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
May 26, 1972 Loss of Offsite Power at Palisades ilure sequence was:
th the plant in a hot standby condition, the left channel safety jection system test button was pushed to initiate a quarterly test.
is resulted in a loss of offsite power due to the spurious operation a differential relay on the 1-2 startup transformer. The actuation the relay was due to unbalanced sensing 6urrents from a current ansformer - a result of the incompatibility of the installed current ansformer with the 345 KV - 2.4 Ky step-down situation.
tive action:
he differential relays were removed from startup transformers 1-1
- 2. High-side overcurrent and instantaneous overcurrent relays were led.
purpose of failed system or component:
he differential relays provided overcurrent protection for the p transformer.
lability of system per WASH 1400: Offsite power: 2 x 10-5 /hr lability of component per WASH 1400:-
Unavailabilities are In units of per demand D-1 . Failure rates are in of per hour HR-1.
Core Test Button tion of a Dif- Safeguard Buses Damage Pushed to ferential Relay IC and ID (Due to Initiate on the 1-2 Test Button Quarterly Startup Trans- Depression)
Test former No Yes Yes No C 71694 - Actual Occurrence for Loss of Offsite Power at Palisades
______________________________________ _______________________________No No 2 No 3 Yes 4 Yes 5 No 6 No 7 Yes 8 Yes 9 No 10 Yes 11 12
-V..
13 1694 - Sequence of Interest for Loss of Offsite Power at Palisades cluded in operating procedures
NUMBER: 71694 May 26, 1972 may 17, 1972 D: Offsite power LVED: Startup transformer erly chosen differential relay TEREST: Loss of offsite power NCE: Loss of off site power during testing Palisades 255 PWR CAL RATING: 805 MWe 1.0 yr EERS: Bechtel onsumers Power Corp.
les south of South Haven, Michigan G CONDITION: Hot standby TYPE OF FAILURE: inadequate performance; (b) failed to start; (c)made inoperable; (d) ___________
OD: During testing incompatible current transformer had been installed r to criticality