Nuclear vehicles widespread?

As the topic says, was it (or is it) ever possible for nuclear vehicles (not counting aircraft or ships) to be a common sight on roadways or railroads? Assuming that we truly had an "atomic era" where nuclear power was able to become the dominant power source for society.

I'll get this out of the way too, I don't mean anything like the Ford Nucleon. It is physically impossible to make a reactor that small, and even the smallest reactors would be utterly wasted in a passenger vehicle. The only possibility I've heard is that an isotope of americium can in theory produce an incredibly small (about basketball-sized IIRC) reactor. But even that I doubt would be feasible for powering a passenger vehicle, although it would be good for powering a large truck or a train.

The solution to nuclear vehicles is a radioisotope thermal generator (RTG), which is powered by the decay heat from radioisotopes. IOTL, these are used mainly on space probes and remote installations in the Arctic (lighthouses, monitering posts, etc.). These can be miniaturised and potentially used as fuel for vehicles. The advantage is that if you use the right isotope, your vehicle can go for years without refueling. And in theory, potentially you could plug your car in when it was parked to feed energy back into the grid. IIRC, there's similar concepts like a betavoltaic battery, which is powered by beta radiation. Either would work, and it's still a nuclear car.

Presumably, this would eliminate gas stations, since the car would almost never need fuel. Depending on the isotope used, an RTG could go without fueling the entire lifespan of the vehicle, although you might need to refuel it every few years. This would be done at specific facilities with trained technicians.

The best sources would appear to be plutonium-238, strontium-90, and curium-244. Pu-238 might be the best since it's half-life of 87 years means the vehicle would likely never need refueling, since noticeable power loss would not occur for decades--it also needs minimal shielding, reducing the weight of the vehicle. Sr-90 is more power dense than Pu-238, but needs more shielding and only has a half-life of 28 years--however, Sr-90 is by far the cheapest of these isotopes to produce. Cm-244 only has a half-life of 18 years and is expensive, but is more power dense (although makes up for it by needing more shielding). Spent fuel sources would be recycled in some form, probably by conversion back into nuclear fuels although Sr-90 is rather less useful.

The biggest problem is of course car accidents. Millions of car accidents occur in developed nations, and developing nations are even worse in terms of vehicle accidents per capita. A serious car accident has a high chance of spewing radioactive materials all over the roadway. This would be a Level 2 incident (IIRC) on the International Nuclear Event Scale. Disposal of old cars would become a major concern, and security could be breached. In Russia, for instance, some of their RTGs have been broken into and stolen by thieves. Events like the Goiânia accident could be common in such a society. The material in an RTG is useful for building dirty bombs, so if RTGs are everywhere, acquiring nuclear materials is thus pretty easy and dirty bombs are far easier to construct.

Cancer might be a concern, but the number of nuclear power plants needed to produce the required material would be far worse for public health. However, the common availability of radioisotopes would probably mean better (and cheaper) treatments for many forms of cancer so I'd expect the number of deaths from cancer to be lower than OTL.

This is why passenger vehicles powered on nuclear fuel would never become common before self-driving cars are universal. Only large commercial vehicles might be powered by nuclear fuel, and probably only some companies would use them. These vehicles would have better shielding and their size makes them less vulnerable to catastrophic accidents which would cause their radioactive fuel to be released. Nuclear trains would be a potential as well under current technology.

When self-driving cars are universal on the roadway (the era when driving manually on a public roadway will be just as illegal as drunk driving), I could see most cars being powered by RTG engines. The rate of car accidents will be way down, and many vehicles will likely be taken off the roadway in general as personal vehicle ownership becomes less common, further reducing the risk of accidents.

The fuel savings are pretty incredible, given that billions of gallons of fuel is no longer needed. This would have huge economic benefits at many levels, from reduced transportation costs to additional household income.

Is any of this a plausible or realistic development of 20th century technology, or perhaps more something we might see in the future? Was it ever plausible for nuclear trains or semi-trucks to be common?
 
No, Material is too rare, output is too low and inefficient and the safety hazards are so enormous that it can never be put in the hands of or even near the average consumer. The safety comparison to a nuclear reactor does not work, nuclear powerplants generally have much better safety precautions (as in they will shoot you if you break in) and are much more efficient. We have had 2-3 very serious nuclear powerplant accidents in the history of nuclear power. we have millions of car accidents every year.

To illustrate the problem: Nuclear thermoelectric/betavoltaic generators are only useful for long term output that cannot be or are difficult to replenish like space probes or remote autonomous locations like the soviet nuclear lighthouses (as well as some electronic memory devices that requires a long term extremely reliable but VERY low output powersource), It simply does not make sense to use it for anything else due to safety hazards and inefficiency. Even with this extreme niche we are still running out of the materials to build such generators.
 
