RTGs for civilian/home use?

[szputnyik]

I was reading an article on RTGs, mainly that modern ones could provide several hundred Watts of power.

Do you think RTGs have a future as an "unlimited" power source for desktop computers and other semi-portable home appliances, small-scale welding machines and maybe even electric cars?

If the radiation risks are effectively dealt with, would RTGs be cleared for civilian usage?

[SargeRho]

No. They are crappy power sources and likely couldn't power even the cheapest desktop PC. They produce what, 15 watts?

[Awaras]

We are running out of the fuel needed to make them:

At the other end of the periodic table, though, it looks like we really are running out of plutonium-238 . One's first impulse is to say "Good!", because the existing stockpiles are largely the result of nuclear weapons production in years past. But it's an excellent material to power radiothermal generators , since it has a reasonable half-life (87.7 years), a high decay energy, and is an alpha emitter (thus needing less heavy shielding). Note this picture of a pellet of the oxide glowing under its own heat. There are a number of proposed deep space missions that will only launch if they can use Pu-238 that no one seems to have. Russia sold about 16 kilos to the US in the early 1990s, but just a few years ago they backed out of a deal for another 10. No one's sure - or no one's saying - if that's because they would rather hold on to it themselves, or if they don't really have that amount left any more. To give you an idea, the proposed Europa mission to Jupiter would need about 22 kilos.

There are efforts to restart Pu-238 production, but as you would imagine, this is not the work of a moment. As opposed to helium, which is sitting around in natural gas underground, you're not going to be mining any plutonium. It has to be made from neptunium-237, which you only get from spent nuclear fuel rods, and the process is expensive, no fun, and hot as blazes in every sense of the word. Even if the proposed restart gets going, it'll only produce about 1.5kg per year. So if you have any plans that involve large amounts of plutonium - and they'd better involve space exploration, dude - you should take this into account.

Not sure if they can use other, more abundant forms of nuclear fuel...

[Kryten]

RTGs have been used for civilian purposes; the soviets used them to power dozens of lighthouses and navigation beacons in remote areas. However, there have been issues with these, most notably that people have stolen them and attempted to use the material for dirty bombs at least twice. I'd say that's probably the largest issue with widespread civilian RTG use; there's a lot of overlap between the properties that make material good for RTG fuel and the properties that make materials good for radiological weapons.

[-Velocity-]

RTGs were used for civilian use, at least very small RTGs, in pacemakers.

Given the current concerns with radiological weapons, and scarcity of Pu-238, it's pretty safe to assume that large RTGs will never be cleared for civilian use, at least, not until/unless the very nature of humanity changes. Pu-238 is an alpha emitter IIRC, so I think that means it's fairly "safe" unless you breathe it in (it should just give you skin burns otherwise), but that's exactly what the chemical explosive is good for- dispersing it in the air so people breathe it in.

Edited October 8, 2013 by |Velocity|

[Tarrow]

I was reading an article on RTGs, mainly that modern ones could provide several hundred Watts of power.

Do you think RTGs have a future as an "unlimited" power source for desktop computers and other semi-portable home appliances, small-scale welding machines and maybe even electric cars?

If the radiation risks are effectively dealt with, would RTGs be cleared for civilian usage?

Several hundred watts isn't sufficient to run an electric vehicle sadly. Even something as lowly as the electric side of a petrol / electric hybrid is up in the dozens of kilowatts, with some pure electric vehicles up in the hundreds of kilowatts. There's also the issue of giving every idiot on the planet access to radiological materials.

Hydrogen fuel cells / hydrogen combustion engines are a much better bet. Zero recharge time (just a tank refill), fuel is made from water and unlike RTG's they'll maintain their full power output for as long as fuel is available. Ironically the tech exists to do this right now but environmentalists object strongly to the precursor work required for emissions-free power generation.

[architeuthis]

I think in the gleaming future envisioned in the 1950's small modular nuclear reactors or little slugs of Plutonium would power everything, even consumer electronics. In reality the typical American household draws roughly 1000 W of power, and we don't have heaps of Pu238 Sr90 or Am241 lying around for handy use, making RTGs simply too impractical for everyday use by civilians.

[Winter Man]

There was talk a little while back of a small town scale generator that'd get buried under a public building, encased in concrete. It'd have worked pretty much squarely in between a conventional reactor and an RTG, using a core with no moving parts but with a steam generator instead of a thermoelectric one, getting round the inefficiency.

[Awaras]

There was talk a little while back of a small town scale generator that'd get buried under a public building, encased in concrete. It'd have worked pretty much squarely in between a conventional reactor and an RTG, using a core with no moving parts but with a steam generator instead of a thermoelectric one, getting round the inefficiency.

I remember reading about this a while back. Wasn't Bill Gates involved with it in some way?

[lajoswinkler]

Voyagers, Pioneer, Cassini, all that belongs to civilian projects. Almost all space probes and exploration that used RTGs are civilian and I'm saying "almost all" because I don't know about the military ones.

