The Elephant in the Room

Actually the Soviets reported a net positive energy output from one of the last of their Tokamak test devices in the 1980s. A seldom mentioned problem they found was that the magnetic field does little to contain the prodigious neutron flux created by the plasma which has the annoying habit of causing everything nearby to glow in the dark for a very long time as well as rapidly degrading the structural integrity of the reactor components, not a very desirable thing at all. This would seem to be the greatest obstacle to practical fusion power generation. Thus, fusion reactors are not so "clean" as their proponents frequently state. Even if one were to find some way of containing the neutron flux, what does one do with a few tons of waste neutrons?

Also, just to pick a nit, the majority of the yield of most thermonuclear weapons comes from fission of the depleted uranium "tamper" used to compress the thermonuclear fuel. This is also responsible for most of the radioactive fallout. The highly energetic neutrons from the thermonuclear reaction are capable of fissioning depleted uranium and this is used to dramatically boost the yield of the device.