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If nuclear power plants were the dominant form of energy, then I'm sure you could produce huge amounts of Sr-90 and possibly Pu-238 as well at economic costs--maybe even Cm-244 too. It isn't like supplying the United States 400 million gallons of gasoline a day doesn't come with a huge price tag, passed onto the consumer every time they pump gas (even discounting fuel taxes). I don't believe the safety hazards are insurmountable to overcome either. People use tons of dangerous chemicals regularly. Gasoline is a dangerous substance. Presumably, the public TTL is less concerned about radiation poisoning (it's just getting sick after all). Polonium-210 is a component of tobacco smoke after all, and people still smoke. It's pretty dangerous stuff, but automobile design (where you'd need specialised equipment to remove the battery), warning labels, and cautionary media reports could minimise deaths from it. Some people will no doubt die or be horribly injured from messing around with it, but people already die and are horribly injured from drinking fuel as it is.

Output might be a problem, since you would have to use quite a bit of radioactive material in the vehicle (plus shielding). Would a shorter-lived isotope be better? Po-210 gives quite a bit more energy at the cost of a half-life of only 138 days (so probably you'd need a refuel every month or two instead of years). Curium-242 is another potential for lower half-life vehicles, and also ruthenium-106 (half-life of a year). Ru-106 is relatively common in nuclear waste, and also decays to stable palladium, a precious metal.
 
Presumably, the public TTL is less concerned about radiation poisoning (it's just getting sick after all).

No, no they would not be. The amount of material required would pose an insane general security risk. radioactive isotopes grow exponentially more hazardous the more you put in one place. Its not a linear increase but rather exponential. Po-210 in cigarettes is safe due to insanely low concentrations but its actually 250000 times more lethal than cyanide and inhaling a dose of 50 nanograms is lethal. This is true for most nuclear compounds. Curium is so rare no amount of nuclear generator output could produce enough, same with ruthenium.
 
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Highly unlikely. But...
Given the development of truck mounted mini-reactors, and the development of small (immobile) reactors for us in the Arctic you might see (given better overall reactors) a nuclear powered version of the Antarctic Snow Cruiser being used for polar exploration, possible based out of Camp Century (the "nuclear powered ice city") and McMurdo (which also used a nuclear reactor for a period).
 
I'm not sure that the engineering of powering a car with an RTG is as easy as you think. A few things I know about RTGs from their spaceflight applications come into play:
(1) They are incredibly low in power-to-weight. An MMRTG like off Curiosity produces about 100W, but weight about 40 kg. A typical low-performance sedan has about 100 kW on tap--a thousand times more power!--and thus would need to be about 40 tons. A system using active energy capture like the Advanced Sterling RTG (ASRTG) can get that down to 140 W/34 kg, for a car-power-system weight of "only" 24 tons. Because with an RTG you're staying sub-critical and only harnessing sub-critical decay heat, t's not practical as a power system for a car that weighs in at maybe half a ton--even less suited than a full reactor would be. You'd need about two orders of magnitude in power-to-weight (from the state-of-the-art in spacecraft which are incredibly driven by weight) to get anywhere near a viable system.
(2) They do not throttle. Once assembled, you can predict the power output of an RTG many half-lives into the future--decades, for the plutonium RTGs favored for space. They are excellent for consistent, predictable power--the vehicle equivalent of "Base-load" generation. In contrast, a car has anything but constant power requirements. In traffic, power requirements might just be heating and cooling the cabin, for a kW or so. On a long city boulevard in nice weather, there might be long periods of net-zero required power, followed by a hill climb which requires full power. An RTG would need to be able to produce that peak required power constantly, and then waste it, unless the car also carried a battery like a hybrid/electric car...in which case why not simply use that for the main power?
 
I can imagine nuclear power being applied on a large and possibly heavily armored (hardened) vehicle meant to serve as a self-contained mobile command and control platform, like a smaller, land-based counterpart to the SSV-33. It might be useful in the event of World War III or some other major disruption to the conventional military infrastructure, or as a redundancy measure if the planners decide underground bunkers, AWACS, etc. aren't enough. We might call it a "Strategic Logistical Vehicle."
 