Citizen home use? God I hope not. I don't even think it needs to be explained why. It's obvious.

[drakesdoom]

Hydrogen fuel cells / hydrogen combustion engines are a much better bet. Zero recharge time (just a tank refill), fuel is made from water and unlike RTG's they'll maintain their full power output for as long as fuel is available. Ironically the tech exists to do this right now but environmentalists object strongly to the precursor work required for emissions-free power generation.

The problem with hydrogen fuel cells is it is only a way to store and transport power, you still have to run conventional generators to split off the hydrogen in the first place.

[Scotius]

Have you ever played Fallout 3? All these derelict cars rusting everywhere, each with its own small nuclear power source...Best tactic to deal with enemies? Put couple of bullets into nearest wreck, take cover and watch how small, neat mushroom of death turns them to ash Fun in game, but you DON'T want to have lumps of fissionable materials all around you.

[magnemoe]

There was talk a little while back of a small town scale generator that'd get buried under a public building, encased in concrete. It'd have worked pretty much squarely in between a conventional reactor and an RTG, using a core with no moving parts but with a steam generator instead of a thermoelectric one, getting round the inefficiency.

It pretty much had to have moving parts, at least outside, as you needed to connect it to an steam turbine. This is probably something like the small reactors used in submarines.

As they are small they contain lite heat so they will fail safe even if cooling water is cut.

Large reactors has the problem that if they loose cooling they contain so much heat they will damage themselves even then shut down if they lose cooling.

Upside is that you only need a few to power an country.

[drakesdoom]

Have you ever played Fallout 3? All these derelict cars rusting everywhere, each with its own small nuclear power source...Best tactic to deal with enemies? Put couple of bullets into nearest wreck, take cover and watch how small, neat mushroom of death turns them to ash Fun in game, but you DON'T want to have lumps of fissionable materials all around you.

That was a game, real rtgs in a worst case scenario are hot temperature wise and a minor radiation risk for 80 some years and are then a heap of odd rock.

[lajoswinkler]

That was a game, real rtgs in a worst case scenario are hot temperature wise and a minor radiation risk for 80 some years and are then a heap of odd rock.

:huh:

This is exactly what I'm talking about. This is why RTGs must never come into the hands of regular Joe.

[Vaebn]

The real reason is because of the fear that someone will turn it into dust and spread it all over the place.

Plutonium would actually be really safe, if people weren't assumed to be dicks. It's alpha radiation can be stopped by wrapping it in newspaper or something.

However "easily stopped" in terms of radiation is just another way of saying "the subject next to it, absorbs the entirety of it". This is not a problem if it is newspaper, this is a problem if it is cells.

Much like a toxic heavy metal, it also has a tendency to accumulate in the bones and liver. At which point, you have a sort of dust that irradiates what is right next to it.

[automcdonough]

yes the plutonium is a difficult fuel to get.

From the wiki:

238Pu, 90Sr

Plutonium-238 has the lowest shielding requirements and longest half-life; its power output is 0.54 kilowatts per kilogram. Only three candidate isotopes meet the last criterion (not all are listed above) and need less than 25 mm of lead shielding to block the radiation. 238Pu (the best of these three) needs less than 2.5 mm, and in many cases no shielding is needed in a 238Pu RTG, as the casing itself is adequate. 238Pu has become the most widely used fuel for RTGs, in the form of plutonium(IV) oxide (PuO2). 238Pu has a half-life of 87.7 years, reasonable power density, and exceptionally low gamma and neutron radiation levels.

Strontium-90 also requires little shielding, as it decays by β emission, with negligible γ emission. While its half life of 28.8 years is much shorter than that of 238Pu, it also has a much lower decay energy. Thus its power density is only 0.46 kilowatts per kilogram. Because the energy output is lower it reaches lower temperatures than 238Pu, which results in lower RTG efficiency. 90Sr is a high yield waste product of nuclear fission and is available in large quantities at a low price.[11]

So the 2nd place fuel, Strontium has a shorter half life (which is still very useful to us, not being stuck in space), and it's a cheap common waste byproduct.

RTG's powered by Strontium COULD be really common and there are probably a lot of applications where it would be handy. HOWEVER.. and RTG is terribly inefficient from a size, weight, and cost perspective. It's only selling points are that it produces usable pwer for a few decades and that it's extremely reliable with no moving parts.

For things like remote communications, warning lights, etc.. it's great. laptop? forget it.

One that produces 40W of juice weighs 20kg (44lbs) and 525W of waste heat.

The one on Voyager makes 300W could swing running a computer. You'll have 4,400W of heat cooking off. That's like 4 space heaters. And it weighs 58kg (127lbs).

While it's entirely possible that since dissipating heat in an atmosphere is much easier than space should equate to a cheaper and smaller unit, don't expect anything drastic.

