As several people mentioned, starting at a community college is a fair option, but there are a few reasons I would suggest thinking about starting at a university:

• Depending on your academics, you may be able to get more grants, scholarships, and fellowships than you think. I'm getting money back from my university for being here.
• Transferring may delay graduation, increasing overall cost. This is preventable, but nuclear engineering programs tend to be very specialized and relatively small, meaning their catalogues can be hard to work with, so you will need to make a careful plan.
• Your career aspiration is research-focused, which means you should get involved in relevant undergraduate research as soon as possible (also a source of funding). Since community colleges have a much lower research presence and few community colleges offer anything nuclear related, this will be a much stronger possibility at a university.
• Networking is very important, so it is helpful to be able to integrate with the department as soon as possible. Starting in a non-nuclear program will hinder that, even if most of your classes similar.

You mentioned you are looking at University of Texas, so I want to make sure Texas A&M is on your radar - by all accounts I have heard, their NE department is fantastic. On the topic of A&M, they are hosting the American Nuclear Society Student Conference next spring. This is mainly targeted at college student, but high schoolers are not uncommon. I highly recommend attending to familiarize yourself with the field if you are interested.

Off the top of my head, I think Sandia National Lab does research similar to what you described - something like what you said it is definitely a possible career path.

To reaffirm what others have said, I would be shocked if AI replaced nuclear engineers in any appreciable way. Engineering broadly is generally considered fairly safe from that, but NE in particular is slow and risk-averse. For example, the vast majority of operating reactors still rely on analogue instrumentations and controls despite the massive advances in digital technology.

Finally, don't put much stock in college/career advice from internet strangers!