EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: jonovid on January 14, 2020, 07:44:12 am
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I came across this video by Galen Winsor, & so are wondering how much of this knowledge is suppressed by the nuclear industry & military interests.
if what Galen Winsor is saying, is somehow true, see video, if you know your nuclear science!
if radioisotope thermoelectric powered electric vehicle, or atomic cars that never need gas, for the life of the vehicle.
in theory, a suitcase sized mini radioisotope thermoelectric battery will hypothetically power an electric vehicle for 15 to 20 years
or the life of vehicle. that never needs charging. vehicle powered by plutonium.
https://www.youtube.com/watch?v=8VvGw1tkT1Q (https://www.youtube.com/watch?v=8VvGw1tkT1Q)
Galen Winsor led a full life, dying at age 82 of old age diseases.
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I just had this discussion on a different forum.
I don't think humanity would like plutionium powered cars ;)
But if you look at RTG's then you see they are extremely expensive and have relatively very little power.
NASA uses the below RTG for example, 2,7kg and 215W for 11 years, you would need ten of those for your EV and still have not enough power, the RTG's will cost a multiple of the car itself.
Then there are also Po210 cells, halftime of a half year so unusable for an EV and extremely rare and poisonous (remember the ex KGB spy who was killed in his tea)
Also consider how much energy it costs to enrich the nuclear fuel.
Yes Back To the future is a nice movie, but we have to wait till Mr Fusion arrives ;)
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It would certainly be suppressed by the nuclear industry and military if it worked.
Putting large quantities of radioactive materials in the hands of general population would be a whole new level of fun that hasn't really been seen before :D
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Also consider how much energy it costs to enrich the nuclear fuel.
That's an issue for Uranium but you can separate Pu from the waste stream chemically, which is MUCH easier.
Idea however is still a non starter for all the obvious reasons.
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Before this thread goes very far it seems very important to clear something up...
RTGs (in the US anyway) use plutonium-238. It is a strong alpha emitter, and not much else. It is not fissile, or at least not predominantly so, not by a long shot.
Plutonium-239 is the fissile isotope used in bombs.
Plutonium-244 is the more common isotope, used incidentally in commercial reactors. It is more reactive, but as far as I know, can still be crafted into bombs.
Other (lighter) isotopes have been used in RTGs before, like strontium-90, famous for being a dominant environmental component of radioactive fallout, from bomb explosions and core meltdowns.
Alpha emitters are preferred, because alphas are easily stopped. Sr90 is a beta and x-ray emitter, making it far more dangerous; more shielding is required. The Soviets used a few of these in remote locations; I don't think many were flown in space. (They did once or twice fly a rather more interesting assembly though.)
Tim
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The plutonium in TRGs is Pu238 and this is really expensive stuff. To get it in good purity it needs to be specially made in a reactor. Usually the route from Np-237 from normal reactor waste that is chemical separated and than irradiated in a special reactor to make PU-238. So this needs 2 cycles in the reactor and 2 steps of chemical separation.
Currently not even NASA has a good source for this. The power is usually low (more like < 1 kW) and the RTGs naturally run 24/7. If such a source is in a truck, expect a big warning sign at the back and maybe a police escort.
So not at all the right power source for a car.
So an RTGs is something for a deep space probe or maybe a weather station in the arctic where solar cells don't work well.
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Actually, it had even been considered for medical devices (such as pacemakers) at some point during that time... (tiny generators would last more than a lifetime).
Military interests aside, not using nuclear power directly for general-purpose applications is mostly a question of overall safety (oh, and obviously, recycling issues).
Even if we could devise small generators that are very safe, it would still be kind of breaking the hard wall of getting access to nuclear energy, which would likely pose many, many problems.
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So, I don't see a transcript and it doesn't seem worthwhile to sit through the better part of an hour of this, so I will assume that RTGs of the sort NASA is fond of, is among the proposals.
This is a thermoelectric generator, i.e. a Peltier stack, powered by Pu238 or other short-lived isotopes, which decay so quickly they give out real power. (A typical PuO2 pellet glows red hot in still air.)
The decay is constant, uncontrolled, and decreases exponentially over its lifetime, following the decay process.
Clearly, we cannot draw large power surges from these devices, nor can we completely enclose them lest they overheat. To use them in an electric vehicle, they need to stick out the back, and be large enough that the outer casing is touch safe. Conventional forced-air or water-cooled mechanisms are not nearly reliable enough here.
