tic 7 cf events of POSSIBLE safety or public int: rest significance. The information is as initially received without verification or cvaluation, and is basically all that is known by the Region III staff on this date.

Facility: Commonwealth Edison Company Licensee Emergency Classification:

Dresden Unit 3 Notification of an Unusual Event Morris, IL 60450 Alert Site Area Emergency Docket No. 50-249 General Emergency X Not Applicable

Subject:

MANUAL SCRAM BECAUSE OF CONDENSER VACUUM PROBLEM At 11:35 (CDT) on April 9,1987, Unit 3 was manually shut down (scrammed) from approximately 20 percent power because of a vacuum problem in the main condenser and increasing temperature in the hotwell. The unit had been initially at 100 percent power when the loss of condenser vacuum problem began, and operators started to reduce power.

All systems functioned properly during the scram, although 22 control rod drives stopped at position 02 (one notch from being fully inserted). When the scram signal wa:: reset, the rods went to a fully inserted position. (This rod position situation is a characteristic occurrence at the Dresden units.)

While the reactor was shut down, the licensee performed repairs on a ceiling embedment plate, which supported a portion of the low pressure coolant injection (LP(,1) system. The plate had partially pulled out of the concrete, and the plant was in a 7-day Limiting Condition of Operation because the system was declared inoperable. The licensee was in the process of evaluating the original fabrication of similar embedments in both Dresden units and Quad Cities 1 and 2. Region III (Chicago) is monitoring the licensee's review. The results of this review, potentially affecting some 2,200 pipe supports, could affect the plant's continued op; ration and the startup schedule for Unit 2, which is in a refueling and modification outage.

The unit resumed operations at 3:20 p.m. on April 12, 1987, and is operating off line at 500 psi pressure while the licensee attempts to locate the source of the air leakage into the condenser.

The State of Illinois will be notified.

Region III was notified of this event at 4:45 a.m. on April 10, 1987. This information is current as of 10 a.m., April 13, 1987.

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CONTACT:# M. Ring R. Warnick F FTS 388-5602 FTS 388-5575 DISTRIBUTION:

H. St. EDO NRR E/W Willste Mail: ADM:DM8 Chairman Zech PA IE Comm. Roberts NMSS D0T:Trans only ELD OIA RES Comm. Asselstine Com. Bernthal AE0D NRC Ops Ctr MdB Com. Carr SP 84(f Regional Offices ACRS SECY CA INP0 8.*6 D NSAC M RIII Resident Officp PDR Licensea: f' O(o (Corp. Office - Reactor Lic. Only) 8704210230 PDH 18<E 870413 0

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Region III PNO-JII-87-054 PDR Rev. November 1986.IEJ'/