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
of Offsite Power During SIS Testing at Palisades equence was:
plant in a hot standby comdition, the right channel safety injec-buttom was pushed to initiate a quarterly test.
power was lost due to the inadvertent operation of the differential stem.
el generators started and powered safety-related loads.
tion:
ase differential relays were removed from service pending a review redesign of the system. Over-current protection devices remained provide transformer protection.
e of failed system or component:
tial relays provided overcurrent protection for the startup 5
y of system per WASH 1400: *Offsite power: 2 x lo0 /hr y of component per WASH 1400: -
1 bilities are in units of per demand D- . Failure rates are in hour HRR'.
due to Inadvertent jand Provide Power to Severe dby System Test Button Pushed Operation of the Dif- Safety-Related Loads Core to Initiate Quarterly Test ferential Relay System Damage No Yes A
No IC 97578 - Actual Occurrence for Loss of Offsite Power During SIS Testing at Palisades
Runs Back Power Secondary tion Valve Injection Core Core and Assumes Heat Removal Closure Cooling Damage House Loads No No 2 No 3 Yes 4 Yes 5 No 6 No 7 Yes 8 r 9 No 10 Yes 11 12 13 SIC 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 CESSION NUMBER: 97578 LER: November 15, 1974 EVENT: October 17, 1974 INVOLVED: Offsite Power NT INVOLVED: Differential Relays improperly designed Differential Relay System E OF INTEREST: Loss of offsite power OCCURRENCE: Loss of offsite power during SIS testing NAME: Palisades NUMBER: 50-255 TYPE: PWR ELECTRICAL RATING: 805 MWe ACE: 3.4 yr
- Combustion Engineering ECT-ENGINEERS: Bechtel RS: Consumers Power Company N: 5 mnies south-of -South Haven, Mich.
N: N/A PERATING CONDITION: hot standby FEATURE TYPE OF FAILURE: (alinadequate performance; (b) failed to start; 0c)Tade inoperable; (d)____________
RY METHOD: testing
- 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.