At 10 am, 2 employees in a thermal power plant noticed a leak on the fuel supply return circuit of unit no. 6 (G6) located in the basement. The driver changed the fuel (heavy fuel oil with domestic fuel oil), to prevent the cylinders from clogging, before shutting down and switching over the G5/8 unit to safety mode, with 44 MW of power. The domestic fuel oil that was projected on the engine’s right-hand turbo, via the crack in the pipe, caught fire at 10.05 am, forming a fireball probably caused by ignition of the fuel oil spray. Technicians attempted to contain the fire using extinguishers, but the fire quickly spread. At 10.07 am, they alerted the fire brigade and started up the fire protection motor-driven pump located in the basement. The driver shut down the 3 other units for plant unit 5/8. At 10.12 am, the emergency services fought the fire using a nozzle on G5 and G6 and cooled G7 and G8. The driver shut down the booster pumps on G5/8. At 10.20 am, the fire spread to G7 and G8 releasing a thick cloud of smoke. At 10.30 am, the driver shut down plant unit 1/4 and evacuated the control room. The internal emergency plan was implemented. To avoid any pollution of the water, the ultimate barrier valve was closed. A neighbouring establishment provided extra extinguishing foam. The “superheated water” valve was closed. The fire was contained at 11.20 am and extinguished at 2.21 pm after cables had caught fire again. Streaks of HC, the presence of 12m³ of oil, drained from the unit and stored on a tank in view of its servicing, fire doors open, impossible access to shutdown controls and to the isolation valves between the modules and the fuel ramps due to the flames and deterioration of the spool piece contributed to fuelling and spreading of the fire. The automatic fire extinguishing system did, however, help to prevent the spread of flames to the top floors. During the operations, the emergency services secured the outside domestic fuel oil tanks located close to the buildings.

2 employees were taken to hospital: one with minor arm burns and the other overcome by smoke inhalation. The fire spread to the external buildings destroying the control room, the rooms housing the compressors and the emergency generator. Plant unit 5/8 was unavailable for 12 to 14 months and loss of production occurred but users experienced no power cuts. The crack on the pipe had been caused by motor vibrations. This problem had already been identified, and vibratory disconnection hoses were installed …

The inspection authority drew up a report establishing the facts, and the power plant had already been subject to a Prefectural order for formal notification for non-compliance of safety-related provisions. The operator remembered that fire prevention actions were not always applied and proposed material and organisational corrective actions.