ML20168A462
| 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
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
132155 Date: November 29, 1977
Title:
Diesel Generator Trips Durimg Testimg at Dresden 3 The failure sequence was:
- 1. Surveillance testing of diesel generator #12/3 was being performed when it tripped after 10 minute of operation. An investigation revealed that its cooling water pump had tripped and was inoperable.
A mixture of oil and water had flooded the stator winding enclosure.
The stator and associated bearings were ruined.
The mixture leaked in through the conduit connected to the pump.
No explanation was given for this.
- 2. An operability test of diesel generators 2 and 3 was immediately performed.
Diesel generator 3 started but tripped 30 minutes after loading.
A capacitor in the speed sensing circuit had shorted out.
- 3. An orderly shutdown of unit 3 was initiated.
Corrective action:
- 1. The damaged cooling water pump was replaced.
- 2. The shorted capacitor was replaced.
Design purpose of failed system or component:
Emergency power provides a.c. power when off site sources are unavailable.
Unavailability of system per WASH 1400: *Emergency power:
10-2 /D Unavailability of component per WASH 1400: Diesel En~ine 3 x10 /hr failure to run:
- Unavailabilities are in units of per demand D-1.
Failure rates are In units of per hour HR-1.
Surveillance Testing Of Diesel 2/3 Tripped After Diesel Generator #13 Tripped Diesel Generator 2/3 10 Minutes of Operation Of f Line After 30 Minutes Was Underway Due To A Failed Cooling Due To A Shorted Capacitor Water Pump In Speed Sensor Potential Severe Core Damage h
j No, offsite power available No No NSIC 132155 -
Actual Occurrence of a Diesel Generator Trips During Testing of Dresden 3
Loss of Reactor Diesel Reactor Made Sub-RCIC/HPCI ADS/LPCI Long Powier Sca Loartad SBcSrica Rod Are Initiae CS Tes Cre Powier Sra Startad SBcSrica byd the Initiates CSoTer Manually Driven Inj Cooling Potential Severe Core Damage Sequence No.
No Yes No Yes Yes No Yes Yes No Yes No Yes Yes Yes Yes 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 NSIC 132155 -
Sequence of Interest of a Diesel Generator Trips During Testing at Dresden 3
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMB3ER: 132155 DATE OF LER: December 13, 1977 DATE OF EVENT:
November 29, 1977 SYSTEM INVOLVED:
Emergency Power COMPONENT INVOLVED: Diesel Generators CAUSE: mechanical and electrical failures SEQUENCE OF INTEREST: Loss of offsite power ACTUAL OCCURRENCE:
Diesel Generator Trips During Testing at Dresden 3 REACTOR NAME:
Dresden 3 DOCKET NUMBER:
50-249 REACTOR TYPE:
BWR DESIGN ELECTRICAL RATING:
794 MWe REACTOR AGE:
6.8 yr VENDOR:
General Electric ARCHITECT-ENGINEERS: Sargent & Lundy OPERATORS:
Commonwealth Edison LOCATION:
Nine miles E of Morris, Ill.
DURATION:
360(a) hours PLANlT OPERATING CONDITION:
75% power SAFETY FEATURE TYPE OF FAILURE:
(linadequate performance; (b) failed to start; (0 made inoperable; (d)____________
DISCOVERY METHOD:
testing COMMENT: