I went through it in 2000 with a Civil Engineering Degree. My first interview was a physics based question with a block on a inclined plane, pretty easy. The rest of that interview was shooting the breeze. The second interview was a statistics based question. No shooting the breeze with this guy, he was all serious.
The interview with Adm Bowman was pretty lame, he just asked me what I would do with the signing bonus and then said congrats.
I would review the physics stuff, it will definitely be fair game and is probably the most common type of question these guys ask since everyone has to have done physics, regardless of major. I wouldn't think they would go to deeply into math, though you never know with Naval Reactors.
Good Luck!