A French soldier engaged in Operation Chammal, a French military operation within Operation Inherent Resolve, the international coalition against the Islamic State (IS), stands guard in front of an artillery truck on Saturday near Al-Qaim, a few kilometers from the last scrap of territory held by IS in eastern Syria. Photo: AFP

A fire that raged for 14 hours on one of France's nuclear submarines did not lead to an atomic accident as steps were taken to protect its reactor, the defense minister said Saturday.

The submarine was under renovation in the southern base of Toulon when the blaze broke out at about 10:30 am (0830 GMT) on Friday in a hard-to-access part of the lower bow section, the navy said. 

It then took around 100 firefighters and 150 support crew to put out the blaze by around midnight (2200 GMT Friday), the navy said in a statement.

"There was a fire, but no, there was not a nuclear accident," Defense Minister Florence Parly said.

Parly added that during the fire "measures were taken in the rear area to protect the nuclear reactor compartment."

The navy said earlier there were no casualties and no risk of radiation because the nuclear fuel had been removed during the renovation of La Perle (The Pearl), one of France's six nuclear attack submarines.

The extent of the damage was not immediately clear but an official with the Naval Group repair center called the incident "serious."

The regional authorities said that pollution and radioactivity tests carried out by independent experts had not found anything out of the ordinary.

But French nuclear watchdog association CRIIRAD said that a nearby measurement found that radioactivity levels had oscillated at low levels for a few hours in the days leading up to the fire.

AFP