From the report, we are not talking about Orion, or direct thrust from nuclear heating, but rather some sort of electric propulsion system using electricity from a reactor for a proposed mission to Mars.

Something like ion drive, or plasma drive would likely cut transit time by at least ¾ for a manned trip to Mars, and if a ground base were established, a nuclear power supply would handle the reduced solar energy levels there.

I’d take this with a grain of salt, because the cost quoted for this is a bit over US $¾ billion, which sounds like a quote from Never Land.