Reactors for naval vessels are designed to have very long lifetimes without the need to refuel. Discuss possible techniques that can be used to maintain criticality over the core lifetime as 235 U is...

Reactors for naval vessels are designed to have very long lifetimes without the need to refuel. Discuss possible techniques that can be used to maintain criticality over the core lifetime as
²³⁵U is consumed.

A nuclear rocket propulsion system uses an ion drive to accelerate mercury atoms to energies of 50 keV. Estimate the specific impulse of this drive.