To accelerate a vehicle, we must have an onboard storage system. It needs to accumulate energy from the RTG -- which might be low power, 1kW nominal say -- over many hours, to deliver a practical 10, 50, 200kW, whatever, on demand. A battery is required. (Modern lithium ion would be quite practical, but NiCd, NiMH, or lead acid, would've been about all they had at the time.) The battery doesn't need to store too much during a trip, mostly just starting and stopping, making it very comparable to contemporary (to us) hybrid vehicles. Note regenerative braking is a must.
Although a large battery may be required after all, since cruise tends to be more than a few kW. Perhaps this would be solvable with better aerodynamics over aesthetics. Perhaps it wouldn't, as the sale cost would be incredibly high for this niche vehicle, even if we made the silly assumption that the fuel is near-zero cost.
Safety. NASA RTGs are made very safe, able to survive reentry in many cases. Even if not, it's likely that the contents are vaporized and spread over a wide area, diluted by the atmosphere, making the hazard even from a rather large one like Cassini's reasonably small.
Some info here: https://fas.org/nuke/space/gphs.pdf Note the graphite-composite construction, the same stuff used for Space Shuttle leading edge tiles.
Well, that's great for flight, there's an approximately zero chance of E.T. coming aboard brandishing a screwdriver.
Putting it in a vehicle is scary. And we have accidental experimental evidence (https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident) that this is so.
In short:
Whether or not the RTG is tightly sealed (say, thickly welded in multiple layers), and
Whether or not it is in any meaningful way repairable, and
Regardless of how obviously useful (or not) it is (in terms of electrical or thermal output),
Someone will fuck with it, break it down to its smallest components, break those up further, and spread contamination through their home, workplace, and those of anyone they sell or pass the parts to.
As for other nuclear devices -- fission reactors are controllable, but only within modest limits. A control system is required to manage the many time constants that fission entails, and a passive thermal dump is necessary for protection.
I don't know offhand how specific this is to various reactor styles; it's typical of commercial reactors (PWR, BWR, low temperature graphite-moderated ones, or hybrids like RBMK) so I'll assume it's still relevant here.
A notable characteristic of a fission reactor is, after operating for some time, decay products accumulate, and just as a pure decay source cannot be turned off, these cannot be turned off. This amounts to something like 5 or 10% of a commercial reactor's output, after, I suppose, some weeks or months of continuous operation.
Even if it's 1% for a daily-use vehicle, that's still, say, 1kW out of a 100kW peak demand, so we have a situation much like the RTG-hybrid hypothesized above. It must be able to dissipate that power passively, in the event that absolutely every other control and protection system fails, and the core SCRAMs. (Nevermind if the SCRAM systems don't go off...) Probably, loss of coolant should be one of those considerations, i.e., the core should be meltdown-proof even in the absence of cooling.
I don't know offhand if pebble-bed style, or other high temperature types, are more generous on this, but the high normal operating temperature does facilitate passive cooling, especially if you don't mind low efficiency.
LFTRs are straight out. You can talk containment and safety systems, but sooner or later, someone's going to breech exactly all of them, and the highly radioactive, highly mobile, very hot coolant-fuel will spray everywhere. Hot molten salt will boil moisture in concrete, spalling it, splashing itself around. The sizzling with moisture and organics will aerosolize the salt, carrying it into the air as fallout. It will dissolve in water (especially from the firehoses used to deal with the likely ignition caused by this), spreading further and carrying fallout into the water table.
Again, someone sooner or later will be curious enough, and dumb enough, to sit down with one of these things, and a grinder, and go at it. It might take minutes, it might take days, they will find the nasty surprise inside, and then all of us have to clean up their mess.
We can talk small (municipal) power stations perhaps, or even just cost-optimizing commercial nuke plants (mostly, saving paperwork?, while sacrificing a rational degree of safety), but putting any kind of nuclear material where thieves and idiots can get to it, hahahaha no.
Tim
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The world's stock of Pu238 is measured in tens of kilos/pounds. Here's a take on the subject:
https://www.wired.com/2013/09/plutonium-238-problem/ (https://www.wired.com/2013/09/plutonium-238-problem/)
Just forget this idea. It's great for Voyager 1 and 2, Curiosity and Gallileo etc. space missions, but otherwise not viable.
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OP. Besides the costs of the radioactive materials and the hazards and the disposal problems there are basic engineering problems such as the realistic operating efficiency. Read up on Carnot (thermal) efficiency then you can understand why RTGs work well when they're generating high temperatures and are operating in very cold environments (like space) but are a poor choice when operating in normal earth surface temperatures. The link provides, as an example, an operating temperature of 1500F (816C) and an environment of 70F. That's about as good as you're getting to get within the earths environment and it will go down from there.
https://en.wikipedia.org/wiki/Thermal_efficiency (https://en.wikipedia.org/wiki/Thermal_efficiency)
There are a lot of idiots on the internet that have no idea of what they're talking about. And there are plenty of people that are foolish enough to believe them!
