Hydrogen Fire in a Power Generator
A malfunction in the turbine generator resulted in a fire and caused the operators to manually shut the reactor. The turbine generator transforms steam into electricity and hydrogen is used as a coolant of the bearing of the generator. The seals containing the hydrogen were likely damaged by abnormal turbine vibrations.The damage to the turbines and generator from the fire was minimal, but vibrations did damage the low pressure turbines, bearing supports and some steam piping.
Event Date
September 20, 2008
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
The loos of containment of the hydrogen coolant was caused by the vibrations in the turbine, due to an imbalance from the loss of turbine rotor blades.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
Turbine generator, generator coolant, hydrogen seals
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
The fire occurred in the turbine hall on a 2,106 MW power pant. There are two units at the station: 1,029 MW and 1,077 MW . Unit 2 continued to operate at full power.The turbine generator transforms steam into electricity. Hydrogen is used to keep the generator cool during operation and the hydrogen is contain in seals.
Lessons Learned
Lessons Learned
As reported by the Nuclear Regulatory Commission inspection report (see References), corrective measures were requested to the plant operator, regarding fire control systems and power plant shutdown procedures. None of them however, regarded the hydrogen system management.
Event Nature
Emergency Action
The fire was extinguished 25 minutes after it started.. The operators manually shut the reactor.
Emergency Evaluation
After the fire was extinguished, operators received a signal indicating a problem with the fire suppression system due to a rupture in the pipe that is a source of water for the plant's fire protection systems, the NRC said. Alternate sources of water were available for fire suppression in case they were needed.
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Reuter news of 20 September 2008
Investigation of the US Nuclear Regulatory Commission