Much like in the game, solar and batteries make more sense for most situations.

[Seret]

The problem with hydrogen fuel cells is it is only a way to store and transport power, you still have to run conventional generators to split off the hydrogen in the first place.

Sure, all fuels are just an energy carrier. At least with hydrogen you have the option of using renewable energy. RTGs are essentially a fossil fuel.

If you want a home power source that gives you heat and electricity then you're looking at something like a fuel cell (still a bit pricey) or a microCHP. The latter can be powered by natural gas (they're just a Stirling engine driving a genny) which is pretty clean-burning. Distributing electricity production down to individual homes does have some advantages where the machine doing the generation is clean. For example you avoid transmission losses, which can be anywhere from about 5-20% depending on where you are. People also tend to be more careful about their consumption once they start microgenerating.

[nuclearpower13]

I do think that with extensive research RTG's could provide power for civilian use. They have a really good long term energy efficiency rate and a decent sized one. Like the one used on the New Horizons probe can provide at least 200 w of power. But there are a few problems. Even if they find a way to prevent radiation from escaping the RTG there is the problem of commercialization and mass production. Right now the most common fuel right now used for RTG's is Plutonium 210 which is not only really radioactive but also it is insanely expensive. For 1 gram of pure Plutonium 210 it would cost you $2800. So either they need to increase the production and extraction of Plutonium from spent nuclear reactor fuel to bring down price or they need to find a cheaper element that can maintain the same level of radioactivity. Than there is the problem of commercialization. Right now the Dept. of Energy controls the production (Which ended when the cold war ended. So now there relying on a reserve to power the RTG's) and distribution of Plutonium and the casing that produces the power.

Link to the price of plutonium below:

http://fti.neep.wisc.edu/neep602/SPRING00/lecture5.pdf

NASA is running of out Plutonium:

www.planetar.yorg/blogs/casey-dreier/2013/20130920-pu-238-is-crucial-for-space-exploration-and-we-are-almost-out.html

[Kerbin Dallas Multipass]

You may want to google the Cadillac World Thorium Fuel (WTF) Concept Car.

[magnemoe]

Have you ever played Fallout 3? All these derelict cars rusting everywhere, each with its own small nuclear power source...Best tactic to deal with enemies? Put couple of bullets into nearest wreck, take cover and watch how small, neat mushroom of death turns them to ash Fun in game, but you DON'T want to have lumps of fissionable materials all around you.

Fallout 3 was fun, kind of combining the 1950 idea of nuclear cars with the classical Hollywood exploding ones.

And yes it was the most destructive thing in the game except of the scripted nuclear bomb.

Did an badass scene where I shot up cars while walking between them who impressed an friend a lot. Fallout New Vegas has far fewer exploding cars

And no its not only an game but an in game joke. To best illustrate how explosives work in Fallout 3, you could make an hand grenade of an radioactive coca cola variant, yes it had an mushroom cloud an fallout. You also had an portable mini nuke launcher. Downside was it short range.

[Wahgineer]

I can at least think of one civilian use for RTGs:

http://en.wikipedia.org/wiki/DeLorean_time_machine

Time travel!

[p3asant]

I read somewhere there were proposed plans for small scale Thorium based reactor.

Ah, here.

Would be nice having these operating every here and there.

[automcdonough]

Reactors and RTG's, not the same thing. lol.

[lajoswinkler]

I see that even here, some people don't know the difference between ionizing radiation hazard and radiological contamination.

Ionizing radiation is rays of particles. Few metres of concrete with steel rebar and lead plates protects from gamma, neutron, alpha and beta radiation. If you have only alpha rays, a plastic bottle will keep everything inside. Hard beta rays will be blocked by thicker glass, though if put inside a metal container, will turn beta into x-rays so it's best to go with nonmetallic containers except if you use lead which absorbs x-rays easily.

Radiological contamination is dispersal of material that emits ionizing rays. It's chemical contamination and that's why you can't handle plutonium or its compounds (oxide is used in RTGs) just by using a piece of paper or a plastic bottle without problems, no matter if it shields from almost all of its rays.

Handling such compounds outside special laboratory units will result in the creation of contaminated surfaces and equipment and before you know it, it's on your sticky hands and then it's a matter of time before it can be detected in your bones, radiating your bone marrow, and you don't need a lot to start an illness.

RTGs are sealed. Nothing gets out except some gamma rays. However if you release such units into the general population, it's a matter of days before someone opens the seal and then you've got a huge problem. It would be inevitable.

Ever since mercury found its way into commercial products, its levels in the environment started growing and it has been linked to various diseases, mostly problems with embryonic development. Now imagine if all of the sudden we start detecting plutonium in our ground water. Cancer rates would skyrocket as well as spontaneous abortions and lots of really deformed and sick babies would be born.

That's why it will never find its way into the world of commercial application, even if non-fissile isotopes are used.