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The world's stock of Pu238 is measured in tens of kilos/pounds. Here's a take on the subject:
https://www.wired.com/2013/09/plutonium-238-problem/ (https://www.wired.com/2013/09/plutonium-238-problem/)
Just forget this idea. It's great for Voyager 1 and 2, Curiosity and Gallileo etc. space missions, but otherwise not viable.
The guy on the internet also never mentioned what it costs to mine, extract, purify, ship, store or ultimately dispose of every pound of Pu that is manufactured. Go read up on the Manhattan Project; Hanford, Washington and Oak Ridge, Tennessee.
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There are a lot of idiots on the internet that have no idea of what they're talking about. And there are plenty of people that are foolish enough to believe them!
Amen! :-+
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I came across this video by Galen Winsor, & so are wondering how much of this knowledge is suppressed by the nuclear industry & military interests.
if what Galen Winsor is saying, is somehow true, see video, if you know your nuclear science!
if radioisotope thermoelectric powered electric vehicle, or atomic cars that never need gas, for the life of the vehicle.
in theory, a suitcase sized mini radioisotope thermoelectric battery will hypothetically power an electric vehicle for 15 to 20 years
or the life of vehicle. that never needs charging. vehicle powered by plutonium.
https://www.youtube.com/watch?v=8VvGw1tkT1Q (https://www.youtube.com/watch?v=8VvGw1tkT1Q)
Galen Winsor led a full life, dying at age 82 of old age diseases.
Plutonium is great stuff, and has been used to power space probes, remote sensing installations and arctic stations.
But, there is no Plutonium on earth, a major problem. The only way to get Plutonium is to irradiate Uranium 238 in a reactor
fueled with U235. Therefore, Plutonium is VERY expensive, like hundreds of thousands of US $ per ounce (maybe per gram).
The other issue is that a Plutonium-powered thermal generator just perks along at a steady (and very low) power output, based
on the natural disintegration rate of the isotope. So, you can't turn it on/off as needed. So, if it is to generate enough energy
to power a car, it needs to deliver several KW all the time, even when the car is parked in a garage. Now, a hybrid technology
where the RTG charges batteries would help this, but it breaks down when you want to take a long road trip. When the batteries
run down, you have to wait DAYS to recharge.
And, of course, there are other issues, like the NOT so insignificant radiation, the danger of some idiot releasing the material or
using it to make an A-bomb, or what could happen if a Plutonium car catches fire? Now, yes, the RTG-powered car would not
be so likely to catch fire as a gasoline car, but what if a gas car crashes into an RTG car and they both burn.
Just from the economics, it JUST AIN'T GONNA HAPPEN, I am quite sure. But, in fact, it won't work. The ONLY way to make it
work is to have a real fission reactor in a car. Works for submarines and aircraft carriers, I think it could probably (JUST barely)
be scaled down to fit in a car, but the shielding would never be practical. You'd need to get some 12 KW continuous output,
and use hybrid technology for the surges, hill climb, etc. How much Pu239 do you need to get a critical mass? Well, for a
nuclear weapon, a few Kg will do it, for a totally minimal reactor, it would take probably 8-10 Kg. So, everybody has enough
high-grade fissile material to make 2-3 A-bombs in their car? Not to mention it costing tens of millions of US $?
Jon
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The guy on the internet also never mentioned what it costs to mine, extract, purify, ship, store or ultimately dispose of every pound of Pu that is manufactured.
There are NO Pu mines. It has a short enough half-life that there is essentially NONE naturally on earth. It has to be manufactured, gram by gram, in a reactor.
Jon
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And, of course, there are other issues, like the NOT so insignificant radiation, the danger of some idiot releasing the material or
using it to make an A-bomb, or what could happen if a Plutonium car catches fire? Now, yes, the RTG-powered car would not
be so likely to catch fire as a gasoline car, but what if a gas car crashes into an RTG car and they both burn.
Heh, not much on that one, at least. All that graphite would have to be burning quite hot, for quite a long time, to expose the still-iridium-clad pellets (assuming a design similar to NASA's).
Radiation (under normal conditions) isn't a problem, they're pretty well shielded, even the space ones. Heavier (e.g. iron, lead) shielding, or for neutrons, hydrogen (usually as water, oil, polyethylene or the like) and boron, can easily be afforded in, probably around the same weight and size as a regular car engine.
