In my panic to figure out what was going on, with usscouts.org site down, and National not able to answer many questions, I started this thread. I believe that I might have worried a few that are attending the Hornaday Weekend in our area.
Here is the storey on Nuclear Science. It is the same merit badge number as the Atomic Energy Merit badge. The book as a "A" added to the end of the number, which means that it was just a scheduled update instead of a replacement. There is a name change and there is a new look to the badge. People that have already earned the Atomic Energy Merit Badge cannot earn Nuclear Science as well since it is the same badge.
People that already have a partial on Atomic Energy fall under the same regs. as any other person that has a partial when the requirements change.
The situation was just confused by the fact that they came out with the new "revised" requirements, a new name, and a new look for the badge all at the same time...