Question -- I wonder if my minor quibble with the use of the word "clean" in this context is justified: If fusion reactions blast out high-energy neutrons, perhaps the MSM should be dissuaded from calling it "clean" energy? Laymen are going to get the idea that clean means "safe." In fact, I've seen some pretty wild futuristic claims about cold fusion, e.g., where everything from wrist watches, to blenders, to automobiles, to nuclear submarines would all have their own little cold fusion nuclear power plant onboard, and big centralized power plants run by big utility companies would be a thing of the past. But I think these claims neglect the spray of neutrons you'd get out such devices . . . Or am I wrong about that?
No, your BS detector is working just fine.
--Boot Hill
I always wondered about that too. The nuetrons can irradiate objects, can't they?
Of course, I imagine they're easily contained in the (hypothetical) retaining walls of a powerplant.
If you get Helium 4 out of it, you don't need shielding. If you get Helium 3 out of it, then you do.
Helium 3 is needed so that you get a self sustaining chain reaction. Helium 4 is an energy sink, probably taking more energy (to make the neutron spray, and make the bubbles) than it gets out.
Shielding would be necessary for a power source. With the power source you could synthetically generate Hydrogen gas for a nice fuel cell. The Fuel cell gets you away from Euler efficiency limits because it is a kind of battery, instead of a heat engine. That doubles your time or range (60% rather than 30% efficiency) for a fixed amount of fuel.