ML20168A462

Final ASP Analysis - Dresden 3 (LER 249-77-054)

ML20168A462
Person / Time
Site:	Dresden
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1977-054-00
Download: ML20168A462 (4)

Text

November 29, 1977 Diesel Generator Trips Durimg Testimg at Dresden 3 lure sequence was:

veillance testing of diesel generator #12/3 was being performed when ripped after 10 minute of operation. An investigation revealed its cooling water pump had tripped and was inoperable. A mixture il and water had flooded the stator winding enclosure. The stator associated bearings were ruined. The mixture leaked in through the uit connected to the pump. No explanation was given for this.

operability test of diesel generators 2 and 3 was immediately performed.

el generator 3 started but tripped 30 minutes after loading. A acitor in the speed sensing circuit had shorted out.

orderly shutdown of unit 3 was initiated.

ive action:

damaged cooling water pump was replaced.

shorted capacitor was replaced.

purpose of failed system or component:

y power provides a.c. power when off site sources are unavailable.

ability of system per WASH 1400: *Emergency power: 10-2 /D ability of component per WASH 1400: Diesel En~ine failure to run:

3 x10 /hr Unavailabilities are in units of per demand D-1. Failure rates are In 1

f per hour HR- .

No, offsite power available h

j No No 55 - Actual Occurrence of a Diesel Generator Trips During Testing of Dresden 3

No 1 Yes 2 No 3 Yes 4 Yes 5 No 6 Yes 7 Yes 8 No 9 Yes 10 No 11 Yes 12 Yes 13 Yes 14 Yes 15 5 - Sequence of Interest of a Diesel Generator Trips During Testing at Dresden 3

ION NUMB3ER: 132155

December 13, 1977 NT: November 29, 1977 LVED: Emergency Power NVOLVED: Diesel Generators anical and electrical failures INTEREST: Loss of offsite power RRENCE: Diesel Generator Trips During Testing at Dresden 3 E: Dresden 3 ER: 50-249 E: BWR TRICAL RATING: 794 MWe

6.8 yr neral Electric NGINEERS: Sargent & Lundy Commonwealth Edison Nine miles E of Morris, Ill.

360(a) hours TING CONDITION: 75% power URE TYPE OF FAILURE: (linadequate performance; (b) failed to start; (0 made inoperable; (d)____________

ETHOD: testing