TL;DR some people doing a radar survey didn't know about Camp Century and were surprised/interested when it showed up in their data.
TFA is just a re-write of existing journalism from last week but with more sensationalist language. Most recently discussed here:
Sometimes I read the headlines and then click on the story and the headline here doesn't match the story. Maybe it's Google translate losing the thought? But in this case they match exactly! Nice!
For those most-interested in the "nuclear" part of the title:
> As a result, the site — along with its 200,000 liters of diesel fuel, 24,000,000 liters of biological waste, and 1.2 million units of radioactive waste — was left behind, forever buried in the snow.
Not sure how much a "unit" of radioactive waste is here. The site had a PM-2A "portable" reactor, which was removed during decommissioning.
https://en.wikipedia.org/wiki/Camp_Century
https://en.wikipedia.org/wiki/Project_Iceworm