Nuclear Car

[Ted C]

According to the article, they think they'll have a working engine in two years.

http://www.laserpowersystems.com/links/thorium-car

For those with relevant skill sets, does that sound plausible? Or is this destined to go the way of the M400 Skycar?

[Borgholio]

Ok...I get that Thorium is less radioactive and far more stable than Uranium...but it is still radioactive and still a heavy metal. I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

[Mr Bean]

Ok...I get that Thorium is less radioactive and far more stable than Uranium...but it is still radioactive and still a heavy metal. I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

And it makes less sense then building a mess of Nuclear power plants and just using hydrogen as your fuel source.

[Borgholio]

Or electric cars for that matter. Nuke plants can power millions of charging stations.

[Sky Captain]

How it is supposed to work? Heating a piece of thorium with laser to somehow trigger a fission? All proposals for subcritical thorium reactors call for massive particle accelerators to generate enough particles to trigger fission on large scale. Yet that site claim they will be able to trigger fission with laser in package compact enough to put in a car.
The whole proposal sounds like a scam. If they would be serious they would go about building a prototype to test viability of concept instead of making tons claims that sound too good to be true.

[Borgholio]

I know with Uranium and Plutonium you can use the heat released from spontaneous fission...that's what they use in deep-space probes. But I don't think Thorium gets really all that hot...

[Jaepheth]

I'd only be interested if this is the end result:



Seriously though, I'd rather see this technology powering individual homes. And from there charging electric or flywheel powered cars.

[Ted C]

Ok...I get that Thorium is less radioactive and far more stable than Uranium...but it is still radioactive and still a heavy metal. I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

According to the article, a car would only have about 8 grams of fuel in it, so we're not talking about large amounts of radioactive material in a given collision. I presume that keeping that fuel from escaping containment in an accident is included in the design.

How it is supposed to work? Heating a piece of thorium with laser to somehow trigger a fission?

According to the article, the thorium somehow powers a laser that vaporizes water to spin a turbine to generate electricity. I'm guessing some kind of dry power system like what's used on satellites to feed the laser, but the article isn't that specific.

[Ted C]

The whole proposal sounds like a scam.

Basically what I'm wondering.

[Scottish Ninja]

Ok...I get that Thorium is less radioactive and far more stable than Uranium...but it is still radioactive and still a heavy metal. I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

According to the article, a car would only have about 8 grams of fuel in it, so we're not talking about large amounts of radioactive material in a given collision. I presume that keeping that fuel from escaping containment in an accident is included in the design.

The article also mentioned the powerplant being enclosed in a 3in thick steel case - that should provide pretty substantial protection by itself.

According to the article, the thorium somehow powers a laser that vaporizes water to spin a turbine to generate electricity. I'm guessing some kind of dry power system like what's used on satellites to feed the laser, but the article isn't that specific.

I would doubt that - no way an RTG of that size is going to produce the 250 kW claimed (unless I'm really wrong about that).

[Simon_Jester]

Yeah, I'm suspicious. If it DID work...

Ok...I get that Thorium is less radioactive and far more stable than Uranium...but it is still radioactive and still a heavy metal. I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

According to the article, a car would only have about 8 grams of fuel in it, so we're not talking about large amounts of radioactive material in a given collision. I presume that keeping that fuel from escaping containment in an accident is included in the design.

A small amount of fissile or semi-fissile material is a much bigger deal than an equal amount of other radioisotopes, in some ways.* And frankly, eight grams of some radioisotopes is not a small sample.

*In other ways, less so.

One also wonders how many of these things you'd have to core to make a functional dirty bomb. Probably about a thousand, which is difficult but very far from impossible if these things ever hit mass market.

[Terralthra]

At first blush, I thought this sounded a bit fishy. 250kW from 8g of material? So I showed it to my dad, a MechEng who spent decades of his life managing nuclear reactor safety and nuclear waste safety.

After he stopped laughing...

First of all thorium by itself isn't fissile. It's bred by neutrons in U233, which is then fissioned. So, really, what they're proposing here is a pocket-sized breeder reactor. But the neutrons aren't free. You either have to get fast neutrons from an ongoing reaction, or heat the thorium (significantly) to kickstart the reaction with thermal neutrons. No one has ever proposed, to his knowledge, a nuclear breeder reactor small enough to put in a car, and if someone did build one, it'd be heavy as shit. Three inches of steel around the whole thing will do that. Even assuming the design could work, 8g of thorium bred to U233 would have at most 83 MJ of energy (that's actually U235, but U233 is comparable if slightly less), assuming perfect conversion of the thorium. Assuming further a 100% perfect laser -> turbine energy conversion, at 250 kW, that translates to...90 hours of power. Refuelling will be a cast-iron (literally) bitch. Say you have a half-hour commute each way, that means your nuclear-powered car runs for 18 weeks, at which point you have to essentially buy a new engine.

