I've never been interested in fusion because I knew it wouldn't be viable for at least 50 years. Why bother worrying or hyping about it when it's crap? Well, I just did a spot of research into it and what I've found is simply amazing.
The main line of research is crap because the fuel they need to use (tritium) would cost millions per kilogram. This compares extremely poorly to uranium which can be had for less than 100$ per kg. Even extracting uranium from seawater costs less than 1000$ per kilogram.
Note that there isn't much conversion needed since all proposed fusion processes produce energy per kilogram of fuel at rates roughly equivalent to fission of uranium.
Let's not forget the fact that D-T fusion produces 30 times (*) the amount of neutron radiation per kilogram as uranium fission. Neutron radiation is the kind that causes things to become radioactive. I hope you love nuclear waste because D-T fusion makes fission look waste-free.
The yo-yos who want to go to the moon to mine Helium-3 say crap like "that 25-tonne load of He3 would worth on the order of $75 billion today, or $3 billion per tonne". Of course, this is a blatant lie. Helium-3 isn't worth $3 billion per tonne, it costs $3 billion per tonne. What it's actually worth if you're using it as fuel in a fusion power plant is less than $50,000 per tonne, or 60,000 times less than they're claiming.
This doesn't mean that helium-3 mining can't happen economically. It just can't happen with chemical rockets. You need nuclear (fission) rockets to get to the moon and mine that helium-3 economically. And I'm really assuming here that it'll be economical, but if you're going to be using nuclear fission rockets, if nuclear fission has gained that much political and social respectability, then why bother with a fusion reactor at all?
Why harness the power of a twinkling little star when you can harness the power of a supernova? That's where all Uranium comes from, from the r-process running up the neutron drip line, from the blazing heart of an exploding stellar super-giant. The hype around fusion defies comprehension even as mindless sun worship. Don't people realize our sun is nothing, nothing, compared to something that outshines a galaxy. It's like wishing to cuddle up to a candle when you have a roaring bonfire next to you.
But that's not where the fun ends with fusion research. You see, there's an "alternative" line of research which advertises being able to use everyday normal crap like Borax (boron) and that its reactors will be so cheap they could be built in someone's garage ....
Well problem is they can only do that if the fuel is totally pure. Boron must be purified from 80% to >99.7%, otherwise those dippy little reactors built in people's garages will kill everybody near them. The best part is that even though Borax costs $2 per kilo, pure boron costs around $5000-10,000 per kilogram depending on its purity. And you want to use that for fuel? Yeah, that's not going to happen. Don't expect any economies of scale either since industry is already making the stuff in massive quantities.
But the fun doesn't end there. You see, pure boron in fusion reactors wouldn't cut it. No siree, you need pure boron-11. Because if you shoved any boron-10 (which is 20% of natural boron) into your garage-built fusion reactor, it would ... kill everyone around it. What you really want is pure boron-11 and as it happens we do have plenty of boron-11 around since boron-10 is used as a neutron radiation absorbent by ... the nuclear fission industry.
So you see, it's beautiful. It really is. If you try to build fusion reactors to replace fission reactors then those fusion reactors won't have any fuel. The only way we'd ever have little fusion reactors in people's garages is if we have giant fission plants in every city.
*: deuterium (2 nucleons) + tritium (3 nucleons) -> helium-4 (4 nucleons) + 1 neutron for 20% of mass. In comparison, uranium (235 nucleons) + neutron -> a smorgasbord of stuff + 2.5 neutrons on average, for a net production of 1.5 neutrons (0.6% of mass) on average.