Severity
Incident
Leak
Yes
Ignition
Yes
Ignition Source
self-ignition due to gas friction; mechanical friction or electric current

Severe vibrations caused by broken low-pressure turbine blades damaged the main turbine generator at a nuclear power plant. These vibrations also caused multiple hydrogen leaks at equipment connections to the generator, resulting in hydrogen flames outside of the generator casing that caused minimal damage to the facility. Hydrogen is used to internally cool the plant's electric generators. Water from the fire suppression system and oil released from the turbine lube oil system during the event were contained within the plant, resulting in no impact to the environment. The plant's nuclear systems were unaffected by the event.

Incident Date
Sep 20, 2008
Setting
Equipment
  • Cooling Equipment
  • Main Generator Stator Cooling Water System
Damage and Injuries
Contributing Factors
When Incident Discovered
Lessons Learned

The turbine components that caused the vibrations were a retrofit design which had been in service for about two years and were under warranty from the vendor. The root cause analysis of the event determined that the damage was caused by a defect in the design or assembly of the turbines.