LONDON – 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 that one expert called the gravest in nearly a decade.
Officials said the low-speed crash did not damage the vessels' nuclear reactors or missiles or cause radiation to leak. But anti-nuclear groups said it was still a frightening reminder of the risks posed by submarines prowling(潜行) the oceans powered by radioactive(放射性的) material and bristling with(充满) nuclear weapons.
The first public indication of a mishap(灾祸) came when France reported in a little-noticed Feb. 6 statement that one of its submarine had struck a submerged(在水中的) object — perhaps a shipping container. But confirmation of the accident only came after British media reported it.
France's defense ministry said Monday that the sub Le Triomphant and the HMS Vanguard, the oldest vessel in Britain's nuclear-armed submarine fleet(舰队), were on routine patrol(在例行巡逻) when they collided in the Atlantic this month. It did not say exactly when, where or how the accident occurred.
France said that Le Triomphant suffered damage to a sonar dome(声纳罩) — where navigation and detection equipment is stored — and limped home to its base on L'Ile Longue on France's western tip. HMS Vanguard returned to a submarine base in Scotland with visible dents(凹痕) and scrapes(刮痕), the BBC reported.
"The two submarines came into contact at very low speed," Britain's First Sea Lord, Admiral Jonathon Band, said. Band, Britain's most senior naval officer, offered no further explanation.
HMS Vanguard came into service in 1993, has a crew of around 140 and typically carries 16 Lockheed Trident D5 missiles(洛克希德三叉戟D5类导弹). Under government policy, British nuclear submarines carry a maximum of 48 warheads(弹头). At least one of Britain's four submarines is on patrol(在巡逻中) and ready to fire at any given time.
France's Le Triomphant carries 111 crew and 15 nuclear missiles, according to defense analysis group Jane's.
"This is the most severe incident involving a nuclear submarine since the sinking of the Kursk in 2000 and the first time since the Cold War that two nuclear-armed subs are known to have collided," said Kate Hudson, head of Britain's Campaign for Nuclear Disarmament.
Russia's Kursk nuclear submarine crashed to the bottom of the Barents Sea during a training voyage in August 2000, killing all 118 crew members.
In March 2007 two British sailors were killed in an explosion on board HMS Tireless during a war game beneath the Arctic ice cap. The same submarine crashed into an object, possibly an iceberg, while on patrol in the Arctic in May 2003. And in November 2002 HMS Trafalgar suffered considerable external damage after running aground on rocks off Scotland while taking part in a two-week training exercise
"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. "There is no precedent(先例) of an incident like this — it's a freak accident," he said.
Stephen Saunders, a retired British Royal Navy commodore(舰队司令官) and the editor of Jane's Fighting Ships, said that while NATO countries let each other know what general area of the Atlantic they are operating in, neither submarine would have had a precise position for the other.
"This really shouldn't have happened at all," Saunders said. "It's a very serious incident, and I find it quite extraordinary."
Both Saunders and Willett said submarines don't always turn on their sonar(声纳) systems, or make their presence obvious.
"The whole point is to go and hide in a big chunk of ocean and not be found. They tend to go around very slowly and not make much noise," Saunders said.
Willett said the greatest risks from an accident would be from a leak of radioactive waste. An accidental firing of a nuclear weapon as a result of a crash would be impossible, because of the complex processes needed to prime and fire a missile, he said.
Stephane Lhomme, a spokesman for the French anti-nuclear group Sortir du Nucleaire, said his organization is checking the French coastline for evidence of any leak of radioactive material.
"This reminds us that we could have a new catastrophe(大灾难) with a nuclear submarine at any moment," Lhomme said.