STUTTGART, Germany — The French Navy’s nuclear submarine Perle has returned to sea following just about a year of work to repair its fire-damaged body and splice it together with a second boat.

In late October, the 26-year-old nuclear attack submarine departed Cherbourg Naval Base, where it has been undergoing repairs by manufacturer Naval Group since October 2020, and returned to the service’s main base in Toulon, French Ministry of Defense spokesman Hervé Grandjean told reporters.

The nuclear attack submarine caught fire while undergoing maintenance in June 2020 in Toulon, and burned for 14 hours. The fore of the submarine suffered the most damage, while the aft of the ship, which houses the nuclear power plant and propulsion, was left intact.

French Minister of Defense Florence Parly announced in October 2020 that Naval Group would repair the ship by cutting the Perle’s aft away, and attaching it to the front part of the Saphir, a nuclear submarine that was withdrawn from service in 2019.

Grandjean confirmed that the repairs, which began Oct. 14 2020, had been successful, and that the Perle would now return to its scheduled maintenance that was ongoing at the time of the fire. The submarine was originally expected to reenter service in 2022; now, it is scheduled to return just one year later. The enhancements made to the boat throughout the repairs will extend its service life for another decade past 2023, per the French defense ministry.

The work cost about €110 million (U.S. $127.6 million), with Naval Group responsible for about €50 million, and the French government covering €60 million, Grandjean said. It required about 350,000 hours of work, including about 100,000 hours of studies, and about 300 Naval Group employees worked on the repairs while also ensuring that the next-generation Barracuda nuclear submarine program was not impacted, he noted.

Despite being half-Saphir, the boat will remain known as Perle, he added. “It is a submarine that was wounded, but not dead,” he said.

The investigation into the cause of the June 12 2020 fire is ongoing, Grandjean said. Since then, the navy has taken additional measures to avoid another such accident, and plans to budget a few million euros annually to reinforce fire detection systems on its submarine fleet, and conduct regular training events between naval firefighters based in Marseille, and private-sector industrial firefighters.

Vivienne Machi is a reporter based in Stuttgart, Germany, contributing to Defense News' European coverage. She previously reported for National Defense Magazine, Defense Daily, Via Satellite, Foreign Policy and the Dayton Daily News. She was named the Defence Media Awards' best young defense journalist in 2020.

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