I have a job interview with Exelon later this month. It is for a direct hire SRO position. This is my first job interview ever. Navy and KFC are my only employment history. I don't know what to wear, dont know what to expect at all. It is a 3 day process, with testing, interview, and more interview. Do I wear a suit everyday? Should I really have three suits for this? I am sure someone here has done this interview before.
Business casual is acceptable for the first two days, however, you may be in the minority, as most of your peers will probably wear a suit. Wear a suit for the interview. It's a small thing that shows you are taking this seriously. One suit should suffice, but maybe bring a backup.
The previous posters were spot on with the behavioral based interview, STAR techniques, etc.
The only time you will be at the site is for the interview. Arrive early (30 minutes minimum) to get through security and get lost. Request to see the simulator but understand that it probably won't be possible.
Keywords and tricky phrases: safety, teamwork, follow procedures, mentor and coaching, command and control, conservatism, etc.
Unless things have changed, you won't have to do the POSS, only the BMST. Don't take my word for it though, reach out to the HR rep you've been in contact with. There is sufficient information on this site to help you pass the BMST (and POSS if required).
Your supervisory assessment can be challenging, however, remember to focus on prioritizing and those keywords and tricky phrases I mentioned above. Also, search through this site for interview information throughout the industry. Most of the nuke plant interviews have the same basic style of question, regardless of position.
Thanks for swinging by here. That alone should set you apart from your interviewing peers. I spent hours upon hours on this site prior to my interview, and now I'm in a position to mentor you. Good luck.