It's powered by sticking a few neutrons in the combustion chamber which will then fission the DEUT. To make the DEUT a more powerful fuel, I set its life to 10000, but this also means it will take a long time to "burn up" all the fuel (hours possibly, maybe even more than a day, I haven't timed it).

Here's a slight improvement on my design.


And no, my rocket isn't based off of that other one. Your "ion rocket" doesn't fission the DEUT, it just pretends that the DUET is the exhaust of the rocket. Plus mine is realistic, with a separate fuel tank, combustion chamber, and exhaust nozzle.




Here's another improvement. This one significantly reduces the air velocity stream's tendency to bend toward the left side of the exhaust nozzle.