And then what do you do with the hydrogen? Unless you plan on fueling your spaceship with it, you must burn it off to harvest the thermal energy... I'm sure you see the issue here.
Ammonia, Methanol, etc - Fertilisers and fuels for marine shipping in addition to being transportable "energy" that's less slippery than hydrogen and can travle further than an HVDC transmission line "extension cord".
Currently green hydrogen plants are expanding and ammonia | methanol marine fuel ships have been built and trialed - there are contracts signed and in the works to both build a 4,000 km HVDC "suncable" and to ship hydogen products longer distance.
You pipe it somewhere and burn it, in a heater, or an engine, or a smaller generator, the way natural gas is used today. Or fill a tank with it and power a vehicle.
However, I appreciate the point made about hydrogen escaping and causing embrittlement of materials.
You want to use thermal energy to make hydrogen, then burn that hydrogen to make thermal energy, possibly even to harvest that thermal energy to produce electricity...
The idea is that nuclear fission produces thermal energy, the production of hydrogen provides a means of storing and transporting that energy to its point of use. It might be useful to draw a diagram.
Electricity is really just another means to the same end. You can't use all of the energy generated by a power plant, at the plant site, so you transport the energy to places where it's needed.
