Mazurenko told the BBC decades later that he had been chatting with other crew members during what had been an otherwise uneventful few days at sea, when other sailors came charging from the sub’s reactor compartment, where radiation monitors had just begun to blare.

Checking other onboard radiation monitors revealed a horrifying truth — levels were off the charts. The sub’s first of a kind liquid-metal cooled reactors had begun to leak. Within hours, those who hadn’t fled the reactor compartments had to be carried.

The sub reversed course made the five-hour journey back to base on the Kola Peninsula but by then the damage had been done. Radiation levels on the vessel were so high they even set off radiation monitors at dockside.  Within days, nine of the 144 crew members would die of radiation sickness, with many others perishing of related illnesses in the following years.

The reactors had been unsafe since the K-27 was launched in 1962, but what turned out to be a massive coolant failure finally led to their demise. After determining that it would be too expensive to fix, the sub’s irradiated carcass —its reactors still loaded with highly enriched uranium fuel — was eventually scuttled in the shallows off the Novaya Zemlya Archipelago in the Kara Sea in 1982.

And it is there that the sub has laid ever since, joining an array of other nuclear reactors and similar radioactive castoffs that Moscow has no real plan to clean up — especially after its invasion of Ukraine.

This is the subject of a new Bellona online presentation based on our new report, The nuclear legacy of the Russian Arctic, which will take place Tuesday, May 14 at 14:00 Central European Time (Click to register).

“As Russian money goes to war instead of environmental protection, the Russian Arctic remains a radiation threat,” says Bellona’s Alexander Nikitin, a former Soviet submarine captain who authored the report.

While the K-27 has been identified by Russian authorities as the most dangerous radioactive relic of the Cold War sunk in the Arctic, there are some 1,000 other sea and land-based hazards that, before the war, had been prioritized for cleanup.

These plans, however, were being developed among a cooperative of European nations, namely Norway, whose funding and technological assistance would have been essential to Moscow to complete the job. But the Kremlin’s February 2022 invasion of Ukraine has cut it off from international cooperation.

And though Moscow insists it will carry on the cleanup on its own, the limping progress it has made since the invasion commenced makes its claim doubtful.  For instance, Nikitin estimates that the Russia government will need to spend 100 million Euros to complete the rehabilitation of Andreyeva Bay — a derelict former submarine refueling site that was once the crown jewel of Russian-Norwegian nuclear cleanup projects.

The Andreyeva Bay cleanup, which after decades of pressure and negotiation, began in 2017 was to be completed by 2028. Now, however, the Russian government doesn’t estimate that the work will be completed before the 2030s — if even then.

So what will come of these projects now that they have become yet another casualty of the war in Ukraine? Join us in our discussion Tuesday to find out more.