Fire at a generator of a power plant

A malfunction in the turbine-generator unit resulted in a fire and forced the operators to manually shut down the nuclear reactor. The seals containing the hydrogen hydrogen used as a coolant 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.

The loss 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.

Turbine generator, generator coolant, hydrogen seals

DESCRIPTION OF THE FACILITY
The fire occurred in the turbine hall on a 2,106 MW power pant.
There were 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.

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.
The NRC said all nuclear safety systems functioned as expected and were not affected by the fire, which occurred in a building separate from the nuclear reactor.

The NRC said all nuclear safety systems functioned as expected and were not affected by the fire, which occurred in a building separate from the nuclear reactor.

The fire was extinguished 25 minutes after it started.. The operators manually shut the reactor.
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.

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.