Just what caused a mysterious explosion and the deaths of five key researchers in Russia’s equivalent of Los Alamos? The accident last week caused a spike in background radiation levels and prompted a scramble of nuclear-related support to Sarov, a secret city in northern Russia known for research and development on nuclear weapons. Western intelligence suspects that the new Russian nuclear cruise missile is under development in Sarov — or was, anyway.

The Russians finally broke their silence today, but didn’t actually offer any specific denials, CNN notes:

The Kremlin broke its silence Tuesday on the apparent explosion of a nuclear-powered cruise missile during a test, saying that accidents “happen” but that Russia remained “far ahead” in the development of advanced weaponry.

Kremlin spokesman Dmitry Peskov declined to confirm widespread international speculation that the accident — which claimed the lives of at least five nuclear specialists last Thursday — involved a nuclear-powered cruise missile known as the Burevestnik or Skyfall.

But in a conference call with reporters, Peskov denied that such mishaps would set back Russian efforts to develop advanced military capabilities.

The spokesperson said that only experts could speak with authority on such matters, but added: “Accidents, unfortunately, happen. They are tragedies. But in this particular case, it is important for us to remember those heroes who lost their lives in this accident.”

Russia had ordered the nearby village of Nyonoksa to evacuate, but then inexplicably canceled the order:

The Russian military on Tuesday told residents of a village near a navy testing range to evacuate, but cancelled the order hours later, adding to the uncertainty and confusion fueled by a missile explosion at the range that led to a brief spike in radiation that frightened residents and raised new questions about the military’s weapons program.

The initial notice from the military told residents of Nyonoksa, a village of about 500, to move out temporarily, citing unspecified activities at the range. But a few hours later, the military said the planned activities were cancelled and rescinded the request to leave, said Ksenia Yudina, a spokeswoman for the Severodvinsk regional administration.

The Associated Press suggests in the same report that this might have been a routine request:

Local media in Severodvinsk said residents of Nyonoksa regularly received similar temporary evacuation orders usually timed to tests at the range.

Even that seems significant, however. If they had a test planned and then canceled it, it might be because their nuclear facilities can no longer conduct tests. Or, alternately, the Putin regime figures they can sacrifice 500 of their citizens in order to maintain the Chip Diller routine.

That would be a long-term mistake. The Chernobyl disaster in 1986 didn’t lead immediately to the collapse of the Soviet system, but it certainly contributed to the erosion of its credibility and hastened its end. The Washington Post’s editorial board offered Russia a reminder of that this afternoon and told Vladimir Putin to ‘fess up:

Initially, Russia’s defense ministry said two people died in the explosion, three were injured and there was no radiation release. Then officials in Severodvinsk, a larger city some 19 miles away, posted on its website a statement that sensors recorded a short-term spike in radiation, without saying how much. The report was subsequently taken down. Residents rushed to stockpile iodine against possible radiation exposure. Ambulances carrying the injured appeared to be sealed by some kind of plastic film, and personnel were wearing hazmat suits. On Aug. 10, the Russian state nuclear agency, Rosatom, said five of its employees had died in the accident, bringing the total to seven. Moreover, Rosatom said the blast resulted from the test of a jet engine “propulsion system involving isotopes,” or nuclear materials. On Aug. 13, residents of the small village of Nyonoksa were told they would be evacuated temporarily.

If this slow dribble of facts sounds familiar, it is — the same parade of misdirection happened during the Chernobyl nuclear disaster in 1986. This accident is nothing like Chernobyl in scale, but the government response looks familiar, including a lack of transparency about radiation release. As the recent television series “Chernobyl” vividly illustrated, that accident, the worst in the nuclear age, was characterized by lies and deception. At the very least, Russia should immediately clear up what occurred at Nyonoksa.

They also raise the warning for the rest of us:

If the Nyonoksa blast was a test of the Burevestnik engine, Russia may be further along than previously thought. Mr. Putin has taken pains to brag that Russian can develop weapons with an asymmetric threat to the United States. Test failures are to be expected. But at a time when nuclear arms control is falling apart, this test raises a question: If successful, what kind of new nuclear threat will Russia possess?

Maybe it wasn’t so successful, which might be why Putin’s not talking much about it.

Update: According to an ABC source, the US is pretty convinced this was related to the development of the nuclear cruise missile. Another says that it’s likely never going to work for Putin and that more such failures can be predicted:

The explosion in northern Russia last week that killed 7 people “likely” involved Russia’s new nuclear-powered cruise missile, a U.S. official said. Russian authorities have given conflicting information about the explosion and whether it was triggered by testing of the missile, which is intended to fly long distances and go around air defense missile systems. …

Russia has never given details on how the the new missile works but most arms experts believe it is a so-called ramjet—that is an engine that works by sucking in air, heating it and then releasing it out the back to create propulsion. The miniature nuclear-reactor heats the air.

The United States abandoned the development of a similar program in the 1960’s, leading outside experts to question whether the concept of a nuclear powered missile is feasible.

Cheryl Rofer a veteran scientist who formerly worked at Los Alamos Laboratory and who said she had been personally acquainted with the U.S. ramjet program, in a blog post Sunday wrote that the Kremlin had likely been persuaded to back an unrealistic program.

“I think that what has happened is that someone sold a program to Putin. The visuals are cool, and the idea of a cruise missile that can just keep cruising obviously appealed to him. The promoter of the program may even believe in it,” Rofer said. “ I’m saying I think they’ll never have an operating system.”