This is the same nuclear tug that has been in the news before a couple of times in the Barents Sea. Very odd. https://thebarentsobserver.com/en/nuclear-safety/2020/11/mechanical-failure-leaves-russias-new-antarctica-station-stranded-outside

Mechanical failure leaves Russia's new Antarctica station stranded outside Angola

The 32-year old nuclear-powered container ship "Sevmorput" has an unexplained breakdown causing restricted maneuverability. The ship has sailed zig-zag outside port in Angola for more than two weeks.

Something bad happened with the power transfer, marine shaft or propellers on the 260 meters long ship sailing south in the Atlantic in mid-October.

Speed was reduced on October 16 or 17. Sailing zig-zag for a day, then turned north like she was heading home, before a day later again sailing south at a reduced speed of 6-7 knots. The voyage continued along the coast of Africa, but for the last two weeks, “Sevmorput” has stayed just outside the Angolan port of Luanda. All time sailing zig-zag at the same reduced speed.

Rosatomflot has been unforthcoming about the situation and not replied to any of the questions from The Barents Observer.

A discussion group on the social media channel Vkontakte, though, provides some insight to the critical situation happening with the world’s only civilian nuclear-powered cargoship off the Angolan coast. An employee with the Russian Arctic and Antarctic Research Institute in St. Petersburg writes “there is a breakdown on the ship, as I understand it, and divers are trying to fix.” It is not clear what exactly is the trouble, but he writes something is badly wrong with the shaft, propellers or associated gear.