Russia tested four of the missiles between November and February, each resulting in a crash, people who spoke on the condition of anonymity previously told CNBC. The U.S. assessed that the longest test flight lasted just more than two minutes, with the missile flying 22 miles before losing control and crashing. The shortest test lasted four seconds and flew for five miles. Russia has denied the missile test failures.
If the Russians are able to regain possession of the missile, U.S. intelligence analysts expect Moscow will use the procedure as a blueprint for future recovery operations. It is unclear whether the other missiles are missing at sea, too.
While the report didn't address the potential effects of possible damage to the weapon's reactor, there remain concerns that radioactive material could leak.
"It goes without saying that if you fire a missile with a nuclear engine or energy source, that nuclear material will end up wherever that missile ends up," said Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists.
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"If this missile was lost at sea and recovered in full, then you might hypothetically be able to do it without pollution, I would have my doubts about that because it's a very forceful impact when the missile crashes. I would suspect you would have leaks from it," Kristensen added.
The weapon, which has been in development since the early 2000s, is believed to use a gasoline-powered engine for takeoff before switching to a nuclear-powered one for flight, sources have said.