The submarine K-27 was scuttled by the Soviet Union with the reactor not dismantled, which could pose a risk of radioactive leakage as much as the Chernobyl disaster.
At the height of the Cold War in 1968, 144 Soviet sailors aboard the submarine K-27 sailed to the North Pole on a mission to gather information about NATO bases. They did not know that they were about to face a radioactive disaster in the seabed, according to the BBC.
The K-27 is the only Project 645 attack submarine, developed from Project 627 (NATO designation: November). Like the United States, the Soviet Union often experimented with advanced technologies that were ahead of their time. K-27 is equipped with two liquid metal cooled VT-1 nuclear reactors . This is a design never seen on a Soviet submarine, making the K-27 more of a science project than an attack submarine.
When launched on June 15, 1958, K-27 was the first Soviet submarine to own a nuclear reactor cooled by a liquid metal mixture of lead and bismuth. Reactors of this type are small in size and have a larger capacity than traditional water-cooled designs. It helps submarines stay hidden for weeks in the sea without needing to surface or refuel. The K-27 set an impressive record in the Soviet navy, becoming the first nuclear attack submarine to remain submerged for 50 days continuously.
Despite its impressive technology and specs, the K-27 had a short operating life due to nuclear reactor failure. On May 24, 1968, during an expedition to the North Pole, one of the VT-1 reactors crashed, causing the ship’s power supply to suddenly decrease from 87% to 7%. At the same time, gamma radiation spiked in the reactor chamber. Toxic gases and steam also leaked from the reactor into other compartments.
K-27 during an exercise near NATO forces. (Photo: The Lean Submariner).
“After 5 days of journey, everything went back to normal. I was chatting with the others in the 5th compartment, next to the 4th compartment containing the two nuclear reactors, when suddenly I heard someone running. We have radiation detectors but they don’t turn on, no one cares about the parameters until the technician turns on the radiation meter. His face was shocked and full of worry,” recalled submarine officer Vyacheslav Mazurenko.
The crew did not understand the severity of the problem until it was too late, because the radioactive gas had no taste. Two hours after the initial alarm, the occupants of compartment 4 had to be carried out on stretchers due to severe radiation exposure. The crew managed to get the ship to surface, then it took 5 hours to bring the ship back to the base on the Kola peninsula.
“When the ship surfaced, the superiors ordered to turn off the engines and wait for special instructions. However, Captain Pavel Leonov decided to continue the journey. If stopped for a few more hours, no one would survive to bring the K-27 back to base,” Mazurenko said.
All 144 sailors on board were radioactive, of which nine died. However, the Soviet Union continued to send the K-27 to sea a month later and conducted many experiments until 1973.
By February 1979, the Soviet army decided to remove the K-27 border, but had a headache to find a way to handle the nuclear reactor on the ship. They finally decided to scuttle the K-27 in 30m deep water in the Kara Sea on September 6, 1982.
The K-27 compartment is filled with concrete and asphalt to seal the two reactors and 90 kilograms of uranium-235 fuel inside, but this protection is expected to last for only 50 years. By the middle of this year, the concrete shell and asphalt on the ship only had a useful life of about 15 years. That makes K-27 like a Chernobyl disaster under the sea waiting to happen.
Ship K-27 in the process of being sunk. (Photo: Barents Observer).
“Sooner or later, a radioactive leak will happen if the K-27 is left lying there. The ship has been sitting in the sea for more than 30 years in a state of rust. The challenge now is to find a way to bring the ship up without causing the reactors to shake much. If that happens, an uncontrolled chain reaction could be triggered, causing large amounts of radioactive material to leak into the Arctic marine environment. This type of pollution cannot be removed from the seabed,” said Thomas Nilsen, editor-in-chief of the Barents Observer.
Despite the incident on the K-27, the liquid metal cooled reactor was still completed and equipped for the Project 705 “Lira” submarine (NATO designation: Alfa). They have unprecedented speed and incredible deep diving ability. However, all 7 Lira submarines were scrapped early due to expensive maintenance costs.
The United States also installed liquid metal-cooled nuclear reactors on the submarine USS Seawolf (SSN-575) in the 1950s, but it quickly phased out them in favor of a high-pressure water reactor.