OTL The first nuclear-powered trains started hauling passengers and cargo 50 year’s ago!
...... around the same time that civilian nuclear generating plants started feeding electricity into public power grids.
Electric trains, cable cars, gondolas and subways are most cost effective on short, high- density routes within large cities or as connections to nearby, densely-populated cities. Electrified railways criss-cross Europe.
The type of fuel (wind, water, solar, petroleum, nuclear, etc.) is insignificant as long as it is cheap. Noisy, smelly, smoky, radioactive, carcinogenic, etc. stationary power plants can be hidden away from public eyes.
 
No, no they would not be. The amount of material required would pose an insane general security risk. radioactive isotopes grow exponentially more hazardous the more you put in one place. Its not a linear increase but rather exponential. Po-210 in cigarettes is safe due to insanely low concentrations but its actually 250000 times more lethal than cyanide and inhaling a dose of 50 nanograms is lethal. This is true for most nuclear compounds. Curium is so rare no amount of nuclear generator output could produce enough, same with ruthenium.

It's a chunk of metal which isn't likely to be vaporised even in the most deadly car accidents, since no one would be breathing it in. Not only would the engine itself have to be broken, but the large amount of shielding (lead or something similar) around it too. Anyone trying to take apart that part of the car would either use the utmost caution or pay the consequences for it, and most likely few people would ever try to do that due to the danger--you can make all sorts of deadly compounds with nothing but basic household chemicals, but few people ever actually do that.

Generally, only trained technicians would work on that part of the car (since there would be much more nuclear power, nuclear engineering would be a very common field of study). It would likely be a serious crime to buy or sell RTGs and/or the material inside without a license.

Perhaps curium might be too rare to be the sole power source, but enough reactors and processing facilities to recover the more common Ru-106 might be doable, especially since Ru-106 itself is a good source of palladium.

I'm not sure that the engineering of powering a car with an RTG is as easy as you think. A few things I know about RTGs from their spaceflight applications come into play:
(1) They are incredibly low in power-to-weight. An MMRTG like off Curiosity produces about 100W, but weight about 40 kg. A typical low-performance sedan has about 100 kW on tap--a thousand times more power!--and thus would need to be about 40 tons. A system using active energy capture like the Advanced Sterling RTG (ASRTG) can get that down to 140 W/34 kg, for a car-power-system weight of "only" 24 tons. Because with an RTG you're staying sub-critical and only harnessing sub-critical decay heat, t's not practical as a power system for a car that weighs in at maybe half a ton--even less suited than a full reactor would be. You'd need about two orders of magnitude in power-to-weight (from the state-of-the-art in spacecraft which are incredibly driven by weight) to get anywhere near a viable system.

Isn't that because the technology has never been truly invested in outside of the applications in spacecraft, remote lighthouses, etc.? Is it truly impossible to use an RTG to power a car which people could ride in?

(2) They do not throttle. Once assembled, you can predict the power output of an RTG many half-lives into the future--decades, for the plutonium RTGs favored for space. They are excellent for consistent, predictable power--the vehicle equivalent of "Base-load" generation. In contrast, a car has anything but constant power requirements. In traffic, power requirements might just be heating and cooling the cabin, for a kW or so. On a long city boulevard in nice weather, there might be long periods of net-zero required power, followed by a hill climb which requires full power. An RTG would need to be able to produce that peak required power constantly, and then waste it, unless the car also carried a battery like a hybrid/electric car...in which case why not simply use that for the main power?

Is waste really that big of an issue when the power source is far more viable than chemical fuels? There's always the idea of plugging in the vehicle when not in use to feed energy into the grid.

Nuclear power is just too expensive to be useful.

Except for the fact that it's green energy which is better than any other green energy source at the cost of a potential for accidents which are highly unlikely to be worse than coal ash or oil pipeline spills. As noted, in a scenario like this much of the nuclear waste is being recycled for energy.

OTL The first nuclear-powered trains started hauling passengers and cargo 50 year’s ago!
...... around the same time that civilian nuclear generating plants started feeding electricity into public power grids.
Electric trains, cable cars, gondolas and subways are most cost effective on short, high- density routes within large cities or as connections to nearby, densely-populated cities. Electrified railways criss-cross Europe.
The type of fuel (wind, water, solar, petroleum, nuclear, etc.) is insignificant as long as it is cheap. Noisy, smelly, smoky, radioactive, carcinogenic, etc. stationary power plants can be hidden away from public eyes.

You could consider electrified railroads in France "nuclear trains" (given the huge amount of nuclear energy in France), but technically the trains themselves aren't nuclear powered. Now if you had as widespread of nuclear power as this scenario would posit, I wonder if you'd either have nuclear locomotives in the United States (replacing diesel locomotives which are far more common) or if the cheap power would be another reason to increase railway electrification in the United States. And perhaps the same for countries without much railway electrification.
 
