It may or may not be factual in nature.
What you have is a lead-in story from a Austrian film producer who took some reports that existed a the end of WW II, and has pieced together this story of the Nazi war machine....putting a nuke weapon program into St Georgen an der Gusen....an Austrian village in the north of the country....just outside of Linz, and maybe an hour's drive from Passau, Germany.
It's a mountainous area that was fairly stable with a population of a thousand residents for decades....then came WW II, and from the 1950s, 1960s and 1970s....massive expansion and they have over 3,600 people today. Their footnote in history? They had a large number of technology and industrial operations for WW II, with forced labor. It's not exactly a reputation that you'd want to live with, and the locals would like to just drop the past history and focus on the future.
So, onto the nuke topic. There's been a belief for years that Hitler's war machine had gone to a stage where the nuclear weapon idea was progressing. This film producer has identified the area and done a bit of digging. There's enough bits and pieces to suggest that he might be onto something.....but oddly enough....the local police stepped in and said he didn't have the permission of the owner to dig on the property. This guy notes that he has the full permission of the owner, and there's some apparent court action expected in January to allow him to continue on with his project.
What some folks anticipate is that there's more to the story. More radioactivity reported in the area? Yeah, that's part of the mystery to the episode. There's a belief that an actual nuke explosion (minor in nature) did occur somewhere in this mountainous area, and likely proved the successful nature of the program. No report....at least issued from any of the war-time powers....has ever suggested an experiment was concluded and a nuke explosion occurred. If one is proven....it opens up a number of doors and will cause more curiosity into what was going on.
The odds of the film producer being permanently halted from digging in the area? I'd take a guess at better than fifty-fifty. It opens up old wounds and hostility over blame. No one wants to hear the rest of the story.