ML20168A589
| ML20168A589 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1972-086-00 | |
| Download: ML20168A589 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number:
71694 Date:
May 26, 1972
Title:
Loss of Offsite Power at Palisades The failure sequence was:
- 1. With the plant in a hot standby condition, the left channel safety injection system test button was pushed to initiate a quarterly test.
- 2. This resulted in a loss of offsite power due to the spurious operation of a differential relay on the 1-2 startup transformer.
The actuation of the relay was due to unbalanced sensing 6urrents from a current transformer -
a result of the incompatibility of the installed current transformer with the 345 KV -
2.4 Ky step-down situation.
Corrective action:
The differential relays were removed from startup transformers 1-1 and 1-2.
High-side overcurrent and instantaneous overcurrent relays were installed.
Design purpose of failed system or component:
The differential relays provided overcurrent protection for the startup transformer.
Unavailability of system per WASH 1400:
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 HR-1.
Plant in Left Channel Loss of Offsite Diesel Gener-Diesel Generator Hot Standby Safety Injec-Power Due to ator Start Manually Syn-tion System Spurious Opera-chronized to Test Button tion of a Dif-Safeguard Buses Pushed to ferential Relay IC and ID (Due to Initiate on the 1-2 Test Button Quarterly Startup Trans-Depression)
Test former Potential Severe Core Damage No Yes Yes No NSIC 71694 -
Actual Occurrence for Loss of Offsite Power at Palisades
Loss of Turbine Emer-Auxiliary PORV PORV or High Long Offaite 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 Sequence No.
_______________________________No No No Yes Yes No No Yes 2
3 4
5 6
7 8
9 10 11 12 13 Yes No Yes
-V..
NSIC 71694 -
Sequence of Interest for Loss of Offsite Power at Palisades
- Not included in operating procedures
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
71694 DATE OF LER:
May 26, 1972 DATE OF EVENT:
may 17, 1972 SYSTEM INVOLVED:
Offsite power COMPONENT INVOLVED:
Startup transformer CAUSE:
Improperly chosen differential relay SEQUENCE OF INTEREST:
Loss of offsite power ACTUAL OCCURRENCE:
Loss of off site power during testing REACTOR NAME:
Palisades DOCKET NUMBER-255 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
805 MWe REACTOR AGE:
1.0 yr VENDOR: CE ARCHITECT-ENGINEERS: Bechtel OPERATORS:
Consumers Power Corp.
LOCATION: 5 miles south of South Haven, Michigan DURATION:
N/A PLANT OPERATING CONDITION: Hot standby SAFETY FEATURE TYPE OF FAILURE:
inadequate performance; (b) failed to start; (c)made inoperable; (d)
DISCOVERY METHOD:
During testing COMMENT:
The incompatible current transformer had been installed prior to criticality