I'm not sure that the engineering of powering a car with an RTG is as easy as you think. A few things I know about RTGs from their spaceflight applications come into play:
(1) They are incredibly low in power-to-weight. An MMRTG like off Curiosity produces about 100W, but weight about 40 kg. A typical low-performance sedan has about 100 kW on tap--a thousand times more power!--and thus would need to be about 40 tons. A system using active energy capture like the Advanced Sterling RTG (ASRTG) can get that down to 140 W/34 kg, for a car-power-system weight of "only" 24 tons. Because with an RTG you're staying sub-critical and only harnessing sub-critical decay heat, t's not practical as a power system for a car that weighs in at maybe half a ton--even less suited than a full reactor would be. You'd need about two orders of magnitude in power-to-weight (from the state-of-the-art in spacecraft which are incredibly driven by weight) to get anywhere near a viable system.
(2) They do not throttle. Once assembled, you can predict the power output of an RTG many half-lives into the future--decades, for the plutonium RTGs favored for space. They are excellent for consistent, predictable power--the vehicle equivalent of "Base-load" generation. In contrast, a car has anything but constant power requirements. In traffic, power requirements might just be heating and cooling the cabin, for a kW or so. On a long city boulevard in nice weather, there might be long periods of net-zero required power, followed by a hill climb which requires full power. An RTG would need to be able to produce that peak required power constantly, and then waste it, unless the car also carried a battery like a hybrid/electric car...in which case why not simply use that for the main power?
I could possibly see RTG's being used as an Auxilary power source in a very few niche automotive applications. (Ie maybe a vehicle that needs to sit un attended for years / decades and needs a constant trickle charge to top up other batteries, that in turn would start an internal combustion engine.) I would expect the weight and sheilding requirements may be an issue. Perhaps the RTG would be left behind once the parent vehicle is running ?

The heat produced by an RTG may also be usefull in this type of application ?

Maybe if the military wanted to bury vehicles under ground in hidden facilities for use during or after WW3 then RTG's could play role in keeping them ready to run :)
 
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Isn't that because the technology has never been truly invested in outside of the applications in spacecraft, remote lighthouses, etc.? Is it truly impossible to use an RTG to power a car which people could ride in?
Spacecraft are very mass sensitive, so in general you'd need to look at what you're changing from one to justify the savings. Most of the weight of a space-rated RTG isn't the fuel itself, so higher-output, lower-life fuels wouldn't solve the mass problem. Being able to cool with air and convection instead of radiation alone would help a bit, and that might buy you a factor-of-ten reduction, but not the factor-of-200 you need. Using a Sterling engine or something like a turbine could help, using a carnot heat engine instead of purely thermocouple conversion (getting you into the 25-30% efficient range instead of just the 5-10% of thermocouples in a standard RTG), but that then adds all the mass overhead of the heat exchange loop, and brings you closer to a full-n reactor in terms of complexity--the only difference is that your fission rate is lower as long as you keep the individual masses sub-critical, but in exchange you get less energy to harvest. RTGs are just, by their nature, a very poor way to harvest electrical energy from nuclear fuel at anything more than a trickle.

Is waste really that big of an issue when the power source is far more viable than chemical fuels? There's always the idea of plugging in the vehicle when not in use to feed energy into the grid.
It's not so much the energy that's wasted--it's the mass. Having an RTG that somehow gets down to a ton or two and bolting it to a car to provide 150 HP at full-throttle means you're still having to haul that around when you're only doing 30 miles per hour in a solid day of city driving. Plugging them in when they're not moving at least helps make the half a megawatt of heat you're constantly dumping out whether you're at full throttle or parked in a garage less of a waste, but the total production from all billion-odd cars you'd have to replace would exceed the world's energy needs (~15 TW) by about a factor of 6. And each one of those probably has a good 200-250 kg total of heavily radioactive materials, making each and every one a potential dirty bomb on wheel dirty bomb on wheels.
 
under the Rover program the US study allot things also land vehicle with nuclear reactor like Tanks
there biggest problem was shielding and protection of driver against radiation and safety of vehicle in a crash

The only realistic land vehicle that is being big enough would be Trains locomotive and yes they study nuclear power Trains, not only in US but also in USSR.

on use of RTG in cars
the Cassini probe lifetime 20 years power needed 885 watt at begin, 663 watt at end of mission
provided by 33 kg (73 lb) of plutonium-238 (in the form of plutonium dioxide)
to compare
The TESLA base Model 3 has a 50000 Watt electrical battery vs. Cassini 700 watt RTG
 
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