It could depending on the type of reactor. Many Soviet reactor designs were liquid graphite cooled and put off a plutonium residue that could easily be made weapons grade. That is one of the biggest fears of countries acquiring reactor designs from the former Soviet Union.
Did you ever figure out the answer to this? This game will certainly take ages to master. For an example, I have had this game for almost a year and I only just figured out you can tell your air units and sea units to patrol for more then one month, I thought it was a set amount of time. The things you learn. lol
from what i infer in the manual, each separate reactor lvl 6 or higher in different provinces each start and end their own bomb. So start one bomb in NY, finish in, lets say, Nov. Start another one month later at the reactor in Los Alamos, finishes, in Dec. They do not affect each other at all. I am not sure, I never have the IC and time to pull off two separate lvl 6 reactors