ML20168A591
| ML20168A591 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1977-047-00 | |
| Download: ML20168A591 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
130119 Date: September 24, 1977
Title:
A Complete Loss of Offsite Power Occurs at Palisades The failure sequence was:
- 1. With the reactor at 100% power during an electrical storm, "R" bus de-energized and caused a complete loss of offsite of main condenser cooling.
- 2. The turbine tripped on high condenser vacuum, and effected generator trips.
- 3. Both diesel generators started and supplied electric-power loads.
the switchyard power and loss reactor and to safety-related Corrective action; none Design purpose of failed system or component:
Off-site power provides the preferred source of electric power to plant equipment when the unit generator is not in operation.
The condenser circulating water pumps are normally powered from the of fsite power source.
Unavailability of system per WASH 1400?:
loss of offsite power:
2 x 10-5 /hr Unavailability of component per WASH 1400:
Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour 11R'1.
Reactor at Switchyard bus Turbine trip Both diesel-One of two auxil-100% power "R" de-energized, on high back generators iary pumps pro-resulting in loss
- pressure, start and vide AFW to steam of offsite power reactor and assume safety-generators for and loss of con-unit genera-related loads reactor cooling denser cooling tor trip (LER does not specify which pump was used)
Potential Severe Core Damage No Yes No
- Yes No NSIC 130119 -
Actual occurrence fdr a Complete Loss of Offsite Power at Paligades
Loss of Turbine Emer-Auxiliary PORV PORV or High Long Offsite Generator gency Feedwater and Demanded PORV Isola-Pressure Term Power Runs Back Power Secondary tion Valve Injection Core and Assumes Heat Removal Closure Cooling House Loads Potential Severe Core Damage No Sequence No.
2 3
4 5
6 No No
'Yes Yes No No 7
Yes 8
9 Yes No I
Yes 10 11 12 13 X es NSIC 130119 -
Sequence of Interest for a Complete Loss of Offsite Power at Palisades
- Not included in mitigation procedures.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMB3ER:
130119 DATE OF LER:
October 18, 1977 DATE OF EVENT:
September 24, 1977 SYSTEMe I!N'VOLVED:
offsite power CO:ION'ENT INVOLVED:
switchyard "R" bus CAUSE:
bus trip from unknown causes SEQUENCE OF INTEREST:
loss of off site power ACTUAL OCCURRENCE:
reactor trip due t REACTOR NANE:
Palisades DOCKZET NU-MBER:
50-255 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
805 MWe REACTOR AGE:
6.5 yr VENDOR:
Combusfton Engineering ARCHITECT-ENGINLEERS:
Bechtel OPERATORS:
Consumers Power Co.
LOCATION: 5 miles south of South Haven, Mich.
o loss of offsite power DURATION:
N/A PLANT OPERATING CONDITION:
100%4 power SAFETY FEATURE TYPE OF FAILURE:
(a) inadequate performance; (b) failed to start;
. 0made inoperable; (d)
DISCOVERY MIET1EOD:
during operation COMDIENT:
-