Spanish Probe Links Sunken Russian Ship to North Korean Nuclear Submarine Parts

A Russian cargo ship that sank off Spain in December 2024 was likely carrying components for two submarine nuclear reactors, possibly destined for North Korea, Spanish investigators concluded in findings now roiling nuclear non-proliferation circles.cnn +1 The vessel, Ursa Major, went down after a series of unexplained explosions about 60 nautical miles south of Cartagena, killing two crew members and leaving its sensitive cargo on the seabed at a depth of roughly 2,500 meters.nknews +1

Spanish authorities later told lawmakers that the ship’s captain had admitted the cargo included “components for two nuclear reactors similar to those used in submarines.”cnn Russia’s state-linked owner, Oboronlogistika, has called the incident “an act of terrorism.”united24media

What Investigators Think Was Really on Board

Initially declared to be carrying 129 empty containers and two port cranes from St. Petersburg to Vladivostok, Ursa Major was photographed shortly before sinking with two massive, tarp-covered objects on its stern, each estimated at 65–70 tonnes.asatunews +1 Spanish investigators, drawing on imagery and technical assessments, concluded the shapes and weight were consistent with VM‑4SG naval reactor casings and associated piping taken from decommissioned Russian submarines — likely unfueled but still radioactive.asatunews +1

Local newspaper La Verdad reported those components were believed to be bound for North Korea’s port of Rason, where they could support Pyongyang’s push for nuclear‑powered submarines.asatunews +1 That assessment dovetailed with recent North Korean displays of new submarine hulls and growing military cooperation with Moscow.eurasiantimes However, no physical evidence has been recovered or independently inspected, and some experts have stressed that the public case rests largely on imagery analysis and testimony rather than verified material samples.euronews

Mystery Explosions and a Deep-Sea Standoff

The cause of the sinking remained contested. Spanish seismic sensors registered three small underwater blasts shortly before Ursa Major disappeared, and investigators documented a 50-centimeter square hole in the hull with metal bent inward, damage they said was compatible with a high‑speed external weapon such as a supercavitating torpedo.asatunews Russian officials and the owner branded the incident a “targeted terrorist attack” but offered no public evidence pointing to a perpetrator.united24media

Within weeks, the Russian intelligence-gathering ship Yantar visited the wreck site, and Spain later confirmed that additional underwater explosions were recorded while it was on scene.asatunews +1 At least two flights by a U.S. WC‑135 “nuke sniffer” aircraft over the area underscored Western concern about any potential radioactive release or covert salvage.cnn Madrid has told parliament that examining or raising the wreck is “inviable” with its own resources, leaving competing powers to monitor or work around a nuclear‑sensitive site in international waters.cnn +1

The Bigger Picture

If naval reactor technology was indeed en route from Russia to North Korea, the operation would represent a dramatic breach of nuclear propulsion taboos and a leap forward for Pyongyang’s undersea capabilities, with direct implications for South Korea, Japan and the United States.kyivindependent +1 Yet the case remains shrouded in secrecy, with no international forensic report, no confirmed chain of custody and no public acknowledgment from Moscow or Pyongyang. That ambiguity leaves the Ursa Major as both a warning sign — of how far sanctions‑busting “shadow fleets” may go — and a live mystery on the Mediterranean seafloor.