ML20168A590
| ML20168A590 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/16/2020 |
| From: | Christopher Hunter NRC/RES/DRA/PRB |
| To: | |
| Littlejohn J (301) 415-0428 | |
| References | |
| LER 1974-074-00 | |
| Download: ML20168A590 (4) | |
Text
PRECURSOR DESCRIPTION AND DATA NSIC Accession Number: 97578 Date:
November 15, 1974
Title:
Loss of Offsite Power During SIS Testing at Palisades The failure sequence was:
- 1. With the plant in a hot standby comdition, the right channel safety injec-tion test buttom was pushed to initiate a quarterly test.
- 2. Of fsite power was lost due to the inadvertent operation of the differential relay system.
- 3. The diesel generators started and powered safety-related loads.
Corrective action:
The three-phase differential relays were removed from service pending a review and potential redesign of the system.
Over-current protection devices remained installed to provide transformer protection.
Design purpose of failed system or component:
The differential relays provided overcurrent protection for the startup transformers.
Unavailability of system per WASH 1400: *Offsite power:
2 x lo05 /hr Unavailability of component per WASH 1400:
Unavailabilities are in units of per demand D-1.
Failure rates are in units of per hour HRR'.
Plant in Right Channel Safety Injection Loss of Offsite Power Diesel Generators Start Hot Standby System Test Button Pushed due to Inadvertent jand Provide Power to to Initiate Quarterly Test Operation of the Dif-Safety-Related Loads ferential Relay System Potential Severe Core Damage No Yes A
No NSIC 97578 -
Actual Occurrence for Loss of Offsite Power During SIS Testing at Palisades
Loss of Turbine Emer-Auxiliary PORV PORV or High Long Offsite Generator gency Feedwater and Demanded PORV 7'ola-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 w9bl~m No No Yes Yes No No Yes 2
3 4
5 6
7 8
9 10 11 12 13 r
No Yes NSIC 19-7578 Sequence of Interest for Loss of Of fsite Power During SIS Testing at Palisades Not included in mitigation sequence.
CATEGORIZATION OF ACCIDENT SEQUENCE PRECURSORS NSIC ACCESSION NUMBER:
97578 DATE OF LER:
November 15, 1974 DATE OF EVENT:
October 17, 1974 SYSTEM INVOLVED:
Offsite Power COMPONENT INVOLVED:
Differential Relays CAUSE:
improperly designed Differential Relay System SEQUENCE OF INTEREST:
Loss of offsite power ACTUAL OCCURRENCE:
Loss of offsite power during SIS testing REACTOR NAME:
Palisades DOCKET NUMBER:
50-255 REACTOR TYPE:
PWR DESIGN ELECTRICAL RATING:
805 MWe REACTOR ACE:
3.4 yr
'VENDOR:
Combustion Engineering ARCTHITECT-ENGINEERS:
Bechtel OPERATORS:
Consumers Power Company LOCATION:
5 mnies south-of -South Haven, Mich.
DURATION:
N/A PLANT OPERATING CONDITION:
hot standby SAFETY FEATURE TYPE OF FAILURE:
(alinadequate performance; (b) failed to start; 0c)Tade inoperable; (d)____________
DISCOVERY METHOD: testing COMMENT: This event is the second of its type at Palisades. After the first event (NSIC 71694, 5/17/72), the differential relays were removed pending a -design review. They were reinstalled in January 1974 after modification.