Become a specialist, or drive funding/regulatory pushes towards these new hardware technologies. Figure out what you see as the barriers to their commercialization, then figure out what component of that problem you'd love to work on, and become an expert in that.
My biased answer:
If you're in the position to spend a lot of time learning and experimenting with new stuff (e.g. a highschool or uni student), I'd recommend becoming an expert somewhere along the liquid fueled fission reactor stack. Chem eng, nuclear eng, rare earth extraction, uranium extraction, working with molten salts, working with liquid metals, anything like that.
If all goes well, I'll be needing people in just about every specialization there.
Being a specialist isn't enough. You along - no matter how good you are - are not enough. Either you need to control enough money that you can hire many specialist (Elon Musk with SpaceX), or you need to convince someone with money that is the right path. The skills for each of these are people skills not technical. Either way you will spend all your time in management activities so technical skills are not worth learning (beyond enough to understand what is feasible).
If you want to focus on technical skills, then you need to find a specialty that someone with good management skills will think important so that you can work with many other experts to develop things.
Companies that change the physical world require a lot higher specialist:founder ratio. There is enough capital and ambitious managerial types around, what we really have a shortage of is specialists in new technical areas.
Well, there are engineers needed to develop new CAD / sim software to better model liquid nuclear fuels. That basically would require you to have a very good understanding of software engineering + fluid mechanics, nuclear physics, thermodynamics and chemistry
I love how you say you're working on fission because it's at <1% of its potential. That's a really wise perspective.
> If all goes well, I'll be needing people in just about every specialization there.
How far along are you in the Oak Ridge guys' elaborately detailed Molten Salt Reactor development program plan from 1974 [1], as far as it's relevant? If parts of it are irrelevant, how significant are the things you have to do that they didn't?
There are some things that have become irrelevant for now, particularly the need for a stellite alloy. Most of the things we are doing differently from ORNL in our division for thermal MSRs is based on the progress in materials and CAD since the winding down of the ORNL MSRs.
There are a lot of promising mostly mix-able design choices in MSRs that have become apparent in the last few decades, so we are never fully committed to a particular set.
