Sorry no it's not. There are basically two approaches to building a bomb. We took one route which took a longer time to develop but produced a higher yield weapon. The approach the Germans took would have produced a lower yield much "dirtier" weapon but nonetheless would have worked. They had a working reactor before the war even started. Their approach needed a large amount of heavy water. Their only plants were in Norway and the OSS launched 9 seperate missions to sabotage their efforts.
Here is the story of the most successful attempt to destroy the heavy Water Plants.
http://www.amazon.co.uk/exec/obidos/ASIN/0340830158/ref=ase_janeriks/202-6549898-8519046A letter Albert Einstien wrote to FDR warning of the German Atomic weapons research.
http://www.atomicarchive.com/Docs/Einstein.shtmlOne year before the war started the Germans had produced a fission reaction.
http://www.cccoe.k12.ca.us/abomb/timeline.htmIn the begining of the war they were farther along than the Allies.
http://www.cccoe.k12.ca.us/abomb/race.htmFACT:
December 19, 1938
Otto Hahn, Fritz Strassman and Lise Meitner produce Uranium nuclear fission at Germany's Kaiser Wilhelm Institute.
Bohr, who was insturmental in the US bomb program was good friends with Heisenberg who ended up heading up the Nazi program. There is quite a bit of speculation that Heisenberg delibrately sabotaged the German program. This is well documented in the "Farm reports" debriefing the scientist's in the program. One thing is for sure, they started the war ahead but by the end took a wrong term and would never have produced a bomb with the path they were on.
The program was far from fiction. It was a huge threat in 1940 that thru the efforts of some very brave men became a mere shadow of it's begining potential.
Crumpp