I'll pass.

Edited for mixing up kJ and MJ.

[Korto]

Even ignoring Terralthra (which I'm not), I'm quite skeptical because, if it worked as wonderfully as he says, why the fuck isn't the military breaking down his door to put it in their tanks? That would seem a much more sensible use; and powering facilities such as hospitals, factories, and so on. You know, instead of trying to convince the general public, and the politicians who depend upon their votes, that nuclear cars = safe.

[Ted C]

I asked a NASA friend about designing a nuclear car once. He said it was possible, if you didn't mind having a 3000-degree heat source in your trunk.

So, it looks like this is another M400 Skycar: lots of optimistic talk, not much realistic science.

[Sky Captain]

Even ignoring Terralthra (which I'm not), I'm quite skeptical because, if it worked as wonderfully as he says, why the fuck isn't the military breaking down his door to put it in their tanks? That would seem a much more sensible use; and powering facilities such as hospitals, factories, and so on. You know, instead of trying to convince the general public, and the politicians who depend upon their votes, that nuclear cars = safe.

Exactly, if the concept would be workable they would at first aim to build a prototype and then develop small reactors to power remote industrial sites, military bases, ships - stuff that don't care that much about the size of a power plant and high power to weight ratios and where only trained people would be allowed to run the reactor. Cars would be one of the last places where anyone serious about developing a new type of nuclear reactor would want to put their reactors. Even if there would be no technical issues an accident with radioactive leak would be very bad PR event.

[Magis]

The article is complete fucking nonsense and should be utterly ignored.

[Enigma]

Having a nuclear car isn't going to go anywhere even if they managed to build one. People already go nuts over nuclear power plants and someone thought it was a good a idea to have millions of smaller ones on the roads?

The first thought I had when this thread came up was "Oh crap, the Chinese are going to nuke us all.".

[Grumman]

One also wonders how many of these things you'd have to core to make a functional dirty bomb. Probably about a thousand, which is difficult but very far from impossible if these things ever hit mass market.

Define "functional". For a dirty bomb just one might do it, if there are enough Chicken Littles around to demand a massive and costly overreaction.

[aussiemuscle308]

I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

How much worse than big tanks filled with explosive liquids?

[krakonfour]

I can't imagine what a multi-car pileup would look like if you throw radioactive metals into the mix...

How much worse than big tanks filled with explosive liquids?

With one, you pull out the fire extinguishers and sent the cars to scrap.
With the other, you need you ensure a 10km perimeter of you're-not-allowed-to-live-here, send off the cars to decontamination and nuclear waste disposal, then have the site under radioactive inspection for a few decades.

Yeah, that's how silly the nuclear accident regulations are.

[Borgholio]

How much worse than big tanks filled with explosive liquids?

Cars don't explode that often, that's a Hollywood thing. They can certainly catch on fire if the tank is punctured but like K said, you can just put it out with a fire extinguisher. If you get a release of radioactive materials, you're just fucked.

[Sky Captain]

Currently only way how to make a nuclear car would be to make it RTG powered like Mars rover Curiosity. Howewer RTG have poor power to weight ratio so your car probably would not go any faster than bicycle. I think smallest vehicle ever seriously proposed powered by true nuclear reactor not RTG is a train locomotive and that is something like 150 - 200 ton mass. Nuclear reactors just don't scale down to a tiny car size.

[Borgholio]

http://en.wikipedia.org/wiki/Radioisoto ... _generator

Based on the chart, terrestrial models of RTGs have a horrible power to weight ratio and would not be very useful in land vehicles. The space models seem to be far more efficient but I'd wager they would not be sturdy enough for day to day use in a vehicle.

Not to mention that the space vehicles use Plutonium or Uranium instead of "safer" materials.

[Zaune]

How much worse than big tanks filled with explosive liquids?

Petrol doesn't create anywhere as serious a hazmat issue, for a start. Although on the other hand, some of the chemical byproducts you can get from setting a car on fire make plutonium-238 look mild by comparison; there are plastics out there that'll produce hydrofluoric acid if you burn them.

[Sea Skimmer]

Currently only way how to make a nuclear car would be to make it RTG powered like Mars rover Curiosity. Howewer RTG have poor power to weight ratio so your car probably would not go any faster than bicycle. I think smallest vehicle ever seriously proposed powered by true nuclear reactor not RTG is a train locomotive and that is something like 150 - 200 ton mass. Nuclear reactors just don't scale down to a tiny car size.

With a Sterling engine based RTG you can get quadruple the power of a completely passive RTG, that might make bicycle speeds on flat ground happen. On the other hand the fuel can autoignite if the cooling system breaks or gets clogged. Plutonium-238 fires would not be very healthy.