An accident which killed two submariners under the Arctic icecap was unique in the Royal Navy, the ship's commanding officer has said.
An injured submariner put out several fires in the compartment
Anthony Huntrod, from Sunderland and Paul McCann, from Halesowen died when an oxygen device exploded on board the Devonport-based HMS Tireless in March.
Commanding officer Iain Breckenridge said the submarine would be undergoing repairs for minor damage.
A Board of Inquiry is being held into the cause of the accident.
The submarine was on a joint British-US operation near Alaska when air-purification equipment, known as a self-contained oxygen generation candle, exploded in a compartment above the sleeping quarters.
Mr Huntrod, 20, an operator maintainer and 32-year-old Mr McCann, leading operator mechanic were killed in the blast.
Cdr Breckenridge paid tribute to a third sailor who was injured but managed to put out several small fires in the compartment.
"He recovered himself despite his injuries, placed an emergency breathing mask on his face and in complete darkness and zero visibility, due to the smoke, extinguished the numerous small fires in the compartment and allowed access to the fire fighting and medical teams."
The sailor was airlifted to a US military hospital in Alaska and flown back to the UK after being released.
The oxygen device was restricted on other vessels as a precaution
The piece of air-purification machinery thought to have failed was fitted as part of an update to HMS Tireless in 2001.
The system, which does not provide the submarine's main oxygen supply, is in the forward escape compartment - a "quiet" area at the front of the vessel, where submariners go to relax when they are not on duty.
A Ministry of Defence spokesman said its use on other vessels had been restricted as a precaution until safety checks were carried out.
Cdr Breckenridge said all of the Tireless crew had acted professionally and calmly throughout the incident, which had happened in one of the ship's most demanding environments.
He said despite the front end of the submarine being full of smoke, the incident was contained within minutes and it surfaced safely within an hour. He described the Trafalgar Class submarines, of which the Tireless is one of seven, as the safest and most capable submarines in the world.
"This explosion is a unique incident in a submarine of the Royal Navy and it is a testament to the design, construction and maintenance that despite this event and the small fire that ensued, no serious damage was done."
The ship underwent a six-day journey under the ice after the accident without any problems, he said.