Subs of Britain, France collided

Nuclear submarines from Britain and France collided deep in the Atlantic Ocean this month, authorities said Monday in the first acknowledgment of a highly unusual accident.

Officials said the low-speed crash did not damage the vessels’ nuclear reactors or missiles or cause radiation to leak. But antinuclear groups said it was still a frightening reminder of the risks posed by submarines powered by radioactive material and bristling with nuclear weapons.

France’s Defense Ministry said Monday that the sub Le Triomphant and the Vanguard, the oldest vessel in Britain’s nuclear-armed submarine fleet, were on routine patrol when they collided in the Atlantic. It did not say exactly when, where or how the accident occurred.

France said that Le Triomphant suffered damage to a sonar dome -- which contains navigation and detection equipment -- and limped home to its base on L’Ile Longue on France’s western tip. The Vanguard returned to a submarine base in Scotland, with visible dents and scrapes, the BBC reported.

“The two submarines came into contact at very low speed,” Britain’s First Sea Lord, Adm. Jonathon Band, said. Band, Britain’s most senior naval officer, offered no further explanation.

The Vanguard came into service in 1993, has a crew of around 140 and typically carries 16 Lockheed Trident D5 missiles. Under government policy, British nuclear submarines carry a maximum of 48 warheads. At least one of Britain’s four submarines is on patrol and ready to fire at any time.

France’s Le Triomphant carries 111 crew members and 15 nuclear missiles, according to the defense analysis group Jane’s.

“It’s an absolute one in a million chance that the two submarines were in the same place at the same time,” said Lee Willett, head of the maritime studies program at the Royal United Services Institute, a London-based military think tank.

He and Stephen Saunders, a retired British Royal Navy commodore and the editor of Jane’s Fighting Ships, said submarines don’t always turn on their sonar systems, or make their presence obvious.