"We want it to be better than the early US rovers"
It's like comparing a Ferrari (Apollo rover) to a JCB (Chinese rover). The Apollo rover didn't dig but went a lot faster so the Astronauts could dig further away.
China is planning to send a nuclear powered rover to the moon in 2012 on its first unmanned mission to our natural satellite. Several technology institutes across the country are competing to develop the vehicle, although there is no word on when the official selection will be made. In what seems to be a bid to get the edge on …
There's a real benefit to radioisotope generators on lunar missions - they help keep the probe warm during the long (2 week) lunar nights when temperatures fall to about -170C.
The two Soviet Lunokhod rovers trundled around the Moon through a series of lunar days - 11 for Lunokhod 1, 5 for Lunokhod 2 - and they needed to be kept warm if there was any hope of waking them up come the lunar dawn.
During the day, the rovers were charged by solar panels, but as night fell, they'd close up their lids and rely on a chunk of polonium 210 - to keep the internal electronics snug and warm*.
Just to brighten up everyone's day; in 1969, the first attempt to launch a Lunokhod exploded 40 seconds after launch in a polonium-laced fireball.
* The effect of polonium 210 on dissident KGB officers is somewhat different.
To anyone scared: There's a difference between sending up a nuclear-powered rocket and sending up an inert nuclear reactor. The rover's reactor wouldn't actually be eating fuel and spewing power until (I presume) it lands on the moon, so there's no particular danger if the rocket blows up on the way through the atmosphere, other than dust from the fuel. It wouldn't explode like a nuclear bomb.
The only reason that I can tell why it hasn't been considered for the shuttle is that a returnable craft is inherently more dangerous if it's using a live reactor on it's way through the atmosphere, either way.
Space vehicles that use nuclear power don't use reactors in the conventional sense that eveyone is generally familiar with. There is no boiler, turbines and generator coil or any othe moving parts.
The thing is pretty much a battery and is always running so there is no on/off switch per se. The basic design is a central core of some radionucleotide in the shape of a rod surrounded by a material to slow down the particles released by the radionucleotides natural decay. Within this matrix are alternating conductive plates, either as radiating outwards in a starburst pattern or a series of closely packed disks. These become the poles of your nuclear powered battery. More along the lines of a nuclear charged capacitor than a storage battery but you get my drift.
Since the format is pretty much a cannister, it can be reasonably hardened against catastrophe .... unfortunatelly such hardening costs weight/payload ... which is at a premium and cost $$$ ... guess which wins out?
"China is planning to send a nuclear powered rover to the moon in 2012 on its first unmanned mission to our natural satellite."
So ... everyone can then relax a bit and forget those
complicated issues of global warming then, since this
bunch of morons will have, by then, rendered the whole
atmostphere brighter than it ever was at night, and
warmer than anything from current predictions .
And if we are lucky, they might even screw the Moon, so
remains only Mars to inhabitate !
Nicholas Wright, you might want to look up at the other comments for a bit and find that this was already explained. No matter what happens, that nuclear powerplant on the rover cannot explode. Similarly, since it is a solid piece of material, it can't leak and even if it did, the radiation released that way would be utterly unnoticeable compared to background radiation.
As for the issue of it explode on launch, it's not good, but compared to even a single nuclear test, it's hardly measurable. We could detonate hundreds of rovers on their way up the atmosphere and there still wouldn't be any problem. The only issue is for those directly in the rover's path while it is still at low altitudes, especially if it uses polonium or a similar extremely dangerous material.