Andrei Pronin / AP file
The Yekaterinburg nuclear submarine is in Gadzhiyevo in the Murmansk region, Russia, on March 16, 2011. Firefighters extinguished a massive fire aboard a docked Russian nuclear submarine Friday, Dec. 30, 2011, as some crew members remained inside, officials said, assuring that there was no radiation leak and that the vessel's nuclear-tipped missiles were not on board.
MOSCOW -- Russia came close to nuclear disaster in late December when a blaze engulfed a nuclear-powered submarine carrying atomic weapons, a leading Russian magazine reported, contradicting official assurances that it was not armed.
Russian officials said at the time that all nuclear weapons aboard the Yekaterinburg nuclear submarine had been unloaded well before a fire engulfed the 550-foot vessel and there had been no risk of a radiation leak.
But the respected Vlast weekly magazine quoted several sources in the Russian navy as saying that throughout the fire on Dec. 29 the submarine was carrying 16 R-29 intercontinental ballistic missiles, each armed with four nuclear warheads.
"Russia, for a day, was on the brink of the biggest catastrophe since the time of Chernobyl," Vlast reported. The 1986 disaster in modern-day Ukraine is regarded as the world's worst nuclear accident.
Neither the Russian Defense Ministry nor the office of Deputy Prime Minister Dmitry Rogozin, who has responsibility for military matters, would immediately comment on the report. A spokesman for the navy could not be contacted.
Senior U.S. officials told NBC News on Tuesday that the report is true and that nuclear arms were onboard Dec. 29, but there was no danger of a catastrophic disaster on the scale of Chernobyl.
The reason, said one official, is that the fire was not near the weapons or the ship's reactor and that those areas are hardened.
The fire started when welding sparks ignited wooden scaffolding around the 18,200-ton submarine at the Roslyakovo docks, 900 miles north of Moscow. It is one of the main shipyards used by Russia's northern fleet.
Russia Today File / AFP - Getty Images
A grab from images released by Russia Today shows fire crew trying to extinguish a fire on board the Russian nuclear submarine Yekaterinburg docked in Murmansk on Dec. 29, 2011.
The rubber covering of the submarine then caught fire, sending flames and black smoke 30 feet above the stricken vessel. Firemen battled the blaze for a day and a night before partially sinking the submarine to douse the flames, according to media reports.
Vlast reported that immediately after the fire, the Yekaterinburg sailed to the navy's weapons store, an unusual trip for a damaged submarine supposedly carrying no weapons and casting doubt on assurances that it was not armed.
"K-84 was in dock with rockets and torpedoes on board," the magazine said, adding that in addition to the nuclear weapons, the submarine was carrying torpedoes and mines as well as its two nuclear reactors.
The magazine said that if one of the torpedoes had exploded, it could have threatened the nuclear missiles, leading to a nuclear accident.
Media reports of what happened at the time of the fire were contradictory, and foreign journalists were unable to gain access to the high-security zone.
An official told NBC News on Tuesday that even if the nuclear warheads had caught fire, the physics of nuclear weapons don't lend themselves to accidental detonation.
Although the probability of a disaster was low, there is a high probability that someone in command will have to answer questions, the officials said.
It is standard operating procedure in the world's nuclear navies to remove nuclear warheads from submarines prior to maintenance.
Russia's worst post-Soviet submarine disaster was in August 2000 when the nuclear submarine Kursk sank in the Barents Sea, killing all 118 crewmen aboard.
NBC News' Robert Windrem contributed to this report from Reuters.
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