Fire at a generator of a power plant

The incident occurred at the power generator of a nuclear power plant, in a non-nuclear area of the plant. Although hydrogen was use in the system, it was not affected by the fire.
Oil leaked at a bearing seal between rotor and stator of an alternator. The ignition of the leaking oil, fed by a 60 m³ tank, caused the defect of the turbine and the automatic shutdown of the nuclear unit.
The operator started the emergency plan after 35 minutes and the departmental operational centre was alerted after 50 minutes. The engine room was evacuated and a security perimeter was set up.
The operator purged the hydrogen of the alternator cooling circuit. Public firefighters and the site fire team extinguished the fire around after approximately 1.5 hours by means of foam lances. This allowed to stop oil leak.

bearing seal, rotor and stator of an alternator, non-radioactive area

automatic shutdown of the nuclear unit

The operator triggered his emergency plan at 13:23 and the departmental operational centre (COD) was activated at 13:45. The engine room was evacuated and a security perimeter was set up. The operator purged the hydrogen of the alternator cooling circuit (H2 circulated between the rotor and the stator, used as coolant and itself cooled by a water circuit) at 13:17. Public firefighters and the site fire extinguished the fire around 15:30 with foam lances and the oil leak is stopped at 16:05. The emergency plan was raised at 17:15 and the COD at 16:55.

This is an incident with a conventional oil fire, in presence of a subsystem (hydrogen coolant of the alternator) which was not affected. It is the only HIAD incident, among those related to turbine-generator failures, which did not bring to hydrogen fire. Safety systems worked as expected.