Russian ship exploded in Mediterranean ‘carrying nuclear reactors to North Korea’

A mysterious tale of geopolitics, espionage and shipwrecks

An investigation carried out by CNN, which looked into the sinking of the Ursa Major, found reason to believe the vessel was carrying components for two nuclear reactors intended for submarine use.

However, the boat, which set off from St Petersburg and sank 60 miles off the coast of Spain never made it to its supposed destination of the port of Rason in North Korea.

A mystery all at sea

Two days before Christmas Day 2024, the Ursa Major sank off the coast of Spain, after veering off course and suffering three explosions on its starboard side near the engine room which killed two crew members.

The boat was being escorted by two Russian Navy ships.

The ship had issued a distress call at 11:53am and later started to list heavily to its side.

Spanish authorities managed to rescue 14 crew from the ship before an inspection of the vessel which found containers filled with rubbish, fishing nets and equipment.

A later investigation found a 50cm-by-50cm hole in the boat's hull with the metal bent inwards.

The direction of the metal bent inwards suggests an external impact on the hull.

CNN's investigation suggests that the damage could have been inflicted by a high-speed "supercavitating" torpedo which only the US, Russia, Iran and a handful of NATO allies are thought to have access to.

The nuclear factor

While it's unlikely we'll ever know the true reason for the sinking of the Ursa Major, the motive does indeed make sense.

After the 14 remaining crew were brought ashore in Spain, the captain told investigators that the ship was carrying components for nuclear reactors, after originally describing them as "manhole covers".

"He finally confessed that they were the components of two nuclear reactors similar to those used by submarines," the CNN report says, "according to his testimony, and without being able to confirm it, they did not contain nuclear fuel.”

CNN also reported that in October 2024, the ship's owner, the state-linked Oboronlogistics, said in a statement that their vessels had been licensed to carry nuclear material.

They later described the sinking as a “targeted terrorist attack”.

The wreck of the Ursa Major

After suffering these explosions, the Ursa Major eventually sank to the ocean floor, along with it potential evidence of a nuclear reactor.

Since the sinking, a sophisticated “nuke sniffer” aircraft, known as a WC135-R and based in the US has twice flown over the wreckage site - once on August 28 last year and again on February 6 this year, according to publicly available flight data.

CNN reported also that the Yantar, officially a Russian research ship which has often been accused of espionage, sat over the Ursa Major’s wreckage for five days before four more explosions were detected, possibly targeting the remains of the ship on the seabed.

Despite the evidence pointing towards an incident that involves more than meets the eye, investigators have also doubted the story, notably questioning why Russia would transport such cargo around the western Europe by boat, instead of using their rail network which has a direct link.