Not sure that nuclear propulsion will bring the stars within reach — at least as long as “we” are mortal organic beings — but it would make our solar system a-lot “smaller”. The idea is intriguing. There have been a-lot of improved models for how to do it since Icarus. Here is a recent one. And Princeton Satellite Systems has been doing very promising research on fusion propulsion, e.g., this.

Also, it turns out that if one is a little less ambitious, it is much easier to create fission propulsion: pellets of plutonium can be compressed to critical density using fairly modest electron beams, to initiate fission, which can heat inert propellant to millions of degrees. The disadvantage is that the exhaust is highly radioactive — but for shuttle vehicles that never take off or land from a planet that would not matter.