Well I promised updates, and I'm here to make good on those promises.
I had my first POSS experience yesterday and luckily I passed. For the most part I credit this forum for my success - I feel certain I would have been unprepared without the resources here. My test was just the POSS (no MASS) and included the "long" math section. In hopes that my experience can benefit others, I will post yet another "reflection on the POSS" separately. On one hand I hate to clutter up the forum, but on the other I know that I read every thread available at least twice looking for advice. If it is seen as unnecessary, I invite a moderator to remove it.
After my POSS (it was graded within 15 minutes) I had 3 hours to prepare for my interview. The interview was at the plant (about 45 minutes away) so I left with plenty of extra time to make the trip. This turned out to be an excellent choice as the directions provided by HR neglected to tell me how to get through the security gate, where to park, how to get to the correct building, etc. It felt wrong somehow to wander around a nuclear facility looking for a nondescript building to meet "some guy" so I called HR to figure out what to do. Unfortunately this wasn't very helpful and I did end up wandering around alone until I found the building with 3 minutes to spare. Seeing guards with machine guns made the experience surreal.
The interview itself went smoothly I believe. I was expecting more STAR-based questions and a very intense atmosphere, but it was very laid-back and amicable. Instead of a 4 or 5-member panel the interview was conducted by the hiring manager alone yielding a very personal feel. I received great information about the position, plant, staff, company, etc. as well as decent feedback for my answers throughout the interview. We went for 1 hour and 45 minutes of the scheduled 2 hours, but given it was one-on-one I felt OK with this.
The hiring manager left me with his business card and told me decisions would be made quickly - a week and a half at most. The start date for the class is only 5 weeks away and I think this utility has been conducting interviews since October for this position.
Thanks again to everyone, those who responded to my thread and PMs, and those who have posted in other interview/POSS threads. This website is an excellent resource and I only hope I can give something back to others looking for advice and information someday. For those seeking POSS or interview advice feel free to PM me - I may not have the experience of BZ or JustinHEMI, but I am willing to help as best I can.
Edit: My reflection on the POSS is here -
http://www.nukeworker.com/forum/index.php/topic,23375.0.html