All the rest are still unconscionably bad though. :P
Just from the economics, it JUST AIN'T GONNA HAPPEN, I am quite sure. But, in fact, it won't work. The ONLY way to make it
work is to have a real fission reactor in a car. Works for submarines and aircraft carriers, I think it could probably (JUST barely)
be scaled down to fit in a car, but the shielding would never be practical. You'd need to get some 12 KW continuous output,
and use hybrid technology for the surges, hill climb, etc. How much Pu239 do you need to get a critical mass? Well, for a
nuclear weapon, a few Kg will do it, for a totally minimal reactor, it would take probably 8-10 Kg. So, everybody has enough
high-grade fissile material to make 2-3 A-bombs in their car? Not to mention it costing tens of millions of US $?
Similar argument to the Air Force flying reactors -- the economy of scale you get with a Naval ship makes it more or less worthwhile (considering fitting, maintenance, refueling and decommissioning vs. tactical benefit), but even our largest aircraft it seems are just too power-to-weight sensitive, and not large enough to benefit from scale. So a car is definitely too small.
Tim
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I suppose nuclear power might work on trains. But it would be more reasonable to put the reactor in a fixed location and then route the power through the rails, which is actually how it's often done.
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So ... all you need is just a simple and ordinary car crash, will turn into mini dirty bomb ?
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So ... all you need is just a simple and ordinary car crash, will turn into mini dirty bomb ?
NASA's withstand a fall literally from space then crashing into the ground at whatever speed that is.
Tim
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So ... all you need is just a simple and ordinary car crash, will turn into mini dirty bomb ?
NASA's withstand a fall literally from space then crashing into the ground at whatever speed that is.
But NASA doesn't have greedy shareholders in their back, look what happened to Boeing now.
Even the whole trajectory and possible crash sites, was monitored closely and heavily guarded and secured (military grade) if the crash happened.
Essentially, NASA can afford to crash it.
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I suppose nuclear power might work on trains. But it would be more reasonable to put the reactor in a fixed location and then route the power through the rails, which is actually how it's often done.
In the USA, most of our electrical power (33.8%) came from natural gas, coal accounts for 30.4% and Nuclear is only 19.7%.
So it is 3 times more likely that either coal or natural gas is powering that rail than nuclear. But, comparing to carrying the power source on board, the reduction of complexity (thus cost) of remote power via rail is indeed superior, regardless of material source being nuclear, gas, coal, or whatever.
Reference:
Source of electrical power data are 2016 data from wikipedia here:
https://en.wikipedia.org/wiki/Coal_power_in_the_United_States
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Putting it in a vehicle is scary. And we have accidental experimental evidence (https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident) that this is so.
Damnit |O
Just when I thought that competent gangsters or militants getting their hands on that stuff would be worst :P
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I suppose nuclear power might work on trains. But it would be more reasonable to put the reactor in a fixed location and then route the power through the rails, which is actually how it's often done.
In the USA, most of our electrical power (33.8%) came from natural gas, coal accounts for 30.4% and Nuclear is only 19.7%.
So it is 3 times more likely that either coal or natural gas is powering that rail than nuclear.
I mean... it's about 0 times more likely in the US because the US has shit for trains. :palm:
France would be an example with:
1. predominantly nuclear power
2. lots of trains
3. that are high speed electric
Tim
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But if you look at RTG's then you see they are extremely expensive and have relatively very little power.
NASA uses the below RTG for example, 2,7kg and 215W for 11 years, you would need ten of those for your EV and still have not enough power, the RTG's will cost a multiple of the car itself.
Only 2.7kg and generates 215W*24h = 5.16 kWh/day? That's not too bad!
Still a non starter for the obvious reasons.
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Carnot (thermal) efficiency then you can understand why RTGs work well when they're generating high temperatures and are operating in very cold environments (like space) but are a poor choice when operating in normal earth surface temperatures. The link provides, as an example, an operating temperature of 1500F (816C) and an environment of 70F.
Except space is worse then running the thing in a planetary atmosphere! The background may be a few kelvin once you get away from a star or planet, But the only way to get the heat there is by radiation, and radiation losses go as the 4th power of absolute temperature.
If you look at the vacuum operating conditions for the thing you will find that the 'cold side' radiator is at closer to 600K then 3.5K, just due to the need to run the radiator hot enough to radiate the power input (Roughly 4kW of heat for less then 300W electrical, so the radiator is having to dump ~3.7kW of waste heat).
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If your "engine" throws a rod, you could wipe out a city.
From Cartalk, not me.