ML20168A435

Final ASP Analysis - Browns Ferry 1 (LER 259-73-LTR-1)

ML20168A435
Person / Time
Site:	Browns Ferry
Issue date:	06/16/2020
From:	Christopher Hunter NRC/RES/DRA/PRB
To:
Littlejohn J (301) 415-0428
References
LER 1973-001-00
Download: ML20168A435 (4)

Text

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e: Complete Loss of a.c. Power Causes RCIC and HPCI to be Inoperable.

failure sequence was:

In preparation for the turbogenerator trip and loss of offaite power test, the 4 kv unit boards were plated in maual to prevent automatic transfer.

The turbine was manually tripped because of increased vibration.

This resulted in a scram since offsite power could no longer be supp-lied, (because of lY The RCIC and the HPCI systems could not be started until the standby diesels were energized, since their rest logic required a.c. power.

ective action:

The power source for some RCICIHPCI relays was changed and the anual reset was eliminlated.

gn purpose of failed system or component:

CIC provides a source of water should the reactor become isolated.

PCI provides a high pressure coolant supply during a small LOCA.

ailability of system per WASH 1400:- RCIC: 8.0 x 10-2 /1)

IIDCI: 8.8 x lO7 2 /ID ailability of component per WASH 1400:

Unavailabilities are in units of per demand D-1. Failure rates are In s of per hour 1R-1 .

A

~- No i

1 Yes Yes No 566 - Actual Occurrence of Complete Loss of Plant A.C. Power Causes RCIC and HPCI to be Unavailable

Yes 2 No 3 Yes 4 Yes 5 No 6 Yes Yes 8 No 9 Yes 10 No 11 Yes 12 Yes 13 Yes 14 Yes 15

- Sequence of Interest for Complete Loss of Plant A.C. Power Caused RCIC and HPCI to be Inoperable at Browns Ferry 1

NUM-'BER: 85566 November 19, 1973

RCIC/IiPCI VED: RCIC/HPCI tripping logic error EREST: Loss of Feedwater Flow CE: Complete Loss of a.c. Power Causes RCIC and HPCI to be inoperable.

Browns Ferry 1 259 BWR AL RATING: 1065 e 18 yr al Electric EERS: TVA TVA iles NW of Decatur, AL CONDITION: Just scrammed during testing TYPE OF FAILURE: (a) inadequate performance; (b) failed to start;

@Omade inoperable; (d) ___________

D: Operational Event.

n Mode Design Error, a.c. requirement.