INES-event
INES 0

FAILURE OF 5231 CB-5 TO CLOSE DURING FAILURE 5231 DG-1 TO START WHEN STATION CLASS IV SUPPLY FAILED

Unit was under cold shutdown. Station class IV supply failed due to grid disturbance. Emergency diesel generator DG-2 came on auto while DG 1 failed to start and also class III tie breaker 5231-CB-5 between bus M and bus I did not close due to faulty breaker contacts. However, DG 1 could be started manually from field and supply and bus I could be restored. Subsequently class IV supply also could be restored from grid. Since unit was already under cold shutdown and one DG was adequate, the event was rated below scale "0".

Location: RAJASTHAN-1
Event date: Fri, 21-08-1992
Nuclear event report
Legenda & explanation